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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

Correct Answer :

D. Supercharging


Related Questions

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4

Which of the following statement is correct?

A. Compression ratio for petrol engines varies from 6 to 10

B. Higher compression ratio in diesel engines results in higher pressures

C. Petrol engines work on Otto cycle

D. All of the above

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4

The mechanical efficiency (ηm) of the engine is given by

A. ηm = B.P/I.P

B. ηm = I.P/B.P

C. ηm = (B.P × I.P)/100

D. None of these

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4

The fuel air ratio in a petrol engine fitted with suction carburettor, operating with dirty air filter as compared to clean filter will be

A. Higher

B. Lower

C. Remain unaffected

D. None of the above

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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

During idling, a petrol engine requires _________ mixture.

A. Lean

B. Rich

C. Chemically correct

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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4

Number of working strokes per min. for a two stroke cycle engine is _________ the speed of the engine in r.p.m.

A. Equal to

B. One-half

C. Twice

D. Four-times

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4

The pressure and temperature at the end of compression stroke in a petrol engine are of the order of

A. 4-6 kg/cm² and 200-250°C

B. 6-12 kg/cm² and 250-350°C

C. 12-20 kg/cm² and 350-450°C

D. 20-30 kg/cm² and 450-500°C

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4

A gas engine has a swept volume of 300 cm3 and clearance volume of 25 cm3. Its volumetric efficiency is 0.88 and mechanical efficiency is 0.90. The volume of the mixture taken in per stroke is

A. 248 cm3

B. 252 cm3

C. 264 cm3

D. 286 cm3

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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

The increase of efficiency of a compression ignition engine, as the load decreases, is due to

A. Higher maximum temperature

B. Qualitative governing

C. Quantitative governing

D. Hit and miss governing

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4

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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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 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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4

The process of breaking up or a liquid into fine droplets by spraying is called

A. Vaporisation

B. Carburetion

C. Ionisation

D. Atomisation

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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

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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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

Engine pistons are usually made of aluminium alloy because it

A. Is lighter

B. Wear is less

C. Absorbs shocks

D. Is stronger

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4

All heat engines utilize

A. Low heat value of oil

B. High heat value of oil

C. Net calorific value of oil

D. Calorific value of fuel

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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

In a diesel engine, the duration between the time of injection and ignition, is known as

A. Pre-ignition period

B. Delay period

C. Period of ignition

D. Burning period

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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 turbine of the turboprop engine is __________ that of the turbojet engine.

A. Same as

B. Smaller than

C. Bigger than

D. None of these

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4

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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4

In an internal combustion engine, the process of removing the burnt gases from the combustion chamber of the engine cylinder is known as

A. Scavenging

B. Detonation

C. Supercharging

D. Polymerisation

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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 increase in intake temperature of internal combustion engines will _________ efficiency.

A. Have no effect on

B. Increase

C. Decrease

D. None of these

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4

A heat engine utilises the

A. Calorific value of oil

B. Low heat value of

C. High heat value of oil

D. Mean heat value of oil

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4

The reference fuels for knock rating of spark ignition engines would include

A. Iso-octane and alpha-methyl naphthalene

B. Normal octane and aniline

C. Isooctane and normal hexane

D. Normal heptane and isooctane