Dual catalyst NOx reduction system for exhaust from lean burn internal combustion engines
US8245500B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 7, 2008 |
| Grant date | Aug 21, 2012 |
| Priority date | — |
| Expiry date | Mar 16, 2031 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A method and apparatus for reducing the percentage of nitrogen dioxide and nitrogen monoxide in an exhaust gas stream of an internal combustion engine, comprising the steps of injecting a hydrocarbon compound and optionally hydrogen into the exhaust gas stream; passing the exhaust gas through a first catalyst for selective reduction of a portion of the nitrogen oxides to nitrogen, ammonia, and N-containing species; passing the exhaust gas through a second catalyst for selective reduction of a portion of the nitrogen oxides with ammonia to molecular nitrogen; sensing ammonia concentration in the exhaust gas stream after passage through either or both of the first and second catalysts; and controlling by a controller in a feedback loop the injecting to an amount of hydrocarbon that will produce a predetermined concentration of ammonia and nitrogen oxides at the sensor that will lead to high NOx conversion.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.