Method and apparatus for controlling the air-fuel ratio in internal combustion engine.

摘要

In an internal combustion engine, when the opening of a throttle valve is smaller than a relatively small definite value, the feedback of the air-fuel ratio of the engine is controlled so that the air-fuel ratio is brought close to a first aimed air-fuel ratio. When the opening of the throttle valve is equal to or larger than a relatively small definite value and is smaller than a relatively large definite value, the feedback of the air-fuel ratio of the engine is controlled so that the air-fuel ratio is brought close to a second aimed air-fuel ratio on the rich side with respect to the first aimed air-fuel ratio. Further, when the opening of the throttle valve is equal to or larger than the relatively large definite value, the air-fuel ratio of the engine is controlled to be a power fuel increment air-fuel ratio.