Air / fuel - ratio of expensive system for internal combustion engine with the ability of a an attitude responsive factor correction coefficient containing to learn.

摘要

An air/fuel ratio control system controls fuel delivery amount on the basis of oxygen concentration in an exhaust gas. An air/fuel ratio dependent correction value is derived on the basis of the oxygen concentration. The air/fuel ratio control is performed in feedback mode and open loop mode. In feedback mode, fuel delivery amount is corrected utilizing a correction value which includes a learnt component. Learning of the learnt component is performed during feedback mode operation. The learnt component comprises an uniformly applicable air density dependent factor and a engine driving range dependent factor which is set with respect to each of the engine driving ranges. Learning of the air density factor and engine driving range dependent factor are selectively performed depending upon the engine driving condition.