# Diesel power plants

## Diesel Engine Power plants Multiple Choice Questions  with Answers

1. What is the maximum temperature in the I.C. engine cylinder is of the order of(in degree Celsius)?

a) 500-1000

b) 1000-1500

c) 1500-2000

d) 2000-2500

Answer: 2000-2500

2. The thermal efficiency of diesel engines is about __________

a) 30%

b) 15%

c) 50%

d) 70%

Answer: 70%

3. The thermal efficiency of a standard Otto cycle for a compression ratio of 5.5 will be __________

a) 20%

b) 25%

c) 50%

d) 55%

Answer: 50%

4. The specific fuel consumption per B.P. hour for a petrol engine is about __________

a) 0.2 kg

b) 0.25 kg

c) 0.3 kg

d) 0.35 kg

Answer: 0.25 kg

5. Maximum temperature developed in a diesel engine is in the range of

a) 2000 - 2500 °C

b) 500 – 1000 °C

c) 1500 – 2000 °C

d) 1000 – 1500 °C

Answer: 2000 -2500 °C

6. Calculate the overall efficiency of the diesel plant if the fuel consumption is 0.24 kg per kWh and the calorific value of the fuel being 10000 kcal/kg.

a) 30.78

b) 35.83

c) 28.73

d) 36.86

Answer: 35.83

7. In petrol engines, the delay period is of the order of __________

a) 0.001 sec

b) 0.002 sec

c) 0.003 sec

d) 0.004 sec

Answer: 0.002 sec

8. The pressure at the end of compression, in petrol engines, is approximately __________

a) 10 bar

b) 20 bar

c) 25 bar

d) 35 bar

Answer: 10 bar

9. How much voltage required to produce a spark across the gap, between the sparking points?

a) 2000-4000 volts

b) 4000-6000 volts

c) 6000-10000 volts

d) 10000-12000 volts

Answer: 6000-10000 volts

10. The scavenging efficiency of a tour stroke cycle diesel engine is __________

a) between 50-85%

b) between 95-100%

c) below 50%

d) between 85-95%

Answer: between 95-100%

11. The speed of the diesel engine may vary from

a) 0 – 100 rpm.

b) 200 – 1000 rpm.

c) 500 -5000 rpm.

d) 1000 – 3000 rpm.

Answer: 1000 – 3000 rpm.

12. What is the ranging capacity of the diesel plant?

a) 50 – 750 kW

b) 100 – 1175 kW

c) 75 – 3750 kW

d) 150 – 4575 kW

Answer: 75 – 3750 kW

13. The temperature of the cooling water leaving the diesel engine should not exceed.

a) 25 °C

b) 40 °C

c) 85 °C

d) 70 °C

Answer: 40 °C

14. Heating value of diesel is around?

a) 4000 kcal/kg

b) 10000 kcal/kg

c) 15000 kcal/kg

d) 20000 kcal/kg

Answer: 10000 kcal/kg

15. The diesel plants are mainly used ________

a) As peak load plants.

b) As base load plants.

c) As standby power plants.

d) Both peak and stand by plants.

Answer: Both peak and stand by plants.

16. In a 2 stroke engine, the operation cycle are completed in how many strokes and revolution?

a) 4 strokes and 2 revolutions.

b) 2 stroke and 2 revolutions.

c) 2 strokes and 1 revolution.

d) 4 stroke and 4 revolutions.

Answer: 2 strokes and 1 revolution.

17. It is very much necessary to treat the makeup water to remove the scale forming the impurities. Which treatment is used?

a) Zeolite softener.

b) Lime or lime soda treatment

c) Both (a) and (b).

d) None of the following

Answer: Both (a) and (b).

18. Which among the following instruments are provided on the exhaust line to reduce the pressure?

a) Ductss.

b) Muffler

c) Strainers.

d) Purifiers.

Answer: Muffler

19. Which type of cylinder configuration is commonly used?

a) Vertical – in line.

b) V – type.

c) Horizontal type.

d) All of these.

Answer: Vertical – in line.

20. What is supercharging?

a) Pumping of air into the cylinder at the pressure greater than atmospheric pressure.

b) Pumping of air out of the cylinder at the pressure greater than atmospheric pressure.

c) Pumping of air into the cylinder at the pressure lower than atmospheric pressure.

d) Pumping of air out of the cylinder at the pressure lower than atmospheric pressure.

Answer: Pumping of air into the cylinder at the pressure greater than atmospheric pressure.

21. The ratio of the volume of charge admitted at N.T.P. to the swept volume of the piston is called?

a) overall efficiency

b) mechanical efficiency

c) relative efficiency

d) volumetric efficiency

Answer: volumetric efficiency

22. The lubrication cost in a diesel power plant is

a) High

b) Low

c) Moderate

d) Very low.

Answer: High

23. The identification of a two stroke engine is given by

a) Cooling system

b) Lubrication system.

c) Absence of valve.

d) All of these.

Answer: Absence of valve.

24. High output diesel engines are started by

a) Self starter.

b) Compressed air.

c) Battery.

d) Cranking.

Answer: Compressed air.

25. If the temperature of intake air in internal combustion engine increases, then its efficiency will __________

a) remain same

b) increase

c) decrease

d) none of the mentioned

Answer: decrease

26. The ignition quality of petrol is expressed by __________

a) Cetane number

b) Octane number

c) Calorific Value

d) None of the mentioned

Answer: Octane number

27. The operation of forcing additional air under pressure in the engine cylinder is known as __________

a) Supercharging

b) Scavenging

c) Turbulence

d) Pre-ignition

Answer: Supercharging

28. The mean effective pressure obtained from engine indicator indicates the __________

a) maximum pressure developed

b) minimum pressure developed

c) instantaneous pressure at any point

d) average pressure

Answer: average pressure

29. Reactors for propulsion applications are designed for__________

a) any form of uranium

b) natural uranium

c) enriched uranium

d) thorium

Answer: enriched uranium

30. What is the pour point of fuel oil?

a) Minimum temperature to which oil is heated in order to give off inflammable vapours in sufficient quantity to ignite momentarily when brought in contact with a flame

b) Temperature at which it solidifies or congeals

c) It catches fire without external aid

d) Indicated by 90% distillation temperature i.e., when 90% of sample oil has distilled off

Answer: Temperature at which it solidifies or congeals

31. In compression ignition engines, swirl denotes a __________

a) Haphazard motion of the gases in the chamber

b) Rotary motion of the gases in the chamber

c) Radial motion of the gases in the chamber

d) None of the mentioned

Answer: Rotary motion of the gases in the chamber

32. Supercharging is the process of __________

a) Supplying the intake of an engine with air at a density greater than the density of the surrounding atmosphere

b) Supplying compressed air to remove combustion products fully

c) Providing excess temperature to the sucked in gases

d) None of the mentioned

Answer: Supplying the intake of an engine with air at a density greater than the density of the surrounding atmosphere

33. The probability of knocking in diesel engines is increased by __________

a) high self-ignition temperature

b) low volatility

c) high viscosity

d) all of the mentioned

Answer: all of the mentioned

34. The object of supercharging the engine is __________

a) to increase the power output of an engine when greater power is required

b) to reduce mass of the engine per brake power

c) to reduce space occupied by the engine

d) all of the mentioned

Answer: all of the mentioned

35. The compensating jet in a carburettor supplies almost constant amount of petrol at all speeds because the __________

a) jet area is automatically varied depending on the suction

b) the flow from the main jet is diverted to the compensating jet with increase in speed

c) flow is produced due to the static head in the float chamber

d) the diameter of the jet is constant and the discharge coefficient is invariant

Answer: flow is produced due to the static head in the float chamber

36. A moderator generally used in nuclear power plants is?

a) heavy water

b) concrete

c) graphite & concrete

d) graphite

Answer: graphite & concrete

37. In a diesel engine, the duration between the time of injection and ignition is known as?

a) delay period

b) period of ignition

c) burning period

d) pre-ignition period

Answer: delay period

38. Nuclear Reactors are used __________

a) to produce heat for thermoelectric power

b) to propel ships, submarines, aircrafts

c) to produce fissionable material

d) all of the mentioned

Answer: all of the mentioned

39. Where reactor operation is designed with fast neutrons such as in reactors using highly enriched fuel, the moderator used is?

a) Carbon dioxide

b) Heavy Water

c) Graphite

d) No moderator is needed

Answer: No moderator is needed

40. The expansion of fuel in a four stroke cycle diesel engine __________

a) starts at 15° after top dead centre and ends at 30° before bottom dead centre

b) starts at top dead centre and ends at 30° after top dead centre

c) may start and end anywhere

d) starts at 15° before top dead centre and ends at 30° after top dead centre

Answer: starts at 15° after top dead centre and ends at 30° before bottom dead centre

41. A moderator, in nuclear power plants, is a medium introduced into the fuel mass in order to __________

a) slow down the speed of fast moving neutrons

b) control the reaction

c) reduce the temperature

d) extract heat from nuclear reaction

Answer: slow down the speed of fast moving neutrons

42. In a four stroke cycle petrol engine, the charge is ignited at __________

a) 30° after bottom dead centre

b) 30° before bottom dead centre

c) 30° after top dead centre

d) 30° before top dead centre

Answer: 30° before top dead centre

43. The exhaust valve in a four stroke cycle petrol engine __________

a) opens at 50° after bottom dead centre and closes at 15° before top dead centre

b) opens at 50° before bottom dead centre and closes at 15° after top dead centre

c) opens at bottom dead centre and closes at top dead centre

d) may open and close anywhere

Answer: opens at 50° before bottom dead centre and closes at 15° after top dead centre

44. The brake power of a diesel engine, keeping other parameters constant, can be increased by __________

a) increasing the pressure of intake air

b) decreasing the density of intake air

c) decreasing the pressure of intake air

d) increasing the temperature of intake air

Answer: increasing the pressure of intake air

45. In a four stroke cycle, the minimum temperature inside the engine cylinder occurs at the __________

a) end of suction stroke

b) beginning of exhaust stroke

c) beginning of suction stroke

d) end of exhaust stroke

Answer: beginning of suction stroke

46. The effective inhibitor of pre-ignition is __________

a) alcohol

b) lead

c) water

d) none of the mentioned

Answer: water

47. The reference fuels for knock rating of spark ignition engines would include __________

a) normal octane and aniline

b) iso-octane and normal hexane

c) iso-octane and alpha-methyl naphthalene

d) normal heptane and iso-octane

Answer: normal heptane and iso-octane

48. What is the purpose of testing an internal combustion engine?

a) to conform the data used in design, the validity of which may be doubtful

b) to satisfy the customer regarding the performance of the engine

c) to determine the information, which cannot be obtained by calculations

d) all of the mentioned

Answer: all of the mentioned

49. Pre-ignition is caused by the spontaneous combustion of the mixture before the end of the compression stroke, and is due to __________

a) overheated spark plug points

b) red hot carbon deposits on cylinder walls

c) cylinder walls being too hot

d) any of the mentioned

Answer: any of the mentioned

50. The fuels in order of decreasing knock tendency for spark ignition engines are __________

a) Paraffin, aromatic, napthene

b) Paraffin, napthene, aromatic

c) Napthene, aromatics, paraffin

d) Napthene, paraffin, aromatic

Answer: Paraffin, napthene, aromatic

51. In a four stroke cycle petrol engine, the pressure inside the engine cylinder during the suction stroke is __________ the atmospheric pressure.

a) equal to

b) below

c) above

d) middle

Answer: below

52. Solid fuel fabricated into various small shapes, which are assembled to form fuel elements, is in the form of __________

a) pallets

b) plates

c) pins

d) all of the mentioned

Answer: all of the mentioned

53. A diesel engine is __________ as compared to petrol engine, both running at rated load.

a) equally efficient

b) more efficient

c) less efficient

d) all of the mentioned

Answer: more efficient

54. A higher compression ratio causes __________

a) increase in detonation

b) pre-ignition

c) an acceleration in the rate of combustion

d) any one of the mentioned

Answer: any one of the mentioned

55. Which one of the following event would reduce volumetric efficiency of a vertical compression ignition engine?

a) inlet valve closing before bottom dead centre

b) inlet valve closing after bottom dead centre

c) inlet valve opening before top dead centre

d) exhaust valve closing after top dead centre

Answer: inlet valve closing before bottom dead centre

56. The control rods in the control system of nuclear reactors are used to __________

a) control fuel consumption

b) absorb excess neutrons

c) control temperature

d) all of the mentioned

Answer: absorb excess neutrons

57. Number of working strokes per min. for a two stroke cycle engine are __________ the speed of the engine in r.p.m.

a) equal to

b) one-half

c) four-times

d) twice

Answer: equal to

58. A fuel of cetane number 40 has the same ignition quality as a mixture of __________

a) 40% alpha methyl napthalene and 60% cetane

b) 40% cetane and 60% alpha methyl napthalene

c) 40% petrol and 60% diesel

d) 40% diesel and 60% petrol

Answer: 40% cetane and 60% alpha methyl napthalene

59. The two reference fuels used for cetane rating are __________

a) cetane & iso-octane

b) cetane & normal heptane

c) cetane & alpha methyl naphthalene

d) cetane & tetra ethyl lead

Answer: cetane & alpha methyl naphthalene

60. Reflector in nuclear power plants __________ neutron leakage.

a) increases

b) decreases

c) has no effect

d) all of the mentioned

Answer: decreases

61. In order to eliminate knocking in compression ignition engines, there should be __________

a) high self-ignition temperature of fuel

b) late auto-ignition

c) short delay period

d) low compression ratio

Answer: short delay period

62. Which of the following statement is correct?

a) Compression ratio for petrol engines varies from 6 to 10

b) Petrol engines work on Otto cycle

c) Higher compression ratio in diesel engines results in higher pressures

d) All of the mentioned

Answer: All of the mentioned

63. The injector nozzle of a compression ignition engine is required to inject fuel at a sufficiently high pressure in order to __________

a) inject fuel at a high velocity to facilitate atomisation

b) inject fuel in a chamber of high pressure at the end of compression stroke

c) ensure that penetration is not high

d) all of the mentioned

Answer: all of the mentioned

64. If the speed of the engine is increased, the indicated power will __________

a) increase

b) decrease

c) remain same

d) none of the mentioned

Answer: increase

65. Which material is most commonly used for shielding?

a) Carbon

b) Concrete

c) Lead

d) All of the mentioned

Answer: Lead

66. The lubrication cost in a diesel power plant is

a) High

b) Low

c) Moderate

d) Very low.

Answer: High

67. The identification of a two stroke engine is given by

a) Cooling system

b) Lubrication system.

c) Absence of valve.

d) All of these.

Answer: Absence of valve.

68. High output diesel engines are started by

a) Self starter.

b) Compressed air.

c) Battery.

d) Cranking.

Answer: Compressed air.

69. If the temperature of intake air in internal combustion engine increases, then its efficiency will __________

a) remain same

b) increase

c) decrease

d) none of the mentioned

Answer: decrease

70. The ignition quality of petrol is expressed by __________

a) Cetane number

b) Octane number

c) Calorific Value

d) None of the mentioned

Answer: Octane number