Patent ID: 8434455
Filing Date: 2013-05-07
Classification: F02D

Abstract:
1. A control system for an internal combustion engine, which includes intake air flow rate control means for controlling an intake air flow rate of said engine, and performs an engine output control so that an output of said engine coincides with a demand output by changing at least one of the intake air flow rate and an ignition timing of said engine, said control system comprising: output reduction control means for performing 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, when the demand output decreases; retard limit calculating means for calculating a retard limit of the ignition timing according to an operating condition of said engine; retard limit output calculating means for calculating a retard limit output which is an output of said 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; and retard limit intake air flow rate calculating means for calculating a retard limit intake air flow rate when the demand output is less than the retard limit output, the retard limit intake air flow rate being an intake air flow rate at which the engine output is equal to the demand output under the condition where the ignition timing is retarded to the retard limit, wherein said output reduction control means makes the engine output coincide with the demand output by retarding the ignition timing, when the demand output is equal to or greater than the retard limit output, and said output reduction control means retards the ignition timing to the retard limit and controls said intake air flow rate control means so that the intake air flow rate coincides with the retard limit intake air flow rate, when the demand output is less than the retard limit output.