Patent ID: 7845160

Claim:
A control device for an internal combustion engine, comprising: a catalyst provided in an exhaust system of the internal combustion engine, for cleaning an exhaust gas; a first air/fuel ratio sensor provided to an upstream side of the catalyst, for detecting an air/fuel ratio of the exhaust gas on the upstream side of the catalyst; a second air/fuel ratio sensor provided to a downstream side of the catalyst, for detecting an air/fuel ratio of the exhaust gas on the downstream side of the catalyst; a first air/fuel ratio feedback control means for controlling the air/fuel ratio of the exhaust gas on the upstream side of the catalyst based on an output value of the first air/fuel ratio sensor and a controlling constant group containing a plurality of controlling constants; a second air/fuel ratio feedback control means for calculating a target average air/fuel ratio corresponding to a target value of an average air/fuel ratio of the exhaust gas on the upstream side of the catalyst based on an output value of the second air/fuel ratio sensor and a predetermined output target value; and a conversion means for calculating at least two controlling constants of the controlling constant group by using the target average air/fuel ratio as a common index.