Automobile Engineering Practice Set-4

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

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

Less compression ratio gives better performance

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

It makes petrol engines lighter

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

10-15

6-10

15-20

25-40

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

Pressurise the system to raise the boiling point

Indicate the coolant temperature

Prevent the coolant from boiling

Allow the engine to warm up quickly

4. Free pedal play in car clutches is about

40 mm

60 mm

15 mm

25 mm

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

Mixes fuel with air

Feeds blow by gases to the exhaust manifold

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

Returns blow by gases from the crankcase to the intake system

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

Prevents dust and other foreign matter from entering the engine

Reduces the engine's air intake noise

Controls the engine's air intake volume

Prevents rain water from entering the engine

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

Conduction, convection and radiation

Convection and radiation

Convention only

Radiation only

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

API 50

SAE 30

SAE20 W50

API SF

9. In Spark Ignition Engine

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

(C) Both (A) and (B)

(A) Only air is introduced into the cylinder

(D) None of these Correct Answer

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

Brass

Ceramic

Aluminium

Cast iron

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11. The service brakes employed in cars are generally operated

Hydraulically

Mechanically

None of these

Pneumatically

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

Clutch

Flywheel

Torque converter

Differential

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

1.6694 N

166.94 N

1669.4 N

16.694 N

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

Porous plating

Honing

Shot peening

Boring

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

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

Delivers improved cornering on dry road surfaces

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

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

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

Rear of the vehicle

Right of the vehicle

Left of the vehicle

Front of the vehicle

17. The discharged lead acid battery has on its plates

Sulphuric acid (H₂SO₄)

Lead peroxide (PbO₂)

Lead sulphate (PbSO₄)

Spongy lead (Pb)

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

Release chamber

Balancer

Stop valve

Relief valve

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

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

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

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

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

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

Act as a reservoir or stabilizer of electricity

Supply electricity to the alternator

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

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

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21. The piston compression rings are made of

Aluminium

Bronze

Cast iron

Steel

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

Magnetic clutch

Hydraulic multi plate clutch

Planetary gear

Synchronizer

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

It blows air through the radiator when necessary

It cools the engine by blowing air onto the cylinder block

It draws heat out of the engine compartment

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

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

1-2-3-4

1-3-4-2

1-4-3-2

1-3-2-4

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

Remains the same

None of these

Increases

Decreases

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

Free plays of the steering wheel

Turning radius of the left and right wheels

Contact areas of the tyres

Difference in the toe angles of the left and right wheels

27. The basic characteristics of a brake fluid is

All of these

Low viscosity

A high boiling point

Compatibility with rubber and metal parts

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

90°

120°

60°

30°

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

900

90

9

9000

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

Section height to section width

Section width to section height

Wheel diameter to section height

Wheel diameter to section width

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

250bar

220bar

200bar

300bar

32. 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

Scavenging

Cleaning

Priming

Detonation

33. The main function of a master cylinder is to

Boost the force applied to brake pedal

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

Adjust the extent of brake pedal free play

Convert brake pedal force into hydraulic pressure

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

Same

Higher

Depends on fuel quality

Lower

35. The purpose of a balancer shaft is to

Reduce vibrations caused by the crankshaft rotation

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

Increase inertia force of the rotating crankshaft

Adjusts the timing of the intake and exhaust valve openings

36. 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

Supercharging

Scavenging

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

100°C to 120°C

70°C to 100°C

180°C to 360 °C

120°C to 180°C

38. The exhaust gas from petrol engine contains

Water vapours

Carbon monoxide

Petrol vapours

All of these

39. The two kinds of piston rings are

Compression and sliding seal rings

Compression and oil control rings

Oil scrapper and oil control rings

Pressure and sealing rings

40. The ignition coil is used to

Step down current

Step up voltage

Step up current

Step down voltage

Automobile Engineering Practice Set-4

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