mean effective pressure


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mean effective pressure

[′mēn i¦fek·tiv ′presh·ər]
(mechanical engineering)
A term commonly used in the evaluation for positive displacement machinery performance which expresses the average net pressure difference in pounds per square inch on the two sides of the piston in engines, pumps, and compressors. Abbreviated mep; mp. Also known as mean pressure.

Mean effective pressure

A term commonly used in the evaluation for positive displacement machinery performance which expresses the average net pressure difference in pounds per square inch (psi) on the two sides of the piston in engines, pumps, and compressors. It is also known as mean pressure and is abbreviated as mep or mp.

In an engine (prime mover) it is the average pressure which urges the piston forward on its stroke. In a pump or compressor it is the average pressure which must be overcome, through the driver, to move the piston against the fluid resistance.

The criterion of mep is a vitally convenient device for the evaluation of a reciprocating engine, pump, or compressor design as judged by initial cost, space occupied, and deadweight. See Compressor, Thermodynamic cycle, Vapor cycle

References in periodicals archive ?
The variation of CO emission on volumetric basis with respect to brake mean effective pressure for the various fuel blends and neat diesel are shown in Fig.
6 shows the variation of hydrocarbon emission with brake mean effective pressure under various compression ratios.
The NO emissions of the engine using different fuel blends and neat diesel with respect to brake mean effective pressure for the compression ratios 15, 17 and 19 are shown in Fig.
The black smoke emission resulting from combustion of diesel-ethanol-biodiesel blends and neat diesel are plotted against the brake mean effective pressure in the Fig.
98kJ/kW-hr for E25 blend at the compression ratio of 19 under the economic loading condition at the brake mean effective pressure of 0.
In addition, indicated horse power, break mean effective pressure and specific fuel consumption calculated from the experiments.
The results from the first experiment shown that, the best engine performance for indicated pressure (IP), indicated horse power (IHP), shaft horse power (SHP), break horse power (BHP) and break mean effective pressure (BMEP) were obtained at 220 bar and the best engine SFC is obtained at 200 bar or current fuel injection pressure.
The results from the second experiment on fixed engine speed and variation engine loads shown that, increasing injection pressure have given that in engine performance is increased for indicated pressure(IP), indicated horse power (IHP), shaft horse power (SHP), break horse power (BHP) and break mean effective pressure (BMEP).