Air-fuel ratio control system for automotive engines

摘要

An air-fuel ratio control system for an engine has integrating means for integrating an error signal which is the difference between a reference voltage and an output voltage of an O2-sensor and for producing an integration signal. In response to the integration signal, the air-fuel ratio is controlled to a desired value. When fuel vapor in a canister of the engine is purged, an integration constant of the integrating means is increased for a predetermined time in order to allow a deviation of the air-fuel ratio to quickly converge.