1000+ Automobile Engineering MCQ for JEE Main [Solved]

1. A basic difference between the spark ignition engine and the Diesel engine is that the
A. Diesel engine compresses air alone instead of an air-fuel mixture
B. Air temperature ignites the fuel in the Diesel engine
C. Fuel is sprayed into the combustion chamber in the Diesel engine as the piston nears T.D.C. on the compression stroke
D. All of the above
Answer : D

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

3. 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

4. The painting of automobiles is done to
A. Prevent rust from growing on the body
B. Improve its external appearance
C. Retain the characteristics of steel for long
D. All of these
Answer : D

5. 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

6. The firing order for an opposed four cylinder l.C. engine is
A. 1-2-3-4
B. 1-3-4-2
C. 1-4-3-2
D. 1-3-2-4
Answer : C

7. 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

8. 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

9. The seat belt tensioners are built in the
A. Front seats
B. Shoulder anchors
C. Seat belt retractors
D. Seat belt buckles
Answer : C

10. Damper is also known as
A. Shock absorber
B. Torsion bar
C. Spring
D. Radius rod
Answer : A

11. In Diesel engines, during suction stroke, ________ is drawn in the cylinder.
A. Air and fuel
B. Only fuel
C. Only air
D. None of these
Answer : C

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

13. Free pedal play in car clutches is about
A. 15 mm
B. 25 mm
C. 40mm
D. 60 mm
Answer : B

14. The valve tappet clearance is measured by
A. Screw pitch gauge
B. Engineering scale
C. Feeler gauge
D. Vernier caliper
Answer : C

15. The main function of intake manifold is that it
A. Promotes the mixture of air and fuel
B. Reduces intake noise
C. Cools the intake air to a suitable temperature
D. Distributes intake air equally to the cylinders
Answer : D

16. In an engine, the temperature of the piston will be more at the
A. Crown of the piston
B. Skirt of the piston
C. Piston walls
D. Piston rings
Answer : A

17. In a square type engine
A. Geometrical shape is square
B. Diameter and length of piston are same
C. Two cylinders are placed horizontal and two vertical
D. Stroke length and cylinder bore are same
Answer : D

18. A four cylinder engine has a capacity of 2.4 litres. The swept volume of one cylinder is
A. 400 cm³
B. 600 cm³
C. 1200 cm³
D. 2400 cm³
Answer : B

19. The component of the oil filter that prevents the passage of metal particles and sludge is
A. Element
B. Relief valve
C. Check valve
D. Case
Answer : A

20. The materials used for cylinder block are
A. Cast iron and steel
B. Cast iron and aluminium alloy
C. Steel and aluminium alloy
D. Brass and steel
Answer : B

21. In a four cylinder inline engine, the number of firing strokes in one revolution of the crank is
A. 1
B. 2
C. 3
D. 4
Answer : B

22. Incorrect steering axis inclination (S.A.I.) causes
A. Tendency to assume toe-out orientation
B. Generation of a braking effect at tight corners
C. Poor recovery of the steering wheel after making a turn
D. The vehicle to pull to the side of lesser inclination
Answer : C

23. The basic function of the suspension is to
A. Absorbs vibration and impact forces from the road surface
B. Ensure that the steering wheel can deliver a suitable amount of steering force
C. Ensure that wheel alignment is not disturbed during driving
D. Automatically correct the effects of over steering
Answer : A

24. The function of a proportioning control valve (PCV) in a brake system is to
A. Ensure that equal pressure is supplied to the front and rear brakes throughout every braking operation
B. Reduce the brake fluid pressure when the brakes approach their lockup point
C. Cause less brake fluid pressure to act on the front brakes than on the rear brakes when the fluid pressure exceeds a predetermined level
D. Cause less brake fluid pressure to act on the rear brakes than on the front brakes when the fluid pressure exceeds a predetermined level.
Answer : D

25. In vehicles with tilt steering, the steering column is pivoted in
A. Upper bracket
B. Lower bracket
C. Tilt bracket
D. Steering yoke joint
Answer : B

26. The timing belt is attached to the camshaft pulley and
A. Timing belt drive pulley
B. Distributor
C. Radiator fan pulley
D. Alternator pulley
Answer : A

27. The function of a connecting rod is
A. To turn the flywheel
B. To drive the drive plate
C. To drive the fuel pump
D. To transmit motion of the piston to the crankshaft
Answer : D

28. The difference between DOT 3 and DOT 4 brake fluids is
A. DOT 4 fluids have a higher boiling point than DOT 3 fluid
B. DOT 4 fluids have a lower boiling point than DOT 3 fluid
C. DOT 3 and DOT 4 fluids have the same boiling point, but DOT 4 fluid has a longer service life
D. DOT 4 fluid is more resistant to freezing than DOT 3 fluid
Answer : A

29. The mechanical efficiency (?m) of an I.C. engine is equal to (where I.P. = Indicated power, B.P. = Brake power and F.P. = Frictional power)
A. I.P/B.P.
B. B.P/I.P.
C. B.P/F.P.
D. F.P/B.P.
Answer : B

30. 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

31. 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

32. The composition of the electrolyte in a fully charged battery is that
A. The electrolyte is pure distilled water
B. The electrolyte is pure sulphuric acid
C. The electrolyte is a mixture of 64% distilled water and 36% sulphuric acid by weight
D. The electrolyte is a mixture of 90% distilled water and 10% sulphuric acid by weight
Answer : C

33. The included angle is the sum of the
A. Camber and castor
B. Castor and S.A.I.
C. Camber and S.A.I.
D. Camber and toe in
Answer : C

34. 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

35. The lubrication oil flow in an engine is in the order as
A. Oil strainer, oil pump, relief valve, oil filter, cylinder block, cylinder head and oil pan
B. Oil pump, oil strainer, relief valve, oil filter, cylinder block, cylinder head and oil pan
C. Oil strainer, oil filter, relief valve, oil pump, cylinder block, cylinder head and oil pan
D. Oil strainer, oil pump, relief valve, oil filter, cylinder head, cylinder block and oil pan
Answer : A

36. The purpose of a cylinder head gasket is to
A. Prevent the combustion gases from leaking from the joint between the cylinder block and the cylinder head
B. Prevent engine oil from going into combustion chamber
C. Removes impurities from cylinder head lubricating oil
D. None of the above
Answer : A

37. An oil filter bypass valve opens when the
A. Engine is cold
B. Engine overheats
C. Oil filter becomes clogged
D. Engine runs at high speed
Answer : C

38. Which of the following parameter can be adjusted by modifying the tie rod attachment length?
A. Camber
B. Caster
C. Toe
D. Steering gear ratio
Answer : C

39. 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

40. The battery is an electrochemical device, which means battery
A. Makes chemicals by mechanical means
B. Uses chemical action to provide electricity
C. Has curved plates instead of flat plates
D. Does not use an electrolyte
Answer : B

41. A worm gear is used as the pinion for the rack and pinion type of steering gearbox, because it
A. Improves steering comfort when steering wheel is turned to effect small changes in the direction of forward motion
B. Allows the steering wheel to be turned by a greater amount when steering
C. Makes the steering more responsive
D. Reduces the amount of kickback for large steering angles
Answer : A

42. The gradient resistance to a vehicle having a mass of 980 kg moving on an incline of 10° is
A. 1.6694 N
B. 16.694 N
C. 166.94 N
D. 1669.4 N
Answer : D

43. Highest useful compression ratio (HUCR) is the highest compression ratio at which the
A. Engine can run
B. Engine gives maximum output
C. Engine is most efficient
D. Fuel can be used in a test engine without knocking
Answer : D

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

45. 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

46. If a tyre is designated as 175/65 R-14 82-S, then the aspect ratio for the tyre is
A. 175
B. 65
C. 14
D. 82
Answer : B

47. In aluminium cylinder blocks, the cylinder liners are made of
A. Aluminium
B. Ceramic
C. Brass
D. Cast iron
Answer : D

48. 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

49. In a four stroke engine for each crankshaft revolution, the camshaft revolves
A. One half turn
B. One turn
C. Two turns
D. Four turns
Answer : A

50. The effect of vapour locking on the brake performance is that the
A. Brakes function more effectively
B. Brakes fail completely
C. Brake operation is delayed after depression of the brake pedal
D. Vapour locking has no effect on brake performance
Answer : B