Electronic control system for carburetor and control method therefor

摘要

A control system for an electronically controlled carburetor operative during engine start-up employs an oxygen-concentration (O2) sensor which is accurate only a given engine temperature range. Engine temperature in the vicinity of the O2 sensor is compared to a predetermined threshold to determine whether the O2 sensor is sufficiently warm. When the O2 sensor is cold, the carburetor is controlled via an OPEN LOOP method wherein the carburetor is operated at a constant state so as to produce a predetermined constant air/fuel mixture. When the O2 sensor is warm, its output is processed to determine whether the air/fuel mixture is too rich or too lean as part of a CLOSED LOOP control method in which carburetor operation is adjusted in order to correct the air/fuel ratio in accordance with the output of the O2 sensor.