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Current Affairs January 2024

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4

A higher compression ratio causes

A. Pre-ignition

B. Increase in detonation

C. Acceleration in the rate of combustion

D. Any one of these

Correct Answer :

D. Any one of these


Related Questions

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4

The ratio of the work obtained at the crankshaft in a given time to the energy supplied during the same time is called

A. Mechanical efficiency

B. Overall efficiency

C. Indicated thermal efficiency

D. Volumetric efficiency

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4

In a four stroke cycle petrol engine, the charge is ignited at

A. 30° before top dead centre

B. 30° after top dead centre

C. 30° before bottom dead centre

D. 30° after bottom dead centre

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4

Combustion in compression ignition engines is

A. Homogeneous

B. Heterogeneous

C. Both (A) and (B)

D. Laminar

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4

The operation of forcing additional air under pressure in the engine cylinder is known as

A. Scavenging

B. Turbulence

C. Supercharging

D. Pre-ignition

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4

The inlet value of a four stroke cycle I.C engine remains open for nearly

A. 180°

B. 125°

C. 235°

D. 200°

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4

Gaseous fuel guarantees are based on

A. Calorific value of oil

B. Low heat value of oil

C. High heat value of oil

D. Mean heat value of oil

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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

Antiknock for compression ignition engines is

A. Napthene

B. Tetra ethyl lead

C. Amyl nitrate

D. Hexadecane

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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

In a naturally aspirated diesel engine, the air is supplied by

A. A supercharger

B. A centrifugal blower

C. A vacuum chamber

D. An injection tube

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4

The power actually developed by the engine cylinder of an I.C. engine is known as

A. Theoretical power

B. Actual power

C. Indicated power

D. None of these

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4

In petrol engines, the delay period is of the order of

A. 0.001 second

B. 0.002 second

C. 0.003 second

D. 0.004 second

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4

In a four stroke cycle engine, the sequence of operations is

A. Suction, compression, expansion and exhaust

B. Suction, expansion, compression and exhaust

C. Expansion, compression, suction and exhaust

D. Compression, expansion, suction and exhaust

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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 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

A petrol 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

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

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 reason for supercharging in any engine is to

A. Increase efficiency

B. Increase power

C. Reduce weight and bulk for a given output

D. Effect fuel economy

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4

The increase of cooling water temperature in petrol engine will __________ the knocking tendency.

A. Not effect

B. Decrease

C. Increase

D. None of these

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4

In compression ignition engines, swirl denotes a

A. Haphazard motion of the gases in the chamber

B. Rotary motion of the gases in the chamber

C. Radial motion of the gases in the chamber

D. None of the above

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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

Which of the following does not relate to a compression ignition engine?

A. Fuel pump

B. Fuel injector

C. Governor

D. Carburettor

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4

The spark ignition engines are governed by

A. Hit and miss governing

B. Qualitative governing

C. Quantitative governing

D. Combination of (B) and (C)

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4

The thermal efficiency of a petrol engine is _________ as compared to diesel engine.

A. Same

B. Less

C. More

D. None of these

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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

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

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

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

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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