Although the BMEP can be obtained from the engine torque, the peak pressures occurring during combustion are much higher and are more difficult to obtain by calculation. As a starting point for calculations it is reasonable to use typical peak values, based on 'indicator diagrams' that can be found in some texts (e.g: ref. 1 and 2). The values below assume that the engine is operating at 'wide open throttle' (WOT).
Four stroke diesel engine: 5 - 7 MPa.
Two stroke petrol engine: 1.5 MPa.
Four stroke petrol engine: 2 - 5 MPa.
1. 'The Motor Vehicle', K Newton, W Steeds, T K Garrett, Butterworth Group, 9th ed. 1972.
2. 'Engines, an Introduction', by J L Lumley, Cambridge University Press, 1999, ISBN: 0-521-64489-5.
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David J Grieve, Revised 17th January 2008. Original 30th January 2003.