Patent ID: 6055844
Filing Date: 2000-05-02
Classification: F01N,F02D

Abstract:
An internal combustion engine air/fuel ratio detection device comprising:an air/fuel ratio detection means for detecting the air/fuel ratio of an air/fuel mixture supplied to an internal combustion engine, based on output transmitted from a stoichiometric air/fuel ratio sensor having an output rapidly changing when proximate a desired air/fuel ratio; andan air/fuel ratio control means for adjusting the air/fuel mixture to control the air/fuel ratio, whereinwhen the air/fuel ratio is controlled to be richer than the stoichiometric air/fuel ratio during engine operation, said air/fuel ratio control means is operated, temporarily making the air/fuel ratio leaner than the stoichiometric air/fuel ratio, said air/fuel ratio detection means detects a lean output time, and a proper air/fuel ratio for said engine operation is obtained based on the lean output time.