4

# The exhaust valve in a four stroke cycle petrol engine

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

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

May open and close anywhere

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

4

4

Same

Lower

Higher

None of these

4

# As a result of detonation in an I.C. engine, following parameter attains very high value

Peak pressure

Rate of rise of pressure

Rate of rise of temperature

Peak temperature

4

# The fuel valve in a four stroke cycle diesel engine

Opens at 15° after top dead centre and closes at 20° before bottom dead centre

Opens at 15° before top dead centre and closes at 20° after top dead centre

May open and close anywhere

4

Temperature

Volume

Density

None of these

4

# The probability of knocking in diesel engines is increased by

High self ignition temperature

Low volatility

Higher viscosity

All of these

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

# The rating of a diesel engine, with increase in air inlet temperature, will

Increase linearly

Decrease linearly

Increase parabolically

Decrease parabolically

4

# The frictional power (F.P.) is given by

F.P. = B.P. - I.P.

F.P. = I.P. - B.P.

F.P. = B.P./I.P.

F.P. = I.P./B.P.

4

# The mean effective pressure obtained from engine indicator indicates the

Maximum pressure developed

Minimum pressure

Instantaneous pressure at any instant

Average pressure

4

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

Not run

Run more efficiently

Run at high speed

Explode

4

Yes

No

To some extent

Unpredictable

4

Same

Less

More

None of these

4

5-10 kg/cm²

20-25 kg/cm²

60-80 kg/cm²

90-130 kg/cm²

4

# As compared to air standard cycle, in actual working, the effect of variation in specific heats is to

Increase maximum pressure and maximum temperature

Reduce maximum pressure and maximum temperature

Increase maximum pressure and decrease maximum temperature

Decrease maximum pressure and increase maximum temperature

4

15 %

30 %

50 %

70 %

4

Flat

Contoured

Slanted

Depressed

4

Benzene

Iso-octane

Normal heptane

Alcohol

4

# Diesel fuel, compared to petrol is

Less difficult to ignite

Just about the same difficult to ignite

More difficult to ignite

Highly ignitable

4

Pre-ignition

Detonation

Ignition delay

Auto-ignition

4

# All heat engines utilize

Low heat value of oil

High heat value of oil

Net calorific value of oil

Calorific value of fuel

4

Remain same

Decrease

Increase

None of these

4

# The mechanical efficiency (ηm) of the engine is given by

ηm = B.P/I.P

ηm = I.P/B.P

ηm = (B.P × I.P)/100

None of these

4

6 kg/cm

12 kg/cm

20 kg/cm

35 kg/cm

4

180°

125°

235°

200°

4

15 %

30 %

50 %

70 %

4

Cetane number 65

Octane number 65

Cetane number 35

Octane number 35

4

14.6 : 1

18.5 : 1

20.4 : 1

22.6 : 1

4

# If petrol is used in a diesel engine, then

Low power will be produced

Efficiency will be low

Higher knocking will occur

Black smoke will be produced