Abstract
The calculation error of IMEP depends on the number n of sampling pressure data and increases with decreasing n. It is also affected by numerical integration methods. In this study, the influences on the error are tested with continuous pressure data. The error of the proposed IMEP equation based on the Fourier series expansion is similar to that of Trapezoid rule and smaller than that of conventional method and Simpson's rule. Correlation coefficient is 0.99, even if n decreases to eighteen per cycle. The equation has advantage on calculation time as compared with Trapezoid rule and then can be recognized to be excellent more method.
