System for controlling ignition timing in an internal combustion engine and method therefor

摘要

A system and method for controlling ignition timing of an internal combustion engine controls the ignition timing in accordance with the measured intensity of knocking when such occurs. The system corrects the ignition timing by a retardation amount related to the intensity of knocking. The system monitors engine vibration over a period in which knocking cannot occur and over the period after TDC in which knocking may occur and compares the vibration intensity levels to produce a statistical measure of knocking intensity. If the measured intensity reflects a high probability of severe knocking, ignition is retarded immediation to an extent related to the measured intensity. If knocking is absent to a high probability, ignition timing is advanced to a fixed extent. When only light knocking is detected, the measured intensity is monitored over numerous ignition cycles until the cumulative intensity level reflects a high probability either of desirable trace knocking or moderately disruptive knocking. In the latter case, ignition is retarded to a fixed extent.