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Mechanical Engineering :: Internal Combustion Engines

  1. If the compression ratio of an engine working on Otto cycle is increased from 5 to 7, the percentage increase in efficiency will be

  2. A.

     2%

    B.

     4%

    C.

     8%

    D.

     14%


  3. Supercharging is essential in

  4. A.

     Diesel engines

    B.

     Gas turbines

    C.

     Petrol engines

    D.

     Aircraft engines


  5. Which of the following statement is correct regarding petrol engines?

  6. A.

     A fine fuel spray mixed with air is ignited by the heat of compression which is at a high pressure

    B.

     The fuel supplied to the engine cylinder is mixed with necessary amount of air and the mixture in ignited with the help of a spark plug

    C.

     The fuel is first evaporated after passing through a carburettor and is mixed with air before ignition

    D.

     All of the above


  7. The firing order in an I.C. engine depends upon

  8. A.

     Arrangement of the cylinders

    B.

     Design of crankshaft

    C.

     Number of cylinders

    D.

     All of these


  9. The colour of exhaust from diesel engine is generally

  10. A.

     White

    B.

     Bluish

    C.

     Black

    D.

     Violet


  11. A heat engine utilizes the

  12. A.

     Calorific value of oil

    B.

     Low heat value of

    C.

     High heat value of oil

    D.

     Mean heat value of oil


  13. In the opposed piston diesel engine, the combustion chamber is located

  14. A.

     Above the piston

    B.

     Below the piston

    C.

     Between the pistons

    D.

     There is no such criterion


  15. A mixture containing 65% of iso-octane and 35% of normal heptane will have

  16. A.

     Cetane number 65

    B.

     Octane number 65

    C.

     Cetane number 35

    D.

     Octane number 35


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

  18. A.

     Increase

    B.

     Decrease

    C.

     Remain same

    D.

     None of these


  19. The ratio of indicated thermal efficiency to the corresponding air standard cycle efficiency is called

  20. A.

     Net efficiency

    B.

     Efficiency ratio

    C.

     Relative efficiency

    D.

     Overall efficiency