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Mechanical Engineering :: Internal Combustion Engines

  1. In a coil ignition system of petrol engines, a condenser is connected across the contact breaker in order to

  2. A.

     Prevent sparking across the gap between the points

    B.

     Cause more rapid break of the primary current, giving a higher voltage in the secondary circuit

    C.

     Both (A) and (B)

    D.

     None of the above


  3. The fuel in diesel engine is normally injected at pressure of

  4. A.

     5-10 kg/cm²

    B.

     20-25 kg/cm²

    C.

     60-80 kg/cm²

    D.

     90-130 kg/cm²


  5. The self ignition temperature of petrol is _________ as compared to diesel oil.

  6. A.

     Same

    B.

     Lower

    C.

     Higher

    D.

     None of these


  7. Which of the following statement is correct?

  8. A.

     Compression ratio for petrol engines varies from 6 to 10

    B.

     Higher compression ratio in diesel engines results in higher pressures

    C.

     Petrol engines work on Otto cycle

    D.

     All of the above


  9. The air standard efficiency of an I.C. engine depends on

  10. A.

     Fuel used

    B.

     Speed of engine

    C.

     Compression ratio

    D.

     None of these


  11. Scavenging air in diesel engine means

  12. A.

     Air used for combustion sent under pressure

    B.

     Forced air for cooling cylinder

    C.

     Burnt air containing products of combustion

    D.

     Air used for forcing burnt gases out of engine's cylinder during the exhaust period


  13. If petrol is used in a diesel engine, then

  14. A.

     Low power will be produced

    B.

     Efficiency will be low

    C.

     Higher knocking will occur

    D.

     Black smoke will be produced


  15. The calorific value of gaseous fuels is expressed in terms of

  16. A.

     kcal

    B.

     kcal/kg

    C.

     kcal/m²

    D.

     kcal/m3


  17. A diesel engine has compression ratio from

  18. A.

     6 to 10

    B.

     10 to 15

    C.

     15 to 25

    D.

     25 to 40


  19. A petrol engine has compression ratio from

  20. A.

     6 to 10

    B.

     10 to 15

    C.

     15 to 25

    D.

     25 to 40