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AssigneeSiemens Aktiengesellschaft
InventorsGerhard Wissler, Günther Pajonk, Manfred Weigl, Lothar Hofmann
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When determining the amount of a reducing agent solution to be introduced into the exhaust gas of a combustion system, in particular of a diesel engine, for catalytically reducing the nitrogen oxides by the SCR process, the concentration of the reducing agent in the reducing agent solution as well as the parameters characterizing the operating state of the combustion system, the exhaust gas and/or the catalyst are taken into consideration. As a result, the safety margin with respect to a theoretically optimum amount to be introduced that is required to avoid a leakage of reducing agent can be reduced, whereby the conversion rate of the nitrogen oxides is improved.
A method for catalytically reducing nitrogen oxides in an exhaust gas of a combustion system by reaction of the nitrogen oxides with a reducing agent in a presence of a catalyst, which comprises the following steps:
A method for catalytically reducing nitrogen oxides in the exhaust gas of a combustion system by reaction of said nitrogen oxides with a reducing agent in the presence of a catalyst, comprising the steps of
A device for catalytically reducing nitrogen oxides in the exhaust gas of a combustion system, comprising an exhaust line, a source of reducing agent, a catalyst, a metering device disposed upstream of the catalyst in the direction of flow of the exhaust gas for introducing a defined amount of reducing agent into the exhaust gas, a monitoring unit connected to said metering device for determining the amount of reducing agent solution to be metered from at least one parameter characterizing the operating state of the combustion system, the exhaust gas, and/or the catalyst, and a sensor in communication with said monitoring unit for measuring the concentration of the reducing agent solution, wherein said source is a solution of reducing agent in a storage container and the concentration of the reducing agent in said source is determined discontinuously each time said container is filled with the reducing agent solution such that the monitoring unit adapts the amount of reducing agent solution to be metered to said concentration available trough the sensor.
Dependencies are inferred from the claim text.