What is the difference between Mean Effective Pressure (MEP) and Mean Indicated Pressure (MIP)?

Mean Effective Pressure

It is the theoretical constant pressure which may be assumed acting on the piston during power stroke.

Indicated Mean Effective Pressure or Mean Indicated Pressure (MIP)

It is a pressure which on acting upon the piston, performs the same works as the actual pressure on the operating cycle. It is the ratio of the work done during the working stroke to the swept volume. It is determined graphically from a diagram or calculated from engine parameters.


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Anand Gautam

Anand Gautam is a marine engineer, Graduated from M.E.R.I. Mumbai. He likes to sail onboard ship and is one who is passionate about his job. He loves to share his knowledge, information, and ideas to everyone in a simplified way just for his satisfaction.


  • Mean effective pressure is a term used for calculation of mechanical efficiency while using a brake/dynamometer.
    Mean indicated pressure is used on ships while checking performance. And is calculated by using indicator diagrams.

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