Daimler Ag

Alexander Kaiser

Markus Paule

Bernd Christner

Berthold Keppeler

Holger Kissling

Uwe Hofmann

In a system with an SCR catalytic converter, a correction by a changeable long term adaption factor to a target dosing rate is provided for the model dosing rate and a correction by a changeable short term adaption factor to an assumed actual filling state for the ammonia filling level value. A dosing unit controllable by a control unit adds an ammonia-containing reducing agent to the exhaust gas and an exhaust gas enriched with ammonia according to the dosing is fed to the SCR catalytic converter. An ammonia filling level value for a filling level of ammonia stored in the SCR catalytic converter and a model dosing rate for dosing the reducing agent into the exhaust gas are calculated by a computer model.

Method for operating an exhaust gas treatment system having an SCR catalytic converter

In a method for operating an air-compressing fuel-injection internal combustion engine having an exhaust gas post-treatment system with a particle filter and a nitrogen oxide reduction catalytic converter, a plurality of internal combustion engine operating settings are provided, each having respective predefined values for predefined internal combustion engine operating parameters. A heating operating setting is set when the internal combustion engine is warming up, while a basic operating setting is set in the warmed-up state. When the temperature in the exhaust gas system exceeds a predefinable first value, the heating operating setting is changed over to the basic operating setting. In the warmed-up state, at least one further (third) operating setting, with an exhaust gas recirculation rate that is reduced compared to the basic operating setting, is provided in addition to the basic operating setting.

Method for operating an internal combustion engine

In a method for operating an air-compressing fuel-injection internal combustion engine having an exhaust gas post-treatment system with a particle filter and a nitrogen oxide reduction catalytic converter, a plurality of internal combustion engine operating settings are provided, each having respective predefined values for predefined internal combustion engine operating parameters. A heating operating setting is set when the internal combustion engine is warming up, while a basic operating setting is set in the warmed-up state. When the temperature in the exhaust gas system exceeds a predefinable first value, the heating operating setting is changed over to the basic operating setting. In the warmed-up state, at least one further, (third) operating setting, with an exhaust gas recirculation rate that is reduced compared to the basic operating setting, is provided in addition to the basic operating setting.

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Fellbach, Germany

Alexander Kaiser