AIR-FUEL RATIO CONTROL SYSTEM

摘要

An air-fuel ratio control system for an internal combustion engine has an electromagnetic valve for correcting the air-fuel ratio of air-fuel mixture, an O2 sensor for detecting oxygen concentration in exhaust gases, and a feedback control circuit including a pulse generating circuit for generating pulses, the duty ratio of which is dependent on the oxygen concentration. The system has an engine deceleration detecting circuit and a light load detecting circuit for producing a deciding signal. Pulses having a fixed duty ratio are applied to the electromagnetic valve in response to the deciding signal so as to enrich the air-fuel mixture at the deceleration when the throttle valve closes.