Patent ID: 9273593
Filing Date: 2016-03-01
CPC Classification: F01N,F02B,F02D,Y02T

Claim Text:
1. A control apparatus for an internal combustion engine, comprising: an exhaust purification catalyst that is provided in an exhaust passage of the internal combustion engine and that has an oxygen storage capability; a turbo-supercharger that has a turbine that is provided in the exhaust passage on an upstream side of the exhaust purification catalyst, and that supercharges intake air utilizing an exhaust pressure; a bypass passage that branches from the exhaust passage on an upstream side of the turbine, and bypasses the turbine and merges with the exhaust passage on the upstream side of the exhaust purification catalyst; a waste gate valve that adjusts an amount of exhaust gas that flows through the bypass passage; air-fuel ratio detection unit that is arranged on a downstream side of a merging position where the exhaust passage and the bypass passage merge, and that detects an air-fuel ratio in a vicinity of the exhaust purification catalyst; active air-fuel ratio control unit that alternately changes a target air-fuel ratio to a rich side and a lean side around a theoretical air-fuel ratio, and controls an actual air-fuel ratio that is detected by the air-fuel ratio detection unit so that the actual air-fuel ratio matches the target air-fuel ratio; deterioration determination unit that measures an oxygen storage capacity of the exhaust purification catalyst based on the target air-fuel ratio and the actual air-fuel ratio in a state in which the actual air-fuel ratio is controlled by the active air-fuel ratio control unit, and determines deterioration of the exhaust purification catalyst by comparing a relevant measurement value of the oxygen storage capacity with a predetermined deterioration determination value; and amplitude correction unit that, when the deterioration determination unit determines the deterioration of the exhaust purification catalyst, corrects an oscillation width of the target air-fuel ratio around the theoretical air-fuel ratio based on a degree of opening of the waste gate valve.