Deterioration diagnostic system of exhaust gas purifying catalyst
US7739868B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 8, 2007 |
| Grant date | Jun 22, 2010 |
| Priority date | — |
| Expiry date | Feb 1, 2029 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/40
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
A deterioration diagnostic system of an exhaust gas purifying catalyst includes: an upstream side switching frequency calculator calculating the number of times of switching on the upstream side; a reference value calculator calculating a downstream side rich/lean determination level having a first width; a downstream side rich/lean determination level adjuster setting the first width to a second larger width when the number of times of switching on the upstream side is smaller than a predetermined value; a downstream side switching frequency calculator calculating the number of times of switching on the downstream side; a frequency ratio calculator calculating a frequency ratio between the number of times of switching on the downstream side and the number of times of switching on the upstream side; and a deterioration determiner determining the deterioration of the exhaust gas purifying catalyst when the frequency ratio is larger than a predetermined value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.