| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for diagnosing deterioration of a three-way catalyst capable of accurately performing deterioration diagnosis of the three-way catalyst under a wide range of operation condition including acceleration operation zone. <P>SOLUTION: This method for diagnosing deterioration of the three-way catalyst is provided with a detector 3 capable of continuously measuring concentration of nitrogen oxide contained in combustion exhaust gas and/or air-fuel ratio of combustion exhaust gas in an upstream side and a downstream side of the three-way catalyst 2 in an exhaust gas flow passage 4, concentration of nitrogen oxide contained in combustion exhaust gas and/or air-fuel ratio of combustion exhaust gas in the upstream side and the downstream side of the three-way catalyst 2 in the exhaust gas flow passage 4 are acquired, degree of deterioration of the three-way catalyst 2 is diagnosed based on fluctuation of acquired concentration of nitrogen oxide and/or air-fuel ratio of combustion exhaust gas. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
