JP2844407B

Ignition timing control system for internal combustion engines. The system comprises a means for detecting operating parameters of the engine such as engine speed, engine load, the presence of knock, a means for determining a basic ignition timing on the basis of the engine speed and load, a means for determining a first group of retard amounts based on the detected operating parameters to prevent knock from occurring, and a means for determining a second group of retard amounts based on the detected operating parameters to intentionally reduce output torque of the engine. The first retard amount group is compared with the second one the basic ignition timing is corrected by the selected value. With the arrangement, the retard amount is limited to the minimum required even when engine operating conditions producing knock and requiring engine output reduction are present at the same time.