1. The ratio of indicated thermal efficiency to the corresponding air standard cycle
efficiency is called
(a) net efficiency
(b) efficiency ratio (c) relative efficiency
(d) overall efficiency
(e) cycle efficiency.
Ans: c
2. If the intake air temperature of I.C. engine increases, its volumetric efficiency will
(a) increase
(b) decrease
(c) remain same
(d) unpredictable
(e) depend on other factors.
Ans: b
3. An engine indicator is used to determine the following
(a) speed
(b) temperature
(c) volume of cylinder
(d) m.e.p. and I.H.P.
(e) BHP.
Ans: d
4. The thermal efficiency of a diesel cycle having fixed compression ratio, with increase in
cut-off ratio will
(a) increase
(b) decrease
(c) be independent
(d) may increase or decrease depending on other factors (e) none of the above.
Ans: b
5. The output of a diesel engine can be increased without increasing the engine revolution or
size in following way
(a) feeding more fuel
(b) increasing flywheel size
(c) heating incoming air
(d) scavenging
(e) supercharging.
Ans: e
6. If the temperature of intake air in IC engines is lowered, then its efficiency will
(a) increase
(b) decrease
(c) remain same
(d) increase upto certain limit and then decrease
(e)decrease upto certain limit and then in-crease.
Ans: a
7. Pick up the wrong statement about supercharging
(a) supercharging reduces knocking in diesel engines
(b) there can be limited supercharging in petrol engines because of detonation
(c) supercharging at high altitudes is essential
(d) supercharging results in fuel economy
(e) supercharging is essential in aircraft engines.
Ans: d
8. The reason for supercharging in any engine is to
(a) increase efficiency
(b) increase power
(c) reduce weight and bulk for a given out-put
(d) effect fuel economy
(e) none of the above.
Ans: c
9. Supercharging is essential in
(a) diesel engines
(b) gas turbines
(c) petrol engines
(d) aircraft engines
(e) marine engines.
Ans: d
10. The mean effective pressure obtained from engine indicator indicates the
(a) maximum pressure developed
(b) minimum pressure
(c) instantaneous pressure at any instant
(d) exhaust pressure
(e) average pressure.
Ans: e
11. For the same power developed in I.C. engines, the cheaper system is
(a) naturally aspirated
(b) supercharged
(c) centrifugal pump
(d) turbo charger
(e) none of the above.
Ans: b
12. Installation of supercharger on a four-cycle diesel engine can result in the following
percentage increase in power
(a) upto 25%
(b) upto 35%
(c) upto 50%
(d) upto 75%
(e) upto 100%.
Ans: e
13. A 5 BHP engine running at full load would consume diesel of the order of
(a) 0.3 kg/hr
(b) 1 kg/hr
(c) 3 kg/hr
(d) 5 kg/hr
(e) 10 kg/hr.
Ans: b
14. . The ratio of the volume of charge admitted at N.T.P. to the swept volume of the piston
is called
A. mechanical efficiency
B. overall efficiency
C. volumetric efficiency
D. relative efficiency
15. The frictional power (F.P.) is given by
A. F.P. = B.P. - I.P. B. F.P. = I.P. - B.P.
C. F.P. = B.P./I.P.
D. F.P. = I.P./B.P.
16. A supercharged engine as compared to an ordinary engine
A. requires smaller foundation
B. is lighter
C. consumes less lubricating oil
D. all of these
17. The ratio of the brake power to the indicated power is called
A. mechanical efficiency
B. overall efficiency
C. indicated thermal efficiency
D. volumetric efficiency
18. The ratio of the brake mean effective pressure to the indicated mean effective pressure is
called
A. mechanical efficiency
B. overall efficiency
C. indicated thermal efficiency
D. volumetric efficiency
19. By indicator diagram drawn with the help of an engine indicator _____is obtained.
A. indicated mean effective pressure
B. Brake mean effective pressure
C. Brake power
D.Frictional power
20. The mean effective pressure of a diesel engine having fixed compression ratio will
__________ if cut off ratio decreases.
A. increase
B. decrease C. Remains constant
D. Can’t Say
21. The indicated power for multi-cylinder engine will be same as that of a single cylinder
engine.
A. True
B. False
22. The mechanical efficiency (ηm) of the engine is given by
A.
these
B.
C.
D. none of
23. The brake power is always greater than indicated power.
A. Agree
B. Disagree
24. The operation of forcing additional air under pressure into the engine cylinder is known
as
A. supercharging
B. carburetion
C. turbulence
D. delay
period
25. Supercharging is the process of supplying the intake air to the engine cylinder at a
density ___ the density of the surrounding atmosphere.
A. equal to
B. less than
C. greater than
26. The method of determination of indicated power of a multi cylinder spark ignition engine
is by the use of
A. Morse test
B. prony brake test
C. motoring test
D. heat balance test
27. The power actually developed by the engine cylinder of an I.C. engine is known as
A. theoretical power B. actual power
C. indicated power D. none of these
28. The ratio of the work obtained at the crankshaft in a given time to the energy supplied
during the same time is called
A. mechanical efficiency
B. Brake thermal efficiency
C. indicated thermal efficiency
D. volumetric efficiency
29. The ratio of the indicated thermal efficiency to the air standard efficiency is known as
A. mechanical efficiency
B. overall efficiency
C. volumetric efficiency
D. relative efficiency
30. The brake power is the power available
A. in the engine cylinder
B. at the crank shaft
C. at the crank pin
D. none of these
31. The relative efficiency of an I.C. engine is the ratio of the indicated thermal efficiency to
_______.
A. Air-Standard efficiency
B. Brake thermal efficiency
C. Mechanical efficiency
D. Mechanical efficiency
32. Which one of the following engines will have heavier flywheel than the remaining ones?
A. 30 kW four-stroke petrol engine running at 1500 r.p.m
B. 30 kW two-stroke petrol engine running at 1500 r.p.m.
C. 30 kW two-stroke diesel engine running at 750 r.p.m.
D. 30 kW four-stroke diesel engine running at 750 r.p.m.
33. 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)
A.
B.
C.
D. all of these
34. The ratio of the volume of charge admitted at N.T.P. to the swept volume of the piston
is called
A. mechanical efficiency
B. overall efficiency
C. volumetric efficiency
D. relative efficiency
35. The brake power of a diesel engine, keeping other parameters constant, can be increased
by
A. decreasing the density of intake air
B. increasing the temperature of intake air
C. increasing the pressure of intake air
D. decreasing the pressure of intake air
36. The correct sequence of the decreasing order of brake thermal efficiency of the three
given basic types of engines is
A. four stroke C.I. engine, four stroke S.I. engine, two stroke S.I. engine
B. four stroke S.I. engine, four stroke C.I. engine, two stroke S.I. engine
C. four stroke C.I. engine, two stroke S.I. engine, four stroke S.I. engine
D. two stroke S.I. engine, four stroke S.I. engine, four stroke C.I. engine
37. The increase in intake temperature of internal combustion engines will __________
efficiency.
A. have no effect on B. increase
C. decrease
38. The operation of forcing additional air under pressure into the engine cylinder is known
as
A. supercharging
B. carburetion
C. turbulence
D. delay
period
39. The thermal efficiency of a petrol engine is __________ as compared to diesel engine.
A. same
B. less
C. more
40. Supercharging is the process of supplying the intake air to the engine cylinder at a
density __________ the density of the surrounding atmosphere.
A. equal to
B. less than
C. greater than
41. The method of determination of indicated power of a multi cylinder spark ignition engine
is by the use of
A. Morse test
B. prony brake test C. motoring test
D. heat balance test
42. The power actually developed by the engine cylinder of an I.C. engine is known as
A. theoretical power B. actual power
C. indicated power D. none of these
43. The ratio of the indicated thermal efficiency to the air standard efficiency is known as
A. mechanical efficiency
B. overall efficiency
C. volumetric efficiency
D. relative efficiency
44. The brake power is the power available
A. in the engine cylinder
B. at the crank shaft
C. at the crank pin
D. none of
these
45. If the compression ratio in I.C. engine increases, then its thermal efficiency will
A. decrease
B. increase
C. remain same
46. The relative efficiency of an I.C. engine is the ratio of the indicated thermal efficiency to
the air standard efficiency.
A. Correct
B. Incorrect
47. The volumetric efficiency ofa well designed engine may be
A. 30 to 40%
B. 40 to 60%
C. 60 to 70%
D. 75 to 90%
48. 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)
A.
B.
C.
D. all of these
49. The brake power of a diesel engine, keeping other parameters constant, can be increased
by
A. decreasing the density of intake air
B. increasing the temperature of intake air
C. increasing the pressure of intake air
D. decreasing the pressure of intake air
50. The thermal efficiency of a standard Otto cycle for a compression ratio of 5.5 will be
A. 25%
B. 50%
C. 70%
D. 100%
51. Morse test is conducted on IC engine to determine
(a) Volumetric efficiency of multi-cylinder engines
(b) Thermal efficiency of two-stroke engines
(c) Mechanical efficiency of multi-cylinder engines
(d) Brake power produced by individual cylinders
52. Motoring test is carried out on an IC engine to determine
(a) BP
(b) IP
(c) FP
(d) Fuel consumption at full load
53. Morse test is conducted on the engine to calculate the mechanical efficiency of
(a) Single cylinder SI engine
(b) Single cylinder CI engine
(c) Multi-cylinder engines
(d) Only on two stroke engines
54. An I.C engine is tested
(a) To conform the data used in design whose validity is dough full
(b) To determine the information that cannot be determined by calculation
(c) To ensure satisfactory performance of the engine
(d) All the above
Ans: d