Ignition timing control apparatus for internal combustion engine

Abstract

An ignition timing control apparatus for an internal combustion engine comprises a pick-up incorporated in a distributor for detecting a crank angle, a circuit for producing a basic ignition timing indicating signal on the basis of the output signal from the pick-up, a knocking detection circuit for generating a knocking detection signal, a circuit responding to the knocking detection signal and the basic ignition timing indicating signal to generate an actual ignition command signal delayed by a predetermined crank angle from the basic ignition timing, and the control apparatus further includes a circuit responding to these three signals to inhibit the operation of the knocking detection circuit during a period beginning at a time point which precedes to the operation of an inlet valve and an exhaust valve of a cylinder another than the cylinder in concern and terminating at a time point at which a predetermined time has elapsed since the ignition of the cylinder in concern.