Catalyst deterioration detecting apparatus and method
US7198952B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 15, 2002 |
| Grant date | Apr 3, 2007 |
| Priority date | — |
| Expiry date | Dec 9, 2023 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T436/25875
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
An upstream side catalyst and a downstream side catalyst are disposed in an exhaust passage. A first oxygen sensor is disposed between these two catalysts and a second oxygen sensor is disposed downstream of the downstream side catalyst. The air-fuel ratio is forcibly oscillated and the oxygen storage capacity of the upstream side catalyst is detected. Deterioration of the upstream side catalyst is then detected based on whether this oxygen storage capacity is larger than a predetermined value. The forced oscillation of the air-fuel ratio is performed only when the oxygen storage state of the downstream side catalyst is appropriate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.