Home
Current Affairs January 2024

What is the correct answer?

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

Correct Answer :

A. Four stroke C.I. engine, four stroke S.I. engine, two stroke S.I. engine


Related Questions

What is the correct answer?

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

What is the correct answer?

4

In a petrol engine, the mixture has the lowest pressure at the

A. Beginning of suction stroke

B. End of suction stroke

C. End of compression stroke

D. None of these

What is the correct answer?

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

What is the correct answer?

4

The normal heptane (C7H16) is given a rating of ________ octane number.

A. 0

B. 50

C. 100

D. 120

What is the correct answer?

4

Scavenging is usually done to increase

A. Thermal efficiency

B. Speed

C. Power output

D. Fuel consumption

What is the correct answer?

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

What is the correct answer?

4

A supercharged engine as compared to an ordinary engine

A. Requires smaller foundation

B. Is lighter

C. Consumes less lubricating oil

D. All of these

What is the correct answer?

4

In order to mix air and petrol in the required proportion and to supply it to the engine during suction stroke, then _________ is employed.

A. Fuel pump

B. Injector

C. Carburettor

D. None of these

What is the correct answer?

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

What is the correct answer?

4

The pressure at the end of compression, in petrol engines, is approximately

A. 10 bar

B. 20 bar

C. 25 bar

D. 35 bar

What is the correct answer?

4

The reflectivity depends upon

A. Geometry of the reflector

B. Energy of neutrons

C. Properties of the reflector

D. All of these

What is the correct answer?

4

The volumetric efficiency of a well designed engine may be

A. 30 to 40 %

B. 40 to 60 %

C. 60 to 70 %

D. 75 to 90 %

What is the correct answer?

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

What is the correct answer?

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

What is the correct answer?

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

What is the correct answer?

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

What is the correct answer?

4

A stoichiometric air-fuel ratio is

A. Chemically correct mixture

B. Lean mixture

C. Rich mixture for idling

D. Rich mixture for over loads

What is the correct answer?

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

What is the correct answer?

4

The thermal efficiency of a standard Otto cycle for a compression ratio of 5.5 will be

A. 25 %

B. 50 %

C. 70 %

D. 100 %

What is the correct answer?

4

Which of the following statements is correct?

A. All the irreversible engines have same efficiency

B. All the reversible engines have same efficiency

C. Both Rankine and Carnot cycles have same efficiency between same temperature limits

D. All reversible engines working between same temperature limits have same efficiency

What is the correct answer?

4

In petrol engines, advancing of the spark timing will _________ the knocking tendency.

A. Not effect

B. Decrease

C. Increase

D. None of these

What is the correct answer?

4

The ratio of the volume of charge admitted at N.T.P. to the swept volume of the piston is called

A. Mechanical efficiency

B. Overall efficiency

C. Volumetric efficiency

D. Relative efficiency

What is the correct answer?

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

What is the correct answer?

4

The specific fuel consumption of a petrol engine compared to diesel engine of same H.P. is

A. Same

B. More

C. Less

D. Less or more depending on operating conditions

What is the correct answer?

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

What is the correct answer?

4

Diesel as compared to petrol is

A. Highly ignitable

B. More difficult to ignite

C. Less difficult to ignite

D. None of these

What is the correct answer?

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

What is the correct answer?

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

What is the correct answer?

4

A fuel of an octane number rating of 75 matches in knocking intensity as a mixture of

A. 75% iso-octane and 25% normal heptane

B. 75% normal heptane and 25% iso-octane

C. 75% petrol and 25% diesel

D. 75% diesel and 25% petrol

What is the correct answer?

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