Reduction of NO.sub.x in the exhaust gases from internal combustion engines containing excess oxygen
US6087295A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 30, 1998 |
| Grant date | Jul 11, 2000 |
| Priority date | — |
| Expiry date | Jun 30, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Removal of carbon monoxide, hydrocarbons, and nitrogen oxides from the exhaust gas from lean-burn, diesel and other engines which produce exhaust gases containing excess oxygen is provided by a multi-component catalyst having at least two catalytic components, each capable of reducing nitrogen oxides within a range of exhaust gas temperatures that is different from the range of exhaust gas temperatures within which each other component is capable of reducing nitrogen oxides. Oxidation of the remaining reducing gases is also accomplished. One example of a two catalytic component catalyst of this invention has a first component of Au supported on alumina, which reduces nitrogen oxides at exhaust gas temperatures between about 600.degree. C. and 900.degree. C., and a second component of Pt supported on Y-zeolite, which reduces nitrogen oxides at exhaust gas temperatures below 600.degree. C.; an example of a three catalytic component catalyst of this invention has a first component of CoO supported on .gamma.-alumina, which reduces nitrogen oxides at exhaust gas temperatures above about 475.degree. C., a second component of an alloy of Pt, Rh and Co supported on BaO.sub.2 -stabilized .…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.