Deterioration diagnosing device and diagnosing method for exhaust gas purification catalyst
US7325393B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Feb 17, 2005 |
| Grant date | Feb 5, 2008 |
| Priority date | — |
| Expiry date | May 13, 2025 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/40
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
To determine whether an exhaust gas purification catalyst (42) of an engine (1) has deteriorated, a characteristic of exhaust gas on an upstream side of the catalyst (42) is detected, a characteristic of the exhaust gas on a downstream side of the catalyst (42) is detected, and when the engine (1) operates at a lean air-fuel ratio, a value expressing a difference in the oxygen concentration on the upstream side and downstream side of the catalyst (42) (an average excess air ratio difference) is calculated from the two detected values. When the value expressing the difference in the oxygen concentration is smaller than a deterioration determination threshold calculated in accordance with a quantity of state of the catalyst (42), the catalyst (42) is determined to have deteriorated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.