What is the significance of the mean arterial pressure?

What is the significance of mean effective pressure?

• Answer:

  Edit: The mean effective pressure is a quantity related to the operation of an reciprocating engine and is a valuable measure of an engine's capacity to do work that is independent of engine displacement. Mean Effective Pressure (MEP) is a fictitious pressure, such that if it acted on the piston during the entire power stroke, it would produce the same amount of net work. The concept of mean effective pressure is useful for real compressors as the power input to the compressor is a product of mep and the swept volume rate. When quoted as an indicated mean effective pressure or IMEP, it may be thought of as the average pressure over a cycle in the combustion chamber of the engine. When tuning a 4-stroke internal combustion engine, it’s important to understand how much theoretical pressure is being exerted on the top of the piston during the power stroke. This information is useful as a comparison tool between different engines, and provides a good indicator of what performance levels can be achieved from different setups. During normal engine operation, when a piston’s compressed air/fuel mixture is ignited during the power stroke, the resultant combustion exerts pressure on the top of the piston. Since this pressure ultimately results in the movement of the piston itself, we can consider it as being correlated to the power output of the engine. The average (mean) theoretical piston-top pressure that would result in the measured power output of an engine is referred to as the “Mean Effective Pressure”, and is an important value to consider when analyzing an engine.