发明名称 |
A device for determining deterioration of a catalyst for an engine |
摘要 |
<p>A device for determining deterioration of a catalyst having an O2 storage capability and disposed in an exhaust passage of an engine comprises: upstream and downstream air-fuel ratio sensors disposed in the exhaust passage upstream and downstream of the catalyst respectively for detecting air-fuel ratios of exhaust gas upstream and downstream of the catalyst. The air-fuel ratio of the exhaust gas flowing into the catalyst is controlled on the basis of the output of the upstream air-fuel ratio sensor to make the air-fuel ratio flowing into the catalyst a target air-fuel ratio. A ratio of the length of the response curve of the output of the downstream air-fuel ratio sensor to the length of the response curve of the output of the upstream air-fuel ratio sensor is calculated. A ratio of the frequency of the output of the downstream air-fuel ratio sensor to the frequency of the output of the upstream air-fuel ratio sensor is calculated. It is determined that the catalyst has deteriorated when the length ratio is greater than a first predetermined ratio, or when the length ratio is greater than a second predetermined ratio which is smaller than the first predetermined ratio and the frequency ratio is greater than a third predetermined ratio. <IMAGE></p> |
申请公布号 |
EP0823546(A1) |
申请公布日期 |
1998.02.11 |
申请号 |
EP19970113778 |
申请日期 |
1997.08.08 |
申请人 |
TOYOTA JIDOSHA KABUSHIKI KAISHA |
发明人 |
SAWADA, HIROSHI |
分类号 |
G01M15/04;F01N3/20;F01N11/00;F02B77/08;F02D41/14;F02D45/00;(IPC1-7):F01N7/00 |
主分类号 |
G01M15/04 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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