Patent ID: 6195988
Filing Date: 2001-03-06
Classification: F02D

Abstract:
An air-fuel ratio control system for an internal combustion engine, comprising:an exhaust gas sensor for detecting the concentration of a component of an exhaust gas which has passed through a catalytic converter disposed in an exhaust passage of the internal combustion engine, said exhaust gas sensor being disposed downstream of said catalytic converter;manipulated variable generating means for sequentially generating a manipulated variable for manipulating the air-fuel ratio of an air-fuel mixture to be combusted by the internal combustion engine in order to converge an output of said exhaust gas sensor to a predetermined target value;air-fuel ratio manipulating means for manipulating the air-fuel ratio of the air-fuel mixture based on the manipulated variable generated by said manipulated variable generating means;the arrangement being such that a system for generating the output of said exhaust gas sensor from said manipulated variable via said manipulated variable generating means, the internal combustion engine, and the catalytic converter is regarded as an object system, and the object system including an element relative to a response delay of the object system is expressed as a model by a discrete-time system; andidentifying means for sequentially identifying a parameter to be established of the model using data of the manipulated variable generated by said manipulated variable generating means and data of the output of said exhaust gas sensor;said manipulated variable generating means comprising means for generating said manipulated variable according to a feedback control process constructed based on said model using the parameter of the model identified by said identifying means and the data of the output of said exhaust gas sensor.