Ignition advance angle controlling device

摘要

A knocking sensor output signal of an ignition advance angle controlling device is subdivided in synchronism with the engine rotation into a knocking portion and a background portion. Both signal portions are rectified and averaged and the averaged portions are compared to derive a difference signal. The ignition advance angle is controlled to advance or to retard in response to said difference signal so as to obtain an optimum control of the advance angle in response to the amount of knocking.