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Mechanical Engineering :: Internal Combustion Engines

  1. The specific fuel consumption per B.P. hour for a diesel engine is about

  2. A.

     0.2 kg

    B.

     0.25 kg

    C.

     0.3 kg

    D.

     0.35 kg


  3. The ignition quality of petrol is expressed by

  4. A.

     Cetane number

    B.

     Octane number

    C.

     Calorific value

    D.

     All of these


  5. The ignition quality of diesel oil is expressed by

  6. A.

     Cetane number

    B.

     Octane number

    C.

     Calorific value

    D.

     None of these


  7. A 5 BHP engine running at full load would consume diesel of the order of

  8. A.

     0.3 kg/hr

    B.

     1 kg/hr

    C.

     3 kg/hr

    D.

     5 kg/hr


  9. In a cycle, the spark lasts roughly for

  10. A.

     1 sec

    B.

     0.1 sec

    C.

     0.01 sec

    D.

     0.001 sec


  11. In a typical medium speed 4-stroke cycle diesel engines

  12. A.

     Exhaust valve opens at 35° before bottom dead center and closes at 20° after top dead center

    B.

     Exhaust valve opens at bottom dead center and closes at top dead center

    C.

     Exhaust valve opens just after bottom dead center and closes just before top dead center

    D.

     May open and close anywhere


  13. The octane number of petrol, generally available, is

  14. A.

     20 to 40

    B.

     40 to 60

    C.

     60 to 80

    D.

     80 to 100


  15. The cetane number of diesel oil, generally available, is

  16. A.

     20 to 25

    B.

     25 to 30

    C.

     30 to 40

    D.

     40 to 55


  17. The ratio of the work obtained at the crankshaft in a given time to the energy supplied during the same time is called

  18. A.

     Mechanical efficiency

    B.

     Overall efficiency

    C.

     Indicated thermal efficiency

    D.

     Volumetric efficiency


  19. Which of the following statements is correct?

  20. A.

     All the irreversible engines have same efficiency

    B.

     All the reversible engines have same efficiency

    C.

     Both Rankine and Carnot cycles have same efficiency between same temperature limits

    D.

     All reversible engines working between same temperature limits have same efficiency