Automobile Engineering 1000+ MCQ with answer for ISRO Recruitment

1. The correct way to rectify an imbalanced wheel is to
A. Adjust the tyre pressure
B. Rotate the tyres
C. Adjust the damper spring tension
D. Attach appropriate weights to the wheel at appropriate positions
Answer : D

2. The octane number of compressed natural gas (CNG) is
A. 90
B. 100
C. 110
D. 120
Answer : D

3. When the front wheels of a vehicle are locked during braking, then
A. Stopping distance becomes extremely long
B. Front tyres skid across the road surface, and the vehicle spins around
C. Rear tyres skid across the road surface, and the vehicle spins around
D. Driver loses control over the steering, and the vehicle continues moving in its current direction
Answer : D

4. The function of a first compression ring (top ring) is that it
A. Increases the combustion temperature
B. Creates swirl
C. Maintains a seal and prevents the fuel leakage
D. Maintains a seal and prevents escape of burned gases and loss of pressure in the combustion chamber
Answer : D

5. The minimum parking brake force is generally ________ of gross vehicle mass (GVM).
A. 5 %
B. 10 %
C. 15 %
D. 20 %
Answer : D

6. In a four speed four stroke Diesel engine, the intake valve
A. Opens at T.D.C. and closes at B.D.C.
B. Opens at 20° before T.D.C. and closes at 35° after B.D.C.
C. Opens at 10° after T.D.C. and closes at 20° before B.D.C.
D. None of the above
Answer : B

7. When indicated power (I.P.) and frictional power (F.P.) are known, we can calculate
A. Brake power
B. Compression ratio
C. Specific air consumption
D. Mean effective pressure
Answer : A

8. The petrol engine works on
A. Otto cycle
B. Carnot cycle
C. Diesel cycle
D. Rankine cycle
Answer : A

9. The compression ratio in petrol engine is kept less than in Diesel engine because
A. It makes petrol engines lighter
B. Higher or equivalent compression ratio in petrol engines is not possible due to pre-ignition
C. Less compression ratio gives better performance
D. It is just customary to have less compression ratio in petrol engines
Answer : B

10. In radial tyres
A. One ply layer runs diagonally one way and another layer runs diagonally the other way
B. All plies run parallel to one another and vertical to tyre bead
C. Inner tubes are always used
D. None of these
Answer : B

11. The rigid suspension is beneficial when
A. It is desired to reduce the unsprung mass
B. It is desired to have more flexibility in design
C. It is desired to improve tyre to ground contact characteristics
D. Large changes in load make it necessary to have a large suspension stroke
Answer : D

12. The combustion process in a Diesel engine is a
A. Constant volume process
B. Constant pressure process
C. Constant temperature process
D. Adiabatic process
Answer : B

13. A petrol engine of a car develops 125 Nm torque at 2700 r.p.m. The car is driven in second gear having gear ratio of 1.75. The final drive ratio is 4.11. If the overall transmission efficiency is 90%, then the torque available at the driving wheels is
A. 8.091 Nm
B. 80.91 Nm
C. 809.1 Nm
D. 8091 Nm
Answer : C

14. The function of a second ring is that it is a
A. Back up compression ring which will work in place of the top ring when it is broken
B. Compression ring and aids the top ring in sealing and cooling
C. Back up oil control ring which will work in place of the bottom ring when it is broken
D. Cushion ring which prevents piston slap and knock
Answer : B

15. The effect of having excess camber is
A. Excessive steering alignment torque
B. Hard steering
C. Too much traction
D. Uneven tyre wear
Answer : D

16. The frequency of flashing of light per minute in a direction (side turn) indicator is about
A. 9
B. 90
C. 900
D. 9000
Answer : B

17. The ease with which petrol vaporizes is called its
A. Oxidation
B. Octane number
C. Volatility
D. Cetane number
Answer : C

18. The rating of C.I. engine fuel (Diesel) is given by
A. Octane number
B. Performance number
C. Cetane number
D. None of these
Answer : C

19. In automobiles G.V.W. refers to
A. Gross vehicle width
B. Gross vehicle weight
C. Gross vehicle wheel base
D. Gross vehicle wheel track
Answer : B

20. The exhaust gas from petrol engine contains
A. Petrol vapours
B. Water vapours
C. Carbon monoxide
D. All of these
Answer : D

21. The octane rating of petrol commercially available is
A. 85-95
B. 95-100
C. 100-110
D. 110-125
Answer : A

22. The negative plates of a lead acid battery has
A. Lead peroxide (PbO?)
B. Spongy lead (Pb)
C. Lead sulphate (PbSO?)
D. Sulphuric acid (H?SO?)
Answer : B

23. The reconditioning process used to give cylinder bore surfaces a crosshatch pattern, is known as
A. Honing
B. Porous plating
C. Boring
D. Shot peening
Answer : A

24. The characteristic that is enhanced by the use of cylinder sleeves is
A. Cooling efficiency
B. Resistance to wear
C. Lubrication performance
D. None of these
Answer : B

25. In a forced feed lubrication system, the device used to guard against excessive oil pressure, is known as
A. Release chamber
B. Balancer
C. Relief valve
D. Stop valve
Answer : C

26. The purpose of transmission in an automobile is
A. To vary the speed of automobile
B. To vary the torque at the wheels
C. To vary the power of automobile
D. None of these
Answer : B

27. The boiling point of Diesel fuel is in the range of
A. 70°C to 100°C
B. 100°C to 120°C
C. 120°C to 180°C
D. 180°C to 360 °C
Answer : D

28. In a Diesel engine, the function of a fuel injector is to
A. Mix the fuel and air
B. Ignite the air-fuel mixture
C. Provide flame front for ignition
D. Spray atomized fuel in the cylinder
Answer : D

29. The problems caused by the wheel imbalance are
A. Hard steering and hard ride
B. Poor acceleration and hard steering
C. Steering wheel vibrations and uneven tyre wear
D. Poor acceleration and reduced fuel efficiency
Answer : C

30. Caster is a
A. Forward tilt of the kingpin
B. Backward tilt of the kingpin
C. Either 'A' or 'B'
D. None of these
Answer : C

31. The braking control type traction control system (TCS) generally operates in the speed range of
A. Less than 20 kmph
B. Less than 40 kmph
C. Less than 60 kmph
D. More than 60 kmph
Answer : B

32. Which of the following oil is more viscous?
A. SAE 30
B. SAE 40
C. SAE 70
D. SAE 80
Answer : D

33. The most commonly used supplementary restraint system (SRS) component is
A. Seat belt
B. Brake
C. Airbag
D. Steering
Answer : C

34. The number of exhaust manifolds in a V6 engine is
A. One
B. Two
C. Four
D. Eight
Answer : B

35. The connecting rods are generally made of ________ shaped crosssection.
A. I
B. C
C. L
D. H
Answer : A

36. The negative terminal post on the top of a battery is
A. Smaller than the positive terminal post
B. Larger than the positive terminal post
C. Of the same size as the positive terminal post
D. None of these
Answer : A

37. The air resistance to a car at 20 kmph is R. The air resistance at 40 kmph will be
A. R
B. 2 R
C. 4R
D. 4 R²
Answer : C

38. The crescent shaped cavity on the piston head top surface is called as
A. Piston oil hole
B. Snap ring
C. Valve recess
D. Valve clearance
Answer : C

39. The heat transfer from coolant to air in the radiator of an automobile engine takes place by
A. Radiation only
B. Convention only
C. Convection and radiation
D. Conduction, convection and radiation
Answer : C

40. Vulcanizing means
A. Heating rubber under pressure
B. Spraying with special paint
C. Melting rubber while stirring it
D. None of these
Answer : A

41. The aluminium alloy is used in cylinder blocks because
A. It is lighter and has good heat dissipation characteristics
B. Material cost is low
C. It does not require any cylinder liners
D. The piston is also made of aluminium alloy
Answer : A

42. The oil pump is driven by the
A. Camshaft
B. Alternator shaft
C. Crankshaft via drive belt
D. Crankshaft directly
Answer : D

43. The main merit of a multi cylinder type cylinder sleeve is
A. Smaller engine dimensions
B. Better cooling efficiency
C. High rigidity
D. None of these
Answer : A

44. The advantage of the fuel injection system over the carburettor system is
A. Improved fuel efficiency
B. Improved emission
C. Improved power output
D. All of these
Answer : D

45. How many cells are used in a 12 volt car battery?
A. 2
B. 4
C. 6
D. 8
Answer : C

46. If the air-fuel mixture in a spark ignition engine is too rich, then airfuel ratio is about
A. 17 : 1
B. 15 : 1
C. 13 : 1
D. 10 : 1
Answer : D

47. The ignition coil is used to
A. Step up current
B. Step down current
C. Step up voltage
D. Step down voltage
Answer : C

48. The function of positive crankcase ventilation (PCV) system is that it
A. Mixes fuel with air
B. Promotes combustion by creating a swirling movement in the air-fuel mixture
C. Returns blow by gases from the crankcase to the intake system
D. Feeds blow by gases to the exhaust manifold
Answer : C

49. The acid used in automobile battery is
A. Hydrochloric acid
B. Hydrofluoric acid
C. Nitric acid
D. Sulphuric acid
Answer : D

50. The ignition in a spark ignition engine takes place when the piston is
A. Exactly at the T.D.C. position on its compression stroke
B. Approaching the T.D.C. position on its compression stroke
C. Leaving the T.D.C. position on its compression stroke
D. Approaching the T.D.C position on its exhaust stroke
Answer : B