COMBINATION OF AIR-FUEL RATION CONTROL SYSTEM AND FUEL COMBUSTION MECHANISM AND METHOD OF CONTROLLING AIR-FUEL RATIO

摘要

A method for controlling the air- to-fuel ratio of the mixture fed to an engine or other combustion device has the air-to-fuel ratio periodically altered towards stoichiometric into the response range of a conventional exhaust gas sensor. The output of the sensor at stoichiometric establishes a reference point setting of the air-to- fuel ratio proportioning device (e.g., carburetor) whose adjusting element is then moved a selected distance away from its setting point to provide a selected value of air fuel ratio which may be outside the normal response range of the sensor, either rich or lean of stoichiometric. The apparatus described includes a sensor 181 which generates an output signal which is compared against a reference signal by a comparator 28. When the output signal exceeds (or falls below) the reference signal, a timer B allows the proportioning device 42 adjusting element to be moved in the desired direction for a stated interval of time. A separate timer A operates the adjusting element towards stoichiometric at selected intervals to periodically establish the reference point setting. IMAGE