Internal Combustion Engines (I.C. Engines) | Set 1
1. Advantage of reciprocating IC engines over steam turbine is
Correct : D. all of the above
2. The intake charge in a diesel engine consists of
Correct : A. air alone
3. Engines of different cylinder dimensions, power and speed can be compared on the basis of
Correct : C. mean effective pressure
4. Disadvantages of reciprocating IC engine are
Correct : D. all of the above
5. Gudgeon pin forms the link between
Correct : B. piston and small end of connecting rod
6. In a four-stroke IC engine cam shaft rotates at
Correct : C. halt the speed of crankshaft
7. Thermal efficiency of CI engine is higher than that of SI engine due
Correct : B. higher compression ratio
8. SI engines are of
Correct : D. all of the above
9. Compression ratio in diesel engines is of the order of
Correct : D. 14-20
10. Main advantage of a two-stroke engine over four-stroke engine is
Correct : D. all of the above
11. Engines used for ships are normally
Correct : B. two-stroke CI engines of very high power
12. If L is the stroke and N is the rpm, mean piston speed of two-stroke engine
Correct : C. 2LN
13. The volumetric efficiency of the SI engine is comparatively
Correct : A. lower than CI engine
14. Brake specific fuel consumption is defined as
Correct : D. fuel consumption per brake power hour
15. Engine can be fired with
Correct : D. any of the above fuels
16. A two-stroke engine can be identified by
Correct : C. absence of valves
17. Advantage of two-stroke engine is
Correct : D. all of the above
18. Charge pressure at the inlet port of a two-stroke engine is
Correct : D. higher than atmospheric
19. The most perfect method of scavenging is
Correct : B. uniflow scavenging
20. Two-stroke SI engines suffer from
Correct : A. fuel loss
21. At the same speed two-stroke engine of the same size as a four-stroke engine will develop
Correct : C. twice the power
22. Two wheelers without deflector type piston use
Correct : D. cross scavenging
23. Crankcase scavenged engines have delivery ratio of
Correct : C. equal to 1
24. The working cycle in case of four stroke engine is completed in following number of revolutions of crankshaft
Correct : C. 2
25. In a diesel engine, the fuel is ignited by
Correct : C. heat resulting from compressing air that is supplied for combustion
26. Scavenging air in diesel engine means
Correct : D. air used for forcing burnt gases out of engine's cylinder during the exhaust period
27. Does the supply of scavenging air at a density greater than that of atmosphere mean engine is supercharged?
Correct : B. no
28. The ratio of indicated thermal efficiency to the corresponding air standard cycle efficiency is
called
Correct : C. relative efficiency
29. Compression ratio of LC. Engines is
Correct : A. the ratio of volumes of air in cylinder before compression stroke and after compression stroke
30. A perfect engine works on the Carnot cycle between 727 °C and 227°C. The efficiency of the engine is
Correct : A. 0.5
31. The air standard Otto cycle consists of
Correct : A. two constant volume and two isentropic processes
32. In air standard Diesel cycle at fixed r and fixed n
Correct : B. ƞthermal decreases with increase in heat addition and cut-off ratio
33. Mean effective pressure of Otto cycle is
Correct : B. directly proportional to pressure ratio
34. For a given compression ratio the work output of Otto cycle is
Correct : A. increases with Increase in r
35. For a given value of r, efficiency of Otto cycle
Correct : B. increases with compression ratio
36. For dual combustion cycle for fixed value of heat addition and compression ratio
Correct : A. mep wil be greater with increase in rp, and decrease in rc
37. The normal range of, compression ratio for Otto cycle is
Correct : A. 6 to 10
38. The normal range of compression ratio for Diesel cycle is
Correct : C. 15 to 20
39. For the same compression ratio and heat addition
Correct : C. ƞOtto> ƞDual > ƞDiesel
40. for the same compression ratio and heat rejection,
Correct : A. ƞOtto> ƞDual > ƞDiesel
41. When the engines are built to withstand the sane thermal and mechanical stresses
Correct : A. ƞDiesel > ƞDual > ƞOtto
42. For the same peak pressure and heat input
Correct : C. ƞDiesel > ƞDual > ƞOtto
43. For the same peak pressure and work output
Correct : D. ƞDiesel > ƞDual > ƞOtto
44. Brayton cycle is used in
Correct : B. gas turbines
45. The actual efficiency of a good engine is about _______of the estimated fuel-air cycle
efficiency.
Correct : B. 85%
46. With dissociation peak temperature is obtained
Correct : C. when the mixture is slightly rich
47. With dissociation the exhaust gas temperature
Correct : A. decreases
48. Fuel-air ratio affects maximum power output of the engine due to
Correct : C. both (a) and (b)
49. Mean effective pressure at a given compression ratio is maximum when the air-fuel ratio is
Correct : B. lower than stoichiometric
50. For a compressor process with variable specific heat the peak temperature and pressure are
_______compared to constant specific heat
Correct : A. lower
51. Dissociation can be considered as
Correct : D. all of the above
52. Time loss factor in actual cycle is due to
Correct : A. Progressive combustion
53. The major loss in a SI engine is due to
Correct : D. variation in specific heat and chemical equilibrium
54. Fuel-air cycle efficiency is less than air-standard cycle efficiency by an amount equal to
Correct : C. loss due to specific heat variation and chemical equilibrium
55. The major loss in a CI engine is
Correct : B. loss due to incomplete combustion
56. The ratio of the actual efficiency and the fuel-air cycle efficiency for CI engines is about
Correct : D. 0.6-0.8
57. In an actual SI engine the pumping loss with respect to speed
Correct : B. Increases
58. The volumetric efficiency is affected by
Correct : D. all of the above
59. The air standard efficiency of an Otto cycle compared to diesel cycle for the given compression ratio is
Correct : C. more
60. In a typical medium speed, 4-stroke cycle diesel engine
Correct : A. fuel injection starts at 10° before to dead center and ends at 20° after tor dead center
61. The amount of heat liberated by complete combustion of unit quantity of fuel is known as
________
Correct : C. Calorific value
62. The calorific value of gaseous fuels is expressed in terms of
Correct : D. D. kcal/m3
63. What is the significance of calorific value?
Correct : A. Helps in deciding which fuel is good
64. Which gas has the highest calorific value among given option?
Correct : C. Hydrogen
65. Which calorimeter is used to find calorific values of solid and liquid fuels?
Correct : B. Bomb calorimeter
66. Which calorimeter is used to find calorific values of gaseous fuels?
Correct : B. Junker calorimeter
67. What is the factor on which, difference between the two heating values of fuel depends on?
Correct : C. Chemical composition
68. The Bomb calorimeter is used to determine the calorific value of:
Correct : A. solids and liquid fuels
69. If the intake air temperature of I.C. engine increases, its efficiency will
Correct : B. decrease
70. All heat engines utilize
Correct : A. low heat value of oil
71. An engine indicator is used to determine the following
Correct : D. m.e.p. and I.H.P.
72. Fuel oil consumption guarantees for I .C. engine are usually based on
Correct : B. high heat value of oil
73. Combustion in compression ignition engines is
Correct : B. heterogeneous
74. The air requirement of a petrol engine during starting compared to theoretical required for
complete combustion is
Correct : B. loss
75. Diesel fuel, compared to petrol is
Correct : C. more difficult to ignite
76. When crude oil is heated, then which of the following hydrocarbon is given off first.
Correct : D. natural gas.
77. The rating of a diesel engine, with increase in air-intlet temperature, will
Correct : B. decrease linearly
78. A 75 cc engine has following parameter as 75 cc
Correct : C. swept volume
79. A heat engine utilises the
Correct : C. high heat value of oil
80. Gaseous-fuel guarantees are based on
Correct : B. low heat value of oil
81. Fuel consumption of diesel engines is not guaranteed at one quarter load because at such
low loads
Correct : C. the small difference in cooling water temperature or in internal friction has a disproportionate effect
82. Polymerisation is a chemical process in which molecules of a compound become
Correct : A. larger
83. Which of the following is the lightest and most volatile liquid fuel
Correct : D. gasoline
84. The theoretically correct air fuel ratio for petrol engine is of the order of
Correct : D. 15 : 1
85. Air fuel ratio for idling speed of a petrol engine is approximately
Correct : C. 10:1
86. Air fuel ratio at which a petrol engine can not work is
Correct : D. 20 : 1 and less
87. Advantage of gaseous fuel is that
Correct : B. it can mix easily with air
88. Paraffins are in general represented by
Correct : C. CnH2n+2
89. Paraffins have molecular structure of
Correct : A. chain saturated
90. Olefins are represented by the formula
Correct : A. CnH2n
91. Hydrocarbons are decomposed into smaller hydrocarbons by
Correct : C. cracking
92. The molecular structure of the straight-run gasoline is changed by
Correct : B. reforming
93. For SI engines fuels most preferred are
Correct : A. aromatics
94. For CI engine fuels most preferred are
Correct : B. paraffins
95. Octane number of iso-octane is
Correct : D. 100
96. Ignition quality of diesel fuel is indicated by its
Correct : B. cetane number
97. Flash point of fuel oil is
Correct : A. minimum temperature to which1 oil is heated in order to give off inflammable vapours in Sufficient quantity to ignite momentarily when brought in contact with a flame
98. Gasohol is a mixture of
Correct : B. 10% ethanol +90% gasoline
99. Stoichiometric air-fuel ratio of petrol is roughly