Closed loop mixture control system using a two-barrel carburetor

摘要

A closed loop mixture control system for an internal combustion engine includes a two-barrel carburetor having a primary throttle and a secondary throttle which is adapted to be automatically brought into action when the primary venturi depression reaches a predetermined value. An exhaust composition sensor is provided to control the air-fuel ratio through the primary barrel so that the conversion efficiency of a catalytic convertor is at a maximum during the time prior to the operation of the secondary throttle.