Deterioration detecting apparatus for catalyst
US7677027B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 2007 |
| Grant date | Mar 16, 2010 |
| Priority date | — |
| Expiry date | Sep 4, 2028 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/40
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
A deterioration detecting apparatus for a purifying catalyst in an exhaust system of an engine. A first oxygen concentration sensor is disposed upstream of the catalyst. A second oxygen concentration sensor is disposed downstream. An amount of oxygen flowing into the catalyst is calculated from the oxygen concentration detected by the first sensor and the detected intake air flow rate. A control command value of an air-fuel ratio is alternately switched between a first value corresponding to a lean air-fuel ratio and a second value corresponding to a rich air-fuel ratio according to a result of comparison between the calculated inflowing oxygen amount and target values. Excessive inflowing oxygen amounts are calculated. The target values are corrected with the excessive inflowing oxygen amount. A deterioration degree of the catalyst is detected based on an output of the second sensor when performing the switching of the control command value using the corrected target values.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.