Control system for internal combustion engine

A control system for an internal combustion engine in a vehicle having an exhaust system provided with a catalyst, comprising:

• intake air amount control means for controlling the intake air amount of the engine;
• ignition timing control means for controlling the ignition timing of the engine;
• and
• catalyst temperature rise accelerating means for increasing, after starting of the engine, the intake air amount and retarding the ignition timing according to the engine rotational speed;
• wherein said catalyst temperature rise accelerating means starts reduction of the intake air amount when the speed of the vehicle reaches a first predetermined vehicle speed or higher during operation of said catalyst temperature rise accelerating means, and ends retard control of the ignition timing according to the engine rotational speed when the vehicle speed reaches a second predetermined vehicle speed higher than the first predetermined vehicle speed, and said catalyst temperature rise accelerating means changes the retard limit value of the ignition timing according to the vehicle speed when the vehicle speed is between the first predetermined vehicle speed and the second predetermined vehicle speed.