AIR-FUEL RATIO CONTROL DEVICE OF INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide an air-fuel ratio control device of an internal combustion engine capable of restraining the deterioration in an emission characteristic in a failure diagnostic period of an exhaust gas sensor. SOLUTION: Execution of main FB control is prohibited in a failure diagnostic period of an air-fuel ratio sensor (104). Next, a correction injection quantity KApre just before impressing reverse voltage is acquired (106). A correction injection quantity KB in the failure diagnostic period is calculated by increasingly correcting this correction injection quantity KApre so that the exhaust air-fuel ratio becomes the rich side a little more than the stoichiometric air-fuel ratio (108). The final injection quantity injected from an injector is determined by adding the correction injection quantity KB to a base injection quantity (110). COPYRIGHT: (C)2008,JPO&INPIT