Exhaust gas system for exhaust gas after-treatment

Abstract

The invention relates to an exhaust gas system (1) in a motor vehicle, comprising: a dosing module (4) for feeding a fluid, in particular a fluid reducing agent, into the exhaust gas system (1); and at least two mixing elements (3), which are designed to mix the exhaust gas flowing through the exhaust gas system (1) with the fed fluid, wherein the dosing module (4) is designed to feed a part of the fluid into the exhaust gas system (1) substantially opposite the gas flow direction (10) and to feed another part of the fluid into the exhaust gas system (1) substantially in the gas flow direction(10), at least one mixing element (3) is arranged upstream of the dosing module (4) in the exhaust gas system (1) and at least one mixing element (3) is arranged downstream of the dosing module (4) in the exhaust gas system (1).

Description

technical field [0001] The invention relates to an exhaust gas system in a motor vehicle having at least one metering module for feeding or injecting a fluid, in particular a fluid reducing agent, into the exhaust system; and having at least two mixing elements , the mixing element is designed to mix at least one gas flowing through the exhaust gas system, in particular exhaust gas, with the fed-in fluid. The fluid is, for example, a fluid reducing agent, especially a urea solution. Background technique [0002] In order to keep the air pollution caused by the emitted exhaust gases as low as possible, aftertreatment of the exhaust gases is necessary. For such exhaust gas aftertreatment of internal combustion engines, especially diesel engines, in particular so-called SCR systems (SCR = "Selective Catalytic Reduction"), with which the nitrogen oxides contained in the exhaust gas are reduced ( NOx). [0003] In order to reduce nitrogen oxides in the exhaust gas, a reducing ...

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Problems solved by technology

[0004] However, it has been shown that there is a risk that a part of the reducing agent injected or fed into the exhaust system does not evaporate completely and, for example, sticks to the mixing elements and / or the boundaries of the exhaust system and forms deposits which can negatively influence the reduction of harmful substances , so that this deposit e.g. increases fuel consumption and / or increases emissions of harmful substances and even leads to clogging of the exhaust system

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