Air-fuel ratio control system based on adaptive control theory for internal combustion engines

摘要

An air-fuel ratio control system for an internal combustion includes an air-fuel ratio sensor arranged in the exhaust system, and an ECU which controls an amount of fuel to be supplied to the engine in a feedback manner based on an output from the air-fuel ratio sensor by using an adaptive controller of a recurrence formula type, such that the air-fuel ratio of an air-fuel mixture supplied to the engine becomes equal to a desired air-fuel ratio. Deterioration of a response characteristic of the air-fuel ratio sensor is detected based on at least one adaptive parameter used in the feedback control of the amount of fuel to be supplied to the engine.