Quiznetik

Applied Thermodynamics (AT) | Set 4

1. During cold starting problems in winter seasons in india

Correct : B. choke valve is closed

2. Pressure at the throat at fully open position of throttle condition lies in between

Correct : C. 4 to 5 mm hg below atmospheric pressure

3. Throttle valve is placed on which side of venturi

Correct : D. after venturi

4. At high speed of engine and for fully open position of throttle valve.

Correct : A. more air-fuel mixture it send to cylinder.

5. Drawbacks of simple carborator are

Correct : C. both a&b

6. In case of simple carburetor for high speed engines too rich mixture is created because of following reason

Correct : D. too high vacuum at throat

7. In the simple carburetor which of the following modification is necessory for increasing air flow to compenset for rich mixture

Correct : D. all of the above

8. During idling condition of SI engine mixtue is diluted because of exhaust gases presence in cylinder, so fuel is provided in venturi tube

Correct : B. after throttle valve because of suction created at that point

9. Idle adjust in idling arrangement is used mainly to control the

Correct : C. air bleed

10. __________ is the process of preparation of mixture of fuel and air before admission to cylinder.

Correct : B. carburettion

11. Which of the following is not the part of fuel induction system.

Correct : D. spark plug

12. The function of carburettor is,

Correct : D. none of the above

13. The function of carburettor is to control,

Correct : D. none of the above

14. The process of carburettion depends on

Correct : D. all of the above

15. Volatile fuels with heating in intake manifolds will

Correct : D. both a and b

16. Time available in seconds for process of carburettion at about 4000 rpm is about

Correct : A. 0.0075 to 0.01

17. Increased temperature of inlet air, causes volumetric efficency of engine to

Correct : B. decrease

18. A carburettor is used in case of

Correct : B. petrol engines

19. The chemically correct mixture for petrol is approximately

Correct : B. 1970-01-01 15:01:00

20. Mixture requirements at different load and speeds of petrol engine are

Correct : D. all of the above

21. Cruishing range as percentage of designed load refers to

Correct : B. 20 to 75

22. Idling of engine refers to

Correct : A. no load

23. To develop maximum power, mixture supplied is

Correct : A. rich

24. To have minimum specific fuek consumption ot to achieve maximum economy of fuel, mixture supplied is

Correct : C. lean

25. Engine at the time of starting and idling needs mixture which is,

Correct : A. rich

26. At low load running (zero to 20% load of rated power) engine requires mixture which is,

Correct : A. rich

27. During sudden acceleration, engine requires

Correct : A. rich mixture

28. Mixture requirements by the engine part load running ( cruising range) is,

Correct : C. lean

29. A:F ratio needed during maximum power is

Correct : A. 12 to 13.5:1

30. A:F ratio needed for minimum specific fuel consumption of S.I. engine is,

Correct : C. 16.5 to 17.5:1

31. A:F ratio needed at the time of starting and idling is

Correct : A. 11 to 12:1

32. A:F ratio required for low load running in the range of zero to 20% load is,

Correct : A. 12 to 14:1

33. A:F ratio used during part load running cruising range from

Correct : C. 16 to 17.5:1

34. A petrol engine is ____________

Correct : B. quantity governed

35. The tip of main nozzle with reference to petrol level in float chamber is

Correct : B. at higher level

36. During idling of engine of engine, it requires

Correct : D. rich mixture

37. Which of the following is not the requirement of a good carburettor?

Correct : B. prepare non-homogeneous (heterogeneous) mixture

38. Which is not the drawback of a simple carburettor,

Correct : A. it provides required air-fuel ratio at all throttle position

39. A choke in the carburettor is

Correct : A. kept in closed closed position when cold starting the engine

40. During no load (idling) running of engine, the throttle valve is kept slmodt in closed position. A simple carburettor will provide

Correct : C. extreamly lean mixture

41. The idle jet does not supply fuel during

Correct : B. during part load running

42. Which of the following is not the requirement of the carburetor

Correct : B. prepare non homogeneous mixture

43. Which is not drawback of simple carburetor?

Correct : D. none of the above

44. A choke in the carburetor is

Correct : A. kept in closed position when cold starting the engine

45. During no load running of the engine, the throttle valve is kept almost closed. A simple carburetor will provide

Correct : A. rich mixture

46. Compensating devices are provided in carburetor

Correct : B. to supply af ratio always as needed by economy running

47. An emulsion tube or air bleed method is used in modern carburetor

Correct : A. to maintain air fuel ratio at all speeds

48. A carburetor which is installed above intake manifold and flow ofmixture is assited by gravity is called

Correct : B. down draught carburetor

49. Carburetor which uses horizontal draft tube is called

Correct : C. side draught carburetor

50. Actual air fuel ratio supplied by carburetor at high altitudes compared to sea level

Correct : B. rich

51. Which is not the advantage of gasoline injection as compared to carburetor

Correct : D. low volumetric efficiency

52. Which is not a method of fuel injection in SI engine

Correct : A. directly into the cylinder before the end of compression stroke

53. Continuous port fuel injection refers to injection of fuel

Correct : A. near the inlet port

54. In continuous inlet manifold injection system, the fuel is injected at a pressure of refers to injection of fuel

Correct : C. 2 bar

55. GDI refers to injection of fuel

Correct : C. directly into the cylinder

56. Which of the following is not the advantage of GDI

Correct : D. high initial cost

57. In MPFI injection system

Correct : D. all of the above

58. Which is not an advantage of MPFI system?

Correct : D. elaborate arrangement of components

59. If flame travel from point of ignition upto end of combustion chamber without change in speed, the combustion is called

Correct : B. normal

60. The combustion of mixture without a flame front is called

Correct : A. auto ignition

61. The throttle valve is placed in a draft tube

Correct : B. on engine side of the venturi

62. The choke valve is placed in a draft tube

Correct : A. on atmospheric side of the venturi

63. The venturi is the portion in a draft tube

Correct : C. minimum cross secional area

64. The main jet of the main metering system is situated

Correct : A. above the level of the petrol in float chamber

65. The nozzle lip is the level difference between

Correct : A. venturi and level of petrol in float chamber

66. The use of vent on a float chamber ensures

Correct : C. maintaining atmospheric pressure in float chamber

67. The carburetion does not perform this function

Correct : D. increasing the temperature of the mixture near to its ignition point

68. The carburetor depression is

Correct : B. the pressure drop because of which fuel is sucked

69. Operating the choke in cold starting means

Correct : A. closing the choke valve

70. In idling system, the idling port opens in a draft tube of carburetor on

Correct : B. on engine side of throttle valve

71. Stoichiometric air fuel ratio of petrol is aproximately

Correct : C. 1970-01-01 15:01:00

72. Equivalence ratio means

Correct : A. actual fuel air ratio to stoichiometric fuel air ratio

73. If air fuel ratio is greater than 16:1 then ixture is

Correct : A. lean

74. The function of the venturi in the carburetor is

Correct : D. to increase air velocity

75. To get maximum power aim is

Correct : B. to utilize all oxygen in combustion chamber

76. If the bonnet space is limited, the carburetor used is

Correct : C. horizontal draught

77. In constant choke carburetor or open choke carburetor ___________ is kept constant.

Correct : C. both air and fuel flow areas

78. A venturi of fixed dimension is used in

Correct : A. constant choke carburetor

79. In ______________ carburetor, pressure drop is kept constant.

Correct : B. constant vacuum carburetor

80. If the equivalence ratio is greater than one then, mixture is

Correct : C. rich

81. Fuel flow rate as per demand is varied by varying pressure difference in _____ carburetor.

Correct : C. solex

82. Fuel flow area is varied in ____________ carburetor.

Correct : D. su

83. In this carburetor, air lifts fuel droplets against gravity.

Correct : A. updraught

84. If inlet temperature of air increases ___________

Correct : C. both efficiency and power output decrease

85. Chemixally correct air fue ratio of octane is

Correct : B. 15.14:1

86. Which air fuel ratio gives maximum power for SI engine

Correct : D. 1970-01-01 12:01:00

87. Which air fuel ratio gives minimum BSFC

Correct : B. 1970-01-01 16:01:00

88. Rich mixture is required during

Correct : D. idling and acceleration

89. The choke is used when engine is

Correct : A. cold

90. SI engines use mixtures having AF ratio between

Correct : B. 3:1 to 17:1

91. For SI engine for maximum power, relative fuel air ratio should be

Correct : D. 1.2

92. Lean mixture is required during

Correct : C. cruising only

93. For maximum thermal efficiency aim is to

Correct : B. use all the fuel present in combustion chamber

94. The mixture requirements during staarting and idling are

Correct : A. rich and rich

95. For maximum economy mixture should be

Correct : B. lean

96. The pressure difference between float chamber and throat is

Correct : C. carburetor depression

97. When choke is closed, suction presssure is applied on

Correct : B. nozzle

98. Economiser system comes into action during

Correct : D. full throttle condition

99. During cruising, mixture provided by simple carburetor is

Correct : A. increasingly rich

100. During acceleration, mixture provided by simple carburetor is

Correct : C. lean