Exhaust emission control device for internal combustion engine
US6679050B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 16, 2000 |
| Grant date | Jan 20, 2004 |
| Priority date | — |
| Expiry date | Mar 16, 2020 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
The exhaust pipe (7) of an engine (1) is provided with a front three-way catalyst (8) and a rear three-way catalyst (9). A controller (6) determines whether temperature rise conditions in the rear three-way catalyst (9) are satisfied. When temperature rise conditions in the rear three-way catalyst (9) are satisfied, the air-fuel ratio of the exhaust gas flowing into the front three-way catalyst (8) is made to fluctuate periodically to rich or lean about the stoichiometric air-fuel ratio, and the amplitude of air-fuel ratio fluctuation is increased. In this way, temperature rise of the front three-way catalyst (8) is suppressed, and the temperature of the rear three-way catalyst (9) rises.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.