Quiznetik

Internal Combustion Engines (I.C. Engines) | Set 3

1. The knock in diesel engine occurs due to

Correct : A. instantaneous and rapid burning of the first part of the charge

2. A stoichiometric air-fuel ratio is

Correct : A. chemically correct mixture

3. Mechanical efficiency is the ratio of

Correct : C. brake power to indicated power

4. Most commonly used lubrication system in automobiles is the

Correct : B. pressure system

5. Friction that occurs between the layers of oil film is called

Correct : A. viscous friction

6. Crankcase ventilation, is provided

Correct : D. to remove blow by

7. the most important property of the lubricant is

Correct : B. viscosity

8. The maximum pressure in the lubrication system is controlled by

Correct : C. valve relief

9. The lubricants commonly used in the automobiles are

Correct : B. vegetable oils

10. Detergents are oil additives used to

Correct : C. prevent sludge formation

11. Oil pressure in the dry sump lubrication system is around

Correct : C. 3 bar - 8 bar

12. For mep decreases when using

Correct : C. larger number of smaller cylinders

13. With increase in compression ratio, mechanical efficiency

Correct : A. increases

14. Blow by losses are

Correct : C. proportional to the square root of inlet pressure

15. Mist lubrication system is mainly used in

Correct : C. two-stroke petrol engine

16. Additives are added in lubricant to have

Correct : D. all of the above

17. The principal surfaces requiring lubrication in an IC engine are

Correct : D. none of the above

18. The heat given to cooling medium in IC engines is about

Correct : B. 30-40%

19. Radiator is provided to

Correct : A. cool the jacket water

20. Thermostat is used in radiators to

Correct : C. control the water temperature

21. As the compression ratio increases, there is a

Correct : D. marginal reduction in heat rejection

22. Spark timing other than minimum spark advance for best torque (MBT) results in

Correct : B. more beat rejection

23. Direct system of cooling air is one which

Correct : C. hot water is simply discharged

24. In evaporate cooling systems, heat absorbed per kg of coolant air is equal to

Correct : C. latent heat of the coolant

25. Pump used in the forced cooling system is normally

Correct : D. centrifugal pump

26. Limitations of air cooling systems are

Correct : C. higher working temperature compared to water cooling

27. Which is more viscous lib oil

Correct : D. SAE 80.

28. In a naturally aspirated diesel engine, the air is supplied by

Correct : C. a vacuum chamber

29. The measurement of frictional power by Willans line is applicable only to

Correct : B. CI engines at a particular speed

30. Morse test is applicable only to

Correct : C. multicylinder CI engines

31. The most accurate method of determining fp is by

Correct : C. measurement of brake and indicated power

32. In the air box method of measuring air flow, the air box is provided to

Correct : C. damp out the pulsations

33. The air box/swept volume ratio should be in the range for single-cylinder engines

Correct : C. 500 600%

34. The best method of measuring speed is by

Correct : C. magnetic pickup

35. Flame ionization detector is used for measuring

Correct : B. HC

36. Chemilumine scence analyzer is used for measuring

Correct : A. NOx

37. Non-dispersive infra-red analyzer is widely accepted instrument for measuring

Correct : C. CO

38. Thermal efficiency varies

Correct : A. inversely as sfc

39. Mechanical efficiency is ratio of

Correct : C. bp to ip

40. For N is the rpm, number of power strokes per minute in a four-stroke engine is

Correct : B. N/2

41. If N is the rpm, number of power strokes per minute in a two-stroke engine is

Correct : A. N

42. The spark timing and combustion rate should be such that

Correct : B. one half of the total pressure occurs at TDC

43. Volumetric efficiency is a measure of

Correct : C. breathing capacity of the engine

44. Indicated power is directly proportional to

Correct : B. air consumption

45. Turbocharger engines are those in which charge density is increased by

Correct : B. compressors driven by exhaust gas turbine

46. Brake thermal efficiency of SI engine is in the range

Correct : B. 25% to 35%

47. The volumetric efficiency of a well-designed engine is in the range

Correct : D. 75 to 90%

48. The major contributor of Carbon monoxide is

Correct : A. Motor vehicle

49. Apart from hydrocarbons, the main pollutants in the engine exhaust are

Correct : C. CO and NOx

50. Maximum allowable hydrocarbon in the car emission are approximately

Correct : B. 100 ppm

51. CO in the exhaust of a car engine should not be more than:

Correct : A. 0.5%

52. The PCV (Positive Crankcase Ventilation) valve is located between the

Correct : D. Intake manifold and crankcase

53. In case of engines backfiring, the PCV valve:

Correct : B. Closes

54. The position of the PCV valve plunger at idle speed is

Correct : A. Towards the valve outlet side

55. The function of charcoal granules is to absorb:

Correct : C. Petrol Vapour

56. The liquid – vapour separator is located near the

Correct : A. Fuel tank

57. EGR (Exhaust Gas Recirculation) system is employed for controlling emissions of:

Correct : C. NOx

58. The main purpose of the diverter valve in the air injection system is to

Correct : B. Prevent back fire in the exhaust system

59. The catalyst used in the reduction converter is

Correct : C. Rodium

60. The catalyst used in the converter for oxidizing HC and CO is

Correct : D. Platinum

61. In a three-way converter, the first converter controls

Correct : C. NOx

62. The air fuel ratio required for the efficient operation of a three approximately

Correct : C. 15:1

63. Which stage of vehicle emission norms presently applicable in India in Internal Combustion Engine?

Correct : B. Bharat Stage IV

64. Which of the following is one of the major exhaust emissions from CI engines compared to SI engines?

Correct : B. Particulates

65. Which of the following causes the photochemical smog?

Correct : D. NOx and HC

66. What does the blue smoke in diesel engine indicate?

Correct : A. Unburnt oil

67. During which condition of the vehicle does NOx emission in SI engine will be lowest?

Correct : B. Idling

68. For what purpose is the Rhodium used?

Correct : B. To reduce NOx

69. Why are lead compounds added in petrol?

Correct : B. Reduce HC emission