Exhaust gas purification system for an internal combustion engine
US5233830A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 21, 1991 |
| Grant date | Aug 10, 1993 |
| Priority date | — |
| Expiry date | May 21, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
An exhaust gas purification system for an internal combustion engine includes a dual passage portion having a first passage and a second passage which are connected in parallel to each other. In the first passage, a first catalyst constructed of lean NOx catalyst is located and further a second catalyst constructed of oxidizing catalyst or three-way catalyst is located downstream of the first catalyst. In the second passage, a third catalyst constructed of oxidizing or three-way catalyst is located. A flow switching valve is provided so as to switch the flow of exhaust gas between the first passage and the second passage. The flow switching valve is switched so that exhaust gas flows through the third catalyst when the engine is being warmed-up and flows through the first catalyst and the second catalyst after the engine has been warmed-up.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.