INTERNAL COMBUSTION ENGINE CONTROLLER

The internal combustion engine comprises an exhaust purification catalyst (20) able to store oxygen, and a downstream side air-fuel ratio sensor (41) arranged at a downstream side of the catalyst The system performs feedback control of an amount of fuel fed to a combustion chamber so that an air-fuel ratio of exhaust gas flowing into the catalyst becomes a target air-fuel ratio and performs learning control to correct a parameter relating to the feedback control based on an air-fuel ratio of exhaust gas detected by the sensor. The target air-fuel ratio is alternately switched between a rich set air-fuel ratio and a lean set air-fuel ratio. When a condition for learning acceleration is satisfied, a rich degree of the rich set air-fuel ratio is increased. It is provided an engine able to suitably change the speed of updating the learning value.