Method for operating an exhaust gas purification system of an internal combustion engine

US9765715B2 · kind B2 · utility

Assignee

• Daimler AG · DE

Inventors

• Peter Hohner · Echterdingen, DE
• Carsten Zeller · Kornwestheim, DE

Key dates

• Filing date: Oct 25, 2014
• Grant date: Sep 19, 2017
• Expiry date: Oct 25, 2034

Classification

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

Abstract

A method for operating an exhaust gas purification system of an internal combustion engine, which can be operated in a lean operating mode and in a rich operating mode, is disclosed. The exhaust gas purification system has, arranged one after the other in the direction of flow of the exhaust gas, an ammonia-forming catalyst, a first exhaust gas sensor, an ammonia-SCR catalyst, a nitrogen oxide storage catalyst and a second exhaust gas sensor. Exhaust gas sensors emit a first signal correlating with the nitrogen oxide content of the exhaust gas and a second signal correlating with the lambda value of the exhaust gas. In diagnostic operation, the ammonia storage capacity of the ammonia-SCR catalyst and the oxygen and optionally the nitrogen oxide storage capacity of the nitrogen oxide storage catalyst can be determined by analyzing the signals of the first and second exhaust gas sensors.