Removing nitrogen oxides during a lean-burn engine cold start
US6938412B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 7, 2003 |
| Grant date | Sep 6, 2005 |
| Priority date | — |
| Expiry date | Aug 7, 2023 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
An apparatus and a method for removing NOx from an exhaust stream of a lean-burn engine during an engine cold start are provided. The apparatus includes a close-coupled LNT coupled to a main LNT by a hollow conduit. NOx from the cold exhaust is initially stored on the close-coupled LNT. As the engine exhaust warms up, the close-coupled LNT reaches its operating temperature and reduces the stored NOx to N2. When the temperature of the close-coupled LNT reaches approximately 350° C., NOx is released from the close-coupled LNT, is absorbed on the main LNT, and is converted to N2 during fuel-rich conditions, The close-coupled LNT can be regenerated after the engine is turned off by providing heat. The released NOx during the regeneration of the closed-coupled LNT is absorbed by the main LNT. The stored NOx on the main LNT can be reduced to N2 during the next vehicle operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.