AIR-FUEL RATIO CONTROL DEVICE OF INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To accurately control air-fuel ratio by correcting the output of an air-fuel ratio sensor according to the output of an oxygen sensor on the downstream side of a three-way conversion catalyst device in an air-fuel ratio control device of an internal combustion engine controlling a combustion air-fuel ratio to a desired air-fuel ratio according to the output of the air-fuel ratio sensor on the upstream side of the three-way conversion catalyst device. SOLUTION: During the operation in which a target air-fuel ratio is a theoretical air-fuel ratio, the output of the air-fuel ratio sensor 2 is corrected by an integral term based on the cumulative value of the deviations of the outputs of the oxygen sensor 3 from the theoretical air-fuel ratio. The integral term is updated for each update time. A fuel-cut prohibition period during which the operation in which the target air-fuel ratio is used as the theoretical air-fuel ratio is continued until the integral term is updated at least one time is formed in the air-fuel control device. COPYRIGHT: (C)2007,JPO&INPIT