Exhaust Gas System of an Internal Combustion Engine

Abstract

An exhaust gas system of an internal combustion engine comprises a pipe section which is disposed in the exhaust train of the exhaust gas system and to which a main fluid containing an exhaust gas is supplied, in particular at an angle to the flow axis of the pipe section. The exhaust gas system comprises a device for injecting a further fluid, in particular a water-urea mixture or a liquid fuel, into the pipe section. Means, in particular stationary means, for generating a swirl by which the spray cone of the injected further fluid is preferably set up are provided in the inlet region of the pipe section.

1 . An exhaust gas system of an internal combustion engine having a pipe section with a flow axis, the pipe section being disposed in the exhaust train of the exhaust gas system and a main fluid containing an exhaust gas is able to be supplied to the pipe section,
 wherein the exhaust gas system comprises a device for injecting a further fluid into the pipe section; and wherein means are provided in the inlet region of the pipe section for generating a swirl.   
     
     
         2 . The exhaust gas system in accordance with  claim 1 , wherein the pipe section comprises an outer pipe and in inner pipe, and wherein means for generating a swirl are provided in an inlet region of the outer pipe and/or in an inlet region of the inner pipe. 
     
     
         3 . The exhaust gas system in accordance with  claim 2 , wherein the swirl-generating means are arranged and designed such that as little core flow as possible arises within the pipe section or within the inner pipe and such that a spray cone of the injected further fluid is radially set up. 
     
     
         4 . The exhaust gas system in accordance with  claim 2 , wherein the injection device comprising at least one nozzle is arranged and designed such that the further fluid is injected axially centrally into the pipe section or into the inner pipe of the pipe section; and/or wherein the further fluid penetrates homogenously into an inlet plane of the pipe section or of the inner pipe of the pipe section. 
     
     
         5 . The exhaust gas system in accordance with  claim 2 , wherein the swirl-generating means comprise a plurality of stationary, swirl-generating guide vanes which are distributed over an inner periphery of the pipe section or over an inner periphery of the outer pipe or inner pipe of the pipe section and which generally each extend radially inwardly starting from the inner wall of the pipe section or from the inner wall of the outer pipe or inner pipe of the pipe section. 
     
     
         6 . The exhaust gas system in accordance with  claim 5 , wherein the radial penetration depth of the swirl-generating guide vanes is respectively larger than 10% of the inner diameter of the pipe section or of the outer pipe or inner pipe of the pipe section. 
     
     
         7 . The exhaust gas system in accordance with  claim 5 , wherein the swirl-generating guide vanes are at least partly generated by incisions in the jacket of the pipe section or in the jacket of the outer pipe or inner pipe of the pipe section and the swirl-generating guide vanes integral with the respective jacket are bent inwardly. 
     
     
         8 . The exhaust gas system in accordance with  claim 5 , wherein the swirl-generating guide vanes extend, starting from an inlet-side margin of the pipe section or starting from an inlet-side margin of the outer pipe or inner pipe of the pipe section, inwardly in a direction of the flow axis of the pipe section. 
     
     
         9 . The exhaust gas system in accordance with  claim 5 , wherein the swirl-generating guide vanes are bent inwardly in accordance with an angle less than or equal to 90° with respect to the inner periphery of the pipe section or with respect to the inner periphery of the outer pipe or inner pipe of the pipe section. 
     
     
         10 . The exhaust gas system in accordance with  claim 5 , wherein the swirl-generating guide vanes or incisions introduced into the jacket of the pipe section or into the jacket of the outer pipe or inner pipe of the pipe section have a height measured in the direction of the flow axis of the pipe section in the range from 10% to 75% of the inner diameter of the pipe section or of the inner diameter of the outer pipe of the pipe section. 
     
     
         11 . The exhaust gas system in accordance with  claim 2 , wherein the ratio between a cross-sectional area of an annular clearance formed between the outer pipe and the inner pipe of the pipe section to an inner cross-section of the outer pipe of the pipe section is less than or equal to 9:16; and/or wherein the pipe section is designed and is integrated into the exhaust train such that a mass flow through the annular clearance formed between the outer pipe and the inner pipe of the pipe section is less than 25% of the mass flow through the inner pipe of the pipe section. 
     
     
         12 . The exhaust gas system in accordance with  claim 2 , wherein the outer pipe and the inner pipe of the pipe section have an equal or a different length measured in the direction of the flow axis of the pipe section. 
     
     
         13 . The exhaust gas system in accordance with  claim 2 , wherein inlet openings and/or outlet openings of the outer pipe and of the inner pipe of the pipe section lie in the same plane. 
     
     
         14 . The exhaust gas system in accordance with  claim 2 , wherein inlet openings and/or outlet openings of the outer pipe and of the inner pipe of the pipe section lie in different planes. 
     
     
         15 . The exhaust gas system in accordance with  claim 2 , wherein the inlet region of the inner pipe of the pipe section lies within or outside the outer pipe of the pipe section; and/or wherein the outlet region of the inner pipe of the pipe section lies within or outside the outer pipe of the pipe section. 
     
     
         16 . The exhaust gas system in accordance with  claim 1 , wherein the pipe section is arranged between two further components of the exhaust gas system. 
     
     
         17 . The exhaust gas system in accordance with  claim 1 , wherein a plurality of mixers are connected in series as further swirl and evaporator elements in the pipe section. 
     
     
         18 . The exhaust gas system in accordance with  claim 17 , wherein the mixers are provided with cross-sectional openings which are designed such that a predefinable critical spray application per surface is not exceeded. 
     
     
         19 . The exhaust gas system in accordance with  claim 11 , wherein the inner pipe of the pipe section is provided with passage openings via which the mass flow through the annular clearance formed between the outer pipe and the inner pipe of the pipe section is combined with a fluid flow through the inner pipe.