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4

In a typical medium speed 4-stroke cycle diesel engine the inlet valve

A. Opens at 20° before top dead center and closes at 35° after the bottom dead center

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

C. Opens at 10° after top dead center and closes 20° before the bottom dead center

D. May open or close anywhere

Correct Answer :

A. Opens at 20° before top dead center and closes at 35° after the bottom dead center


Related Questions

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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 statement is wrong?

A. In compression ignition engines, detonation occurs near the beginning of combustion.

B. Since the fuel, in compression ignition engines, is injected at the end of compression stroke, therefore, there will be no pre-ignition.

C. To eliminate knock in compression ignition engines, we want to achieve auto-ignition not early and desire a long delay period.

D. In compression ignition engines, because of heterogeneous mixture, the rate of pressure rise is comparatively lower.

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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

Does the supply of scavenging air at a density greater than that of atmosphere mean engine is supercharged?

A. Yes

B. No

C. To some extent

D. Unpredictable

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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

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

The correct mixture strength (by weight) for petrol is about

A. 14.6 : 1

B. 18.5 : 1

C. 20.4 : 1

D. 22.6 : 1

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4

The thermal efficiency of diesel engines on weak mixtures is

A. Unaffected

B. Lower

C. Higher

D. Dependent on other factors

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4

In the crankcase method of scavenging, the air pressure is produced by

A. Supercharger

B. Centrifugal pump

C. Natural aspirator

D. Movement of engine piston

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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

The fuel in diesel engine is normally injected at pressure of

A. 5-10 kg/cm²

B. 20-25 kg/cm²

C. 60-80 kg/cm²

D. 90-130 kg/cm²

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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

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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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

The mean effective pressure obtained from engine indicator indicates the

A. Maximum pressure developed

B. Minimum pressure

C. Instantaneous pressure at any instant

D. Average pressure

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4

In a typical medium speed 4-stroke cycle diesel engine

A. Compression starts at 35° after bottom dead center and ends at top dead center

B. Compression starts at bottom dead center and ends at top dead center

C. Compression starts at 10° before bottom dead center and, ends just before top dead center

D. May start and end anywhere

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4

The function of a distributor in a coil ignition system of I.C. engines is

A. To distribute spark

B. To distribute power

C. To distribute current

D. To time the spark

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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

Which one of the following event would reduce volumetric efficiency of a vertical compression ignition engine?

A. Inlet valve closing after bottom dead centre

B. Inlet valve closing before bottom dead centre

C. Inlet valve opening before top dead centre

D. Exhaust valve closing after top dead centre

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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 pressure and temperature at the end of compression stroke in a petrol engine are of the order of

A. 4-6 kg/cm² and 200-250°C

B. 6-12 kg/cm² and 250-350°C

C. 12-20 kg/cm² and 350-450°C

D. 20-30 kg/cm² and 450-500°C

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4

The air-fuel ratio in petrol engines is controlled by

A. Controlling valve opening/closing

B. Governing

C. Injection

D. Carburetion

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4

The knock in diesel engine occurs due to

A. Instantaneous and rapid burning of the first part of the charge

B. Instantaneous auto ignition of last part of charge

C. Delayed burning of the first part of the charge

D. Reduction of delay period

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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

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

Pour point of fuel oil is the

A. Minimum temperature to which oil is heated in order to give off inflammable vapours in sufficient quantity to ignite momentarily when brought in contact with a flame

B. Temperature at which it solidifies or congeals

C. It catches fire without external aid

D. Indicated by 90% distillation temperature i.e., when 90% of sample oil has distilled off

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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

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 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

A mixture containing 65% of iso-octane and 35% of normal heptane will have

A. Cetane number 65

B. Octane number 65

C. Cetane number 35

D. Octane number 35