Patent ID: 7623954

Claim:
An air-fuel ratio control apparatus of an internal combustion engine, comprising: an air-fuel ratio sensor capable of detecting a stoichiometric air-fuel ratio and provided in an exhaust gas passage of an engine; and a controller selectively performing an air-fuel ratio feedback control to bring an air-fuel ratio of the engine toward a target air-fuel ratio on the basis of an output from the air-fuel ratio sensor, in which the target air-fuel ratio is a rich air-fuel ratio when the engine is operated in a rich operational region where fuel supply to the engine is increased, the air-fuel ratio feedback control being performed with a feedback coefficient for selectively bringing the air-fuel ratio toward the target air-fuel ratio and performed by selectively limiting the feedback coefficient at a limit value, in which the limit value used in the rich operational region is determined such that the feedback coefficient is generally limited as compared to a limit value used in an operational region other than the rich operational region.