AIR/FUEL RATIO FEEDBACK CONTROL SYSTEM ADAPTED TO OBTAIN STABLE ENGINE OPERATIONS UNDER PARTICULAR ENGINE OPERATING CONDITIONS

摘要

TITLE OF THE INVENTIONAIR/FUEL RATIO FEEDBACK CONTROL SYSTEMADAPTED TO OBTAIN STABLE ENGINE OPERATIONUNDER PARTICULAR ENGINE OPERATING CONDITIONSABSTRACT OF THE DISCLOSUREAn air/fuel ratio feedback control system adapted tocontrol the air/fuel ratio of an air/fuel mixture beingsupplied to an internal combustion engine, by the use ofa first coefficient having a value variable in response toactual exhaust gas concentration and at least one secondcoefficient having a value variable in dependence on thekind of a particular operating condition or region in whichthe engine is operating. The control system is operablesuch that when the engine is operating in an operating con-dition other than predetermined particular operating condi-tions of the engine, the value of the first coefficient isvaried in response to the output of an exhaust gas concen-tration sensor, and simultaneously the value of the secondcoefficient is held at a first predetermined value, andwhen the engine is operating in one of the predeterminedparticular operating conditions, the value of the secondcoefficient is held at a second predetermined value, andsimultaneously the value of the first coefficient at a thirdpredetermined value which is a mean value of values of thefirst coefficient obtained when the engine is operating inthe above operating condition other than the particularoperating conditions.