Process for regenerating a nitrogen oxides storage catalyst

US7351677B2 · kind B2 · utility

Assignee

• UMICORE AG & CO. KG · DE

Inventors

• Friedemann Rohr · Hanau, DE
• Peter Kattwinkel · Marienheide, DE
• Stefan Peter · Groß-Umstadt, DE
• Thomas Kreuzer · Karben, DE
• Egbert Lox · Hanau, DE

Key dates

• Filing date: Jul 29, 2003
• Grant date: Apr 1, 2008
• Expiry date: Oct 27, 2024

Classification

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

Abstract

The present invention provides a process and a device for regeneration of a nitrogen oxide storage catalyst in the exhaust system of a diesel engine. The process comprises a first and a second regeneration strategy. The first regeneration strategy is applied when the exhaust gas temperature is above a threshold value and comprises changing the air/fuel-ratio from a lean to a rich value during a first regeneration period. The second regeneration strategy is applied when the exhaust gas temperature is below a threshold value and comprises switching the air/fuel-ratio back and forth between lean and rich air/fuel-ratios, forming a sequence of between 2 and 10 rich pulses and between 2 and 10 lean pulses during a second regeneration period.