Air-fuel ratio control apparatus of internal combustion engine and method thereof

摘要

The present invention is constituted so that an actual air-fuel ratio is detected by an air-fuel ratio sensor, a plant model representing a plant between a fuel injection valve and the air-fuel ratio sensor is sequentially identified to calculate parameters of the plant model, a control gain for calculating a feedback control amount is calculated using the calculated parameters, and the feedback control amount is calculated using the calculated control gain, wherein an absolute value of an input side parameter set on an input side of the plant model is limited to be a predetermined limit value or above, among the calculated parameters.