Device for purifying exhaust gas of engine
US6058700A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 22, 1998 |
| Grant date | May 9, 2000 |
| Priority date | — |
| Expiry date | May 22, 2018 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D2200/0806
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A device for purifying the exhaust gas of an engine comprises a NO.sub.X absorbent arranged in the exhaust passage. The NO.sub.X absorbent absorbs NO.sub.X therein when the air-fuel ratio of the inflowing exhaust gas is lean, and releases the absorbed NO.sub.X therefrom when the oxygen concentration in the inflowing exhaust gas becomes lower. The NO.sub.X absorbent also absorbs SO.sub.X therein when the air-fuel ratio of the inflowing exhaust gas is lean, and releases the absorbed SO.sub.X therefrom when the oxygen concentration in the inflowing exhaust gas becomes lower, with the temperature of the NO.sub.X absorbent being higher than a SO.sub.X releasing temperature. The air-fuel ratio of the exhaust gas flowing to the NO.sub.X absorbent is made rich temporarily when the temperature of the NO.sub.X absorbent is higher than SO.sub.X releasing temperature and when the flow rate of the exhaust gas flowing through the NO.sub.X absorbent is lower than a predetermined flow rate, to release the absorbed SO.sub.X from the NO.sub.X absorbent.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.