Patent ID: 7784271
Filing Date: 2010-08-31
Classification: F01N,F02D,Y02T

Abstract:
1. An apparatus for detecting deterioration of a catalyst provided in an exhaust system of an internal-combustion engine, the apparatus comprising: air-fuel ratio sensors provided in the upstream side and the downstream side of the catalyst for measuring air-fuel ratio in the exhaust gas; means for changing the air-fuel ratio in the exhaust gas; means for identifying a parameter β of a catalyst model representing deterioration state of the catalyst in accordance with variation of the air-fuel ratio in the upstream side and the downstream side of the catalyst as measured by the air-fuel ratio sensors when the air-fuel ratio is changed, wherein parameter β is identified by minimizing an error function S  wherein n is a number of measured samples of the upstream air-fuel ratio X and the downstream air-fuel ratio Y; and means for determining a state of the catalyst based on the identified parameter.