indicated mean effective pressure

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indicated mean effective pressure (IMEP)

indicated mean effective pressure (IMEP)click for a larger image
The average pressure produced in the combustion chamber during the operating cycle. It is an expression of the theoretical, frictionless power known as indicated horsepower. In addition to completely disregarding power lost to friction, indicated horsepower gives no indication as to how much actual power is delivered to the propeller shaft for doing useful work. However, it is related to actual pressures that occur in the cylinder and can be used as a measure of these pressures. IMEP is equal to brake mean effective pressure (BMEP) plus friction mean effective pressure (FMEP).
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