4

6 kg/cm

12 kg/cm

20 kg/cm

35 kg/cm

D. 35 kg/cm

4

Fuel pump

Injector

Carburettor

None of these

4

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

Mechanical efficiency

Overall efficiency

Indicated thermal efficiency

Volumetric efficiency

4

# The _________ engines can work on very lean mixture of fuel.

Spark ignition

Compression ignition

Both (A) and (B)

None of these

4

10 bar

100 bar

150 bar

500 bar

4

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

Same

More

Less

Less or more depending on operating conditions

4

1/2

1

2

4

4

# The method of determination of indicated power of a multi cylinder spark ignition engine is by the use of

Morse test

Prony brake test

Motoring test

Heat balance test

4

Benzene

Iso-octane

Normal heptane

Alcohol

4

0.15 kg

0.2 kg

0.25 kg

0.3 kg

4

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

A supercharger

A centrifugal blower

A vacuum chamber

An injection tube

4

# In a typical medium speed 4-stroke cycle diesel engine

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

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

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

May start and end anywhere

4

# The brake power (B.P.) of the engine is given by (where W = Brake load or dead load in newtons, l = Length of arm in metres, N = Speed of engine in r.p.m., S = Spring balance reading in newtons, D = Dia. of brake drum in metres, and d = Dia. of rope in metres)

B.P = (Wl × 2πN)/60 watts

B.P = [(W - S) πDN]/60 watts

B.P = [(W - S) π (D + d) N]/60 watts

All of these

4

# Pour point of fuel oil is the

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

Temperature at which it solidifies or congeals

It catches fire without external aid

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

4

1 m3

5 m3

56 m3

910 m3

4

Half

Same

Double

Four times

4

# Compression ratio of I.C. Engines is

The ratio of volumes of air in cylinder before compression stroke and after compression stroke

Volume displaced by piston per stroke and clearance volume in cylinder

Ratio of pressure after compression and before compression

Swept volume/cylinder volume

4

Not effect

Decrease

Increase

None of these

4

SEA 30

SAE 50

SAE 70

SAE 80

4

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

Mechanical efficiency

Overall efficiency

Volumetric efficiency

Relative efficiency

4

# By higher octane number of spark ignition fuel, it is meant that the fuel has

Higher heating value

Higher flash point

Lower volatility

Longer ignition delay

4

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

Beginning of suction stroke

End of suction stroke

End of compression stroke

None of these

4

Yes

No

To some extent

Unpredictable

4

# In compression ignition engines, swirl denotes a

Haphazard motion of the gases in the chamber

Rotary motion of the gases in the chamber

Radial motion of the gases in the chamber

None of the above

4

Alcohol

Water

None of these

4

Half

Same

Double

Four times

4

# Which of the following statement is correct?

Compression ratio for petrol engines varies from 6 to 10

Higher compression ratio in diesel engines results in higher pressures

Petrol engines work on Otto cycle

All of the above

4

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

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

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

May open or close anywhere

4

One valve

Two valves

Three valves

Four valves

4

# The minimum cranking speed in case of petrol engine is about

Half the operating speed

One fourth of operating speed

250 - 300 rpm

60 - 80 rpm