Daimler Ag

Daimler Chrysler Ag

Dirk Herbstritt

Michael-Rainer Busch

Carsten Plog

Aleksandar Knezevic

Ralf Müller

Uwe Hofmann

Andreas Miksch

Markus Amman

Nikolas Fekete

In an operating and diagnostic method for an SCR exhaust gas aftertreatment system which has an SCR catalytic converter with ammonia storage capacity, a signal of an exhaust gas sensor that is sensitive to nitrogen oxide and ammonia and is arranged downstream of the SCR catalytic converter, is measured. In a normal operating mode, ammonia is supplied to the SCR catalytic converter corresponding to a filling level model for ammonia stored in the SCR catalytic converter, in such a way that the ammonia filling level of the SCR catalytic converter is held at least approximately at a predefinable nominal value (or value range). The normal operating mode is interrupted if an exhaust gas sensor signal that exceeds a predefinable first limit value, is registered, and the set urea dosing rate is increased by a predefinable degree in relation to the value provided in the normal operating mode. Thereafter, a return is made to the normal operating mode, or a switch is made to a diagnostic operating mode, as a function of the profile of the signal of the exhaust gas sensor.

Operating and diagnostic method for an SCR exhaust-gas aftertreatment system

A method and apparatus for detecting the presence of a prescribed heat exchanger, such as a catalytically active radiator, in a motor vehicle are performed during operation of the motor vehicle. The temperature of a heat-exchanger medium is observed together with further current operationally relevant parameters of the motor vehicle for a prespecified time window. An expected temperature gradient over time of the heat-exchanger medium is detected, as well as the current temperature gradient over time of the temperature of the heat-exchanger medium. The presence of a prescribed heat exchanger is detected taking into account the expected temperature gradient and the current temperature gradient.

Method and apparatus for detecting the presence of a prescribed heat exchanger

In a device for determining an exhaust gas recirculation rate (EGR) in an internal combustion engine, wherein the device includes a sensor unit, which in a first region is exposed to an exhaust-gas atmosphere from an exhaust gas recirculation line and in a second region is exposed to an exhaust gas/fresh air atmosphere in an intake line of the internal combustion engine downstream of a location where the exhaust gas recirculation line opens into the intake line, the sensor unit disposed in the intake line is tubular with the inner side of the sensor unit being exposed to the exhaust gas atmosphere and the outer side of the sensor unit being exposed to the exhaust gas/fresh air atmosphere. The sensor unit is preferably positioned centrally within the intake line away from the wall of the intake line.

Device for determining the exhaust gas recirculation rate of an internal combustion engine

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Durmersheim, Germany

Dirk Herbstritt