Process for operating an exhaust gas treatment device for a gasoline engine

US6601381B2 · kind B2 · utility

Assignee

• DMC2 Degussa Metal Catalysts Cerdec AG · DE

Inventors

• Lothar Mussmann · Offenbach, DE
• Dieter Lindner · Hanau, DE
• Martin Votsmeier · Bruchköbel, DE
• Joerg-Michael Richter · Scheinfeld, DE
• Egbert Lox · Hanau, DE

Key dates

• Filing date: May 16, 2001
• Grant date: Aug 5, 2003
• Expiry date: May 16, 2021

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/40
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

A process for operating an exhaust gas treatment device in a gasoline engine which is operated mainly with a stoichiometric air/fuel ratio and is operated with a rich-mix air/fuel ratio when accelerating or under full load. The exhaust gas treatment device contains a three-way converter catalyst and a first lambda probe upstream of the catalyst and a second lambda probe downstream of the catalyst. The air/fuel ratio is controlled by using the signal from the first lambda probe, whereas the signal from the second lambda probe is used to check the first lambda probe (trim control) and to diagnose the function of the catalyst. Trim control with the second lambda probe is enabled only when, in the event of rich exhaust gas, the voltage difference between the probe voltage for the second lambda probe and a set point voltage is not larger than a predetermined value.