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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

Correct Answer :

C. Dual combustion cycle


Related Questions

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4

The sensing element in the control system of nuclear reactors measures the _________ of the neutron flux in the reactor.

A. Temperature

B. Volume

C. Density

D. None of these

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4

The ignition quality of diesel oil is expressed by

A. Cetane number

B. Octane number

C. Calorific value

D. None of these

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4

In a coil ignition system of petrol engines, a condenser is connected across the contact breaker in order to

A. Prevent sparking across the gap between the points

B. Cause more rapid break of the primary current, giving a higher voltage in the secondary circuit

C. Both (A) and (B)

D. None of the above

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4

Volatility of diesel fuel oil is

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

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 octane number of petrol, generally available, is

A. 20 to 40

B. 40 to 60

C. 60 to 80

D. 80 to 100

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4

Engine pistons are usually made of aluminium alloy because it

A. Is lighter

B. Wear is less

C. Absorbs shocks

D. Is stronger

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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 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

Scavenging air in diesel engine means

A. Air used for combustion sent under pressure

B. Forced air for cooling cylinder

C. Burnt air containing products of combustion

D. Air used for forcing burnt gases out of engine's cylinder during the exhaust period

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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 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

If the speed of the engine is increased, the indicated power will

A. Increase

B. Decrease

C. Remain same

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

If the intake air temperature of I.C. engine increases, its efficiency will

A. Increase

B. Decrease

C. Remain same

D. None of these

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4

The process of breaking up or a liquid into fine droplets by spraying is called

A. Vaporisation

B. Carburetion

C. Ionisation

D. Atomisation

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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 actual volume of fresh charge admitted in 4-stroke petrol engine is

A. Equal to stroke volume

B. Equal to stroke volume and clearance volume

C. Less than stroke volume

D. More than stroke volume

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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

Morse test can be conducted for

A. Petrol engines

B. Diesel engines

C. Multi cylinder engines

D. All of these

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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

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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

A diesel engine as compared to petrol engine (both running and rated load) is

A. More efficient

B. Less efficient

C. Equally efficient

D. Other factors will decide it

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4

The thermal efficiency of diesel engines is about

A. 15 %

B. 30 %

C. 50 %

D. 70 %

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4

Which of the following statement is correct regarding petrol engines?

A. A fine fuel spray mixed with air is ignited by the heat of compression which is at a high pressure

B. The fuel supplied to the engine cylinder is mixed with necessary amount of air and the mixture in ignited with the help of a spark plug

C. The fuel is first evaporated after passing through a carburettor and is mixed with air before ignition

D. All of the above

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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

In a four stroke cycle petrol engine, the expansion

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

B. Starts at 30° before top dead centre and ends at 50° before bottom dead centre

C. Starts at 30° after top dead centre and ends at 50° after bottom dead centre

D. May start and end anywhere

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4

In a petrol engine, if diesel is used, then the engine will

A. Not run

B. Run more efficiently

C. Run at high speed

D. Explode

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4

The colour of exhaust from diesel engine is generally

A. White

B. Bluish

C. Black

D. Violet