Misfire detection in an internal combustion engine using modified median averaging

摘要

The invention estimates baseline acceleration expected from normal (i. e., non-misfiring) cylinders in an internal combustion engine even when the misfire rate reaches 50%. An offset median value is used to derive an average or gross acceleration value to provide a baseline rather than a true median. The offset median is the next largest value greater than the true median, so that the presence of 50% misfires does not degrade the determination of the baseline.