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Mechanical Engineering :: Internal Combustion Engines

  1. The brake power of a diesel engine, keeping other parameters constant, can be increased by

  2. A.

     Decreasing the density of intake air

    B.

     Increasing the temperature of intake air

    C.

     Increasing the pressure of intake air

    D.

     Decreasing the pressure of intake air


  3. A supercharged engine as compared to an ordinary engine

  4. A.

     Requires smaller foundation

    B.

     Is lighter

    C.

     Consumes less lubricating oil

    D.

     All of these


  5. In a petrol engine, if diesel is used, then the engine will

  6. A.

     Not run

    B.

     Run more efficiently

    C.

     Run at high speed

    D.

     Explode


  7. A diesel engine as compared to petrol engine (both running and rated load) is

  8. A.

     More efficient

    B.

     Less efficient

    C.

     Equally efficient

    D.

     Other factors will decide it


  9. Supercharging is the process of supplying the intake air to the engine cylinder at a density _________ the density of the surrounding atmosphere.

  10. A.

     Equal to

    B.

     Less than

    C.

     Greater than

    D.

     None of these


  11. Air fuel ratio at which a petrol engine cannot work is

  12. A.

     8 : 1

    B.

     10 : 1

    C.

     15 : 1

    D.

     20 : 1 and less


  13. In a four stroke cycle petrol engine, the expansion

  14. A.

     Starts at top dead center and ends at bottom dead center

    B.

     Starts at 30° before top dead center and ends at 50° before bottom dead center

    C.

     Starts at 30° after top dead center and ends at 50° after bottom dead center

    D.

     May start and end anywhere


  15. The volumetric efficiency of a well designed engine may be

  16. A.

     30 to 40%

    B.

     40 to 60%

    C.

     60 to 70%

    D.

     75 to 90%


  17. Compression loss in I.C engines occurs due to

  18. A.

     Leaking piston rings

    B.

     Use of thick head gasket

    C.

     Clogged air inlet slots

    D.

     All of the above


  19. The reference fuels for knock rating of spark ignition engines would include

  20. A.

     Iso-octane and alpha-methyl naphthalene

    B.

     Normal octane and aniline

    C.

     Iso-octane and normal hexane

    D.

     Normal heptane and iso-octane