Misfire detection system and method of median filtering

摘要

A processor having an embedded median filter routine, a method of median filtering using a vehicle's CPU, and a misfire detection system for an internal combustion engine with crankshaft acceleration detection means for determining crankshaft acceleration values. In general, the processor is configured to receive new acceleration values and includes a data structure with a data array containing a predetermined number of data fields storing acceleration values in magnitude order. The embedded median filtering routine is configured to identify an oldest in time acceleration value, identify a deletion position in the data array for the oldest in time acceleration value, identify an insertion position in the data array, move selected acceleration values in the data array to vacate the insertion position, insert the new acceleration value in the insertion position, and determine the median value of the acceleration values in the data array.