Exhaust gas purifying device for engine
US5884476A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 8, 1997 |
| Grant date | Mar 23, 1999 |
| Priority date | — |
| Expiry date | Sep 8, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/40
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
An exhaust gas purifying device, for an engine performing a lean operation and having an EGR system capable of controlling an EGR ratio, comprises a NO.sub.X catalyst arranged in the exhaust passage capable of selectively reducing NO.sub.X in the inflowing exhaust gas, in the oxidizing atmosphere including a reducing agent, and a reducing agent injector arranged in the exhaust passage of the engine for secondarily supplying a reducing agent to the exhaust passage upstream of the NO.sub.X catalyst. The EGR system has an EGR passage connecting the exhaust passage and the intake passage of the engine, an EGR control valve arranged in the EGR passage, and an intake air control valve arranged in the intake passage upstream of an inlet of the EGR passage. The openings of the EGR control valve and the intake air control valve are controlled to control the temperature of the exhaust gas to make the temperature of the NO.sub.X catalyst within the optimum temperature range or equal to the optimum temperature. The amount of the reducing agent injected by the reducing agent injector is made smaller as the EGR ratio becomes higher.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.