Control system for internal combustion engine

摘要

A control system for an internal combustion engine having an exhaust system provided with a catalyst is provided. The control system comprises a catalyst temperature rise accelerating control in which the intake air amount is increased and the ignition timing is retarded according to the engine rotational speed. A transient control from the catalyst temperature rise accelerating control to the normal control, is started when the speed of a vehicle driven by the engine reaches a predetermined vehicle speed or higher during the catalyst temperature rise accelerating control. During the transient control, the intake air amount is gradually reduced and the ignition timing is set according to the vehicle speed.