Ignition timing correcting system for internal combustion engine

摘要

An ignition timing correcting system generates a reference timing signal at a reference angular position of a rotating internal combustion engine and a ignition timing signal leading it by a constant phase. The latter signal is controllably retarded in phase to form a retarded ignition timing signal. The phase comparison of the two signals produces an advance or a retardation correcting signal formed of a pulse train having a pulse width corresponding to the phase difference between them. During the idling of the engine, the correcting signal drives a reversible motor forwardly or reversely to move a movable top on a potentiometer to adjust a control signal provided from the latter. When the pulse width becomes sufficiently narrow, the correcting signal is disabled to drive the motor resulting in the required control signal. That control signal corrects the retardation of the retarded ignition timing signal to a regular ignition timing.