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4

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

Correct Answer :

D. All of the above


Related Questions

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The reflectivity depends upon

A. Geometry of the reflector

B. Energy of neutrons

C. Properties of the reflector

D. All of these

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4

For maximum power generation, the air fuel ratio for a petrol engine for vehicles, is of the order of

A. 9 : 1

B. 12 : 1

C. 15 : 1

D. 18 : 1

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4

When crude oil is heated, then which of the following hydrocarbon is given off first?

A. Kerosene

B. Gasoline

C. Paraffin

D. Natural gas

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4

The _________ engines can work on very lean mixture of fuel.

A. Spark ignition

B. Compression ignition

C. Both (A) and (B)

D. None of these

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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

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

Antiknock for compression ignition engines is

A. Napthene

B. Tetra ethyl lead

C. Amyl nitrate

D. Hexadecane

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4

If the compression ratio in I.C. engine increases, then its thermal efficiency will

A. Decrease

B. Increase

C. Remain same

D. None of these

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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

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

The injection pressure in a diesel engine is about

A. 10 bar

B. 100 bar

C. 150 bar

D. 500 bar

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4

High speed compression engines operate on

A. Otto cycle

B. Diesel cycle

C. Dual combustion cycle

D. All of these

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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

Morse test is used to determine the I.P. of a

A. Single cylinder petrol engine

B. Four stroke engine

C. Single cylinder diesel engine

D. Multi cylinder engine

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4

Which of the following is not an interns combustion engine?

A. 2-stroke petrol engine

B. 4-stroke petrol engine

C. Diesel engine

D. Steam turbine

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4

Most high speed compression engines operate on

A. Diesel cycle

B. Otto cycle

C. Dual combustion cycle

D. Special type of air cycle

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4

The ignition of the charge by some hot surface within the engine before the passage of spark is called

A. Pre-ignition

B. Detonation

C. Ignition delay

D. Auto-ignition

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4

The fuel valve in a four stroke cycle diesel engine

A. Opens at 15° after top dead centre and closes at 20° before bottom dead centre

B. Opens at 15° before top dead centre and closes at 20° after top dead centre

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

D. May open and close anywhere

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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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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

A diesel 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

A petrol engine, during suction stroke draws

A. Air only

B. Petrol only

C. A mixture of petrol and air

D. None of these

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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

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

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

Compression loss in I.C engines occurs due to

A. Leaking piston rings

B. Use of thick head gasket

C. Clogged air inlet slots

D. All of the above

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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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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

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

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