250+ TOP MCQs on Actual Cycle and Answers

IC Engines Multiple Choice Questions on “Actual Cycle”.

1. Time loss factor in Actual Cycle is due to ____________
a) progressive combustion
b) heat loss through cylinder walls
c) gas leakage
d) friction
Answer: a
Clarification: None.

2. If the spark timing is at TDC, the work is ____________
a) more
b) less
c) equal
d) none of the mentioned
Answer: b
Clarification: If the spark timing is at TDC, the work is less as the peak pressure is low.

3. When the spark is advanced, the work output is less as ____________
a) the peak pressure is low
b) the peak temperature is low
c) additional work is required to compress the burning gas
d) frictional losses increase
Answer: c
Clarification: When the spark is advanced, the work output is less as additional work is required to compress the burning gas.

4. Optimum spark timing gives ____________
a) higher mean effective pressure
b) higher efficiency
c) higher mean effective pressure and higher efficiency
d) none of the mentioned
Answer: c
Clarification: None.

5. The major loss in a S.I. engine is due to ____________
a) exhaust blow down
b) pumping
c) incomplete combustion
d) variation in specific heat and chemical equilibrium
Answer: d
Clarification: The major loss in a S.I. engine is due to variation in specific heat and chemical equilibrium while the major loss in a C.I. engine is loss due to incomplete combustion.

6. What is the major loss in a C.I. engine?
a) direct heat loss
b) loss due to incomplete combustion
c) rubbing friction loss
d) pumping loss
Answer: b
Clarification: None.

7. In an actual S.I engine the pumping loss with respect to speed ____________
a) increases
b) decreases
c) remains same
d) none of the mentioned
Answer: b
Clarification: None.

8. The volumetric efficiency is affected by ____________
a) the exhaust gas in the clearance volume
b) the design of intake and exhaust valve
c) valve timing
d) all of the mentioned
Answer: d
Clarification: None.

9. In petrol engine the actual pressure developed compared to the predicted maximum pressure is?
a) 90%
b) 70%
c) 50%
d) 25%
Answer: c
Clarification: In petrol engine the actual pressure developed compared to the predicted maximum pressure is 50% while energy released in actual cycle is about 90% of the fuel input.

10. Energy released in actual cycle is about _____________ of the fuel input.
a) 90%
b) 70%
c) 50%
d) 25%
Answer: a
Clarification: None.