Ic Engine pune University MCQs

 This set of IC Engines Multiple Choice Questions & Answers  focuses on “Engine Performance Parameters”.

1. The ratio of indicated thermal efficiency to the corresponding air standard cycle efficiency is called ___________

a) net efficiency

b) efficiency ratio

c) relative efficiency

d) overall efficiency

Answer: c

Explanation: Relative efficiency is defined as the ratio of indicated thermal efficiency to the corresponding air standard cycle efficiency.

2. Compression ratio of I.C. engine is ___________

a) the ratio of volumes of air in cylinder before compression stroke and after compression stroke

b) volume displaced by piston per stroke and clearance volume in cylinder

c) ratio of pressure after compression and before compression

d) swept volume/cylinder volume

Answer: a

Explanation: None.

3. The air standard efficiency of an otto cycle compared to a diesel cycle for the given compression ratio is?

a) same

b) less

c) more

d) more or less depending on power rating

Answer: c

Explanation: None.

4. The calorific value of gaseous fuels is expressed in terms of ___________

a) Kcal

b) Kcal/kg

c) Kcal/m 2

d) Kcal/m 3

Answer: d

Explanation: None.

5. Indicated power of a 4-stroke engine is equal to ___________

a) pLAN

b) 2pLAN

c) pLAN/2

d) 4pLAN

Answer: c

Explanation: Indicated power of a 4-stroke engine is equal to pLAN/2.

where p = mean effective pressure,

L = stroke

A = area of piston and

N = rpm of engine.

6. If the intake air temperature of I.C. engine increases its efficiency will ___________

a) increase

b) decrease

c) remain same

d) none of the mentioned

Answer: b

Explanation: None.

7. All heat engines utilize ___________

a) low heat value of oil

b) high heat value of oil

c) net calorific value of oil

d) calorific value of fuel

Answer: a

Explanation: None.

8. An engine indicator is used to determine the following ___________

a) speed

b) temperature

c) volume of cylinder

d) m.e.p and I.H.P

Answer: d

Explanation: None.

9. Fuel oil consumption guarantees for I.C. engine are usually based on ___________

a) low heat value of oil

b) high heat value of oil

c) net calorific value of oil

d) calorific value of fuel

Answer: b

Explanation: None.

10. The thermal efficiency of a diesel cycle having fixed compression ratio, with increase in cut-off ratio will ___________

a) increase

b) decrease

c) be independent

d) none of the mentioned

Answer: b

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Air Standard Cycles”.

1. The air standard efficiency of an I.C. engine depends on _____________

a) fuel used

b) speed of engine

c) compression ratio

d) none of the mentioned

Answer: c

Explanation: None.

2. The specific fuel consumption per B.P. hour for a petrol engine is about ___________

a) 0.2 kg

b) 0.25 kg

c) 0.3 kg

d) 0.35 kg

Answer: b

Explanation: Generally, the specific fuel consumption per B.P. hour for a petrol engine is about 0.25 kg while the specific fuel consumption per B.P. hour for a diesel engine is about 0.2 kg.

3. The specific fuel consumption per B.P. hour for a diesel engine is about ___________

a) 0.2 kg

b) 0.25 kg

c) 0.3 kg

d) 0.35 kg

Answer: a

Explanation: Generally, the specific fuel consumption per B.P. hour for a diesel engine is about 0.2 kg while the specific fuel consumption per B.P. hour for a petrol engine is about 0.25 kg.

4. If the compression ratio in I.C. engine increases, then its thermal efficiency will ___________

a) increase

b) decrease

c) remain same

d) none of the mentioned

Answer: a

Explanation: The compression ratio in I.C. engine is directly proportional to the thermal efficiency, so as it increases, then its thermal efficiency will increase.

5. The thermal efficiency of petrol and gas engines is about ___________

a) 15%

b) 30%

c) 50%

d) 70%

Answer: b

Explanation: The thermal efficiency of petrol and gas engines is about 30% and the thermal efficiency of diesel engines is about 70%.

6. The thermal efficiency of diesel engines is about ___________

a) 15%

b) 30%

c) 50%

d) 70%

Answer: d

Explanation: The thermal efficiency of diesel engines is about 70% while the thermal efficiency of petrol and gas engines is about 30%.

7. The thermal efficiency of diesel engines on weak mixtures is ___________

a) unaffected

b) lower

c) higher

d) dependent on other factors

Answer: c

Explanation: None.

8. The volumetric efficiency of a well designed engine may be ___________

a) 30 to 40%

b) 40 to 60%

c) 60 to 70%

d) 75 to 90%

Answer: d

Explanation: None.

9. The working medium of an air standard cycle has constant ___________ throughout the cycle.

a) pressure

b) volume

c) specific heat

d) mass

Answer: c

Explanation: None.

10. It is assumed that all the processes of an air standard cycle are ___________

a) reversible

b) irreversible

c) adiabatic

d) isothermal

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Carnot Cycle”.

1. In a carnot cycle, the working medium receives heat at a _____________ temperature.

a) lower

b) higher

c) constant

d) none of the mentioned

Answer: b

Explanation: In a carnot cycle the working medium receives heat at a higher temperature and rejects heat at a lower temperature.

2. In a carnot cycle, the working medium rejects heat at a ____________ temperature.

a) lower

b) higher

c) constant

d) none of the mentioned

Answer: a

Explanation: In a carnot cycle the working medium receives heat at a higher temperature and rejects heat at a lower temperature.

3. In a carnot cycle, what is the working fluid?

a) a real gas

b) an ideal gas

c) a natural gas

d) none of the mentioned

Answer: b

Explanation: As Carnot cycle is an ideal cycle, so the working fluid is an ideal gas.

4. The isothermal process of a carnot cycle needs very __________ motion of the piston to maintain constant temperature.

a) slow

b) fast

c) medium

d) none of the mentioned

Answer: a

Explanation: The isothermal process of a carnot cycle needs very slow motion of the piston to maintain constant temperature while the adiabatic process needs very fast motion to complete the adiabatic process.

5. The adiabatic process of a carnot cycle needs very __________ motion to complete the adiabatic process.

a) slow

b) fast

c) medium

d) none of the mentioned

Answer: b

Explanation: The isothermal process of a carnot cycle needs very slow motion of the piston to maintain constant temperature while the adiabatic process needs very fast motion to complete the adiabatic process.

6. For a given temperature T 1 , as the difference between T 1 and T 2 increases, the COP of a carnot heat pump ___________

a) increases

b) decreases

c) first increases, then decreases

d) none of the mentioned

Answer: b

Explanation: COP = T 1 /(T 1 – T 2 )

As the value of T 1 – T 2 increases, value of COP decreases.

7. A carnot heat pump is used to heat a house. The outside temperature is -3ºC and the indoor temperature is 27ºC. If the heat loss from the house is 40kW, the power required to operate the heat pump is?

a) 1kW

b) 2kW

c) 3kW

d) 4kW

Answer: d

Explanation: COP = Heat loss/Work done = T 1 /(T 1 – T 2 )

or, 40/ Work done = 273 + 27/27-

or, Work done = 40 x 30/300 = 4kW.

8. A carnot cycle is to be designed to attain efficiency of 0.75. if temperature of high temperature reservoir is 727ºC, then low temperature reservoir will have to be maintained at ___________

a) 23ºC

b) 181ºC

c) -23ºC

d) -181ºC

Answer: c

Explanation: Carnot efficiency = T 2 – T 1 /(T 2 +273)

or, 0.75 = 727- T 1 /

or, 0.75×1000 = 727- T1

or, – T 1 = 750-727

or, T 1 = -23ºC.

9. A cyclic heat engine does 50kJ of work per cycle. If efficiency of engine is 75%, the heat rejected per cycle will be ___________

a) 60.6kJ

b) 16.6kJ

c) 66.6kJ

d) 200kJ

Answer: b

Explanation: Carnot efficiency = Work done/Heat supplied(Q 1 )

0.75 = 50/ Q 1

or, Q 1 = 200/3

and, Work done = Q 1 – Q 2

or, Q 2 = 200/3-50 = 50/3 = 16.6kJ.

10. A carnot cycle refrigerator operates between 250ºK and 300ºK. What is the value of COP?

a) 10

b) 20

c) 25

d) 5

Answer: d

Explanation: COP = T 2 /(T 1 – T 2 )

= 250/300-250

= 5.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Stirling Cycle And Ericsson Cycle”.

1. The Stirling cycle consists of ___________

a) two isothermal and two constant pressure processes

b) two isothermal and two constant volume processes

c) two isothermal and two adiabatic processes

d) none of the mentioned

Answer: b

Explanation: None.

2. In a Stirling cycle, the heat rejection and addition takes place at constant ___________

a) pressure

b) volume

c) temperature

d) none of the mentioned

Answer: c

Explanation: None.

3. If Stirling cycle with regenerative arrangement and Carnot cycle operate within same temperature limits, then the thermal efficiency of Carnot cycle will be ___________

a) same

b) half

c) twice

d) none of the mentioned

Answer: a

Explanation: None.

4. The Ericsson cycle consists of ___________

a) two isothermal and two constant pressure processes

b) two isothermal and two constant volume processes

c) two isothermal and two adiabatic processes

d) none of the mentioned

Answer: a

Explanation: The Ericsson cycle consists of two isothermal and two constant pressure processes while the Stirling cycle consists of two isothermal and two constant volume processes.

5. Stirling and Ericsson cycles are ___________

a) reversible cycles

b) irreversible cycles

c) quasi-static cycles

d) semi-reversible cycles

Answer: a

Explanation: None.

6. The efficiency of Stirling cycle is _____________ Carnot cycle.

a) greater than

b) less than

c) equal to

d) none of the mentioned

Answer: c

Explanation: None.

7. The concept of regeneration is used in which of the following cycles?

a) Rankine and Stirling

b) Rankine and Ericsson

c) Ericsson and Stirling

d) None of the mentioned

Answer: c

Explanation: None.

8. The efficiency of Ericsson cycle is ___________ Carnot cycle.

a) greater than

b) less than

c) equal to

d) none of the mentioned

Answer: c

Explanation: None.

9. Both the Ericsson cycle and Joule’s cycle have two constant pressure processes.

a) True

b) False

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Otto Cycle”.

1. The thermal efficiency of a standard Otto cycle for a compression ratio of 5.5 will be ___________

a) 25%

b) 50%

c) 70%

d) 100%

Answer: b

Explanation: None.

2. The efficiency of an Otto cycle is increased by increasing ___________

a) pressure ratio

b) compression ratio

c) temperature ratio

d) none of the mentioned

Answer: b

Explanation: None.

3. The Otto cycle consists of ___________

a) two constant pressure processes and two constant volume processes

b) two constant pressure and two constant entropy processes

c) two constant volume processes and two constant entropy processes

d) none of the mentioned

Answer: b

Explanation: None.

4. The thermal efficiency of theoretical Otto cycle ___________

a) decreases with increase in compression ratio

b) increases with decrease in compression ratio

c) does not depends upon the pressure ratio

d) none of the mentioned

Answer: c

Explanation: None.

5. What is the work output of the theoretical Otto cycle?

a) increases with increase in compression ratio

b) increases with increase in pressure ratio

c) increases with increase in compression & pressure ratio

d) none of the mentioned

Answer: c

Explanation: None.

6. The mean effective pressure of an Otto Cycle increases with an increase in ___________

a) pressure ratio

b) compression ratio

c) temperature ratio

d) none of the mentioned

Answer: b

Explanation: The mean effective pressure of an Otto Cycle is directly proportional to its compression ratio, so it increases with an increase in compression ratio.

7. In Otto cycle, heat addition takes place at ___________

a) constant temperature

b) constant pressure

c) constant volume

d) none of the mentioned

Answer: c

Explanation: None.

8. If compression ratio of an engine working on Otto cycle is increased from 5 to 6, its air standard efficiency will increase by ___________

a) 1%

b) 20%

c) 16.67%

d) 8%

Answer: d

Explanation: None.

9. If the compression ratio of an engine working on Otto cycle is increased from 5 to 7, the percentage increase in efficiency will be ___________

a) 2%

b) 4%

c) 8%

d) 14%

Answer: d

Explanation: None.

10. The constant volume cycle is also called ___________

a) Carnot cycle

b) Joule cycle

c) Diesel cycle

d) Otto cycle

Answer: d

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Diesel Cycle”.

1. Diesel cycle is also known as _____________

a) constant volume cycle

b) constant pressure cycle

c) constant temperature cycle

d) none of the mentioned

Answer:b

Explanation: Diesel cycle is also known as constant pressure cycle as pressure is constant in this cycle.

2. A diesel engine has compression ratio from ____________

a) 6 to 10

b) 10 to 15

c) 16 to 20

d) 25 to 40

Answer: c

Explanation: None.

3. In Diesel cycle, heat addition takes place at ____________

a) constant temperature

b) constant pressure

c) constant volume

d) none of the mentioned

Answer: b

Explanation: None.

4. The combustion in compression ignition engine is ____________

a) homogeneous

b) heterogeneous

c) laminar

d) none of the mentioned

Answer: b

Explanation: None.

5. In a diesel engine, the fuel is ignited by ____________

a) spark

b) injected fuel

c) heat resulting from compressing air that is supplied for combustion

d) combustion chamber

Answer: c

Explanation: None.

6. The thermal efficiency of a diesel cycle having fixed compression ratio, with increase in cut-off ratio will ____________

a) increase

b) decrease

c) be independent

d) none of the mentioned

Answer: b

Explanation: None.

7. The pressure at the end of compression, in diesel engines, is approximately ____________

a) 10 bar

b) 20 bar

c) 25 bar

d) 35 bar

Answer: d

Explanation: None.

8. What is the combustion in spark ignition engine?

a) homogeneous

b) heterogeneous

c) laminar

d) none of the mentioned

Answer: a

Explanation: The combustion in spark ignition engine is homogeneous while the combustion in compression ignition engine is heterogeneous.

9. If the temperature of intake air in I.C. engine is lowered, then its efficiency will ____________

a) increase

b) decrease

c) remain same

d) increase up to a certain limit and then decrease

Answer: a

Explanation: None.

10. The fuel in diesel engine is normally injected at pressure of ____________

a) 5-10 kg/cm 2

b) 20-25 kg/cm 2

c) 60-80 kg/cm 2

d) 90-130 kg/cm 2

Answer: d

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Dual Cycle”.

1. Dual Cycle is a combination of ____________

a) Otto cycle and Diesel cycle

b) Otto cycle and Stirling cycle

c) Brayton cycle and steam cycle

d) None of the mentioned

Answer: a

Explanation: None.

2. Dual cycle is also known as ____________

a) Diesel cycle

b) Joule cycle

c) Mixed cycle

d) None of the mentioned

Answer: c

Explanation: Another name for Dual cycle is a mixed cycle.

3. In Dual cycle, heat addition takes place ____________

a) at Constant volume

b) first at constant volume then at constant pressure

c) constant pressure

d) none of the mentioned

Answer: b

Explanation: Since, Dual Cycle is a combination of Otto cycle and Diesel cycle, so in Dual cycle, generally heat addition takes place first at constant volume then at constant pressure.

4. In Dual cycle, heat rejection takes place ____________

a) at constant volume

b) first at constant volume then at constant pressure

c) constant pressure

d) none of the mentioned

Answer: a

Explanation: Since, Dual Cycle is a combination of Otto cycle and Diesel cycle, so in Dual cycle, generally heat rejection takes place at constant volume.

5. Most high speed compression engines operate on ____________

a) Otto cycle

b) Diesel Cycle

c) Dual cycle

d) Carnot cycle

Answer: c

Explanation: None.

6. In a standard dual air cycle, for a fixed amount of heat supplied and a fixed value of compression ratio, the mean effective pressure ____________

a) shall increase with increase in r p and decreases in r c

b) shall increase with decrease in r p and increases in r c

c) shall remain independent of r p

d) shall remain independent of r c

Answer: a

Explanation: None.

7. The thermal efficiency of a diesel engine on weak mixtures is ____________

a) unaffected

b) lower

c) higher

d) none of the mentioned

Answer: c

Explanation: None.

8. The volumetric efficiency of a well designed engine may be ____________

a) 30 to 40%

b) 40 to 60%

c) 60 to 70%

d) 75 to 90%

Answer: d

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Comparison Of Otto, Diesel And Dual Cycle”.

1. For same compression ratio and for same heat added ____________

a) Otto cycle is more efficient than Diesel Cycle

b) Diesel cycle is more efficient than Otto Cycle

c) Efficiency depends on other factors

d) None of the mentioned

Answer: a

Explanation: None.

2. The efficiency of Carnot cycle is maximum for ____________

a) gas engine

b) petrol engine

c) steam engine

d) reversible engine

Answer: d

Explanation: None.

3. For the same compression ratio, the efficiency of dual combustion cycle is?

a) greater than otto cycle

b) less than diesel cycle

c) less than otto cycle and greater than diesel cycle

d) greater than both otto and diesel cycle

Answer: c

Explanation: None.

4. If both Stirling and Carnot cycles operate within the same temperature limits, then efficiency of Stirling cycle as compared to Carnot cycle is?

a) more

b) less

c) equal

d) none of the mentioned

Answer: c

Explanation: None.

5. Choose the correct statement from the following.

a) Diesel cycle is more efficient than Otto cycle for a given compression ratio

b) Otto cycle is more efficient than Diesel cycle for a given compression ratio

c) For a given compression ratio, both Otto and Diesel cycles have same efficiency

d) None of the mentioned

Answer: b

Explanation: Otto cycle is more efficient than Diesel cycle for a given compression ratio.

6. For constant maximum pressure and heat input, the air standard efficiency of the gas power cycle is in the order.

a) Diesel cycle, Dual cycle, Otto cycle

b) Otto cycle, Diesel cycle, Dual cycle

c) Dual cycle, Otto cycle, Diesel cycle

d) Diesel cycle, Otto cycle, Dual cycle

Answer: a

Explanation: None.

7. Otto cycle efficiency is higher than Diesel cycle efficiency for the same compression ratio and heat input because in Otto cycle ____________

a) combustion is at constant volume

b) expansion and compression are isentropic

c) maximum temperature is higher

d) heat rejection is lower

Answer: d

Explanation: None.

8. The thermal efficiency of a diesel engine is about ____________

a) 15%

b) 30%

c) 50%

d) 70%

Answer: b

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Fuel Air Cycle”.

1. The air fuel ratio of the petrol engine is controlled by ____________

a) fuel pump

b) governor

c) injector

d) carburettor

Answer: d

Explanation: The air fuel ratio of the petrol engine is controlled by carburettor and not by injector or fuel pump.

2. Fuel consumption of diesel engines is not guaranteed at one quarter load because at such low loads ____________

a) the friction is high

b) the friction is unpredictable

c) the small difference in cooling water temperature or in internal friction has a disproportionate effect

d) the engine is rarely operated

Answer: c

Explanation: None.

3. The fuel air ratio in a petrol engine fitted with suction carburettor, operating with dirty air filter as compared to clean filter will be ____________

a) higher

b) lower

c) remain unaffected

d) none of the mentioned

Answer: a

Explanation: None.

4. The theoretically correct air fuel ratio for petrol engine is of the order of ____________

a) 6:1

b) 9:1

c) 12:1

d) 15:1

Answer: d

Explanation: None.

5. Air fuel ratio for idling speed of a petrol engine is approximately ____________

a) 1:1

b) 5:1

c) 10:1

d) 15:1

Answer: c

Explanation: None.

6. Air fuel ratio at which a petrol engine can not work is?

a) 8:1

b) 10:1

c) 15:1

d) 20:1 and less

Answer: d

Explanation: None.

7. For maximum power generation, the air fuel ratio for a petrol engine of vehicles, is of the order of ____________

a) 9:1

b) 12:1

c) 15:1

d) 18:1

Answer: b

Explanation: None.

8. The following volume of air is required for consuming 1 litre of fuel by a four stroke engine is?

a) 1m 3

b) 2.5m 3

c) 5-6m 3

d) 9-10m 3

Answer: d

Explanation: 9-10m 3 volume of air is required for consuming 1 litre of fuel by a four stroke engine.

9. Diesel engine can work on very lean air fuel ratio of the order of 30:1. A petrol engine can also work on such a lean ratio provided?

a) it is properly designed

b) best quality fuel is used

c) can not work as it is impossible

d) flywheel size is proper

Answer: c

Explanation: Petrol engine cannot work below air fuel ratio 20:1.

10. A stoichiometric air fuel ratio is ____________

a) chemically correct mixture

b) lean mixture

c) rich mixture for idling

d) rich mixture for over loads

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Dissociation”.

1. Dissociation is the disintegration of burnt gases at __________ temperatures.

a) low

b) high

c) constant

d) none of the mentioned

Answer: b

Explanation: None.

2. In lean mixtures no dissociation takes place at _____________ temperatures.

a) low

b) high

c) constant

d) none of the mentioned

Answer: a

Explanation: None.

3. In rich mixtures dissociation is prevented by the available ____________

a) CO

b) CO 2

c) O 2

d) CO and O 2

Answer: d

Explanation: None.

4. Power output is maximum at stoichiometric ratio where there is ____________

a) dissociation

b) no dissociation

c) rich mixture

d) none of the mentioned

Answer: b

Explanation: None.

5. Maximum dissociation is for ____________

a) lean mixture

b) rich mixture

c) stoichiometric

d) none of the mentioned

Answer: c

Explanation: Maximum dissociation is for stoichiometric mixtures while in lean mixtures, generally no dissociation takes place.

6. With dissociation, peak temperature is obtained ____________

a) at the stoichiometric ratio

b) when the mixture is slightly lean

c) when the mixture is slightly rich

d) none of the mentioned

Answer: c

Explanation: None.

7. With dissociation the exhaust gas pressure ____________

a) decreases

b) increases

c) no effect

d) increases upto certain air fuel ratio and then decreases

Answer: a

Explanation: None.

8. For a given compression ratio, as the mixture is made progressively rich from lean the mean effective pressure ____________

a) increases

b) decreases

c) initially increases then decreases

d) remains more or less same

Answer: c

Explanation: None.

9. When the mixture is lean ____________

a) efficiency is less

b) power output is less

c) maximum temperature and pressure are higher

d) all of the mentioned

Answer: b

Explanation: Power output is less when the mixture is lean.

10. For a compressor process with variable specific heat the peak temperature and pressure are ____________

a) lower

b) higher

c) no effect

d) none of the mentioned

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Actual Cycle”.

1. Time loss factor in Actual Cycle is due to ____________

a) progressive combustion

b) heat loss through cylinder walls

c) gas leakage

d) friction

Answer: a

Explanation: None.

2. If the spark timing is at TDC, the work is ____________

a) more

b) less

c) equal

d) none of the mentioned

Answer: b

Explanation: If the spark timing is at TDC, the work is less as the peak pressure is low.

3. When the spark is advanced, the work output is less as ____________

a) the peak pressure is low

b) the peak temperature is low

c) additional work is required to compress the burning gas

d) frictional losses increase

Answer: c

Explanation: When the spark is advanced, the work output is less as additional work is required to compress the burning gas.

4. Optimum spark timing gives ____________

a) higher mean effective pressure

b) higher efficiency

c) higher mean effective pressure and higher efficiency

d) none of the mentioned

Answer: c

Explanation: None.

5. The major loss in a S.I. engine is due to ____________

a) exhaust blow down

b) pumping

c) incomplete combustion

d) variation in specific heat and chemical equilibrium

Answer: d

Explanation: The major loss in a S.I. engine is due to variation in specific heat and chemical equilibrium while the major loss in a C.I. engine is loss due to incomplete combustion.

6. What is the major loss in a C.I. engine?

a) direct heat loss

b) loss due to incomplete combustion

c) rubbing friction loss

d) pumping loss

Answer: b

Explanation: None.

7. In an actual S.I engine the pumping loss with respect to speed ____________

a) increases

b) decreases

c) remains same

d) none of the mentioned

Answer: b

Explanation: None.

8. The volumetric efficiency is affected by ____________

a) the exhaust gas in the clearance volume

b) the design of intake and exhaust valve

c) valve timing

d) all of the mentioned

Answer: d

Explanation: None.

9. In petrol engine the actual pressure developed compared to the predicted maximum pressure is?

a) 90%

b) 70%

c) 50%

d) 25%

Answer: c

Explanation: In petrol engine the actual pressure developed compared to the predicted maximum pressure is 50% while energy released in actual cycle is about 90% of the fuel input.

10. Energy released in actual cycle is about _____________ of the fuel input.

a) 90%

b) 70%

c) 50%

d) 25%

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Comparison of Air Cycle and Fuel Cycle”.

1. The actual efficiency of a good engine is about _____________ of the estimated air fuel cycle efficiency.

a) 100%

b) 85%

c) 50%

d) 25

Answer: b

Explanation: None.

2. The ratio of the actual efficiency and the fuel air cycle efficiency for C.I. engines is about ____________

a) 0.2-0.3

b) 0.5-0.6

c) 1.0

d) 0.6-0.8

Answer: d

Explanation: None.

3. Fuel air efficiency is less than air standard efficiency by an amount equal to ____________

a) pumping loss

b) friction loss

c) loss due to specific heat and chemical equilibrium

d) exhaust blow down loss

Answer: c

Explanation: None.

4. Fuel air ratio affects maximum power output of the engine due to ____________

a) higher specific heats

b) chemical equilibrium losses

c) all of the mentioned

d) none of the mentioned

Answer: c

Explanation: None.

5. As compared to air cycle, in actual working, What is the effect of variation in specific heats?

a) increase maximum pressure and maximum temperature

b) reduce maximum pressure and maximum temperature

c) increase maximum pressure and decrease maximum temperature

d) none of the mentioned

Answer: b

Explanation: None.

6. The ratio of actual cycle efficiency to that of the ideal cycle efficiency is called ____________

a) effectiveness

b) work ratio

c) efficiency ratio

d) net efficiency

Answer: c

Explanation: Efficiency ratio is the ratio of actual cycle efficiency to that of the ideal cycle efficiency.

7. The ignition of charge by some hot surface in the engine cylinder before operation of spark plug is known as ____________

a) auto ignition

b) pre-ignition

c) detonation

d) none of the mentioned

Answer: b

Explanation: Pre-ignition is defined as the ignition of charge by some hot surface in the engine cylinder before operation of spark plug.

8. The brake mean effective pressure of an I.C. engine with an increase in speed will ____________

a) increase

b) decrease

c) remain same

d) none of the mentioned

Answer: c

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Effects Of Operating Variables”.

1. The fuel air cycle efficiency _______________ with the compression ratio.

a) increases

b) decreases

c) remains same

d) none of the mentioned

Answer: a

Explanation: As the compression ratio is increased the efficiency of fuel air cycle also increases as there is more scope of expansion work.

2. Fuel ratio is defined as the ratio of actual fuel air ratio to chemically correct fuel air ratio on mass basis.

a) True

b) False

Answer: b

Explanation: Actually, equivalence ratio is defined as the ratio of actual fuel air ratio to chemically correct fuel air ratio on mass basis.

3. The maximum pressure and maximum temperature ____________ with compression ratio.

a) increases

b) decreases

c) remains same

d) none of the mentioned

Answer: a

Explanation: Since, the temperature and pressure at the end of compression are higher, so, as a result the maximum pressure and maximum temperature increases with compression ratio.

4. As the mixture is made lean the temperature rise due to combustion will be lowered.

a) True

b) False

Answer: a

Explanation: When the mixture is made lean the temperature rise due to combustion will be lowered as a result of reduced energy input per unit mass of mixture.

5. Fuel air ratio affects maximum power output of the engine due to ____________

a) higher specific heats

b) chemical equilibrium losses

c) higher specific heats and chemical equilibrium losses

d) none of the mentioned

Answer: c

Explanation: Due to both higher specific heats and chemical equilibrium losses, the fuel air ratio affects the maximum power output of the engine.

6. Mean effective pressure at a given compression ratio is maximum when the air fuel ratio is?

a) higher than stoichiometric

b) lower than stoichiometric

c) equal to stoichiometric

d) none of the mentioned

Answer: b

Explanation: When the air fuel ratio is lower than stoichiometric then only the mean effective pressure at a given compression ratio is maximum.

7. For a compression process with variable specific heat the peak temperature and pressure are _____________ as compared to constant specific heat.

a) lower

b) higher

c) no effect

d) none of the mentioned

Answer: a

Explanation: The peak temperature and pressure are lower for a compression process with variable specific heat as compared to constant specific heat.

8. Cycles with lean to very lean mixture tend towards ____________

a) practice cycles

b) fuel air cycles

c) air standard cycles

d) none of the mentioned

Answer: d

Explanation: All the cycles mentioned above operates only on high mixtures.

9. When the mixture is lean ____________

a) efficiency is less

b) power output is less

c) maximum temperature and pressure are higher

d) all of the mentioned

Answer: b

Explanation: Power output is directly proportional to mixture, so when the mixture is lean, the power output is less and vice-versa.

10. For a given compression ratio, as the mixture is made progressively rich from lean the mean effective pressure ____________

a) increases

b) decreases

c) initially increases and then decreases

d) remains more or less the same

Answer: c

Explanation: To get a stable condition, for a given compression ratio, as the mixture is made progressively rich from lean the mean effective pressure.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Fuels”.

1. Ignition quality of petrol is expressed by?

a) octane number

b) calorific value

c) self ignition temperature

d) cetane number

Answer: a

Explanation: Ignition quality of petrol is expressed by octane number and that of diesel by cetane number.

2. Petrol is distilled at a temperature in range of ______________

a) 30-65ºC

b) 65-220ºC

c) 220-350ºC

d) 350-450ºC

Answer: b

Explanation: Petrol is distilled at a temperature in range of 65-220ºC while kerosene is distilled at 220-350ºC.

3. Kerosene is distilled at ____________

a) 30-65ºC

b) 65-220ºC

c) 220-350ºC

d) 350-450ºC

Answer: c

Explanation: Kerosene is distilled at 220-350ºC and petrol is distilled at a temperature in range of 65-220ºC.

4. Self-ignition temperature of petrol is of the order of ____________

a) 150ºC

b) 240ºC

c) 370ºC

d) more than 500ºC

Answer: d

Explanation: None.

5. What is Iso-octane?

a) It has an octane number of 0

b) It has an octane number of 50

c) It has an octane number of 100

d) none of the mentioned

Answer: c

Explanation: None.

6. Octane number is determined by comparing the performance of petrol with the following hydro-carbons?

a) iso-octane

b) mixture of normal heptane and iso octane

c) alpha methyl napthalene

d) none of the mentioned

Answer: b

Explanation: None.

7. What is Cetane?

a) It has zero cetane number

b) It has 100 cetane number

c) It helps detonation

d) It is a straight chain paraffin

Answer: d

Explanation: None.

8. Ethyl fluid is used ___________

a) to increase the octane rating of the fuel

b) to increase the cetane rating of the fuel

c) as a defrosting agent

d) none of the mentioned

Answer: a

Explanation: For practical purposes, ethyl fluid is used to increase the octane rating of the fuel.

9. Normal heptane ___________

a) accelerates auto-ignition

b) helps to resist auto-ignition

c) does not affect auto-ignition

d) none of the mentioned

Answer: a

Explanation: None.

10. Which of the following is the lightest and most volatile liquid fuel?

a) diesel

b) petrol

c) gasoline

d) fuel oil

Answer: c

Explanation: Gasoline is the lightest and most volatile liquid fuel.

11. Polymerization is a chemical process in which molecules of a compound become ___________

a) larger

b) smaller

c) liquid

d) gaseous

Answer: a

Explanation: Polymerization is defined as a chemical process in which molecules of a compound become larger.

12. Diesel fuel, compared to petrol is ___________

a) less difficult to ignite

b) just about the same difficult to ignite

c) more difficult to ignite

d) none of the mentioned

Answer: c

Explanation: None.

13. In a diesel engine the diesel fuel injected into cylinder would burn instantly at about compressed air temperature of ___________

a) 250ºC

b) 500ºC

c) 1000ºC

d) 1500ºC

Answer: c

Explanation: None.

14. When crude oil is heated, then which of the following hydrocarbon is given off first?

a) kerosene

b) gasoline

c) paraffin

d) natural gas

Answer: d

Explanation: When crude oil is heated, then natural gas is given off first.

15. Gaseous fuel guarantees are based on ___________

a) calorific value of oil

b) low heat value of oil

c) mean heat value of oil

d) none of the mentioned

Answer: b

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Qualities Of Fuel”

1. The rating of a diesel engine, with an increase in air inlet temperature, will ___________

a) increase linearly

b) decrease linearly

c) increase parabolically

d) decrease parabolically

Answer: b

Explanation: None.

2. The knock in diesel engine occurs due to ___________

a) instantaneous and rapid burning of the first part of the charge

b) instantaneous auto ignition of last part of charge

c) reduction of delay period

d) none of the mentioned

Answer: a

Explanation: None.

3. What is volatility of diesel fuel?

a) maximum temperature to which oil is heated in order to give off inflammable vapour in sufficient quantity to ignite momentarily when bought in contact with a flame

b) it catches fire without external aid

c) indicated by 90% distillation temperature

d) none of the mentioned

Answer: c

Explanation: None.

4. Violent sound pulsations within the cylinder of an I.C. engine are caused due to ___________

a) heavy turbulence

b) improved scavenging

c) detonation

d) pre-ignition

Answer: c

Explanation: None.

5. What is Auto-ignition temperature?

a) maximum temperature to which oil is heated in order to give off inflammable vapour in sufficient quantity to ignite momentarily when bought in contact with a flame

b) that at which it catches fire without external aid

c) indicated by 90% distillation temperature

d) none of the mentioned

Answer: b

Explanation: Auto-ignition temperature is defined as that temperature at which it catches fire without external aid while volatility of diesel fuel is indicated by 90% distillation temperature.

6. What is Ignition lag?

a) the time taken by fuel after injection to reach upto auto-ignition temperature

b) time before actual fuel injection and the pump plunger starts to pump fuel

c) time corresponding to actual injection and top dead center

d) none of the mentioned

Answer: a

Explanation: None.

7. The delay period in petrol engine is of the order of ___________

a) 0.001 sec

b) 0.002 sec

c) 0.01 sec

d) 0.1 sec

Answer: b

Explanation: None.

8. Detonation is caused by which of the following unstable compounds?

a) peroxides, aldehydes, and ketones

b) peroxides, aldehydes, oxides, and sulphides

c) aldehydes, oxides, and ketones

d) none of the mentioned

Answer: a

Explanation: Detonation is caused by peroxides, aldehydes, and ketones.

9. In order to prevent knock in the S.I. engines, the charge away from the spark plug should have ___________

a) low temperature

b) low density

c) rich mixture

d) all of the mentioned

Answer: d

Explanation: None.

10. To reduce the possibility of knock in C.I. engines, the first elements of fuel and air should have ___________

a) high temperature

b) high density

c) short delay

d) all of the mentioned

Answer: d

Explanation: None.

11. The detonation tendency in petrol engines for specified conditions of fuel rating, compression ratio, speed, etc, can be controlled by having ___________

a) smaller cylinder bore

b) bigger cylinder bore

c) medium cylinder bore

d) none of the mentioned

Answer: a

Explanation: None.

12. A fuel will detonate less if it has ___________

a) higher self ignition temperature

b) lower self ignition temperature

c) proper self ignition temperature

d) none of the mentioned

Answer: a

Explanation: None.

13. Ignition quality of diesel fuel oil is expressed by an index called ___________

a) octane number

b) cetane number

c) calorific value

d) none of the mentioned

Answer: b

Explanation: Cetane number is defined as the ignition quality of diesel fuel oil is expressed by an index.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Rating Of Fuels”.

1. For best results of efficient combustion, high speed diesel engines need an approximate cetane number of _____________

a) 100

b) 10

c) 50

d) 5

Answer: c

Explanation: None.

2. Calorific value of diesel oil is of the order of ___________

a) 3000 kcal/kg

b) 5000 kcal/kg

c) 7500 kcal/kg

d) 10000 kcal/kg

Answer: d

Explanation: None.

3. Carbon residue in diesel oil should not be more than ___________

a) 1%

b) 0.5%

c) 0.1%

d) 0.01%

Answer: c

Explanation: None.

4. Which is the most popular firing order in the case of four cylinder in-line I.C. engine?

a) 1-2-3-4

b) 1-3-2-4

c) 1-4-2-3

d) 1-3-4-2

Answer: d

Explanation: None.

5. What is the compression ratio of motor cars?

a) 5

b) 7

c) 10

d) 13

Answer: b

Explanation: None.

6. What is the specific gravity of diesel oil?

a) 1

b) 0.7

c) 0.85

d) 0.5

Answer: c

Explanation: None.

7. Freezing temperature of petrol is about ___________

a) 0.65

b) 0.75

c) 0.85

d) 0.95

Answer: b

Explanation: None.

8. Choose the correct statement, detonation can be controlled by ___________

a) varying compression ratio

b) using lean mixture

c) retarding the spark timing

d) reducing the r.p.m

Answer: c

Explanation: Detonation can be controlled by retarding the spark timing.

9. The efficiency of I.C. engines normally is of the order of ___________

a) 15-20%

b) 20-25%

c) 25-30%

d) 30-35%

Answer: d

Explanation: None.

10. What is the firing order of a six stroke I.C. engine?

a) 1-3-6-5-2-4

b) 1-4-2-5-6-3

c) 1-6-2-5-4-3

d) 1-5-3-4-2-6

Answer: d

Explanation: The firing order of a six stroke I.C. engine is 1-5-3-4-2-6 and the firing order in the case of four cylinder in-line I.C. engine is 1-3-4-2.

11. Sulphur content in diesel engine oil should not be more than ___________

a) 10%

b) 5%

c) 1%

d) 0.1%

Answer: c

Explanation: None.

12. The ash content in diesel oil should not be more than ___________

a) 1%

b) 5%

c) 0.1%

d) 0.01%

Answer: d

Explanation: The ash content in diesel oil should not be more than 0.01% while sulphur content in diesel engine oil should not be more than 1%.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Alternate Fuels”.

1. What is the advantage of gaseous fuel?

a) it can be stored easily

b) it can mix easily with air

c) it can displace more air from the engine

d) all of the mentioned

Answer: b

Explanation: None.

2. Paraffins are generally represented by ___________

a) C n H n

b) C n H 2n

c) C n H 2n+2

d) C n H 2n-6

Answer: c

Explanation: Paraffins are generally represented by C n H 2n+2 while olefins are generally represented by C n H n .

3. Paraffins have molecular structure of ___________

a) chain saturated

b) chain unsaturated

c) ring saturated

d) ring unsaturated

Answer: a

Explanation: None.

4. Olefins are generally represented by ___________

a) C n H n

b) C n H 2n

c) C n H 2n+2

d) C n H 2n-6

Answer: a

Explanation: Olefins are represented by C n H n and paraffins are generally represented by C n H 2n+2 .

5. Hydrocarbons are decomposed into smaller hydrocarbons by ___________

a) reforming

b) refining

c) cracking

d) polymerization

Answer: c

Explanation: Hydrocarbons are decomposed into smaller hydrocarbons by cracking while the molecular structure of the straight-run gasoline is changed by reforming.

6. The molecular structure of the straight-run gasoline is changed by ___________

a) reforming

b) refining

c) cracking

d) boiling

Answer: a

Explanation: The molecular structure of the straight-run gasoline is changed by reforming and hydrocarbons are decomposed into smaller hydrocarbons by cracking.

7. Which is the most preferred S.I. engines fuel?

a) aromatics

b) paraffins

c) olefins

d) napthenes

Answer: a

Explanation: For S.I. engines fuel most preferred are aromatics while for C.I. engines fuel most preferred are paraffins.

8. Which is the most preferred C.I. engines fuel?

a) aromatics

b) paraffins

c) olefins

d) napthenes

Answer: b

Explanation: For C.I. engines fuel most preferred are paraffins and for S.I. engines fuel most preferred are aromatics.

9. In spark ignition engines, the knocking tendency can be decreased by ______________

a) decreasing compression ratio

b) controlling intake throttle

c) controlling ignition timing

d) adding dopes like tetraethyl lead and ethylene dibromide

Answer: d

Explanation: None.

10. Detonation in petrol engines can be suppressed or reduced by the addition of small quantity of ___________

a) lead nitrate

b) iso-octane

c) n-heptane

d) none of the mentioned

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Surface Ignition Alcohol C.I. Engine”.

1. Which of the following statement is not correct with respect to alcohols as alternate fuel in IC engines?

a) anti-knock characteristics of alcohol is poor

b) alcohol contains about half the heat energy of gasoline/litre

c) alcohol does not vaporize as easily as gasoline

d) alcohols are corrosive in nature

Answer: a

Explanation: Anti-knock characteristics of alcohol is good.

2. What is the mixture of Gasohol?

a) 90% ethanol + 10% gasoline

b) 10% ethanol + 90% gasoline

c) 40% ethanol + 60% gasoline

d) 50% ethanol + 50% gasoline

Answer: b

Explanation: 10% ethanol + 90% gasoline makes gashol.

3. Stoichiometric air-fuel ratio of alcohol when compared to gasoline is?

a) higher

b) lower

c) equal

d) none of the mentioned

Answer: b

Explanation: None.

4. Small amount of gasoline is added to alcohol to ___________

a) reduce the emission

b) to increase the power output

c) to increase the efficiency

d) to improve cold weather starting

Answer: d

Explanation: None.

5. Methanol by itself is not a good CI engine fuel because ___________

a) its octane number is high

b) its cetane number is low

c) all of the mentioned

d) none of the mentioned

Answer: c

Explanation: None.

6. Anti-knock characteristics of alcohol when compared to gasoline is?

a) higher

b) lower

c) equal

d) none of the mentioned

Answer: a

Explanation: Anti-knock characteristics of alcohol when compared to gasoline is higher and stoichiometric air-fuel ratio of alcohol when compared to gasoline is generally lower.

7. Alcohols alone cannot be used in CI engines as ___________

a) their self ignition temperature is high

b) latent heat of vaporization is high

c) all of the mentioned

d) none of the mentioned

Answer: c

Explanation: None.

8. The compression ratio of alcohol fuel lies between ___________

a) 11:1 to 13:1

b) 7:1 to 9:1

c) 5:1 to 7:1

d) none of the mentioned

Answer: a

Explanation: None.

9. The calorific value of alcohols is _____________ in diesel oil.

a) higher than

b) lower than

c) same

d) none of the mentioned

Answer: b

Explanation: None.

10. Which is the effective inhibitor of pre-ignition?

a) alcohol

b) water

c) lead

d) none of the mentioned

Answer: b

Explanation: The effective inhibitor of pre-ignition is water and not alcohol or lead.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Gaseous Fuels”.

1. Gaseous fuel is most suited for IC engine since the physical delay is almost ___________

a) zero

b) more

c) less

d) none of the mentioned

Answer: a

Explanation: As compared to other fuels there is almost no delay in gaseous fuel and for this purpose, it is preferred the most.

2. What is the advantage of hydrogen as an IC engine fuel?

a) high volumetric efficiency

b) low fuel cost

c) no HC and CO emissions

d) none of the mentioned

Answer: c

Explanation: The main advantage of hydrogen as an IC engine fuel is that there are no HC and CO emissions.

3. What is the disadvantage of hydrogen as a fuel in an IC engine?

a) storage is safe

b) low NO x

c) detonating tendency

d) easy handling

Answer: c

Explanation: None.

4. Which is the major constituent of natural gas?

a) ethane

b) methane

c) butane

d) propane

Answer: b

Explanation: Only methane is the major constituent of natural gas.

5. What is the octane of natural gas?

a) 60-80

b) 80-100

c) >100

d) <60

Answer: c

Explanation: The octane number of natural gas is always > 100.

6. What is the major disadvantage of LPG as fuel in automobiles?

a) reduction in life of engine

b) less power compared to gasoline

c) reduction in life of engine & less power compared to gasoline

d) none of the mentioned

Answer: c

Explanation: None.

7. Hydrogen gas has ______________ self-ignition temperature.

a) very low

b) very high

c) no

d) none of the mentioned

Answer: b

Explanation: None.

8. The energy content of air hydrogen mixture is _________ than liquid hydrocarbon fuels.

a) lower

b) higher

c) negligible

d) none of the mentioned

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Hydrogen Engine”.

1. Hydrogen has very ______________ density both as gas and as liquid.

a) high

b) low

c) equal

d) none of the mentioned

Answer: b

Explanation: In both gas and in liquid form, hydrogen has very low density.

2. Hydrogen engine operate on ____________ throttling.

a) very little

b) very high

c) without

d) none of the mentioned

Answer: b

Explanation: Very high throttling is required in a hydrogen engine operation.

3. The power output of hydrogen engine is limited by ___________

a) detonation and knocking

b) pre-ignition and back flash

c) pre-ignition and detonation

d) none of the mentioned

Answer: b

Explanation: The power output of the hydrogen engine is limited by pre-ignition and back flash because detonation and knocking do not occur in the hydrogen engine.

4. Hydrogen gas has less than _______________ the density of air.

a) 1/12th

b) 1/10th

c) 2/3rd

d) 1/3rd

Answer: b

Explanation: None.

5. The heating value per unit volume of hydrogen gas is less than ______________ that of air.

a) 1/12th

b) 1/10th

c) 2/3rd

d) 1/3rd

Answer: d

Explanation: None.

6. Hydrogen can be used in S.I. engines by ___________

a) manifold induction

b) direct introduction of hydrogen into the cylinder

c) supplementing gasoline

d) all of the mentioned

Answer: d

Explanation: None.

7. Hydrogen is _____________ reactive fuel.

a) highly

b) non

c) less

d) none of the mentioned

Answer: a

Explanation: None.

8. Natural gas obtained from oil wells is known as ___________

a) dry gas

b) wet gas

c) casing head gas

d) none of the mentioned

Answer: c

Explanation: Another name for natural gas obtained from oil wells is casing head gas.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Dual Fuel Operations”.

1. The normal heptane(C 7 H 16 ) is given a rating of ____________ octane number.

a) 0

b) 50

c) 100

d) 120

Answer: a

Explanation: None.

2. A fuel of an octane number rating of 75 matches in knocking intensity as a mixture of ___________

a) 75% iso-octane and 25% normal heptane

b) 75% normal heptane and 25% iso-octane

c) 75% petrol and 25% diesel

d) 75% diesel and 25% petrol

Answer: a

Explanation: None.

3. What are the two reference fuels used for cetane rating?

a) cetane and iso-octane

b) cetane and alpha-methyl naphthalene

c) cetane and normal heptane

d) none of the mentioned

Answer: b

Explanation: Cetane and alpha-methyl naphthalene are the reference fuels taken for cetane rating.

4. A mixture containing 65% of iso-octane and 35% of normal heptane will have ___________

a) cetane number 65

b) octane number 65

c) cetane number 35

d) octane number 35

Answer: b

Explanation: A mixture containing 65% of iso-octane and 35% of normal heptane will have octane number 65 as octane number is the number percentage containing iso-octane.

5. A fuel of cetane number 40 has the same ignition quality as a mixture of ___________

a) 40% cetane and 60% alpha methyl naphthalene

b) 40% alpha methyl naphthalene and 60% cetane

c) 40% petrol and 60% diesel

d) 40% diesel and 60% petrol

Answer: a

Explanation: A fuel of cetane number 40 has the same ignition quality as a mixture of 40% cetane and 60% alpha methyl naphthalene as cetane number is counted on cetane percentage.

6. Which of the following is the anti-knock for compression ignition engines?

a) naphthene

b) tetra ethyl lead

c) amyl nitrate

d) hexadecane

Answer: c

Explanation: Amyl nitrate is the anti-knock for compression ignition engines.

7. The fuels in order of decreasing knock tendency for spark ignition engines are ___________

a) paraffins, aromatics, naphthenes

b) paraffins, naphthenes, aromatics

c) naphthenes, aromatics, paraffins

d) none of the mentioned

Answer: b

Explanation: Paraffins have the highest knocking tendency, while naphthenes have less knocking than paraffins and aromatics have the lowest knocking tendency.

8. Which of the following fuel has little tendency towards detonation?

a) Benzene

b) Iso-octane

c) Normal heptane

d) Alcohol

Answer: b

Explanation: Benzene has little tendency towards detonation.

9. Which of the following fuel detonates readily?

a) Benzene

b) Iso-octane

c) Normal heptane

d) Alcohol

Answer: c

Explanation: Normal heptane detonates readily.

10. The knocking tendency in spark ignition engines can be decreased by adding dopes like tetra ethyl lead and ethylene dibromide.

a) True

b) False

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Carburetion”.

1. A carburetor is used to supply _____________

a) petrol, air and lubricating oil

b) air and diesel

c) petrol and lubricating oil

d) petrol and air

Answer: d

Explanation: The purpose of the carburetor is to supply petrol and air.

2. The compensating jet in a carburetor supplies an almost constant amount of petrol at all speeds because the ____________

a) jet area is automatically varied depending on the suction

b) the flow from the main jet is diverted to the compensating jet with an increase in speed

c) the diameter of the jet is constant and the discharge coefficient is invariant

d) flow is produced due to the static head in the float chamber

Answer: d

Explanation: None.

3. Which of the following does not relate to spark ignition engine?

a) Ignition coil

b) Spark plug

c) Carburetor

d) Fuel injector

Answer: d

Explanation: Fuel injector is not related to spark ignition engine as there is no fuel injection in spark ignition engine.

4. Which of the following does not relate to a compression ignition engine?

a) Fuel pump

b) Fuel injector

c) Governor

d) Carburetor

Answer: d

Explanation: Carburetor is not related to compression ignition engine.

5. In carburetors, the top of the fuel jet with reference to the level in the float chamber is kept at ____________

a) same level

b) slightly higher level

c) slightly lower level

d) may be anywhere

Answer: b

Explanation: None.

6. Carburetion is done to ____________

a) feed petrol into cylinder

b) govern the engine

c) break up and mix the petrol with air

d) none of the mentioned

Answer: c

Explanation: The purpose of carburetion is to break up and mix the petrol with air.

7. Power impulses from IC engine are smoothed out by ____________

a) governor

b) crank shaft

c) gear box

d) flywheel

Answer: d

Explanation: Power impulses from IC engine are smoothed out by flywheel as the energy is stored in the flywheel.

8. Which of the following type of carburetor is preferred?

a) concentric type

b) eccentric type

c) horizontal type

d) vertical type

Answer: a

Explanation: Concentric type of carburetor is preferred as it gives a better fuel ratio.

9. In the passenger cars, which of the following type of carburetor is preferred?

a) horizontal type

b) downward draught type

c) upward draught type

d) none of the mentioned

Answer: b

Explanation: In the passenger cars, a downward draught type of carburetor is preferred to meet the load fuel ratio.

10. What is the part load efficiency of a carburetor?

a) maximum

b) optimum

c) poor

d) constant

Answer: c

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Air Fuel Mixtures”.

1. Air injected in IC engines refers to injection of ____________

a) air only

b) liquid fuel only

c) liquid fuel and air

d) none of the mentioned

Answer: c

Explanation: Liquid fuel and air are injected in IC engines.

2. The m.e.p. of a petrol engine first increases as the fuel air ratio is increased and then decreases on further increase in fuel air ratio. The m.e.p. is maximum in the zone of ____________

a) lean mixture

b) chemically correct mixture

c) rich mixture

d) none of the mentioned

Answer: c

Explanation: The m.e.p. is maximum in the zone of rich mixture.

3. The specific fuel consumption for a petrol engine first decreases with increase in fuel air ratio and then increases with further increase in air fuel ratio. The maximum value occurs in the range of ____________

a) lean mixture

b) chemically correct mixture

c) rich mixture

d) none of the mentioned

Answer: a

Explanation: The maximum value occurs in the range of lean mixture.

4. Auto-ignition reaction time for petrol engine first decreases with increase in fuel air ratio, reaches a minimum value and then increases with subsequent increase in fuel air ratio. The maximum value occurs in the region of ____________

a) lean mixture

b) chemically correct mixture

c) rich mixture

d) none of the mentioned

Answer: b

Explanation: The maximum value occurs in the region of chemically correct mixture.

5. Which is the most effective air cleaner in the case of diesel engines?

a) dry type

b) wet type

c) whirl type

d) oil bath type

Answer: d

Explanation: Oil bath type is the most effective air cleaner in case of diesel engines.

6. A high flame speed is obtained in diesel engine when air fuel ratio is ____________

a) uniform throughout the mixture

b) chemically correct mixture

c) about 3-5% rich mixture

d) about 10% rich mixture

Answer: d

Explanation: When air fuel ratio is about 10% rich mixture, then a high flame speed is obtained in diesel engine.

7. During idling, a petrol engine requires ______________ mixture.

a) lean

b) rich

c) chemically correct

d) none of the mentioned

Answer: b

Explanation: Rich mixture is required by a petrol engine when it is in idling condition.

8. The ___________ engines can work on very lean mixture of fuel.

a) spark ignition

b) compression ignition

c) spark & compression ignition

d) none of the mentioned

Answer: b

Explanation: Only the compression ignition engines can work on very lean mixture of fuel while spark ignition requires a richer mixture.

9. In order to mix air and petrol in the required proportion and to supply it to the engine during suction stroke, then ______________ is employed.

a) fuel pump

b) injector

c) carburetor

d) none of the mentioned

Answer: c

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Automotive Engines”.

1. For idling condition in automotive engines, the air-fuel mixture must be ______________

a) lean

b) rich

c) chemically balanced

d) none of the mentioned

Answer: b

Explanation: Generally, for idling condition in automotive engines, the air-fuel mixture must be a rich mixture and for cruising condition in automotive engines, the air-fuel mixture must be a lean mixture.

2. For cruising condition in automotive engines, the air-fuel mixture must be ___________

a) lean

b) rich

c) chemically balanced

d) none of the mentioned

Answer: a

Explanation: For cruising condition in automotive engines, the air-fuel mixture must be a lean mixture and for idling condition in automotive engines, the air-fuel mixture must be a rich mixture.

3. For high power condition in automotive engines, the air-fuel mixture must be ___________

a) lean

b) rich

c) chemically balanced

d) none of the mentioned

Answer: b

Explanation: For high power condition in automotive engines, the air-fuel mixture must be a rich mixture while for cruising condition in automotive engines, the air-fuel mixture must be a lean mixture and for idling condition in automotive engines, the air-fuel mixture must be a rich mixture.

4. To prevent overheating of exhaust valve and the area near it, the air-fuel mixture must be ___________

a) lean

b) rich

c) chemically balanced

d) none of the mentioned

Answer: b

Explanation: None.

5. In an automobile engine, the indication of knocking is available in the form of ___________

a) light

b) gas

c) audible sound

d) none of the mentioned

Answer: c

Explanation: Generally, in an automobile engine, indication of knocking is available in the form of audible sound.

6. The operator can make the engine operating conditions less stringent by ___________

a) jamming the throttle

b) releasing the throttle

c) engaging the throttle

d) none of the mentioned

Answer: b

Explanation: None.

7. When the throttle is suddenly opened, the mixture from the simple carburetor tends to become ___________

a) rich

b) lean

c) stoichiometric

d) not affected

Answer: b

Explanation: Generally, when the throttle is suddenly opened, the mixture from the simple carburetor tends to become lean.

8. Which of the following is a Precise petrol injection system?

a) direct injection

b) sequential injection

c) throttle body injection

d) port injection

Answer: c

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Principles Of Carburetion”.

1. A simple carburetor supplies a rich mixture during ___________

a) starting

b) idling

c) cruising

d) accelerating

Answer: d

Explanation: None.

2. The size of a carburetor is generally given in terms of the diameter of the ______________ in mm.

a) venturi tube

b) jet

c) nozzle

d) none of the mentioned

Answer: a

Explanation: The size of the carburetor is generally given in terms of the diameter of the venturi tube in mm.

3. A decrease in the density of air ______________ the value of air-fuel ratio.

a) increases

b) reduces

c) equals

d) none of the mentioned

Answer: b

Explanation: Generally, a decrease in the density of air reduces the value of air-fuel ratio.

4. Venturi tube is also known as ___________

a) choke tube

b) throat

c) nozzle

d) none of the mentioned

Answer: b

Explanation: None.

5. The pressure difference between the float chamber and the throat of the venturi is known as ___________

a) carburetor expansion

b) carburetor acceleration

c) carburetor depression

d) none of the mentioned

Answer: c

Explanation: Carburetor depression is defined as the pressure difference between the float chamber and the throat of the venturi.

6. The choke in an automobile meant is for supplying ___________

a) lean mixture

b) rich mixture

c) stoichiometric mixture

d) weak mixture

Answer: b

Explanation: None.

7. Modern carburettors provide the correct quality of air-fuel mixture during ___________

a) starting

b) idling

c) cruising

d) all of the mentioned

Answer: d

Explanation: Modern carburettors provide the correct quality of air-fuel mixture during all the conditions of starting, idling and cruising.

8. The air fuel ratio of the petrol engine is controlled by ___________

a) carburetor

b) injector

c) governor

d) none of the mentioned

Answer: a

Explanation: The air fuel ratio of the petrol engine is controlled by carburetor while the injector is used to inject fuel and governor is inside engine.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Parts Of Carburetor”.

1. To prevent blockage of the nozzle by dust particles, the gasoline is filtered by installing a ______________ at the inlet to the float chamber.

a) choke

b) fuel strainer

c) nozzle

d) none of the mentioned

Answer: b

Explanation: None.

2. The strainer consist of ___________

a) a fine wire mesh

b) cone shaped filtering device

c) cylindrical shaped filtering device

d) all of the mentioned

Answer: d

Explanation: The strainer may consist of a fine wire mesh or other types of filtering device, cone shaped or cylindrical shaped.

3. The function of a float chamber in a carburetor is to supply the fuel to the nozzle at a ___________

a) constant volume head

b) constant pressure head

c) variable pressure head

d) none of the mentioned

Answer: b

Explanation: The function of a float chamber in a carburetor is to supply the fuel to the nozzle at a constant pressure head and not at constant volume or variable pressure.

4. The main metering system of the carburetor controls the fuel feed for ___________

a) cruising

b) full throttle operations

c) all of the mentioned

d) none of the mentioned

Answer: c

Explanation: None.

5. The main metering system of the carburetor consists of ___________

a) the fuel metering orifice through which fuel is drawn from the float chamber

b) the main discharge

c) the passage leading to the idling system

d) all of the mentioned

Answer: d

Explanation: None.

6. What is the functions of the main metering system?

a) to proportion the fuel-air mixture

b) to decrease the pressure at the discharge nozzle exit

c) to limit the air flow at full throttle

d) all of the mentioned

Answer: d

Explanation: None.

7. The throttle regulates the output of the engine by ________________ the quantity of charge going into the cylinder.

a) constant regulating

b) varying

c) increasing

d) none of the mentioned

Answer: b

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Compensating Devices”.

1. On city roads one may be able to operate the vehicle between ________________ of the throttle only.

a) 30 to 70%

b) 40 to 80%

c) 25 to 60%

d) 25 to 50%

Answer: c

Explanation: Generally, on city roads, one may be able to operate the vehicle between 25 to 60% of the throttle only.

2. What is the principle of compensating jet device is to make the mixture?

a) leaner

b) equal

c) richer

d) none of the mentioned

Answer: a

Explanation: The principle of compensating jet device is to make the mixture leaner as the throttle opens progressively.

3. The compensating well is supplied with fuel from the main float chamber through a ___________

a) nozzle

b) restricting orifice

c) injector

d) none of the mentioned

Answer: b

Explanation: None.

4. The main metering jet is kept at a level of about _______________ below the fuel level in the float chamber.

a) 25 mm

b) 30 mm

c) 35 mm

d) 40 mm

Answer: a

Explanation: None.

5. Back suction control mechanism, is employed in ___________

a) small carburetors

b) medium carburetors

c) large carburetors

d) none of the mentioned

Answer: c

Explanation: Back suction control mechanism, is employed only in large carburetors.

6. Auxiliary ports are used for aircraft carburetors to compensate for the _____________ in density of air at high altitudes.

a) increase

b) stable

c) loss

d) none of the mentioned

Answer: c

Explanation: For practical purposes, the auxiliary ports are used for aircraft carburetors to compensate for the loss in density of air at high altitudes.

7. In the back suction control mechanism, if the valve is closed, the float chamber pressure will ____________ the pressure at the venturi throat.

a) equalize with

b) increase

c) decrease

d) none of the mentioned

Answer: a

Explanation: Generally, in the back suction control mechanism, if the valve is closed, the float chamber pressure will equalize with the pressure at the venturi throat and no fuel can flow.

8. Which of the following are compensating devices?

a) air-bleed jet

b) compensating jet

c) emulsion tube

d) all of the mentioned

Answer: d

Explanation: The compensating devices are air-bleed jet, compensating jet, emulsion tube, back suction control mechanism, auxiliary air valve and auxiliary air port.

9. Which of the following are compensating devices?

a) back suction control mechanism

b) auxiliary air valve

c) auxiliary air port

d) all of the mentioned

Answer: d

Explanation: Same as above.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Systems In Modern Carburetors”.

1. An SI engine sometimes continues to run for a very small period even after the ignition is switched off. This phenomenon is called?

a) idling

b) dieseling

c) throttling

d) none of the mentioned

Answer: b

Explanation: Dieseling is the phenomenon in which an SI engine sometimes continues to run for a very small period even after the ignition is switched off.

2. Dieseling may take place due to ___________

a) engine idling speed set to high

b) increase in compression ratio due to carbon deposits

c) inadequate or low octane rating

d) all of the mentioned

Answer: d

Explanation: Dieseling may take place due to engine idling speed set to high, increase in compression ratio due to carbon deposits, inadequate or low octane rating, engine overheating, too high spark plug heat range, incorrect adjustment of idle fuel-air mixture, sticking of throttle, requirement of tune up of engine and oil entry into the cylinder.

3. Dieseling may take place due to ___________

a) engine overheating

b) too high spark plug heat range

c) incorrect adjustment of idle fuel-air mixture

d) all of the mentioned

Answer: d

Explanation: Dieseling may take place due to engine idling speed set to high, increase in compression ratio due to carbon deposits, inadequate or low octane rating, engine overheating, too high spark plug heat range, incorrect adjustment of idle fuel-air mixture, sticking of throttle, requirement of tune up of engine and oil entry into the cylinder.

4. Dieseling may take place due to ___________

a) sticking of throttle

b) requirement of tune up of engine and oil entry into the cylinder

c) none of the mentioned

d) all of the mentioned

Answer: d

Explanation: Dieseling may take place due to engine idling speed set to high, increase in compression ratio due to carbon deposits, inadequate or low octane rating, engine overheating, too high spark plug heat range, incorrect adjustment of idle fuel-air mixture, sticking of throttle, requirement of tune up of engine and oil entry into the cylinder.

5. The solenoid valve operated idling circuit reduces ___________

a) engine performance

b) hydrocarbon emissions

c) co emissions

d) none of the mentioned

Answer: b

Explanation: None.

6. In order to accelerate the vehicle and consequently its engine, the mixture required is very ___________

a) rich

b) lean

c) thin

d) none of the mentioned

Answer: a

Explanation: Generally, in order to accelerate the vehicle and consequently its engine, the mixture required is very rich.

7. An economizer valve opens at ______________ throttle operation.

a) half

b) full

c) partial

d) none of the mentioned

Answer: b

Explanation: An economizer valve, generally opens at full throttle operation.

8. Economizer is also known as ___________

a) power enrichment system

b) power less system

c) power throttle system

d) none of the mentioned

Answer: a

Explanation: Another name for economizer is power enrichment system.

9. Economizer allows a large opening to the main jet when the throttle is ____________ beyond a specified limit.

a) closed

b) opened

c) partially opened

d) none of the mentioned

Answer: b

Explanation: None.

10. The metering rod used in an economizer ___________

a) is tapered

b) is not tapered

c) may be tapered

d) none of the mentioned

Answer: c

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Types Of Carburetors – 1”.

1. Carburetors are categorized depending upon ___________

a) direction of flow of air

b) direction of flow of fuel

c) direction of flow of air-fuel

d) none of the mentioned

Answer: a

Explanation: Generally, carburetors are categorized depending upon the direction of flow of air and not on fuel flow.

2. In updraught type carburetors, air enters at the ___________

a) center

b) top

c) bottom

d) none of the mentioned

Answer: c

Explanation: Generally, in updraught type carburetors, air enters at the bottom and leaves at the top.

3. In updraught type carburetors, air leaves at the ___________

a) center

b) top

c) bottom

d) none of the mentioned

Answer: b

Explanation: Generally, in updraught type carburetors, air leaves at the top and enters at the bottom.

4. In the constant choke carburetor, the air and fuel flow areas are always maintained to be ___________

a) constant

b) variable

c) linear

d) none of the mentioned

Answer: a

Explanation: Generally, in the constant choke carburetor, the air and fuel flow areas are always maintained to be constant.

5. In the constant choke carburetor, the pressure difference that causes flow of fuel and air is kept ___________

a) constant

b) variable

c) linear

d) none of the mentioned

Answer: b

Explanation: None.

6. Solex and Zenith carburetors are ___________

a) constant choke carburetors

b) constant vacuum carburetors

c) multiple venturi carburetors

d) multi jet carburetors

Answer: a

Explanation: None.

7. The constant vacuum carburetor is also known as ___________

a) constant choke carburetor

b) variable choke carburetor

c) multiple venturi carburetor

d) multi jet carburetor

Answer: b

Explanation: None.

8. In constant vacuum carburetor, air and fuel flow areas are maintained at a ____________ rate as per the demand on the engine.

a) constant

b) variable

c) linear

d) none of the mentioned

Answer: b

Explanation: None.

9. In constant vacuum carburetor, the vacuum is maintained at a ___________ rate.

a) constant

b) variable

c) linear

d) none of the mentioned

Answer: a

Explanation: In constant vacuum carburetor, the vacuum is maintained at a constant rate while air and fuel are maintained at a variable rate.

10. S.U and Carter carburetors are ___________

a) constant choke carburetors

b) constant vacuum carburetors

c) multiple venturi carburetors

d) multi jet carburetors

Answer: b

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Types Of Carburetors – 2”.

1. Multiple venturi system uses ____________ venturi.

a) single

b) multiple

c) double or triple

d) none of the mentioned

Answer: c

Explanation: Generally, a multiple venturi system uses double or triple venturi.

2. _____________ depression is created in the region of the fuel nozzle.

a) high

b) low

c) medium

d) none of the mentioned

Answer: a

Explanation: Generally, a high depression is created in the region of the fuel nozzle.

3. In multiple venturi system, the condensation of fuel is ___________

a) increased

b) kept constant

c) reduced

d) none of the mentioned

Answer: c

Explanation: None.

4. In the multiple venturi system, what is the speed system?

a) high

b) low

c) medium

d) none of the mentioned

Answer: a

Explanation: None.

5. A dual carburetor supplies ______________ quality charge of the mixture to the cylinders.

a) uniform

b) variable

c) linear

d) none of the mentioned

Answer: a

Explanation: For the practical purposes the dual carburetor supplies uniform quality charge of the mixture to the cylinders.

6. The volumetric efficiency of a dual carburetor is ________________ in a single barrel carburetor.

a) lower than

b) higher than

c) same as

d) none of the mentioned

Answer: b

Explanation: Generally, the volumetric efficiency of a dual carburetor is higher than in a single barrel carburetor.

7. Carburetors with two outlets connected to two intake manifolds are known as ___________

a) barrel

b) two throat carburetors

c) barrel & two throat carburetors

d) none of the mentioned

Answer: c

Explanation: Carburetors with two outlets connected to two intake manifolds are known as a barrel or two throat carburetors.

8. What are the important requirements of automobile carburetors?

a) ease of starting the engine, particularly under low ambient conditions

b) ability to give full power quickly after starting the engine

c) equally good and smooth engine operation at various loads

d) all of the mentioned

Answer: d

Explanation: The important requirements of automobile carburetors are

i) ease of starting the engine, particularly under low ambient conditions

ii) ability to give full power quickly after starting the engine

iii) equally good and smooth engine operation at various loads

iv) good and quick acceleration of the engine

v) developing sufficient power at high engine speeds

vi) simple and compact in construction

vii) good fuel economy

viii) absence of racing of the engine under idling conditions

ix) ensuring full torque at low speeds.

9. What are the important requirements of an automobile carburetor?

a) good and quick acceleration of the engine

b) developing sufficient power at high engine speeds

c) simple and compact in construction

d) all of the mentioned

Answer: d

Explanation: Same as above.

10. Which are the most important requirements of an automobile carburetor?

a) good fuel economy

b) absence of racing of the engine under idling conditions

c) ensuring full torque at low speeds.

d) all of the mentioned

Answer: d

Explanation: Same as above.

11. A soles carburetor has ___________

a) good ease of starting

b) good performance

c) reliability

d) all of the mentioned

Answer: d

Explanation: The solex carburetor is famous for its ease of starting, good performance and reliability.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Altitude Compensation”.

1. If the vehicle is operated at an altitude lower than calibration altitude __________________ mixture is obtained.

a) lean

b) rich

c) chemically equal

d) none of the mentioned

Answer: a

Explanation: If the vehicle is operated at an altitude lower than calibration altitude, generally, lean mixture is obtained.

2. At lower altitude, the vehicles result in _____________

a) hydrocarbon emission

b) carbon monoxide emission

c) poor drivability

d) none of the mentioned

Answer: c

Explanation: Generally, at lower altitudes the vehicles result in poor drivability while at higher altitudes the vehicles result in hydrocarbon and carbon monoxide emissions.

3. If the vehicle is operated at an altitude higher than calibration altitude ____________ mixture is obtained.

a) lean

b) rich

c) chemically equal

d) none of the mentioned

Answer: b

Explanation: If The vehicle is operated at an altitude higher than calibration altitude, generally, rich mixture is obtained.

4. At higher altitude, the vehicles result in _____________

a) hydrocarbon emission

b) carbon monoxide emission

c) hydrocarbon & carbon monoxide emission

d) none of the mentioned

Answer: c

Explanation: At higher altitudes the vehicles result in hydrocarbon and carbon monoxide emissions while at lower altitudes the vehicles result in poor drivability.

5. At higher altitude, power is _____________

a) increased

b) reduced

c) remains same

d) none of the mentioned

Answer: b

Explanation: None.

6. At higher altitude, the mixture strength delivered by the carburetor becomes richer at a rate ___________ proportional to the square root of the density ratio.

a) directly

b) inversely

c) unpredictable

d) none of the mentioned

Answer: b

Explanation: None.

7. At 6,000 m altitude, the air pressure is approximately ________________ the pressure at sea level.

a) same as

b) one-half

c) twice

d) none of the mentioned

Answer: b

Explanation: In practical at 6,000 m altitude, the air pressure is approximately one-half the pressure at sea level.

8. The __________________ type of mixture control system, reduces the effective suction on the metering system.

a) back suction

b) needle

c) air port

d) none of the mentioned

Answer: a

Explanation: The back suction type of mixture control system, reduces the effective suction on the metering system and the needle type of mixture control system, restricts the flow of fuel through the metering system.

9. The _________________ type of mixture control system, restricts the flow of fuel through the metering system.

a) back suction

b) needle

c) air port

d) none of the mentioned

Answer: b

Explanation: The needle type of mixture control system, restricts the flow of fuel through the metering system while the back suction type of mixture control system, reduces the effective suction on the metering system.

10. The ________________ type of mixture control system, allows additional air to enter the carburetor between the main discharge nozzle and the throttle valve.

a) back suction

b) needle

c) air port

d) none of the mentioned

Answer: c

Explanation: The air port type of mixture control system, allows additional air to enter the carburetor between the main discharge nozzle and the throttle valve whereas the needle type of mixture control system, restricts the flow of fuel through the metering system while the back suction type of mixture control system, reduces the effective suction on the metering system.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Injection Systems – 1”.

1. In a fuel-injection system, the amount of fuel delivered into the air stream going to the engine is controlled by a pump which forces the fuel under pressure.

a) True

b) False

Answer: a

Explanation: None.

2. What is the requirement met by the injection system?

a) Proper atomization of fuel into very fine droplets

b) Proper spray pattern to ensure rapid mixing of fuel and air

c) Uniform distribution of fuel droplets throughout the combustion chamber

d) All of the mentioned

Answer: d

Explanation: None.

3. In an air injection system __________ is forced into the cylinder by means of compressed air.

a) air

b) fuel

c) water

d) none of the mentioned

Answer: b

Explanation: In an air injection system, generally fuel is forced into the cylinder by means of compressed air.

4. Fuel injector is used for __________

a) Gas engines

b) CI engines

c) SI engines

d) None of the mentioned

Answer: b

Explanation: Fuel injector is used for CI engines and not for SI engine and gas engines.

5. What is the advantage of an air injection system?

a) cheaper fuels can be used

b) mep is high

c) fine atomization and distribution of the fuel

d) all of the mentioned

Answer: d

Explanation: None.

6. Which of the following is a commonly used injection system in automobiles?

a) air injection

b) solid injection

c) combination of air and solid injection

d) none of the mentioned

Answer: b

Explanation: None.

7. Fuel injection pressure in solid injection system is around ______________

a) < 10 bar

b) 10-20 bar

c) 30-50 bar

d) 200-250 bar

Answer: d

Explanation: None.

8. Fuel filters do not use generally ___________

a) oil

b) paper

c) cloth

d) felt

Answer: b

Explanation: Generally paper is not used as fuel filters.

9. Fuel is injected in a four-stroke CI engine ___________

a) at the end of suction stroke

b) at the end of expansion stroke

c) at the end of compression stroke

d) at the end of exhaust stroke

Answer: c

Explanation: None.

10. What is the advantage of fuel injection in an SI engine?

a) low initial cost

b) low maintenance requirements

c) increased volumetric efficiency

d) none of the mentioned

Answer: c

Explanation: None.

11. A six cylinder, four-stroke diesel engine develops 125 kW at 3000 rpm. Its brake specific fuel consumption is 200gm/kW h. Calculate the quantity of fuel to be injected per cycle per cylinder. Specific gravity of the fuel may be taken as 0.85.

a) 0.0545 cc/cycle

b) 0.545 cc/ cycle

c) 5.45 cc/cycle

d) none of the mentioned

Answer: a

Explanation: Fuel consumed/hour = bsfc x Power output

= 200 x 10 -2 x 125 = 25 kg

Fuel consumption/cylinder = 25/6 = 4.17 kg/h

Fuel consumption/cycle = /n

where n = N/2 for four-stroke cycle engines = /

= 4.63 x 10 -5 kg

= 0.0463 gm

Volume of fuel injected = 0.0463/0.85

= 0.0545 cc/cycle.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Injection Systems – 2”.

1. Which of the following methods used on fuel injection?

a) air injection

b) mechanical injection

c) solid fuel injection

d) all of the mentioned

Answer: d

Explanation: The methods used on fuel injection are air injection, mechanical injection and solid fuel injection.

2. Removal of air from the pipeline is termed as ____________ in injection system.

a) bleeding

b) wound

c) sweating

d) none of the mentioned

Answer: a

Explanation: Generally, the removal of air from the pipeline is termed as bleeding in injection system.

3. What are the usual types of diesel injectors?

a) single hole injector

b) multi hole injector

c) long stem injector

d) all of the mentioned

Answer: d

Explanation: The types of diesel injectors are single hole injector, multi hole injector and long stem injector.

4. In pre-chamber and swirl type of combustion system ______________ is used.

a) single hole injector

b) multi hole injector

c) long stem injector

d) pintle nozzle

Answer: d

Explanation: In pre-chamber and swirl type of combustion system pintle nozzle is used and not the other nozzles.

5. _______________ is used to enable cold starting, with out the use of a heater plug.

a) Pintaux nozzle

b) Multi hole injector

c) Long stem injector

d) Pintle nozzle

Answer: a

Explanation: Generally, intaux nozzle is used to enable cold starting, with out the use of a heater plug.

6. If one or more nozzles are not spraying correctly then ________________ occurs.

a) dripping

b) misfiring

c) cold firing

d) none of the mentioned

Answer: b

Explanation: If one or more nozzles are not spraying correctly then misfiring occurs and not cold firing.

7. Solid injection is also called ________________

a) air injection

b) mechanical injection

c) compression fuel injection

d) none of the mentioned

Answer: b

Explanation: Generally, solid injection is also called mechanical injection.

8. Fuel is injected into the cylinder at the end of ______________ stroke.

a) suction

b) compression

c) expansion

d) exhaust

Answer: b

Explanation: Fuel is injected into the cylinder at the end of the compression stroke and not at suction or expansion stroke.

9. The beginning and end of the injection should be sharp.

a) True

b) False

Answer: a

Explanation: None.

10. In _____________ injection system only one pump is sufficient for multi-cylinder engine.

a) air

b) mechanical

c) compression fuel

d) common rail

Answer: d

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Injection Pump”.

1. The ___________ type injection pump consist of a reciprocating plunger inside a barrel.

a) jerk

b) distributer

c) jerk & distributer

d) none of the mentioned

Answer: a

Explanation: The jerk type injection pump consists of a reciprocating plunger inside a barrel and not a distributer.

2. The plunger of a jerk type pump is driven by a ___________

a) crankshaft

b) camshaft

c) pully

d) none of the mentioned

Answer: b

Explanation: Generally, the plunger of a jerk type pump is driven by a camshaft.

3. The axial distance traversed by the plunger is ____________ for every stroke.

a) same

b) different

c) unpredictable

d) none of the mentioned

Answer: a

Explanation: The axial distance traversed by the plunger is constant and hence same for every stroke.

4. Bosh fuel injection pump is an example of _______________ type fuel injector pump.

a) jerk

b) distributer

c) jerk & distributer

d) none of the mentioned

Answer: a

Explanation: Bosh fuel injection pump is an example of jerk type fuel injector pump and not distributer type.

5. In a _____________ type of injection pump, the fuel is distributed to each cylinder by means of a rotor.

a) jerk

b) distributer

c) jerk & distributer

d) none of the mentioned

Answer: b

Explanation: In a distributer type of injection pump, the fuel is distributed to each cylinder by means of a rotor while in a jerk type plunger is used.

6. What is the advantage of petrol injections?

a) higher power

b) free from icing trouble

c) higher power & free from icing trouble

d) none of the mentioned

Answer: c

Explanation: Both higher power and free from icing trouble are the advantages of a petrol injection system.

7. What is the disadvantage of petrol injection?

a) high initial cost

b) complicated design

c) high initial cost & complicated design

d) none of the mentioned

Answer: c

Explanation: Both high initial cost and complicated design are the disadvantages of a petrol injection system.

8. In the idle speed adjustment of the pneumatic governor, when the set-screw in the system is slightly screwed in _____________

a) the idling speed will be reduced

b) the idling speed will be increased

c) there will be no idling speed

d) none of the mentioned

Answer: b

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Injection Pump Governor”.

1. Fuel delivered by a pump increases with __________

a) pressure

b) speed

c) pressure & speed

d) none of the mentioned

Answer: b

Explanation: Rate of fuel injection is directly proportional to engine speed, so fuel delivered by a pump increases with speed.

2. Quantity of fuel delivered increases with load causing excessive ________________

a) carbon deposits

b) high exhaust temperature

c) carbon deposits & high exhaust temperature

d) none of the mentioned

Answer: c

Explanation: Quantity of fuel delivered increases with load causing excessive carbon deposits and high exhaust temperature.

3. When the engine speed tends to exceed the limit the _____________ fly apart.

a) weight

b) volume

c) weight & volume

d) none of the mentioned

Answer: a

Explanation: When the engine speed tends to exceed the limit the weight fly apart and not volume.

4. Lesser fuel causes the engine speed to ___________

a) remain constant

b) increase

c) decrease

d) none of the mentioned

Answer: c

Explanation: Fuel volume is directly proportional to speed, so lesser fuel causes the engine speed to decrease.

5. The purpose of a _____________ is to provide automatic control of the idling and maximum speeds to the engine.

a) governor

b) nozzle

c) throttle

d) none of the mentioned

Answer: a

Explanation: The purpose of a governor is to provide automatic control of the idling and maximum speeds to the engine and not of throttle or nozzle.

6. The driver’s foot accelerator controls the intermediate _____________ of the engine.

a) pressure

b) speed

c) pressure & speed

d) none of the mentioned

Answer: b

Explanation: Generally, the driver’s foot accelerator controls the intermediate speed of the engine.

7. In a _____________ governor, the camshaft of the pump is fitted to two ball weights.

a) mechanical

b) pneumatic

c) mechanical & pneumatic

d) none of the mentioned

Answer: a

Explanation: None.

8. The _____________ governor functions due to the vacuum created by suction in the air inlet pipe of the engine.

a) mechanical

b) pneumatic

c) mechanical & pneumatic

d) none of the mentioned

Answer: b

Explanation: The pneumatic governor functions due to the vacuum created by suction in the air inlet pipe of the engine while in a mechanical governor, the camshaft of the pump is fitted to two ball weights.

9. In the _____________ governor, the induction part throttle is operated by the foot pedal accelerator.

a) mechanical

b) pneumatic

c) mechanical & pneumatic

d) none of the mentioned

Answer: b

Explanation: In the pneumatic governor, the induction part throttle is operated by the foot pedal accelerator while in a mechanical governor, the camshaft of the pump is fitted to two ball weights.

10. If the engine is at rest and the lever controlling the engine speed is released, the spring will force the control to reach its ______________ position.

a) maximum

b) minimum

c) center

d) none of the mentioned

Answer: a

Explanation: None.

11. When the mechanical governor is running on ‘no load’ position ___________

a) the ball weights fly

b) the ball weight do not fly

c) the speed increases

d) none of the mentioned

Answer: b

Explanation: Generally, when the mechanical governor is running on ‘no load’ position, the ball weight do not fly.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Fuel Injector”.

1. Quick and complete combustion is ensured by a well designed _____________

a) governor

b) fuel injector

c) throttle

d) none of the mentioned

Answer: a

Explanation: Generally, quick and complete combustion is ensured by a well designed fuel injector.

2. By atomizing the fuel into very fine droplets, it _____________ the surface area of the fuel droplets.

a) increases

b) decreases

c) unpredictable

d) none of the mentioned

Answer: a

Explanation: When the fuel is atomized into very fine droplets, it increases the surface area of the fuel droplets.

3. _____________ is done by forcing the fuel through a small orifice under high pressure.

a) Vacuum

b) Atomization

c) Carburation

d) None of the mentioned

Answer: b

Explanation: Generally, atomization is done by forcing the fuel through a small orifice under high pressure.

4. The injector assembly consists of ___________

a) a needle valve

b) a compression spring

c) a nozzle and an injector body

d) all of the mentioned

Answer: d

Explanation: The injector assembly consists of

i) a needle valve

ii) a compression spring

ii) a nozzle

iv) an injector body.

5. When the fuel is supplied by the injection pump, it exerts sufficient force against the spring to lift the ___________

a) nozzle valve

b) throttle valve

c) mechanical valve

d) none of the mentioned

Answer: a

Explanation: When the fuel is supplied by the injection pump, it exerts sufficient force against the spring to lift the nozzle valve as only through nozzle the fuel is sprayed.

6. _____________ is sprayed into the combustion chamber in a finely atomized particles.

a) Air

b) Fuel

c) Water

d) None of the mentioned

Answer: b

Explanation: Generally, fuel is sprayed into the combustion chamber in finely atomized particles.

7. The spring tension and the valve opening pressure is controlled by adjusting the screw provided at the ___________

a) top

b) bottom

c) center

d) none of the mentioned

Answer: a

Explanation: None.

8. For proper lubrication between the nozzle valve and its guide a small quantity of fuel is allowed to leak through the clearance.

a) True

b) False

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Nozzle”.

1. _____________ is that part of an injector through which the liquid fuel is sprayed into the combustion chamber.

a) Governor

b) Nozzle

c) Throttle

d) None of the mentioned

Answer: b

Explanation: Nozzle is that part of an injector through which the liquid fuel is sprayed into the combustion chamber while governor is a part used inside engine.

2. _____________ is the first phase in obtaining proper mixing of the fuel and air in the combustion chamber.

a) Vaporization

b) Atomization

c) Carburation

d) None of the mentioned

Answer: b

Explanation: Atomization is the first phase in obtaining proper mixing of the fuel and air in the combustion chamber whereas vaporization is the escaping of liquid.

3. _____________ the injection pressure better the dispersion and penetration of the fuel into all the desired locations in combustion chamber.

a) Higher

b) Lower

c) Equal

d) None of the mentioned

Answer: a

Explanation: None.

4. If the density of compressed air in the combustion chamber is ____________ then the resistance to the movement of the droplets is higher.

a) high

b) low

c) same

d) none of the mentioned

Answer: a

Explanation: When the density of compressed air in the combustion chamber is high then the resistance to the movement of the droplets is higher and dispersion of the fuel is better.

5. Fuel striking the walls of combustion chamber, decomposes and produces _____________ deposits.

a) iron

b) ash

c) carbon

d) none of the mentioned

Answer: c

Explanation: When the fuel strikes the walls of combustion chamber, decomposes and produces carbon deposits as it can only be decomposed in carbon and not in iron and ashes.

6. ___________ nozzle is used in open combustion chambers.

a) Single hole

b) Multi hole

c) Circumferential hole

d) None of the mentioned

Answer: c

Explanation: The circumferential hole nozzle is used in open type combustion chambers and single or multi hole nozzle are not used.

7. The size of the hole in a single hole nozzle is usually ___________

a) 0.2 mm

b) < 0.2 mm

c) > 0.2 mm

d) none of the mentioned

Answer: c

Explanation: The size of the hole in a single hole nozzle is usually less than 0.2 mm for better sprinkling of fuel.

8. In a single hole nozzle, the spray cone angle varies from ___________

a) 5 0 to 15 0

b) 10 0 to 15 0

c) 5 0 to 10 0

d) none of the mentioned

Answer: a

Explanation: The spray cone angle is usually in the range of 5 0 to 15 0 in a single hole nozzle.

9. The number of holes in a multi-hole nozzle, varies from ___________

a) 2 to 4

b) 4 to 18

c) 4 to 10

d) none of the mentioned

Answer: b

Explanation: The number of holes in a multi-hole nozzle, lies between 4 to 18 depending on the size and requirement of the engine.

10. The hole diameter in a multi-hole nozzle, lies between ___________

a) 0.25 to 0.35 mm

b) 0.20 to 0.30 mm

c) 0.30 to 0.40 mm

d) none of the mentioned

Answer: a

Explanation: The hole diameter in a multi-hole nozzle, lies between the range of 0.25 to 0.35 mm for the better fuel flow in the combustion chamber.

11. The hole angle in a multi-hole nozzle, lies between ___________

a) 10 0 to 15 0

b) 20 0 to 35 0

c) 20 0 to 45 0

d) none of the mentioned

Answer: c

Explanation: The the hole angle in a multi-hole nozzle, lies between 20 0 to 45 0 for better fuel combustion.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Fuel Injection In S.I. Engine”.

1. The injection of fuel into a SI engine can be done by ___________

a) direct injection of fuel into the cylinder

b) injection of fuel close to the inlet valve

c) injection of fuel into the inlet manifold

d) all of the mentioned

Answer: d

Explanation: The injection of fuel into a SI engine can be done by

i) direct injection of fuel into the cylinder

ii) injection of fuel close to the inlet valve

iii) injection of fuel into the inlet manifold.

2. _____________ injection is adopted when manifold injection is contemplated.

a) Continuous

b) Timed

c) Continuous & Timed

d) None of the mentioned

Answer: a

Explanation: When manifold injection is contemplated, generally, continuous injection is adopted.

3. In _____________ injection, fuel is injected only during induction stroke over a limited period.

a) continuous

b) timed

c) continuous & timed

d) none of the mentioned

Answer: b

Explanation: Generally, in timed injection, fuel is injected only during induction stroke over a limited period.

4. Fuel injection in an SI engine _____________ volumetric efficiency.

a) increases

b) decreases

c) maintains constant

d) none of the mentioned

Answer: a

Explanation: Generally, the fuel injection in an SI engine increases volumetric efficiency.

5. By using fuel injection in an SI engine, better _____________ efficiency is obtained.

a) thermal

b) mechanical

c) unpredictable

d) none of the mentioned

Answer: a

Explanation: Better thermal efficiency is obtained, by using fuel injection in an SI engine.

6. By using fuel injection in an SI engine, lower _____________ is obtained.

a) exhaust emission

b) thermal efficiency

c) unpredictable

d) none of the mentioned

Answer: a

Explanation: Lower exhaust emission is obtained by using fuel injection in an SI engine.

7. Which is the most accurate gasoline injection system?

a) direct injection

b) port injection

c) throttle body injection

d) manifold injection

Answer: b

Explanation: Of all the gasoline injection system, the most accurate gasoline injection system is port injection.

8. What is the advantage of fuel injection in an SI engine?

a) low initial cost

b) low maintenance requirements

c) increased volumetric efficiency

d) none of the mentioned

Answer: c

Explanation: The main advantage of fuel injection in SI engine is increased volumetric efficiency.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Gasoline Injection”.

1. Multi-point fuel injection system uses ____________

a) manifold injection

b) direct injection

c) port injection and throttle body injection

d) none of the mentioned

Answer: c

Explanation: Multi-point fuel injection system uses port injection and throttle body injection.

2. L-MPFI system uses ___________

a) port injection

b) direct injection

c) manifold injection

d) throttle body injection

Answer: a

Explanation: L-MPFI system uses port injection while multi-point fuel injection system uses port injection and throttle body injection while D-MPFI system uses direct injection.

3. D-MPFI system uses ___________

a) port injection

b) direct injection

c) manifold injection

d) throttle body injection

Answer: b

Explanation: D-MPFI system uses direct injection and L-MPFI system uses port injection while multi-point fuel injection system uses port injection and throttle body injection.

4. Common rail injection system uses injection pressures of the order ___________

a) 100-200 bar

b) 200-400 bar

c) 400-600 bar

d) 1500 bar

Answer: d

Explanation: Generally, the common rail injection system uses injection pressures of the order 1500 bar.

5. Continuous injection system usually has ___________

a) plunger pump

b) rotary pump

c) gear pump

d) vane pump

Answer: b

Explanation: In common use continuous injection system usually has rotary pump.

6. What is the cold start injector?

a) maintains stoichiometric air-fuel ratio

b) provides lean air-fuel ratio

c) it gives rich air-fuel ratio

d) none of the mentioned

Answer: c

Explanation: Generally, the cold start injector gives rich air-fuel ratio.

7. ECU is an electronic injection system used for ___________

a) calculating the appropriate injection timing

b) meeting only certain operating conditions

c) closing the injection valve only

d) none of the mentioned

Answer: a

Explanation: For calculating the appropriate injection timing, an electronic injection system called ECU is used.

8. With EFI of diesel engines ___________

a) sharp start and stop is not possible

b) very high injection pressure can be obtained

c) sudden cylinder cut-off is impossible

d) diagnostic properties are poor

Answer: b

Explanation: Generally, with EFI of diesel engines very high injection pressure can be obtained.

9. EFI system can achieve ___________

a) proper injection timing

b) proper injection quantity

c) proper injection pressure

d) all of the mentioned

Answer: d

Explanation: EFI system can achieve:

i) proper injection timing

ii) proper injection quantity

iii) proper injection pressure.

10. Gasoline engines are _____________ than diesel engines.

a) heavier

b) lighter

c) unpredictable

d) none of the mentioned

Answer: a

Explanation: In comparison to diesel engine, gasoline engines are heavier.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “IC Engine Questions and Answers – Electronic Injection System – 1”.

1. _____________ senor senses the amount of oxygen in the engine exhaust and calculates air-fuel ratio.

a) Engine temperature

b) Exhaust gas

c) Air flow

d) Air inlet temperature

Answer: b

Explanation: Exhaust gas senor senses the amount of oxygen in the engine exhaust and calculates air-fuel ratio while engine temperature sensor senses the temperature of the engine coolant, and from this data the computer adjusts the mixture strength to rich side for cold starting.

2. In _____________ sensor, output voltage changes in proportion to air-fuel ratio.

a) engine temperature

b) exhaust gas

c) air flow

d) air inlet temperature

Answer: b

Explanation: Only in exhaust gas sensor, output voltage changes in proportion to air-fuel ratio.

3. The _____________ sensor senses the temperature of the engine coolant, and from this data the computer adjusts the mixture strength to rich side for cold starting.

a) engine temperature

b) exhaust gas

c) air flow

d) air inlet temperature

Answer: a

Explanation: The engine temperature sensor senses the temperature of the engine coolant, and from this data the computer adjusts the mixture strength to rich side for cold starting while the air flow sensor, monitors mass or volume of air flowing into the intake manifold for adjusting the quantity of fuel and exhaust gas senor senses the amount of oxygen in the engine exhaust and calculates air-fuel ratio.

4. The _____________ sensor, monitors mass or volume of air flowing into the intake manifold for adjusting the quantity of fuel.

a) engine temperature

b) exhaust gas

c) air flow

d) air inlet temperature

Answer: c

Explanation: The air flow sensor, monitors mass or volume of air flowing into the intake manifold for adjusting the quantity of fuel while exhaust gas senor senses the amount of oxygen in the engine exhaust and calculates air-fuel ratio.

5. The _____________ sensor, checks the temperature of the ambient air entering the engine for fine tuning the mixture strength.

a) engine temperature

b) exhaust gas

c) air flow

d) air inlet temperature

Answer: d

Explanation: The air inlet temperature sensor, checks the temperature of the ambient air entering the engine for fine tuning the mixture strength whereas the engine temperature sensor senses the temperature of the engine coolant, and from this data the computer adjusts the mixture strength to rich side for cold starting while the air flow sensor, monitors mass or volume of air flowing into the intake manifold for adjusting the quantity of fuel and exhaust gas senor senses the amount of oxygen in the engine exhaust and calculates air-fuel ratio.

6. The _____________ sensor, senses the movement of the throttle plate so that the mixture flow can be adjusted for engine speed and acceleration.

a) throttle position

b) manifold pressure

c) camshaft position

d) knock

Answer: a

Explanation: The throttle position sensor, senses the movement of the throttle plate so that the mixture flow can be adjusted for engine speed and acceleration while the manifold pressure sensor, monitors vacuum in the engine intake manifold so that the mixture strength can be adjusted with changes in engine load and the camshaft position sensor, senses rotation of engine camshaft for speed and timing of injection.

7. The ___________ sensor, monitors vacuum in the engine intake manifold so that the mixture strength can be adjusted with changes in engine load.

a) throttle position

b) manifold pressure

c) camshaft position

d) knock

Answer: b

Explanation: The manifold pressure sensor, monitors vacuum in the engine intake manifold so that the mixture strength can be adjusted with changes in engine load and the camshaft position sensor, senses rotation of engine camshaft for speed and timing of injection.

8. The _____________ sensor, senses rotation of engine camshaft for speed and timing of injection.

a) throttle position

b) manifold pressure

c) camshaft position

d) knock

Answer: c

Explanation: The camshaft position sensor, senses rotation of engine camshaft for speed and timing of injection whereas the throttle position sensor, senses the movement of the throttle plate so that the mixture flow can be adjusted for engine speed and acceleration while the manifold pressure sensor, monitors vacuum in the engine intake manifold so that the mixture strength can be adjusted with changes in engine load.

9. The _____________ sensor, is a microphone type sensor that detects ping or pre-ignition noise so that the ignition timing can be retarded.

a) throttle position

b) manifold pressure

c) camshaft position

d) knock

Answer: d

Explanation: The knock sensor, is a microphone type sensor that detects ping or pre-ignition noise so that the ignition timing can be retarded while the camshaft position sensor, senses rotation of engine camshaft for speed and timing of injection whereas the throttle position sensor, senses the movement of the throttle plate so that the mixture flow can be adjusted for engine speed and acceleration while the manifold pressure sensor, monitors vacuum in the engine intake manifold so that the mixture strength can be adjusted with changes in engine load.

10. In electronic fuel injection, there is improvement in the _____________ efficiency due to comparatively less resistance in the intake manifolds which will cause less pressure losses.

a) mechanical

b) volumetric

c) overall

d) none of the mentioned

Answer: b

Explanation: In electronic fuel injection, there is an improvement only in the volumetric efficiency due to comparatively less resistance in the intake manifolds which will cause less pressure losses and no other efficiencies are hindered.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Electronic Injection System – 2”.

1. The electronic fuel injection, eliminates majority of carburettor pressure loses and almost eliminates the requirement of manifold heating.

a) True

b) False

Answer: a

Explanation: None.

2. Manifold _____________ is eliminated due to the fuel being injected into or close to the cylinder and need not flow through the manifold.

a) heating

b) wetting

c) cooling

d) none of the mentioned

Answer: b

Explanation: Generally, manifold wetting is eliminated due to the fuel being injected into or close to the cylinder and need not flow through the manifold and not heating or cooling.

3. _____________ of fuel is independent of cranking speed and therefore starting will be easier.

a) Ignition

b) Atomization

c) Condensation

d) None of the mentioned

Answer: b

Explanation: Atomization of fuel is independent of cranking speed and therefore starting will be easier and ignition and condensation are not related to cranking speed.

4. Better atomization and _____________ will make the engine less knock prone.

a) ignition

b) vapourization

c) condensation

d) none of the mentioned

Answer: b

Explanation: Engine knock is dependent on poor atomization and vapourization conditions, so better atomization and vapourization will make the engine less knock prone.

5. Formation of ice on the _____________ plate is eliminated in electronic fuel injection.

a) throttle

b) nozzle

c) engine

d) none of the mentioned

Answer: a

Explanation: Generally, the formation of ice on the throttle plate is eliminated in electronic fuel injection and not of nozzle.

6. In an electronic fuel injection, variation of air-fuel ratio is almost negligible even when the vehicle takes different positions like turning, moving on gradients, uneven roads, etc.

a) True

b) False

Answer: a

Explanation: None.

7. In an electronic fuel injection, position of the injection unit is critical.

a) True

b) False

Answer: b

Explanation: No, in fact, in electronic fuel injection, position of the injection unit is not so critical and thereby the height of the engine can be less.

8. In an electronic fuel injection, the maintenance cost is?

a) low

b) high

c) nil

d) none of the mentioned

Answer: b

Explanation: Generally, in electronic fuel injection, the maintenance cost is high.

9. In an electronic fuel injection, the servicing is very ___________

a) difficult

b) easy

c) nil

d) none of the mentioned

Answer: a

Explanation: The servicing is very difficult in electronic fuel injection.

10. In an electronic fuel injection, there is a possibility of malfunctioning of some sensors.

a) True

b) False

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Multi Point Fuel Injection System”.

1. The main purpose of the Multi-Point Fuel Injection system is to supply a proper ratio of gasoline and air to the cylinders.

a) True

b) False

Answer: a

Explanation: None.

2. In the port injection arrangement, the injector is placed on the side of the intake manifold near the intake port.

a) True

b) False

Answer: a

Explanation: None.

3. What are the types of Multi-Point Fuel Injection System?

a) port injection

b) throttle body injection

c) port & throttle body injection

d) none of the mentioned

Answer: c

Explanation: Types of Multi-Point Fuel Injection system are

i) port injection

ii) throttle body injection.

4. The Multi-Point Fuel Injection system can be functionally divided into _____________

a) electronic control system

b) fuel system

c) air induction system

d) all of the mentioned

Answer: c

Explanation: The Multi-Point Fuel Injection system can be functionally divided into the following three main components:

i) electronic control system

ii) fuel system

iii) air induction system.

5. In MPFI-Electronic Control System, the sensors that monitor intake air temperature, the oxygen, the water temperature, the starter signal and the throttle position send signals to the ECU.

a) True

b) False

Answer: a

Explanation: None.

6. In MPFI-Electronic Control System, the _____________ sensor sends information about the engine speed.

a) speed

b) ignition

c) air-flow

d) air-mass

Answer: b

Explanation: In MPFI-Electronic Control System, the ignition sensor sends information about the engine speed and not speed, air flow and air mass sensors.

7. In MPFI-Electronic system, at the time of starting, the cold start injector is operated by the cold start injector time switch.

a) True

b) False

Answer: b

Explanation: None.

8. In MPFI-Fuel system, the throttle receives signals from the ECU and inject the fuel into the intake manifold.

a) True

b) False

Answer: b

Explanation: None.

9. In MPFI-Air Induction System, the air cleaner, the air flow meter, the throttle body and the air valve supply a proper amount of air to the air intake chamber and intake manifold.

a) True

b) False

Answer: a

Explanation: None.

10. In MPFI-Fuel System, the quantity of air supplied is just what is necessary for complete combustion.

a) True

b) False

Answer: b

Explanation: None.

11. In D-MPFI system, the fuel metering is regulated by the engine speed and the amount of air that actually enters the engine.

a) True

b) False

Answer: b

Explanation: None.

12. In D-MPFI system, the vacuum in the intake manifold is first sensed.

a) True

b) False

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Electronic Control System”.

1. The ECU in the electronic control system, receives signals from the sensors and determines the opening time for the injectors land which also controls the injection volume.

a) True

b) False

Answer: a

Explanation: None.

2. When the engine is cold, the starting of the engine is usually not ___________

a) difficult

b) easy

c) all of the mentioned

d) none of the mentioned

Answer: b

Explanation: The starting of the engine is usually not easy when the engine is cold.

3. When a cold engine is started, it requires a _____________ mixture.

a) leaner

b) richer

c) chemically equal

d) none of the mentioned

Answer: b

Explanation: For starting a cold engine, generally a richer mixture is required.

4. The cold start injector is a type of solenoid valve to which power is supplied from a battery for the opening and closing of the valve inside, thus for injecting the fuel.

a) True

b) False

Answer: a

Explanation: None.

5. The duration of injection time is controlled by a timing switch.

a) True

b) False

Answer: a

Explanation: None.

6. The ignition switch is composed of a bi-metal element and an electric heater coil.

a) True

b) False

Answer: b

Explanation: No, but in fact, the timing switch is composed of a bi-metal element and an electric heater coil.

7. As the temperature is low, the _____________ valve speeds up the engine idle speed to fast idling.

a) nozzle

b) throttle

c) air

d) none of the mentioned

Answer: c

Explanation: At low temperature, the air valve speeds up the engine idle speed to fast idling and not the throttle or nozzle.

8. When the engine is cold, the _____________ plate will be in closed position.

a) nozzle

b) throttle

c) air

d) none of the mentioned

Answer: b

Explanation: Generally, when the engine is cold, the throttle plate will be in closed position and at low temperature, the air valve speeds up the engine idle speed to fast idling.

9. When the engine reaches the normal operating temperature, the valve closes completely and the air flow is cut-off from the _____________ valve.

a) nozzle

b) throttle

c) air

d) none of the mentioned

Answer: c

Explanation: Generally, when the engine reaches the normal operating temperature, the valve closes completely and the air flow is cut-off from the air valve.

10. A thermo wax valve operates depending on the temperature of the engine coolant.

a) True

b) False

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Injection Timing”.

1. The fuel is injected into the inlet manifold of each cylinder at _____________ timing.

a) same

b) different

c) unpredictable

d) none of the mentioned

Answer: b

Explanation: The injection of fuel into the inlet manifold of each cylinder is at different timing.

2. The timing at which the injection of the fuel takes place inside the inlet manifold is called _____________ timing.

a) injection

b) suction

c) combustion

d) none of the mentioned

Answer: a

Explanation: Injection timing is defined as the timing at which the injection of the fuel takes place inside the inlet manifold.

3. In _____________ cylinder, the piston moves up from BDC to TDC during the exhaust stroke.

a) one

b) two

c) three

d) four

Answer: a

Explanation: Only in one cylinder, the piston moves up from BDC to TDC during the exhaust stroke and not in two or three cylinder engines.

4. Just before the piston reaches TDC during exhaust stroke, injection of the fuel takes place into the inlet manifold of the cylinder at about 60º crankangle before TDC.

a) True

b) False

Answer: a

Explanation: Yes, just before the piston reaches TDC during exhaust stroke, injection of the fuel takes place into the inlet manifold of the cylinder at about 60º crankangle before TDC.

5. At the beginning of the compression stroke, intake valve opens and the air fuel mixture is sucked into the cylinder during the suction stroke.

a) True

b) False

Answer: b

Explanation: No, but at the beginning of the suction stroke, intake valve opens and the air fuel mixture is sucked into the cylinder during the suction stroke.

6. In the four cylinder engine, the ECU calculates the appropriate injection timing for each cylinder and the air fuel mixture is made available at each suction stroke.

a) True

b) False

Answer: a

Explanation: yes, in the four cylinder engine, the ECU calculates the appropriate injection timing for each cylinder and the air fuel mixture is made available at each suction stroke.

7. In order to meet the operating conditions, the injection valve is kept open for a longer time by ECU.

a) True

b) False

Answer: a

Explanation: Yes, in order to meet the operating conditions, the injection valve is kept open for a longer time by ECU.

8. In a common rail fuel injection system, injection pressure is dependent on engine speed.

a) True

b) False

Answer: b

Explanation: No, but in a common rail fuel injection system, injection pressure is independent of engine speed.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Group Gasoline Injection System – 1”.

1. In an engine having group gasoline injection system, the injectors are activated ___________

a) individually

b) in groups

c) both individually and in groups

d) none of the mentioned

Answer: b

Explanation: In an engine having group gasoline injection system, the injectors are not activated individually, but activated in groups.

2. For a group injection system, sensors are used for detecting _____________ in the manifold.

a) pressure

b) speed

c) coolant

d) none of the mentioned

Answer: a

Explanation: For a group injection system, sensors are used for detecting pressure in the manifold and not speed and coolant.

3. The timing of the injectors is decided by the engine speed sensor.

a) True

b) False

Answer: a

Explanation: Yes, the timing of the injectors is decided by the engine speed sensor.

4. In pilot ignition system, a large quantity of fuel is injected.

a) True

b) False

Answer: b

Explanation: No, but in the pilot ignition system, a small quantity of fuel is first injected and allowed to undergo the ignition delay and burn.

5. By using EFI systems, precise control of injection timing can be achieved.

a) True

b) False

Answer: a

Explanation: Yes, by using EFI systems, precise control of injection timing can be achieved.

6. By means of EFI systems one can achieve the precise control of ___________

a) fuel injection quality

b) injection rate during various stages of injection

c) injection pressure during injection

d) all of the mentioned

Answer: d

Explanation: By means of EFI systems one can achieve the precise control of

i) fuel injection quality

ii) injection rate during various stages of injection

iii) injection pressure during injection

iv) nozzle opening speed

v) pilot injection timing and its quantity.

7. By means of EFI systems one can achieve the precise control of ___________

a) nozzle opening speed

b) pilot injection timing and its quantity

c) all of the mentioned

d) none of the mentioned

Answer: c

Explanation: Same as Above.

8. By using EFI system we get ___________

a) very high injection pressure

b) sharp start and stop of injection

c) cylinder cut off

d) all of the mentioned

Answer: d

Explanation: By using EFI system we get,

i) very high injection pressure

ii) sharp start and stop of injection

iii) cylinder cut off

iv) diagnostic capability

v) turbocharger control

vi) two stage injection.

9. By using EFI system we get ___________

a) diagnostic capability

b) turbocharger control

c) two stage injection

d) all of the mentioned

Answer: d

Explanation: Same as Above.

10. What are the types of electronic diesel injection control?

a) electronically controlled injection pumps

b) electronically controlled unit injectors

c) common rail fuel injection system

d) all of the mentioned

Answer: d

Explanation: Types of electronic diesel injection control are :

i) electronically controlled injection pumps

ii) electronically controlled unit injectors

iii) common rail fuel injection system.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Group Gasoline Injection System – 2”.

1. The inputs used in electronically controlled diesel fuel injection systems are ____________

a) engine speed

b) crank shaft position

c) accelerator pedal position

d) all of the mentioned

Answer: d

Explanation: The inputs used in electronically controlled diesel fuel injection systems are :

i) engine speed

ii) crank shaft position

iii) accelerator pedal position

iv) intake air temperature

v) lubricating oil temperature

vi) ambient air temperature

vii) turbocharger boost pressure

viii) intake air mass flow rate.

2. The inputs used in electronically controlled diesel fuel injection systems are _____________

a) intake air temperature

b) lubricating oil temperature

c) ambient air temperature

d) all of the mentioned

Answer: d

Explanation: Same as above.

3. The inputs used in electronically controlled diesel fuel injection systems are _____________

a) turbocharger boost pressure

b) intake air mass flow rate

c) turbocharger boost pressure & intake air mass flow rate

d) none of the mentioned

Answer: c

Explanation: Same as above.

4. The frequency of injection depends on the engine speed and number of cylinders.

a) True

b) False

Answer: a

Explanation: Yes, of course, the frequency of injection depends on the engine speed and number of cylinders.

5. The timing of injection has to be advanced as the speed _____________

a) decreases

b) increases

c) stables

d) none of the mentioned

Answer: b

Explanation: The timing of injection is directly dependent on engine speed, so it has to be advanced as the speed increases.

6. The lubricating oil and coolant temperatures does not indicate the engine condition.

a) True

b) False

Answer: b

Explanation: In fact, the lubricating oil and coolant temperatures indicate the engine condition.

7. The turbocharger boost pressure can not be used to detect the mass flow rate of air, which can be used to decide the fuel injection quantity.

a) True

b) False

Answer: b

Explanation: Actually, the turbocharger boost pressure is used to detect the mass flow rate of air, which can be used to decide the fuel injection quantity.

8. The ECU generates the pulses to operate the solenoid controlled spill valve.

a) True

b) False

Answer: a

Explanation: Yes, the ECU generates the pulses to operate the solenoid controlled spill valve.

9. The end of injection in the conventional inline element is determined by the instant when the top of the plunger covers the bypass or the spill ports.

a) True

b) False

Answer: b

Explanation: No, in fact the start of injection in the conventional inline element is determined by the instant when the top of the plunger covers the bypass or the spill ports.

10. The end of delivery occurs when the helical slot or groove on the plunger uncovers the ports.

a) True

b) False

Answer: a

Explanation: Yes, the end of delivery occurs when the helical slot or groove on the plunger uncovers the ports.

11. In common rail fuel injection system, very high injection pressures of order of _________ bar.

a) 1000

b) 1500

c) 2000

d) none of the mentioned

Answer: b

Explanation: Generally, in a common rail fuel injection system, very high injection pressures of order of 1500 bar.

12. In a common rail fuel injection system, there is complete control over start and end of injection.

a) True

b) False

Answer: a

Explanation: Yes, in a common rail fuel injection system, there is complete control over start and end of injection.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Requirements Of Ignition System”.

1. The function of the ignition system is to _____________ the flame propagation process.

a) stop

b) initiate

c) balance

d) none of the mentioned

Answer: b

Explanation: None.

2. The total enthalpy required to cause the flame to be self sustaining and promote ignition, is given by the product of the surface area of the spherical flame and the enthalpy per unit area.

a) True

b) False

Answer: a

Explanation: None.

3. A spark can be caused by applying a sufficiently low voltage between two electrodes separated by a gap.

a) True

b) False

Answer: b

Explanation: In fact, a spark can be caused by applying a sufficiently high voltage between two electrodes separated by a gap.

4. An ignition process obeys the law of ______________

a) conservation of mass

b) conservation of energy

c) conservation of momentum

d) none of the mentioned

Answer: b

Explanation: An ignition process obeys the law of conservation of energy as energy is only produced there.

5. The pressure, temperature and density of the mixture between the spark plug electrodes have a considerable influence on the __________ required to produce a spark.

a) voltage

b) current

c) mass

d) none of the mentioned

Answer: a

Explanation: The pressure, temperature and density of the mixture between the spark plug electrodes have a considerable influence on the voltage required to produce a spark and mass and current are dependent on voltage.

6. If the spark energy exceeds 40 mJ and the duration is longer than 0.5 ms, reliable ignition is obtained.

a) True

b) False

Answer: a

Explanation: None.

7. If the resistance of the deposits on the spark plug electrodes is sufficiently high, the loss of electrical energy through these deposits may prevent the spark discharge.

a) True

b) False

Answer: a

Explanation: None.

8. As air is poor conductor of electricity an air gap in an electric circuit acts as a high _____________

a) conductor

b) resistance

c) ignition

d) none of the mentioned

Answer: b

Explanation: As air is poor conductor of electricity, due to this an air gap in an electric circuit acts as a high resistance and conductor and ignition are required before conduction.

9. A spark is produced to ignite a homogeneous air fuel mixture in the combustion chamber of an engine, it is called spark ignition system.

a) True

b) False

Answer: a

Explanation: None.

10. An ignition system should provide a good spark between the _____________ of the plugs at the correct timing.

a) cathodes

b) anodes

c) electrodes

d) none of the mentioned

Answer: c

Explanation: An ignition system should provide a good spark between the electrodes of the plugs at the correct timing as only electrodes are used in ignition system and cathodes and anodes are used in battery.

11. An ignition system should function efficiently over the entire range of engine speed.

a) True

b) False

Answer: a

Explanation: None.

12. An ignition system should be heavy, effective and reliable in service.

a) True

b) False

Answer: b

Explanation: Actually, an ignition system should be light, effective and reliable in service.

13. An ignition system should be compact and easy to maintain.

a) True

b) False

Answer: a

Explanation: None.

14. An ignition system should be cheap and convenient to handle.

a) True

b) False

Answer: a

Explanation: None.

15. The interference from the low voltage source should not affect the functioning of the radio and television receivers inside an automobile.

a) True

b) False

Answer: b

Explanation: In fact, the interference from the high voltage source should not affect the functioning of the radio and television receivers inside an automobile.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Battery Ignition System”.

1. In battery ignition system, the energy required for producing spark is obtained from a _____________ battery.

a) 6 V to 12 V

b) 12 V to 24 V

c) 24 V to 30 V

d) none of the mentioned

Answer: a

Explanation: The battery used in vehicles are between 6 V to 12 V, so in battery ignition system, the energy required for producing spark is obtained from a 6 V to 12 V battery.

2. What are the essential components of a battery ignition system?

a) battery

b) ignition switch

c) ballast resistor

d) all of the mentioned

Answer: d

Explanation: The essential components of a battery ignition system are

i) battery

ii) ignition switch

iii) ballast resistor

iv) ignition coil

v) contact breaker

vi) capacitor

vii) distributor

viii) spark plug.

3. What are the essential components of a battery ignition system?

a) ignition coil

b) contact breaker

c) capacitor

d) all of the mentioned

Answer: d

Explanation: The essential components of a battery ignition system are

i) battery

ii) ignition switch

iii) ballast resistor

iv) ignition coil

v) contact breaker

vi) capacitor

vii) distributor

viii) spark plug.

4. What are the essential components of a battery ignition system?

a) distributor

b) spark plug

c) ballast resistor

d) all of the mentioned

Answer: d

Explanation: The essential components of a battery ignition system are

i) battery

ii) ignition switch

iii) ballast resistor

iv) ignition coil

v) contact breaker

vi) capacitor

vii) distributor

viii) spark plug.

5. The battery is charged by a __________ driven by the engine.

a) shaft

b) axle

c) dynamo

d) none of the mentioned

Answer: c

Explanation: The battery is charged by a dynamo driven by the engine and shaft and axle are not used in a battery.

6. A lead acid battery consists of a number of cells connected together in series and each having a nominal potential of 2 volts when fully charged.

a) True

b) False

Answer: a

Explanation: None.

7. The lead acid battery is used in ______________ duty commercial vehicles.

a) heavy

b) light

c) large

d) none of the mentioned

Answer: b

Explanation: The lead acid battery is used in light duty commercial vehicles while alkaline battery is used in heavy duty commercial vehicles.

8. The alkaline battery is used in ____________ duty commercial vehicles.

a) heavy

b) light

c) large

d) none of the mentioned

Answer: a

Explanation: The alkaline battery is used in heavy duty commercial vehicles while the lead acid battery is used in light duty commercial vehicles.

9. Battery is connected to the primary winding of the ignition coil through an ignition switch and blast resistor.

a) True

b) False

Answer: a

Explanation: None.

10. The ignition system can be turned ON or OFF, with the help of an ignition switch.

a) True

b) False

Answer: a

Explanation: None.

11. A blast resistor is provided in parallel with the primary winding to regulate the primary current.

a) True

b) False

Answer: b

Explanation: In fact, a blast resistor is provided in series with the primary winding to regulate the primary current.

12. An eight cylinder engine running at 3000 rpm requires __________ spark per minute.

a) 1000

b) 3000

c) 12000

d) none of the mentioned

Answer: c

Explanation: None.

13. The function of the distributor is to distribute the ignition surges to the individual spark plug in the correct sequence and at the correct instants in time.

a) True

b) False

Answer: a

Explanation: None.

14. When the ignition switch is opened, the primary winding of the coil is connected to the positive terminal post of the storage battery.

a) True

b) False

Answer: b

Explanation: When the ignition switch is closed, the primary winding of the coil is connected to the positive terminal post of the storage battery.

15. The primary voltage increases as the engine speed increases due to the limitations in the current switching capability of the breaker system.

a) True

b) False

Answer: b

Explanation: In fact, the primary voltage decreases as the engine speed increases due to the limitations in the current switching capability of the breaker system.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Magneto Ignition System – 1”.

1. In magneto ignition system, as the engine speed increases the flow of current ____________

a) decreases

b) remains constant

c) increases

d) none of the mentioned

Answer: c

Explanation: In the magneto ignition system, engine speed is directly proportional to current rate, so, as the engine speed increases the flow of current increases.

2. With magneto there is no starting difficulty.

a) True

b) False

Answer: b

Explanation: In fact, With magneto there is always a starting difficulty and sometimes a separate battery is needed for starting.

3. The magneto is best at high speeds and therefore is widely used for sports and racing cars, aircraft engines. etc.

a) True

b) False

Answer: a

Explanation: None.

4. In two wheelers magneto ignition system is favoured due to ____________ weight and less maintenance.

a) light

b) heavy

c) light & heavy

d) none of the mentioned

Answer: a

Explanation: The magneto ignition system is light weight and requires less maintenance due to which it is preferred in two wheelers.

5. The main advantage of the high tension magneto ignition system lies in the fact that the wirings carry a very high voltage and thus there is a strong possibility of causing engine misfire due to leakage.

a) True

b) False

Answer: b

Explanation: No, but the main disadvantage of the high tension magneto ignition system lies in the fact that the wirings carry a very high voltage and thus there is a strong possibility of causing engine misfire due to leakage.

6. Transistorized coil ignition system, reduces ignition system maintenance.

a) True

b) False

Answer: a

Explanation: None.

7. Transistorized coil ignition system, increases wear of the components.

a) True

b) False

Answer: b

Explanation: No, but in fact, a transistorized coil ignition system, reduces wear of the components.

8. Transistorized coil ignition system, decreases reliability.

a) True

b) False

Answer: b

Explanation: In fact, transistorized coil ignition system, increases reliability.

9. In transistorized coil ignition system, the life of spark plug is extended.

a) True

b) False

Answer: a

Explanation: None.

10. In transistorized coil ignition system, the ignition of lean mixtures is improved.

a) True

b) False

Answer: a

Explanation: None.

This set of IC Engine Interview Questions and Answers focuses on “Magneto Ignition System – 2”.

1. In SI engine, to obtain required firing order ___________

a) battery is installed

b) distributor is installed

c) carburettor is installed

d) ignition coil is installed

Answer: b

Explanation: In SI engine, to obtain required firing order distributor is installed and not battery or ignition coil.

2. What is the standard firing order in a four cylinder petrol engine?

a) 1-2-3-4

b) 1-4-3-2

c) 1-3-2-4

d) 1-3-4-2

Answer: d

Explanation: None.

3. Firing order is the order in which various cylinders of a multi cylinder engine fire.

a) True

b) False

Answer: a

Explanation: None.

4. The firing order is arranged to have power impulses equally spaced, and from the point of view of balancing.

a) True

b) False

Answer: a

Explanation: None.

5. The main function of a ___________ is to conduct the high potential from the ignition system into the combustion chamber.

a) spark plug

b) magneto ignition

c) battery

d) none of the mentioned

Answer: a

Explanation: The main function of a spark plug is to conduct the high potential from the ignition system into the combustion chamber while magneto ignition ignites with magnetic effect and battery provides electricity.

6. The spark plug must withstand pressures up to at least __________ bar.

a) 40

b) 50

c) 55

d) 60

Answer: c

Explanation: None.

7. A cold plug has a large heat transfer path and a large area exposed to the combustion gases or compared to hot plug.

a) True

b) False

Answer: b

Explanation: In fact, a cold plug has a short heat transfer path and a small area exposed to the combustion gases, or compared to hot plug.

8. In CDI system a capacitor is used to store the energy.

a) True

b) False

Answer: a

Explanation: In the CDI system a capacitor is used to store the energy, induction coil is not used.

9. In CDI system, the output voltage is relatively dependent of engine speed.

a) True

b) False

Answer: b

Explanation: Actually, in CDI system, the output voltage is relatively independent of engine speed.

10. Ignition timing is the correct instant for the introduction of spark near the end of compression stroke in the combustion chamber.

a) True

b) False

Answer: a

Explanation: None.

This set of IC Engine Interview Questions and Answers for freshers focuses on “Ignition Timing and Engine Parameters”.

1. If the engine is operating with richer mixtures the optimum spark timing must be _____________

a) constant

b) increased

c) retarded

d) none of the mentioned

Answer: c

Explanation: If the engine is operating with richer mixtures the optimum spark timing must be retarded as if the mixture is rich it has its low self ignition temperature.

2. Part load operation of a spark ignition engine is not affected by throttling the incoming charge.

a) True

b) False

Answer: b

Explanation: In fact, part load operation of a spark ignition engine is affected by throttling the incoming charge.

3. Due to throttling a smaller amount of charge enters the cylinder and the dilution due to residual gases is also greater.

a) True

b) False

Answer: a

Explanation: None.

4. Ignition delay does not depend upon the type of the fuel used in the engine.

a) True

b) False

Answer: b

Explanation: Actually, ignition delay will depend upon the type of the fuel used in the engine.

5. For maximum power and economy a slow burning fuel needs a higher spark advance than fast burning fuel.

a) True

b) False

Answer: a

Explanation: None.

6. The ignition timing is fixed to obtain minimum power from the engine.

a) True

b) False

Answer: b

Explanation: In fact, the ignition timing is fixed to obtain maximum power from the engine.

7. The ignition timing is affected by _____________

a) compression ratio

b) engine speed

c) mixture strength

d) all of the mentioned

Answer: d

Explanation: The ignition timing is affected by

i) compression ratio

ii) engine speed

iii) mixture strength

iv) combustion chamber design

v) throttle opening

vi) engine temperature

vii) type of fuel.

8. The ignition timing is affected by _____________

a) combustion chamber design

b) throttle opening

c) engine temperature

d) all of the mentioned

Answer: d

Explanation: The ignition timing is affected by

i) compression ratio

ii) engine speed

iii) mixture strength

iv) combustion chamber design

v) throttle opening

vi) engine temperature

vii) type of fuel.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Spark Advance Mechanism”.

1. The purpose of the spark advance mechanism is to assure that under every condition of engine operation, ignition takes place at the most favourable instant in time.

a) True

b) False

Answer: a

Explanation: None.

2. The engine speed and the engine load are the control quantities required for the automatic adjustment of the ignition timing.

a) True

b) False

Answer: a

Explanation: None.

3. The vacuum advance mechanism controls the ignition timing for full load operation.

a) True

b) False

Answer: b

Explanation: In fact, the centrifugal advance mechanism controls the ignition timing for full load operation.

4. Vacuum advance mechanism shifts the ignition point under ____________ load operation.

a) full

b) part

c) no

d) none of the mentioned

Answer: b

Explanation: None.

5. The vacuum advance mechanism operates depending on the centrifugal advance mechanism.

a) True

b) False

Answer: b

Explanation: Actually, the vacuum advance mechanism operates independent of the centrifugal advance mechanism.

6. The larger throttle opening means the possibility of better mixing and combustion during idling.

a) True

b) False

Answer: a

Explanation: None.

7. It is necessary to have centrifugal advance of the spark timing since the lean mixtures require an earlier spark timing than the rich mixtures.

a) True

b) False

Answer: b

Explanation: Actually, it is necessary to have vacuum advance of the spark timing since the lean mixtures require an earlier spark timing than the rich mixtures.

8. The ignition advance is obtained with the help of a spring loaded diaphragm connected to the _____________

a) throttle

b) nozzle

c) venturi

d) none of the mentioned

Answer: c

Explanation: The ignition advance is obtained with the help of a spring loaded diaphragm connected to the venturi and spring is not connected to nozzle or throttle.

9. The diaphragm is so coupled with the contact breaker that when induction pressure is reduced, the angle of advance _____________

a) decreases

b) increases

c) remains constant

d) none of the mentioned

Answer: b

Explanation: None.

10. The centrifugal spark advance is essential to compensate for the increase in speed of the engine.

a) True

b) False

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Combustion”.

1. ____________ is a chemical reaction in which certain elements of the fuel like hydrogen and carbon combine with oxygen liberating heat energy and causing an increase in temperature of the gases.

a) Compression

b) Expansion

c) Combustion

d) None of the mentioned

Answer: c

Explanation: Combustion is a chemical reaction in which certain elements of the fuel like hydrogen and carbon combine with oxygen liberating heat energy and causing an increase in temperature of the gases, while expansion and compression are not reactions, in fact they are processes in a fuel cycle.

2. The conditions necessary for combustion are the presence of combustible mixture and some means of initiating the process.

a) True

b) False

Answer: a

Explanation: None.

3. The process of combustion in engines generally takes place either in a homogeneous or a heterogeneous fuel vapour air mixture depending on the type of engine.

a) True

b) False

Answer: a

Explanation: None.

4. In spark ignition engines a nearly ____________ mixture of air and fuel is formed in the carburettor.

a) heterogeneous

b) homogeneous

c) solid

d) none of the mentioned

Answer: b

Explanation: In spark ignition engines a nearly homogeneous mixture of air and fuel is formed in the carburettor and solid and heterogeneous mixture is never used.

5. Homogeneous mixture is formed inside the engine cylinder and the combustion is initiated inside the cylinder at a particular instant towards the end of the compression stroke.

a) True

b) False

Answer: b

Explanation: In fact, homogeneous mixture is formed outside the engine cylinder and the combustion is initiated inside the cylinder at a particular instant towards the end of the compression stroke.

6. In a homogeneous gas mixture the fuel and oxygen molecules are more or less, uniformly distributed.

a) True

b) False

Answer: a

Explanation: Yes, homogeneous means equally distributed and in a homogeneous gas mixture the fuel and oxygen molecules are more or less, uniformly distributed.

7. The complete combustion of ____________ mixture, and droplet combustion result in the smoke and odour.

a) heterogeneous

b) homogeneous

c) solid

d) none of the mentioned

Answer: b

Explanation: Not, but the incomplete combustion of heterogeneous mixture, and droplet combustion result in the smoke and odour.

8. The ____________ rate is the result of a purely chemical combination process in which the flame eats it way into the unburned charge.

a) transposition

b) reaction

c) burning

d) none of the mentioned

Answer: b

Explanation: The reaction rate is the result of a purely chemical combination process in which the flame eats it way into the unburned charge while the transposition rate is due to the physical movement of the flame front relative to the cylinder wall and also the result of the pressure differential between the burning gases and the unburnt gases in the combustion chamber.

9. The ____________ rate is due to the physical movement of the flame front relative to the cylinder wall and also the result of the pressure differential between the burning gases and the unburnt gases in the combustion chamber.

a) transposition

b) reaction

c) burning

d) none of the mentioned

Answer: a

Explanation: The transposition rate is due to the physical movement of the flame front relative to the cylinder wall and also the result of the pressure differential between the burning gases and the unburnt gases in the combustion chamber while the reaction rate is the result of a purely chemical combination process in which the flame eats it way into the unburned charge.

10. A pre-combustion chamber gives a shorter delay compared to an open type of combustion chamber.

a) True

b) False

Answer: a

Explanation: None.

This set of IC Engine Problems focuses on “Abnormal Combustion”.

1. In ____________ combustion, the flame initiated by the spark travels across the combustion chamber in a fairly uniform manner.

a) abnormal

b) normal

c) knocking

d) none of the mentioned

Answer: b

Explanation: None.

2. In CI engines, abnormal combustion is not a great problem as in SI Engines.

a) True

b) False

Answer: a

Explanation: None.

3. ____________ knock occurs when the delay period is excessively long so that there is a large amount of fuel in the cylinder for the simultaneous explosion phase.

a) Petrol

b) Diesel

c) Kerosene

d) None of the mentioned

Answer: b

Explanation: None.

4. The rate of pressure rise per degree of crank angle is then so great that an audible knocking sound occurs.

a) True

b) False

Answer:a

Explanation: None.

5. Knock is a function of the fuel chosen and may be avoided by choosing a fuel with characteristics that do not give too long a delay period.

a) True

b) False

Answer: a

Explanation: None.

6. If detonation is allowed to persist under extreme conditions or over many engine cycles, engine parts can be damaged or destroyed.

a) True

b) False

Answer: a

Explanation: Yes, detonation leads to the damage of engine parts.

7. Detonation cannot be prevented by reducing peak cylinder pressure.

a) True

b) False

Answer: b

Explanation: In fact, detonation is prevented by reducing peak cylinder pressure.

8. Detonation can be prevented by increasing the manifold pressure by reducing the throttle opening.

a) True

b) False

Answer: b

Explanation: In actual practice, detonation can be prevented by decreasing the manifold pressure by reducing the throttle opening.

9. Knock is less common in ____________ climates.

a) hot

b) cold

c) normal

d) none of the mentioned

Answer: b

Explanation: Knock is less common in cold climates as compared to hot and moderate climates.

10. Diesel knock is the sound produced by the very rapid rate of pressure rise during the early part of the uncontrolled second phase of combustion.

a) True

b) False

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Knocking In S.I. Engine”.

1. In a spark ignition engine combustion which is initiated between the spark plug electrodes spreads across the combustible mixture.

a) True

b) False

Answer: a

Explanation: None.

2. A definite flame front is one that separates the fresh mixture from the products of combustion travels from the spark plug to the other end of the combustion chamber.

a) True

b) False

Answer: a

Explanation: None.

3. The process of autoignition has nothing to do towards engine knock.

a) True

b) False

Answer: b

Explanation: Actually, the process of autoignition leads towards engine knock.

4. In SI engine, ignition lag is reduced if the initial temperature and pressure are _____________

a) decreased

b) increased

c) constant

d) none of the mentioned

Answer: a

Explanation: In SI engine, due to the increment of the initial temperature and pressure are ignition lag is reduced.

5. Auto ignition refers to the initiation of combustion without the necessity of a flame.

a) True

b) False

Answer: a

Explanation: None.

6. What are the effects of knocking?

a) noise and roughness

b) mechanical damage

c) carbon deposits

d) all of the mentioned

Answer: a

Explanation: The effects of knocking are

i) noise and roughness

ii) mechanical damage

iii) carbon deposits

iv) increase in heat transfer

v) decrease in power output and efficiency

vi) preignition.

7. What are the effects of knocking?

a) increase in heat transfer

b) decrease in power output and efficiency

c) preignition

d) all of the mentioned

Answer: a

Explanation: The effects of knocking are

i) noise and roughness

ii) mechanical damage

iii) carbon deposits

iv) increase in heat transfer

v) decrease in power output and efficiency

vi) preignition.

8. Increase of pressure increases the self ignition temperature and the induction period.

a) True

b) False

Answer: b

Explanation: In fact, increase of pressure decreases the self ignition temperature and the induction period.

9. Low engine speeds will give low turbulence and low flame velocities and knock may occur at low speed.

a) True

b) False

Answer: a

Explanation: None.

10. Use of low octane fuel can eliminate detonation.

a) True

b) False

Answer: b

Explanation: No, but the use of high octane fuel can eliminate detonation.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Combustion In S.I. Engine”.

1. Swirl is the rotational flow of charge within the cylinder about the axis.

a) True

b) False

Answer: a

Explanation: None.

2. The _____________ is defined by the parallel portion of the piston and cylinder head which almost touch each other as the piston approaches T.D.C.

a) turbulence

b) swirl

c) quench area

d) none of the mentioned

Answer: c

Explanation: The quench area is defined by the parallel portion of the piston and cylinder head which almost touch each other as the piston approaches T.D.C. while turbulence consists of randomly dispersed vortices of different sizes which become superimposed into the air and petrol mixture flow stream.

3. ____________ consists of randomly dispersed vortices of different sizes which become superimposed into the air and petrol mixture flow stream.

a) Turbulence

b) Swirl

c) Quench area

d) None of the mentioned

Answer: a

Explanation: Only turbulence consists of randomly dispersed vortices of different sizes which become superimposed into the air and petrol mixture flow stream while quench area is defined by the parallel portion of the piston and cylinder head which almost touch each other as the piston approaches T.D.C.

4. The amount of vortex activity,and the disintegration of others, _____________ the turbulent flow with rising engine speed.

a) increases

b) decreases

c) remains same

d) none of the mentioned

Answer: a

Explanation: None.

5. The degree of turbulence increases _____________ with the piston speed.

a) indirectly

b) directly

c) linearly

d) none of the mentioned

Answer: b

Explanation: The degree of turbulence is directly proportional to piston speed, hence it increases directly with the piston speed.

6. Turbulence decreases the heat flow to the cylinder wall and in the limit excessive turbulence may extinguish the flame.

a) True

b) False

Answer: b

Explanation: In fact, turbulence increase the heat flow to the cylinder wall and in the limit excessive turbulence may extinguish the flame.

7. The flame propagation velocities range from _____________

a) 10 to 15 m/s

b) 15 to 70 m/s

c) 20 to 80 m/s

d) 30 to 90 m/s

Answer: a

Explanation: None.

8. When ignition occurs the nucleus of the flame spreads with the whirling or rotating vortices in the form of ragged burning crust from the initial spark plug ignition site.

a) True

b) False

Answer: a

Explanation: None.

9. Swirl ratio is defined as the ratio of air rotational speed to crankshaft rotational speed.

a) True

b) False

Answer: a

Explanation: None.

10. Abnormal combustion knock produced by surface ignition in SI engines is not harmful as normal combustion knock.

a) True

b) False

Answer: b

Explanation: In fact, abnormal combustion knock produced by surface ignition in SI engines is more harmful than normal combustion knock.

This set of Basic IC Engine Questions and Answers focuses on “Combustion In C.I. Engine”.

1. In CI engine, combustion occurs by the high temperature produced by the compression of the air.

a) True

b) False

Answer: a

Explanation: None.

2. In the CI engine, the intake is air alone and the fuel is injected at high pressure in the form of fine droplets at the start of compression.

a) True

b) False

Answer: b

Explanation: No, but actually, in the CI engine, the intake is air alone and the fuel is injected at high pressure in the form of fine droplets near the end of compression.

3. What are the phases of CI engine combustion?

a) ignition delay period

b) period of rapid combustion

c) period of controlled combustion

d) all of the mentioned

Answer: d

Explanation: The three phases of CI engine combustion are

i) ignition delay period

ii) period of rapid combustion

iii) period of controlled combustion.

4. The rate of pressure rise depends on the amount of fuel present at the end of delay period, degree of turbulence, fineness of atomization and spray pattern.

a) True

b) False

Answer: a

Explanation: None.

5. Which of the following factors affecting combustion in the CI engine?

a) ignition quantity of fuel

b) injection pressure of droplet size

c) injection advance angle

d) all of the mentioned

Answer: a

Explanation: The factors affecting combustion in CI engine are

i) ignition quantity of fuel

ii) injection pressure of droplet size

iii) injection advance angle

iv) compression ratio

v) intake temperature

vi) jacket water temperature

vii) intake pressure

vii) engine speed

ix) load and air to fuel ratio

x) engine size

xi) type of combustion chamber.

6. Which of the following factors affecting combustion in the CI engine?

a) compression ratio

b) intake temperature

c) jacket water temperature

d) all of the mentioned

Answer: a

Explanation: The factors affecting combustion in CI engine are

i) ignition quantity of fuel

ii) injection pressure of droplet size

iii) injection advance angle

iv) compression ratio

v) intake temperature

vi) jacket water temperature

vii) intake pressure

vii) engine speed

ix) load and air to fuel ratio

x) engine size

xi) type of combustion chamber.

7. Which of the following factors affecting combustion in the CI engine?

a) intake pressure

b) engine speed

c) load and air to fuel ratio

d) all of the mentioned

Answer: a

Explanation: The factors affecting combustion in CI engine are

i) ignition quantity of fuel

ii) injection pressure of droplet size

iii) injection advance angle

iv) compression ratio

v) intake temperature

vi) jacket water temperature

vii) intake pressure

vii) engine speed

ix) load and air to fuel ratio

x) engine size

xi) type of combustion chamber.

8. Towards the end of the compression stroke when injection of the fuel into the combustion chamber commences, the quantity of fuel discharged is spread out over a predetermined period.

a) True

b) False

Answer: a

Explanation: None.

9. The rate of burning does not depend on the relative movement of the burning droplets to the surrounding air charge.

a) True

b) False

Answer: b

Explanation: In fact, the rate of burning depends on the relative movement of the burning droplets to the surrounding air charge.

10. In CI engines fuel is injected into the combustion chamber at about 15ºC ___________ TDC during compression stroke.

a) after

b) before

c) at

d) none of the mentioned

Answer: b

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Delay Period”.

1. ___________ is the time immediately following injection of the fuel during which the ignition process is being initiated and the pressure does not rise beyond the value it would have due to compression of air.

a) Knocking

b) Delay period

c) Startability

d) None of the mentioned

Answer: b

Explanation: Delay period is defined as the time immediately following injection of the fuel during which the ignition process is being initiated and the pressure does not rise beyond the value it would have due to compression of air.

2. The ___________ extends for about 13º, movement of the crank.

a) knocking

b) delay period

c) start ability

d) none of the mentioned

Answer: b

Explanation: None.

3. The time for which delay period occurs decreases with ___________ in engine speed.

a) increases

b) decreases

c) unpredictable

d) none of the mentioned

Answer: a

Explanation: None.

4. Delay period serves a useful purpose in that it allows the fuel jet to penetrate well into the combustion space.

a) True

b) False

Answer: a

Explanation: None.

5. If the delay is too short the amount of fuel available for the simultaneous explosion is too great and the resulting pressure rise is too rapid.

a) True

b) False

Answer: b

Explanation: No, in fact, if the delay is too long the amount of fuel available for a simultaneous explosion is too great and the resulting pressure rise is too rapid.

6. The delay period depends upon temperature and pressure in the cylinder at the time of injection.

a) True

b) False

Answer: a

Explanation: None.

7. The delay period ___________ with load.

a) increases

b) decreases

c) unpredictable

d) none of the mentioned

Answer: a

Explanation: Delay period is directly proportional to load, so the delay period increases with load.

8. The delay period depends upon the nature of the fuel mixture strength.

a) True

b) False

Answer: a

Explanation: None.

9. Higher cetane number means a ___________ delay period and smoother engine operation.

a) higher

b) lower

c) normal

d) none of the mentioned

Answer: a

Explanation: None.

10. Increase in compression ratio ___________ delay period.

a) increases

b) reduces

c) unpredictable

d) none of the mentioned

Answer: b

Explanation: Compression ratio is indirectly proportional to delay period, so an increase in compression ratio reduces delay period.

11. At constant speed, delay period is proportional to the delay angle.

a) True

b) False

Answer: a

Explanation: None.

12. A pre-combustion chamber gives a shorter delay compared to an open type of combustion chamber.

a) True

b) False

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Engine Friction”.

1. The bearing friction includes the friction due to the main bearing connecting rod bearing and other bearings.

a) True

b) False

Answer: a

Explanation: None.

2. Bearing friction is viscous in nature and does not depends upon the oil viscosity, the speed, size and geometry of the journal.

a) True

b) False

Answer: b

Explanation: No, actually, bearing friction is viscous in nature and depends upon the oil viscosity, the speed, size and geometry of the journal.

3. The valve gear friction losses vary with the engine design variables and no general equation is available predicting them.

a) True

b) False

Answer: a

Explanation: None.

4. The blow by losses is the phenomenon of leakage of combustion products past the piston and piston rings from the cylinder to the crankcase.

a) True

b) False

Answer: a

Explanation: None.

5. Blow by losses depend on the outlet pressure and compression ratio.

a) True

b) False

Answer: b

Explanation: In fact, blow by losses depends on the inlet pressure and compression ratio.

6. Blow by losses vary as the square root of inlet pressure, and increases as the compression ratio are ____________

a) increased

b) reduced

c) unpredictable

d) none of the mentioned

Answer: a

Explanation: None.

7. Blow by losses are reduced as the engine speed is ____________

a) increased

b) reduced

c) unpredictable

d) none of the mentioned

Answer: a

Explanation: Blow by losses are indirectly proportional to engine speed and it is reduced as the engine speed is increased.

8. A rise in cooling water temperature ____________ engine friction through its effect on oil viscosity.

a) increases

b) reduces

c) unpredictable

d) none of the mentioned

Answer: b

Explanation: None.

9. Higher the oil viscosity ____________ is the friction loss.

a) lower

b) greater

c) unpredictable

d) none of the mentioned

Answer: b

Explanation: Viscosity is proportional to friction loss, so higher the oil viscosity greater is the friction loss.

10. As the load increases the maximum pressure in the cylinder has a tendency to increase slightly.

a) True

b) False

Answer: a

Explanation: None.

This set of IC Engine Assessment Questions and Answers focuses on “Mechanical Friction”.

1. The hydrodynamic friction is associated with the phenomena when a complete film of lubricant exists between the two bearing surfaces.

a) True

b) False

Answer: a

Explanation: None.

2. In hydrodynamic friction, the friction force does not depends on the lubricant viscosity.

a) True

b) False

Answer: b

Explanation: In fact, in hydrodynamic friction, the friction force entirely depends on the lubricant viscosity.

3. During normal engine operation there is almost no metallic contact except between the compression piston ring and cylinder walls.

a) True

b) False

Answer: a

Explanation: None.

4. During starting of the engine, the journal bearings operate in ____________ friction.

a) rolling

b) hydrodynamic friction

c) partial-film

d) none of the mentioned

Answer: c

Explanation: None.

5. The ____________ friction is due to rolling motion between the two surfaces.

a) rolling

b) hydrodynamic friction

c) partial-film

d) none of the mentioned

Answer: a

Explanation: None.

6. Ball and roller bearings and tappet rollers are subjected to rolling friction.

a) True

b) False

Answer: a

Explanation: None.

7. Rolling friction coefficient is ____________ than journal bearing friction coefficient during starting and initial running of engine.

a) higher

b) lower

c) faster

d) none of the mentioned

Answer: b

Explanation: None.

8. A circular cylindrical shaft called journal rotates against a cylindrical surface called the bearing.

a) True

b) False

Answer: a

Explanation: None.

9. Total friction is negligible compared to rolling friction.

a) True

b) False

Answer: b

Explanation: No, but rolling friction is negligible compared to total friction.

10. The mechanical friction ___________ with increase in speed.

a) increases

b) reduces

c) unpredictable

d) none of the mentioned

Answer: a

Explanation: Mechanical friction is directly proportional to engine speed, so mechanical friction increases with an increase in speed.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Total Engine Friction”.

1. The difference between I.P. and B.P. is known as total engine friction loss.

a) True

b) False

Answer: a

Explanation: None.

2. In four stroke cycle engines, an ample amount of ____________ is used during intake and exhaust processes.

a) heat

b) pressure

c) power

d) none of the mentioned

Answer: c

Explanation: None.

3. The pumping loss is negligible in two-stroke cycle engines.

a) True

b) False

Answer: a

Explanation: The pumping loss is negligible in two-stroke cycle engines since the incoming fresh mixture is used for scavenging the exhaust gases and charging the cylinder.

4. The standard practice for sizing the exhaust valve is to make them a certain percentage ____________ than the inlet valves.

a) larger

b) smaller

c) unpredictable

d) none of the mentioned

Answer: b

Explanation: None.

5. If due attention is not given to the valve size, valve timing and valve flow coefficients there may be a substantial loss with the increase in engine speed.

a) True

b) False

Answer: a

Explanation: None.

6. The exhaust throttling loss occurs due to the restrictions imposed by air cleaner, carburetor venturi, throttle valve, intake manifold and intake valve.

a) True

b) False

Answer: b

Explanation: The inlet throttling loss occurs due to the restrictions imposed by air cleaner, carburetor venturi, throttle valve, intake manifold and intake valve.

7. Combustion chamber pump loss is caused due to the pumping work required to pump gases into and out of the pre-combustion chamber.

a) True

b) False

Answer: a

Explanation: None.

8. ____________ losses are caused due to the leakage of combustion products past the piston from the cylinder into the crankcase.

a) Pumping

b) Blowby

c) Pressure

d) None of the mentioned

Answer: b

Explanation: None.

9. Blowby losses ____________ directly with compression ratio.

a) increases

b) decreases

c) remains same

d) none of the mentioned

Answer: b

Explanation: None.

10. When a smaller number of large cylinders are used, the friction and economy improve.

a) True

b) False

Answer: a

Explanation: None.

11. The frictional mean effective pressure ____________ as the compression ratio is increased.

a) increases

b) decreases

c) remains same

d) none of the mentioned

Answer: a

Explanation: None.

This set of IC Engine Interview Questions and Answers for freshers focuses on “Ignition Timing and Engine Parameters”.

1. If the engine is operating with richer mixtures the optimum spark timing must be _____________

a) constant

b) increased

c) retarded

d) none of the mentioned

Answer: c

Explanation: If the engine is operating with richer mixtures the optimum spark timing must be retarded as if the mixture is rich it has its low self ignition temperature.

2. Part load operation of a spark ignition engine is not affected by throttling the incoming charge.

a) True

b) False

Answer: b

Explanation: In fact, part load operation of a spark ignition engine is affected by throttling the incoming charge.

3. Due to throttling a smaller amount of charge enters the cylinder and the dilution due to residual gases is also greater.

a) True

b) False

Answer: a

Explanation: None.

4. Ignition delay does not depend upon the type of the fuel used in the engine.

a) True

b) False

Answer: b

Explanation: Actually, ignition delay will depend upon the type of the fuel used in the engine.

5. For maximum power and economy a slow burning fuel needs a higher spark advance than fast burning fuel.

a) True

b) False

Answer: a

Explanation: None.

6. The ignition timing is fixed to obtain minimum power from the engine.

a) True

b) False

Answer: b

Explanation: In fact, the ignition timing is fixed to obtain maximum power from the engine.

7. The ignition timing is affected by _____________

a) compression ratio

b) engine speed

c) mixture strength

d) all of the mentioned

Answer: d

Explanation: The ignition timing is affected by

i) compression ratio

ii) engine speed

iii) mixture strength

iv) combustion chamber design

v) throttle opening

vi) engine temperature

vii) type of fuel.

8. The ignition timing is affected by _____________

a) combustion chamber design

b) throttle opening

c) engine temperature

d) all of the mentioned

Answer: d

Explanation: The ignition timing is affected by

i) compression ratio

ii) engine speed

iii) mixture strength

iv) combustion chamber design

v) throttle opening

vi) engine temperature

vii) type of fuel.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Properties Of Lubrication – 1”.

1. Which of the following are the properties of lubricants?

a) viscosity

b) flash point

c) fire point

d) all of the mentioned

Answer: b

Explanation: The properties of lubricants are

i) viscosity

ii) flash point

iii) fire point

iv) cloud point

v) pour point

vi) corrosion

vii) physical stability

viii) neutralisation number

ix) film strength

x) oiliness

xi) emulsification

xii) chemical stability

xiii) adhesiveness

xiv) specific gravity.

2. ____________ is the ability of the oil to resist internal deformation due to mechanical stresses.

a) Viscosity

b) Flash point

c) Fire point

d) None of the mentioned

Answer: a

Explanation: Viscosity is the ability of the oil to resist internal deformation due to mechanical stresses and hence it is a measure of the ability of the oil film to carry a load.

3. A more viscous oil can carry a greater load, but it will offer great friction to sliding movement of the one bearing surface over the other.

a) True

b) False

Answer: a

Explanation: None.

4. Viscosity varies with the temperature and hence if a surface to be lubricated is normally at high temperature it should be supplied with oil of higher viscosity.

a) True

b) False

Answer: a

Explanation: None.

5. The viscosity is measured by ____________

a) barometer

b) thermometer

c) viscosimeter

d) none of the mentioned

Answer: c

Explanation: The viscosity is measured by viscosimeter.

6. A high viscosity index indicates relatively ____________ changes in viscosity of the oil with the temperature.

a) larger

b) smaller

c) constant

d) none of the mentioned

Answer: b

Explanation: None.

7. Pour point is the lowest temperature at which the lubricating oil will flash when a small flame is passed across its surface.

a) True

b) False

Answer: b

Explanation: Actually, flash point is the lowest temperature at which the lubricating oil will flash when a small flame is passed across its surface.

8. The flash point of the oil should be sufficiently high so as to avoid flashing of oil vapours at the temperatures occurring in common use.

a) True

b) False

Answer: a

Explanation: None.

9. ____________ is the lowest temperature at which the oil burns continuously.

a) Viscosity

b) Flash point

c) Fire point

d) None of the mentioned

Answer: c

Explanation: Fire point is the lowest temperature at which the oil burns continuously while viscosity is the ability of the oil to resist internal deformation due to mechanical stresses.

10. ____________ is the lowest temperature at which the lubricating oil will pour.

a) Viscosity

b) Pour point

c) Fire point

d) None of the mentioned

Answer: b

Explanation: Pour point is the lowest temperature at which the lubricating oil will pour while fire point is the lowest temperature at which the oil burns continuously and viscosity is the ability of the oil to resist internal deformation due to mechanical stresses.

This set of IC Engine Questions and Answers for Experienced people focuses on “Properties Of Lubrication – 2”.

1. ____________ is the property which enables oil to spread over and adhere to the surface of the bearing.

a) Oiliness

b) Pour point

c) Fire point

d) None of the mentioned

Answer: a

Explanation: Oiliness is the property which enables oil to spread over and adhere to the surface of the bearing and pour point is the lowest temperature at which the lubricating oil will pour while fire point is the lowest temperature at which the oil burns continuously.

2. A lubricant should not corrode the working parts and it must retain its properties even in the presence of foreign matter and additives.

a) True

b) False

Answer: a

Explanation: None.

3. A lubricating oil, when mixed with water is emulsified and loses its lubricating property.

a) True

b) False

Answer: a

Explanation: None.

4. The emulsification number is an index of the tendency of an oil to emulsify with water.

a) True

b) False

Answer: a

Explanation: None.

5. A lubricating oil need not be stable physically at the lowest and highest temperatures between which the oil is to be used.

a) True

b) False

Answer: b

Explanation: Actually, a lubricating oil must be stable physically at the lowest and highest temperatures between which the oil is to be used.

6. At the lowest temperature there should separation of solids, and at the highest temperature it should not vapourise beyond a certain limit.

a) True

b) False

Answer: b

Explanation: No, at the lowest temperature there should not be any separation of solids, and at the highest temperature it should not vapourise beyond a certain limit.

7. ____________ is the property of lubricating oil due to which the oil particles stick with the metal surfaces.

a) Oiliness

b) Pour point

c) Adhesiveness

d) None of the mentioned

Answer: c

Explanation: Adhesiveness is the property of lubricating oil due to which the oil particles stick with the metal surfaces while oiliness is the property which enables oil to spread over and adhere to the surface of the bearing.

8. ____________ is the property of a lubricating oil due to which the oil retains a thin film between the two surfaces.

a) Oiliness

b) Film Strength

c) Adhesiveness

d) None of the mentioned

Answer: b

Explanation: Film Strength is the property of a lubricating oil due to which the oil retains a thin film between the two surfaces and adhesiveness is the property of lubricating oil due to which the oil particles stick with the metal surfaces while oiliness is the property which enables oil to spread over and adhere to the surface of the bearing.

9. ____________ is the measure of density of oil.

a) Specific gravity

b) Film Strength

c) Adhesiveness

d) None of the mentioned

Answer: b

Explanation: Specific gravity is the measure of density of oil while film Strength is the property of a lubricating oil due to which the oil retains a thin film between the two surfaces and adhesiveness is the property of lubricating oil due to which the oil particles stick with the metal surfaces.

10. The sludge formation takes place as a result of operation at low engine temperatures during starting, warming up, and idling periods.

a) True

b) False

Answer: a

Explanation: None.

11. A high viscosity index is always desired for lubricating oils as it can be used in severe winter and summer conditions.

a) True

b) False

Answer: b

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Types Of Lubricants”.

1. The ____________ are obtained from the residual mass left during crude petroleum distillation.

a) fatty oils

b) synthetic lubricants

c) mineral lubricating oils

d) none of the mentioned

Answer: c

Explanation: None.

2. Parafins crudes generally give a lower yield of lubricating oils than naphthenic crudes.

a) True

b) False

Answer: b

Explanation: Actually, paraffin crudes generally give a higher yield of lubricating oils than naphthenic crudes.

3. In mineral lubricating oils, bubble towers are used for fractionalisation of oil into two or three fractions of different viscosities.

a) True

b) False

Answer: a

Explanation: None.

4. Fatty oils from animal and vegetable origin are sometimes used alone but are frequently mixed with mineral oils.

a) True

b) False

Answer: b

Explanation: None.

5. Olive oil is employed for lubricating textile machinery.

a) True

b) False

Answer: a

Explanation: Olive oil is employed for lubricating textile machinery, as it can be easily washed out from cloth without leaving any stain.

6. Lard oil is used for making lubricants for railway engines.

a) True

b) False

Answer: b

Explanation: Rapeseed oil is used for making lubricants for railway engines.

7. Rapeseed oil is used for producing lubricants for internal combustion engines.

a) True

b) False

Answer: b

Explanation: Lard oil is used for producing lubricants for internal combustion engines.

8. Caster oil is usually compounded with heavy mineral oils for making extreme pressure lubricants.

a) True

b) False

Answer: a

Explanation: None.

9. Which of the following are the types of synthetic lubricants?

a) dibasic acid esters

b) organo-phosphate esters

c) silicate esters

d) all of the mentioned

Answer: d

Explanation: The types of synthetic lubricants are

i) dibasic acid esters

ii) organo-phosphate esters

iii) silicate esters

iv) silicon polymers

v) polyglycolethers and related compounds

vi) fluorinated and chlorinated hydrocarbon compounds.

10. Which of the following are the types of synthetic lubricants?

a) silicon polymers

b) polyglycolethers and related compounds

c) fluorinated and chlorinated hydrocarbon compounds

d) all of the mentioned

Answer: d

Explanation: The types of synthetic lubricants are

i) dibasic acid esters

ii) organo-phosphate esters

iii) silicate esters

iv) silicon polymers

v) polyglycolethers and related compounds

vi) fluorinated and chlorinated hydrocarbon compounds.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Classification Of Lubricating System – 1”.

1. Lubricating grease is a solid to semi-solid dispersion of a thickening agent in a liquid lubricant.

a) True

b) False

Answer: a

Explanation: None.

2. Greases perform better than oils under conditions requiring ___________

a) high bearing loads and shock loads

b) slow journal speed

c) temperature extremes

d) all of the mentioned

Answer: d

Explanation: Greases perform better than oils under conditions requiring

i) high bearing loads and shock loads

ii) slow journal speed

iii) temperature extremes

iv) cleanliness or avoidance of splash

v) minimum attention

vi) a seal against external contaminants

vii) large bearing clearances.

3. Greases perform better than oils under which of the following conditions?

a) cleanliness or avoidance of splash

b) minimum attention

c) a seal against external contaminants

d) all of the mentioned

Answer: d

Explanation: Greases perform better than oils under conditions requiring

i) high bearing loads and shock loads

ii) slow journal speed

iii) temperature extremes

iv) cleanliness or avoidance of splash

v) minimum attention

vi) a seal against external contaminants

vii) large bearing clearances.

4. What are the various types of greases used for lubrication?

a) calcium soap greases

b) sodium soap greases

c) aluminium soap greases

d) all of the mentioned

Answer: d

Explanation: The various types of greases used for lubrication are

i) calcium soap greases

ii) sodium soap greases

iii) aluminium soap greases

iv) mixed soap greases

v) barium soap greases

vi) lithium soap greases

vii) pure petroleum greases.

5. Wet sump lubrication system employ a large capacity oil sump at the base of crank chamber, from which the oil is drawn by a low pressure oil pump and delivered to various parts.

a) True

b) False

Answer: a

Explanation: None.

6. Splash system is suitable for high and medium speed engines having moderate bearing load pressures.

a) True

b) False

Answer: b

Explanation: In fact, splash system is suitable for low and medium speed engines having moderate bearing load pressures.

7. Semi pressure system is a combination of splash and pressure systems.

a) True

b) False

Answer: a

Explanation: None.

8. Semi pressure system does not enables higher bearing loads and engine speeds to be employed as compared to splash system.

a) True

b) False

Answer: b

Explanation: Semi pressure system enables higher bearing loads and engine speeds to be employed as compared to splash system.

9. In full pressure system, oil from the oil sump is pumped under pressure to the various parts requiring lubrication.

a) True

b) False

Answer: a

Explanation: None.

10. Full pressure sump lubrication system is generally adopted for high capacity engines.

a) True

b) False

Answer: b

Explanation: Dry sump lubrication system is generally adopted for high capacity engines.

This set of IC Engine Interview Questions and Answers for Experienced people focuses on “Classification Of Lubricating System – 2”.

1. Mist lubrication system is used for ____________ stroke cycle engines.

a) four

b) two

c) unpredictable

d) none of the mentioned

Answer: b

Explanation: None.

2. In the drip system oil is fed to machine parts drop by drop, from an oil cup.

a) True

b) False

Answer: a

Explanation: None.

3. The ball and roller bearings are lubricated to reduce friction and wear between the sliding parts of the bearing.

a) True

b) False

Answer: a

Explanation: None.

4. The ball and roller bearings are lubricated to prevent rusting or corrosion of bearing surfaces.

a) True

b) False

Answer: a

Explanation: None.

5. All the lubricating oil from the oil sump, must pass through an oil filter before it is supplied to the engine bearings.

a) True

b) False

Answer: b

Explanation: All the lubricating oil from the oil sump, must pass through an oil filter before it is supplied to the engine bearings.

6. Bearings maintain very close tolerances and are likely to be damaged by an foreign abrasive material entering the lubrication line.

a) True

b) False

Answer: a

Explanation: None.

7. In by pass type filter arrangement, only a small portion of the lubricating oil is passed through the filter and the remaining lubricating oil is directly supplied to the bearings by the oil pump at pre-set pressure.

a) True

b) False

Answer: a

Explanation: None.

8. In full flow type filter arrangement, whole of the oil is filtered before it is supplied to various bearings.

a) True

b) False

Answer: b

Explanation: In full flow type filter arrangement, whole of the oil is filtered before it is supplied to various bearings.

9. All the lubricating oil, in normal course, should be filtered approximately every minute.

a) True

b) False

Answer: b

Explanation: But in fact, all the lubricating oil, in normal course, should be filtered approximately every half minute.

10. In a closed system, the fresh air supply is taken to the crankcase from the carburetor.

a) True

b) False

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Heat Rejection”.

1. The transfer of heat takes place due to difference in temperature and from higher temperature to lower temperature.

a) True

b) False

Answer: a

Explanation: None.

2. The hot gases give part of their heat to ____________

a) cylinder liner

b) piston and piston rings

c) cylinder head

d) all of the mentioned

Answer: d

Explanation: The hot gases give part of their heat to

i) cylinder liner

ii) piston and piston rings

iii) cylinder head

iv) exhaust valves and exhaust ports.

3. Most of the heat is carried away by the cooling system while some are lost by direct radiation from the engine surfaces.

a) True

b) False

Answer: a

Explanation: None.

4. At the end of the induction stroke the temperature is that of clearance gases.

a) True

b) False

Answer: b

Explanation: No, but in fact, at the beginning of induction stroke the temperature is that of clearance gases.

5. As the cool mixture is inducted into the engine cylinder the temperature rises rapidly.

a) True

b) False

Answer: b

Explanation: Actually, as the cool mixture is inducted into the engine cylinder the temperature falls rapidly.

6. During compression process the temperature ____________ and attains its maximum value at the end of combustion process.

a) decreases

b) increases

c) remains same

d) none of the mentioned

Answer: b

Explanation: During compression process the temperature increases and attains its maximum value at the end of combustion process while during the expansion process the temperature decreases and then drops very rapidly during the release process.

7. During the expansion process the temperature ____________ and then drops very rapidly during the release process.

a) decreases

b) increases

c) remains same

d) none of the mentioned

Answer: a

Explanation: During the expansion process the temperature decreases and then drops very rapidly during the release process while during the compression process the temperature increases and attains its maximum value at the end of the combustion process.

8. Inadequate lubrication of the engine, due to oil not being warm enough to flow freely, results in greater frictional losses.

a) True

b) False

Answer: a

Explanation: None.

9. A hot-spot outside the combustion chamber may be sufficient to cause pre-ignition.

a) True

b) False

Answer: b

Explanation: In fact, a hot-spot inside the combustion chamber may be sufficient to cause pre-ignition.

10. If the engine is overcooled some of the heat which could be used to expand the gases will be lost.

a) True

b) False

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Engine Heat Transfer”.

1. ____________ is the transfer of heat from one part of a substance to another part of the same substance.

a) Convection

b) Conduction

c) Radiation

d) None of the mentioned

Answer: b

Explanation: Conduction is defined as the transfer of heat from one part of a substance to another part of the same substance while convection is defined as the transfer of heat within a fluid by mixing of one portion of the fluid with another.

2. ____________ is the transfer of heat within a fluid by mixing of one portion of fluid with another.

a) Convection

b) Conduction

c) Radiation

d) None of the mentioned

Answer: a

Explanation: Convection is defined as the transfer of heat within a fluid by mixing of one portion of fluid with another while conduction is defined as the transfer of heat from one part of a substance to another part of the same substance.

3. ____________ convection occurs when the fluid circulates by virtue of the natural differences in densities of hot and cold fluids.

a) Forced

b) Natural

c) Unpredictable

d) None of the mentioned

Answer: b

Explanation: None.

4. In natural convection, the denser portions of the fluid move downward because of the greater force of gravity, as compared with the force on the less dense.

a) True

b) False

Answer: a

Explanation: None.

5. When the work is done to blow or pump the fluid, it is said to be ____________ convection.

a) natural

b) forced

c) unpredictable

d) none of the mentioned

Answer: b

Explanation: When the work is done to blow or pump the fluid, it is said to be forced convection while natural convection occurs when the fluid circulates by virtue of the natural differences in densities of hot and cold fluids.

6. ____________ is the transfer of heat through space or matter by means other than conduction or convection.

a) Forced

b) Natural

c) Radiation

d) None of the mentioned

Answer: c

Explanation: Radiation is the transfer of heat through space or matter by means other than conduction or convection and when the work is done to blow or pump the fluid, it is said to be forced convection while natural convection occurs when the fluid circulates by virtue of the natural differences in densities of hot and cold fluids.

7. In the case of air cooling, the boundary layer as on the gas side offers great resistance, but the effect of this is compensated largely by providing more surface areas by way of cooling pins.

a) True

b) False

Answer: a

Explanation: Yes, in case of air cooling, the boundary layer as on the gas side offers great resistance, but the effect of this is compensated largely by providing more surface areas by way of cooling pins.

8. In the case of water cooling, there no boundary layer of the liquid coolant on the outside of the cylinder wall.

a) True

b) False

Answer: b

Explanation: Actually, in the case of water cooling, there is also a boundary layer of the liquid coolant on the outside of the cylinder wall.

9. When the spark advance is same as the optimum value the heat rejected to cooling system is increased.

a) True

b) False

Answer: b

Explanation: In fact, when the spark advance is different from the optimum value the heat rejected to the cooling system is increased.

10. Gas temperature remains at a higher average with increased speed.

a) True

b) False

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Engine Cooling System”.

1. The gasoline engine requires much ____________ air than a diesel engine.

a) less

b) more

c) equal

d) none of the mentioned

Answer: b

Explanation: As a gasoline engine works on a mixture of air and gasoline, therefore the gasoline engine requires much more air than a diesel engine.

2. The turbocharged diesel engine requires ____________ cooling air than naturally aspired diesel engines.

a) less

b) more

c) equal

d) none of the mentioned

Answer: a

Explanation: As the turbocharged engine produces less heat so, the turbocharged diesel engine requires less cooling air than naturally aspired diesel engines.

3. The heat flow to water jackets, on an average, is about ____________ for large engines.

a) 500 kJ/kW-h

b) 4200 kJ/kW-h

c) 5700 kJ/kW-h

d) none of the mentioned

Answer: b

Explanation: The heat flow to water jackets, on an average is about 4200 kJ/kW-h for large engines and it is about 500-5700 kJ/kW-h for small engines.

4. The heat flow to water jackets, on average, is about ____________ for small engines.

a) 500-6200 kJ/kW-h

b) 400-4200 kJ/kW-h

c) 500-5700 kJ/kW-h

d) none of the mentioned

Answer: c

Explanation: The heat flow to water jackets, on average, is about 500-5700 kJ/kW-h for small engines and is about 4200 kJ/kW-h for large engines.

5. What is the outlet cooling water temperature for large engines?

a) about 50ºC

b) 60 to 65ºC

c) 80ºC

d) none of the mentioned

Answer: a

Explanation: The outlet cooling water temperature for large engines is about 50ºC and the outlet cooling water temperature for medium engines is 60 to 65ºC.

6. What is the outlet cooling water temperature for medium engines?

a) about 50ºC

b) 60 to 65ºC

c) 80ºC

d) none of the mentioned

Answer: b

Explanation: The outlet cooling water temperature for medium engines is 60 to 65ºC and the outlet cooling water temperature for small engines is 80ºC.

7. What is the outlet cooling water temperature for small engines?

a) about 50ºC

b) 60 to 65ºC

c) 80ºC

d) none of the mentioned

Answer: c

Explanation: The outlet cooling water temperature for small engines is 80ºC while the outlet cooling water temperature for medium engines is 60 to 65ºC and the outlet cooling water temperature for small engines is 80ºC.

8. In thermo-syphon system, the radiator should be kept well above the engine, to provide a height for natural circulation.

a) True

b) False

Answer: a

Explanation: None.

This set of IC Engine Questions and Answers for Aptitude test focuses on “Liquid Cooling Systems”.

1. In liquid cooling, the cylinder walls and heads are provided with jackets through which the cooling liquid can circulate.

a) True

b) False

Answer: a

Explanation: None.

2. In liquid cooling, the liquid becomes heated in its passage through the jackets and is itself cooled by means of an air-cooled radiator system.

a) True

b) False

Answer: a

Explanation: None.

3. The coolant to be employed in liquid cooling system should have ______________

a) low freezing temperature

b) a high boiling point

c) a large latent heat of vaporisation

d) all of the mentioned

Answer: d

Explanation: The coolant to be employed in liquid cooling system should have

i) low freezing temperature

ii) a high boiling point

iii) a large latent heat of vaporisation

iv) non-corrosive

v) easily and cheaply available.

4. Anti-freeze mixtures are added to fuel in extreme winter seasons to lower its freezing temperatures below the danger point.

a) True

b) False

Answer: b

Explanation: No, but actually, anti-freeze mixtures are added to water in extreme winter seasons to lower its freezing temperatures below the danger point.

5. Which of the following are commonly used in anti-freeze materials?

a) denatured alcohol

b) wood alcohol

c) glycerin

d) all of the mentioned

Answer: d

Explanation: Commonly used anti-freeze materials are

i) denatured alcohol

ii) wood alcohol

iii) glycerin

iv) kerosene

v) sugar solution

vi) calcium or magnesium chloride

vii) ethylene glycol and proplene glycol.

6. Which of the following are commonly used in anti-freeze materials?

a) kerosene

b) sugar solution

c) calcium or magnesium chloride

d) all of the mentioned

Answer: d

Explanation: Commonly used anti-freeze materials are

i) denatured alcohol

ii) wood alcohol

iii) glycerin

iv) kerosene

v) sugar solution

vi) calcium or magnesium chloride

vii) ethylene glycol and proplene glycol.

7. What are the various methods used for circulating water around the cylinder and cylinder heads?

a) thermo-syphon cooling

b) forced or pump cooling

c) cooling with thermostatic regulator

d) all of the mentioned

Answer: d

Explanation: The various methods used for circulating water around the cylinder and cylinder heads are

i) thermo-syphon cooling

ii) forced or pump cooling

iii) cooling with thermostatic regulator

iv) pressurized water cooling

v) evaporative cooling.

8. The thermo-syphon cooling system can be used in high output engines due to its inability to meet the requirement of large flow rates of water.

a) True

b) False

Answer: b

Explanation: In fact, the thermo-syphon cooling system are avoided to be used in high output engines due to its inability to meet the requirement of large flow rates of water.

9. In thermo-syphon cooling system, the cooling only depends on temperature and is independent of the engine speed.

a) True

b) False

Answer: a

Explanation: None.

10. The circulation of water starts only after the engine has become hot enough to cause thermo-syphon.

a) True

b) False

Answer: a

Explanation: None.

11. The main disadvantage of forced cooling is that cooling is ensured under all conditions of operation.

a) True

b) False

Answer: b

Explanation: No, but actually, it is the main advantage of forced cooling is that cooling is ensured under all conditions of operation.

12. Which of the following are the components of a water cooling system?

a) water jacket

b) water pump

c) fan

d) all of the mentioned

Answer: a

Explanation: Components of the water cooling system are

i) water jacket

ii) water pump

iii) fan

iv) thermostat

v) connecting hoses

vi) radiators

vii) radiator cap.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Air Cooled Systems”.

1. Air cooling system is used in small engines whose application gives extreme importance to weight such as aircraft engines.

a) True

b) False

Answer: a

Explanation: Yes, air cooling system is used in small engines whose application gives extreme importance to weight such as aircraft engines while air cooling system is used in industrial and agricultural engines where there can be a strong objection to use of water as a coolant.

2. Air cooling system is used in industrial and agricultural engines where there can be a strong objection to use of water as a coolant.

a) True

b) False

Answer: a

Explanation: Air cooling system is used in industrial and agricultural engines where there can be a strong objection to use of water as coolant while air cooling system is used in small engines whose application gives extreme importance to weight such as aircraft engines.

3. The volumetric efficiency of an air-cooled engine is higher due to high cylinder head temperatures.

a) True

b) False

Answer: b

Explanation: Actually, the volumetric efficiency of an air-cooled engine is lower due to high cylinder head temperatures.

4. The design of the engines in air-cooled system becomes simpler, as no water jackets are required.

a) True

b) False

Answer: a

Explanation: None.

5. There is a danger of coolant leakage in air-cooled systems.

a) True

b) False

Answer: b

Explanation: Actually, there is no danger of coolant leakage in air-cooled systems.

6. The weight per B.P. of air-cooled engine is ___________ than that of water-cooled engine.

a) greater

b) less

c) unpredictable

d) none of the mentioned

Answer: b

Explanation: In comparison with water-cooled engine, the weight per B.P. of air-cooled engine is less.

7. The control of cooling system in air-cooled system is not easier than in water-cooled system.

a) True

b) False

Answer: b

Explanation: Actually, the control of cooling system in air-cooled system is much easier than in water-cooled system.

8. A broken fin affects much in air-cooled engine while a hole in the radiator may stop a water-cooled engine.

a) True

b) False

Answer: b

Explanation: In fact, a broken fin does not affect much in air-cooled engine while a hole in the radiator may stop a water-cooled engine.

9. In air-cooled engine, high mean cylinder temperatures mean reduced carbon deposits on the combustion chamber wall.

a) True

b) False

Answer: a

Explanation: None.

10. The warm-up performance of air-cooled engine is not better.

a) True

b) False

Answer: b

Explanation: In fact, the warm-up performance of air-cooled engine is better.

This set of IC Engine test focuses on “Engine Emissions”.

1. Pollutants are produced by the incomplete burning of the air-fuel mixture in the combustion chamber.

a) True

b) False

Answer: a

Explanation: None.

2. What are the major pollutants emitted from the exhaust due to incomplete combustion?

a) carbon monoxide

b) hydrocarbons

c) oxides of nitrogen

d) all of the mentioned

Answer: d

Explanation: The major pollutants emitted from the exhaust due to incomplete combustion are

i) carbon monoxide

ii) hydrocarbons

iii) oxides of nitrogen.

3. _____________is a colourless gas of about the same density of air.

a) Carbon monoxide

b) Hydrocarbons

c) Oxides of nitrogen

d) All of the mentioned

Answer: a

Explanation: No other gas except carbon monoxide, is a colourless gas of the same density as of air while hydrocarbons and nitrogen oxides have different densities.

4. Carbon monoxide is a poisonous gas which, when inhaled, replaces the oxygen in the blood stream so that the body’s metabolism can not function correctly.

a) True

b) False

Answer: a

Explanation: None.

5. Large amounts of CO concentrations, when breathed in, slow down physical and mental activity and produces headaches, while large concentration will kill.

a) True

b) False

Answer: b

Explanation: No, even a small amount of CO concentrations, when breathed in, slow down physical and mental activity and produces headaches, while large concentration will kill.

6. The amount of CO formed ______________ as the mixture becomes more and more rich in fuel.

a) decreases

b) increases

c) remains same

d) none of the mentioned

Answer: b

Explanation: The concentration of CO is directly proportional to the mixture, that is why the amount of CO formed increases as the mixture becomes more and more rich in fuel.

7. A small amount of CO will come out of the exhaust even when the mixture is slightly lean in fuel.

a) True

b) False

Answer: a

Explanation: None.

8. As the products cool down to exhaust temperature, a minor part of CO reacts with oxygen to form Co 2 .

a) True

b) False

Answer: b

Explanation: No, but in fact, as the products cool down to exhaust temperature, a major part of CO reacts with oxygen to form Co 2 .

9. If the combustion is complete, the only products being expelled from the exhaust would be water vapour and carbondioxide.

a) True

b) False

Answer: a

Explanation: None.

10. Air pollution is defined as an addition to our atmosphere of any material which will have a deleterious effect on life upon our planet.

a) True

b) False

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Hydrocarbon Emissions”.

1. The hydrocarbons appear due to flame quenching near the metallic walls.

a) False

b) True

Answer: b

Explanation: The main reason for hydrocarbons emission is due to flame quenching near the metallic walls.

2. The blowby HC emissions are about 30% of the total HC emission from the engine.

a) True

b) False

Answer: b

Explanation: No, actually the blowby HC emissions are about 20% of the total HC emission from the engine.

3. The intake air-fuel mixture is used to push exhaust residual out of the open exhaust port called scavenging.

a) True

b) False

Answer: a

Explanation: Scavenging is defined as the intake air-fuel mixture is used to push exhaust residual out of the open exhaust port.

4. When scavenging is done, some of the air and fuel mix with the exhaust gases and are expelled out of the cylinder before the exhaust port closes.

a) True

b) False

Answer: a

Explanation: None.

5. The exhaust of CI engines does not contain solid carbon soot particles that are generated in the fuel-rich zones within the cylinder during combustion.

a) True

b) False

Answer: b

Explanation: In fact, the exhaust of CI engines contains solid carbon soot particles that are generated in the fuel-rich zones within the cylinder during combustion.

6. A single soot particle may contain up to ____________ carbon spheres.

a) 600

b) 5000

c) 6000

d) 8000

Answer: b

Explanation: None.

7. More than 90 to 95% of carbon particles originally generated within an engine are thus converted to CO 2 and never comes out as carbon particles.

a) True

b) False

Answer: a

Explanation: When the fuel is burnt more than 90 to 95% of carbon particles originally generated within an engine are thus converted to CO 2 and never comes out as carbon particles.

8. Upper level ozone is harmful to lungs and other biological tissue.

a) True

b) False

Answer: b

Explanation: Actually, ground level ozone is harmful to lungs and other biological tissue.

9. Ozone is harmful to plants and trees and causes very heavy crop losses each year.

a) True

b) False

Answer: a

Explanation: None.

10. Diatomic oxygen is highly reactive and initiates a number of different reactions.

a) True

b) False

Answer: b

Explanation: In fact, monatomic oxygen is highly reactive and initiates a number of different reactions.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Catalytic Converters”.

1. A catalyst is a substance that accelerates a chemical reaction by lowering the energy needed for it to proceed.

a) False

b) True

Answer: b

Explanation: A catalyst is defined as a substance that accelerates a chemical reaction by lowering the energy needed for it to proceed.

2. The catalyst is consumed in the reaction and so functions indefinitely unless degraded by heat, age, contaminants or other factors.

a) True

b) False

Answer: b

Explanation: Actually, the catalyst is not consumed in the reaction and so functions indefinitely unless degraded by heat, age, contaminants or other factors.

3. Catalytic converters are chambers mounted in the flow system through which the exhaust gases pass.

a) True

b) False

Answer: a

Explanation: None.

4. The chambers present in catalytic converters does not contain catalytic material, which promotes the oxidation of the emissions contained in the exhaust flow.

a) True

b) False

Answer: b

Explanation: In fact, the chambers present in catalytic converters contain catalytic material, which promotes the oxidation of the emissions contained in the exhaust flow.

5. Catalytic converters are called three-way converters because they are used to reduce the concentration of CO. HC, and NO x in the exhaust.

a) True

b) False

Answer: a

Explanation: Catalytic converters are used to reduce the concentration of CO. HC, and NO x in the exhaust that is why they are called three-way converters.

6. Catalytic converter is usually a stainless steel container mounted along the exhaust pipe of the engine.

a) False

b) True

Answer: b

Explanation: Catalytic converter is made up of a stainless steel container mounted along the exhaust pipe of the engine.

7. Outside the container of the catalytic converter, there is a porous ceramic structure through which the exhaust gas flows.

a) True

b) False

Answer: b

Explanation: In fact inside the container of the catalytic converter, there is a porous ceramic structure through which the exhaust gas flows.

8. In most converters, the ceramic is a single honeycomb structure with many flow passages.

a) True

b) False

Answer: a

Explanation: None.

9. Volume of the ceramic structure of a converter is generally about twice the displacement volume of the engine.

a) True

b) False

Answer: b

Explanation: Actually, the volume of the ceramic structure of a converter is generally about half the displacement volume of the engine.

10. The catalyst materials most commonly used are platinum, palladium and rhodium.

a) True

b) False

Answer: a

Explanation: Platinum, palladium and rhodium are the most common materials used as catalysts.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “C.I. Engines”.

1. NO x is reduced in a CI engine by the use of EGR.

a) increased

b) reduced

c) unpredictable

d) none of the mentioned

Answer: b

Explanation: By using EGR in a CI engine, generally the emission of NO x is reduced.

2. EGR and lower combustion temperatures contribute to an ____________ in solid soot.

a) decreases

b) increases

c) same

d) none of the mentioned

Answer: b

Explanation: Frequent practice of EGR and lower combustion temperatures contribute to an increases in solid soot.

3. Platinum and palladium are two main catalyst materials used for converters on CI engines.

a) True

b) False

Answer: a

Explanation: Platinum and palladium are only the two main catalyst materials that are used for converters on CI engines.

4. Platinum and palladium catalyst promotes the removal of ____________ of the gaseous HC in the exhaust.

a) 30-80%

b) 40-90%

c) 50-100%

d) none of the mentioned

Answer: a

Explanation: In total platinum and palladium catalyst promote the removal of 30-80% of the gaseous HC in the exhaust.

5. Platinum and palladium catalyst promotes the removal of _____________ of the gaseous CO in the exhaust.

a) 30-80%

b) 40-90%

c) 50-100%

d) none of the mentioned

Answer: b

Explanation: In total platinum and palladium catalyst promote the removal of 40-90% of the gaseous HC in the exhaust.

6. Diesel fuel contains sulphur impurities, and this leads to poisoning of the catalyst materials.

a) True

b) False

Answer: a

Explanation: None.

7. Traps are filter-like system often made of ceramic in the form of a monolith or mat, or metal wire mesh.

a) True

b) False

Answer: a

Explanation: None.

8. Traps typically remove _____________ of particulates in the exhaust flow.

a) 30-80%

b) 40-90%

c) 50-100%

d) 60-90%

Answer: d

Explanation: 60-90% of particulates in the exhaust flow are removed by traps.

9. Regeneration does not consists of combusting the particulates in the excess oxygen contained in the exhaust of the lean operating CI engine.

a) True

b) False

Answer: b

Explanation: In fact, regeneration consists of combusting the particulates in the excess oxygen contained in the exhaust of the lean operating CI engine.

10. With greatly increased mixing efficiency and speeds, large regions of fuel-rich mixtures can be avoided when combustion starts.

a) True

b) False

Answer: a

Explanation: None.

This set of IC Engine Quiz focuses on “Reducing Emissions by Chemical Methods”.

1. Cyanuric acid is a ____________ solid material that sublimes in the exhaust flow.

a) high-cost

b) low-cost

c) unpredictable

d) none of the mentioned

Answer: b

Explanation: Cyanuric acid is a low-cost solid material in comparison to other chemicals that sublime in the exhaust flow.

2. ____________ are materials that absorb selected molecular compounds and catalyze chemical reactions.

a) Catalysts

b) Chromium

c) Zeolite

d) None of the mentioned

Answer: c

Explanation: Zeolite are materials that absorb selected molecular compounds and catalyze chemical reactions, while catalysts are not material and also chromium does not serve the purpose of absorption.

3. ____________ is collected during engine startup time when the catalytic converter is cold, and then later released back into the exhaust flow when the converter is hot.

a) HC

b) CO

c) CO 2

d) H 2 O

Answer: a

Explanation: Only HC is collected during engine startup time when the catalytic converter is cold, and then later released back into the exhaust flow when the converter is hot and no other gases.

4. A ____________ reduction of cold-start HC has been achieved.

a) 20%

b) 30%

c) 35%

d) 40%

Answer: c

Explanation: Till now only 35% reduction of cold-start HC has been achieved.

5. H 2 emissions occur under ____________ operating conditions.

a) rich

b) lean

c) constant

d) none of the mentioned

Answer: a

Explanation: Only H 2 emissions occur when the operating conditions are rich.

6. Exhaust gas recycle is done by ducting some of the exhaust flow back into the intake system.

a) True

b) False

Answer: a

Explanation: Exhaust gas recycle is done by ducting some of the exhaust flow back into the intake system, usually immediately after the throttle.

7. The amount of flow in EGR, can be as high as ____________ of the total intake.

a) 20%

b) 30%

c) 35%

d) 40%

Answer: b

Explanation: None.

8. EGR combines with the exhaust residual left in the cylinder from the previous cycle to effectively reduce the ____________ combustion temperature.

a) minimum

b) maximum

c) unpredictable

d) none of the mentioned

Answer: b

Explanation: EGR combines with the exhaust residual left in the cylinder from the previous cycle to effectively reduce the maximum combustion temperature as during exhaust the temperature is very high.

9. The flow rate of EGR is not controlled by the Engine management system.

a) True

b) False

Answer: b

Explanation: The flow rate of EGR is only controlled by the Engine management system.

10. ____________ in EGR results in some cycle partial burns and, in the extreme, total misfires.

a) Decrease

b) Increase

c) Consistency

d) None of the mentioned

Answer: a

Explanation: When there is an increase in EGR it results in some cycle partial burns and, in the extreme, total misfires.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Exhaust Gas Recirculation”.

1. The operation of an engine depends on the level of gasoline in the ____________ inside the carburettor.

a) tank

b) float chamber

c) ignition chamber

d) none of the mentioned

Answer: b

Explanation: The operation of an engine depends on the level of gasoline in the float chamber inside the carburettor and not in the tank or ignition chamber.

2. The evaporation of gasoline causes the loss of ____________ from the carburettor.

a) gasoline

b) water

c) vapour

d) none of the mentioned

Answer: a

Explanation: Obviously gasoline is there in the carburettor, hence evaporation of gasoline causes the loss of gasoline from the carburetor.

3. The operation of the purge control valve is taken care of by the exhaust ____________ pressure.

a) front

b) back

c) middle

d) none of the mentioned

Answer: b

Explanation: The operation of the purge control valve is taken care of by the exhaust back pressure as there is no middle or front exhaust pressure existence.

4. Under idling conditions the fuel supply is cut off to reduce the level of ____________

a) CO

b) CO 2

c) HC

d) None of the mentioned

Answer: c

Explanation: When the fuel supply is cut off under the idling conditions it is mainly to reduce the level of HC.

5. A vent valve is provided for the carburettor for the flow of ___________

a) fuel vapours

b) water

c) air

d) none of the mentioned

Answer: a

Explanation: A vent valve is provided for the carburettor for the flow of fuel vapours as only fuel is of importance in the carburettor.

6. Adsorption refers to the process of trapping of the gasoline vapours by the activated charcoal particles filled inside the canister.

a) True

b) False

Answer: a

Explanation: Adsorption is defined as the process of trapping of the gasoline vapours by the activated charcoal particles filled inside the canister.

7. Purging is the process by which the gasoline vapours are removed from the charcoal particles inside the ___________

a) float chamber

b) tank

c) canister

d) none of the mentioned

Answer: c

Explanation: Purging is the process by which the gasoline vapours are removed from the charcoal particles inside the canister and float chamber and tank are not a part of it and the charcoal particles are there in the canister.

8. A charcoal canister is used for trapping gasoline vapours.

a) True

b) False

Answer: a

Explanation: For trapping gasoline vapours, a charcoal canister is used.

9. Charcoal canister is also called ____________ canister.

a) vapour

b) carbon

c) fuel

d) none of the mentioned

Answer: b

Explanation: Charcoal is a form of carbon so Charcoal canister is also called carbon canister.

10. Fuel vapours from the float chamber of the carburettor enter into the canister through the ____________ passage.

a) right end

b) left inlet

c) left end

d) none of the mentioned

Answer: c

Explanation: The passage of fuel vapours from the float chamber of the carburettor to the canister is through the left end passage only.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Measurement and Testing”.

1. What are the basic measurement and testing parameters?

a) friction power

b) indicated power

c) brake power

d) all of the mentioned

Answer: d

Explanation: In order to achieve less cost of production, improve efficiency and power output, the important measurement and testing parameters are employed. These are

i) friction power

ii) indicated power

iii) brake power

iv) fuel consumption

v) air flow

vi) speed

vii) exhaust and coolant temperature

viii) emissions

ix) noise

x) combustion phenomenon.

2. What are the basic measurement and testing parameters?

a) fuel consumption

b) air flow

c) speed

d) all of the mentioned

Answer: d

Explanation: In order to achieve less cost of production, improve efficiency and power output, the important measurement and testing parameters are employed. These are

i) friction power

ii) indicated power

iii) brake power

iv) fuel consumption

v) air flow

vi) speed

vii) exhaust and coolant temperature

viii) emissions

ix) noise

x) combustion phenomenon.

3. _____________ is the difference between indicated and brake power of an engine.

a) Air flow

b) Emissions

c) Friction power

d) None of the mentioned

Answer: c

Explanation: The difference between the indicated and the brake power of an engine is defined as friction power, whereas air flow and emissions are related to combustion processes.

4. _____________ is also known as fuel rate extrapolation method.

a) Morse test

b) Motoring test

c) Willan’s line method

d) Retardation test

Answer: c

Explanation: The another name for Willan’s line method is fuel rate extrapolation method.

5. The internal losses in an engine are ____________

a) pumping losses

b) brake losses

c) combustion losses

d) all of the mentioned

Answer: a

Explanation: There are only two internal losses, pumping losses and friction losses. During the inlet and exhaust stroke the gaseous pressure on the piston is greater on its forward side, hence during both strokes the piston must be moved against a gaseous pressure, and this causes pumping loss.

6. In Morse test, the engine is first run at the required speed by adjusting the throttle in ___________

a) CI engine

b) SI engine

c) CI & SI engine

d) none of the mentioned

Answer: b

Explanation: While performing the morse test, the engine is first run at the required speed by adjusting the throttle in SI engine whereas the pump rack is adjusted in the CI engine.

7. The density of the fuel is dependent on temperature which can vary a wide range from ___________

a) 10 ºC to 70 ºC

b) -10 ºC to 70 ºC

c) 20 ºC to 80 ºC

d) -20 ºC to 80 ºC

Answer: b

Explanation: Generally the density of the fuel is dependent on temperature which can vary a wide range from -10 ºC to 70 ºC giving rise to a error in measurement.

8. Larger range of flow can be measured without pressure head being too ___________ in a viscous flow meter.

a) small

b) large

c) deep

d) none of the mentioned

Answer: b

Explanation: An advantage of viscous flow meter is that larger range of flow can be measured without pressure head being too small.

9. The indicated power for multi-cylinder engine will be same as that of a single cylinder engine.

a) True

b) False

Answer: b

Explanation: The indicated power for multi-cylinder engine is always greater than that of a single cylinder engine.

10. If the speed of the engine is increased, the indicated power will ____________

a) increase

b) decrease

c) remain same

d) none of the mentioned

Answer: a

Explanation: Speed is directly proportional to indicated power, so when the speed of the engine is increased, the indicated power will also increase.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Engine Power”.

1. The total power developed by combustion of fuel in the combustion chamber is called ____________

a) brake power

b) indicated power

c) mean effective pressure

d) none of the mentioned

Answer: b

Explanation: Indicated power is defined as the total power developed by combustion of fuel in the combustion chamber while brake power is defined as the power developed by an engine at the output shaft and mean effective pressure is defined as the hypothetical pressure which is thought to be acting on the piston throughout the power stroke.

2. The power developed by an engine at the output shaft is called ____________

a) brake power

b) indicated power

c) mean effective pressure

d) none of the mentioned

Answer: a

Explanation: Brake power is defined as the power developed by an engine at the output shaft while indicated power is defined as the total power developed by combustion of fuel in the combustion chamber and mean effective pressure is defined as the hypothetical pressure which is thought to be acting on the piston throughout the power stroke.

3. The hypothetical pressure which is thought to be acting on the piston throughout the power stroke is called ____________

a) brake power

b) indicated power

c) mean effective pressure

d) none of the mentioned

Answer: c

Explanation: Mean effective pressure is defined as the hypothetical pressure which is thought to be acting on the piston throughout the power stroke and brake power is defined as the power developed by an engine at the output shaft while indicated power is defined as the total power developed by combustion of fuel in the combustion chamber.

4. A 4-cylinder four stroke petrol engine develops 14.7 KW at 1000 r.p.m. The mean effective pressure is 5.5 bar. Calculate the bore and stroke of the engine, if the length of stroke is 1.5 times the bore.

a) 87.9 mm and 131.8 mm

b) 90 mm and 134 mm

c) 97.4 mm and 138 mm

d) none of the mentioned

Answer: a

Explanation: Number of cylinder, n = 4

Power developed, P = 14.7 kW

Engine speed, N = 1000 r.p.m.

Indicated mean effective pressure, P mi = 5.5 bar

Length of stroke, L = 1.5D 

For four stroke cycle, k = 1/2

Indicated power developed, I.P. = (nP mi LANk x 10)/6 kw

14.7 = (4 x 5.5 x 1.5D x (pi/4 x D 2 )x 1000 x 1/2 x 10)/6

therefore, D 3 = 0.0006806

or, D = 0.0879 or 87.9 mm

and L = 1.5 x 87.9 = 131.8 mm.

5. A single cylinder, four stroke cycle oil engine is fitted with a rope brake. The diameter of the brake wheel is 600 mm and the rope diameter is 26 mm. The dead load on the brake is 200 N and the spring balance reads 30 N. If the engine runs at 450 r.p.m., what will be the brake power of the engine?

a) 2 kW

b) 2.5 kW

c) 3 kW

d) 3.5 kW

Answer: b

Explanation: Diameter of the brake wheel, D b = 600 mm = 0.6 m

Rope diameter, d = 26 mm = 0.026 m

Dead load on the brake, W = 200 N

Spring balance reading, S = 30 N

Engine speed, N = 450 r.p.m.

Brake Power, B.P. = pi(D b + d)N)/60 x 1000

= pi x 450)/60 x 1000

= 2.5 kW.

6. The brake output per unit of piston displacement is defined as brake power.

a) True

b) False

Answer: b

Explanation: The brake output per unit of piston displacement is defined as specific output.

7. What are the types of absorption dynamo meters?

a) prony brake

b) rope brake

c) hydraulic brake

d) all of the mentioned

Answer: d

Explanation: Common forms of absorption dynamo meters are :

i) prony brake

ii) rope brake

iii) hydraulic brake

iv) fan brake

v) electrical brake dynamo meters.

8. Transmission dynamo meters are also known as ____________

a) rope brake

b) hydraulic brake

c) torque meters

d) none of the mentioned

Answer: c

Explanation: Transmission dynamo meters are also known as torque meters while rope brake and hydraulic brake are types of absorption dynamo meters.

9. The brake power is the power available ____________

a) in the engine cylinder

b) at the crank shaft

c) at the crank pin

d) none of the mentioned

Answer: b

Explanation: The power developed by an engine at the output shaft and is only available at the crank shaft.

10. The frictional power  is given by ____________

a) F.P. = B.P.-I.P.

b) F.P. = I.P.-B.P.

c) F.P. = B.P./I.P.

d) F.P. = I.P./B.P.

Answer: b

Explanation: The frictional power is the difference between indicated power and brake power. So Mathematically,

F.P = I.P.-B.P.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Engine Efficiencies”.

1. The ratio of the heat equivalent to one kW hour to the heat in fuel per B.P. hour is termed as brake thermal efficiency.

a) True

b) False

Answer: a

Explanation: Brake thermal efficiency is defined as the ratio of the heat equivalent to one kW hour to the heat in fuel per B.P. hour.

2. The ratio of the work obtained at the crankshaft in a given time to the energy supplied during the same time is called ______________

a) mechanical efficiency

b) overall efficiency

c) indicated thermal efficiency

d) volumetric efficiency

Answer: b

Explanation: Overall efficiency is the ratio of the work obtained at the crankshaft in a given time to the energy supplied during the same time while mechanical efficiency is the ratio of the brake power to the indicated power and relative efficiency is the ratio of the indicated thermal efficiency to the air standard efficiency.

3. The ratio of the brake power to the indicated power is called ______________

a) mechanical efficiency

b) overall efficiency

c) indicated thermal efficiency

d) volumetric efficiency

Answer: a

Explanation: Mechanical efficiency is the ratio of the brake power to the indicated power and relative efficiency is the ratio of the indicated thermal efficiency to the air standard efficiency whereas overall efficiency is the ratio of the work obtained at the crankshaft in a given time to the energy supplied during the same time.

4. The ratio of the indicated thermal efficiency to the air standard efficiency is known as ______________

a) mechanical efficiency

b) overall efficiency

c) relative efficiency

d) volumetric efficiency

Answer: c

Explanation: Relative efficiency is the ratio of the indicated thermal efficiency to the air standard efficiency whereas overall efficiency is the ratio of the work obtained at the crankshaft in a given time to the energy supplied during the same time and mechanical efficiency is the ratio of the brake power to the indicated power.

5. Which is the correct sequence of the decreasing order of brake thermal efficiency of the three given basic types of engines?

a) four stroke C.I. engine, four stroke S.I. engine, two stroke S.I. engine

b) four stroke S.I. engine, four stroke C.I. engine, two stroke S.I. engine

c) four stroke C.I. engine, two stroke S.I. engine, four stroke S.I. engine

d) two stroke S.I. engine, four stroke S.I. engine, four stroke C.I. engine

Answer: a

Explanation: The brake thermal efficiency of the three given basic types of engines decreases in the order four stroke C.I. engine, four stroke S.I. engine, two stroke S.I. engine.

6. The brake power of a diesel engine, keeping other parameters constant, can be increased by ______________

a) decreasing the density of intake air

b) increasing the temperature of intake air

c) increasing the pressure of intake air

d) decreasing the pressure of intake air

Answer: c

Explanation: By increasing the pressure of intake air, the brake power of a diesel engine, keeping other parameters constant, can be increased and by no other means.

7. Which one of the following event would reduce the volumetric efficiency of a vertical compression ignition engine?

a) inlet valve closing after bottom dead center

b) inlet valve closing before bottom dead center

c) inlet valve opening before top dead center

d) exhaust valve closing after top dead center

Answer: b

Explanation: Volumetric efficiency of a vertical compression ignition engine is reduced by closing inlet valve before bottom dead center.

8. As compared to air standard cycle, in actual working, the effect of variation in specific heats is to ______________

a) increase maximum pressure and maximum temperature

b) decrease maximum pressure and maximum temperature

c) increase maximum pressure and decrease maximum temperature

d) decrease maximum pressure and increase maximum temperature

Answer: b

Explanation: In actual working, as compared to air standard cycle, the effect of variation in specific heats is to decrease maximum pressure and maximum temperature.

9. The ratio of the volume of charge admitted at N.T.P. to the swept volume of the piston is called ______________

a) mechanical efficiency

b) overall efficiency

c) relative efficiency

d) volumetric efficiency

Answer: d

Explanation: Volumetric efficiency is the ratio of the volume of charge admitted at N.T.P. to the swept volume of the piston while mechanical efficiency is the ratio of the brake power to the indicated power and relative efficiency is the ratio of the indicated thermal efficiency to the air standard efficiency whereas overall efficiency is the ratio of the work obtained at the crankshaft in a given time to the energy supplied during the same time.

10. The overall efficiency is defined as the ratio of the work obtained at the crankshaft in a given time to the energy supplied during the same time.

a) True

b) False

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Engine Performance Characteristics”.

1. For which of the following engines a prony brake is used to measure brake power?

a) single cylinder engine

b) low speed engine

c) low power engine

d) variable speed engine

Answer: d

Explanation: Prony brake is used to measure the brake power of variable speed engines.

2. What does scavenging air mean?

a) Burnt air containing combustion products

b) Air sent under compression

c) Forced air for cooling the engine cylinder

d) Air used for forcing the burnt gases out of cylinder during the exhaust period

Answer: d

Explanation: Scavenging air is defined as the air used for forcing the burnt gases out of cylinder during the exhaust period.

3. ____________ is the basic requirement of a good combustion chamber.

a) Low volumetric efficiency

b) High compression ratio

c) Low compression ratio

d) High power output and high thermal efficiency

Answer: d

Explanation: The basic requirement of a good combustion chamber are:

i) High power output

ii) High thermal efficiency and low specific fuel consumption

iii) smooth engine operation

iv) reduced exhaust pollutants.

4. ____________ is the method of governing used in petrol engine.

a) Quality governing

b) Hit and mass governing

c) Quantity governing

d) All of the mentioned

Answer: a

Explanation: Quality governing is generally used in petrol engines as the quantity of air -fuel mixture flowing into the cylinder is varied accordingly and this may be done by decreasing the lift of the inlet valve or by throttling the mixture before it is made to enter the engine cylinder.

5. Hunting occurs due to which of the following?

a) Faulty governor

b) Poor control by the governor

c) Over control by the governor

d) Bad engine design

Answer: b

Explanation: Hunting occurs due to load variation and this is only when the governor is not controlled properly.

6. Maximum torque is generated by an engine when ______________

a) it runs at lowest speed

b) it develops maximum power

c) it consumes maximum fuel

d) it runs at maximum speed

Answer: a

Explanation: Maximum torque is generated by an engine when it runs at lowest speed while maximum power is developed when the engine rums at its maximum speed.

7. With an increase of the number of cylinders in a multicylinder engine the power to weight ratio ______________

a) decreases

b) increases

c) remains unaffected

d) none of the mentioned

Answer: c

Explanation: The power to weight ratio remains unaffected even after if the number of cylinders in a multicylinder is increased because as the number of cylinders increases, torque is smoother and less flywheel mass is needed.

8. Radiator tubes are generally made of______________

a) cast iron

b) steel

c) plastics

d) brass

Answer: d

Explanation: Brass is used to make radiator pipes due to its heat resistance capacities.

9. Automobile gears are generally made of ______________

a) cast iron

b) stainless steel

c) alloy steel

d) mild steel

Answer: c

Explanation: Steel mixed with copper, zinc and tin is used to make gears in automobiles.

10. ____________ is used to check the state of charge of a battery.

a) Battery charger

b) Hygrometer

c) Hydrometer

d) Battery eliminator

Answer: a

Explanation: Battery charger is used to check the state of charge of a battery while hygrometer is used to check the air humidity and hydrometer is used to check the specific gravity.

This set of IC Engine Mcqs focuses on “Methods Of Improving Engine Performance”.

1. The extent to which the measured value deviates from the true value of the measurand is?

a) precision

b) accuracy

c) resolution

d) none of the mentioned

Answer: b

Explanation: Accuracy is the extent to which the measured value deviates from the true value of the measurand while precision is the degree of reproducibility among several independent measurements of the same true value under reference conditions and resolution is the magnitude of discernible or detectable output changes as the measurand is continuously varied over the range.

2. The degree of reproducibility among several independent measurements of the same true value under reference conditions is?

a) precision

b) accuracy

c) resolution

d) none of the mentioned

Answer: a

Explanation: Precision is the degree of reproducibility among several independent measurements of the same true value under reference conditions and resolution is the magnitude of discernible or detectable output changes as the measurand is continuously varied over the range while accuracy is the extent to which the measured value deviates from the true value of the measurand.

3. ____________ is the ability of a measuring device to reproduce output readings when the same measurand value is applied to it repeatedly under the same environmental conditions and in the same direction.

a) Precision

b) Repeatability

c) Accuracy

d) None of the mentioned

Answer: b

Explanation: Repeatability is the ability of a measuring device to reproduce output readings when the same measurand value is applied to it repeatedly under the same environmental conditions and in the same direction and accuracy is the extent to which the measured value deviates from the true value of the measurand while precision is the degree of reproducibility among several independent measurements of the same true value under reference conditions.

4. ____________ is a measure of the probability that a measuring device will continue to perform within specified limits of error over a specified length of time under specified conditions.

a) Reliability

b) Repeatability

c) Accuracy

d) None of the mentioned

Answer: a

Explanation: Reliability is a measure of the probability that a measuring device will continue to perform within specified limits of error over a specified length of time under specified conditions while repeatability is the ability of a measuring device to reproduce output readings when the same measurand value is applied to it repeatedly under the same environmental conditions and in the same direction and accuracy is the extent to which the measured value deviates from the true value of the measurand.

5. ____________ is the magnitude of discernible or detectable output changes as the measurand is continuously varied over the range.

a) Reliability

b) Repeatability

c) Resolution

d) None of the mentioned

Answer: c

Explanation: Resolution is the magnitude of discernible or detectable output changes as the measurand is continuously varied over the range and reliability is a measure of the probability that a measuring device will continue to perform within specified limits of error over a specified length of time under specified conditions while repeatability is the ability of a measuring device to reproduce output readings.

6. ____________ is the time required for the output of measuring device to reach a specified percentage of its final value as a result of a step change of measurand.

a) Response time

b) Repeatability

c) Resolution

d) None of the mentioned

Answer: a

Explanation: Response time is the time required for the output of measuring device to reach a specified percentage of its final value as a result of a step change of measurand while resolution is the magnitude of discernible or detectable output changes as the measurand is continuously varied over the range.

7. ____________ is the algebraic difference between the maximum and minimum limits of the range.

a) Response time

b) Repeatability

c) Span

d) None of the mentioned

Answer: c

Explanation: Span is the algebraic difference between the maximum and minimum limits of the range while reliability is a measure of the probability that a measuring device will continue to perform within specified limits of error over a specified length of time under specified conditions and response time is the time required for the output of measuring device to reach a specified percentage of its final value as a result of a step change of measurand.

8. ____________ is the ability of a measuring device to retain its repeatability and other characteristics throughout its specified operating life and storage life.

a) Response time

b) Stability

c) Span

d) None of the mentioned

Answer: b

Explanation: Stability is the ability of a measuring device to retain its repeatability and other characteristics throughout its specified operating life and storage life while span is the algebraic difference between the maximum and minimum limits of the range.

9. ____________ is the measurand values over which a measuring device is intended to measure, specified by upper or lower limits.

a) Range

b) Stability

c) Span

d) None of the mentioned

Answer: a

Explanation: Range is the measurand values over which a measuring device is intended to measure, specified by upper or lower limits and stability is the ability of a measuring device to retain its repeatability and other characteristics throughout its specified operating life and storage life while span is the algebraic difference between the maximum and minimum limits of the range.

10. ____________ is the time required for the output of a measuring device to rise from 10% to 90% of its final value.

a) Range

b) Rise time

c) Span

d) None of the mentioned

Answer: b

Explanation: Rise time is the time required for the output of a measuring device to rise from 10% to 90% of its final value and range is the measurand values over which a measuring device is intended to measure, specified by upper or lower limits.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Engine Management Systems”.

1. Which of the following is the main aim of an engine management system to achieve?

a) high reliability and durability with lowest possible initial cost

b) high power output and torque

c) low levels of gaseous and particulate emissions

d) all of the mentioned

Answer: d

Explanation: The main aims of an engine management system is to achieve

i) high reliability and durability with lowest possible initial cost

ii) high power output and torque

iii) low levels of gaseous and particulate emissions

iv) low fuel consumption

v) low noise levels and vibrations.

2. What are the important parameters in a gasoline engine that can be controlled?

a) air-fuel ratio

b) mixture distribution between cylinders

c) ignition timing

d) all of the mentioned

Answer: d

Explanation: The important parameters in a gasoline engine that can be controlled are

i) air-fuel ratio

ii) mixture distribution between cylinders

iii) ignition timing

iv) injection timing of the fuel

v) idle speed.

3. Hall effect pickup use ______________

a) inductive transducers

b) potentiometers

c) thermistors

d) semiconductors

Answer: d

Explanation: Hall effect pickup is a transducer that varies its output voltage in response to a magnetic field. Hall effect sensors are used for proximity switching, positioning, speed detection, and current sensing application and thus it uses semiconductor.

4. LVDT is used to measure ______________

a) crank angle

b) engine speed

c) large displacements

d) gas temperature

Answer: c

Explanation: To measure large displacements, LVDT is used.

5. What is the disadvantage of the piezoelectric pressure pickup?

a) it can only give pressure difference

b) it can measure only low pressure

c) it is not suitable for dynamic measurement

d) has too much sensitivity

Answer: a

Explanation: By using piezoelectric pressure pickup only the pressure difference can be measured and not the low pressure.

6. Thermistors are desirable because of their ______________

a) linear output

b) large temperature coefficient

c) suitability for high temperature

d) none of the mentioned

Answer: b

Explanation: Only thermistors have the property to give large temperature coefficients.

7. Seebeck effect is used in ______________

a) thermistors

b) thermocouples

c) rtd

d) hot-wire sensor

Answer: b

Explanation: Seebeck effect is a property in thermocouples and not in thermistors and RTD.

8. Hot-wire sensors are used for the measurement of ______________

a) temperature

b) pressure

c) mass flow rate

d) smoke intensity

Answer: c

Explanation: Only mass flow rate is measured by using hot-wire sensors.

9. Knock sensors use ______________

a) thermistors

b) thermocouples

c) piezoelectric pickup

d) flap type sensors

Answer: c

Explanation: In piezoelectric pickup knock sensors are used while seebeck effect is used in thermocouples.

10. Catalytic converters use lambda sensors to keep ______________

a) exhaust temperature constant

b) exhaust pressure constant

c) excess air ratio within a range

d) flow rate of air constant

Answer: c

Explanation: Only lambda sensors are used in catalytic converters to keep excess air ratio within a range.

This set of IC Engine Multiple Choice Questions & Answers focuses on “Position Displacement and Speed Sensing”.

1. The amount of output measured beyond the final steady output value in response to a step change in the measurand is called?

a) range

b) overshoot

c) span

d) none of the mentioned

Answer: b

Explanation: The amount of output measured beyond the final steady output value in response to a step change in the measurand is called overshoot and range is the measurand values over which a measuring device is intended to measure, specified by upper or lower limits.

2. ____________ is the maximum deviation of any calibration point, obtained for either increasing or decreasing input, obtained for either increasing or decreasing input, from the best fit straight line having overall minimum deviation.

a) Linearity

b) Rise time

c) Span

d) None of the mentioned

Answer: a

Explanation: Linearity is the maximum deviation of any calibration point, obtained for either increasing or decreasing input, obtained for either increasing or decreasing input, from the best fit straight line having overall minimum deviation and rise time is the time required for the output of a measuring device to rise from 10% to 90% of its final value and span is the algebraic difference between the maximum and minimum limits of the range.

3. ____________ is the maximum difference in output for the same measurand value within the range of a measuring device, one obtained by increasing from zero and other by decreasing from a higher value of the measurand.

a) Linearity

b) Hysteresis

c) Span

d) None of the mentioned

Answer: b

Explanation: Hysteresis is the maximum difference in output for the same measurand value within the range of a measuring device, one obtained by increasing from zero and other by decreasing from a higher value of the measurand and linearity is the maximum deviation of any calibration point, obtained for either increasing or decreasing input, obtained for either increasing or decreasing input, from the best fit straight line having overall minimum deviation.

4. The algebraic difference between the indicated or observed value and the true value of the measurand is the ______________

a) range

b) overshoot

c) error

d) none of the mentioned

Answer: c

Explanation: The algebraic difference between the indicated or observed value and the true value of the measurand is the error and the amount of output measured beyond the final steady output value in response to a step change in the measurand is called overshoot.

5. The random changes in output under constant measurand and normal operating conditions is called the ______________

a) range

b) drift

c) error

d) none of the mentioned

Answer: b

Explanation: The random changes in output under constant measurand and normal operating conditions is called the drift and The algebraic difference between the indicated or observed value and the true value of the measurand is called the error.

6. _______________ is a test during which standard values of measurand are applied to the measuring device and the corresponding output readings are compared with the standard values.

a) Linearity

b) Hysteresis

c) Calibration

d) None of the mentioned

Answer: c

Explanation: Calibration is a test during which standard values of measurand are applied to the measuring device and the corresponding output readings are compared with the standard values and hysteresis is the maximum difference in output for the same measurand value within the range of a measuring device, one obtained by increasing from zero and other by decreasing from a higher value of the measurand and linearity is the maximum deviation of any calibration point, obtained for either increasing or decreasing input, obtained for either increasing or decreasing input, from the best fit straight line having overall minimum deviation.

7. ________________ is the time during which a device or system is insensitive, after receiving a stimulus, to any other impulse or stimulus.

a) Dead time

b) Hysteresis

c) Calibration

d) None of the mentioned

Answer: a

Explanation: Dead time is the time during which a device or system is insensitive, after receiving a stimulus, to any other impulse or stimulus while calibration is a test during which standard values of measurand are applied to the measuring device and the corresponding output readings are compared with the standard values and hysteresis is the maximum difference in output for the same measurand value within the range of a measuring device, one obtained by increasing from zero and other by decreasing from a higher value of the measurand.

8. ______________ is the utilization of supplemental device, materials, or processes to minimize known sources or error.

a) Dead time

b) Compensation

c) Calibration

d) None of the mentioned

Answer: b

Explanation: Compensation is the utilization of supplemental device, materials, or processes to minimize known sources or error while dead time is the time during which a device or system is insensitive, after receiving a stimulus, to any other impulse or stimulus while calibration is a test during which standard values of measurand are applied to the measuring device and the corresponding output readings are compared with the standard values.

9. A calibration during which the measurement varies with time in a specified manner and the output is recorded as a function of time is called ______________

a) dynamic calibration

b) drift

c) error

d) none of the mentioned

Answer: a

Explanation: A calibration during which the measurement varies with time in a specified manner and the output is recorded as a function of time is called dynamic calibration while he random changes in output under constant measurand and normal operating conditions is called the drift and The algebraic difference between the indicated or observed value and the true value of the measurand is called the error.

10. Characteristics of a measuring device which relate to its response to variations of the measurand with time is called ______________

a) dynamic calibration

b) dynamic characteristics

c) error

d) none of the mentioned

Answer: b

Explanation: Characteristics of a measuring device which relate to its response to variations of the measurand with time are called dynamic characteristics while a calibration during which the measurement varies with time in a specified manner and the output is recorded as a function of time is called dynamic calibration.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Measurement of Pressure”.

1. _____________ is the impedance presented to the excitation source, measured across the excitation terminals of a measuring device.

a) Input impedance

b) Output impedance

c) Measurand

d) None of the mentioned

Answer: a

Explanation: Input impedance is the impedance presented to the excitation source, measured across the excitation terminals of a measuring device while output impedance is the impedance across the output terminals of a measuring device presented by it to the associated external circuitry.

2. _____________ is the impedance across the output terminals of a measuring device presented by it to the associated external circuitry.

a) Input impedance

b) Output impedance

c) Measurand

d) None of the mentioned

Answer: b

Explanation: Output impedance is the impedance across the output terminals of a measuring device presented by it to the associated external circuitry while input impedance is the impedance presented to the excitation source, measured across the excitation terminals of a measuring device.

3. _____________ is the physical quantity, property, or condition that is to be measured.

a) Input impedance

b) Output impedance

c) Measurand

d) None of the mentioned

Answer: c

Explanation: Measurand is the physical quantity, property, or condition that is to be measured and output impedance is the impedance across the output terminals of a measuring device presented by it to the associated external circuitry while input impedance is the impedance presented to the excitation source, measured across the excitation terminals of a measuring device.

4. The maximum magnitude of measurand that can be applied to a measuring device without causing a change in performance beyond specified tolerance is called?

a) overload

b) zero drift

c) warm up period

d) none of the mentioned

Answer: a

Explanation: The maximum magnitude of measurand that can be applied to a measuring device without causing a change in performance beyond specified tolerance is called overload while a change in output over a specified period of time at specified ambient conditions with input held constant is called zero drift.

5. A change in output over a specified period of time at specified ambient conditions with input held constant is called?

a) overload

b) zero drift

c) warm up period

d) none of the mentioned

Answer: b

Explanation: A change in output over a specified period of time at specified ambient conditions with input held constant is called zero drift and warm up period is the period of time, starting with the application of power to the measuring device, required to assure that it will perform within specified tolerance.

6. _____________ is the period of time, starting with the application of power to the measuring device, required to assure that it will perform within specified tolerance.

a) Overload

b) Zerodrift

c) Warm up period

d) None of the mentioned

Answer: c

Explanation: Warm up period is the period of time, starting with the application of power to the measuring device, required to assure that it will perform within specified tolerance and The maximum magnitude of a measurand that can be applied to a measuring device without causing a change in performance beyond specified tolerance is called overload while a change in output over a specified period of time at specified ambient conditions with input held constant is called zero drift.

7. _____________ is a device which provides a usable output in response to a specified measurand.

a) Zero drift

b) Transducer

c) Linearity

d) None of the mentioned

Answer: b

Explanation: Transducer is a device which provides a usable output in response to a specified measurand while linearity is the maximum deviation of any calibration point, obtained for either increasing or decreasing input, obtained for either increasing or decreasing input, from the best fit straight line having overall minimum deviation and change in output over a specified period of time at specified ambient conditions with input held constant is called zerodrift.

8. ______________ is the smallest change in the measurand that produces a detectable change in the transducer output.

a) Zero drift

b) Threshold

c) Linearity

d) None of the mentioned

Answer: b

Explanation: Threshold is the smallest change in the measurand that produces a detectable change in the transducer output while linearity is the maximum deviation of any calibration point, obtained for either increasing or decreasing input, obtained for either increasing or decreasing input, from the best fit straight line having overall minimum deviation and change in output over a specified period of time at specified ambient conditions with input held constant is called zerodrift.

9. The time required for the output of a transducer to rise to 63.2% of its final value as a result of a step change in the measurand is called?

a) zero drift

b) threshold

c) time constant

d) none of the mentioned

Answer: c

Explanation: The time required for the output of a transducer to rise to 63.2% of its final value as a result of a step change in the measurand is called time constant while threshold is the smallest change in the measurand that produces a detectable change in the transducer output.

10. An excitation and amplification system for use with transducers is termed as ______________

a) signal controlling

b) threshold

c) time constant

d) none of the mentioned

Answer: a

Explanation: An excitation and amplification system for use with transducers is termed as a signal controlling The time required for the output of a transducer to rise to 63.2% of its final value as a result of a step change in the measurand is called time constant while threshold is the smallest change in the measurand that produces a detectable change in the transducer output.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Measurement of Temperature”.

1. The conditions of the medium surrounding the measuring device is called ______________

a) analog signal

b) instability

c) ambient condition

d) none of the mentioned

Answer: c

Explanation: The conditions of the medium surrounding the measuring device is called ambient condition while a tendency of a system to break into unwanted oscillation is instability.

2. A line midway between two parallel straight lines close together and enclosing all output versus measurand values, on a calibration curve is termed as ______________

a) analog signal

b) best fit straight line

c) ambient condition

d) none of the mentioned

Answer: b

Explanation: A line midway between two parallel straight lines close together and enclosing all output versus measurand values, on a calibration curve is termed as best fit straight line while the conditions of the medium surrounding the measuring device is called ambient condition.

3. A mechanical element generally cylindrical shape with cylindrical walls having deep convolutions are the ____________

a) bellows

b) best fit straight line

c) ambient condition

d) none of the mentioned

Answer: a

Explanation: A mechanical element generally cylindrical shape with cylindrical walls having deep convolutions are the bellows and a line midway between two parallel straight lines close together and enclosing all output versus measurand values, on a calibration curve is termed as best fit straight line while the conditions of the medium surrounding the measuring device is called ambient condition.

4. A pressure sensing element consisting of a twisted or curved tube of non-circular cross-section which tends to get straightened on the application of internal pressure is the ____________

a) bellows

b) best fit straight line

c) bourdon tube

d) none of the mentioned

Answer: c

Explanation: A pressure sensing element consisting of a twisted or curved tube of non-circular cross-section which tends to get straightened on the application of internal pressure is the bourdon tube while a mechanical element generally cylindrical shape with cylindrical walls having deep convolutions are the bellows and a line midway between two parallel straight lines close together and enclosing all output versus measurand values, on a calibration curve is termed as best fit straight line while the conditions of the medium surrounding the measuring device is called ambient condition.

5. _____________ is the range of values over which a measured variable can change without affecting the output.

a) Dead band

b) Capsule

c) Diaphragm

d) None of the mentioned

Answer: a

Explanation: Dead band is the range of values over which a measured variable can change without affecting the output while the diaphragm is the range of values over which a measured variable cannot change without affecting the output.

6. _____________ is a sensing element consisting of a thin flexible circular plate which can be actuated by a pressure differential applied across the plate.

a) Dead band

b) Capsule

c) Diaphragm

d) None of the mentioned

Answer: c

Explanation: Diaphragm is a sensing element consisting of a thin flexible circular plate which can be actuated by a pressure differential applied across the plate and capsule is a pressure sensing element consisting of two corrugated metallic diaphragms joined along their circumference.

7. _____________ is the rating applicable to a specified operation for a specified uninterrupted length of time.

a) Dead band

b) Continuous rating

c) Diaphragm

d) None of the mentioned

Answer: b

Explanation: Continuous rating is the rating applicable to a specified operation for a specified uninterrupted length of time diaphragm is a sensing element consisting of a thin flexible circular plate which can be actuated by a pressure differential applied across the plate.

8. _____________ is a pressure sensing element consisting of two corrugated metallic diaphragms joined along their circumference.

a) Dead band

b) Capsule

c) Diaphragm

d) None of the mentioned

Answer: b

Explanation: Capsule is a pressure sensing element consisting of two corrugated metallic diaphragms joined along their circumference and dead band is the range of values over which a measured variable can change without affecting the output.

9. _____________ is the rating applicable to a specified operation over a stated number of time intervals of a specified duration.

a) Dead band

b) Capsule

c) Intermittent rating

d) None of the mentioned

Answer: c

Explanation: Intermittent rating is the rating applicable to a specified operation over a stated number of time intervals of specified duration while capsule is a pressure sensing element consisting of two corrugated metallic diaphragms joined along their circumference and dead band is the range of values over which a measured variable can change without affecting the output.

10. _____________ is the complex impedance presented to the output terminals of a transducer by the associated circuitry or load.

a) Lead impedance

b) Capsule

c) Intermittent rating

d) None of the mentioned

Answer: a

Explanation: Lead impedance is the complex impedance presented to the output terminals of a transducer by the associated circuitry or load while intermittent rating is the rating applicable to a specified operation over a stated number of time intervals of the specified duration.

This set of IC Engine online test focuses on “Intake Air Flow Measurement”.

1. What is the ratio of the difference between measured value and true value to the true value of the measurand?

a) transient

b) relative error

c) dead zone

d) none of the mentioned

Answer: b

Explanation: The ratio of the difference between measured value and true value to the true value of the measurand is relative error while signal varying non-cyclically with time and becomes zero after a certain period of time is transient.

2. Signal varying cyclically with time or repeating itself after a constant interval is ____________

a) periodic

b) varying

c) dead zone

d) none of the mentioned

Answer: a

Explanation: Signal varying cyclically with time or repeating itself after a constant interval is periodic while the largest change of output quantity for which there is no output of the instrument is the dead zone.

3. Signal varying non-cyclically with time and becomes zero after a certain period of time is ___________

a) periodic

b) transient

c) dead zone

d) none of the mentioned

Answer: b

Explanation: Signal varying non-cyclically with time and becomes zero after a certain period of time is transient and signal varying cyclically with time or repeating itself after a constant interval is periodic while the largest change of output quantity for which there is no output of the instrument is the dead zone.

4. Signal varying randomly with time, with no definite period and amplitude is _____________

a) periodic

b) transient

c) random

d) none of the mentioned

Answer: c

Explanation: Signal varying randomly with time, with no definite period and amplitude is random while signal varying non-cyclically with time and becomes zero after a certain period of time is transient.

5. _____________ is the output response of an instrument to various types of dynamic input signals obtained by solving its governing equation relating output and input.

a) Periodic

b) Dynamic response

c) Random

d) None of the mentioned

Answer: b

Explanation: Dynamic response is the output response of an instrument to various types of dynamic input signals obtained by solving its governing equation relating output and input while signal varying randomly with time, with no definite period and amplitude is random.

6. _____________ is the variation of output signal against frequency.

a) Frequency response

b) Dynamic response

c) Random

d) None of the mentioned

Answer: a

Explanation: Frequency response is the variation of output signal against frequency while dynamic response is the output response of an instrument to various types of dynamic input signals obtained by solving its governing equation relating output and input while signal varying randomly with time, with no definite period and amplitude is random.

7. _____________ is an instrument having no dynamic error and no time lag of measurement.

a) Frequency response

b) Dynamic response

c) First order response

d) None of the mentioned

Answer: c

Explanation: First order response is an instrument having no dynamic error and no time lag of measurement and frequency response is the variation of output signal against frequency while dynamic response is the output response of an instrument to various types of dynamic input signals obtained by solving its governing equation relating output and input.

8. _____________ is the technique of analysis of the measured data for evaluating errors and deviations.

a) Frequency response

b) Static analysis

c) First order response

d) None of the mentioned

Answer: b

Explanation: Static analysis is the technique of analysis of the measured data for evaluating errors and deviations and first order response is an instrument having no dynamic error and no time lag of measurement and frequency response is the variation of output signal against frequency.

9. _____________ is the time required by a measurement system to begin to respond to a change in the measurand.

a) Dead time

b) Static analysis

c) First order response

d) None of the mentioned

Answer: a

Explanation: Dead time is the time required by a measurement system to begin to respond to a change in the measurand while static analysis is the technique of analysis of the measured data for evaluating errors and deviations and first order response is an instrument having no dynamic error and no time lag of measurement.

10. The largest change of output quantity for which there is no output of the instrument is the ____________

a) dead time

b) dead zone

c) first order response

d) none of the mentioned

Answer: b

Explanation: The largest change of output quantity for which there is no output of the instrument is the dead zone and dead time is the time required by a measurement system to begin to respond to a change in the measurand.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Supercharging”.

1. Supercharging of S.I engines is employed only for aircraft and racing car engines.

a) True

b) False

Answer: a

Explanation: Supercharging requires when speed is taken into consideration so, supercharging of S.I engines is employed only for aircraft and racing car engines.

2. ____________ in supercharging pressure increases the tendency to detonate and pre-ignite.

a) Decrease

b) Increase

c) Unpredictable

d) None of the mentioned

Answer: a

Explanation: Detonation and pre-ignition are increased by an increase in supercharging pressure.

3. The supercharged petrol engines have a lower fuel consumption than naturally aspirated engines.

a) True

b) False

Answer: b

Explanation: Actually, supercharged petrol engines have a greater fuel consumption than naturally aspirated engines.

4. Increased intake pressure and temperature reduces ignition delay and decreases flame speed.

a) True

b) False

Answer: b

Explanation: In fact, increased intake pressure and temperature reduce ignition delay and increases flame speed.

5. The increased flame speeds make the petrol engine more sensitive to fuel-air ratio and engine cannot run on strong mixtures without knock.

a) True

b) False

Answer: b

Explanation: Actually, the increased flame speeds make the petrol engine more sensitive to fuel-air ratio and engine cannot run on weak mixtures without knock.

6. Rich mixtures are used to control detonation, which further increases the specific fuel consumption of the engine.

a) True

b) False

Answer: a

Explanation: None.

7. The ignition timings and thermal load on the engine affect the knock limit of CI engine.

a) True

b) False

Answer: b

Explanation: No, in fact the ignition timings and thermal load on the engine affect the knock limit of SI engine.

8. The ignition must be retarded at high intake pressure and temperature.

a) True

b) False

Answer: a

Explanation: None.

9. The power developed by the turbocharger is not sufficient to drive the compressor, and overcome its mechanical friction.

a) True

b) False

Answer: b

Explanation: In fact, the power developed by the turbocharger is sufficient to drive the compressor, and overcome its mechanical friction.

10. The loss in piston work due to the early opening of the exhaust valve is less than offset by better charging and scavenging of the engine.

a) True

b) False

Answer: b

Explanation: No, in fact, the loss in piston work due to the early opening of the exhaust valve is more than offset by better charging and scavenging of the engine.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Effects Of Supercharging”.

1. The knock limit is dependent upon ___________

a) the type of fuel used

b) mixture ratio

c) spark advance

d) all of the mentioned

Answer: d

Explanation: The knock limit is dependent upon the following factors

i) the type of fuel used

ii) mixture ratio

iii) spark advance

iv) design feature of the engine.

2. For volatile petroleum fuels of high octane number, the knocking is reduced at _____________ mixture.

a) very rich

b) very lean

c) equal

d) none of the mentioned

Answer: a

Explanation: It has been observed that for volatile petroleum fuels of high octane number, the knocking is reduced at very rich mixture and reduces pre-ignition at very lean mixture.

3. For volatile petroleum fuels of high octane number, pre-ignition is reduced at _____________ mixture.

a) very rich

b) very lean

c) equal

d) none of the mentioned

Answer: b

Explanation: For volatile petroleum fuels of high octane number, pre-ignition is reduced at very lean mixture while the knocking is reduced at very rich mixture.

4. In alcoholic fuels the knock is reduced at _____________ mixtures.

a) rich

b) lean

c) equal

d) none of the mentioned

Answer: a

Explanation: In alcoholic fuels the knock is reduced at rich mixtures because of the cooling effect of high latent heat of the fuel.

5. A slight ___________ in lean mixture makes the engine operation irregular and intermittent.

a) increase

b) reduction

c) heat

d) none of the mentioned

Answer: b

Explanation: Very lean and very rich mixtures give non-knocking operations, and as a reason a slight reduction in lean mixture makes the engine operation irregular and intermittent.

6. The ignition timings and thermal load on the engine affect the knock limit of _____________ engine.

a) SI

b) CI

c) SI & CI

d) None of the mentioned

Answer: a

Explanation: The ignition timings and thermal load on the engine affect the knock limit of SI engine while there is no such case in CI engine.

7. The pressure of supercharger used is ___________

a) 1.0 to 1.3 bar

b) 1.2 to 1.4 bar

c) 1.3 to 1.5 bar

d) none of the mentioned

Answer: c

Explanation: In general, the supercharger pressure of 1.3 to 1.5 bar is used, which corresponds to about 30 to 50 percent supercharging.

8. In CI engine, the power developed by the turbocharger is sufficient to drive the compressor, and overcome mechanical friction.

a) True

b) False

Answer: a

Explanation: In CI engine there is no use of superchargers, as in the case of SI engines, so the power from turbocharger is sufficient to drive the compressor and overcome mechanical friction.

9. Increase in pressure and temperature of the intake air increases significantly delay and rate of pressure.

a) True

b) False

Answer: b

Explanation: Increase in pressure and temperature of the intake air reduces significantly delay and rate of pressure.

10. The speed range of turbocharger is from ___________

a) 10000 to 20000 r.p.m

b) 20000 to 30000 r.p.m

c) 30000 to 40000 r.p.m

d) none of the mentioned

Answer: b

Explanation: The speed range of the turbocharger is from 20000 to 30000 r.p.m.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Turbocharging”.

1. Turbochargers are centrifugal compressors driven by the exhaust gas turbines.

a) True

b) False

Answer: a

Explanation: None.

2. A typical petrol engine may harness up to ____________ of the energy contained in the fuel supplied.

a) 20%

b) 30%

c) 40%

d) none of the mentioned

Answer: b

Explanation: Up to 30% of the energy contained in the fuel supplied is harnessed in a typical petrol engine.

3. ____________ of fuel energy is wasted as heat energy to friction, pumping and dynamic movement.

a) 7%

b) 9%

c) 16%

d) 38%

Answer: a

Explanation: Approximately 7% of fuel energy is wasted as heat energy to friction, pumping and dynamic movement and 9% of fuel energy is wasted as heat energy to surrounding air.

4. ____________ of fuel energy is wasted as heat energy to surrounding air.

a) 7%

b) 9%

c) 16%

d) 38%

Answer: b

Explanation: 9% of fuel energy is wasted as heat energy to surrounding air while 16% of fuel energy is wasted as heat energy to engine’s coolant system.

5. ____________ of fuel energy is wasted as heat energy to engine’s coolant system.

a) 7%

b) 9%

c) 16%

d) 38%

Answer: c

Explanation: 16% of fuel energy is wasted as heat energy to engine’s coolant system while approximately 7% of fuel energy is wasted as heat energy to friction, pumping and dynamic movement and 9% of fuel energy is wasted as heat energy to surrounding air.

6. ____________ of fuel energy is wasted as heat energy to outgoing exhaust gases.

a) 7%

b) 9%

c) 16%

d) 38%

Answer: d

Explanation: 38% of fuel energy is wasted as heat energy to outgoing exhaust gases and 16% of fuel energy is wasted as heat energy to engine’s coolant system while approximately 7% of fuel energy is wasted as heat energy to friction, pumping and dynamic movement and 9% of fuel energy is wasted as heat energy to surrounding air.

7. The turbocharger relies solely on extracting up to a third of the wasted energy passing out from the engine’s cylinders to impart power to the turbine wheel and compressor wheel assembly.

a) True

b) False

Answer: a

Explanation: The turbocharger relies solely on extracting up to a third of the wasted energy passing out from the engine’s cylinders to impart power to the turbine wheel and compressor wheel assembly.

8. Turbocharged engines produce lower cylinder volumetric efficiencies compared with the normally aspirated induction systems.

a) True

b) False

Answer: b

Explanation: In fact, turbocharged engines produce higher cylinder volumetric efficiencies compared with the normally aspirated induction systems.

9. The compression of the charge entering the cells of the impeller depends upon the centrifugal force effect which decreases with the square of the rotational speed of the impeller wheel.

a) True

b) False

Answer: b

Explanation: In fact, the compression of the charge entering the cells of the impeller depends upon the centrifugal force effect which increases with the square of the rotational speed of the impeller wheel.

10. When the engine is suddenly accelerated there will be a small time delay before the extra energy discharged into the turbine housing volute can speed up the turbine wheel.

a) True

b) False

Answer: a

Explanation: Yes, when the engine is suddenly accelerated there will be a small time delay before the extra energy discharged into the turbine housing volute can speed up the turbine wheel.

This set of IC Engine online quiz focuses on “Terminologies and Definitions”.

1. Crankcase explosion in I.C. engine usually occurs as __________

a) first a mild explosion followed by a big explosion

b) first a big explosion followed by a mild explosion

c) both mild and big explosions occur simultaneously

d) never occurs

Answer: a

Explanation: None.

2. The ____________ volume created in the cylinder during the operation of the engine is filled with the working fluid.

a) constant

b) varying

c) any one of the mentioned

d) none of the mentioned

Answer: b

Explanation: None.

3. ____________ forms the first link in transmitting the gas forces to the output shaft.

a) Cylinder

b) Piston

c) Combustion chamber

d) Exhaust manifold

Answer: b

Explanation: Piston fits perfectly into the cylinder providing a gas-tight space with the piston rings and the lubricant and forms the first link in transmitting the gas forces to the output shaft.

4. What is the function of a fuel pump in a petrol pump?

a) inject fuel in cylinder

b) supply fuel when carburetor fails

c) pump fuel so that it reaches carburettor

d) improve thermal efficiency

Answer: c

Explanation: None.

5. If overhead clearance is less, then which of the following type of engine should be selected?

a) V-type

b) In-line type

c) Vertical

d) Horizontal

Answer: d

Explanation: None.

6. Which is the false statement about the advantages of V-type engine?

a) compact design requiring lesser space

b) improved distribution of air to cylinder

c) casting less liable to distortion

d) less overhead clearance

Answer: d

Explanation: In horizontal type engine, less overhead clearance is found.

7. The pistons are usually given a coating such as tin plating in order to __________

a) reduce weight

b) conduct heat efficiently

c) reduce the possibility of scoring

d) reduce friction

Answer: c

Explanation: Pistons are provided with tin coating to reduce scoring.

8. Piston rings are usually made of __________

a) cast iron

b) aluminium

c) carbon steel

d) phosphor bronze

Answer: a

Explanation: None.

9. Piston rings are plated with chromium, cadmium or phosphate in order to __________

a) reduce cost

b) improve surface finish

c) prevent clogging

d) reduce wear and eliminate scuffing

Answer: d

Explanation: Piston rings are plated to reduce wear and eliminate scuffing.

10. The top piston ring nearer to the piston crown is known as __________

a) compression ring

b) oil ring

c) scrapper ring

d) groove ring

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Scavenging Process”.

1. The process of clearing the cylinder after the expansion stroke is called scavenging process.

a) True

b) False

Answer: a

Explanation: Scavenging process is defined as the process of clearing the cylinder after the expansion stroke.

2. Scavenging process is the replacement of combustion products in the cylinder from the previous power stroke with fresh air charge to be burned in the next cycle.

a) True

b) False

Answer: a

Explanation: None.

3. The efficiency of a two stroke engine does not depend on the effectiveness of the scavenging process.

a) True

b) False

Answer: b

Explanation: Actually, the efficiency of a two stroke engine greatly depends on the effectiveness of the scavenging process.

4. Inadequate scavenging leads to high mean indicated pressure which results in high weight and high cost per kW for the engine.

a) True

b) False

Answer: b

Explanation: In fact, inadequate scavenging leads to low mean indicated pressure which results in high weight and high cost per kW for the engine.

5. Inadequate scavenging leads to a low amount of oxygen availability which results in incomplete combustion leading to higher specific fuel combustion.

a) True

b) False

Answer: a

Explanation: None.

6. Inadequate scavenging leads to contamination of lubricating oil to a greater extent which reduces the lubricating qualities and eventually results in increased wear of piston and cylinder liners.

a) True

b) False

Answer: a

Explanation: None.

7. Scavenging angle is the crank angle during which both inlet and exhaust port are open.

a) True

b) False

Answer: a

Explanation: None.

8. Scavenging period is the time period taken for crank angle.

a) True

b) False

Answer: b

Explanation: In fact, scavenging period is the time period taken for scavenging angle.

9. Which of the following are the theoretical scavenging processes?

a) perfect scavenging

b) perfect mixing

c) short circuiting

d) all of the mentioned

Answer: d

Explanation: The theoretical scavenging processes are

i) perfect scavenging

ii) perfect mixing

iii) short circuiting.

10. In short circuiting process, the fresh charge coming from the scavenge manifold directly goes out of the exhaust ports without removing combustion products.

a) True

b) False

Answer: a

Explanation: None.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Two-Stroke Engine”.

1. In a two stroke engine, the working cycle is completed in two revolutions of the crankshaft.

a) True

b) False

Answer: b

Explanation: In a two stroke engine, the working cycle is completed in one revolution of the crankshaft.

2. A two stroke cycle engine gives _____________ the number of power strokes as compared to the four stroke cycle engine, at the same engine speed.

a) half

b) same

c) double

d) four times

Answer: c

Explanation: None.

3. A two stroke cycle engine occupies larger floor area than a four stroke cycle engine.

a) True

b) False

Answer: b

Explanation: A two stroke cycle engine occupies less floor area than a four stroke cycle engine.

4. A two stroke engine gives _____________ mechanical efficiency than a four stroke cycle engine.

a) higher

b) lower

c) equal

d) none of the mentioned

Answer: a

Explanation: As compared to a four stroke cycle engine, the mechanical efficiency of two stroke engine gives higher.

5. The two stroke cycle engine have lighter flywheel.

a) True

b) False

Answer: a

Explanation: None.

6. Thermal efficiency of a two stroke cycle engine is _____________ a four stroke cycle engine.

a) equal to

b) less than

c) greater than

d) none of the mentioned

Answer: b

Explanation: None.

7. In a petrol engine, the mixture has the lowest pressure at the __________

a) beginning of suction stroke

b) end of suction stroke

c) end of compression stroke

d) none of the mentioned

Answer: b

Explanation: In a petrol engine, only at the end of the suction stroke, the mixture has the lowest pressure.

8. In compression ignition engines, swirl denotes a __________

a) haphazard motion of the gases in the chamber

b) rotary motion of the gases in the chamber

c) radial motion of the gases in the chamber

d) none of the mentioned

Answer: b

Explanation: In compression ignition engines, swirl denotes a rotary motion of the gases in the chamber as swirl is always related to rotary motion.

9. The injector nozzle of a compression ignition engine is required to inject fuel at sufficiently high pressure in order to __________

a) inject fuel in a chamber of high pressure at the end of the compression stroke

b) inject fuel at a high velocity to facilitate atomization

c) ensure that penetration is not high

d) all of the mentioned

Answer: d

Explanation: The injector nozzle of a compression ignition engine is required to inject fuel at a sufficiently high pressure in order to

i) inject fuel in a chamber of high pressure at the end of compression stroke.

ii) inject fuel at a high velocity to facilitate atomization.

iii) ensure that penetration is not high.

10. Which of the following engines will have a heavier flywheel than the remaining ones?

a) 30 kW four stroke petrol engine running at 1500 r.p.m

b) 30 kW two stroke petrol engine running at 1500 r.p.m

c) 30 kW two stroke diesel engine running at 750 r.p.m

d) 30 kW four stroke diesel engine running at 750 r.p.m

Answer: a

Explanation: The flywheel in a four stroke petrol engine is heavier than in a two stroke petrol engine and there is no flywheel in a diesel engine.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Scavenging Pumps”.

1. Piston type pump is used for low speed and single or two cylinder engines.

a) True

b) False

Answer: a

Explanation: None.

2. Centrifugal blower is used for small and medium engines.

a) True

b) False

Answer: b

Explanation: In fact, roots blower is used for small and medium engines.

3. Centrifugal blower is employed for large and high output engines.

a) True

b) False

Answer: a

Explanation: None.

4. Scavenging systems, based on charge flow are classifies as __________

a) uniflow

b) loop or reverse scavenging

c) cross scavenging

d) all of the mentioned

Answer: d

Explanation: Scavenging systems, based on charge flow are classifies as

i) uniflow

ii) loop or reverse scavenging

iii) cross scavenging.

5. Pressure loss co-efficient is defined as the ratio between the main upstream and downstream pressures during the scavenging period.

a) True

b) False

Answer: a

Explanation: None.

6. __________ scavenging system has the highest efficiency.

a) Loop or reverse

b) Uniflow

c) Cross

d) None of the mentioned

Answer: b

Explanation: Of all the above only uniflow scavenging system has the highest efficiency.

7. In __________ scavenging, the fresh air first sweeps across the piston top, moves up and then down finally out through the exhaust.

a) loop

b) uniflow

c) cross

d) none of the mentioned

Answer: a

Explanation: None.

8. In __________ scavenging system the inlet and exhaust ports are located on opposite sides of the cylinder.

a) loop

b) uniflow

c) cross

d) none of the mentioned

Answer: c

Explanation: None.

9. Crankcase scavenging arrangement is very economical and inefficient in operation.

a) True

b) False

Answer: b

Explanation: Actually, crankcase scavenging arrangement is very uneconomical and inefficient in operation.

10. Scavenging process consists of __________

a) pre-blowdown stages

b) blowdown

c) scavenging

d) all of the mentioned

Answer: d

Explanation: Scavenging process consists of

i) pre-blowdown stages

ii) blowdown stages

iii) scavenging

iv) additional charging.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Advantages of Two Stroke Engines”.

1. The work required to overcome the friction of the exhaust and suction strokes is saved.

a) True

b) False

Answer: a

Explanation: None.

2. As there is a working stroke in every revolution, a more uniform turning moment is obtained on the crankshaft and therefore, a __________ flywheel is required.

a) heavier

b) slower

c) lighter

d) none of the mentioned

Answer: c

Explanation: None.

3. Two stroke engines are __________ than four stroke engines for the same power output and speed.

a) heavier

b) slower

c) lighter

d) none of the mentioned

Answer: c

Explanation: None.

4. For the same output, two stroke engines occupy ___________ space.

a) greater

b) lesser

c) same

d) none of the mentioned

Answer: b

Explanation: None.

5. The construction of a two stroke cycle engine is ____________ because it has ports instead of valves.

a) complex

b) simple

c) unpredictable

d) none of the mentioned

Answer: b

Explanation: None.

6. In case of two stroke engines because of scavenging, burnt gases remain in the clearance space as in case of four stroke engines.

a) True

b) False

Answer: b

Explanation: No, in fact in two stroke engines because of scavenging, burnt gases do not remain in the clearance space as in case of four stroke engines.

7. In a four stroke cycle diesel engine, compression __________

a) starts at 40º after bottom dead center and ends at 10º before top dead center

b) starts at 40º before top dead center and ends at 40º after bottom dead center

c) starts at top dead center and ends at 40º before bottom dead center

d) may start and end anywhere

Answer: a

Explanation: None.

8. In a four stroke cycle diesel engine, the exhaust valve __________

a) opens at 30º before bottom dead center and closes at 10º after top dead center

b) opens at bottom dead center and closes at top dead center

c) opens at 30º after bottom dead center and closes at 10º before top dead center

d) may open or close anywhere

Answer: a

Explanation: None.

This set of IC Engine Question Bank focuses on “Disadvantages of Two Stroke Engines”.

1. High speed two stroke engines are ____________ efficient owing to the reduced volumetric efficiency.

a) high

b) less

c) equal

d) none of the mentioned

Answer: b

Explanation: None.

2. With engines working on Otto cycle, a part of the mixture is lost as it escapes through the exhaust port during scavenging.

a) True

b) False

Answer: a

Explanation: None.

3. In Otto cycle, with increase in fuel consumption, thermal efficiency is __________

a) increased

b) reduced

c) remains same

d) none of the mentioned

Answer: b

Explanation: None.

4. Part of the piston stroke is lost with the provision of the ports thus the effective compression is less in case of two stroke engines.

a) True

b) False

Answer: a

Explanation: None.

5. Two stroke engines are liable to cause a ____________ consumption of lubricating oil.

a) lighter

b) heavier

c) unpredictable

d) none of the mentioned

Answer: b

Explanation: Two stroke engines are liable to cause a heavier consumption of lubricating oil while in four stroke the consumption is less.

6. With heavy loads, two stroke engines get heated due to excessive heat produced.

a) True

b) False

Answer: a

Explanation: None.

7. At light loads, the running of the engine is not very smooth because of the __________ dilution of charge.

a) decreased

b) increased

c) equal

d) none of the mentioned

Answer: b

Explanation: None.

8. Which of the following engines will have heavier flywheel than the remaining ones?

a) 30 kW four stroke petrol engine running at 1500 r.p.m

b) 30 kW two stroke petrol engine running at 1500 r.p.m

c) 30 kW two stroke diesel engine running at 750 r.p.m

d) 30 kW four stroke diesel engine running at 750 r.p.m

Answer: a

Explanation: The flywheel in a four stroke petrol engine is heavier than in a two stroke petrol engine and there is no flywheel in a diesel engine.

This set of IC Engines Multiple Choice Questions & Answers  focuses on “Comparison of Two Stroke S.I. and C.I. Engines – 1”.

1. Which of the following option is correct when diesel is compared to petrol?

a) highly ignitable

b) more difficult to ignite

c) less difficult to ignite

d) none of the mentioned

Answer: b

Explanation: None.

2. If the temperature of intake air in internal combustion engine increases, then its efficiency will __________

a) remain same

b) decrease

c) increase

d) none of the mentioned

Answer: b

Explanation: None.

3. If petrol is used in a diesel engine, then __________

a) low power will be produced

b) efficiency will be low

c) higher knocking will occur

d) black smoke will be produced

Answer: c

Explanation: Petrol is not used in diesel engine because if petrol is used in a diesel engine, then higher knocking will occur.

4. A petrol engine, during suction stroke draws __________

a) air only

b) petrol only

c) a mixture of petrol and air

d) none of the mentioned

Answer: c

Explanation: None.

5. In order to mix air and petrol in the required proportion and to supply it to the engine during suction stroke, then ____________ is employed.

a) fuel pump

b) injector

c) carburetor

d) none of the mentioned

Answer: c

Explanation: Carburetor is employed in order to mix air and petrol in the required proportion and to supply it to the engine during suction stroke.

6. A diesel engine, during suction stroke draws __________

a) air only

b) diesel only

c) a mixture of petrol and air

d) none of the mentioned

Answer: a

Explanation: In a diesel engine, during suction stroke only air is drawn.

7. The colour of exhaust from diesel engine is generally __________

a) white

b) bluish

c) black

d) violet

Answer: c

Explanation: None.

8. The pressure at the end of compression, in petrol engines, is approximately __________

a) 10 bar

b) 20 bar

c) 25 bar

d) 35 bar

Answer: a

Explanation: None.

9. A petrol engine has compression ratio from __________

a) 6 to 10

b) 10 to 15

c) 15 to 25

d) 25 to 40

Answer: a

Explanation: None.

10. The running cost of a petrol engine is ____________ that of a diesel engine.

a) higher than

b) lower than

c) equal to

d) none of the mentioned

Answer: a

Explanation: None.

This set of IC Engine Questions and Answers for Entrance exams focuses on “Comparison of Two Stroke S.I. and C.I. Engines – 2”.

1. The thermal efficiency of a petrol engine is ____________ as compared to diesel engine.

a) same

b) less

c) more

d) none of the mentioned

Answer: b

Explanation: None.

2. The mean effective pressure of a diesel engine having fixed compression ratio will ____________ if cut off ratio decreases.

a) increase

b) decrease

c) remain same

d) none of the mentioned

Answer: b

Explanation: None.

3. The indicated mean effective pressure of an engine is obtained from the indicator diagram drawn with the help of an engine indicator.

a) True

b) False

Answer: a

Explanation: None.

4. The power actually developed by the engine cylinder of an I.C. engine is known as __________

a) theoretical power

b) actual power

c) indicated power

d) none of the mentioned

Answer: c

Explanation: None.

5. Number of working strokes per min. for a two stroke cycle engine are ____________ the speed of the engine in r.p.m.

a) equal to

b) one-half

c) twice

d) four-times

Answer: a

Explanation: Number of working strokes per min. for a two stroke cycle engine are equal to the speed of the engine in r.p.m while number of working strokes per min. for a four stroke cycle engine are one half the speed of the engine in r.p.m.

6. Number of working strokes per min. for a four stroke cycle engine are ____________ the speed of the engine in r.p.m.

a) equal to

b) one-half

c) twice

d) four-times

Answer: b

Explanation: Number of working strokes per min. for a four stroke cycle engine are one half the speed of the engine in r.p.m. while number of working strokes per min. for a two stroke cycle engine are equal to the speed of the engine in r.p.m.

7. In a petrol engine, the mixture has the lowest pressure at the __________

a) beginning of suction stroke

b) end of suction stroke

c) end of compression stroke

d) none of the mentioned

Answer: b

Explanation: None.

8. In compression ignition engines, swirl denotes a __________

a) haphazard motion of the gases in the chamber

b) rotary motion of the gases in the chamber

c) radial motion of the gases in the chamber

d) none of the mentioned

Answer: b

Explanation: None.

9. The injector nozzle of a compression ignition engine is required to inject fuel at sufficiently high pressure in order to __________

a) inject fuel in a chamber of high pressure at the end of the compression stroke

b) inject fuel at a high velocity to facilitate atomization

c) ensure that penetration is not high

d) all of the mentioned

Answer: d

Explanation: The injector nozzle of a compression ignition engine is required to inject fuel at sufficiently high pressure in order to

i) inject fuel in a chamber of high pressure at the end of the compression stroke.

ii) inject fuel at a high velocity to facilitate atomization.

iii) ensure that penetration is not high.

This set of IC Engine Questions and Answers for Campus interviews focuses on “Advantages of Four Stroke Engines”.

1. In a four stroke engine, the working cycle is completed in __________

a) one revolution of the crankshaft

b) two revolution of the crankshaft

c) three revolution of the crankshaft

d) four revolution of the crankshaft

Answer: b

Explanation: In a four stroke engine, the working cycle is completed in two revolution of the crankshaft while while in a two stroke engine, the working cycle is completed in one revolution.

2. Theoretically, a four stroke engine should develop ____________ power as that of a two stroke cycle engine.

a) half

b) same

c) double

d) four times

Answer: a

Explanation: None.

3. In a four stroke cycle engine, the sequence of operation is __________

a) suction, compression, expansion and exhaust

b) suction, expansion, compression and exhaust

c) expansion, compression, suction and exhaust

d) compression, expansion, suction and exhaust

Answer: a

Explanation: Four stroke cycle engine works on four strokes, i.e- suction, compression, expansion and exhaust.

4. In a four stroke cycle petrol engine, the pressure inside the engine cylinder during the suction stroke is ____________ the atmospheric pressure.

a) equal to

b) below

c) above

d) none of the mentioned

Answer: b

Explanation: None.

5. In a four stroke cycle petrol engine, the inlet valve __________

a) opens at top dead center and closes at bottom dead center

b) opens at 20º before top dead center and closes at 40º after bottom dead center

c) opens at 20º after top dead center and closes at 20º before bottom dead center

d) may open or close anywhere

Answer: b

Explanation: None.

6. In a four stroke cycle petrol engine, the compression __________

a) starts at 40º after bottom dead center and ends at 30º before top dead center

b) starts at 40º before bottom dead center and ends at 30º after top dead center

c) starts at bottom dead center and ends at top dead center

d) may start and end anywhere

Answer: a

Explanation: None.

7. In a four stroke cycle petrol engine, the charge is ignited at __________

a) 30º before top dead center

b) 30º after top dead center

c) 30º before bottom dead center

d) 30º after bottom dead center

Answer: a

Explanation: None.

8. In a four stroke cycle petrol engine, the expansion __________

a) starts at top dead center and ends at bottom dead center

b) starts at 30º before top dead center and ends at 50º before bottom dead center

c) starts at 30º after top dead center and ends at 50º after bottom dead center

d) may start and end anywhere

Answer: b

Explanation: In a four stroke cycle petrol engine, the expansion starts at 30º before top dead center and ends at 50º before bottom dead center while the compression starts at 40º after bottom dead center and ends at 30º before top dead center.

9. The exhaust valve in a four stroke cycle petrol engine __________

a) opens at 50º before bottom dead center and closes at 15º after top dead center

b) opens at bottom dead center and closes at top dead center

c) opens at 50º after bottom dead center and closes at 15º before top dead center

d) may open or close anywhere

Answer: a

Explanation: The exhaust valve in a four stroke cycle petrol engine opens at 50º before bottom dead center and closes at 15º after top dead center while the inlet valve, opens at 20º before top dead center and closes at 40º after bottom dead center.

10. The inlet valve of a four stroke cycle internal combustion engine remains open for __________

a) 130º

b) 180º

c) 230º

d) 270º

Answer: c

Explanation: None.

11. In a four stroke cycle the minimum temperature inside the engine cylinder occurs at the __________

a) beginning of suction stroke

b) end of suction stroke

c) beginning of exhaust stroke

d) end of exhaust stroke

Answer: a

Explanation: None.

12. In a four stroke cycle petrol engine, the charge is compressed when both the valves  are closed.

a) True

b) False

c) Both the valves are open

d) None of the mentioned

Answer: a

Explanation: None.

13. In a four stroke cycle diesel engine, the inlet valve __________

a) opens at 20º before top dead center and closes at 40º after bottom dead center

b) opens at 20º after top dead center and closes at 20º before bottom dead center

c) opens at top dead center and closes at bottom dead center

d) may open or close anywhere

Answer: a

Explanation: None.