This set of Automobile Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Development of IC Engines”.
1. In a Otto cycle engine, combustion occurs at __________
a) Constant pressure
b) Constant temperature
c) Constant volume
d) Constant heat
View Answer
Explanation: Combustion process in an Otto cycle engine occurs at constant volume. Otto cycle has two isentropic processes and two constant volume processes. This cycle is mostly used for petrol engines.
2. In a Diesel cycle engine, combustion occurs at _________
a) Constant pressure
b) Constant temperature
c) Constant volume
d) Constant heat
View Answer
Explanation: Combustion in a Diesel cycle engine occurs at constant pressure.
3. Heat rejection in diesel cycle is at _________
a) Constant pressure
b) Constant volume
c) Constant temperature
d) None of the mentioned
View Answer
Explanation: Heat rejection in diesel cycle occurs at constant volume.
4. In a four stroke ic engine, how many strokes are covered for one complete crankshaft revolution?
a) 4
b) 2
c) 1
d) 0.5
View Answer
Explanation: For a 4 stroke engine, piston covers 2 strokes for one complete crankshaft revolution. It takes two rotations of the crankshaft and 4 strokes of piston to complete one cycle.
5. In a 4-stroke ic engine, which of the strokes is considered as working or power stroke?
a) Suction stroke
b) Compression stroke
c) Expansion stroke
d) Exhaust stroke
View Answer
Explanation: There are 4 strokes in a 4-stroke ic engine. These are Suction,compression,expansion and exhaust stroke. Out of these, the expansion stroke is called working or power stroke.
6. The valves of an ic engine are made to open and close slowly to _________
a) Increase the engine efficiency
b) Decrease the fuel consumption
c) Allow engine to cool in the meantime
d) Provide silent operation under high speed conditions
View Answer
Explanation: The valves are made to open and close slowly to provide silent operation under high speed conditions.
7. Which of these is not an assumption made in deriving the formula for air standard of Otto cycle?
a) There is no heat loss during the cycle
b) The compression and expansion are isothermal
c) The heating and cooling strictly take place at constant volume
d) The suction and exhaust take place at atmospheric pressure
View Answer
Explanation: Compression and expansion are assumed strictly adiabatic in a Otto cycle.
8. Higher efficiency in Otto cycle can be achieved by _______
a) Increasing the compression ratio
b) Decreasing the compression ratio
c) Keeping the compression ratio constant
d) Efficiency does not depend on compression ratio
View Answer
Explanation: Higher efficiency can be achieved by increasing the compression ratio.
9. The expansion process in diesel engine is ________
a) Isothermal
b) Adiabatic
c) Isobaric
d) None of the mentioned
View Answer
Explanation: Adiabatic expansion occurs in diesel cycle.
10. In two-stroke cycle engines, what replaces valves of a four-stroke engine?
a) Fins
b) Notches
c) Ports
d) Tubes
View Answer
Explanation: Valves are replaced by ports in two-stroke engines. Two-stroke engine takes two strokes of piston to complete one revolution of the crankshaft. It also completes the cycle in two strokes.
Sanfoundry Global Education & Learning Series – Automobile Engineering.
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