Abstract: A control system for an internal combustion engine having a plurality of cylinders including first and second cylinder groups. The first and second intake systems correspond respectively to the first and second cylinder groups, and first and second throttle valves are provided respectively in the first and second intake systems. An output of the engine is reduced upon deceleration of a vehicle driven by the engine. A pressure parameter indicative of an assisting force generated by a brake booster is detected. An intake negative pressure is supplied to the brake booster from the first and second intake systems. One of the first and second throttle valves is opened to increase the engine output when the pressure parameter is equal to or less than a first threshold value which indicates that the assisting force of the brake booster has decreased.

Abstract: A control system for an internal combustion engine performs output control so that an engine output coincides with demand output by changing intake air flow rate or ignition timing of the engine. Output reduction control, wherein engine output is reduced, is performed when the demand output decreases. A retard limit output is calculated, and a retard limit intake air flow rate is calculated when the demand output is less than the retard limit output. The engine output is made to coincide with the demand output by retarding the ignition timing when the demand output is equal or greater than the retard limit output. When the demand output is less than the retard limit output, the ignition timing is retard to the limit and the intake air flow rate is controlled so as to coincide with the retard limit intake air flow rate.

Abstract: A control system for an internal combustion engine having a plurality of cylinders including first and second cylinder groups. The first and second intake systems correspond respectively to the first and second cylinder groups, and first and second throttle valves are provided respectively in the first and second intake systems. An output of the engine is reduced upon deceleration of a vehicle driven by the engine. A pressure parameter indicative of an assisting force generated by a brake booster is detected. An intake negative pressure is supplied to the brake booster from the first and second intake systems. One of the first and second throttle valves is opened to increase the engine output when the pressure parameter is equal to or less than a first threshold value which indicates that the assisting force of the brake booster has decreased.

Abstract: A control system for an internal combustion engine which performs an engine output control so that an output of the engine coincides with a demand output by changing at least one of the intake air flow rate and an ignition timing of the engine. An output reduction control in which the engine output is reduced by changing at least one of the intake air flow rate and the ignition timing, is performed when the demand output decreases. A retard limit of the ignition timing is calculated according to an operating condition of the engine. A retard limit output, which is an output of the engine corresponding to a state where the ignition timing is retarded to the retard limit and the intake air flow rate is maintained at a value immediately before the demand output decreases, is calculated. A retard limit intake air flow rate is calculated when the demand output is less than the retard limit output.