Air/fuel mixture ratio control system in internal combustion engine with _engine operation range dependent _optimum correction coefficient learning feature

摘要

An air/fuel ratio control system employs an altitude dependent learnt uniform correction coefficient which is applicable for all engine driving range and another engine driving range based correction coefficient learnt with respect to responsive engine driving range. The uniform correction coefficient is cyclically updated on engine driving range based correction coefficient. The control system performs FEEDBACK mode air/fuel ratio control with the learnt uniform correction coefficient and the engine driving range based correction coefficient. On the other hand, the control system performs OPEN LOOP mode air/fuel ratio control with the learnt uniform correction coefficient.