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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

Correct Answer :

B. Rotary motion of the gases in the chamber


Related Questions

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4

The purpose of testing an internal combustion engine is

A. To determine the information, which cannot be obtained by calculations

B. To conform the data used in design, the validity of which may be doubtful

C. To satisfy the customer regarding the performance of the engine

D. All of the above

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4

The compensating jet in a carburettor supplies almost constant amount of petrol at all speeds because the

A. Jet area is automatically varied depending on the suction

B. The flow from the main jet is diverted to the compensating jet with increase in speed

C. The diameter of the jet is constant and the discharge coefficient is invariant

D. Flow is produced due to the static head in the float chamber

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4

In a four stroke cycle, the minimum temperature inside the engine cylinder occurs at the

A. Beginning of suction stroke

B. End of suction stroke

C. Beginning of exhaust stroke

D. End of exhaust stroke

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4

A 5 BHP engine running at full load would consume diesel of the order of

A. 0.3 kg/hr

B. 1 kg/hr

C. 3 kg/hr

D. 5 kg/hr

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4

In petrol engines, advancing of the spark timing will _________ the knocking tendency.

A. Not effect

B. Decrease

C. Increase

D. None of these

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4

The air-fuel ratio in petrol engines is controlled by

A. Controlling valve opening/closing

B. Governing

C. Injection

D. Carburetion

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4

The octane number of petrol, generally available, is

A. 20 to 40

B. 40 to 60

C. 60 to 80

D. 80 to 100

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4

The object of providing masked inlet valve in the air passage of compression ignition engines is to

A. Enhance flow rate

B. Control air flow

C. Induce primary swirl

D. Induce secondary turbulence

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4

The basic requirement of a good combustion chamber is

A. Minimum turbulence

B. Low compression ratio

C. High thermal efficiency and power output

D. Low volumetric efficiency

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4

If the speed of the engine is increased, the indicated power will

A. Increase

B. Decrease

C. Remain same

D. None of these

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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

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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4

If the temperature of intake air in internal combustion engine increases, then its efficiency will

A. Remain same

B. Decrease

C. Increase

D. None of these

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4

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

Air fuel ratio for idling speed of a petrol engine is approximately

A. 1 : 1

B. 5 : 1

C. 10 : 1

D. 15 : 1

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4

If V₁ is the jet velocity and V₀ is the vehicle velocity, then propulsive efficiency of a turbojet engine is

A. V₁/(V₀ + V₁)

B. V₀/(V₀ + V₁)

C. 2V₀/(V₀ + V₁)

D. 2V₁/(V₀ + V₁)

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4

Compression ratio of I.C. Engines is

A. The ratio of volumes of air in cylinder before compression stroke and after compression stroke

B. Volume displaced by piston per stroke and clearance volume in cylinder

C. Ratio of pressure after compression and before compression

D. Swept volume/cylinder volume

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4

The exhaust valve in a four stroke cycle petrol engine

A. Opens at 50° before bottom dead centre and closes at 15° after top dead centre

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

C. Opens at 50° after bottom dead centre and closes at 15° before top dead centre

D. May open and close anywhere

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4

The inlet valve of a four stroke cycle internal combustion engine remains open for

A. 130°

B. 180°

C. 230°

D. 270°

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4

Diesel as compared to petrol is

A. Highly ignitable

B. More difficult to ignite

C. Less difficult to ignite

D. None of these

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4

A supercharged engine as compared to an ordinary engine

A. Is lighter

B. Requires smaller foundations

C. Consumes less lubricating oil

D. All of these

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4

The combustion in compression ignition engines is

A. Homogeneous

B. Heterogeneous

C. Both (A) and (B)

D. None of these

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4

The cetane number of diesel oil, generally available, is

A. 20 to 25

B. 25 to 30

C. 30 to 40

D. 40 to 55

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4

The compression 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

The ratio of the indicated thermal efficiency to the air standard efficiency is known as

A. Mechanical efficiency

B. Overall efficiency

C. Volumetric efficiency

D. Relative efficiency

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4

The scavenging efficiency of a four stroke cycle diesel engine is

A. Below 50%

B. Between 50 and 85%

C. Between 85 and 95%

D. Between 95 and 100%

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4

In petrol engines, the delay period is of the order of

A. 0.001 second

B. 0.002 second

C. 0.003 second

D. 0.004 second

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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

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 fuels in order of decreasing knock tendency for spark ignition engines are

A. Paraffin, aromatic, napthene

B. Paraffin, napthene, aromatic

C. Napthene, aromatics, paraffin

D. Napthene, paraffin, aromatic