Ammonia injection in NOx control
US5992141A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 19, 1997 |
| Grant date | Nov 30, 1999 |
| Priority date | — |
| Expiry date | Mar 19, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Improvements are described in the injection of ammonia (NH.sub.3) into the exhaust gases of an engine to reduce nitrogen oxides. Instead of merely injecting ammonia into the exhaust gas conduit through a hole in its side, an ammonia injector (90) is provided that projects considerably into the exhaust conduit (16), with the injector having a plurality of holes (94). The ammonia is activated to decompose it into its reactive components, including NH.sub.2 and NH prior to injecting it into the exhaust conduit. Such activation prior to injection can be accomplished by heating the ammonia in the presence of a catalyst such as a metal of the platinum group, iron, nickel, or zinc. In an engine that has a fuel injection system wherein electrical pulses are delivered to fuel injectors to control the fuel flow rate, the durations of these electrical signals are used to control the opening of a valve (72) that controls the flow rate of ammonia into the exhaust gas conduit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.