Exhaust gas purification device for an engine
US5433074A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 26, 1993 |
| Grant date | Jul 18, 1995 |
| Priority date | — |
| Expiry date | Jul 26, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/40
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
An engine comprising an exhaust passage having therein a NO.sub.x absorbent which absorbs the NO.sub.x when the air-fuel ratio of the exhaust gas flowing into the NO.sub.x absorbent is lean and releases the absorbed NO.sub.x when the air-fuel ratio of the exhaust gas flowing into the NO.sub.x absorbent becomes the stoichiometric air-fuel ratio or rich. A catalyst having an O.sub.2 storage function is arranged in the exhaust passage downstream of the NO.sub.x absorbent. When NO.sub.x is to be released from the NO.sub.x absorbent, the air-fuel ratio of the exhaust gas is made rich to an extent such that the amount of unburned HC and CO is excessive beyond an amount necessary to reduce the whole NO.sub.x.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.