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Current Affairs January 2024

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4

Which is more viscous lube oil?

A. SEA 30

B. SAE 50

C. SAE 70

D. SAE 80

Correct Answer :

D. SAE 80


Related Questions

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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

Pick up the wrong statement

A. 2-stroke engine can run in any direction

B. In 4-stroke engine, a power stroke is obtained in 4-strokes

C. Thermal efficiency of 4-stroke engine is more due to positive scavenging

D. Petrol engines occupy more space than diesel engines for same power output

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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

The injector nozzle of a compression ignition engine is required to inject fuel at a sufficiently high pressure in order to

A. Inject fuel in a chamber of high pressure at the end of compression stroke

B. Inject fuel at a high velocity to facilitate atomisation

C. Ensure that penetration is not high

D. All of the above

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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 fuels in order of decreasing knock tendency for spark ignition engines are

A. Paraffin, aromatic, napthene

B. Paraffin, napthene, aromatic

C. Napthene, aromatics, paraffin

D. Napthene, paraffin, aromatic

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4

The colour of exhaust from diesel engine is generally

A. White

B. Bluish

C. Black

D. Violet

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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 working pressure and temperature inside the cylinder of an internal combustion engine is _________ as compared to a steam engine.

A. Low

B. Very low

C. High

D. Very high

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4

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 exhaust valve in a four stroke cycle petrol engine

A. Opens at 50° before bottom dead centre and closes at 15° after top dead centre

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

C. Opens at 50° after bottom dead centre and closes at 15° before top dead centre

D. May open and close anywhere

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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

In a typical medium speed 4-stroke cycle diesel engines

A. Exhaust valve opens at 35° before bottom dead centre and closes at 20° after top dead centre

B. Exhaust valve opens at bottom dead centre and closes at top dead centre

C. Exhaust valve opens just after bottom dead centre and closes just before top dead centre

D. May open and close anywhere

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4

The ratio of indicated thermal efficiency to the corresponding air standard cycle efficiency is called

A. Net efficiency

B. Efficiency ratio

C. Relative efficiency

D. Overall efficiency

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4

The knocking tendency in compression ignition engines for a given fuel will be

A. Enhanced by decreasing compression ratio

B. Enhanced by increasing compression ratio

C. Dependent on other factors

D. None of the above

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4

In a four stroke cycle diesel engine, the compression

A. Starts at 40° after bottom dead centre and ends at 10° before top dead centre

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

C. Starts at top dead centre and ends at 40° before bottom dead centre

D. May start and end anywhere

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4

The theoretically correct mixture of air and petrol is

A. 10 : 1

B. 15 : 1

C. 20 : 1

D. 25 : 1

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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

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 specific fuel consumption per B.P. hour for a petrol engine is about

A. 0.2 kg

B. 0.25 kg

C. 0.3 kg

D. 0.35 kg

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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 pressure at the end of compression, in diesel engines, is approximately

A. 10 bar

B. 20 bar

C. 25 bar

D. 35 bar

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4

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

In order to eliminate knocking in compression ignition engines, there should be

A. Short delay period

B. Late auto-ignition

C. Low compression ratio

D. High self ignition temperature of fuel

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4

In petrol engine, using a fixed octane rating fuel and fixed compression ratio, supercharging will _________ the knocking tendency.

A. Not effected

B. Decrease

C. Increase

D. None of these

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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

In a four stroke cycle diesel engine, the inlet valve

A. Opens at 20° before top dead centre and closes at 40° after bottom dead centre

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

Fuel oil consumption guarantees for I .C. engine are usually based on

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 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

Which of the following is false statement? Excess quantities of sulphur in diesel fuel are Objectionable because it may cause the following

A. Piston ring and cylinder wear

B. Formation of hard coating on piston skirts

C. Oil sludge in the engine crank case

D. Detonation