Automobile Engineering Interview Question and Answers Part 2

Automobile Engineering Basic Interview Question , quiz ,viva , oral Examination

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39. What is Gasoline Direct Injection?

The gasoline (petrol) is directly into the cylinder at the end of compression stroke as such in diesel engines. This is called Gasoline Direct Injection (GDI)

40. What is conventional ignition system?

The conventional ignition system gets its electrical voltage either from battery or dynamo, which will be boosted to a very high voltage due to which spark is produced in the cylinder to combust the mixture.

41. Define common rail injection system.

A common rail which is maintaining high fuel pressure is connected to individual fuel injectors of a multi cylinder engine.

42. What is unit injection system?

It is an integrated direct fuel injection system for diesel engines, combining the injector nozzle and the injection pump in a single component

43. What is a rotary distributor?

The rotary distributor has a rotating element, which releases a high intensity spark to the individual spark plugs according to the engine firing order.

44. What is the function of a spark plug?

The spark plug is a device to produce electric spark to ignite the compressed air-fuel mixture inside the cylinder.

45. What is an Electronic ignition system?

The ignition system, in which the mechanical contact points are replaced by electronic triggering and switching devices, is known as electronic ignition system.

46. What are the functions of Turbo chargers?

• To produce more power from the same size engine
• To provide the altitude compensation
• To improve more complete combustion & hence less emissions

47. Why the engine emissions to be controlled?

Some of the engine emissions are carcinogenic. Moreover, the engine emissions led to green house effect. For these reasons, the engine emissions need to be controlled.

48. What are the advantages of petrol injection?

• High power can be developed
• It has quick starting characteristics
• It has lowest specific fuel consumption
• Less engine emissions than carbureted engines

49. What is super charging?

The process of increasing the density of inducted charge/ air is known as supercharging. It is performed for the following reasons.
• To produce more power from the same size engine
• To provide the altitude compensation
• To improve more complete combustion & hence less emissions

50. What is meant by carburetion in I.C engine?

The method of preparing the air-fuel mixture in an IC engine is known as carburetion. The device used for this purpose is known as carburetor

51. What are the advantages of electronic fuel injection system over conventional injection?

• Cold starting is easier
• High fuel economy
• Less engine emissions
• Quick response to varying engine operating conditions

52. What are the functions of generator and starting motor?

The function of the generator is to produce electricity to charge the battery. The starting motor is used to crank the engine during the starting condition.

53. What is the function of an ignition system in I.C engine?

The function of an ignition system is to ignite the air-fuel mixture at the end of the compression stroke.

54. State the requirements of ignition system? And state its types

• It should consume minimum of power and produce high intensity spark across spark plug electrodes
• It should have a sufficient spark duration which is sufficient to establish burning of air-fuel mixture under all operating conditions
• It should provide sufficient ignition energy over the entire speed range of the engine
• Good performance at high speed
• Longer life of contact breaker points and spark plug
• Adjustment of spark advance with speed and load

Types:

Battery ignition
Magneto ignition
Electronic ignition

55. What is the ignition advance?

When the speed of the engine increases, the ignition timing also needs to be advanced for proper combustion. This process is known as ignition advance.

56. What are the difference between battery coil ignition and magneto ignition system?

battery coil ignition vs magneto ignition system

57. What is the sealed head lamp system?

A sealed headlamp system is a type of unitized lamp with a parabolic reflector, one or more filaments and a glass or polycarbonate lens all permanently attached together and sealed.

58. What is the function of carburetor?

The function of a carburetor is to prepare the air-fuel mixture according to the engine operating conditions.

60. List the different methods of battery charging.

• Constant current charging
• Constant voltage charging
• High rate charging
• Slow rate charging

61. State the principle of working of an A.C.Generator.

The basic principle of ac generator is electromagnetic induction when a coil of a conductor moves in a magnetic field the electrons in it starts moving because of attraction and repulsion of magnetic field. Thus, an emf is induced in it.

62. In what respect does a Dynamo differ from an Alternator?

i). Dynamo produces Direct Current (DC), while Alternator produced Alternating Current (AC) which can be converted to DC using rectifiers
ii). Alternator is lighter in construction than dynamo for the same output

63. What is the purpose of Stator in the Torque Converter?

The stator resides in the center of the torque converter. Its job is to redirect the fluid returning from the turbine before it hits the pump again. This dramatically increases the efficiency of the torque converter.

64. What are the components of lead acid battery?

• Lead terminals
• Electrolyte
• Internal plates (positive and negative plates)
• Resilient Plastic container

65. What are the different types of starter motor drives?

• Bendix drive
• Overrunning drive
• Outboard drive

66. What are the chemicals used in battery?

PbO2 – Positive plate
Pb – Negative plate
Electrolyte – Diluted Sulphuric acid

67. What is a dry charged battery?

The battery is built, charged, washed and dried, sealed, and shipped without electrolyte. It can be stored for up to 18 months. When put into use, electrolyte and charging are required

68. What is the purpose of the grid?

The more “plates” in the grid, the more surface area exposed to the electrolyte, hence the more power produced.

69. How will you distinguish a positive plate from a negative plate in a lead acid battery?

The positive plates are coated with PbO2 and chocolate brown in color
The negative plates are coated with spongy lead and grey in color.

70. What is the function a cut out in a charging system?

The cut out permits the current flow from dynamo/alternator to battery for charging while it does not permit the reverse flow of current.

71. What is the function of regulators in a charging system?

Current regulator – regulates the alternator/dynamo current for charging the battery (constant current charging mode)
Voltage regulator – regulates the alternator/dynamo voltage for charging the battery (constant voltage charging mode)