Patent attributes
A control apparatus for an internal combustion engine has an oxygen storage volume computing unit for computing an oxygen storage volume of a catalyst by using a real air/fuel ratio detected by an air/fuel ratio sensor installed on the upstream side of a catalyst, a center air/fuel ratio representing a stoichiometric air/fuel ratio and an estimated air flow volume or detecting a flow rate of air flowing into the catalyst. A center air/fuel ratio correcting unit for correcting a center air/fuel ratio based on output of a rear air/fuel ratio sensor provided on the downstream side of the catalyst, and an oxygen storage volume computed by an oxygen storage volume computing unit, and the oxygen storage volume computing unit computes an oxygen storage volume by using a center air/fuel ratio corrected by the center air/fuel ratio correcting unit.
