CORRECTION DEVICE FOR AIR/FUEL RATIO SENSOR

摘要

This correction device for an air/fuel ratio sensor has the following: an air/fuel ratio control means that controls the air/fuel ratio of exhaust gas upstream of a catalyst (6) seated in the exhaust passage of an internal combustion engine so as to switch between a rich air/fuel ratio and a lean air/fuel ratio, which respectively are richer and leaner than the stoichiometric air/fuel ratio; and an air/fuel ratio sensor (12) that generates output in accordance with the air/fuel ratio of the exhaust gas downstream of the catalyst (6) in the exhaust passage. A correction-coefficient computation means is also provided. When the air/fuel ratio control means is controlling the air/fuel ratio, said correction-coefficient computation means computes a correction coefficient for correcting the output from the air/fuel ratio sensor (12). Said computation is performed in accordance with the discrepancy between a reference output, said reference output corresponding to the stoichiometric air/fuel ratio, and the output of the air/fuel ratio sensor (12) over a prescribed period over which said output reaches equilibrium.