Method and system for diagnosing deterioration of NOx catalyst
US6167695A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 12, 1999 |
| Grant date | Jan 2, 2001 |
| Priority date | — |
| Expiry date | Feb 12, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/40
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A system and method for diagnosing deterioration of a nitrogen oxide (NOx) catalyst for an internal combustion engine. An output signal indicative of concentration of nitrogen oxides (NOx) in exhaust gas passing through the NOx catalyst is generated from a NOx sensor. Rates of change in the detected NOx concentration are calculated a plurality of times over a predetermined period of time after an air/fuel ratio becomes less than a stoichiometric air/fuel ratio. A representative value derived from the calculated rates of change in the detected NOx concentration is compared with a predetermined reference value for determining that the NOx catalyst is deteriorated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.