Method and device for feedback controlling air-fuel ratio of internal combustion engine

摘要

An air-fuel ratio detected by an air-fuel ratio sensor is estimated based on an estimation value of air-fuel ratio of an air-fuel mixture formed inside a cylinder, and based on an air-fuel ratio estimated as being detected by this air-fuel ratio sensor and the air-fuel ratio detected based on an output signal of the air-fuel ratio sensor, the estimation value of the cylinder air-fuel ratio is corrected and a fuel injection quantity is corrected based on the corrected cylinder air-fuel ratio.