Method for determining the nitrogen dioxide concentration in exhaust gases

US8191413B2 · kind B2 · utility

Assignee

• Daimler AG · DE

Inventors

• Jochen Lahr · Stuttgart, DE
• Rainer Pauls · Leinfelden, DE

Key dates

• Filing date: Dec 20, 2008
• Grant date: Jun 5, 2012
• Expiry date: Apr 7, 2029

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02A50/20
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

In a method for determining an NO2 concentration and/or a concentration ratio of NO2 and NO in an exhaust tract of a combustion device, such as an internal combustion engine, an NOx sensor that is sensitive with respect to NO2 and NO is utilized, which provides a NOx output signal correlating with an NOx concentration representing the sum of the concentrations of NO2 and NO. In order to determine the NO2 concentration and/or the concentration ratio of NO2 and NO, the NOx output signal of a first NOx sensor, which is arranged upstream of an exhaust gas treatment element arranged in the exhaust tract and having the capability of converting NO to NO2 and/or converting NO2 to NO, is compared to the NOx output signal of a second NOx sensor, which is disposed downstream of the exhaust gas treatment element.