Robert Boschgmbh

Ralf Wegst

Peter Riegger

Thorsten Raatz

Norbert Breuer

Andreas Genssle

Franz Josef Trompeter

Frank Ilgner

Stefan Woerz

Markus Hernier

Markus Gloeckle

Thomas Hauber

Franz-Josef Trompeter

The invention concerns a procedure to heat a reducing agent generation system of an exhaust gas aftertreatment system of an internal combustion engine by combustion of fuel, whereby the reducing agent is produced for the selective catalytic reduction of nitrogen oxides in the exhaust gas of the internal combustion engine in the intermittently operated reducing agent generation system, whereby the reducing agent generation system consists of a plasma burner, a mixing chamber located downstream or upstream from the plasma chamber, an oxidation reformation unit as well as a nitrogen oxide storage/ammonia production unit and whereby nitrogen oxide is produced in a plasma in the plasma burner. The invention concerns additionally a corresponding device. The task of the invention concerning the procedure is thereby solved, in that the combustion of the fuel is ignited by the plasma. For this reason, the heating of the catalytic components required at the start of the reducing agent generation system results through the combustion of fuel by means of a burner functionality, which consists of a fuel metering mechanism and the existing plasma burner. A special heating burner as an auxiliary mechanism can be omitted.

Procedure and device to heat a reducing agent generation system

Devices and methods for the production of ammonia as a reducing agent for the selective catalytic reduction (SCR) of nitrogen oxides in the exhaust gas of a combustion source, especially of an internal combustion engine. The ammonia is admixed with the exhaust gas in the direction of flow in front of a SCR-catalytic converter. In so doing, nitrogen oxide is produced in a nitrogen oxide production unit separated from the combustion source and its exhaust gas duct and is stored in at least one storage catalytic converter or a nitrogen oxide storage and a subsequently connected catalytic converter. Furthermore, hydrogen and/or a hydrogen-carbon monoxide-mixture is produced in a hydrogen production unit separated from the combustion source and its exhaust gas duct and delivered to a storage catalytic converter. Hydrogen and the stored nitrogen oxide are converted catalytically to ammonia in the storage catalytic converter or in the catalytic converter.

Device and procedure for the production of ammonia

The invention relates to a procedure for controlling the reducing agent in an exhaust gas post-processing system of a combustion machine with an exhaust gas duct, in which an SCR catalytic converter is provided in the direction of flow of the exhaust, wherein a reducing agent generation system has an NOand CO/Hgeneration unit,, an oxidation catalytic converter and a combined NOstorage / ammonia generation unit in the standard gas route of the reducing agent generation system, and, in order to reduce nitrogen oxide, ammonia is added as a reducing agent in front of the SCR catalytic converter by the reducing agent generation system, wherein source materials for the generation of ammonia are at least intermittently added to the NOand CO/Hgeneration unit via a fuel supply line and via an air supply line, wherein during the fat phase the air/fuel composition is changed in front of the oxidation catalytic converter in the form of a lambda modulation for a lambda value. It can thus be achieved that, in pulse mode, a high H/CO yield can be achieved with a simultaneously low HC slip and the higher HC penetrations associated with the natural aging of the catalytic converter and the decreasing H/CO yields are compensated. Influences resulting from the reactor geometry of the oxidation catalytic converter can be influences or compensated with the procedure in terms of its drive-away characteristic.

Procedure for controlling the reducing agent in an exhaust gas post-processing system

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Gaggenau, Germany

Ralf Wegst