Misfire detector measuring spark duration - is used in IC engine and compares duration deduced from detection of ignition coil prim. and sec. voltages with predetermined reference interval

摘要

Thr prim. winding (21a) of the ignition coil (21) is switched (T2) by a bipolar transistor (22), producing a sec. pulse for the sparking plug (23). Voltages at the collector electrode (N1) and the central electrode (N2) of the plug are taken through 1000:1 and 100:1 dividers (24,25), filters (26, 28) and digitisers (27,29) to a processor (5b). Inputs (5a) from detectors of engine speed and inlet manifold absolute pressure control the prodn. of an ignition command signal (A). The spark duration is compared with a min. reference. USE/ADVANTAGE - The site of a misfire can be detected precisely and promptly for instigation of suitable countermeasures.