Automobile Engineering Pune University MCQs
Automobile Engineering Pune University MCQs
This set of Automobile Engineering Interview Questions and Answers focuses on “Introduction and History”.
1. In which year was the first automobile built?
a) 1759
b) 1769
c) 1785
d) 1790
Answer: b
Explanation: In 1769, the first automobile was built by French engineer Nicholas Cugnot. The engine was powered by steam. He was the first person who converted the reciprocating motion of the steam piston into rotary motion.
2. Onesiphare Pacqueur invented which one of these?
a) Gear box
b) Steering wheel
c) Differential
d) IC Engine
Answer: c
Explanation: Onesiphare Pacqueur of France invented the first differential.
3. Trucks and Buses use which type of fuel?
a) Petrol
b) LPG
c) CNG
d) Diesel
Answer: d
Explanation: Diesel fuel is used in heavy vehicles like trucks and buses.
4. A 4*2 drive vehicle implies that
a) It has 4*2=8 wheels
b) It has 2 auxiliary wheels and 4 drive wheels
c) It has 4 wheels out of which 2 are drive wheels
d) None of the mentioned
Answer: c
Explanation: If mentioned as a*b drive, ‘a’ represents number of wheels and ‘b’ represents number of drive wheels.
5. A conventional suspension system uses which of these?
a) Leaf Springs
b) Coil Springs
c) Torsion bars
d) None of the mentioned
Answer: a
Explanation: Leaf Spring is used in conventional suspension systems. It is also called laminated spring because it has layers of metals in elliptical or in semi-elliptical shapes.
6. Sir Rudolf Diesel invented diesel engine in which year?
a) 1905
b) 1916
c) 1920
d) 1913
Answer: d
Explanation: Diesel engine was invented by Rudolf Diesel in 1913.
7. Hindustan Motors Limited, Calcutta was setup in which year
a) 1950
b) 1945
c) 1943
d) 1942
Answer: c
Explanation: In 1943 and 1944 two automobile companies namely, Hindustan Motors Limited, Calcutta and Premier Automobiles Limited, Bombay were setup in india.
8. Ford started production of his model ‘T’ car with an initial run of how many vehicles
a) 15000
b) 6000
c) 2000
d) 20000
Answer: d
Explanation: Model’T’ cars were the first assembly line produced cars and started with an initial run of 20000 units.
9. In 1832 who patented first 3-speed Transmission
a) W.H.James
b) Rudolf Diesel
c) Richard Trevithick
d) William Ford
Answer: a
Explanation: W.H.James patented the first 3-speed Transmission in England.
10. First car arrived in India in which year
a) 1890
b) 1893
c) 1897
d) 1901
Answer: c
Explanation: In 1897 first car arrived in india.
This set of Automobile Engineering Questions and Answers for Entrance exams focuses on “Automobiles Classification”.
1. Two door and four door type automobiles are classified as _______
a) Sedan
b) Convertible
c) Special purpose vehicles
d) Pick ups
Answer: a
Explanation: 2 door and 4 door type vehicles are classified as Sedan.
2. Which of these falls under LMV category based on capacity?
a) Motorbikes
b) Cars
c) Buses
d) Trains
Answer: b
Explanation: Cars and jeeps are Light Motor Vehicles based on their capacity.
3. Most of the ______________ vehicles have automatic transmission.
a) Indian
b) Japanese
c) American
d) British
Answer: c
Explanation: Most american vehicles are of automatic transmission type.
4. A delivery van falls under the category of which type of vehicles.
a) Heavy passenger vehicles
b) Light passenger vehicles
c) Heavy goods vehicles
d) Light goods vehicles
Answer: d
Explanation: A delivery van is a light goods vehicle.
5. Load per axle for a vehicle can be reduced by which of the following methods.
a) By increasing distance between the axles
b) By increasing the number of tyres
c) By increasing the number of axles
d) By decreasing the length of an axle
Answer: c
Explanation: Load per axle can be reduced by increasing the number of axles.
6. Abbreviation HEVs stands for what
a) Highly Efficient Vehicles
b) Hybrid Electric Vehicles
c) Highly Economic Vehicles
d) Highly Engineered Vehicles
Answer: b
Explanation: Hybrid Electric Vehicles are also known as HEVs.
7. In Automobile, what does SUV stand for?
a) Sport Utility Vehicle
b) Sub-urban Utility Vehicles
c) Short Urban Vehicles
d) Super Utility Vehicles
Answer: a
Explanation: SUV stands for Sport Utility Vehicle. SUVs are generally large vehicles with higher ground clearance. These types of vehicles have more power and are designed for both rough surfaces and city roads.
8. Why is the term ‘Cabriolet’ used for a car?
a) Because of non-foldable roof
b) Because of foldable roof
c) Because it is a coupe
d) Because it has Higher ground clearance
Answer: b
Explanation: A cabriolet means ‘a car with a foldable roof.’ So a cabriolet may have any
number of seats and it may have higher ground clearance but it should have a foldable roof. Coupe cars have a fixed roof and two doors.
9. BMW is a leading German engine and automobile manufacturing company. Here BMW is an abbreviation for
a) British Motor Works
b) Bayerische Motoren Werke
c) Bayerische Machine Werke
d) Bright Motor Works
Answer: b
Explanation: The full form of BMW is Bayerische Motoren Werke.
10. Which one of these is a Sports car?
a) BMW X6
b) Mercedes-Benz S-Class
c) Audi A6
d) Porsche 911
Answers: d
Explanation: Porsche 911 is a two doored sports car which is rear engined. In Porsche
911, the engine is placed on the rear of the vehicle. It has independent suspension which makes this car very comfortable.
This set of Automobile Engineering Questions and Answers for Freshers focuses on “Parts of an Automobile”.
1. The transmission system transmits _________ from engine to wheels.
a) Speed
b) Power
c) Current
d) Pressure
Answer: b
Explanation: Power from engine to wheels cannot be directly transmitted. So the transmission system transmits the power from engine to wheels in a very controlled manner. Generally, the transmission system consists of gears which provides different types of gear ratios.
2. Which of the following is not a part of the transmission system?
a) Clutch
b) Axles
c) Wheels
d) Gear box
Answer: c
Explanation: Transmission system is used to transmit the power from engine to wheels. Transmission system consists of gears, and clutches to transmit the power at different gear ratios. Wheels are considered as a part of the automobile chassis.
3. The loads supported by an automobile frame are _____
a) Weight of the body, passengers and cargo loads
b) Torque from engine and transmission
c) Sudden impacts from collisions
d) All of the mentioned
Answer: d
Explanation: Frame of an automobile supports the weight of the body, passengers and cargo loads. There are different types of frames which are used to support the weight of the automobile parts.
4. An automobile chassis does not include which one of the following parts?
a) Shock absorbers
b) Steering system
c) Differential
d) Brakes
Answer: c
Explanation: A ‘differential’ is a component of the transmission system. Differential provides different speed to both of the wheels. Due to this, the skidding of the wheels are prevented.
5. The electrical system of an automobile contains which of the following?
a) Battery
b) Alternators
c) Lighting systems
d) All of the mentioned
Answer: d
Explanation: Battery, alternators and lighting systems are the major electrical components of an automobile.
6. Which of these were or are used in automobiles to provide suspension?
a) Leaf springs
b) Coil springs
c) Torsion bars
d) All of the mentioned
Answer: d
Explanation: All the three mentioned are types of suspension systems.
7. What are ‘Air Dams’?
a) Spoilers at the front of a vehicle
b) Spoilers at the rear of a vehicle
c) Spoilers at the sides of a vehicle
d) Spoilers at the top of a vehicle
Answer: a
Explanation: Spoilers at the front of a vehicle are known as Air Dams. Air dams are used to increase the downforce of the vehicle. These dams oppose the force which tries to uplift the vehicle.
8. What are ‘Wings’ of a vehicle?
a) Spoilers at the front of a vehicle
b) Spoilers at the rear of a vehicle
c) Spoilers at the sides of a vehicle
d) Spoilers at the top of a vehicle
Answer: b
Explanation: Spoilers located at the rear of a vehicle are known as Wings. These wings are used to generate downforce at the vehicle. This force acts downward on the vehicle which keeps the vehicle on the track.
9. The lid that covers the engine top in a car and situated at the front is called ________
a) Gill
b) Softtop
c) Bonnet
d) Spoiler
Answer: c
Explanation: The hinged lid covering the engine is called ‘Bonnet’ or ‘hood’.
10. An upraised part on the hood which directs the air flow into the engine compartment is called _____
a) Spoiler
b) Hotpipe
c) Hood scoop
d) Wings
Answer: c
Explanation: Hood scoop makes a channel of air to flow into the engine compartment.
11. Why ‘Bumpers’ are used in cars?
a) To reduce the impact in case of low speed collisions
b) To improve the aerodynamics of a car
c) To increase the engine performance
d) None of the mentioned
Answer: a
Explanation: Bumpers reduce the impact of collision and save the passengers from getting injured.
12. The central portion of the wheel is called _______
a) Rim
b) Scale
c) Hub
d) Axle
Answer: c
Explanation: The central portion of the wheel is called ‘hub’.
13. A _____ is a horizontal surface at the back of a car and serves as a lid to the trunk.
a) Trunktop
b) Deck
c) Hood
d) Backlight
Answer: b
Explanation: The component that serves as a lid on the trunk is called ‘Deck’.
14. A ‘bucket seat’ can accomodate how many persons?
a) One
b) Two
c) Four
d) None of the mentioned
Answer: a
Explanation: A bucket seat can accomodate only a single passenger.
15. ‘Head restraints’ are an _________
a) Automotive style feature
b) Automotive safety feature
c) Automotive performance feature
d) None of the mentioned
Answer: b
Explanation: Head restraints are safety features that protect the vertibral column of the passengers during collisions.
This set of Automobile Engineering online test focuses on “Description of Automobiles”.
1. Which of these is not necessary for the description of an automobile?
a) Type
b) Capacity
c) Colour
d) Model
Answer: c
Explanation: Colour is not a necessary factor to describe an automobile because colour does not impact on the performance of an automobile. The performance of an automobile depends upon the type, capacity and Model of that automobile.
2. Which of these is necessary for the description of an automobile?
a) Make
b) Model
c) Capacity
d) All of the mentioned
Answer: d
Explanation: Make, model, capacity are all essential informations for describing an automobile.
3. ‘Volkswagen Polo’ is a _______
a) Ultra-compact car
b) Sub-compact car
c) Compact car
d) Executive car
Answer: b
Explanation: Volkswagen Polo is a sub-compact car.
4. ‘Maruti 800’ is a _________
a) Sub-compact car
b) Compact car
c) City car
d) Sports car
Answer: c
Explanation: ‘Maruti 800’ is a sub-urban city car.
5. Which of these cars is a Crossover SUV?
a) Nissan Pathfinder
b) Hyundai Sonata
c) Suzuki Servo
d) Fiat Panda
Answer: a
Explanation: Nissan Pathfinder is a Crossover SUV car.
6. What was the initial pricetag of ‘Tata Nano’ a city car by Tata Motors?
a) Rs.1,50,000
b) Rs.1,00,000
c) Rs.2,50,000
d) Rs.2,00,000
Answer: b
Explanation: Tata Nano came into market with an initial pricetag of 1,00,000 indian rupees.
7. Which of these is a compact executive car?
a) Mercedes-Benz S Class
b) Audi A8
c) Audi A4
d) Mercedes-Benz E Class
Answer: c
Explanation: Audi A4 is a compact executive car.
8. Which of these is a ‘Convertible’?
a) Mahindra Scorpio
b) Volkswagen Golf GTI
c) Cadillac XTS
d) Honda S2000
Answer: d
Explanation: Honda S2000 is considered as a Convertible car.
9. A Roadster is a convertible with how many seats?
a) One
b) Two
c) Four
d) Six
Answer: b
Explanation: A Roadster is a two seater convertible car.
10. Mercedes-Benz E Class is ______
a) A compact minivan
b) An estate car
c) An executive car
d) A compact executive car
Answer: c
Explanation: Mercedes-Benz E Class is considered an executive mid-luxury car.
11. Ford Falcon is an example of _________
a) Australian muscle car
b) American muscle car
c) Luxury vehicle
d) None of the mentioned
Answer: a
Explanation: Ford Falcon is an australian muscle car.
This set of Automobile Engineering Interview Questions and Answers for freshers focuses on “Performance of an Automobile”.
1. What is the power delivered by the engine to the crankshaft called?
a) Shaft power
b) Horse power
c) Brake power
d) None of the mentioned
Answer: c
Explanation: The total power delivered by the engine to the crankshaft is called Brake power. It can also be defined as the difference between indicated power and friction power.
2. If ‘T’ is torque and ‘N’ is speed then the required expression for Brake power ‘B.P’ in kWs is _________
a) 2πNT/6000
b) 2πNT/60000
c) πNT/6000
d) πNT/60000
Answer: b
Explanation: The required expression is B.P = 2πNT/60000.
3. The torque available at the contact between road and driving wheel is called _________
a) Brake power
b) Friction power
c) Tractive effort
d) Engine torque
Answer: c
Explanation: The torque between road and wheel is called tractive effort. Tractive effort is used to describe the pulling capability of an automobile. The tractive force is inversely proportional to the velocity of the vehicle.
4. If ‘V’ is vehicle speed and ‘R’ is radius of driving wheel then the rpm of the driving wheel is given by _______
a) rpm = V/2πR
b) rpm = 2πV/R
c) rpm = πR/V
d) rpm = πV/R
Answer: a
Explanation: The rpm of the driving wheel can be expressed as rpm = V/2πR.
5. Which of these is not a power loss which takes place between engine and driving wheel?
a) Power loss due to friction of piston bearings and gears
b) Power loss from clutch to drive wheel due to friction of various parts
c) Transmission line loss
d) None of the mentioned
Answer: d
Explanation: All the above mentioned losses are encountered while transmission of power. About one third of the power of the fuel is wasted due to the friction between different parts of an automobile. This loss can be reduced by using different engine oils.
6. The force that opposes the motion of a vehicle is _______
a) Rolling resistance
b) Gradient resistance
c) Wind or air resistance
d) All of the mentioned
Answer: d
Explanation: Rolling resistance, gradient resistance and air resistance all oppose the motion of a vehicle.
7. Rolling resistance doesnot depend on which of the following factors?
a) Load on each road wheel
b) Radius of driving wheel
c) Wheel inflation pressure
d) Nature of road surface
Answer: b
Explanation: Rolling resistance does not depend on radius of driving wheel.
8. For an average type of road surface what percentage of vehicle’s weight constitutes rolling resistance?
a) 5 to 10%
b) 1 to 2%
c) 2 to 5%
d) 0 to 3%
Answer: b
Explanation: On an average road surface rolling resistance is 1 to 2% of vehicle’s weight.
9. Wind or air resistance depends on which of the following factors?
a) Shape and size of vehicle body
b) Air velocity
c) Speed of vehicle
d) All of the mentioned
Answer: d
Explanation: Air resistance on a vehicle depends on all the above mentioned factors.
10. If ‘k’ is coefficient of air resistance, ‘A’ is frontal area projected by the vehicle in square metres and ‘V’ is vehicle speed then the expession for air resistance ‘A.R’ on the vehicle is _________
a) A.R = k*A*V^2
b) A.R = k*A*V^3
c) A.R = 2k*A*V
d) A.R = k*A*V
Answer: a
Explanation: The correct expression for air resistance is A.R = k*A*V 2 .
11. The value of coefficient of air resistance for average cars is approximately equal to __________
a) 0.32
b) 0.032
c) 0.0032
d) 1.32
Answer: c
Explanation: For average cars, value of coefficient of air resistance is approx 0.0032.
12. One Horse Power is approximately equal to _____ Watts.
a) 810
b) 545
c) 634
d) 746
Answer: d
Explanation: 1 H.P = 746 Watts.
13. Gradient resistance for a vehicle depends on which of the following factors?
a) Weight of the vehicle
b) Size of the vehicle
c) Width of tyres
d) Speed of the vehicle
Answer: a
Explanation: Gradient resistance depends on weight of the vehicle.
14. Power to weight ratio for high performance cars can range up to _______
a) 150
b) 190
c) 230
d) 280
Answer: c
Explanation: The ratio of power to weight of high performance cars can range as high as 230.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Heat Engines”.
1. A heat engine converts heat energy from fuel combustion or any other source into which type of work?
a) Electrical work
b) Mechanical work
c) Pressure work
d) None of the mentioned
Answer: b
Explanation: A heat engine gives mechanical work as output. In a heat engine, input is given in the form of heat and this heat is converted into mechanical work. The remaining heat which is not converted into work is exhausted.
2. A steam engine comes under the category of ________
a) External combustion engines
b) Internal combustion engines
c) All of the mentioned
d) None of the mentioned
Answer: a
Explanation: A steam engine is an External combustion engine. Steam engine is a type of heat engine in which heat is used as an input and this heat is converted into mechanical work. Steam pushes the piston and reciprocating motion of the piston is converted into rotary motion.
3. Which of these is a power absorbing heat engine?
a) Steam engine
b) Petrol engine
c) Air compressor
d) None of the mentioned
Answer: c
Explanation: An air compressor is a power absorbing heat engine.
4. Which of these is a type of reciprocating steam engine?
a) Simple
b) Compound
c) Uniflow
d) All of the mentioned
Answer: d
Explanation: Simple, compound and uniflow are types of reciprocating steam engine.
5. A gas undergoes step 2 in Carnot cycle. Which of these processes describes the 2nd step?
a) Isentropic expansion
b) Isentropic compression
c) Isothermal expansion
d) Isothermal compression
Answer: a
Explanation: The 2nd process in carnot cycle is isentropic expansion.
6. A gas undergoes step 4 in Carnot cycle. Which of these processes describes the 2nd step?
a) Isentropic expansion
b) Isentropic compression
c) Isothermal expansion
d) Isothermal compression
Answer: b
Explanation: The 4th process in carnot cycle is isentropic compression.
7. A gas undergoes isothermal compression in Carnot cycle. Which step does it undergo?
a) 1st
b) 2nd
c) 3rd
d) 4th
Answer: c
Explanation: Isothermal compression is the 3rd step in Carnot cycle.
8. Thermal power plants operate on which of these cycles?
a) Otto cycle
b) Rankine cycle
c) Carnot cycle
d) Stirling cycle
Answer: b
Explanation: Thermal power plants operate on Rankine cycle.
9. The efficiency of a combined cycle gas turbine can range as high as ________
a) 20%
b) 30%
c) 40%
d) 60%
Answer: d
Explanation: A steam cooled combined cycle gas turbine can have efficiency as high as 60%.
10. One ‘ton of refrigeration’ equals how much Btu/hr.
a) 14,500 Btu/hr
b) 12,000 Btu/hr
c) 13,000 Btu/hr
d) 15,000 Btu/hr
Answer: b
Explanation: One “ton of refrigeration ” is equivalent to 12,000 Btu/hr or 3.5 kW. It is the unit of power which is used to describe the heat extraction capacity of a refrigeration or air conditioning equipment.
This set of Automobile Engineering Questions and Answers for Experienced people focuses on “Development of IC Engines”.
1. In a Otto cycle engine, combustion occurs at __________
a) Constant pressure
b) Constant temperature
c) Constant volume
d) Constant heat
Answer: c
Explanation: Combustion process in an Otto cycle engine occurs at constant volume. Otto cycle has two isentropic processes and two constant volume processes. This cycle is mostly used for petrol engines.
2. In a Diesel cycle engine, combustion occurs at _________
a) Constant pressure
b) Constant temperature
c) Constant volume
d) Constant heat
Answer: a
Explanation: Combustion in a Diesel cycle engine occurs at constant pressure.
3. Heat rejection in diesel cycle is at _________
a) Constant pressure
b) Constant volume
c) Constant temperature
d) None of the mentioned
Answer: b
Explanation: Heat rejection in diesel cycle occurs at constant volume.
4. In a four stroke ic engine, how many strokes are covered for one complete crankshaft revolution?
a) 4
b) 2
c) 1
d) 0.5
Answer: b
Explanation: For a 4 stroke engine, piston covers 2 strokes for one complete crankshaft revolution. It takes two rotations of the crankshaft and 4 strokes of piston to complete one cycle.
5. In a 4-stroke ic engine, which of the strokes is considered as working or power stroke?
a) Suction stroke
b) Compression stroke
c) Expansion stroke
d) Exhaust stroke
Answer: c
Explanation: There are 4 strokes in a 4-stroke ic engine. These are Suction,compression,expansion and exhaust stroke. Out of these, the expansion stroke is called working or power stroke.
6. The valves of an ic engine are made to open and close slowly to _________
a) Increase the engine efficiency
b) Decrease the fuel consumption
c) Allow engine to cool in the meantime
d) Provide silent operation under high speed conditions
Answer: d
Explanation: The valves are made to open and close slowly to provide silent operation under high speed conditions.
7. Which of these is not an assumption made in deriving the formula for air standard of Otto cycle?
a) There is no heat loss during the cycle
b) The compression and expansion are isothermal
c) The heating and cooling strictly take place at constant volume
d) The suction and exhaust take place at atmospheric pressure
Answer: b
Explanation: Compression and expansion are assumed strictly adiabatic in a Otto cycle.
8. Higher efficiency in Otto cycle can be achieved by _______
a) Increasing the compression ratio
b) Decreasing the compression ratio
c) Keeping the compression ratio constant
d) Efficiency does not depend on compression ratio
Answer: a
Explanation: Higher efficiency can be achieved by increasing the compression ratio.
9. The expansion process in diesel engine is ________
a) Isothermal
b) Adiabatic
c) Isobaric
d) None of the mentioned
Answer: b
Explanation: Adiabatic expansion occurs in diesel cycle.
10. In two-stroke cycle engines, what replaces valves of a four-stroke engine?
a) Fins
b) Notches
c) Ports
d) Tubes
Answer: c
Explanation: Valves are replaced by ports in two-stroke engines. Two-stroke engine takes two strokes of piston to complete one revolution of the crankshaft. It also completes the cycle in two strokes.
This set of Automobile Engineering Interview Questions and Answers for Experienced people focuses on “Applications of IC Engines”.
1. A 150 c.c. two-stroke petrol engine running at 5000 rpm can develop a maximum brake power of _________
a) 15 kW
b) 10 kW
c) 5 kW
d) 1 kW
Answer: c
Explanation: These type of engines can develop a maximum brake power of 5 kW.
2. In Wankel engines, how many power strokes occur per rotor revolution?
a) 1
b) 2
c) 3
d) 4
Answer: c
Explanation: Wankel is a type of IC engine which has an eccentric rotor design. For one rotor revolution, there are three power strokes in a Wankel engine. This engine converts pressure into rotating motion.
3. Diesel engine is not employed in which of the following?
a) Pumping sets
b) Air compressors
c) Tractors
d) Motorcycles
Answer: d
Explanation: Diesel engines are not used in motorcycles.
4. Which of the following is not an arrangement of ic engine cylinders?
a) Radial
b) Circular
c) V type engine
d) Opposed cylinder engine
Answer: b
Explanation: Circular arrangement is not used for ic engine cylinders.
5. Which of these is a cylinder head type of an ic engine?
a) X head
b) U head
c) F head
d) C head
Answer: c
Explanation: F type head is a type of an ic engine cylinder head. It can be described as a combination of I-type and L-type head. F-type cylinder heads have an intake manifold and its valves on top of the cylinder.
6. Which of these is not a cylinder head type of an ic engine?
a) L head
b) I head
c) T head
d) X head
Answer: d
Explanation: X head type engines are not in use. The mail cylinder heads used are L-type, I-type, T-type, F-type.
7. What is the disadvantage of using diesel engine in comparison to petrol engine?
a) Higher weight-to-power ratio
b) Higher maintenance cost
c) Greater starting difficulties
d) All of the mentioned
Answer: d
Explanation: All the given are the disadvantages of using a diesel engine over petrol engine.
8. Engines used in tractors are ______
a) Single cylinder engines
b) Two cylinder engines
c) Four cylinder engines
d) Six cylinder engines
Answer: b
Explanation: Two cylinder engine is used in tractors.
9. Engines used in Ashok Leyland Comet trucks are ________
a) Single cylinder engines
b) Two cylinder engines
c) Four cylinder engines
d) Six cylinder engines
Answer: d
Explanation: Ashok Leyland Comet trucks use six cylinder engines.
10. W-type arrangement in twelve and sixteen cylinder engines has ______
a) One row of cylinders
b) Two rows of cylinders
c) Three rows of cylinders
d) Four rows of cylinders
Answer: c
Explanation: W type arrangement has three rows of cylinders.
11. The angle between two cylinders in a two cylinder V-type engine is usually
a) 15 degrees
b) 45 degrees
c) 60 degrees
d) 90 degrees
Answer: c
Explanation: V-type engines have two cylinder banks which make 60 degree angle to each other. It has a number of piston same as the number of cylinders in each bank and they are connected to the same crankshaft.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Engine Cycle”.
1. In an automobile engine the temperature of the piston will be more at __________
a) The crown of the piston
b) The skirt of the piston
c) The piston walls
d) The piston rings
Answer: a
Explanation: The crown of the engine experiences the highest temperature because during the ignition, the crown of the piston compresses the fuel and the ignition takes place just above the crown. So the crown faces the ignition and due to this it faces the highest temperature.
2. The firing order in case of four cylinder inline engines is usually ________
a) 1-2-4-3
b) 1-3-4-2
c) 1-4-3-2
d) Either 1-3-4-2 or 1-4-3-2
Answer: d
Explanation: The firing order of these engines can be either 1-3-4-2 or 1-4-3-2.
3. In case of four cylinder opposed cylinder engines the firing order is ___________
a) 1-4-3-2
b) 1-3-4-2
c) 1-2-3-4
d) 1-2-4-3
Answer: a
Explanation: The firing order in these engines is 1-4-3-2.
4. In case of four cylinder inline engine the number of firing strokes in one revolution of crank is _______
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: In a four cylinder engine the number of firing strokes for one revolution of crank is two.
5. In four cylinder engines the ignition advance depends on _________
a) Quality of fuel
b) Engine speed
c) Cylinder dimensions
d) Quality of fuel and engine speed
Answer: d
Explanation: Ignition advance depends on both quality of fuel and engine speed.
6. Ignition advance is expressed in terms of _________
a) Crank angle
b) Millimetres of piston travel before TDC
c) Time in milli seconds
d) All of the mentioned
Answer: d
Explanation: Ignition advance can be expressed in terms of any of the following.
7. In internal combustion engine the approximate percentage of the combustion heat that passes to the cylinder walls is _________
a) 5%
b) 10%
c) 30%
d) 60%
Answer: c
Explanation: Approximately 30% of heat passes to the cylinder walls.
8. In a four stroke S.I engine the exhaust valve usually opens ______
a) At BDC
b) 35 degree to 60 degree before BDC
c) 35 degree to 60 degree after BDC
d) 10 degree to 20 degree before BDC
Answer: b
Explanation: Exhaust valve opens at 35 degree to 60 degree before BDC.
9. In S.I engine the intake valve closes __________
a) At BDC
b) At TDC
c) 25 degree to 84 degree after BDC
d) 10 degree to 20 degree before TDC
Answer: c
Explanation: The intake valve closes at 25 degree to 84 degree after BDC.
10. In a diesel engine the pressure during combustion may increase to a range at _________
a) 10-15 atm
b) 15-20 atm
c) 20-30 atm
d) 55-75 atm
Answer: d
Explanation: Pressure can increase as high as 55 to 75 atm during combustion in diesel engine.
11. In a diesel engine the temperature of gases under full load may be of the order of __________
a) 550-650 degree Celsius
b) 200-300 degree Celsius
c) 150-200 degree Celsius
d) 100 degree Celsius
Answer: a
Explanation: Temperature under full load may be as high as 550 to 650 degree Celsius.
12. The fuel is injected into the cylinder in diesel engine when the piston is ____________
a) Exactly at TDC after compression stroke
b) Exactly at the BDC before compression stroke
c) Approaching TDC during compression stroke
d) Approaching TDC during exhaust stroke
Answer: c
Explanation: Fuel is injected when piston is approaching TDC during compression stroke.
13. A single cylinder four stroke engine is rotating at 2000 rpm. The number of power strokes occuring in one minute is ________
a) 500
b) 1000
c) 2000
d) 4000
Answer: b
Explanation: For every two revolutions one cylse is completed in a four stroke engine. If speed is 2000 rpm then number of complete cycles per minute is 1000.
14. The pressure in an engine cylinder is less than atmospheric pressure when the engine is performing which stroke?
a) Suction
b) Compression
c) Power
d) Exhaust
Answer: a
Explanation: During suction stroke the inside pressure is less than atmospheric pressure.
15. The angle in degrees moved by the crankshaft of a four cylinder engine between firing impulses is _________
a) 90
b) 180
c) 360
d) 720
Answer: b
Explanation: As engines are alternately fired so the angle moved by crankshaft decreases to 180 between firing impulses.
This set of Automobile Engineering test focuses on “Parts of an IC Engine Cylinder and Liner”.
1. A square type engine is a type of engine which ________
a) Has geometrically square shape
b) Has two vertical and two horizontal cylinders
c) Has cylinder bore length equal to stroke length
d) None of the mentioned
Answer: c
Explanation: A square type engine has cylinder bore length equal to cylinder stroke length.
2. Aluminium cylinder blocks require __________
a) Cast iron Liners
b) Brass Liners
c) Aluminium Liners
d) No Liners
Answer: a
Explanation: Cast iron is the best suited Liner material for aluminium cylinders. Aluminium is used for these types of cylinder blocks because it has higher heat conduction and it is good for engine cooling. It also prevents abnormal combustion.
3. What is the function of an oil scraper ring in an engine?
a) Retain compression
b) Lubricate cylinder walls
c) Maintain vacuum
d) Reduce piston wear
Answer: b
Explanation: Oil scraper rings lubricate cylinder walls. Lubricating oils are most important for an engine because it reduces the friction between walls and other parts and it also works as a cooling agent.
4. When considerable material must be removed to clean up a cylinder bore, the cylinder should be _______
a) Bored
b) Honed
c) Ground
d) Reamed
Answer: a
Explanation: Boring operation can easily remove the required material.
5. The stroke of an engine is the _________
a) Volume of the cylinder
b) Length of the connecting rod
c) Internal diameter of the cylinder
d) Distance between TDC and BDC
Answer: d
Explanation: Distance between TDC and BDc is termed as the stroke of an engine.
6. A four cylinder engine is of capacity 2.4 litres. Then swept volume of one cylinder is ______
a) 400 cubic centimeters
b) 600 cubic centimeters
c) 2400 cubic centimeters
d) 1200 cubic centimeters
Answer: b
Explanation: Volume of one cylinder will be 2.4/4 = 0.6 litres or 600 cubic centimeters.
7. The difference between dry liners and wet liners is __________
a) Cylinder liner touches the coolant jacket in wet liners
b) Wet liners are thicker than dry liners
c) Packing rings are present in wet liners
d) All of the mentioned
Answer: d
Explanation: All the given differences exist between wet and dry liners.
8. The thickness of dry liners ranges from __________
a) 3 mm to 9mm
b) 1.5 mm to 3 mm
c) 1 mm to 2 mm
d) 0.5 mm to 2.5 mm
Answer: b
Explanation: The thickness of dry liners is of about 1.5 mm to 3 mm.
9. The thickness of wet liners ranges from _______
a) 1.5 mm to 6 mm
b) 1 mm to 2 mm
c) 6 mm to 10 mm
d) 0.5 mm to 2.5 mm
Answer: a
Explanation: The thickness of wet liners is of about 1.5 mm to 6 mm.
10. Cylinder liner materials are made of alloy iron containing ____________
a) Manganese
b) Nickel
c) Chromium
d) All of the mentioned
Answer: d
Explanation: Liner is made of alloy iron containing silicon, manganese, nickel and chromium.
This set of Automobile Engineering Quiz focuses on “Various Parts of Engine – 1”.
1. The function of crankcase in two stroke petrol engines is _________
a) It lower downs the temperature
b) It forms a pressurised chamber for fuel air mixture
c) It holds the exhaust gases after combustion
d) None of the mentioned
Answer: b
Explanation: The crankcase of a two stroke engine forms a pressurised air fuel mixture for combustion. It also prevents the atmospheric air or other particles from entering into the chamber.
2. In general, What type of section is used for connecting rods?
a) Forged I-section
b) Forged round section
c) Cast iron square section
d) Forged square section steel
Answer: a
Explanation: Connecting rods are generally of forged I-section type because I-section have higher modulus per unit area in comparison to other sections. I-section is highly resistant to buckling and bending.
3. The purpose of crankcase ventilation is to __________
a) Cool the oil
b) Remove vaporised water and fuel
c) Supply oxygen to the crankcase
d) It assists in maintaining the viscosity of oil
Answer: b
Explanation: Crankcase ventilation removes vaporised water and fuel.
4. The escape of burned gases from the combustion chamber past the pistons and into the crankcase is called _______
a) Gas loss
b) Blow by
c) By pass
d) Passed gas
Answer: b
Explanation: Blow by is the surging of burned gases from combustion chamber into the crankcase.
5. Connecting rod is attached to the piston by the ___________
a) Rod cap
b) Piston pin
c) Cap bolt
d) Lower cap
Answer: b
Explanation: Connecting rod is attached to the piston by piston pin.
6. Engine pistons are generally made of aluminium alloy because ______
a) It is lighter
b) It is stronger
c) It has less wear
d) It absorbs shock
Answer: a
Explanation: Aluminium alloy are used because they are lighter.
7. Piston compression rings are made of _____________
a) Cast iron
b) Steel
c) Aluminium
d) Bronze
Answer: a
Explanation: Cast iron is used for piston compression rings.
8. What type of material is used for Gudgeon pin?
a) Cast iron
b) Aluminium
c) Steel alloy of high strength
d) Hardened and ground steel
Answer: c
Explanation: Gudgeon pins are made of steel alloy of high strength. Gudgeon pins are short hollow pipes. Steel alloy of high strength are used for this pin because it should be very light and also have very high strength and temperature resistance.
9. The purpose of a piston pin is that _________
a) It prevents the valve from rotating
b) It links the connecting rod to the crankshaft
c) It ensure the piston ring to the piston
d) It connect the piston to the connecting rod
Answer: d
Explanation: Piston pin connects the piston to the connecting rod.
10. When no.1 piston of a four cylinder in line four stroke engine is performing the power stroke, no.4 piston is on the stroke called _______
a) Suction
b) Compression
c) Power
d) Exhaust
Answer: a
Explanation: When no.1 piston is on power stroke, no.4 piston will be on suction stroke.
This set of Automobile Engineering MCQs focuses on “Various Parts of Engine – 2”.
1. What is the material of the connecting rod?
a) Mild steel
b) Forged steel
c) Tool steel
d) Cast iron
Answer: b
Explanation: Connecting rod is made of forged steel because the connecting rod should have light weight and high resistance. Connecting rod in the engine should be lightweight because it provides proper balance to the engine and it should have high strength because it goes through cyclic stress.
2. Which of the following item is made of aluminium alloy?
a) Piston ring
b) Piston
c) Connecting rod
d) Crankshaft
Answer: b
Explanation: Aluminium alloy is used in making piston. Aluminium alloys are used for the piston because it provides high resistance to the temperature. Since, the piston faces the highest temperature it must have the highest temperature resistance.
3. Piston pin is also known as ________
a) Gudgeon pin
b) Crank pin
c) Screw pin
d) None of the mentioned
Answer: a
Explanation: Piston pin is also called as gudgeon pin.Gudgeon pins are made of steel alloy of high strength. Gudgeon pins are short hollow pipes. Steel alloy of high strength are used for this pin because it should be very light and also have very high strength and temperature resistance.
4. Compression rings are fitted at the _________
a) Middle of skirt
b) Bottom of skirt
c) Top of skirt
d) None of the mentioned
Answer: c
Explanation: Compression rings are located at the top of skirt.
5. Piston rings are not completely closed because __________
a) Closed rings are hard to manufacture
b) Gap allows the ring to expand and fit over
c) They are designed to let pass some lubricant to the combustion chamber
d) None of the mentioned
Answer: b
Explanation: Piston rings expand due to heat of combustion and fit over.
6. The entrance of the piston pin hole is sealed by ____________
a) Steel plating
b) Snap ring
c) Rubber ring
d) None of the mentioned
Answer: b
Explanation: Snap rings are used to seal the entrance.
7. Compression rings have which type of cross section __________
a) Rectangular
b) L shaped
c) Keystone
d) All of the mentioned
Answer: d
Explanation: All the given are types of Compression ring cross sections.
8. Passenger car engines contain ____________
a) 2 compression ring and 1 oil control ring
b) 2 compression ring and 2 oil control ring
c) 1 compression ring and 1 oil control ring
d) 2 compression ring and no oil control ring
Answer: a
Explanation: These type of engines contain 2 compression ring and 1 oil control ring.
9. The function of a piston is ____________
a) It forms a movable wall of combustion chamber
b) It transmits turning force to the crankshaft via connecting rod
c) It functions like crosshead and transmits side thrusts
d) All of the mentioned
Answer: d
Explanation: A piston performs all the above mentioned functions.
10. If the diameter of a piston is ‘D’ then the length of skirt is usually of the range of ___________
a) 0.75D to 0.8D
b) 0.5D to D
c) 1.5D to 2D
d) 0.2D to 0.6D
Answer: a
Explanation: The length of the skirt is usually 0.75 to 0.8 times the diameter of the piston.
11. The plate which acts as a packing between cylinder block and cylinder head is called ________
a) Chaplet
b) Liner
c) Gasket
d) Flange
Answer: c
Explanation: Gasket forms the packing between cylinder block and cylinder head.
12. Which one of the following is a type of Gasket?
a) Copper asbestos
b) Steel asbestos
c) Single sheet rigid
d) All of the mentioned
Answer: d
Explanation: All the three are various types of gaskets.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “IC Engine Crankshaft and Camshaft”.
1. In a four stroke cycle engine camshaft revolves at ______ the crank speed.
a) Two times
b) Half
c) Four times
d) Three times
Answer: b
Explanation: The camshaft rotates at half of the crank speed.
2. The gears on camshaft and crankshaft are known as ________
a) Lining gears
b) Aligning gears
c) Timing gears
d) Tuning gears
Answer: c
Explanation: These gears are called timing gears. Timing gears connect camshaft to the crankshaft. Timing gears provide 2:1 gear reduction for four stroke engines.
3. The material known as high carbon high copper chrome silicon cast steel is used for making _________
a) Camshaft
b) Cylinder body
c) Cylinder head
d) Piston
Answer: a
Explanation: Material used for making camshafts is high carbon high copper chrome silicon cast steel.
4. Camshaft gear is made from which material?
a) Cast iron
b) Mild steel
c) Bakelite
d) Brass
Answer: c
Explanation: Camshaft gears are made from bakelite.
5. Crankshafts are usually constructed by ______
a) Casting
b) Drop forging
c) Drawing
d) Extrusion
Answer: b
Explanation: Drop forging is used for making crankshafts.
6. The main reasons for crankshaft wear are _______
a) Different loads at some points of rotation
b) Centrifugal forces due to crankshaft rotation
c) Misalignment in connecting rod
d) All of the mentioned
Answer: d
Explanation: All the three are the reasons for crankshaft wear.
7. The main causes of crankshaft vibration are _________
a) Variation in torque
b) Cyclic variation of gas and combustion products
c) Unbalanced weight of parts
d) All of the mentioned
Answer: d
Explanation: Crankshaft vibration is caused by all the above mentioned causes.
8. In the cam, the distance between the base circle and the nose is called ______
a) Lift
b) Lobe
c) Flank
d) Pitch
Answer: a
Explanation: Distance between the base circle and nose is called lift of cam.
9. The crankshaft rotates the camshaft using _______
a) Belt drive
b) Chain drive
c) Gear drive
d) Motor drive
Answer: b
Explanation: Chain drive is used to connect crankshaft and camshaft.
10. The crankshaft should be inspected for ______
a) Cracks
b) Alignment of crankpins and journals
c) Cleanliness of oil gallaries
d) All of the mentioned
Answer: d
Explanation: Crankshaft should be inspected for all the above mentioned faults.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Engine Valves and their Mechanisms”.
1. In a four stroke engine each cylinder has
a) One valve
b) Two valves
c) Three valves
d) Four valves
Answer: b
Explanation: A four stroke engine cylinder has one intake and one exhaust valve.
2. In a diesel engine the fuel injection pressure is in the range
a) 100 to 170 atm
b) 60 to 70 atm
c) 30 to 40 atm
d) 20 to 25 atm
Answer: a
Explanation: The pressure of fuel injection is very high for a diesel engine.
3. The valve is opened as the cam lobe on the cam raises the
a) Bearing
b) Piston
c) Valve lifter
d) Valve seat
Answer: c
Explanation: Valve opens when valve lifter is raised.
4. Exhaust valve temperature is about
a) 35 degree celsius
b) 100 degree celsius
c) 150 degree celsius
d) 500 degree celsius
Answer: d
Explanation: The temperature of the exhaust valve is of the order of 500 degree celsius.
5. The size of the engine intake valve is
a) Same as that of exhaust valve
b) Smaller than that of exhaust valve
c) Larger than that of exhaust valve
d) Does not depend upon the size of exhaust valve
Answer: b
Explanation: The exhaust valve is made bigger in size than the intake valve.
6. The device used to measure the clearance between the valve and tappet of an IC Engine is
a) Feeler gauge
b) Snap gauge
c) Slip gauge
d) Micrometer
Answer: a
Explanation: A Feeler gauge is used to measure the clearance.
7. The purpose of valve clearance is to
a) Allow the valve to expand
b) Allow the sliding of valve in the guide
c) Ensure that the valve closes fully
d) Ensure that the crankshaft is free to rotate
Answer: c
Explanation: Valve clearance ensures that valve closes completely.
8. The opening and closing of a valve is respectively done by
a) A cam and a spring
b) A spring and a cam
c) Gas pressure and cam
d) Cylinder vacuum and spring
Answer: a
Explanation: An engine valve is opened by a cam and closed by a spring.
9. On modern four stroke engines the exhaust valve opens just
a) Before TDC
b) After TDC
c) Before BDC
d) After BDC
Answer: c
Explanation: Exhaust valve opens before the piston reaches Bottom Dead Centre.
10. On modern four stroke engines the inlet valve opens just
a) Before TDC
b) After TDC
c) Before BDC
d) After BDC
Answer: a
Explanation: Inlet valve opens before the piston reaches Top Dead Centre.
11. A relief valve is fitted to the main oil gallery of an engine. The purpose of this valve is to
a) Limit the maximum oil pressure
b) Open when the oil is hot
c) Maintain the supply if the gallery becomes blocked
d) Stop the oil flow to the bearings
Answer: A relief valve limits the maximum oil pressure.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Fuel Injection Systems”.
1. In which of the following fuel injector is used?
a) Compression-ignition engines
b) Spark-ignition engines
c) Steam engines
d) Sterling engines
Answer: a
Explanation: In compression – ignition engines, only air is compressed in the cylinder and by means of fuel – injection system fuel is injected into the cylinder. In CI engines, compressed air temperature plays a main role in combustion.
2. At which stroke the fuel is injected in the CI engine?
a) Suction stroke
b) Compression stroke
c) Expansion stroke
d) Exhaust stroke
Answer: b
Explanation: Fuel injection in the CI engines start at the end of the compression stroke. Fuel is injected directly into the combustion chamber.
3. Which of the following is the port fuel – injection system?
a) D – MPFI
b) L – MPFI
c) GDI
d) TBI
Answer: b
Explanation: L – MPFI system uses port fuel – injection. In this, the fuel metering is regulated by the speed of the engine and the amount of air that actually enters the engine. D – MPFI system uses manifold injection. GDI system uses direct injection. TBI system uses throttle body injection.
4. What is the range of pressure is achieved in the injection pump?
a) 120 – 200 bar
b) 10 – 20 bar
c) 400 – 500 bar
d) < 10bar
Answer: a
Explanation: The purpose of the fuel injection pump is to increase the pressure of the quantity of fuel in the range of 120 – 200 bars and deliver it at the correct instant to the injector.
5. In pneumatic governor, which of the following control the amount of vacuum applied to the diaphragm?
a) Spring
b) Accelerator pedal
c) Butterfly valve
d) Lever
Answer: a
Explanation: The vacuum applied to the diaphragm is controlled by the accelerator pedal. The diaphragm is in contact with the fuel pump control rack.
6. A six-cylinder, four-stroke diesel engine develops a power of 200 kW at 2000 revolution per minute. The brake specific fuel consumption is 0.3 kg / kW – h. What is the time for injection if the injection takes place over 20° crank angle?
a) 1 millisecond
b) 2 milliseconds
c) 1.5 milliseconds
d) 1.66 milliseconds
Answer: d
Explanation: Power output / cylinder = 200 / 6 = 33.33 kW. Fuel consumption / cylinder = 33.33 * brake specific fuel consumption = 33.33 * 0.3 = 9.99 kg / h. Time for injection = / = 1.667 * 10 -3 sec = 1.66 milliseconds.
7. What is the spray cone angle in the Pintle nozzle?
a) 60°
b) 15°
c) 25°
d) 45°
Answer: a
Explanation: Spray cone angle of a Pintle nozzle is 60°. The main advantage of this nozzle is that it avoids weak injection and dribbling. Also, it prevents the carbon deposition on the nozzle hole.
8. Which of the following is not the part of the injector assembly?
a) Needle valve
b) Nozzle
c) Diaphragm
d) Compressor spring
Answer: c
Explanation: The injector assembly consists of a needle valve, nozzle, compressor spring, and an injector body. The diaphragm is a part of the injection pump governor. A nozzle is used to atomize the fuel and break up into small particles.
9. Which of the following is not the function of the fuel injection system?
a) Time the fuel injection
b) Filter the fuel
c) Atomize the fuel to fine particles
d) Control the engine speed
Answer: d
Explanation: The functions of the fuel injection system are to filter the fuel, to time the fuel injection, to break up the fuel into small particles.
10. The cold start injector provides a lean air-fuel ratio.
a) True
b) False
Answer: b
Explanation: The cold start injector gives a rich air-fuel ratio. Its objective is to supply the engine with additional fuel to make the rich mixture in cold temperatures where the air density is increased and additional fuel is required.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Flywheel”.
1. What is the maximum fluctuation of energy?
a) It is the sum of maximum and minimum energies
b) It is the ratio of the maximum and minimum energies
c) It is the ratio of the mean resisting torque to the work done per cycle
d) It is the difference between the maximum and minimum energies
Answer: d
Explanation: The maximum fluctuation of energy is the difference between the maximum and minimum energies. The fluctuation of energy can be found out by the turning moment diagram for one complete cycle of operation.
2. What is the coefficient of fluctuation of energy?
a) The ratio of the maximum fluctuation of energy to the minimum fluctuation of energy
b) The ratio of the maximum fluctuation of energy to the work done per cycle
c) The ratio of the minimum fluctuation of energy to the maximum fluctuation of energy
d) The ratio of the work done per cycle to the maximum fluctuation of energy
Answer: b
Explanation: The coefficient of fluctuation of energy (C E ) is the ratio of the maximum fluctuation of energy to the work done per cycle. C E =\(\frac{\Delta E}{T_{mean} \theta}\) where ΔE = maximum fluctuation of energy, T mean *θ = work done per cycle, T mean = mean torque, and θ = angle turned in radian in one cycle.
3. Which of the following is true about the flywheel?
a) Flywheel regulates speed over a period of time
b) Flywheel takes care of the quantity of fluid
c) Flywheel controls \
Flywheel regulates the speed by regulating the quantity of charge of the prime mover
Answer: c
Explanation: Flywheel controls the rate of fluctuation of the speed during a cycle. Flywheel controls the speed in one cycle. It does not control the supply of fuel to the engine.
4. Given that maximum fluctuation of energy is 2000 N-m/s and coefficient of fluctuation of speed is 0.02. What is the mean kinetic energy of flywheel?
a) 50 kN-m/s
b) 40 kN-m/s
c) 30 kN-m/s
d) 20 kN-m/s
Answer: a
Explanation: The maximum fluctuation of energy in a flywheel = ΔE, mean kinetic energy of the flywheel = E, and coefficient of fluctuation of speed = C s . ΔE = 2*E*C s ⇒ 2000 = 2*E*0.02 ⇒ E = 50 kN-m/s.
5. What is the coefficient of fluctuation of speed?
a) The ratio of the maximum fluctuation of speed to the mean speed
b) The ratio of the maximum fluctuation of energy to the mean speed
c) The ratio of the minimum fluctuation of energy to the mean speed
d) The ratio of the work done per cycle to the mean speed
Answer: a
Explanation: The coefficient of fluctuation of speed is the ratio of the maximum fluctuation of speed to the mean speed. C s = (ω 1 – ω 2 )/ω =2 (ω 1 – ω 2 ) / (ω 1 +ω 2 ) or C s = 2(N 1 -N 2 ) / (N 1 +N 2 ).
6. Which of the following is the expression of the maximum fluctuation of energy in a flywheel where I = mass moment of inertia of the flywheel, C s = coefficient of fluctuation of speed, ω = mean angular speed of ω 1 and ω 2 , and E = mean kinetic energy of the flywheel?
a) I*ω*(ω 1 +ω 2 )
b) I*ω*C s
c) 2*E 2 *C s
d) I*ω 2 *C s
Answer: d
Explanation: The maximum fluctuation of energy in a flywheel = I*ω*(ω 1 -ω 2 ) = I*ω 2 *C s = 2*E*C s = I*ω 2 *C s . The maximum fluctuation of energy can be calculated by using the turning moment diagram.
7. In the single-cylinder, single acting, four-stroke gas engine, the total fluctuation of speed is not to exceed ±3 percent of the mean speed. What is the coefficient of fluctuation of speed?
a) 0.04
b) 0.03
c) 0.09
d) 0.06
Answer: d
Explanation: Since the total fluctuation of speed is not to exceed ±3 percent of the mean speed, therefore ω 1 – ω 2 = 6% ω and coefficient of fluctuation of speed = C s = (ω 1 – ω 2 )/ω = 0.06.
8. The steam engine has a flywheel which is having a radius of gyration of 1.1 m and mass of 2200 kg. The starting torque is 1550 Nm and assumed constant. What is the angular acceleration of the flywheel?
a) 0.54 rad/s 2
b) 0.58 rad/s 2
c) 0.62 rad/s 2
d) 0.52 rad/s 2
Answer: b
Explanation: I = mass moment of inertia of the flywheel, m = mass of the flywheel, k = radius of gyration, T = stating torque, and α = angular acceleration of the flywheel. I = m*k 2 = 2200*1.1 2 = 2662 kg-m 2 . T = I*α ⇒ 1550 = 2662 * α ⇒ α = 0.58 rad/s 2 .
9. The engine has the flywheel of mass 7 tons and the radius of gyration is 1.7 m. The fluctuation of energy is 55 kN-m. The mean speed of the engine is 150 rpm. What is the coefficient of fluctuation of speed?
a) 0.021
b) 0.011
c) 0.031
d) 0.041
Answer: b
Explanation: The fluctuation of energy = ΔE, the mass of the flywheel = m, the radius of gyration = k, the mean speed of the flywheel = N. ΔE = \(\frac{π^2}{900}\)*m*k 2 *N*(N 1 -N 2 ) = \(\frac{π^2}{900}\)*7000*1.7 2 *150*(N 1 -N 2 ) = 33277*(N 1 -N 2 ) ⇒ 55000 = 33277*(N 1 -N 2 ) ⇒ (N 1 -N 2 )= \(\frac{55000}{33277}\) = 1.652 rpm. Coefficient of fluctuation of speed = C s = \(\frac{N_1-N_2}{N}\) = \(\frac{1.652}{150}\) = 0.011.
10. The flywheel stores the potential energy.
a) True
b) False
Answer: b
Explanation: The flywheel stores the rotational energy. The amount of energy that flywheel can store is proportional to the square of the mass and its rotational velocity. The lighter flywheels are used in a sports car for easy and quick recovery of the RPM.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “2 Stroke Engines”.
1. How can a two-stroke engine identify by?
a) Piston size
b) Absence of valves
c) Cooling system
d) Lubrication system
Answer: b
Explanation: The two-stroke engine is identified by the absence of valves. Almost all two-stroke engines do not have valves. This makes the two-stroke engine easy to produce and maintain.
2. Which of the following is not an advantage of a two-stroke engine?
a) Not valves
b) Lighter flywheel
c) More uniform torque
d) No lubrication system
Answer: d
Explanation: The two-stroke engines do not have valves. Due to which it makes them easy to manufacture. Also, the two-stroke engine has a lighter flywheel. That is the reason the two-stroke engine produces the more uniform torque.
3. Which of the following is the most perfect method of scavenging?
a) Reverse flow scavenging
b) Loop scavenging
c) Uniform scavenging
d) Cross scavenging
Answer: c
Explanation: Uniform scavenging is the most perfect method of scavenging. In uniform scavenging, both fresh charge and burnt gases move in the same direction.
4. Which method of scavenging is used in two-wheelers without deflector type piston?
a) Cross scavenging
b) Reverse flow scavenging
c) Uniform scavenging
d) Loop scavenging
Answer: a
Explanation: Cross scavenging is used in two-wheelers without deflector type piston. In this, the fresh charge is directed upward, and then down to force out the exhaust gases through the oppositely positioned exhaust port.
5. How much power will two-stroke engine of the same size as the four-stroke engine develop at the same speed?
a) Four times the power
b) Twice the power
c) Half the power
d) Same power
Answer: b
Explanation: The two-stroke engine produces twice the power produced by the four-stroke engine. The power stroke happens in every one revolution in a two-stroke engine.
6. What is the delivery ratio of the crankcase scavenged engine?
a) Greater than 1
b) Less than 1
c) Equal to 1
d) Greater than 2
Answer: c
Explanation: The delivery ratio is the ratio of the air delivered to the reference volume or ratio of the mass of fresh air delivered to the reference mass. R del = V del / V ref or R del = M del /M ref . The delivery ratio usually varies between 1.2 and 1.5 except for crankcase scavenged engines it is less than 1.
7. What is the excess air factor in the case of a two-stroke engine if the delivery ratio is 1.7?
a) 1.0
b) 0.8
c) 0.7
d) 0.9
Answer: c
Explanation: Delivery ratio = R del = 1.7, excess sir factor = λ. The relation between the R del and λ is λ = R del – 1 = 1.7 – 1 = 0.7. The delivery ratio is the ratio of the air delivered to the reference volume or ratio of the mass of fresh air delivered to the reference mass. R del = V del / V ref or R del = M del / M ref .
8. What is the scavenging efficiency for the perfect mixing if the delivery ratio is 1.5?
a) 80.73%
b) 81.73%
c) 82.73%
d) 84.73%
Answer: b
Explanation: Delivery ratio = R = 1.7 and scavenging efficiency = η sc . The relation between the R and η sc is η sc = 1 – e -R = 1 – e -1.7 = 1 – 0.1826 = 0.8173 = 81.73%. In perfect mixing, the incoming fresh charge mixes completely and instantaneously with the cylinder contents. A portion which is mixed gets passed out at a rate equal to that of charge entering the cylinder.
9. For two-stroke SI engine, the scavenging efficiency is 0.5, cylinder volume of 1200 cc and the scavenging density is 1.3 kg/m 3 . What is the mass flow rate of air per cycle?
a) 0.00072 kg/cycle
b) 0.00076 kg/cycle
c) 0.00074 kg/cycle
d) 0.00084 kg/cycle
Answer: a
Explanation: Scavenging density = ρ sc = 1.3 kg/m 3 , total cylinder volume = V tot = 1200cc, mass flow rate of air = ṁ a and the scavenging efficiency = η sc = 0.5, η sc = ṁ a / (V tot * ρ sc ) = ṁ a = V tot * ρ sc * η sc = 0.0012 * 1.3 * 0.5 = 0.00072 kg/cycle.
10. The two-stroke engine is easy to manufacture.
a) True
b) False
Answer: a
Explanation: Since the two-stroke engine has no valves and valve actuating mechanism, it is simple in making. This makes it easy to manufacture. Also, the flywheel in the two-stroke engine is lighter.
This set of Automobile Engineering online quiz focuses on “Cylinder Block”.
1. _________ serve as a support and enclosure for moving parts.
a) cylinder block
b) cylinder head
c) crank case
d) connecting rod
Answer: a
Explanation: Because cylinder block is outer body of the engine which encloses all other parts like piston, connecting rod etc.
2. In modern engines cylinder block and crank case forms a single casting because _________
a) reduces space consumption
b) rigid structure
c) wearing properties
d) can withstand high temperature
Answer: b
Explanation: Cylinder block and crank case are made of single casting to make them a rigid structure since they should withstand high temperature and to have good wear properties.
3. _______ are cast in crankcase to give extra strength and to support camshaft bearings.
a) rocker arm
b) oil filter
c) rims
d) manifolds
Answer: c
Explanation: Since rims forms/gives an outer layer for crankcase they are used besides they too have high wear properties.
4. A separate _______ crankcase would result in saving weight also enabling cheaper and quick replacement.
a) nickel
b) chromium
c) iron
d) aluminium
Answer: d
Explanation: Aluminium is of lighter weight and is easily available in the market so which can be replaced easily with comparatively lower price.
5. Which of the following isn’t a cylinder block part?
a) cylinder in which piston slides up and down
b) openings for valves
c) passages for flow of cooling water
d) carburettor
Answer: d
Explanation: Carburettor isn’t a part of cylinder block it is used for mixture of fuel and air and then allowed to the intake port.
6. Cylinder block is usually made from _________
a) grey cast iron
b) steel sleeves
c) nickel
d) chromium
Answer: a
Explanation: Since cylinder block has to withstand more sliding of piston the material should be good in wearing properties so grey cast iron material is used for cylinder block.
7. In some small engines, the cylinder walls are plated with __________ to reduce wall wear and increase the service life.
a) grey cast iron
b) steel sleeves
c) chromium
d) nickel
Answer: c
Explanation: Chromium a very hard metal with high coefficient of thermal expansion so used to reduce wall wear and to promote service life.
8. Which of the following is advantage for aluminium alloy cylinder block over grey cast iron?
a) density
b) machinability
c) co-efficient of thermal expansion
d) thermal conductivity
Answer: a
Explanation: Density of aluminium is one-third of cast iron and it is a light weight material which is advantage over cast iron.
9. By which relation speed of piston can be calculated inside cylinder block?
a) 2LDN
b) 2LN
c) 2πLD
d) 2πL
Answer: b
Explanation: Because in cylinder block when piston oscillates up and down it takes twice the length and with speed the engine rotates so it is 2LN.
10. Bubbles of air in radiator is sign of _________ problem.
a) cracked block
b) blown head gasket
c) seized block
d) lack of engine oil
Answer: b
Explanation: Bubbles of air in radiator is sign of blown head gasket which is a rare case occurring in cylinder head for which remedy is replacement of gasket, which requires an elevated platform for lifting engine.
This set of Automobile Engineering Question Bank focuses on “Cylinder Head”.
1. Spark plug are mounted inside ________
a) cylinder block
b) cylinder head
c) crank case
d) piston
Answer: b
Explanation: Spark plugs are mounted inside cylinder head because it is consists of combustion chamber and sometimes valves are also mounted.
2. Which of the following provides passages for flow of cooling water?
a) cylinder block
b) cylinder head
c) crank case
d) piston
Answer: b
Explanation: Since cylinder head only consists of the combustion chamber which in turn connects with the cooling water passages for cooling down of the engine or to prevent the over heating of engine.
3. For retaining compression in the cylinder, a flat piece of ___________ is placed between the cylinder head and cylinder block.
a) gasket
b) rims
c) cylinder liner
d) invar strut
Answer: a
Explanation: Gaskets are coated with special varnish which melts and seals all the small inter sticks of the block and head when the engines warms up. The gaskets besides withstanding high pressure should also withstand high temperature also.
4. The main advantage of using aluminium alloy for cylinder head is ____________
a) lightness in weight
b) high thermal conductivity
c) less corrosion rate
d) cost
Answer: b
Explanation: Generally cylinder heads are coated with grey cast iron and aluminium alloy. The main advantage for the aluminium alloy over the cast iron is high thermal conductivity which can withstand about 1000°C without much expansion and deformation.
5. Inter-metallic corrosion between steel studs and aluminium alloy lead to ___________
a) engine war-up
b) higher fuel consumption
c) cylinder head stick to cylinder block
d) gaskets get damaged
Answer: c
Explanation: Due to corrosion and over heating of the engine due to the piston sliding movements up and down, the cylinder block will get attached to the cylinder block which in turns lead to total replacement of the entire engine setup.
6. Why cylinder head cast as a separate piece?
a) good compression ratio
b) high efficiency
c) prevent collision
d) easy removal
Answer: d
Explanation: Cylinder head are casted as separate piece generally for easy removal also to provide correct provision for spark plug, injector, flow of water etc.,
7. ____________ is combination of fibre and cork granules that is more compressible and resilient.
a) karropak
b) felicoid
c) shimbestos
d) metal sandwich
Answer: b
Explanation: Felicod is a type of pump gasket which is improvement on cork. It is less subject to shrinkage and expansion. It can also withstand considerable bending and twisting without breakage.
8. Which of the following oil pan gaskets are not affected by oil and grease?
a) felbestos
b) metal encased
c) felcoperne
d) felicod
Answer: c
Explanation: Felcoperne is synthetic rubber compound with good resilient and compressible. It is not affected by expansion or shrinkage. Compared to other oil pan gaskets like cork and felicod felcoperene is preferred now-a-days.
9. Which of the following is not the type of manifold gaskets?
a) felbestos
b) metal encased
c) metal embosed
d) shimbestos
Answer: d
Explanation: Shimbestos is a cylinder gaskets which is combination of thin steel heat shield on one side and a high resilient specially treated metal reinforced asbestos on the top.
10. ____________ is attached to the bottom face of cylinder block.
a) crank case
b) oil pan
c) piston
d) cylinder liners
Answer: a
Explanation: Crank case is attached to the bottom part of the cylinder block which serves as a base of engine, which supports crankshaft and camshaft in suitable bearings also provides an arm for supporting engine on frame.
11. The cylinder block and upper half of the crank case are cast by _________ material.
a) aluminium
b) zinc
c) semi-steel
d) titanium
Answer: c
Explanation: Semi-steel provides a strong and harder casting also good thermal conductivity, which permits thin casting walls and improving cooling.
12. _________ serves as a cooling and ventilation of engine lubricating oil.
a) crank case
b) oil sump
c) cam shaft
d) piston
Answer: b
Explanation: Oil sump or oil pan which is bottom half of crank case it is bolted or screwed to the lower flange of main casting.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Wheel and Tire”.
1. Which types of wheels cannot be used with a tubeless tire?
a) Disc wheel
b) Light alloy wheel
c) Wire wheel
d) Composite wheel
Answer: c
Explanation: Wire wheels cannot be used with a tubeless tire. Wire wheels are expensive due to their construction. The rim of a wired wheel has holes, due to which it is not possible to fit tubeless tires on wire wheels.
2. Which type of wheels is preferred in sports cars?
a) Disc wheel
b) Wire wheel
c) Magnesium alloy wheel
d) Aluminum alloy wheel
Answer: c
Explanation: Magnesium alloy wheels are preferred in sports cars. Magnesium alloy wheels have high impact and fatigue strength so that they can stand vibration and shock loading better.
3. In case of a wire wheel, the vehicle weight is supported by the wire in _________
a) Tension
b) Bending
c) Shear
d) Compression
Answer: a
Explanation: The vehicle weight is supported by the wire in tension in case of a wire wheel. The side forces on cornering are taken up by the spoke forming triangular arrangement.
4. What does the ‘ply rating’ refer to?
a) Aspect ratio
b) Rated strength
c) Recommended inflation pressure
d) The actual number of plies
Answer: b
Explanation: The ‘ply rating’ refers to rated strength. It is referred to the number of layers of cotton from which the ply is made. The ply rating is high that means the size of the tire is tough.
5. Where will an underinflated tire wear the thread most?
a) Near center
b) Near the edge
c) In the cross direction
d) In the lateral direction
Answer: b
Explanation: An underinflated tire will wear the thread near the edge most. It is sometimes visible in the shape of sidewall cracking.
6. Where will an overinflated tire wear the thread most?
a) Near center
b) Near the edge
c) In the cross direction
d) In the lateral direction
Answer: a
Explanation: An overinflated tire will wear the thread near the center. This type of tire break is caused when an object is hit with a force.
7. What do the permissible of mixing cross-ply and radial-ply automobile tires allow?
a) Cross-ply tires on left wheels
b) Cross-ply tires on right wheels
c) Cross-ply tires on front wheels
d) Cross-ply tires on rear wheels
Answer: c
Explanation: The permissible of mixing cross-ply and radial-ply automobile tires allow cross-ply tires on front wheels. In cross-ply type tires, the ply cords are woven at an angle to the tire axis.
8. What is the purpose of tire rotation on automobiles?
a) Avoid ply separation
b) Equalize wear
c) Get better ride
d) Reduce bump
Answer: b
Explanation: Equalize wear is the purpose of tire rotation on automobiles. The advantage of tires wearing uniformly is wear reduces a tire’s tread depth equally if all the tires wear at the same rate.
9. A car is fitted with 6 * 14 wheels and 185/65 R 14 tires on them. What is the rolling radius of the original tire?
a) 398.05 mm
b) 298.05 mm
c) 288.05 mm
d) 278.05 mm
Answer: b
Explanation: Radius of the wheel = ½ * 14 = 7 in = 177.8 mm. Section height of tire = 0.65 * 185 = 120.25 mm. Rolling radius of the original tires = 177.8 + 120.25 = 298.05 mm.
10. What does the code 145 SR -13 tire designation represent?
a) 145” width, 13” diameter, cross-ply
b) 145 mm width, 13” diameter, radial-ply
c) 145” width, 13 cm diameter, radial-ply
d) 145 mm width, 13 cm diameter, cross-ply
Answer: b
Explanation: The tire designation is of the form width , speed rating, type of ply, and diameter in the same order. So 145 SR – 13 signifies that width = W = 145 mm, speed rating = S which is up to 170 Kmph, the ply is of radial type, and diameter = 13” or 13 in = 330 mm.
This set of Automobile Engineering Assessment Questions and Answers focuses on “Supercharging of IC Engines”.
1. What is the purpose of the supercharger?
a) To increase the pressure
b) To increase the speed of the engine
c) To increase the gear ratio
d) To increase the cooling rate
Answer: a
Explanation: The purpose of the supercharger is to increase the pressure of the charge. Brake power = \(\frac{brake\, mean\, effective\, pressure \,X \,swept\, volume\, X\, no.of \,cylinder\, X\, no.of \,power \,strokes}{60000}\) . From the formula, by increasing the brake mean effective pressure brake power can be increased.
2. Which of the following is not the effect of supercharging?
a) Improved cold starting
b) Increased gas loading
c) Reduced exhaust smoke
d) Increased thermal loads
Answer: d
Explanation: The supercharging used for an improved cold start, increased gas loading, reduced exhaust smoke, increased mechanical efficiency, etc. The disadvantage of the supercharger is that it uses the crankshaft of the engine to drive.
3. When the supercharger draws power from engine exhaust gases with the help of gas turbine, what is the supercharger called?
a) Turbocharger
b) Vane type supercharger
c) Root’s supercharger
d) Centrifugal type supercharger
Answer: a
Explanation: The supercharger which uses the engine exhaust gases for increasing the brake power is called the turbocharger. The frictional and thermal losses are less.
4. Which type of supercharger is used at low speeds?
a) Centrifugal type supercharger
b) Vane type supercharger
c) Root’s supercharger
d) Twin-screw supercharger
Answer: a
Explanation: Centrifugal type supercharger is used at low speeds. The belt from the engine drives the supercharger. The mixture coming out of the supercharger is at high pressure.
5. Which of the following is the advantage of Root’s supercharger?
a) It occupies less space
b) It consumes less power
c) It has minimum maintenance
d) It produces high pressure
Answer: c
Explanation: One of the advantages of Root’s supercharger is that it has minimal maintenance. Root’s supercharger works similar to the gear pump. It consists of two rotors which are connected to each other by means of gear.
6. How does the supercharger increase power output?
a) By increasing the charge pressure
b) By increasing the charge temperature
c) By increasing the speed of the engine
d) By increasing the quantity of fuel admitted
Answer: a
Explanation: The supercharger increases the power output of the engine by increasing the charge pressure. The brake of the engine depends on the brake mean effective pressure.
7. What is used to run the supercharging air compressor?
a) Separate electric motor
b) Engine
c) Exhaust gas turbine
d) Gear pump
Answer: b
Explanation: Engine is used to run mechanically driven supercharger. The engine crankshaft is coupled with the air compressor of the supercharger which drives the air compressor in the supercharger.
8. Why is there a need for charge cooling?
a) To increase the engine operating temperature
b) To reduce the engine operating temperature
c) To decrease the density of air
d) To increase the exhaust temperature
Answer: a
Explanation: When the air in the supercharger gets compressed, it gets hot. Its temperature gets increased more than the ambient air temperature.
9. What is the brake power if the swept volume is 3.5 liters, brake mean effective pressure is 10 bars, and speed is 6000 rpm?
a) 175 kW
b) 17.5 kW
c) 1.75 kW
d) 1750 kW
Answer: a
Explanation: Given swept volume = 3.5 liters, brake mean effective pressure = 10 bars & speed = 6000 rpm.
Brake power = \(\frac{brake \,mean \,effective \,pressure \,X \,swept \,volume \,X \,no.of \,cylinder \,X \,no.of \,power \,strokes}{60000} \)
= \(\frac{3.5 × 10 × 10^5 × 6000}{1000 × 60000 × 2}\) = 175 kW.
10. The turbocharger makes use of the power from the engine so that it increases the pressure.
a) True
b) False
Answer: b
Explanation: The turbocharger makes use of the exhaust gases from the engine to drive the gas turbine. In this type of supercharger, there is no linkage between the turbocharger and the engine.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Carburettors”.
1. What is the stoichiometric air-fuel ratio of diesel?
a) 50: 1
b) 14.7: 1
c) 25: 1
d) 14.5: 1
Answer: d
Explanation: The stoichiometric air-fuel ratio of diesel is 14.5: 1. The stoichiometric air-fuel ratio of petrol is 14.7: 1. The mixture which contains less air than the stoichiometric requirement is called a rich mixture.
2. What is the purpose of the venturi in the carburetor?
a) To decrease the fuel flow
b) To increase the manifold vacuum
c) To increase the air velocity
d) To decrease the air velocity
Answer: d
Explanation: The purpose of the venturi in the carburetor is to increase the air velocity. The venturi in carburetors is used to measure airflow in an engine.
3. When does the simple carburetor supplies rich mixture?
a) Idling
b) Cruising
c) Accelerating
d) Starting
Answer: c
Explanation: The simple carburetor supplies the rich mixture during accelerating. During acceleration, the engine requires more amount of fuel to get the high speed of the vehicle due to which there is a requirement of the rich mixture.
4. To burn 1 kg of octane completely, how much amount of air is required?
a) 14.12 kg
b) 15.12 kg
c) 16.12 kg
d) 10.12 kg
Answer: b
Explanation: Complete combustion means all carbon in the fuel is converted to CO 2 and all hydrogen to H 2 O. To burn one kg of octane (C 8 H 18 ) completely 15.12 kg of air is required. Hence the correct Air Fuel ratio is 15.12: 1. Sometimes, it is approximated to 15: 1.
5. Which type of carburetor is a constant vacuum carburetor?
a) Zenith
b) Solex
c) S. U.
d) Carter
Answer: c
Explanation: S. U. carburetor is a constant vacuum carburetor. Solex, Carter, and Zenith are a type of constant choke carburetor.
6. A four-stroke gasoline engine of 1.9-liter capacity is to develop maximum power at 6000 revolutions per minute. The volumetric efficiency is 80%. What is the actual volume of air sucked per second?
a) 0.053 m 3 /s
b) 0.076 m 3 /s
c) 0.046 m 3 /s
d) 0.089 m 3 /s
Answer: b
Explanation: Actual volume of air sucked per second = efficiency * volume of engine * * = 0.8 * 1.9 * 10 -3 * * = 0.076 m 3 /s.
7. The principle of compensating jet device is to make the mixture leaner as the throttle opens progressively.
a) True
b) False
Answer: a
Explanation: Most of the times the compensating jet is incorporated in the carburetor with the main jet. The compensating jet makes the mixture leaner as the main jet makes the mixture richer.
8. Which of the following is not the part of a carburetor?
a) Float chamber
b) Choke and throttle
c) Fuel strainer
d) Auxiliary valve
Answer: d
Explanation: A carburetor consists of fuel strainer, float chamber, choke, throttle, main fuel metering, and idling nozzles. The auxiliary valve is one of the compensating devices.
9. Which type of carburetor the Solex is?
a) Constant choke carburetor
b) Constant vacuum carburetor
c) Multiple venturi carburetors
d) Multijet carburetor
Answer: a
Explanation: Solex carburetor is a constant vacuum carburetor. Other constant vacuum carburetors are Zenith and Carter. S. U. carburetor is a type of constant choke carburetor.
10. In multiple venturi carburetors, the main jet discharges the fuel in a downward direction into the primary venturi against the upward air stream.
a) True
b) False
Answer: b
Explanation: In multiple venturi carburetors, the main jet discharges the fuel in an upward direction into the primary venturi against the downward air stream. The fuel atomized by the air stream.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Petrol Engine Fuel System”.
1. When is the choke used in the engine?
a) When the vehicle is idling
b) When the vehicle is accelerating
c) When the engine is cold
d) When the engine is hot
Answer: c
Explanation: The choke is used when the engine is cold. The choke is a butterfly valve located between the entrance to the carburetor and the venturi throat.
2. What does the venturi in carburetor cause?
a) Increase of air velocity
b) A decrease in air velocity
c) A decrease in fuel flow
d) Decrease of manifold vacuum
Answer: a
Explanation: The venturi in carburetor causes an increase in air velocity. The main function of the carburetor are to keep a reserve of fuel at a constant head.
3. Where is the lean air-fuel mixture needed?
a) During starting
b) During idling
c) During acceleration
d) During cruising
Answer: d
Explanation: The lean air-fuel mixture is needed during cruising. In this range, it is desirable that the carburetor provides the engine with the best fuel economy.
4. Which of the following is the most widely used fuel supply system?
a) Gravity system
b) Pressure system
c) Pump system
d) Vacuum system
Answer: c
Explanation: The most widely used fuel supply system is the pump system. In this system, a steel pipe carries petrol to the fuel pump which pumps into the float chamber through a flexible pipe.
5. Why is the small hole provided in the pump body?
a) A vent for the oil
b) A vent for water
c) A vent for air
d) A vent for the fuel
Answer: c
Explanation: The small hole is provided as a vent for air in the pump body. This is an escape for excess air in the pump. So that pump does not get overloaded.
6. Which of the following is the most accurate petrol injection system?
a) Manifold injection
b) Port injection
c) Throttle body injection
d) Direct injection
Answer: b
Explanation: The most accurate petrol injection system is port injection. In this system, the injector sprays the fuel into each intake port on the manifold side of the inlet valve.
7. Where does the power for mechanical fuel pump come from?
a) Camshaft
b) Crankshaft
c) Distributor shaft
d) Propeller shaft
Answer: a
Explanation: The power for mechanical fuel pump comes from the camshaft by means of an eccentric cam.
8. If petrol has a density of 800 kg/m 3 and the discharge nozzle is located 8 mm above the level of petrol in a float chamber. What is the pressure differential causing airflow?
a) 62.78 Pa
b) 42.78 Pa
c) 52.78 Pa
d) 72.78 Pa
Answer: a
Explanation: When the fuel flow just starts ΔP f = 0 i.e. ΔP a – ghρ f = 0. (ΔP f = pressure differential causing fuel flow, ΔP a = pressure differential causing airflow, h = height of nozzle above the fuel level, ρ f = density of fuel) ΔP a – 9.81*(8*10 -3 )*800 = 0 i.e. ΔP a = 62.78 Pa.
9. What is the pressure differential causing fuel flow if the venturi depression is found to be 105 cm of water?
a) 10300.5 Pa
b) 20300.5 Pa
c) 50300.5 Pa
d) 60300.5 Pa
Answer: a
Explanation: Pressure differential causing fuel flow = ΔP f , ρ = density of water, h = height of nozzle above the fuel level. ΔP f = g*h*ρ = 9.81*1.05*1000 = 10300.5 kg/m 2 .
10. What is the value of the rate of flow of fuel if the coefficient discharge of fuel is 0.75, area of the jet is 0.885 mm 2 , density of the fuel is 780 kg/m 3 , and pressure differential causing fuel flow is 15000 Pa?
a) 3.21 g/s
b) 4.21 g/s
c) 5.21 g/s
d) 6.21 g/s
Answer: a
Explanation: Pressure differential causing fuel flow = ΔP = 15000 Pa, coefficient of discharge = C f = 0.75, density of the fuel = ρ = 780 kg/m 3 , and area of the jet = A = 0.885 mm 2 . The rate of flow of fuel = W f = A* C f *\(\sqrt{2\rho\Delta P}\) = 0.885*0.75*10 -6 *\(\sqrt{2*780*15000}\) = 3.21*10 -3 kg/s = 3.21g/s.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Lubrication Systems”.
1. Which type of lubrication system is used in two-stroke engine?
a) Mist lubrication system
b) Wet sump lubrication system
c) Dry sump lubrication system
d) Splash lubrication system
Answer: a
Explanation: The mist lubrication system is used where crankcase lubrication is not suitable. In a two-stroke engine, as the charge is compressed in the crankcase, it is not possible to have the lubricating oil in the sump.
2. In most automobiles, which lubrication system is commonly used?
a) Splash system
b) Pressure system
c) Petrol system
d) Gravity system
Answer: b
Explanation: Pressure type lubrication is used commonly in most automobiles. In this system, oil is drawn in from the sump and forced to all the main bearings of the crankshaft through distributing channels.
3. The pressure inside the lubrication system is controlled by ______
a) Oil pump
b) Oil filter
c) Relief valve
d) Supply voltage
Answer: c
Explanation: The pressure inside the lubrication system is controlled by a relief valve. In the dry-sump lubrication system, if the filter is clogged, the pressure relief valve opens permitting oil to bypass the filter and reaches the supply tank.
4. What is the need for crankcase ventilation?
a) To cool cylinder
b) To cool crankcase
c) To cool piston
d) To remove blow-by
Answer: d
Explanation: The gas inside the cylinder gets past the piston rings and then it enters the crankcase. It contains water and sulphuric acid (H 2 SO 4 ).
5. Why are the detergents used as oil additives?
a) To increase fire point
b) To prevent foaming
c) To prevent sludge formation
d) To reduce viscosity
Answer: c
Explanation: The detergents are added to the oil as additives to increase the detergency. Detergency means property of an oil to clean the engine deposits.
6. Which of the following is the most important property of the lubricant?
a) Density
b) Thermal conductivity
c) Viscosity
d) Melting point
Answer: c
Explanation: Viscosity is the most important property of the lubricant. The viscosity of the oil at a given temperature and pressure must be compatible to ensure the hydrodynamic lubrication.
7. Which of the following viscosity indices shows the larger changes in viscosity with temperature?
a) 50
b) 100
c) 45
d) 10
Answer: d
Explanation: The high viscosity index number indicates relatively a smaller change in viscosity with temperature. A low viscosity number for given oil indicates a relatively large change of viscosity.
8. Which of the following of oils is multi-grade oil?
a) SAE 10W 30
b) SAE 25W
c) SAE 10
d) SAE 20W
Answer: a
Explanation: The SAE designation for multi-grade oils includes two viscosity. The first number indicates the relative flowability and the second number indicates the resistances to film break down.
9. Which of the following oils has the highest viscosity?
a) SAE 20
b) SAE 10
c) SAE 50
d) SAE 45
Answer: c
Explanation: Higher the SAE grade, higher the viscosity. Since SAE 50 has 50 grade hence it as highest viscosity amongst the other oils. SAE 50 is single non -winter-grade oil as there is no ‘W’ in the designation.
10. The vegetable oils are used as lubricants in the automobiles.
a) True
b) False
Answer: b
Explanation: The mineral oils are used as lubricants in the automobiles. The mineral oils are having properties such as to reduce the friction and wear between two metal contact and moving parts, to provide the sealing the action.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Transmission System – Clutches”.
1. If there are 7 clutch plates in a multi-plate clutch, what is the number of pair of contact surfaces?
a) 5
b) 4
c) 6
d) 8
Answer: c
Explanation: If ‘n’ is the no. of clutch plates in a multi-plate clutch, then, number of pairs of contact surfaces = ‘n-1’. Therefore no. clutches plates = 7 – 1 = 6.
2. External diameter of the clutch facing is limited to 120 mm and the inner diameter may be assumed to be 0.3 times the external diameter. Assume uniform wear theory. What is the effective mean radius?
a) 68
b) 58
c) 98
d) 78
Answer: d
Explanation: External diameter = 120 mm. Given Internal diameter = 0.3*external diameter = 0.3 * 120 = 36 mm. Effective mean diameter = / 2 = 78 mm ⇒ Effective mean radius = 39 mm.
3. The clutch plate has 160 mm inside and 240 mm outside diameter. The total force provided by the springs is 5 kN, when the clutch is new. The coefficient of friction is 0.4. What is the torque transmitted?
a) 300 Nm
b) 350 Nm
c) 400 Nm
d) 450 Nm
Answer: c
Explanation: inside radius = 80 mm, outside radius = 120 mm ⇒ Effective mean radius = R = / 2 = 100 mm. Let W = 5 kN = 5000 N and μ = coefficient of friction = 0.4. Torque transmitted = 2 * μ * W * R = 2 * 0.4 * 5000 * 100 = 400 * 10 3 Nmm = 400 Nm.
4. Which of the following contains no linkage between the clutch and the pedal?
a) Clutch – by – wire
b) Wet clutch
c) Hydraulic single plate clutch
d) Hydraulic multi-plate clutch
Answer: a
Explanation: In clutch – by – wire system, there is no mechanical linkage between the clutch and the pedal. The ECU and the actuator control the clutch pedal.
5. Where is the clutch located?
a) Between transmission and engine
b) Between transmission and rear axle
c) Between transmission and propeller shaft
d) Between transmission and differential
Answer: a
Explanation: The clutch is in the middle of transmission and engine. So that torque can be transmitted from engine to the transmission whenever required.
6. Which of the following parts of the cover assembly that hold the pressure plate against the clutch plate?
a) Springs
b) Thrust bearings
c) Struts
d) Lever
Answer: a
Explanation: Springs hold the pressure plate against the clutch plate so that pressure can be exerted against the clutch plate and better power transmission can be obtained.
7. Which of the following is the coefficient of friction of the clutch plate?
a) 1.3
b) 0.8
c) 0.4
d) 0.1
Answer: c
Explanation: The coefficient of friction is always less than 1. Most commonly used material for the clutch plate is ceramic in case of racing cars, heavy loads, etc.
8. Which of the following is the disadvantage of the cone clutch?
a) It becomes difficult to disengage the clutch when the cone angle is less than 20°
b) It is silent in operation
c) The normal force on the contact surface is larger than the axial force
d) Same torque can be transmitted for the same size as the plate clutch
Answer: a
Explanation: When the cone angle of the cone clutch is less than 20° than the male part of the clutch join the female part and it difficult to disengage the clutch.
9. The external radius of the cone clutch is 120 mm and the internal radius is 80 mm. The cone angle is kept at 20°. What is the effective mean radius assuming the uniform wear theory?
a) 292 mm
b) 295 mm
c) 100 mm
d) 150 mm
Answer: a
Explanation: r i = 80 mm, r 0 = 120 mm and θ = 20°. Effective mean radius = (r i + r o ) / ) = / ) = 292.3 mm.
10. The dry clutch can tolerate longer engagement time than a wet clutch.
a) True
b) False
Answer: b
Explanation: Since metal to oil heat transfer is more effective than the metal to the air, the wet clutch acts as a much better heat exchanger and wet clutch can tolerate longer engagement time.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Transmission System – Gear Box”.
1. Which of the following is the need of the gearbox?
a) To vary the speed of the vehicle
b) To vary the torque of the vehicle
c) To vary the power of the vehicle
d) To vary the acceleration of the vehicle
Answer: b
Explanation: The purpose of the gearbox is to give means so that the torque can be varied as required between the engine and the road wheels.
2. In which type of manual transmission the double-declutching is used?
a) Constant-mesh gearbox
b) Sliding mesh gearbox
c) Synchromesh gearbox
d) Epicyclical gearbox
Answer: a
Explanation: The double-declutching is used in the constant-mesh gearbox. For the smooth engagement of the dog clutch, the speed of the main shaft and layshaft should be the same.
3. In which of the gearbox all gears are always in contact?
a) Constant-mesh gearbox
b) Sliding mesh gearbox
c) Synchromesh gearbox
d) Epicyclical gearbox
Answer: a
Explanation: In constant mesh gearbox, all gears on the layshaft and main shaft are in contact all the time. For selecting gear, the dog clutch is used.
4. In which of the gearbox sun and planet gear set is used?
a) Constant-mesh gearbox
b) Sliding mesh gearbox
c) Synchromesh gearbox
d) Epicyclical gearbox
Answer: d
Explanation: In epicyclic gearbox, the sun and planet gears are used. Using this arrangement various gear ratios can be obtained. Also, this type of gearbox is compact in design than other types of gearbox.
5. Where is the overdrive located?
a) Between transmission and engine
b) Between transmission and rear axle
c) Between transmission and propeller shaft
d) Between transmission and differential
Answer: c
Explanation: The overdrive is used to increase the gear ratio of the vehicle. It used where the high speed is needed at relatively low engine speed. By using overdrive, the wear of the engine parts is less and decreases the vibration and noise.
6. Which of the following is not part of automatic transmission?
a) Epicyclic gearbox
b) Torque convertor
c) Multi-plate clutch
d) Sliding mesh gearbox
Answer: d
Explanation: The automatic transmission consists of the epicyclic gearbox, torque convertor, and multi-plate clutch. The sliding mesh gearbox is a type of manual transmission.
7. In which of the configuration of epicyclic gearbox output will be forward and fast output speed?
a) Sun gear stationary, ring gear driven, planet carrier driving
b) Sun gear driving, ring gear driven, planet carrier stationary
c) Sun gear driven, ring gear stationary, planet carrier driving
d) Sun gear stationary, ring gear stationary, planet carrier driving
Answer: a
Explanation: When the Sun gear is stationary, the planet carrier is driving and the ring gear is driven then output is forward and fast speed. When any two of the three are stationary then we get the direct drive.
8. Which types of gears are used in constant mesh gearbox?
a) Spur gear
b) Helical gear
c) Bevel gear
d) Worm gear
Answer: b
Explanation: As the gears are always in mesh in the constant-mesh gearbox, therefore there is no need for using the spur gears and the helical gears are used as those are quite in use.
9. Why are the helical gears used commonly in transmission over spur gears?
a) Low cost and high strength
b) Low noise level and high strength
c) Low noise level and economy
d) Low noise level and low cost
Answer: b
Explanation: The teeth profile on the helical gear is at an angle to the axis of the gear because of which helical gears produce less noise during operation and also they have high strength.
10. Increase of torque in a vehicle is obtained by decreasing power.
a) True
b) False
Answer: b
Explanation: Increase of torque in a vehicle is obtained by decreasing speed. As we know P = 2πNT/60 for the same power , T is inversely proportional to N .
This set of Basic Automobile Engineering Questions and Answers focuses on “Universal Joints and Differential”.
1. Which types of joints are used when the shafts are inclined?
a) Universal joint
b) Hinge joint
c) Ball and socket joint
d) Pivot joint
Answer: a
Explanation: Universal joint is used when the shafts are inclined and intersecting. It is very compact in design and simple in construction. It is very effective at small angles of propeller shaft movement.
2. The axes of the two shafts are intersecting and are at 25° to each other. These two shafts are connected by Hook’s joint. At which position of the drives shaft velocity ratio will be maximum?
a) 90°, 270°
b) 0°, 180°
c) 180°, 270°
d) 90°, 180°
Answer: b
Explanation: (ω B / ω A ) = / (1 – cos 2 θ sin 2 α) where A = driving shaft and B = driven shaft and α is the angle between shaft A and shaft B. θ is the angle through which the shaft A rotates. Velocity ratio is maximum when θ = nπ where n = 1, 2, 3, …… i.e. θ = θ° or 180°.
3. Which of the following is the disadvantage of the open differential?
a) High in cost
b) Not reliable
c) Complex design
d) Sends most of the power to the wheel having less traction
Answer: d
Explanation: The major disadvantage of the open differential in that it transfers the power to the wheel even if it is on a slippery road. That’s why it is not used in off driving cars.
4. Why do the hypoid gears require special lubricant?
a) Teeth are soft
b) Teeth are hard
c) Gears run faster
d) There is relative motion between teeth
Answer: d
Explanation: Hypoid gears require special lubricant because of the extreme pressure between the teeth. The sliding motion of the teeth is effective due to the use of special lubricant.
5. The axes of the two shafts are intersecting and are at 30° to each other. These two shafts are connected by Hook’s joint. At which position of the drives shaft velocity ratio will be minimum?
a) 90°, 270°
b) 0°, 180°
c) 180°, 270°
d) 90°, 180°
Answer: a
Explanation: (ω B / ω A ) = / (1 – cos 2 θ sin 2 α) where A = driving shaft and B = driven shaft and α is the angle between shaft A and shaft B. θ is the angle through which the shaft A rotates. Velocity ratio is minimum when θ = m&pi/2 where m = 1, 3, 5, …… i.e. θ = 90° or 270°.
6. Where is the differential located?
a) Between transmission and rear axle
b) Between engine and transmission
c) Between two propeller shaft
d) Between steering wheel and steering column
Answer: a
Explanation: The differential used to incorporate the speed of the rear wheels and front wheels during turning. It is located between the transmission and rear axle.
7. The axes of the two shafts are intersecting and are at 35° to each other. These two shafts are connected by Hook’s joint. At which position of the drives shaft velocity ratio will not be unity?
a) 42.145°
b) 222.145°
c) 317.85°
d) 141.52°
Answer: d
Explanation: (ω B / ω A ) = / (1 – cos 2 θ sin 2 α) where A = driving shaft and B = driven shaft and α is the angle between shaft A and shaft B. θ is the angle through which the shaft A rotates. Velocity ratio is unity when tanθ = ± \(\sqrt{cos\alpha} = ± \sqrt{cos35}\) = ± 0.90 i.e. θ = 42.145°, 222.145°, 317.85°, and 137.85°.
8. What is the need of the universal joint?
a) To change inclination
b) To bend sideways
c) To transfer torque at an angle
d) To change length
Answer: c
Explanation: The universal joint transfers the torque to two intersecting shafts. One or two universal joints are used depending upon the type of rear-drive used.
9. The axes of the two shafts are intersecting and are at 35° to each other. These two shafts are connected by Hook’s joint. At which position of the drives shaft acceleration will be maximum?
a) 68.4°
b) 96.1°
c) 225.5°
d) 330.7°
Answer: c
Explanation: (ω B / ω A ) = / (1 – cos 2 θ sin 2 α) where A = driving shaft and B = driven shaft and α is the angle between shaft A and shaft B. θ is the angle through which the shaft A rotates. Acceleration will be maximum when cos2θ = (2 sin 2 α) / (2 – sin 2 α) =(2 sin 2 40°) / (2 – sin 2 40°) = 0.5207 i.e. 2θ = 58.62 i.e. θ = 29.31°, 180° – 29.31° = 150.69°, 180° + 29.31° = 209.31°, 360° – 29.31° = 330.69°
10. A two-piece propeller shaft requires one universal joint.
a) True
b) False
Answer: b
Explanation: A two-piece propeller shaft requires a center support bearing. If there is a large wheelbase, the long propeller shaft is needed. So a two-piece propeller shaft is used in such case with a center support bearing. By incorporating this there is no sag or whirl.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Steering System”.
1. The front axle of a car has pivot centers 1.3 m apart. The angle of inside lock is 40℃ and the angle of the outside lock is 35℃. What is the wheelbase of the car?
a) 5.5 m
b) 3.5 m
c) 4.5 m
d) 6.5
Answer: a
Explanation: For correct steering, cot α – cot θ = c / b where c = pivot center, b = wheelbase, α = angle of outside lock, and θ = angle of inside lock. Cot α – Cot θ = c / b ⇒ Cot 35 – Cot 40 = 1.3 / b ⇒ b = 5.49 m.
2. If the wheelbase, the pivot center, and wheel track of the are 2.5 m, 1.1 m, and 1.3 m respectively. The angle of the inside lock is 42℃. What is the circle radius of the outer front wheel?
a) 2.6 m
b) 3.6 m
c) 4.6 m
d) 1.6 m
Answer: b
Explanation: b = wheelbase = 2.5 m, c = pivot center = 1.1 m, a = wheel track = 1.3 m, and θ = angle of inside lock = 42℃. For the inner front wheel, radius =\(\frac{b}{sin\theta} – \frac{a – c}{2} = \frac{2.5}{sin42} – \frac{1.3 – 1.1}{2}\) = 3.6 m
3. What is the angle between the steering axis and the vertical in the plane of the wheel?
a) Castor
b) Camber
c) Steering axis inclination
d) Kingpin inclination
Answer: a
Explanation: Castor is the angle between the steering axis and the vertical in the plane of the wheel. Positive castor improves the straight-line stability of the car.
4. If the front of the front wheels is inside and rear of front wheels are apart when the vehicle is at rest, then the configuration is called?
a) Toe-in
b) Toe out
c) Positive camber
d) Positive castor
Answer: a
Explanation: Toe-in is the amount by which the front wheels are set closer together at the front than at the rear when the vehicle is stationary. Toe-in provided generally less than 3 mm.
5. What is the name of the angle through which the wheel has to turn to sustain the side force?
a) Slip angle
b) Castor angle
c) Camber
d) Kingpin inclination
Answer: a
Explanation: The slip angle is the angle through which the wheel has to be turned to sustain the side force on the wheel. The force produced due to this which counters the side thrust is known as cornering force.
6. What is called the cornering force over the slip angle?
a) Castor trail
b) Cornering power
c) Self-righting torque
d) Pneumatic trail
Answer: b
Explanation: The ratio of cornering force to the slip angle is called the cornering power. The cornering power increases due to tire stiffness.
7. What is a condition called when the vehicle will try to move away from its normal direction and to keep it on the right path there is need to steer a little?
a) Understeer
b) Oversteer
c) Reversibility
d) Irreversibility
Answer: a
Explanation: When the slip angles of the front wheels are greater than those for the rear wheels, the radius of the turn is increased. Due to which there is the need to steer more than required which is called understeer.
8. What is the purpose of the reciprocating ball type steering gear?
a) To reduce the operating cost
b) To reduce the number of parts
c) To reduce the operating friction
d) To reduce the toe-out during the turns
Answer: c
Explanation: The reciprocating ball type steering gear serve the purpose of reducing the friction and wear of the gear.
9. What is the angle between the vertical when the top of the wheel slants outward?
a) Negative camber
b) Negative castor
c) Positive camber
d) Positive castor
Answer: c
Explanation: The angle between the vertical when the top of the wheel slants outward is called positive camber. Positive camber will lead to decrease in turning radius and thus lead to a decrease in the steering effort.
10. The furniture rollers are provided with negative castor.
a) True
b) False
Answer: b
Explanation: The furniture rollers are provided with positive castor. The positive castor gives more directional stability. In positive castor, steering axis would meet the ground ahead of the center of the roller. The later wheel would always follow the former wheel.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Braking System”.
1. In a disc brake, which component provides the pad-to-disc adjustment?
a) Bleed screw
b) Piston
c) Caliper
d) Piston seal
Answer: d
Explanation: Piston seal provides the pad-to-disc adjustment in a disc brake. When the brake is applied, the piston seal deforms.
2. What is the braking torque at leading shoe if resultant frictional force acts at a distance of 250 mm from the brake drum center, coefficient of friction between the shoe and the drum as 0.5, the free ends of the two shoes are pushed apart with a force of 300 N which is acting at a distance of 320 mm from anchor, and two shoes are anchored together 170 mm away from the brake drum center?
a) 276.6 Nm
b) 256.6 Nm
c) 266.6 Nm
d) 246.6 Nm
Answer: c
Explanation: T L =\(\frac{W * L * \mu * R}{M-} = \frac{320 * 300 * 0.5 * 250}{170-}\) = 266666.66 Nmm = 266.6 Nm where L is the distance at which the force acts from the anchor, W is the force from the anchor, μ is the coefficient of friction, R is the distance of resulting friction force from brake drum center, M is the distance between the two anchors.
3. On what principle does the braking system in the car work?
a) Frictional force
b) Gravitational force
c) Magnetic force
d) Electric force
Answer: a
Explanation: Frictional force is the main force which acts and plays an important role in the braking system. The disc pads get to rub against the drum and which creates the friction and opposes the motion of the rotational motion of the drum.
4. Generally which brakes are on the front wheels?
a) Drum brake
b) Disk brake
c) Shoe brake
d) Double shoe brake
Answer: b
Explanation: Disk brakes are used usually on the front wheels. When the brakes are applied the 70% of the weight is transferred to the front wheels. Because of which the brakes on the front wear out faster.
5. If the car is moving on the level road at a speed of 50 km/h has a wheelbase 3 m, a distance of C.G. from ground 700 mm and distance from rear wheels is 1.1 m. Coefficient of friction is 0.7. What is the retardation if the brakes are applied to the rear wheels?
a) 3.7 m/s 2
b) 2.7 m/s 2
c) 1.7 m/s 2
d) 4.7 m/s 2
Answer: a
Explanation: When the brakes are applied on the rear wheels and the vehicle is moving on the level road, a = \(\frac{\mu * g * }{L+μ * h}\) where ‘μ’ is the coefficient of friction, ‘L’ is wheelbase, ‘x’ is a distance of C.G. from rear wheels, and ‘h’ is the distance of the C.G. from the surface of the road. Therefore a = \(\frac{0.7 * 9.81 * }{3+}\) = 3.7 m/s 2 .
6. If the car is moving on the level road at a speed of 50 km/h has a wheelbase 4 m, a distance of C.G. from ground 800 mm and distance from rear wheels is 1.2 m. Coefficient of friction is 0.8. What is the retardation if the brakes are applied to the front wheels?
a) 3.4 m/s 2
b) 2.4 m/s 2
c) 1.4 m/s 2
d) 4.4 m/s 2
Answer: b
Explanation: When the brakes are applied on the front wheels and the vehicle is moving on the level road, a = \(\frac{\mu * g * x}{L-\mu* h}\) where ‘μ’ is the coefficient of friction, ‘L’ is wheelbase, ‘x’ is a distance of C.G. from rear wheels, and ‘h’ is the distance of the C.G. from the surface of the road. Therefore a = \(\frac{0.7 * 9.81 * 1.2}{4-}\) = 2.4 m/s 2 .
7. If the car is moving on the level road at a speed of 50 km/h has a wheelbase 4 m, a distance of C.G. from ground 800 mm and distance from rear wheels is 1.2 m. Coefficient of friction is 0.8. What is the retardation if the brakes are applied to all wheels?
a) 7.8 m/s 2
b) 6.8 m/s 2
c) 5.8 m/s 2
d) 4.8 m/s 2
Answer: a
Explanation: When the brakes are applied on all wheels and the vehicle is moving on the level road, a = μ*g where ‘μ’ is the coefficient of friction, ‘L’ is wheelbase, ‘x’ is a distance of C.G. from rear wheels, and ‘h’ is the distance of the C.G. from the surface of the road. Therefore a = 0.8 * 9.81 = 7.8 m/s 2 .
8. The car is moving up on the 12o inclined road with horizontal at 36 km/h which is having wheelbase 1.4 m. The C.G. of the car is 0.9 m above the road. The coefficient of friction is 0.7. What is the retardation of the car if the brakes are applied to all the four wheels?
a) 8.75 m/s 2
b) 8.81 m/s 2
c) 7.71 m/s 2
d) 6.81 m/s 2
Answer: a
Explanation: α is the inclination angle in degree = 12°, μ is the coefficient of friction = 0.7. When the vehicle is moving up on the inclined road and brakes are applied to all four wheels than the retardation a = g* = 9.81* = 8.75 m/s 2 .
9. The car is moving down on the 14° inclined road with horizontal at 36 km/h which is having wheelbase 1.4 m. The C.G. of the car is 0.9 m above the road. The coefficient of friction is 0.75. What is the retardation of the car if the brakes are applied to all the four wheels?
a) 4.76 m/s 2
b) 5.76 m/s 2
c) 6.76 m/s 2
d) 7.76 m/s 2
Answer: a
Explanation: α is the inclination angle in degree = 14° μ is the coefficient of friction = 0.75. When the vehicle is moving down on the inclined road and brakes are applied to all four wheels than the retardation a = g* = 9.81* = 4.76 m/s 2 .
10. The metering valve is used to proportion the braking effect between the front and the rear axle.
a) True
b) False
Answer: b
Explanation: The proportioning valve is used to proportion the braking effect between the front and the rear axle.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Ignition System”.
1. Which instrument is used for adjusting the ignition timing?
a) Accurate clock
b) Tachometer
c) Stopwatch
d) Stroboscopic light
Answer: d
Explanation: Stroboscope is used for adjusting the ignition timing. It is the light-emitting device which is connected to the spark plug of the cylinder for setting the ignition timing.
2. Which of the following firing order is commonly used for the four-cylinder vertical engine?
a) 1-2-3-4
b) 3-4-1-2
c) 4-3-2-1
d) 1-3-4-2
Answer: d
Explanation: 1-3-4-2 firing order is commonly used for a four-cylinder engine. For the four-cylinder engine, the firing order is decided such that a power stroke occurs every 180 degrees.
3. What is the dwell time?
a) It is the time for which the contact breaker points remain closed
b) It is the time for which the contact breaker points remain open
c) The time during which inlet and exhaust valves open
d) The time during which inlet and exhaust valves close
Answer: a
Explanation: The dwell time is the time for which the contact breaker points remain closed. Dwell is the time for which the coil turned on.
4. Which of the following is not considered while deciding the optimum firing order of the engine?
a) Engine vibration
b) Engine cooling
c) Development of the backpressure
d) Engine configuration
Answer: d
Explanation: Engine vibration, engine cooling, and development of back pressure are considered while deciding the optimum firing order of the engine. The reduced vibration is required for optimum firing order of the engine.
5. Why is the Dwell meter used?
a) To set the spark plug gap
b) To set the ignition advance
c) To set the contact breaker gap
d) To set ignition timing
Answer: c
Explanation: The dwell meter used for setting the contact breaker gap. It uses the dwell angle as the parameter to set the contact breaker gap. To set the ignition timing stroboscope is used.
6. Which of the following is the disadvantage of the magneto ignition system?
a) Magneto ignition system has a poor quality of spark during starting
b) Magneto ignition system occupies more space
c) Magneto ignition system has more maintenance problems
d) Magneto ignition system is used largely in four wheels
Answer: a
Explanation: During starting, the quality of the spark is poor due to low speed. Magneto ignition system is mainly used in racing cars and two-wheelers. The main advantage is that it does not require a battery.
7. For how many times the contact breaker must make and break the circuit for a four-cylinder engine operating at N rpm?
a) N times
b) 1.5N times
c) N/2 times
d) 2N times
Answer: d
Explanation: The cam is having the same number of lobes as there are engine cylinders. They are used with two contact breakers in parallel.
8. Which of the following is the wrong statement?
a) In the exhaust, retarded timing causes burning of the hydrocarbons
b) The retarded timing improves fuel economy
c) The retarded timing requires the small opening for correct burning of the fuel
d) The exhaust gas temperature becomes higher due to retarded time
Answer: b
Explanation: The retarded timing reduces fuel economy. Due to spark retardation, the fuel burns slowly and after some time than it should be burned.
9. On which condition does the vacuum advance mechanism shift the ignition point?
a) Under part-load operation
b) Under full load operation
c) Under no-load operation
d) Under sudden acceleration
Answer: a
Explanation: The vacuum advance mechanism shifts the ignition point under part-load operation. The adjustment system is designed so that its operation results in the part-load advance curve.
10. The optimum spark timing must be retarded for the engine operating with a rich mixture.
a) True
b) False
Answer: b
Explanation: The optimum spark timing must be advanced for the engine operating with a rich mixture. The larger throttle opening size means better mixing and combustion.
This set of Automobile Engineering Problems focuses on “Alternative Fuels for IC Engines”.
1. Which of the following statements is not correct with respect to alcohols as alternate fuel?
a) Anti-knock characteristics of alcohol are poor
b) Alcohol contains about half the heat energy of gasoline/liter
c) Alcohol does not vaporize as easily as gasoline
d) Alcohols are corrosive in nature
Answer: a
Explanation: Alcohol is a high octane fuel. It has an anti-knock index number of over 100. The engines which use the high octane fuel run more efficiently by using higher compression ratios.
2. Why a small amount of gasoline is added to alcohol?
a) To reduce the emission
b) To increase the power output
c) To increase the power efficiency
d) To improve cold-weather starting
Answer: d
Explanation: When a small amount of gasoline is added to alcohol, it improves cold-weather starting. Alcohols have low energy content. This means that almost twice as much alcohol as gasoline must be burned to give the same energy input.
3. What is gasohol?
a) 90% ethanol + 10% gasoline
b) 10% ethanol + 90% gasoline
c) 40% ethanol + 60% gasoline
d) 50% ethanol + 50% gasoline
Answer: b
Explanation: Gasohol is 10% ethanol and 90% gasoline. Gasohol is also known for E10. E10 reduces the use of gasoline with no modification needed to the automobile engine. E10 is basically an alcohol fuel with 90% gasoline added to eliminate some of the problems of pure alcohol.
4. Which of the following is a disadvantage of hydrogen as a fuel in IC engine?
a) Storage is easy
b) Low NO x emissions
c) Detonating tendency
d) Easy handling
Answer: c
Explanation: The disadvantage of hydrogen fuel is that the detonating tendency. The other disadvantages of hydrogen fuel are high NO x emissions because of high flame temperature and difficult to refuel.
5. Which of the following is the advantage of the hydrogen as a fuel?
a) High volumetric efficiency
b) Low fuel cost
c) No HC and CO emissions
d) Relatively safe
Answer: c
Explanation: The advantage of hydrogen fuel is no hydrocarbon and CO emissions. The most exhaust gases would be H 2 O and N 2 and NO x .
6. What is the major disadvantage of LPG as a fuel in the automobile?
a) Reduction in the life of the engine
b) Less power compared to gasoline
c) Reduction in the life of the engine and less power compared to gasoline
d) Knocking tendency
Answer: c
Explanation: The major disadvantage of LPG is the reduction in the life of the engine and less power compared to gasoline. The other disadvantage of LPG is a special fuel feed system is required for liquid petroleum gas .
7. Why alcohols cannot be used in CI engines?
a) Alcohols have a high self-ignition temperature
b) The latent heat of vaporization is low
c) Alcohols have high self-ignition temperature and low latent heat of vaporization
d) High efficiency
Answer: c
Explanation: Alcohols have high self-ignition temperature and low latent heat of vaporization. That is why they cannot be used in CI engines.
8. Which of the following is the major constituent of natural gas?
a) Methane
b) Ethane
c) Butane
d) Propane
Answer: a
Explanation: Methane is the major constituent of natural gas. The composition varies from place to place and from time to time. Natural gas is a mixture of components, consisting, mainly of methane with small amounts of other hydrocarbon fuel components.
9. Why methanol is not used in CI engine?
a) Its octane number is high
b) Its cetane number is low
c) Its octane number is high and the cetane number is low
d) Its octane number is low and the cetane number is high
Answer: c
Explanation: Methanol is not used in CI engines because of its high octane number and low cetane number. Pure methanol and gasoline in various percentages have been extensively tested in engines and vehicles for a number of years.
10. What is octane number of natural gas?
a) 60-80
b) 80-100
c) >100
d) <60
Answer: b
Explanation: The octane number of natural gas ranges between 80 and 100, due to which it is used as SI engine fuel. The advantages of natural gas are low engine emissions.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Engine Emissions”.
1. Which of the following is one of the major exhaust emissions from CI engines compared to SI engines?
a) Oxides of nitrogen
b) Particulates
c) CO and CO 2
d) Unburnt hydrocarbon
Answer: b
Explanation: Unburnt hydrocarbons are one of the major exhaust emissions from CI engines. The components in diesel fuel have higher molecular weight.
2. Which of the following causes the photochemical smog?
a) Excess O 2
b) CO and CO 2
c) Soot and particulate matter
d) NO x and HC
Answer: d
Explanation: NO x is one of the primary causes of photochemical smog. This smog is formed by the photochemical reaction of automobile exhaust and atmospheric air in the presence of sunlight.
3. What does the blue smoke in diesel engine indicate?
a) Unburnt oil
b) HC
c) NO x
d) CO
Answer: a
Explanation: Blue smoke comes out from the exhaust when there is unburnt oil in the diesel engine. A very thin layer of the oil gets deposited on the cylinder wall to provide the lubrication between the walls and the moving piston.
4. During which condition of the vehicle does NO x emission in SI engine will be lowest?
a) Cruising
b) Idling
c) Accelerating
d) Decelerating
Answer: b
Explanation: NO x emissions are lowest in SI engine during idling. NO x is created from nitrogen in the air. Nitrogen can also be found in fuel blends.
5. For what purpose is the Rhodium used?
a) To reduce CO and HC
b) To reduce NO x
c) To reduce CO
d) To reduce HC
Answer: b
Explanation: Rhodium is used to reduce NO x . It is used to clean vehicle emission. It is mixed with the other two metals – platinum and palladium.
6. Why is the fumigation technique used?
a) To control HC
b) To control NO x
c) To control CO
d) To control smoke
Answer: d
Explanation: The fumigation technique is used to control smoke. Fumigation is injecting gaseous or liquid fuel into the intake of air steam of CI engines. There are two types of smoke: hot smoke and cold smoke.
7. Why are lead compounds added in petrol?
a) Reduce knocking
b) Reduce HC emission
c) Reduce exhaust temperature
d) Increase power output
Answer: b
Explanation: The lead compounds are added in petrol to reduce the HC emission. The additive TEL was added to increase the octane number. The resulting lead in the engine exhaust was a poisonous pollutant.
8. Which of the following cannot be reduced by thermal converters?
a) CO
b) HC
c) Soot
d) NO x
Answer: d
Explanation: NO x emission cannot be reduced using a thermal converter. Thermal converters are high-temperature chambers through which the exhaust gas flows.
9. What can be reduced by using exhaust gas recirculation effectively?
a) CO
b) NO x
c) HC
d) CO and HC
Answer: b
Explanation: The most effective way of reducing NO x emission is to hold combustion chamber temperatures down. Using this also reduces the thermal efficiency of the engine.
10. Three-way catalytic converters reduce the emission of CO, HC, and soot.
a) True
b) False
Answer: b
Explanation: Three-way catalytic converters reduce the emission of CO, NO x , and HC. They are chambers contain catalytic material. It promotes the oxidation of the emission contained in the exhaust flow.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Vehicles and Powertrain”.
1. What is running resistance of the vehicle?
a) Rolling resistance
b) Aerodynamic resistance
c) Sum of rolling and aerodynamic resistance
d) Traction force
Answer: c
Explanation: Running resistance is the sum of rolling and aerodynamic resistance. F running = F rolling + F aerodynamic = (μ k * m vehicle * g) + (0.5 * ρ * C drag * A front * V 2 ). It is the resistance that will affect when the vehicle is running. Running resistance is directly proportional to the mass of the vehicle, frontal area, and velocity. Increasing any of the above parameters will increase running resistance. Tractive force is the effort from the powertrain. Rolling resistance is the frictional resistance that wheels have to overcome. Aerodynamic resistance is the drag force acting against the motion of the vehicle.
2. Suppose the road gradient is G = 10%. What is the corresponding angle ?
a) 5 rad
b) 0.1 rad
c) 1 rad
d) 10 rad
Answer: b
Explanation: G = tan . For small angles α, tan = α. Hence α = 10% = 0.1 rad. The corresponding angle for road gradient G = 10% is 0.1 rad.
3. If the vehicle mass is 800 kg, what is the gradient force caused by the road gradient 10%?
a) 500 N
b) 600 N
c) 700 N
d) 800 N
Answer: d
Explanation: F gradient = m vehicle * g * sin . For small angle, sin = α. Hence, α = 10% = 0.1 rad. Taking g = 10 m/s 2 , F gradient = 800*10*0.1 = 800 N.
4. What will happen if the traction force is negative?
a) The vehicle will accelerate
b) The vehicle will decelerate
c) The vehicle will first accelerate and then decelerate
d) The vehicle will run at a constant speed
Answer: b
Explanation: F net = m vehicle * a vehicle = F traction – F rolling – F aerodynamic . If the F traction is negative, then F net will be more negative ⇒ a vehicle is negative. Therefore the vehicle will decelerate.
5. Suppose the vehicle is running at a constant speed on the flat road with rolling resistance = 100 N and aerodynamic resistance = 100 N, what is the traction force required?
a) 100 N
b) 0 N
c) 200 N
d) 50 N
Answer: c
Explanation: F net = F traction – F rolling – F aerodynamic – F gradient = 0 N . Flat road ⇒ F gradient = 0. Hence F traction = F rolling + F aerodynamic + F gradient = 100 + 100 + 0 = 200 N.
6. Which one of the curves below represents a road gradient of 10%, if the mass of the vehicle is 1 ton?
automobile-engineering-questions-answers-vehicles-powertrain-q6
a) B
b) A
c) D
d) C
Answer: a
Explanation: F gradient = m vehicle * g * sin . For small angles α, sin = α = G. At G = 10%, sin = 0.1 = α. Hence F gradient = 1000 * 9.81 * 0.1 = 981 N. Using G = 0% curve as base curve and at speed = 0 Kmph, curve B is higher than the G = 0% curve across the full speed range.
7. What will happen if the vehicle is made 50% heavier, but all other parameters remain the same?
a) The running resistance will decrease
b) The running resistance will increase
c) The running resistance will remain the same
d) The aerodynamic resistance will increase by a factor of 1.5 squared
Answer: b
Explanation: F running = F rolling + F aerodynamic = (μ k * m vehicle * g) + (0.5 * ρ * C drag * A front * V 2 ). The running resistance is the sum of rolling and aerodynamic resistance. Running resistance is directly proportional to the mass of the vehicle. As the mass of vehicle increases rolling resistance increases and thus, the running resistance increases. The aerodynamic resistance is independent of the vehicle mass.
8. If F rolling = 150 N, F aerodynamic = 400 N, F traction = 600 N, F gradient = 0 N, what is the net force acting on the vehicle?
a) 100 N
b) 50 N
c) 550 N
d) 750 N
Answer: b
Explanation: F net = F traction – F rolling – F aerodynamic – F gradient = 600 – 150 – 400 – 0 = 50 N.
9. If the traction resistance is equal to the total running resistance, then which of the following will happen?
a) The vehicle will accelerate
b) The vehicle will decelerate
c) The vehicle will run at a constant velocity
d) The vehicle will come to rest
Answer: c
Explanation: F traction = F running . F running = F rolling + F aerodynamic and F net = F traction – (F rolling + F aerodynamic ). F net = F traction – F running = 0 N = m vehicle * a vehicle ⇒ a vehicle = 0 ⇒ V vehicle = constant. Therefore the vehicle will run at a constant velocity.
10. If the vehicle is running on the road having 10% gradient at a constant speed, then on flat road it will accelerate at approximately 1 m/s2 .
a) True
b) False
Answer: a
Explanation: F net = F traction – F rolling – F aerodynamic – F gradient . In case 1: Due to constant speed ⇒ a vehicle = 0 ⇒ F net = 0 N and F traction = F rolling + F aerodynamic + F gradient . In case 2: Due to flat road, F gradient = 0 N and F net = F traction – F rolling – F aerodynamic . As all parameter remain the same ⇒ F traction will be the same. Therefore F net = F gradient . F net = m vehicle * a vehicle = m vehicle * g * sin = F grad . For small values, sin = α. Therefore a vehicle = g * α = 9.81 * 0.1 = 0.981 m/s 2 which is approximately 1 m/s 2 .
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Engine Electronics”.
1. Which of the following is the knock sensor?
a) Flap type sensor
b) Thermocouples
c) Thermistors
d) Piezoelectric pickup
Answer: d
Explanation: Piezoelectric pickup is the knock sensor. This sensor is mounted on the cylinder block. Knock sensor system uses a sensor, which is piezoelectric vibration pickup.
2. What is the use of the lambda sensors in the catalytic converter?
a) To keep excess air ratio within a range
b) To keep the flow rate of constant air
c) To keep the exhaust pressure constant
d) To keep the exhaust temperature constant
Answer: a
Explanation: In catalytic convertor, the lambda sensors are used to keep excess air ratio within a range. The catalytic converter is the emission control device.
3. Where are the electro-optical sensors used?
a) Position and speed measurement
b) Piston temperature measurement
c) Cooling water flow measurement
d) Lubricating oil flow measurement
Answer: a
Explanation: The electro-optical sensors can be used for position and speed measurement. These devices can operate on high frequencies. Also, it can detect fast-moving objects.
4. What is the main use of the strain gauge?
a) To measure viscosity
b) To measure velocity
c) To measure temperature
d) To measure pressure
Answer: d
Explanation: The main use of the strain gauge is to measure pressure. In this sensor, the conductor changes the dimension along with the member whose strain is to be measured.
5. What is the use of the hot-wire sensor?
a) To measure temperature
b) To measure the smoke intensity
c) To measure the mass flow rate
d) To measure pressure
Answer: c
Explanation: The hot-wire sensor is used to measure the mass flow rate. This sensor is positioned between the air filter and the throttle valve.
6. What is the disadvantage of the piezoelectric pressure sensor?
a) It has too much sensitivity
b) It can measure only low pressure
c) It is not suitable for dynamic measurement
d) It can only give pressure difference
Answer: d
Explanation: The disadvantage of the piezoelectric pressure sensor is that it can only give the pressure difference. The advantages of the piezoelectric pressure sensor are quick frequency response and they are of small size.
7. What is LVDT used to measure?
a) Gas temperature
b) Engine speed
c) Crank angle
d) Large displacement
Answer: d
Explanation: LVDT is used to measure the large displacement. These are only used for the low-frequency measurements. These sensors are used to measure the parameters like valve lift etc.
8. In which of the following See beck effect is used?
a) Hot-wire sensors
b) Resistance temperature detectors
c) Thermocouples
d) Thermistors
Answer: c
Explanation: Thermocouples use the Seebeck effect to measure the temperature. Thermocouples can be used for high-temperature measurement.
9. Which of the following is used by the Hall Effect pickup?
a) Thermistors
b) Potentiometers
c) Inductive transducers
d) Semiconductors
Answer: d
Explanation: In Hall Effect pickup, semiconductors are used. This sensor used for detecting the position of the shaft and speed. This sensor can be used to detect motion.
10. Vortex sensor is used for measurement of the temperature.
a) True
b) False
Answer: b
Explanation: Vortex sensor is used for measurement of the intake airflow. In this sensor, as the air passes the bluff body creates the vortex. Due to which pressure disturbances are created which can be sensed by the microphone.
This set of Automobile Engineering Questions and Answers for Aptitude test focuses on “Performance Parameters and Characteristics”.
1. Which of the following is correct?
a) Thermal efficiency varies directly as specific fuel consumption
b) Thermal efficiency varies inversely as specific fuel consumption
c) Thermal efficiency varies as root as specific fuel consumption
d) Thermal efficiency varies as square as specific fuel consumption
Answer: b
Explanation: Specific fuel consumption is the ratio of fuel consumption rate to the power produced. Thermal efficiency is the ratio of the power produced to the fuel consumption rate. Hence both are inversely proportional to each other.
2. What is mechanical efficiency?
a) The ratio of friction power to brake power
b) The ratio of the brake power to indicated power
c) The ratio of indicated power to friction power
d) The ratio of friction power to indicated power
Answer: d
Explanation: Mechanical efficiency is the ratio of friction power to indicated power. Mechanical efficiency takes into account the mechanical losses. The mechanical losses are divided into friction losses; power absorbed, ventilating action, and work of charging the cylinder.
3. What is volumetric efficiency?
a) A measure of the power of the engine
b) A measure of the speed of the engine
c) A measure of pressure rise in the cylinder
d) A measure of breathing capacity of the engine
Answer: d
Explanation: Volumetric efficiency is the ratio of the displaced volume of the fluid by the piston to the swept volume. It is the ratio of actual mass of air drawn by the engine to the theoretical mass which should be drawn by the engine.
4. What does the Sankey diagram represent?
a) Torque vs speed
b) Heat balance of the engine
c) Air consumption vs speed
d) ηbth vs brake power
Answer: b
Explanation: Sankey diagram represents the heat balance sheet of the engine. In this diagram, the width of the stream represents the heat quantity being considered.
5. The Otto engine consumes 9 liters of petrol per hour and develops 30 kW. The specific gravity of petrol is 0.8 and its calorific value is 45000 kJ/kg. What is the indicated thermal efficiency of the engine?
a) 33.33%
b) 25%
c) 30%
d) 32%
Answer: d
Explanation: η ith = heat equivalent of indicated power / heat input = / (9*10 -3 *800)*45000 = 33.33%.
6. Which of the following relation between indicated mean effective pressure , brake mean effective pressure and friction mean effective power is correct?
a) imep = fmep + bmep
b) imep = fmep * bmep
c) imep = fmep – bmep
d) imep = fmep / bmep
Answer: a
Explanation: Indicated mean effective pressure considered to be consists of the brake mean effective pressure and the friction mean effective pressure .
7. The indicated power of the single-cylinder engine is 1.9 kW. It develops torque of 10 Nm at 1600 rpm. What is the friction power as the percentage of brake power?
a) 12.43%
b) 13.43%
c) 14.43%
d) 15.43%
Answer: b
Explanation: Brake power = bp, Indicated power = ip = 1.9kW, friction power = fp, speed = N = 1600 rpm, and torque = T = 10 Nm. Brake power = bp = 2πNT / 60000 = 2π * 1600 * 10 / 60000 = 1.675 kW. Friction power = fp = ip – bp = 1.9 – 1.675 = 0.225 kW. Percentage loss = *100 = *100 = 13.43%.
8. The bore and stroke of the single-cylinder four-stroke engine are 90 mm and 120 mm respectively. The torque is 24 Nm. What is the brake mean effective pressure of the engine?
a) 3.9 bar
b) 4.9 bar
c) 5.9 bar
d) 6.9 bar
Answer: a
Explanation: Brake mean effective pressure = p bm , torque = T = 24 Nm, stroke = L = 120 mm, bore = D = 90 mm. p bm = 16T / D 2 L = / = 3.9 * 10 5 Pa = 3.9 bar.
9. What is brake specific fuel consumption of engine whose fuel consumption if 6 grams per second and power output is 90 kW?
a) 0.24 kg/kWh
b) 0.0667 kg/kWh
c) 0.54 kg/kWh
d) 0.44 kg/kWh
Answer: a
Explanation: Brake specific fuel consumption = ṁ f / bp where bp = brake power and ṁ f = brake specific fuel consumption. Brake specific fuel consumption = 6 / 90 = 0.0667 g/kW-s = / 1000 = 0.24 kg/kWh.
10. If the ip =2.62 kW and bp = 2.4 kW than fp = 5.04 kW
a) True
b) False
Answer: b
Explanation: Friction power = fp, brake power = bp = 2.4 kW, and indicated power = ip = 2.62 kW. ip = bp + fp ⇒ fp = ip – bp = 2.62 – 2.4 = 0.22 kW.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Measurements and Testing”.
1. To which of the following Morse test is applicable?
a) Single-cylinder SI engines
b) Single-cylinder CI engines
c) Multi-cylinder CI engines
d) Single and multi-cylinder SI and CI engines
Answer: c
Explanation: The Morse test is used to measure the indicated power from multi-cylinder CI engines. The test consists of obtaining the indicated power of the CI engines without any apparatus.
2. For which of the following the Chemiluminescence analyzer is used to measure?
a) NO x
b) CO
c) HC
d) CO 2
Answer: a
Explanation: The Chemiluminescence analyzer is used to measure NO x in the exhaust gases from the engine. The principle of measurement is based on Chemiluminescence reaction between ozone and NO. It results in the formation of excited NO 2 .
3. Which of the following is the best method to measure the speed?
a) Mechanical tachometer
b) Electrical tachometer
c) Magnetic pickup
d) Mechanical counters
Answer: c
Explanation: Magnetic pickup is the best device to measure the speed. Mechanical and electrical tachometers are affected by temperature variation and those are not accurate.
4. Which of the following is the most accurate method of determining friction power?
a) Morse test
b) Willian’s line
c) Motoring test
d) Measurement of brake and indicated power
Answer: d
Explanation: The friction power can be obtained by measurement of the brake and indicated power. The indicated power can be obtained by indicated diagram and brake power obtained by a dynamometer.
5. What is the requirement of the air box in the airbox method of measuring airflow?
a) To dump out the pulsation
b) To provide the constant velocity of flow
c) To have a constant flow
d) To have a constant temperature
Answer: a
Explanation: The airbox is used to dump out the pulsation while measuring the airflow. In IC engines, the satisfactory measurement of the air consumption is difficult because the flow is pulsating due to the cyclic nature of the engine and because the air is a compressible fluid.
6. For which of the following the flame ionization detector is used to measure?
a) CO
b) HC
c) CO 2
d) NO x
Answer: b
Explanation: Flame ionization detector is used to measure the hydrocarbon concentration. Ionization is the characteristic of HC compound.
7. Which of the following is the most accurate dynamometer?
a) Eddy current dynamometer
b) Prony brake dynamometer
c) Hydraulic type dynamometer
d) Swinging field type dynamometer
Answer: d
Explanation: Swinging field type dynamometer is the most accurate dynamometer. It consists of an electrical machine which may be run either by motor or generator.
8. For which of the following the non-dispersive infra-red analyzer is used to measure?
a) CO 2
b) CO
c) HC
d) NO x
Answer: b
Explanation: Non-dispersive infra-red analyzer is used to measure CO. The method of detection is based on the principle of selective absorption of the infrared energy of particular wavelength unique to a certain gas which will be absorbed by that gas.
9. What can be obtained from the engine indicator diagram?
a) Indicated mean effective pressure
b) Brake mean effective pressure
c) Relative efficiency
d) Mechanical efficiency
Answer: a
Explanation: The engine indicator diagram is used to obtain the indicated mean effective pressure. Pressure-volume, P-V, and pressure-crank angle, P-θ is the two types of indicator diagram that can be obtained from an engine. Both these indicator diagrams are mutually convertible.
10. On which of the following does brake mean effective pressure in an engine depend upon?
a) Speed and torque
b) Speed and power
c) Torque
d) Speed
Answer: b
Explanation: Brake power = 2πNT / 60000 where N =engine speed in RPM and T = torque in Nm. The dynamometers give the engine torque from which the brake power can be calculated. Thus the brake mean effective pressure in an engine depends on torque only. Also, Brake power = P mb *L*A*n / 60000. Therefore, P mb = kT where k = 2π / L*A and k = 4π / L*A where L = stroke length, A = cross-sectional area of the cylinder, n = no. of working strokes per minute and, P mb = brake mean effective pressure.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Nonconventional Engines”.
1. What is a dual fuel engine?
a) The engine which uses gaseous and liquid fuel
b) The engine which uses two liquid fuels
c) The engine which uses two gaseous fuels
d) The engine which uses one liquid and any other fuel
Answer: a
Explanation: The duel fuel engine uses gaseous and liquid fuel. The dual-fuel engine works on the diesel cycle. The gaseous fuel is called the primary fuel. The mixture of air and gaseous fuel is compressed in the cylinder.
2. Which of the following has the same combustion as HCCI engine?
a) SI engine
b) CI engine
c) Hybrid of both SI and CI engine
d) Wankel engine
Answer: c
Explanation: HCCI engine has the same combustion as a hybrid of both SI and CI engine. HCCI is a form of IC engine in which well-mixed fuel and air are compressed to the auto-ignition temperature of the fuel.
3. Which of the following is true for the HCCI engine?
a) Emits high NO x and soot
b) Have a large power range
c) Efficiency is comparatively less
d) Pre-catalyst hydrocarbon emissions are higher
Answer: d
Explanation: Pre-catalyst hydrocarbon emissions are higher is one of the disadvantages of the HCCI engine. The advantages of the HCCI engine are NO x and soot emissions are almost negligible.
4. For which of the following engine lean-burn concept is ideal?
a) CI engine
b) SI engine
c) Free piston engine
d) Wankel engine
Answer: b
Explanation: SI engines are more ideal for the lean-burn concept. A lean-burn mode is a way to reduce throttling losses. In SI engine, the power is reduced by partially closing a throttle.
5. By which technique can the charge stratification be achieved?
a) Injection
b) Carburetion
c) Lean burn technology
d) Injection as well as carburation
Answer: d
Explanation: The charge stratification can be achieved by injection as well as carburation. Charge stratification means providing different fuel-air mixture strengths at various places in the combustion chamber.
6. Which of the following is true for stratified charge engine?
a) More prone for knock
b) Multi-fuel capabilities
c) More throttling losses
d) Overall rich mixture
Answer: b
Explanation: Multi-fuel capabilities are one of the advantages of the stratified charge engine. The stratified engines are developed to combine both advantages of diesel and petrol engines.
7. What is true about the Wankel engine?
a) It is a rotary external combustion engine
b) It is more expensive
c) It has a longer operating cycle
d) It has less time to complete the combustion
Answer: c
Explanation: Wankel engine is a type of internal combustion engine using rotary design to convert pressure into a rotating motion. It does not make use of reciprocating pistons.
8. Where is the variable compression ratio used?
a) SI engine
b) CI engine
c) Wankel engine
d) HCCI engine
Answer: a
Explanation: Variable compression is used in SI engines. There are several methods for changing both the geometric and effective compression ratio.
9. Which of the following is true for stratified charge engine?
a) More prone for knock
b) It uses an overall rich mixture
c) It has a lot of throttling losses
d) It has multi-fuel capabilities
Answer: d
Explanation: Stratified charge engine has multi-fuel capabilities. The advantages of a stratified charge engine are higher thermodynamic efficiency and reduced air pollution.
10. Which of the following is true about the Stirling engine?
a) High efficiency
b) Quiet operation
c) Compatible with alternative and renewable energy
d) High efficiency, quiet operation and compatible with renewable energy
Answer: d
Explanation: The Stirling engine has high efficiency. A Stirling engine is a heat engine operating on cyclic compression and expansion of air or any other fluid.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Storage Batteries”.
1. What is the colour of a positive plate of a lead-acid battery?
a) White
b) Grey
c) White
d) Brown
Answer: d
Explanation: A positive plate of a lead-acid battery is brown in colour. A negative plate of a lead-acid battery is grey in colour. For each plate, there is a supporting grid made of an alloy of lead and antimony.
2. What gets deposited on the plates of a discharged lead-acid battery?
a) PbO 2
b) Pb 2 O 4
c) Pb
d) PbSO 4
Answer: d
Explanation: PbSO 4 gets deposited on the plates of a discharged lead-acid battery. During discharging the reaction happens in the right direction. PbSO 4 gets deposited on both negative and positive plates.
3. What is the twenty-minute rating of battery?
a) Rate of current for 20 minutes with a minimum cell voltage of 1.5 V
b) Time for which the battery can supply 25 A at 80℉ with minimum cell voltage 1.75 V
c) The current which the battery can supply continuously for 30 seconds with minimum cell voltage 1.2 V
d) Lasting power of a battery on a small load
Answer: a
Explanation: The rate of current 20 minutes with a minimum cell voltage of 1.5 V is called a twenty-minute rating of the battery. The temperature of the battery at the start of the test is brought to 80℉. It represents the rate of current a battery can deliver continuously.
4. What is the reserve capacity of battery?
a) Time for which the battery can supply 25 A at 80℉ with minimum cell voltage 1.75 V
b) The current which the battery can supply continuously for 30 seconds with minimum cell voltage 1.2 V
c) Lasting power of a battery on a small load
d) Rate of current for 20 minutes with a minimum cell voltage of 1.5 V
Answer: a
Explanation: The reserve capacity is the time for which the battery can supply 25 A at 80℉ with minimum cell voltage 1.75 V. It is the measurement for the total capacity of the battery.
5. What is the cold rate of a battery?
a) Lasting power of a battery on a small load
b) Rate of current for 20 minutes with a minimum cell voltage of 1.5 V
c) The current which the battery can supply continuously for 30 seconds with minimum cell voltage 1.2 V
d) Time for which the battery can supply 25 A at 80℉ with minimum cell voltage 1.75 V
Answer: c
Explanation: It is a measure of the worst conditions under which a battery is expected to deliver current, e.g., during starting the engine and operating under extreme cold. The cold rate of a battery is the current which the battery can supply continuously for 30 seconds with minimum cell voltage 1.2 V.
6. What is a twenty-hour rate of a battery?
a) The current which the battery can supply continuously for 30 seconds with minimum cell voltage 1.2 V
b) Lasting power of a battery on a small load
c) Time for which the battery can supply 25 A at 80℉ with minimum cell voltage 1.75 V
d) Rate of current for 20 minutes with a minimum cell voltage of 1.5 V
Answer: b
Explanation: A twenty-hour rate of a battery is the lasting power of a battery on a small load. During this test, the temperature should be about 80oF. This rating is important for powering accessories when the engine is not running.
7. What should a fully-charged 6 cell automotive battery indicate?
a) 12 V
b) 12.6 V
c) The specific gravity of 1.29 at 32℃
d) 12.6 V and the specific gravity of 1.29 at 32℃
Answer: d
Explanation: A fully-charged 6 cell automotive battery indicates 12.6 V and a specific gravity of 1.29 at 32℃. There should be no leak. The battery can be checked using a digital multimeter.
8. What is the number of positive plates in a battery cell?
a) One more than the negative plates
b) Two less than the negative plates
c) One less than the negative plates
d) Two more than the negative plates
Answer: c
Explanation: The number of positive plates in a battery cell is one less than the negative plates. One positive and one negative group of plates are sliding over each other, with separators sandwiched between them.
9. What is a maintenance-free battery?
a) A battery having lead-antimony plate grid
b) A battery having lead-calcium plate grid
c) A battery does not contain acid
d) A battery does not contain water
Answer: b
Explanation: A maintenance-free battery is a battery having a lead-calcium plate grid. The battery which uses this plate grid loses water very slowly.
10. Which of the following is the advantage of alkaline battery?
a) High energy density
b) Good discharge characteristics over a wide range of temperature
c) The specific gravity of electrolyte remains the same
d) Cheap raw materials are used
Answer: c
Explanation: The advantage of the alkaline battery is that the specific gravity of electrolyte remains the same. The electrolyte does not take part in chemical reactions on charging or discharging.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Charging System”.
1. Which component in the DC generator produces a magnetic field?
a) Stator
b) Commutator
c) Armature
d) Carbon brushes
Answer: d
Explanation: Carbon brushes produce the magnetic field in DC generator. The DC generator is a device which converts mechanical energy into electrical energy. It works on the principle of induced EMF.
2. Which component in alternator produces a magnetic field?
a) Frame
b) Stator
c) Regulator
d) Rotor
Answer: d
Explanation: Rotor in an alternator produces a magnetic field. An alternator is a device that converts mechanical energy to electrical energy and produces the AC current. The rotor is the moving part of the alternator.
3. Why is a thermistor used in an alternator regulator?
a) To control maximum current
b) To control maximum voltage
c) To compensate for temperature change
d) To control minimum current
Answer: c
Explanation: A thermistor is used in an alternator regulator to compensate for temperature change. It is a temperature-sensing device. It alters its physical resistance to change temperature.
4. What is the frequency of a vibrating contact type regulator for DC generator?
a) 20 per second
b) 200 per second
c) 200 per minute
d) 20 per minute
Answer: b
Explanation: The frequency of a vibrating contact type regulator for DC generator is 200 per second. The main parts of the DC generator are frame, armature, and field coils. The parts of the armature are shaft, core, commutator and coil windings.
5. At the start of the engine, the charging voltage is _______
a) Lower
b) Higher
c) Same
d) Zero
Answer: b
Explanation: The charging voltage is high at the start of the engine. The charging voltage should be less than the alternator voltage to charge the battery. The standard battery automotive battery should indicate 12.6 V at 35℃. When the engine is running, it should show 13.7 V to 14.7 V.
6. In an alternator, which component controls the output?
a) Voltage regulator
b) Cutout relay
c) Current regulator
d) Diode
Answer: a
Explanation: Voltage regulator controls the output of the alternator. A voltage regulator is designed so that it keeps a constant voltage level. The voltage regulator is used when the steady and reliable voltage is needed.
7. What is the material of an alternator frame?
a) Cast iron
b) Brass
c) Copper
d) Aluminum
Answer: d
Explanation: An alternator frame is made of aluminum. Aluminum is lightweight. It is no-magnetic. It has a higher thermal conductivity so as to keep the alternator assembly cool by more efficient transfer of heat.
8. If the lead-acid cell has a total of 17 cells, then what is the number of positive plates?
a) 9
b) 8
c) 7
d) 6
Answer: b
Explanation: The number of positive plates in the lead-acid cell is always one less than the number of negative plates. The number of negative plates = 9 and total plates are = 17, therefore, a number of positive plates = 8.
9. Which of the following is not an advantage of the alternator?
a) Higher output
b) Lower weight
c) Less maintenance
d) High efficiency
Answer: d
Explanation: With a lightweight of the alternator, the efficiency of alternator increases. As the output current does not flow through the commutator and brushes, thus surface contamination is eliminated.
10. Field coils in a generator produce permanent magnet.
a) True
b) False
Answer: b
Explanation: Field coils in a generator produce a temporary magnet. The field magnets are electromagnets. These magnets are energized by generator current. The fields magnets have a small residual magnetism this helps in providing the initial field to start the generator operation.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Conventional Fuels”.
1. How are hydrocarbons decomposed into smaller hydrocarbons?
a) By reforming
b) By refining
c) By cracking
d) By polymerization
Answer: c
Explanation: Hydrocarbons are decomposed into smaller hydrocarbons by cracking. Cracking consists of breaking down large complex hydrocarbon molecules into simpler compounds.
2. For SI engines which fuels are preferred?
a) Aromatics
b) Paraffin
c) Olefins
d) Napthenes
Answer: a
Explanation: For SI engines aromatic fuels are preferred. Aromatic compounds are ring structured. They have a benzene molecule as their central structure and also a general chemical formula is C n H 2n-6 .
3. For CI engines which fuels are preferred?
a) Napthenes
b) Paraffin
c) Olefins
d) Aromatics
Answer: b
Explanation: For CI engines paraffin fuels are preferred. The paraffin family consists of an open-chain structure with an attached branch. They are usually termed branched-chain paraffin.
4. Which molecular structure does the paraffin possess?
a) Chain saturated
b) Chain unsaturated
c) Ring saturated
d) Ring unsaturated
Answer: a
Explanation: The paraffin possesses a chain structure and is saturated in nature. In these hydrocarbons, the valency of all four carbon atoms is fully utilized by single bonds with hydrogen atoms.
5. Which of the following is the advantage of the 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) It can be stored, get mixed with air and can displace more air from the engine.
Answer: b
Explanation: The advantage of the gaseous fuel is that it can mix easily with air. Gaseous fuels are ideal fuels. They pose very few problems in using them in IC engines.
6. What is octane number of iso-octane?
a) 0
b) 30
c) 60
d) 100
Answer: d
Explanation: Iso-octane has octane number 100. The octane number fuel is defined as the percentage of iso-octane in a mixture of iso-octane and normal heptane by volume.
7. By which quantity is ignition quality of diesel fuel indicated?
a) Fire point
b) Flashpoint
c) Cetane point
d) Octane point
Answer: c
Explanation: Ignition quality of diesel fuel indicated by cetane point. Cetane number of a fuel is defined as the percentage of normal cetane in a mixture of normal cetane and α-methyl naphthalene by volume.
8. How is paraffin 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: The paraffin is represented by C n H 2n+2 . The normal paraffin hydrocarbons are of straight-chain molecular structure. Iso-butane has the same general chemical formula and molecular weight as butane.
9. What are the characteristics of good CI engine fuel?
a) High octane number
b) Very high cetane number
c) Short ignition lag
d) Short ignition lag, high cetane number, and high octane number
Answer: c
Explanation: Short ignition lags are the characteristics of good CI engine fuel. The CI engine fuel should be volatile in the operating range of temperature to produce good mixing and combustion.
10. How is the molecular structure of the straight-run gasoline changed?
a) By cracking
b) By reforming
c) By refining
d) By boiling
Answer: b
Explanation: The molecular structure of the straight-run gasoline is changed by reforming. Reforming is a cracking process which is used to convert the low antiknock quality gasoline into gasoline of higher octane rating.
This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Heat Rejection and Cooling”.
1. Why is radiator provided?
a) To cool the jacket water
b) To pressurize the cooling water
c) To provide additional water flow
d) To cool the external surface of the engine
Answer: a
Explanation: Radiator is provided to cool the jacket water. The heat from the combustion gases is transferred to the various parts of the engine like cylinder head and walls, piston and valves.
2. Why is thermostat used?
a) To control the velocity of water
b) To control the distribution of water to various cylinders
c) To control the water temperature
d) To control the pressure of water
Answer: c
Explanation: Thermostat is used to control the water temperature. Whenever the engine is started from cold, the coolant temperature has to be brought to the desired level so that the warmup time is less.
3. What is the advantage of the liquid cooling system?
a) Dependent only on water supply
b) Power absorbed by the pump is considerable
c) Even cooling
d) Very cheap
Answer: c
Explanation: The advantage of the liquid cooling system is even cooling. In this system, water is used as a coolant and made to circulate through the jackets provided around the cylinder, cylinder head, valve ports and seats.
4. What is the material of the radiator cooling tube?
a) Rubber
b) Plastic
c) Brass
d) Copper
Answer: d
Explanation: Radiator cooling tubes are made of copper. Radiator cores are classified as tubular or cellular. The main disadvantage is repairing any of the damaged tubes.
5. What is a direct system of cooling the air?
a) Cooling water flows by gravity
b) Hot water is continuously cooled and circulated
c) Hot water is simply discharged
d) Water is allowed to evaporate in the cylinder jacket
Answer: c
Explanation: In direct system of cooling air, hot water is simply discharged. In air-cooled system, a current of air is made to flow past the outside of the cylinder barrel.
6. Which pump is used in a forced cooling system?
a) Piston pump
b) Gear pump
c) Vane pump
d) Centrifugal pump
Answer: d
Explanation: Centrifugal pump is used in a forced cooling system. The pump is used to maintain the circulation of the water through the system. The power is transmitted to the pump spindle.
7. What is the purpose of the thermostat in an engine cooling system?
a) To allow the engine to warm-up quickly
b) To prevent the coolant from boiling
c) To pressurize the system
d) To indicate to the driver the coolant temperature
Answer: a
Explanation: The thermostat is used to allow the engine to warm-up quickly. The thermostat unit consists of closed bellows with a volatile liquid.
8. Why does the engine overheating happen?
a) Due to a broken fan belt
b) Due to excess coolant
c) Due to an open thermostat
d) Due to the stuck radiator pressure cap
Answer: a
Explanation: The engine overheating happens due to a broken fan belt. When a fan is broke, it cannot cool the hot water. It should be capable of removing about 30% of the heat from the combustion chamber.
9. What is the purpose of a fan in a liquid cooling system?
a) To disperse engine fumes
b) To pump cold air over the hot water
c) To cool the external surface of the engine
d) To drive airflow when the vehicle speed is low
Answer: b
Explanation: A fan in a liquid cooling system is used to pump cold air over the hot water. The fan is mounted on the impeller spindle which is driven by a suitable belt pulley arrangement.
10. How does the water circulation happen in a thermosyphon cooling system?
a) Due to conduction currents
b) Due to a gear drove water pump
c) Due to change in the density of water
d) Due to a belt-driven water impeller
Answer: a
Explanation: The water circulation happens in a thermosyphon cooling system due to conduction currents. This system is simple and automatic.
