Method and system for controlling engine ignition timing

摘要

A method and system for correcting engine ignition timing without the use of any pressure sensor or vibration sensor and depending upon engine knocking is disclosed. The presence or absence of knocking is determined by reference to the rate of change of engine speed. This method is based on the fact that engine speed changes abruptly when engine knocking occurs, as compared with the normal engine condition, because of abrupt changes in pressure within the cylinders. The system of the present invention comprises an crankshaft angle sensor to generate a crankshaft angle pulse signal, a period measuring means to output an interrupt request signal and to determine the presence or absence of engine knocking, a microcomputer, and an ignition signal generator for outputting an ignition signal in accordance with an ignition timing signal and a dwell angle signal.