Daimler Ag

Daimler Chrysler Ag

Norbert Waldbuesser

Markus Paule

Bernd Krutzsch

Guenter Wenninger

Michel Weibel

Andreas Hertzberg

Arno Nolte

Stefan Renfftlen

Rolf Wunsch

Brigitte Bandl-Konrad

Rainer Hegemann

Eugen Neuberger

A method for operating an exhaust gas purification system of a motor vehicle internal combustion engine is disclosed. The system has an SCR catalyst where a reducing agent containing ammonia is metered into the exhaust gas at a predeterminable metering rate which is produced from a base value and an adaptation factor which corrects the base value. A test procedure checks and, if appropriate, adjusts the adaptation factor where a first nitrogen oxide value is compared with a second nitrogen oxide value of the exhaust gas, where the first and the second nitrogen oxide value are determined by the same nitrogen oxide sensor disposed downstream of the SCR catalyst. The first nitrogen oxide value is determined when the metering of the reducing agent is switched off and the second nitrogen oxide value is determined when the reducing agent is metered at a test metering rate which can be predetermined.

Method for operating an exhaust gas purification system of a motor vehicle combustion engine

An exhaust gas aftertreatment installment and associated exhaust gas aftertreatment method utilizes a nitrogen oxide storage catalytic converter and an SCR catalytic converter. A particulate filter is provided upstream of the nitrogen oxide storage catalytic converter or between the latter and the SCR catalytic converter or downstream of the SCR catalytic converter. The time of regeneration operating phases of the nitrogen oxide storage catalytic converter can be determined as a function of the nitrogen oxide content of the exhaust gas downstream of the nitrogen oxide storage catalytic converter or of the SCR catalytic converter and/or as a function of the ammonia loading of the latter. Moreover, a desired ammonia generation quantity can be determined for a respective regeneration operating phase. The installation and method are adopted for use for motor vehicle internal combustion engines and other engines which are operated predominantly in lean-burn mode.

Exhaust gas aftertreatment installation and method

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Stuttgart, Germany

Norbert Waldbuesser