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Mechanical Engineering :: Internal Combustion Engines

  1. The increase in intake temperature of internal combustion engines will _________ efficiency.

  2. A.

     Have no effect on

    B.

     Increase

    C.

     Decrease

    D.

     None of these


  3. During idling, a petrol engine requires _________ mixture.

  4. A.

     Lean

    B.

     Rich

    C.

     Chemically correct

    D.

     None of these


  5. The cam shaft of a four stroke I.C. engine running at 1500 rpm will run at

  6. A.

     1500 rpm

    B.

     750 rpm

    C.

     3000 rpm

    D.

     Any value independent of engine speed


  7. Polymerization is a chemical process in which molecules of a compound become

  8. A.

     Larger

    B.

     Slowed down

    C.

     Smaller

    D.

     Liquid


  9. The theoretically correct mixture of air and petrol is

  10. A.

     10 : 1

    B.

     15 : 1

    C.

     20 : 1

    D.

     25 : 1


  11. An hmh flame speed is obtained in diesel engine when air fuel ratio is

  12. A.

     Uniform throughout the mixture

    B.

     Chemically correct mixture

    C.

     About 35% of rich mixture

    D.

     About 10% of rich mixture


  13. A stoichiometric air-fuel ratio is

  14. A.

     Chemically correct mixture

    B.

     Lean mixture

    C.

     Rich mixture for idling

    D.

     Rich mixture for over loads


  15. The temperature of interior surface of cylinder wall in normal operation is not allowed to exceed

  16. A.

     80°C

    B.

     120°C

    C.

     180°C

    D.

     240°C


  17. A two stroke cycle engine gives ________ the number of power strokes as compared to the four stroke cycle engine, at the same engine speed.

  18. A.

     Half

    B.

     Same

    C.

     Double

    D.

     Four times


  19. The fuel air ratio in a petrol engine fitted with suction carburettor, operating with dirty air filter as compared to clean filter will be

  20. A.

     Higher

    B.

     Lower

    C.

     Remain unaffected

    D.

     None of the above