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4

Supercharging is the process of supplying the intake air to the engine cylinder at a density _________ the density of the surrounding atmosphere.

A. Equal to

B. Less than

C. Greater than

D. None of these

Correct Answer :

C. Greater than


Related Questions

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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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Combustion in compression ignition engines is

A. Homogeneous

B. Heterogeneous

C. Both (A) and (B)

D. Laminar

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In a four stroke cycle petrol engine, the inlet valve

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

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

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

D. May open or close anywhere

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The operation of forcing additional air under pressure into the engine cylinder is known as

A. Supercharging

B. Carburetion

C. Turbulence

D. Delay period

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The pressure at the end of compression in the case of diesel engine is of the order of

A. 6 kg/cm

B. 12 kg/cm

C. 20 kg/cm

D. 35 kg/cm

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Which of the following is not an interns combustion engine?

A. 2-stroke petrol engine

B. 4-stroke petrol engine

C. Diesel engine

D. Steam turbine

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The power actually developed by the engine cylinder of an I.C. engine is known as

A. Theoretical power

B. Actual power

C. Indicated power

D. None of these

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Supercharging is the process of

A. Supplying the intake of an engine with air at a density greater than the density of the surrounding atmosphere

B. Providing forced cooling air

C. Injecting excess fuel for raising more loads

D. Supplying compressed air to remove combustion products fully

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4

In a petrol engine, the mixture has the lowest pressure at the

A. Beginning of suction stroke

B. End of suction stroke

C. End of compression stroke

D. None of these

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4

The ratio of the brake power to the indicated power is called

A. Mechanical efficiency

B. Overall efficiency

C. Indicated thermal efficiency

D. Volumetric efficiency

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Which one of the following event would reduce volumetric efficiency of a vertical compression ignition engine?

A. Inlet valve closing after bottom dead centre

B. Inlet valve closing before bottom dead centre

C. Inlet valve opening before top dead centre

D. Exhaust valve closing after top dead centre

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4

A fuel of cetane number 40 has the same ignition quality as a mixture of

A. 40% cetane and 60% alpha methyl naphthalene

B. 40% alpha methyl naphthalene and 60% cetane

C. 40% petrol and 60% diesel

D. 40% diesel and 60% petrol

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4

The fuel in diesel engine is normally injected at pressure of

A. 5-10 kg/cm²

B. 20-25 kg/cm²

C. 60-80 kg/cm²

D. 90-130 kg/cm²

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Which of the following does not relate to a spark ignition engine?

A. Ignition coil

B. Spark plug

C. Carburettor

D. Fuel injector

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Most high speed compression engines operate on

A. Diesel cycle

B. Otto cycle

C. Dual combustion cycle

D. Special type of air cycle

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In a cycle, the spark lasts roughly for

A. 1 sec

B. 0.1 sec

C. 0.01 sec

D. 0.001 sec

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The effective inhibitor of pre-ignition is

A. Alcohol

B. Water

C. Lead

D. None of these

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4

In compression ignition engines, swirl denotes a

A. Haphazard motion of the gases in the chamber

B. Rotary motion of the gases in the chamber

C. Radial motion of the gases in the chamber

D. None of the above

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The output of a diesel engine can be increased without increasing the engine revolution or size in following way

A. Feeding more fuel

B. Heating incoming air

C. Scavenging

D. Supercharging

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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

Pour point of fuel oil is the

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

The reflectivity depends upon

A. Geometry of the reflector

B. Energy of neutrons

C. Properties of the reflector

D. All of these

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Detonation is harmful due to

A. Increase in the rate of heat transfer, there is a reduction in the power output and efficiency of the engine

B. Excessive turbulence which removes most of the insulating gas boundary layer from the cylinder walls

C. High intensity of knock causes crankshaft vibration and the engine runs rough

D. None of the above

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4

The method of determination of indicated power of a multi cylinder spark ignition engine is by the use of

A. Morse test

B. Prony brake test

C. Motoring test

D. Heat balance test

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As a result of detonation in an I.C. engine, following parameter attains very high value

A. Peak pressure

B. Rate of rise of pressure

C. Rate of rise of temperature

D. Peak temperature

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The thermodynamic cycle on which the petrol engine works, is

A. Otto cycle

B. Joule cycle

C. Rankine cycle

D. Stirling cycle

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The knock in diesel engine occurs due to

A. Instantaneous and rapid burning of the first part of the charge

B. Instantaneous auto ignition of last part of charge

C. Delayed burning of the first part of the charge

D. Reduction of delay period

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4

The voltage required to produce a spark across the gap, between the sparking points is

A. 2000 to 4000 volts

B. 4000 to 6000 volts

C. 6000 to 10,000 volts

D. 10,000 to 12,000 volts

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The knocking in spark ignition engines can be reduced by

A. Retarding the spark

B. Increasing the engine speed

C. Both (A) and (B)

D. None of these

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A stoichiometric air-fuel ratio is

A. Chemically correct mixture

B. Lean mixture

C. Rich mixture for idling

D. Rich mixture for over loads