Exhaust-gas cleaning system and method with internal ammonia generation, for the reduction of nitrogen oxides

US6662552B1 · kind B1 · utility

Assignee

• Daimlerchrysler AG · US

Inventors

• Josef Gunther · Marbach am Neckar, DE
• Bernd Krutzsch · Köngen, DE
• Christof Schoen · Winnenden, DE
• Dirk Voigtlaender · Ditzingen, DE
• Miechel Weibel · Stuttgart, DE
• Marko Weirich · Mannheim, DE

Key dates

• Filing date: Dec 3, 2001
• Grant date: Dec 16, 2003
• Expiry date: Dec 3, 2021

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/12
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

An exhaust-gas cleaning system removes at least nitrogen oxides contained in exhaust-gas from a combustion source. An ammonia-generation catalytic converter generates ammonia using constituents of at least some of the exhaust gas emitted from the combustion source during ammonia-generation operating phases. Downstream a nitrogen oxide reduction catalytic converter reduces nitrogen oxides which are contained in the exhaust gas emitted from the combustion source using the ammonia generated as reducing agent. A nitrogen monoxide generation unit is situated outside the combustion source, for enriching the exhaust gas which is fed to the ammonia-generation catalytic converter with generated nitrogen monoxide during the ammonia-generation operating phases. The system is used for cleaning exhaust gases of motor vehicle internal-combustion engines which are operated predominantly in lean-burn mode, removing nitrogen oxides which are contained therein.