Misfire detection system for IC engine - has monitor detecting variations in engine speed during firing cycles and providing correction for uneven running from mechanical effects.

摘要

The engine speed is monitored by one sensor (3) and a processing control (53) computes the variation in engine speed during a firing cycle for each cylinder, or for a set period before and after TDC for each cylinder. The deviations from a constant speed are corrected by a smoothing operation which eliminates effects from mechanical variations. The smoothed values of the deviation are compared with reference levels to identify misfires. The rate of misfires is monitored by a memory. When a set number of misfires occurs in a particular cylinder a warning is operated or remedial action initiated. ADVANTAGE - Accurate determination of misfires; self-correcting for uneven engine running.