APPLIED THERMODYNAMICS
UNIT 1
1. The Otto cycle is the
a) air standard cycle of CI engine
b) air standard cycle of SI engine
c) vapour power cycle of CI engine
d) vapour power cycle of SI engine
ANS – B
2. In a four-stroke internal combustion engine,
a) the piston does four complete strokes within cylinder
b) for each cycle, the crankshaft completes two revolutions
c) both of the mentioned
d) none of the mentioned
ANS- C
3. The correct sequence of strokes in a four-stroke SI engine is
a) intake->compression->exhaust->expansion
b) intake->expansion->compression->exhaust
c) intake->exhaust->compression->expansion
d) intake->compression->expansion->exhaust
ANS – D
4. The spark plug fires shortly before the ____ stroke.
a) compression
b) expansion
c) intake
d) exhaust
ANS – B
5. The pressure in cylinder is ____ the atmospheric value during exhaust stroke and
____ it during intake stroke.
a) above, below
b) below, above
c) equal to, equal to
d) equal to, above
ANS – A
6. In a two-stroke engine, the four functions performed in SI engine are done in
which two strokes?
a) expansion stroke and compression stroke
b) intake stroke and exhaust stroke
c) compression stroke and power stroke
d) compression stroke and expansion stroke
ANS – C
7. In a two-stroke engine,
a) the crankcase is sealed
b) the outward motion of piston is used to pressurize the air-fuel mixture
c) the intake and exhaust valves are replaced by opening in lower part of cylinder
wall
d) all of the mentioned
ANS – D
8. The two-stroke engine is ____ the four-stroke engine.
a) more efficient than
b) less efficient than
c) equally efficient to
d) none of the mentioned
ANS B
9. The two-stroke engine is
a) simple and expensive
b) high power-to-weight ratio
c) low power-to-volume ratio
d) all of the mentioned
ANS – B
10. Which of the following statement is true?
a) efficiency of air standard cycle is a function of compression ratio and
temperature levels
b) higher the compression ratio, higher will be the efficiency
c) efficiency is dependent on the temperature levels at which the cycle operates
d) all of the mentioned
ANS – B
11. In SI engines,
a) air-fuel mixture is compressed
b) compression ratio is limited
c) both of the mentioned
d) none of the mentioned
ANS – C
12. In CI engines,
a) during compression stroke, only air is compressed
b) compression ratios can be much higher
c) both of the mentioned
d) none of the mentioned
ANS – C
13. The correct sequence of processes in CI engine is
a) intake->fuel injection and combustion->compression->expansion->exhaust
b) intake->compression->fuel injection and combustion->expansion->exhaust
c) intake->compression->expansion->fuel injection and combustion->exhaust
d) intake->compression->exhaust->fuel injection and combustion->expansion
ANS – B
14. The processes in CI engine cycle is completed in ____ strokes of piston and
____ revolutions of crankshaft.
a) four, four
b) two, two
c) two, four
d) four, two
ANS – D
15. The Diesel cycle consists of
a) two reversible isotherms and two reversible isobars
b) one reversible isochore and two reversible adiabatics and one reversible
isobar
c) one reversible isotherm and two reversible isochores and one reversible isobar
d) two reversible isobars and two reversible adiabatics
ANS – B
16. The efficiency of Diesel cycle is ____ the efficiency of Otto cycle.
a) less than
b) greater than
c) equal to
d) none of the mentioned
ANS – A
17. . In Dual cycle,
a) all the heat is added at constant volume
b) all the heat is added at constant pressure
c) some heat is added at constant volume and remaining at constant pressure
d) none of the mentioned
ANS – C
18. Detonation in SI engine is
a) noisy and destructive combustion phenomenon
b) limits the compression ratio
c) it depends on engine design and fuel
d) all of the mentioned
ANS – D
19. The premature ignition of fuel is called ____
a) engine knock
b) auto-ignition
c) detonation
d) all of the mentioned
ANS – B
20. The auto-ignition
a) reduces performance of engine
b) can cause damage to engine
c) sets upper limit to compression ratios used in SI engines
d) all of the mentioned
ANS – D
21. For a given compression raise, the highest efficiency can be obtained by using
a) triatomic gases
b) diatomic gases
c) monoatomic gases
d) all of the mentioned
ANS –C
22. . ɣ ____ with temperature.
a) increases
b) decreases
c) remains constant
d) none of the mentioned
ANS – B
