Patent ID: 6814067
Filing Date: 2004-11-09
Classification: F02D,G05B

Abstract:
An air-fuel ratio control system for an internal combustion engine, said air-fuel ratio control system comprising:identifying means for identifying model parameters of a controlled object model which is obtained by modeling said engine; an air-fuel ratio sensor provided in an exhaust system of said engine; and control means for controlling an air-fuel ratio of an air-fuel mixture to be supplied to said engine wherein the air-fuel ratio detected by said air-fuel ratio sensor coincides with a target value, said control means including self-tuning control input calculating means for calculating a self-tuning control input, using the model parameters identified by said identifying means; and damping control input calculating means for calculating a damping control input according to a rate of change in the detected air-fuel ratio or a rate of change in a deviation between the detected air-fuel ratio and the target value, wherein the air-fuel ratio of the air-fuel mixture to be supplied to said engine is controlled using the self-tuning control input and the damping control input.