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Please tell me if this figure seems right

  1. Mar 21, 2014 #1
    I am using a software called GT Power for a project and it is giving an heat transfer rate value of the gases to cylinder wall of about 54kW. Does this seem about right for an engine to produce? I have been told to use the initial model in the software for a KTM 450 EXC bike engine. The engine itself outputs about 50kW I think, the heat transfer rate of 54kW does not seem right to me. Statistically how much heat is transferred to a cylinder wall during combustion in an engine?

    Thank you.
  2. jcsd
  3. Mar 21, 2014 #2


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    Science Advisor
    Homework Helper

    All the heat from burning the fuel has to go somewhere, and the three main places it can go are
    (1) Mechanical work done by the engine
    (2) Through the cylinder walls into the cooling system
    (3) Out of the cylinder and into the tailpipe as hot exhaust gas.

    If the efficiency of the engine is less than 50%, then (2) + (3) is greater than (1), so your numbers COULD be right. Whether they ARE right is a different question (and I don't know the answer to that).
  4. Mar 21, 2014 #3


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    Staff: Mentor

    And 67hp sounds a bit high for a 450. Is that really its stock horsepower? My 2003 CRF450 puts out about 50hp. :biggrin:
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