Catalyst degradation determining method
US6915628B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 26, 2003 |
| Grant date | Jul 12, 2005 |
| Priority date | — |
| Expiry date | Jun 26, 2023 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/40
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
A catalyst degradation determining method includes the steps of: controlling an upstream-of-catalyst air-fuel ratio occurring upstream of a first catalyst to an air-fuel ratio that is rich of a stoichiometric air-fuel ratio so that first and second catalysts store oxygen up to a maximum storage amount of oxygen. The method then includes the steps of controlling the upstream-of-catalyst air-fuel ratio to a first lean air-fuel ratio until an output of a downstream-of-first-catalyst sensor indicates a lean air-fuel ratio, and then to a second lean air-fuel ratio and that has a value that is determined in accordance with an oxidizing-reducing capability index value, until a time point when an output of a downstream-of-second-catalyst air-fuel ratio sensor indicates an air-fuel ratio that is lean.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.