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4

Which of the following fuel has little tendency towards detonation?

A. Benzene

B. Iso-octane

C. Normal heptane

D. Alcohol

Correct Answer :

B. Iso-octane


Related Questions

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4

The brake power of a diesel engine, keeping other parameters constant, can be increased by

A. Decreasing the density of intake air

B. Increasing the temperature of intake air

C. Increasing the pressure of intake air

D. Decreasing the pressure of intake air

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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

During idling, a petrol engine requires _________ mixture.

A. Lean

B. Rich

C. Chemically correct

D. None of these

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4

Which one of the following engines will have heavier flywheel than the remaining ones?

A. 30 kW four-stroke petrol engine running at 1500 r.p.m.

B. 30 kW two-stroke petrol engine running at 1500 r.p.m.

C. 30 kW two-stroke diesel engine running at 750 r.p.m.

D. 30 kW four-stroke diesel engine running at 750 r.p.m.

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The pressure inside the cylinder is _________ the atmospheric pressure during the exhaust stroke.

A. Equal to

B. Below

C. Above

D. None of these

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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

A two stroke cycle engine gives ________ the number of power strokes as compared to the four stroke cycle engine, at the same engine speed.

A. Half

B. Same

C. Double

D. Four times

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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

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

A. 0

B. 50

C. 100

D. 120

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4

A 75 cc engine has following parameter as 75 cc

A. Fuel tank capacity

B. Lube oil capacity

C. Swept volume

D. Cylinder volume

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4

The specific fuel consumption per BHP hour for diesel engine is approximately

A. 0.15 kg

B. 0.2 kg

C. 0.25 kg

D. 0.3 kg

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4

Which of the following is false statement? Some of the methods used to reduce diesel smoke are as follows

A. Using additives in the fuel

B. Increasing the compression ratio

C. Adherence to proper fuel specification

D. Avoidance of overloading

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4

If the compression ratio of an engine working on Otto cycle is increased from 5 to 7, the percentage increase in efficiency will be

A. 2 %

B. 4 %

C. 8 %

D. 14 %

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4

The thermal efficiency of petrol and gas engines is about

A. 15 %

B. 30 %

C. 50 %

D. 70 %

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4

The term scavenging is generally associated with

A. 2-stroke cycle engines

B. 4-stroke cycle engines

C. Aeroplane engines

D. High efficiency engines

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4

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 knocking tendency in spark ignition engines may be decreased by

A. Controlling the air-fuel mixture

B. Controlling the ignition timing

C. Controlling the exhaust temperature

D. Reducing the compression ratio

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4

The working cycle in case of four stroke engine is completed in following number of revolutions of crankshaft

A. 1/2

B. 1

C. 2

D. 4

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4

Which of the following fuel has little tendency towards detonation?

A. Benzene

B. Iso-octane

C. Normal heptane

D. Alcohol

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4

A diesel engine is _________ as compared to petrol engine, both running at rated load.

A. Equally efficient

B. Less efficient

C. More efficient

D. None of these

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4

It the temperature of intake air in IC engines is lowered, then its efficiency will

A. Increase

B. Decrease

C. Remain same

D. Increase up to certain limit and then decrease

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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

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

The ignition quality of diesel oil is expressed by

A. Cetane number

B. Octane number

C. Calorific value

D. None of these

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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

In a petrol engine, the fuel supplied to the engine cylinder is mixed with required quantity of air and the mixture is ignited with a

A. Fuel pump

B. Fuel injector

C. Spark plug

D. None of these

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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 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

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

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