Abstract: In a metering apparatus for the metered introduction of a first medium into an exhaust gas system of an internal combustion engine, which includes a conditioning apparatus in which also a second medium is introduced via a dispensing apparatus which is connected to the conditioning apparatus and via which the first medium and the second medium are introduced into the exhaust gas system, a supply unit for supplying a third medium, which is different from the second medium in its physical properties and/or its chemical composition, is connected to the conditioning apparatus for cleaning of the conditioning apparatus and the dispensing apparatus from constituent parts of the first medium by the third medium or a mixture of the second and the third medium.

Abstract: A method for determining the storage state of an ammonia-storing SCR catalyst, the change in at least one physical property of the SCR catalyst material, changing with the NH3 storing process, being sensed, the measurement taking place on the SCR catalyst material itself by applying a measuring pickup to the SCR catalyst or bringing it into direct contact with the latter and determining the storage state on the basis of these results.

Abstract: A supercharged internal combustion engine has an exhaust gas turbocharger which includes an exhaust gas turbine and a compressor. The exhaust gas turbine and the compressor are connected to a turbocharger shaft and an appliance for the transmission of power for the purpose of a mechanical step-up drive capability for the exhaust gas turbocharger arranged between the turbocharger shaft and the crankshaft of the internal combustion engine. The appliance includes at least one step-up gear and a controllable hydrodynamic coupling for torque transmission arranged between the crankshaft and the turbocharger shaft.

Abstract: An exhaust gas aftertreatment device for internal combustion engines having a catalyzer for the selective catalytic reduction of oxides of nitrogen from exhaust gases of motor vehicle diesel engines, provides overstoichiometric supply of NH.sub.3 or materials releasing NH.sub.3. A first sensor records the NH.sub.3 concentration contained in the exhaust gas and interrupts the supply of the NH.sub.3 quantity when a specified upper threshold value is reached. A second sensor records the NH.sub.3 adsorbed in the catalyzer, by way of which the NH.sub.3 supply is resumed on reaching a specified lower threshold value. Alternatively, only one NH.sub.3 sensor is provided in the exhaust gas aftertreatment device. The NH.sub.3 concentration determined by this single sensor is compared, as the actual value, with a required value corresponding to a specified NH.sub.3 concentration in order to form a correction signal which is used for triggering the metering appliance continuously connected into the gas phase.