Air-fuel ratio control system

摘要

An air-fuel ratio control system for an internal combustion engine having an emission control system with a three-way catalytic converter for controlling the air-fuel ratio in accordance with the operation of the engine. A throttle sensor for detecting a wide-open throttle operation of the engine and a predetermined voltage supply circuit are provided. A feedback control circuit is provided for controlling the air-fuel ratio to the stoichiometric air-fuel ratio in a normal operating condition. A memorizer circuit memorizes a value corresponding to the control output of the feedback control circuit. A first switch means is actuated by the output of the throttle senor to connect the output of the predetermined voltage supply circuit with the input of the feedback control circuit when acceleration is detected, and to cut off the input of the memorizer circuit for maintaining the stored content thereof. A second switch circuit actuated by the output of the throttle sensor to render the feedback control circuit inoperative as a feedback controller, whereby the air-fuel ratio is controlled by the output of the predetermined voltage supply circuit. After the wide-open throttle operation, the feedback control circuit re-starts with the stored content in the memorizer circuit.