Method for operating a nitrogen oxide storage catalyst in a diesel engine

US7670577B2 · kind B2 · utility

Assignee

• UMICORE AG & CO. KG · DE

Inventors

• Friedemann Rohr · Hanau, DE
• Lutz Marc Ruwisch · Darmstadt, DE
• Markus Koegel · Brohl, DE
• Juliane Kluge · Munich, DE
• Ulrich Goebel · Hattersheim, DE

Key dates

• Filing date: Oct 19, 2006
• Grant date: Mar 2, 2010
• Expiry date: Nov 5, 2026

Classification

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

Abstract

A nitrogen oxide storage catalytic converter which is operated for a relatively long time at low exhaust-gas temperatures in the range between 120 and 250° C. exhibits a decreasing storage capacity as a result of incomplete regeneration at said temperatures. In order to re-establish the original storage capacity of the catalytic converter which is operated in this way, two-stage regeneration is proposed, wherein the storage catalytic converter is initially partially regenerated at the low exhaust gas temperature by means of a switch from the lean mode to the rich mode, and wherein subsequently, with rich exhaust gas again, the exhaust-gas temperature of the engine is raised into a range of between 300 and 400° C. for complete regeneration.