Automobile Engineering Practice Set-4

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1. The self ignition temperature of Diesel as compared to petrol is

Higher

Same

Lower

Depends on fuel quality

2. In order to implement gear changes in the gear unit of an automatic transmission, a ___________ is used.

Hydraulic multi plate clutch

Magnetic clutch

Planetary gear

Synchronizer

3. The device for smoothening out the power impulses from the engine is called

Differential

Torque converter

Clutch

Flywheel

4. The aspect ratio (expressed in percentage) of the tyre is defined as the ratio of

Section height to section width

Wheel diameter to section height

Wheel diameter to section width

Section width to section height

5. The purpose of a thermostat in an engine cooling system is to

Prevent the coolant from boiling

Pressurise the system to raise the boiling point

Allow the engine to warm up quickly

Indicate the coolant temperature

6. The natural gas is compressed in a CNG cylinder at a pressure of

200bar

300bar

220bar

250bar

7. The ignition coil is used to

Step up voltage

Step down current

Step down voltage

Step up current

8. The compression ratio in petrol engine is kept less than in Diesel engine because

It makes petrol engines lighter

Less compression ratio gives better performance

Higher or equivalent compression ratio in petrol engines is not possible due to pre-ignition

It is just customary to have less compression ratio in petrol engines

9. The gradient resistance to a vehicle having a mass of 980 kg moving on an incline of 10° is

1669.4 N

16.694 N

1.6694 N

166.94 N

10. The firing order for an opposed four cylinder l.C. engine is

1-3-2-4

1-2-3-4

1-4-3-2

1-3-4-2

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11. The main purpose of an engine's air cleaner is that it

Prevents rain water from entering the engine

Prevents dust and other foreign matter from entering the engine

Reduces the engine's air intake noise

Controls the engine's air intake volume

12. The basic purpose of a four wheel drive (4WD) system is that it

Eliminates the need of snow tyres, tyre chains, etc.

Ensures that effective braking can be performed, even on slippery surfaces

Delivers improved cornering on dry road surfaces

Ensures effective transmission of engine torque to all four wheels, even on slippery road surfaces

13. The piston compression rings are made of

Bronze

Cast iron

Aluminium

Steel

14. The discharged lead acid battery has on its plates

Sulphuric acid (H₂SO₄)

Spongy lead (Pb)

Lead sulphate (PbSO₄)

Lead peroxide (PbO₂)

15. The service brakes employed in cars are generally operated

Mechanically

Pneumatically

None of these

Hydraulically

16. The sequence in which the force is transmitted through a brake system when the brake pedal is depressed is

Brake pedal, brake lines, vacuum servo mechanism, master cylinder, brake pads

Brake pedal, master cylinder, vacuum servo mechanism, brake lines, brake pads

Brake pedal, master cylinder, brake lines, vacuum servo mechanism, brake pads

Brake pedal, vacuum servo mechanism, master cylinder, brake lines, brake pads

17. The frequency of flashing of light per minute in a direction (side turn) indicator is about

90

900

9000

9

18. With the increase of battery temperature, the specific gravity of electrolyte

Decreases

Increases

Remains the same

None of these

19. The valve overlap in four stroke petrol engines is approximately

30°

60°

90°

120°

20. The heat transfer from coolant to air in the radiator of an automobile engine takes place by

Convention only

Convection and radiation

Conduction, convection and radiation

Radiation only

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21. In Spark Ignition Engine

(D) None of these Correct Answer

(A) Only air is introduced into the cylinder

(B) The mixture of air and fuel is introduced into the cylinder from carburettor

(C) Both (A) and (B)

22. The purpose of turning radius gauges is to measure the

Free plays of the steering wheel

Difference in the toe angles of the left and right wheels

Contact areas of the tyres

Turning radius of the left and right wheels

23. Which of the following indicates multi-grade oil?

API SF

API 50

SAE20 W50

SAE 30

24. The reconditioning process used to give cylinder bore surfaces a crosshatch pattern, is known as

Boring

Honing

Porous plating

Shot peening

25. The basic characteristics of a brake fluid is

Compatibility with rubber and metal parts

All of these

Low viscosity

A high boiling point

26. The main task of a battery in automobiles is to

Supply electricity to the alternator

Act as a reservoir or stabilizer of electricity

Supply a large amount of power to turn the starter motor when the engine is being started

Supply electricity to the vehicle's electrical system at all times while the engine is running

27. The caster is called positive when the top of the king pin is inclined to the

Rear of the vehicle

Left of the vehicle

Right of the vehicle

Front of the vehicle

28. The exhaust gas from petrol engine contains

All of these

Water vapours

Petrol vapours

Carbon monoxide

29. In a forced feed lubrication system, the device used to guard against excessive oil pressure, is known as

Relief valve

Balancer

Stop valve

Release chamber

30. The process of supplying the intake air to the engine cylinder at a pressure greater than the pressure of the surrounding atmosphere is known as

Detonation

Auto ignition

Scavenging

Supercharging

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31. The two kinds of piston rings are

Oil scrapper and oil control rings

Pressure and sealing rings

Compression and sliding seal rings

Compression and oil control rings

32. The main function of a master cylinder is to

Adjust the extent of brake pedal free play

Convert brake pedal force into hydraulic pressure

Ensure that all the wheel brakes are supplied with the same amount of fluid pressure

Boost the force applied to brake pedal

33. Free pedal play in car clutches is about

60 mm

25 mm

40 mm

15 mm

34. In aluminium cylinder blocks, the cylinder liners are made of

Aluminium

Cast iron

Brass

Ceramic

35. The boiling point of Diesel fuel is in the range of

180°C to 360 °C

100°C to 120°C

120°C to 180°C

70°C to 100°C

36. The compression ratio for Diesel engines usually lies in the range of

10-15

6-10

15-20

25-40

37. The purpose of a balancer shaft is to

Reduce vibrations caused by the crankshaft rotation

Adjusts the timing of the intake and exhaust valve openings

Increase inertia force of the rotating crankshaft

Balance the timing in the movement of the two groups of pistons

38. The function of positive crankcase ventilation (PCV) system is that it

Returns blow by gases from the crankcase to the intake system

Mixes fuel with air

Feeds blow by gases to the exhaust manifold

Promotes combustion by creating a swirling movement in the air-fuel mixture

39. The function of a radiator fan in the cooling system is that

It is turned by wind force as the vehicle moves forward, and its rotation drives the water pump

It draws heat out of the engine compartment

It blows air through the radiator when necessary

It cools the engine by blowing air onto the cylinder block

40. The process of removing the burnt gases from the engine cylinder by the fresh charge coming into the engine cylinder from the crankcase, is known as

Detonation

Priming

Cleaning

Scavenging

Automobile Engineering Practice Set-4

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