摘要:
A device for exhaust gas treatment includes an exhaust gas line through which an exhaust gas can flow in a flow direction, a supply for feeding a reducing agent into the exhaust gas line, a regulating unit for dosing the reducing agent to be supplied, and a carrier body for bringing about a chemical reaction of the reducing agent with at least one constituent of the exhaust gas. The carrier body is positioned downstream of the supply in the flow direction, and the carrier body has at least one metallic base body at least partially including a coating with a storage capability for the reducing agent. Two methods for the dosed provision of a reducing agent, especially a solid reducing agent, are also provided. The methods and device allow economical use of the reducing agent while guaranteeing an approximately 100% reaction of the nitrogen oxides contained in the exhaust gas.
摘要:
A device for treating exhaust gases includes a particle separator, an SCR catalytic converter for selectively reducing nitrogen oxides and an ammonia generator for generating ammonia as a selective reducing agent for reducing nitrogen oxides. The particle separator is provided in a main exhaust line and the ammonia generator is provided in a first secondary line. The first secondary line opens into the main exhaust line at a junction in such a way that an ammonia-containing gas stream generated in the ammonia generator can flow through the SCR catalytic converter. The method and the device advantageously permit the proportion of particles and nitrogen oxides (NOx) contained in the exhaust gas of an internal combustion engine to be reduced simultaneously, with the energy consumption for this reduction being small and at the same time the entire device being embodied as a compact unit.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
A method positions a sensor in a honeycomb body which is provided with hollow spaces that can be penetrated at least in part by an exhaust gas. The sensor is placed in an area of the honeycomb body in which at least one minimum hydrogen concentration occurs when the honeycomb body is operated in the emission system of a motor vehicle. The sensor positioning method allows the sensor to be placed in the honeycomb body in such a way that systematic errors that occur are kept as small as possible as a result of an inherent transverse sensitivity of the sensor to hydrogen. This applies especially to lambda probes. A honeycomb body contains the sensor which is placed so as to supply particularly reliable test data whose systematic error is as small as possible.
摘要:
A process for producing a body for exhaust gas treatment having a plurality of metallic layers, includes bringing the layers into contact with each other in a connection region. A connection is made by a roller seam welding process in such a way that the layers form passages through which a gas stream can flow. A corresponding body for exhaust gas treatment can especially be used as a filter or catalyst carrier body in the automobile industry.
摘要:
A carrier body includes an overall surface having at least one coating portion with a catalytically active coating including at least one type of catalyst elements disposed in dispersed form at a surface of the carrier body. The catalyst elements have a mean spacing along the surface of at least 3 micrometers. The surface has a mean roughness depth Rz of 2 to 10 micrometers. The carrier body has a maximum increase in pressure loss compared to a carrier body with a smooth and uncoated surface of 25%. A process for producing a carrier body and an exhaust gas treatment unit and a vehicle having a carrier body, are also provided.
摘要:
A method for removing particulates from a gas stream includes providing a gas-permeable filter layer having subregions with a parameter of differing magnitudes in the direction of the layer thickness. This parameter relates at least to the porosity, the fiber diameter of fibers or the fiber type content of the filter layer. The gas stream is divided into partial gas streams which are each passed through different subregions of the filter layer. Fiber layers, particulate filters, exhaust systems and vehicles based on this method are also provided.