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4

In the crankcase method of scavenging, the air pressure is produced by

A. Supercharger

B. Centrifugal pump

C. Natural aspirator

D. Movement of engine piston

Correct Answer :

D. Movement of engine piston


Related Questions

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4

A petrol engine has compression ratio from

A. 6 to 10

B. 10 to 15

C. 15 to 25

D. 25 to 40

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4

The higher combustion chamber wall temperature in compression ignition engines will _________ knocking tendency.

A. Increase

B. Reduce

C. Not effect

D. None of these

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4

The specific fuel consumption of a petrol engine compared to diesel engine of same H.P. is

A. Same

B. More

C. Less

D. Less or more depending on operating conditions

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4

In a typical medium speed 4-stroke cycle diesel engines

A. Exhaust valve opens at 35° before bottom dead centre and closes at 20° after top dead centre

B. Exhaust valve opens at bottom dead centre and closes at top dead centre

C. Exhaust valve opens just after bottom dead centre and closes just before top dead centre

D. May open and close anywhere

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4

The air standard efficiency of an I.C. engine depends on

A. Fuel used

B. Speed of engine

C. Compression ratio

D. None of these

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4

The spark ignition engines are governed by

A. Hit and miss governing

B. Qualitative governing

C. Quantitative governing

D. Combination of (B) and (C)

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4

Iso-octane (C8H18) has octane number of

A. 0

B. 50

C. 100

D. 120

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4

Which of the following is the lightest and most volatile liquid fuel?

A. Diesel

B. Kerosene

C. Fuel oil

D. Gasoline

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4

Stoichiometric ratio is

A. Chemically correct air-fuel ratio by weight

B. Chemically correct air-fuel ratio by volume

C. Actual air-fuel ratio for maximum efficiency

D. None of the above

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4

An engine indicator is used to determine the following

A. Speed

B. Temperature

C. Volume of cylinder

D. m.e.p. and I.H.P.

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4

The mean effective pressure obtained from engine indicator indicates the

A. Maximum pressure developed

B. Minimum pressure

C. Instantaneous pressure at any instant

D. Average pressure

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4

A stoichiometric air-fuel ratio is

A. Chemically correct mixture

B. Lean mixture

C. Rich mixture for idling

D. Rich mixture for over loads

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4

In a typical medium speed 4-stroke cycle diesel engine the inlet valve

A. Opens at 20° before top dead center and closes at 35° after the bottom dead center

B. Opens at top dead center and closes at bottom dead center

C. Opens at 10° after top dead center and closes 20° before the bottom dead center

D. May open or close anywhere

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4

Antiknock for compression ignition engines is

A. Napthene

B. Tetra ethyl lead

C. Amyl nitrate

D. Hexadecane

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4

For the same power developed in I.C. engines, the cheaper system is

A. Naturally aspirated

B. Supercharged

C. Centrifugal pump

D. Turbo charger

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4

A fuel of an octane number rating of 75 matches in knocking intensity as a mixture of

A. 75% iso-octane and 25% normal heptane

B. 75% normal heptane and 25% iso-octane

C. 75% petrol and 25% diesel

D. 75% diesel and 25% petrol

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4

The ignition quality of petrol is expressed by

A. Cetane number

B. Octane number

C. Calorific value

D. All of these

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4

The injection pressure in a diesel engine is about

A. 10 bar

B. 100 bar

C. 150 bar

D. 500 bar

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4

The maximum propulsive efficiency of a turbojet engine is at a speed of

A. 1000 km/h

B. 2000 km/h

C. 2400 km/h

D. 3000 km/h

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4

The object of supercharging the engine is

A. To reduce mass of the engine per brake power

B. To reduce space occupied by the engine

C. To increase the power output of an engine when greater power is required

D. All of the above

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4

Does the supply of scavenging air at a density greater than that of atmosphere mean engine is supercharged?

A. Yes

B. No

C. To some extent

D. Unpredictable

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4

In a four stroke cycle diesel engine, the inlet valve

A. Opens at 20° before top dead centre and closes at 40° after bottom dead centre

B. Opens at 20° after top dead centre and closes at 20° before bottom dead centre

C. Opens at top dead centre and closes at bottom dead centre

D. May open and close anywhere

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4

The inlet value of a four stroke cycle I.C engine remains open for nearly

A. 180°

B. 125°

C. 235°

D. 200°

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4

In a four stroke cycle diesel engine, the exhaust valve

A. Opens at 30° before bottom dead centre and closes at 10° after top dead centre

B. Opens at 30° after bottom dead centre and closes at 10° before top dead centre

C. Opens at bottom dead centre and closes at top dead centre

D. May open and close anywhere

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4

Volatility of diesel fuel oil is

A. Minimum temperature to which oil is heated in order to give off inflammable vapours in sufficient quantity to ignite momentarily when brought in contact with a flame

B. Temperature at which it solidifies or congeals

C. It catches fire without external aid

D. Indicated by 90% distillation temperature, i.e., when 90% of sample oil has distilled off

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4

In a four stroke cycle engine, the sequence of operations is

A. Suction, compression, expansion and exhaust

B. Suction, expansion, compression and exhaust

C. Expansion, compression, suction and exhaust

D. Compression, expansion, suction and exhaust

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4

The knocking tendency in compression ignition engines for a given fuel will be

A. Enhanced by decreasing compression ratio

B. Enhanced by increasing compression ratio

C. Dependent on other factors

D. None of the above

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4

The brake power is the power available

A. In the engine cylinder

B. At the crank shaft

C. At the crank pin

D. None of these

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4

Air fuel ratio at which a petrol engine cannot work is

A. 8 : 1

B. 10 : 1

C. 15 : 1

D. 20 : 1 and less

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4

Pre-ignition is caused by the spontaneous combustion of the mixture before the end of the compression stroke, and is due to

A. Cylinder walls being too hot

B. Overheated spark plug points

C. Red hot carbon deposits on cylinder walls

D. Any one of these