Abstract: A device and method for providing a gaseous substance mixture which includes at least one reducing agent and/or at least one reducing agent precursor, includes a reservoir for an aqueous solution which includes at least one reducing agent precursor that can be flow connected to an evaporator chamber, and a device for dosing the aqueous solution in the evaporator chamber. A device can heat the evaporator chamber to a temperature higher than or equal to a critical temperature, in which the aqueous solution is at least partially evaporated. The device and method enable reducing agent to be provided for selective catalytic reduction of nitrogen oxides in the exhaust of an internal combustion engine. Preferably, an evaporator unit is configured as the evaporator chamber and a hydrolysis catalytic converter is disposed outside the exhaust system. As a result, the size of the hydrolysis catalytic converter is reduced, allowing compact construction.

Abstract: An apparatus for treating exhaust gas of an internal combustion engine, includes a feed conduit feeding aqueous solution, a hydrolysis catalytic converter connected to the feed conduit and an SCR catalytic converter through which exhaust gas flows. A rod-shaped heating element heats at least parts of the feed conduit and/or hydrolysis catalytic converter. The apparatus provides a compact structure of a feed conduit heated by a rod-shaped element and a corresponding hydrolysis catalytic converter, with which an aqueous solution containing urea can be evaporated and then hydrolyzed to a gas stream containing ammonia. This gas stream serves as a reducing agent in the SCR process. The compact configuration allows installation in very confined space conditions. The hydrolysis catalytic converter, through which exhaust gas does not flow, permits the volume of the hydrolysis catalytic converter to be decisively reduced, since significantly smaller mass flows of gas need to be hydrolyzed therein.

Abstract: A device for treating exhaust gas of an internal combustion engine includes a reducing agent solution evaporator, a hydrolysis catalytic converter connected thereto for hydrolysis of urea to form ammonia and an SCR catalytic converter for selective catalytic reduction of nitrogen oxides. The evaporator includes an evaporator unit providing a gaseous substance mixture including at least one reducing agent precursor and/or reducing agent. The evaporator unit evaporates an aqueous solution including at least one reducing agent precursor. The SCR catalytic converter is in an exhaust line, and the evaporator and the hydrolysis catalytic converter are outside of and can be connected to the exhaust line. A sufficiently large quantity of reducing agent for selective catalytic reduction of nitrogen oxides in the SCR catalytic converter can be provided, while permitting a smaller volume of the hydrolysis catalytic converter than in the prior art, since it is not traversed by exhaust gas.

Abstract: A device and a method for providing a gaseous substance mixture including at least one of a reducing agent and/or a reducing agent precursor, include a reservoir for an aqueous solution including at least one reducing agent precursor, from which the aqueous solution can be delivered into at least one metering line having a dispensing opening by a delivery device, and a device for heating the metering line above a critical temperature greater than the boiling temperature of water. Complete evaporation of an aqueous solution including urea and subsequent hydrolysis to form a substance mixture including ammonia, are carried out. The substance mixture is metered as a reducing agent into an SCR catalytic converter. Carrying out the evaporation outside the exhaust system uses considerably smaller hydrolysis catalytic converters, which is space-saving and cost-saving compared to conventional devices for providing a reducing agent for selective catalytic reduction of nitrogen oxides.