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4

In a four stroke cycle petrol engine, the compression

A. Starts at 40° after bottom dead centre and ends at 30° before top dead centre

B. Starts at 40° before bottom dead centre and ends at 30° after bottom dead centre

C. Starts at bottom dead centre and ends at top dead centre

D. May start and end anywhere

Correct Answer :

A. Starts at 40° after bottom dead centre and ends at 30° before top dead centre


Related Questions

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In the opposed piston diesel engine, the combustion chamber is located

A. Above the piston

B. Below the piston

C. Between the pistons

D. There is no such criterion

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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

The following volume of air is required for consuming 1 litre of fuel by a four stroke engine

A. 1 m3

B. 5 m3

C. 56 m3

D. 910 m3

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4

The air standard efficiency of an Otto cycle compared to diesel cycle for the given compression ratio is

A. Same

B. Less

C. More

D. More or less depending on power rating

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Pre-ignition is caused by the spontaneous combustion of the mixture before the end of the compression stroke, and is due to

A. Cylinder walls being too hot

B. Overheated spark plug points

C. Red hot carbon deposits on cylinder walls

D. Any one of these

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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

In a diesel engine, the fuel is ignited by

A. Spark

B. Injected fuel

C. Heat resulting from compressing air that is supplied for combustion

D. Ignition

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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 two reference fuels used for cetane rating are

A. Cetane and iso-octane

B. Cetane and alpha-methyl naphthalene

C. Cetane and normal heptane

D. Cetane and tetra ethyl lead

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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 specific fuel consumption per BH hour for a petrol engine is approximately

A. 0.15 kg

B. 0.2 kg

C. 0.25 kg

D. 0.3 kg

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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

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

Crankcase explosion in I.C. engines usually occurs as

A. First a mild explosion followed by a bi explosion

B. First a big explosion followed by a mil explosion

C. Both mild and big explosions occurs simultaneously

D. Never occurs

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4

A carburettor is used to supply

A. Petrol, air and lubricating oil

B. Air and diesel

C. Petrol and lubricating oil

D. Petrol and air

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4

The correct sequence of the decreasing order of brake thermal efficiency of the three given basic types of engines is

A. Four stroke C.I. engine, four stroke S.I. engine, two stroke S.I. engine

B. Four stroke S.I. engine, four stroke C.I. engine, two stroke S.I. engine

C. Four stroke C.I. engine, two stroke S.I. engine, four stroke S.I. engine

D. Two stroke S.I. engine, four stroke S.I. engine, four stroke C.I. engine

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4

In order to prevent knocking in spark ignition engines, the charge away from the spark plug should have

A. Low density

B. Low temperature

C. Long ignition delay

D. All of these

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4

An engine indicator is used to determine the following

A. Speed

B. Temperature

C. Volume of cylinder

D. m.e.p. and I.H.P.

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The volumetric efficiency of a well designed engine may be

A. 30 to 40 %

B. 40 to 60 %

C. 60 to 70 %

D. 75 to 90 %

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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 ignition quality of petrol is expressed by

A. Cetane number

B. Octane number

C. Calorific value

D. All of these

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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

In case of gas turbines, the gaseous fuel consumption guarantees are based on

A. High heat value

B. Low heat value

C. Net calorific value

D. Calorific value

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4

The air requirement of a petrol engine during starting compared to theoretical air required for complete combustion is

A. More

B. Less

C. Same

D. May be more or less depending on engine capacity

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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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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

By higher octane number of spark ignition fuel, it is meant that the fuel has

A. Higher heating value

B. Higher flash point

C. Lower volatility

D. Longer ignition delay

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4

In diesel engine, the compression ratio in comparison to expansion ratio is

A. Same

B. Less

C. More

D. Variable

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4

The firing order in an I.C. engine depends upon

A. Arrangement of the cylinders

B. Design of crankshaft

C. Number of cylinders

D. All of these

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The delay period in compression ignition engines depends upon

A. Temperature and pressure in the cylinder at the time of injection

B. Nature of the fuel mixture strength

C. Relative velocity between the fuel injection and air turbulence pressure of residual gases

D. All of the above