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Homework Help: Diesel Engines - Power question

  1. Jan 17, 2008 #1
    1. The problem statement, all variables and given/known data
    Please can someone help me with this....
    I have a question on a four stroke diesel engine. I have been given the stroke length of 500mm and the bore size of 300mm. The compression ratio as 18/1 and the speed of revolution of 600rpm. Also the ambient air conditions are assumed to be 20C at 1 bar. Max cylinder pressure = 100 bar and exhaust gas temperature = 480C

    It asks to calculate the power developed per cylinder using the air conditions at the start of the cycle?

    2. Relevant equations

    3. The attempt at a solution

    Now i have answerd the previous question which was to calculate the thermal efficiency of the cylce. So as this is a Dual Cycle i have drawn it and calculated all the temperature points and worked out the efficiency which was 67%. Correct

    It says calculate the power from the initial air conditions but i have tried to do this by using Power = Work done x cycles per second

    I have worked out the Work done as Qin - Qout and multiplied this by 5 cycles per second (as 600 rpm is 10 rps and there are 2 revolutions in one cycle as it is 4 stroke).

    i am not getting the correct answer which is supposed to be 153KW.


    Last edited: Jan 18, 2008
  2. jcsd
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