There is provided a degradation determining system for an exhaust gas sensor, which, even when unexpected changes occur in the air-fuel ratio during execution of air-fuel ratio control, can determine degradation of the sensor by suppressing adverse influen...

The method entails estimating the amount of air drawn into a cylinder based on an intake manifold pressure. The value of an identification parameter is determined using an adaptive observer. The estimated amount of air drawn into the cylinder and the value...

A vehicle controller for controlling the air-fuel ratio of an engine is provided. In one embodiment, the controller comprises a first exhaust gas sensor provided downstream of the catalyst for detecting oxygen concentration of exhaust gas, a first decimati...

A manipulation variable generating unit 7 for generating a target air-fuel ratio KCMD to converge the output of an oxygen concentration sensor 5 disposed downstream of a catalytic converter 3 in an exhaust system E as a plant to a given target value has a ...