Method for removing nitrogen oxides and particulates from the lean exhaust gas of an internal combustion engine and exhaust gas emission system

US6938411B2 · kind B2 · utility

Assignee

• UMICORE AG & CO. KG · DE

Inventors

• Michael Hoffmann · Gablingen, DE
• Harald Klein · Bessenbach, DE
• Thomas Kreuzer · Karben, DE
• Adolf Schafer-Sindlinger · Frankfurt, DE

Key dates

• Filing date: May 8, 2001
• Grant date: Sep 6, 2005
• Expiry date: May 8, 2021

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/40
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

A method for removing nitrogen oxides and particulate matter from the lean exhaust gas of a combustion engine that also contains low concentrations of sulfur oxides. The exhaust gas stream is passed over a nitrogen oxide storage catalyst and a particulate filter, where nitrogen oxides and sulfur oxides are adsorbed by the storage catalyst under lean exhaust gas conditions and the particulate matter is deposited on the particulate filter. The storage catalyst is in a first cycle is periodically denitrated by enriching the exhaust gas regeneration of the particulate filter. Desulfurization of the nitrogen oxide storage catalyst is carried out in a second cycle by raising the temperature of the lean exhaust gas to a value at which the particulate matter combustion on the particulate filter is initiated and then the storage catalyst can be desulfurized by enriching the exhaust gas.