METHOD OF DETECTING MISFIRE BY UTILIZING VARIATION OF ROTATION OF CRANKSHAFT.

摘要

A method of detecting misfire by utilizing the variation of rotation of a crankshaft, capable of detecting the occurrence of misfire accurately with the influence of a detection error eliminated which is ascribed to a structural error of a crank angle sensor used in the detection of variation of rotation of the crankshaft. When a processor receives pulses sequentially from a crank angle sensor, it detects (S2) the length of a period of time between the entry of the detection operation into a region of angle of rotation of crankshaft concerning a cylinder corresponding to the two pulses and the departure of the same operation from the same region. An angular acceleration D omega n of the crankshaft is calculated (S3, S4) by using a correction factor which is determined on the basis of this detected length of period of time and the length of period of time which is free from an error of operation of the sensor and determined by dividing the time required for one turn of the crankshaft by the number of the cylinders. When a calculated value D omega n is smaller than a judgement value, the occurrence of misfire is detected (S5-S7).