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4

Pick up the wrong statement

A. 2-stroke engine can run in any direction

B. In 4-stroke engine, a power stroke is obtained in 4-strokes

C. Thermal efficiency of 4-stroke engine is more due to positive scavenging

D. Petrol engines occupy more space than diesel engines for same power output

Correct Answer :

D. Petrol engines occupy more space than diesel engines for same power output


Related Questions

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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

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

Alpha-methyl-naphthalene (C₁₁ H₁₀) has a cetane number of

A. 0

B. 50

C. 100

D. 120

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4

A mixture containing 65% of iso-octane and 35% of normal heptane will have

A. Cetane number 65

B. Octane number 65

C. Cetane number 35

D. Octane number 35

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4

The correct mixture strength (by weight) for petrol is about

A. 14.6 : 1

B. 18.5 : 1

C. 20.4 : 1

D. 22.6 : 1

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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

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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4

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

The knocking in diesel engines may be prevented by

A. Reducing the delay period

B. Raising the compression ratio

C. Increasing the inlet pressure of air

D. All of these

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4

Installation of supercharger on a four cycle diesel engine can result in the following percentage increase in power

A. Up to 35%

B. Up to 50%

C. Up to 75%

D. Up to 100%

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4

The frictional power (F.P.) is given by

A. F.P. = B.P. - I.P.

B. F.P. = I.P. - B.P.

C. F.P. = B.P./I.P.

D. F.P. = I.P./B.P.

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4

The cam shaft of a four stroke I.C. engine running at 1500 rpm will run at

A. 1500 rpm

B. 750 rpm

C. 3000 rpm

D. Any value independent of engine speed

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4

The ratio of the volume of charge admitted at N.T.P. to the swept volume of the piston is called

A. Mechanical efficiency

B. Overall efficiency

C. Volumetric efficiency

D. Relative efficiency

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4

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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4

Diesel engine can work on very lean air fuel ratio of the order of 30: 1. A petrol engine can also work on such a lean ratio provided

A. It is properly designed

B. Best quality fuel is used

C. Cannot work as it is impossible

D. Flywheel size is proper

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4

The cetane (C16H34) which is a straight chain paraffin, is assigned a cetane number of

A. 0

B. 50

C. 100

D. 120

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4

For the same compression ratio

A. Otto cycle is more efficient than the Diesel

B. Diesel cycle is more efficient than Otto

C. Both Otto and Diesel cycles are, equally efficient

D. Compression ratio has nothing to do with efficiency

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4

Pick up the wrong statement about supercharging

A. Supercharging reduces knocking in diesel engines

B. There can be limited supercharging in petrol engines because of detonation

C. Supercharging at high altitudes is essential

D. Supercharging results in fuel economy

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4

A diesel engine as compared to petrol engine (both running and rated load) is

A. More efficient

B. Less efficient

C. Equally efficient

D. Other factors will decide it

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4

A diesel engine, during suction stroke, draws

A. Air only

B. Diesel only

C. A mixture of diesel and air

D. None of these

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4

In order to eliminate knocking in compression ignition engines, there should be

A. Short delay period

B. Late auto-ignition

C. Low compression ratio

D. High self ignition temperature of fuel

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4

An hmh flame speed is obtained in diesel engine when air fuel ratio is

A. Uniform throughout the mixture

B. Chemically correct mixture

C. About 35% of rich mixture

D. About 10% of rich mixture

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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

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

Scavenging air in diesel engine means

A. Air used for combustion sent under pressure

B. Forced air for cooling cylinder

C. Burnt air containing products of combustion

D. Air used for forcing burnt gases out of engine's cylinder during the exhaust period

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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

Supercharging is essential in

A. Diesel engines

B. Gas turbines

C. Petrol engines

D. Aircraft engines

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4

The accumulation of carbon in a cylinder results in increase of

A. Clearance volume

B. Volumetric efficiency

C. Ignition time

D. Effective compression ratio

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4

The pressure at the end of compression, in diesel engines, is approximately

A. 10 bar

B. 20 bar

C. 25 bar

D. 35 bar

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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