Quiznetik

Applied Thermodynamics (AT) | Set 5

1. During idling, mixture provided by simple carburetor is

Correct : C. lean

2. The fuction of the choke is to provide

Correct : C. rich mixture

3. Simple carburetor provides correct quality of mixture

Correct : D. only at one throttle position

4. The correct expression for nozzle lip is

Correct : A. tip height – fuel surface height

5. The tip of the nozzle is kept

Correct : B. at level above the fuel level in float chamber

6. The drawbacks of carburetor includes

Correct : D. all of the above

7. MPFI means

Correct : B. multi point fuel injection

8. In port injection system, location of injector is

Correct : C. inside intake manifold near intake port

9. In carburetor, choke is located on which side of the venturi?

Correct : B. air filter side

10. In carburetor, throttle valve is located on which side of the venturi?

Correct : A. engine side

11. In complete caruretor, idling passage opens in a draft tube at which position?

Correct : A. engine side of throttle valve

12. The cold start injector provides

Correct : B. rich mixture

13. Ignition lag, spreading of flame and after burning are the stages observed during combustion in

Correct : A. petrol engines

14. The combustion will not start immediately after spark because of

Correct : C. ignition lag

15. The time interval between formation of spark and appreciable pressure rise is

Correct : B. ignition lag

16. A motoring curve is plotted when

Correct : D. the cycle is not fired

17. Which of the following is not necessary condition for starting of combustion process in SI engines?

Correct : A. compression of charge

18. Effect of spark in SI engines is____

Correct : D. rise in temperature

19. In SI enginesmaximum amount of fuel is burnt during the stage____

Correct : C. flame propagation

20. In SI engines the flame travels in____

Correct : A. spherical shape

21. In D-MPFI system the quantity sensed is ____

Correct : A. pressure

22. The D-MPFI system responds to vacuum sensed in____

Correct : B. intake manifold

23. L-MPFI ststem responds to____

Correct : D. flow rate

24. Arrange the phases of combustion in ascending order according to amount heat evolved in each phase

Correct : A. ignition lag, after burning, flame propagation

25. In SI engines flame speed decreases with increase in

Correct : D. residual gases

26. In SI engines, Maximum flame speed is obtained when equivalance ratio is___

Correct : C. between 1.1 to 1.2

27. With increase in compression ratio, flame travels

Correct : A. faster

28. In SI engines flame speed always increases with____

Correct : D. compression ratio

29. With increase in speed, the crank angle required for flame propagation___

Correct : C. remains same

30. If cooling water temperature is decreased flame speed___

Correct : B. decreases

31. Increasing cooling water temperature in SI engines, kncocking tendency_____

Correct : A. increases

32. To reduce knocking, the fuel in SI engine should have ____ self ignition temperature

Correct : A. low

33. Detonation in SI engine means

Correct : D. auto-ignition of charge after the delay period is over

34. Knocking in SI engine occurs when___

Correct : B. flame reaches after the delay period is over

35. Pre-ignition takes place when____

Correct : C. ignition starts before spark

36. Larger combustion chambers

Correct : A. increase detonation

37. To prevent knocking flame propagation should be

Correct : A. retareded

38. To reduce knocking in SI engines, self ignition temperature of fuel should be ____

Correct : A. high

39. Which of the following is not an effect of increased intake temperature?

Correct : D. does not affect anything

40. As load increases, the knocking tendency of SI engines____

Correct : A. increases

41. As the speed of flame travel increases, detonation___

Correct : B. decreases

42. AS distance of flame travel increases, detonation

Correct : A. increases

43. Detonation tendency is maximum for air:fuel ratio___

Correct : C. 12:1 to 14;1

44. To reduce detonation, the spark plugh should be located

Correct : C. centrally

45. Which is not a probable location of preignition?

Correct : D. intake valve

46. Knocking in SI engines will be less if

Correct : C. delay period is high and flame speed is high

47. In SI engines, to aviod knock, combustion chamber should have___

Correct : A. small bore

48. Octane rating is___

Correct : D. measure of fuel resistance to knock in si engines

49. For octane rating a standard reference fuel consists of

Correct : C. combination of 2,2,4 trimethyl pentane and n-heptane

50. 2,2,4 trimethyl pentane has octane number equal to

Correct : C. 100

51. n-heptane has octane number equal to

Correct : A. 0

52. Octane number 60 means, the fuel has antiknock proper equal to fuel from by

Correct : B. 60% of iso octane and 40% n-heptane

53. Dopes are___

Correct : B. chemical which will decrease knocking tendency of fuel

54. RON means ____

Correct : D. research octane number

55. MON means ___

Correct : D. motor octane number

56. RON is calculated at___

Correct : A. low speed and low temperature

57. Which is correct expression?

Correct : C. sensitivity=ron-mon

58. Sensitivity shows

Correct : A. change in eprformance of fuel under test condition and practical condition

59. Higher sensitivity of fuel shows___

Correct : B. poor oerformance under serve conditions

60. A 4-cylinder, 4-stroke petrol engine has,swept volume=0.001cubic meter and N=4200rpm. The power developed within the enigne cylinder is

Correct : B. 140kw

61. B.P of a four cylinde, four stroke engine is measured by brake dynamometer which develops a torque of 1000N-M at 4200rpm. The B.P is about

Correct : A. 440kw

62. In an eight cylinder engine the fuel suplied was 4000kg in 2 hours and the out put is 8000KW. Its bsfc is about

Correct : C. 0.25kg/kwh

63. brake thermal efficiency of ci engine is about

Correct : B. 30-40%

64. four cylinder engine , the indicated power is 100KW and brake power is 20KW/cylinder . Its mechanical efficiency is about

Correct : C. 0.8

65. brke mean effective pressure and indicated mean effective pressure of an ic engine are 8br and 10 bar resp. the mechanical efficiency of an engine when runnign at 4000 rpm is

Correct : A. 0.8

66. an engine develops 12KW and frictional power is 4KW . The mechanical efficiency is about

Correct : C. 0.75

67. an engine develops 100 Kw wihing the cylinder using fuel having calrofic value of 40000kj/kg with brake thermal efficiency 0.24 and mechanical efficiency 0.8. the fuel consumprion in kg/s…………….?

Correct : A. 30

68. A four cylinde si engine develops 100 kw running at a constant speed . When eginition of each cylinder is cut-off successively at the same speed , the BP is 71, 70, 71, 72 KW. The FP of engine and mechanical efficiency are

Correct : B. 16kw, 86.2%

69. a vertical single cylinder four stroke diesel engine has a bore of 80mm and stroke of 100mm resp. it is water cooled and develops a torque of 305 N-m . What is the mean effective pressure …………?

Correct : B. 5.875 bar

70. a diesel engine consumes 5 grams fuel per second and develops a brake power 75KW. It has a mechanical efficiency of 85%. What would be the bsfc………?

Correct : C. 0.066 g/kw s

71. a diesel engine consumes 5 grams fuel per second and develops a brake power 75KW. It has a mechanical efficiency of 85%, bsfc is 0.066 g/KW s . What would be the isfc….?

Correct : B. 0.204 kg/kwh

72. a four stroke gas engine has a bor of 20cm and stroke of 35 cm . What would be the swept volume of the engine

Correct : D. 7853.93 cc

73. a diesel engine consumes at the rate of 5.5gm/ses and develops a power of 75KW . If the mechanical efficiency is 85% and calorific value is 44 MJ/kg. what would be the bsfc

Correct : A. 0.074 g/kws

74. a six cylinder gasoline engine operates on four stroke cycle. It runs at the speed of 4100rpm and develops a torque of 160N-m. what would be the brake power of the engine ……..?

Correct : B. 68.66 kw

75. a sic cylinder gasoline engine operates on a four stroke cycle. The bore of each cylinder is 80mm and the stroke is 100 mm. it runs at a speed of 4100 rpm and develops a brake power of 68.66Kw………what would be the brake mean effective pressure…………….?

Correct : C. 6.66bar

76. a six cylinder gasoline engine operates on the four stroke cycle . The bore of each cylinder is 80 mm and stroke is 100mm. What would be the compression ratio of the engine if clearnce volume per cylinder is 70cc

Correct : B. 8.18

77. if the compression ratio of otto cycle is 8.18, what would be the air standard efficiency

Correct : C. 0.428

78. if the compression ration of otto cycle is 8.18 and brake thermal efficiency of actual cyle is 29.03%........what would be the relative efficienct

Correct : A. 0.51109

79. a six cylinder four stroke petron engine having a bore of 90 mm and stroke of 100mm and runs at a speed of 2500 rpm. What would be the indicated power

Correct : C. 67.593kw

80. a six cylinder four stroke petrol engine develops a indicated power of 67.593 KW with indicated mean specific fuel consumption os 0.3kg/Kwh. What would be the mas flow rate of the fuel in kg/hr

Correct : C. 20.278

81. the air standard efficiecny of engine is 0.42647 and corsponding relative efficiecny is 0.55. what would be the corsponding indicated thermal efficiency

Correct : A. 0.2346

82. what would be the brake power of the engine, if the net brake load on the engine is 1470 N, effective brake corcumeference is of 4m and engine runs at the speed of 233.33rpm

Correct : C. 26.589kw

83. if the brake power and indicated power of an engine are 22.286 KW and 56.589KW, what would be mecanicale efficiency of an engine ………..?

Correct : D. 0.86

84. what would be the number of powe strokes per min ……..? If a six cylinder four stroke engine runs at 233.33 rpm and the number of missed powe stroke is 8.33 per min

Correct : C. 108.66

85. actual number of stroke per min will be equll to

Correct : C. theroricl stroke per min - missed stroke per min

86. a four cylinder petrol engine with 70mm bore and 100 mm stroke length working on four stroke pricniple develops a torque 140 N-m at 4000 rpm……what would be the brake power of the engine ……?

Correct : A. 58.65kw

87. what would be the brake thermal efficiency of the engine, if the brake power of the engine is of 58.65KW, fuel consumption is 14kg/hr and the calrofic value of the fuel is 42500kj/kg

Correct : A. 0.3548

88. what would be the compression ratio of the engine if the clearnce volume is 0.065lit and the engine bore is of 70mm and the stroke is of 100mm

Correct : C. 6.923

89. what would be the mean effective pressure of the engine if the area of the indicator diagram is 13 cm2 , length of the indicator diagram is of 6cm and spring constant 2.9 bar/cm

Correct : B. 5.8bar

90. what would be the mass flow rate of gasoline in kg/s, if the engine consumes 8lit/hr, taking the specific gravity of the gasoline is 0.8

Correct : A. 0.00178

91. what would be the mass flow rate of the gasoline in kg/s, the engine sonsumes 8lit/hr of gasoline, taking density of gasoline is 800 kg/cubic meter

Correct : B. 0.00178

92. a single cylinder engine operating at 2000 rpm develops a torqu of 8 N-m and the indicated power of the engine is 2.0KW. What would be the frictional power

Correct : C. 0.3253kw

93. for four cylinder four stroke petrol engien the bore is 11cm and stroke is 13cm, running at speed of 2250 rpm. What is the swept volume of the engine

Correct : C. 0.37 cubic meter per second

94. a single cylinder four stroke engine having bore 18 cm and stroke 36cm, revolving at 285 rpm and having mean effective pressure 7.2 bar. The indicated power is

Correct : A. 7.85kw

95. what would be the mean effective pressure of the engine if the area of the positive loop of the indicator diagram is of 5.75 squr cm, area of negative loop of the indicator diagram 0.25 squre cm and the length of the indicator diagrma is of 5.5cm

Correct : A. 4bar

96. what would be the heat supplied to the engine in KJ/s, if the engine consumes 8 lit of gasoline per second. Take caloric value and specific gravity of fuel is 44000 kj/kg and 0.8 resp.

Correct : A. 9.78

97. what would be the heat supplied to the engine in KJ/s, if the engine consumes 8 lit of gasoline per second. Take caloric value and density of fuel is 44000 kj/kg and 800 kg per cubic meter resp.

Correct : B. 9.78

98. if the brake thermal efficiecny and indicated thermal efficiecny of the engine is 28% and 35%. What would be the mechanical efficiency of the engien

Correct : B. 0.8

99. what is the density of the fuel whose specific gravity is 0.8

Correct : A. 800 kg/ cubic meter

100. what would be the air fuel ratio ot the engine if the air consumtion time for 0.1 cubic meter as 16.3 sec and whose density is 1.175kg per cubic meter and fuel consumtion time for 10 cc as 20.sec whos specific gravity is 0.7…….

Correct : D. 20.6