Method of reducing NO.sub.x emissions from lean-burn combustion engines
US5609022A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 31, 1994 |
| Grant date | Mar 11, 1997 |
| Priority date | — |
| Expiry date | Oct 31, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
The invention includes an operating strategy for zeolite-based catalysts used for reduction of NO.sub.x from highly lean exhaust conditions. The invention includes a method to enhance the high temperature activity of zeolite-based catalysts by modifying the transient feed composition without changing the overall time-average feed composition. More specifically, a cyclic operation method with alternating feed conditions between rich and lean to enhance the activity of zeolite-based catalysts to remove NO from lean exhaust gases when the overall exhaust composition contains a large amount of excess oxygen, without affecting the catalyst's activity to remove hydrocarbons. The rich to lean transient conditions are created by periodically adding hydrocarbon pulses from a different source to the combustion emissions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.