WO2019034277A1

WO2019034277A1 - Exhaust gas system for a combustion engine, flange plate or bearing bush, exhaust manifold, vehicle and method for operating an exhaust gas system

Info

Publication number: WO2019034277A1
Application number: PCT/EP2018/000389
Authority: WO
Inventors: Hans Ruscheweyh
Original assignee: Ruscheweyh Consult Gmbh
Priority date: 2017-08-14
Filing date: 2018-08-03
Publication date: 2019-02-21
Also published as: DE102017007662A1; DE202017004956U1

Abstract

The invention relates to an exhaust gas system for a combustion engine, comprising an exhaust gas inlet, an exhaust gas conduit, and an exhaust gas outlet, such that exhaust gas produced in the combustion engine during the combustion operation is introduced via the exhaust gas inlet into the exhaust gas system, passes through the exhaust gas conduit in the main through flow direction, and exits from the exhaust gas conduit via the exhaust gas outlet, at least one fluid outlet for introduction of a fluid, in particular a reduction fluid, being provided inside the exhaust gas conduit. The invention further relates to a flange plate, to a bearing bush, and to an exhaust manifold. Lastly, the invention also relates to a vehicle and to a method for operating an exhaust gas system. It is essential that, with the aid of at least one mixer disc, a front edge vortex system is produced in a targeted manner inside the exhaust gas conduit, by means of which particularly efficient blending with the fluid is possible.

Description

EXHAUST SYSTEM FOR A COMBUSTION ENGINE, FLANGE PLATE OR BEARING HOLDER, EXHAUST GASKET, VEHICLE AND METHOD FOR OPERATING AN EXHAUST SYSTEM

The invention relates to an exhaust system for an internal combustion engine, a flange, in particular gasket sheet, a bearing sleeve, an exhaust manifold, a vehicle and a method for operating an exhaust system.

In the operation of internal combustion engines it comes naturally to the formation of exhaust gases. However, especially for vehicles, legislators have steadily increased the requirements for maximum permissible emission limit values in recent decades, for example with regard to the NOx content in particular. In order to meet the legal requirements, it is therefore already known and common in the exhaust system of modern vehicles, the addition of a fluid, such as a reducing agent, in particular, for example in the form of an aqueous urea solution, an ammonium hydroxide solution or in the form of gaseous ammonia etc. in order to chemically reduce in this way the proportion of undesired exhaust gas constituents, for example the NOx content in the exhaust gas by reduction, within the scope of suitable exhaust gas treatment processes. Thus, for example, with the so-called SCR process (selective catalytic reduction), good but not yet sufficient results are obtained, in particular with regard to future legal provisions. In particular, the mixing process between the added fluid and the exhaust gas seems to be in need of improvement in order to further improve the efficiency of these exhaust gas treatment processes.

The object of the invention is therefore to provide a way to improve the mixing of the exhaust gas with a within the exhaust system to the exhaust gas added fluid in an exhaust system for an internal combustion engine as possible. The object is achieved with an exhaust system for an internal combustion engine, a flange plate, in particular a gasket, a bearing sleeve, an exhaust manifold, a vehicle and a method for operating an exhaust system according to the independent claims. Preferred developments are specified in the dependent claims.

Essential elements of a generic exhaust system for an internal combustion engine are an exhaust system with an exhaust gas inlet and an exhaust outlet. About the exhaust gas inlet, the resulting during the combustion operation of the internal combustion engine exhaust gas is supplied to the exhaust system. By contrast, the exhaust gas exits the exhaust gas outlet via the exhaust gas outlet, usually to the outside environment. Between the exhaust gas inlet and the exhaust gas outlet, the exhaust gas passes through the exhaust gas guide in the direction of a so-called main flow direction, which denotes the essential flow direction of the exhaust gas through the usually not rectilinear exhaust system between the exhaust gas inlet and the exhaust gas outlet. This means within the meaning of the present invention therefore not just that the exhaust gas passes the exhaust system exclusively in a straight line and in the direction of the main flow direction. The term "main flow direction" rather expresses that the exhaust gas quite locally and / or partially within the exhaust system, for example due to turbulence and flow separation but in particular also due to the at least one mixer disk described below, different from the main flow direction within the exhaust system It is therefore essential that the global orientation of the exhaust gas across the exhaust gas duct is oriented from the exhaust gas inlet to the exhaust gas outlet.Usually the exhaust gas duct is designed as a longitudinally extending pipeline system The main flow direction runs essentially along the central longitudinal axis of the tubes Another essential element of the exhaust system according to the invention lies in at least one fluid outlet within the exhaust system, which is used to introduce a fluid into the interior of the exhaust system, i nsbesondere a reduction fluid, is provided. The fluid outlet, for example in the form of a nozzle, is connected via a suitable line to a fluid reservoir, which is arranged outside the exhaust system, for example in a manner known per se in the prior art. A typical fluid used herein is, for example, an ammonium hydroxide or urea solution.

An essential aspect of the invention consists in the fact that the exhaust system for an internal combustion engine according to the invention further comprises at least one mixer disk for generating a leading edge vortex system within the exhaust system. The at least one mixer disk thus denotes a specially for the mixing process between the exhaust gas and the fluid Functional component seen over which targeted a locally substantially stable vortex system in the form of a leading edge vortex system is generated within the exhaust system. In this case, a leading edge vortex designates a vortex which arises as a result of the flowing along of the exhaust gas at one edge or a plurality of edges at an angle to the main flow direction edge of the at least one mixer disk. This phenomenon, which is known per se, can be attributed to the fact that, in the case of an oblique approach (flow at an approach angle α to the surface plane of the delta wing) of a mixer disk, the flow at the edge of the surface is torn off, thereby producing a negative pressure area on the rear side of the mixer disk. As a result, the flow rolled in and creates a stationary vortex in the flow path. If the mixer disk is set at an angle oblique to the direction of flow and has two divergent edges starting from the tip, two mutually opposite flow vortexes can be produced at these two edges. This vortex pair is also referred to as the leading edge vortex system. The generated leading edge vortices can preferably penetrate one another, which is preferably used according to the invention for mixing. By virtue of the fact that, with the at least one mixer disk introduced into the exhaust gas guide, a front edge vortex system is produced within the exhaust system, the mixing of the exhaust gas with the fluid can be carried out under reliable and substantially reproducible mixing conditions. The at least one fluid outlet is arranged leeward to the at least one mixer disk. The fluid outlet is thus according to the invention in spatial proximity to the mixer discs. Ideally, the alignment of the jet of the fluid outlet takes place in such a way that the near-wall jet (ie the region of the jet closest to the channel wall of the exhaust passage) is aligned at least parallel to the channel inner wall of the exhaust guide in this area or at an angle ε to the interior of the channel. With respect to a channel cross-section of the exhaust system perpendicular to the flow direction, the mixer disk is preferably spaced by a factor of 0.05 to 0.3 and in particular from 0.1 to 0.2 of the length of the mixer disk of the channel inner wall of the exhaust duct, in particular completely circumferential. Additionally or alternatively, the fluid outlet with respect to the length of the mixer disk is preferably arranged leeward to the mixer disk such that it is in the range of a factor of 0.02 to 0.2 and in a plane transverse to the main flow direction of the exhaust system at the level of an edge region of the mixer disk in particular from 0.05 to 0.1 5 the length of the mixer disk. Specifically, the at least one fluid outlet is positioned relative to the at least one mixer disk such that the fluid emerging from the mixer disk enters the front eddy system generated by the at least one mixer disk for thorough mixing with the exhaust gas flowing through the exhaust pipe in the main flow direction, ideally already at the level of at least one millimeter - shear disc. It is thus essential that the fluid outlet is not positioned somewhere in the exhaust passage relative to the mixer disk, but specifically such that the exiting from the fluid outlet fluid as quickly as possible, ideally immediately after exiting the fluid outlet, in the generated by the at least one mixer disk leading edge vortex system enters, then immediately mixed with the exhaust gas. Thus, on the one hand, it is essential to use at least one mixer disk for generating a leading edge vortex system within the exhaust gas guide and, secondly, to position the fluid outlet coordinated with the leading edge vortex system generated by the at least one mixer disk in order to allow rapid entry of the fluid into the leading edge vortex system and thereby efficient mixing.

It has been found that particularly stable and relatively widely extended leading edge vortex system can be obtained if the at least one mixer disk is ideally arranged at an acute angle to the main flow direction. The relevant angle here denotes the smallest angle of a straight line running along the mixer disk surface to the longitudinal axis of the main flow direction. Additionally or alternatively, it is further preferred if the at least one mixer disk is arranged in the exhaust gas guide in such a way that its peripheral edge is completely free or at least its edge region which is flowed towards the main flow direction by the exhaust gas. This therefore means, in particular, that a holder of the at least one mixer disk preferably does not attach to an edge of the at least one mixer disk facing the exhaust gas flow or to a region of the edge which is impinged by the exhaust gas during operation of the internal combustion engine, but ideally, for example, in the surface the at least one mixer disk and / or, if at all, one of the exhaust gas flow in the main flow direction facing away from the edge region.

In order to ensure that the fluid discharged via the fluid outlet into the exhaust gas stream is mixed rapidly and as completely as possible with the exhaust gas, the opening of the fluid outlet is preferably positioned directly in front of and especially even directly in the generated leading edge vortex system. In this way, it is achieved that the fluid passes directly at the outlet from the fluid outlet in the leading edge vortex system and thus is immediately subjected to a strong mixing with the exhaust gas. The concrete position of the leading edge vortex system of the at least one mixer disk can be simulated in advance, for example, and / or determined experimentally.

[0009] As known, vortex vortices have a defined longitudinal extent as so-called flow-directed vortices, usually in the direction of their so-called longitudinal axis or vertebral axis. salmon, up. The longitudinal axis refers to an axis about which the movement of a leading edge vortex occurs. On a surface-trained mixer disk usually a Vorderkantelwirbelpaar or at each overflowed side edge in each case a leading edge vortex arises. It is now preferred according to the invention to position the at least one mixer disk of the type in the exhaust gas duct that the front eddy system or at least one of the leading edge eddies produced by it in the exhaust gas direction initially faces in the direction of the cross section center of the exhaust gas duct from an inner wall region of the exhaust gas duct is. In other words, the longitudinal axis of the leading edge vortex system or at least of the one leading edge vortex is thus initially directed at least partially from the point of origin of the leading edge vortex / system to the cross section center of the exhaust gas guide. This ensures that the exhaust gas located in the leading edge vortex system is initially not directed together with the fluid in the direction of the inner wall, but tends towards the center. In this way, buildup and deposits of parts of the fluid on the inner wall of the exhaust system is prevented.

The outlet opening of the fluid outlet is ideally positioned transversely to the main flow direction at the level of the at least one mixer disk. This means that viewed in the main flow direction, the outlet opening lies transversely to the main flow direction in the region of the extent of the at least one mixer disk and is therefore arranged at least not far behind the at least one mixer disk in the main flow direction. On the one hand, a direct entry into the leading edge vortex system produced on the mixer disks is thereby achieved particularly well. On the other hand, this makes the entire mixing arrangement of mixer disks and fluid outlet in the main flow direction can be made extremely compact.

With regard to the specific configuration of the at least one mixer disk can be used on a variety of alternative embodiments. For example, it is preferred if the mixer disk is designed as a flat disk. This is advantageous, for example, with regard to the production of the mixer disk. With regard to the contour of the at least one mixer disk can also be drawn from a wide pool of alternative embodiments. Here, in particular mixer disks with a circular, elliptical, oval, polygonal, in particular triangular or diamond-shaped, contour have proven to be preferred. The contour designates the shape of the edge surrounding the surface of the mixer disk, in particular in a projection in a reference plane. It is possible for the mixer disk to be symmetrical, at least with regard to its edge contour or its contour, in particular with respect to its arrangement. tion in the exhaust system relative to the main flow direction, form and arrange. However, asymmetrical embodiments of the mixer disks are also conceivable and encompassed by the invention. It may also be advantageous to form the mixer disks at least partially deformed three-dimensionally, in particular with a curvature or angling in their surface. With the help of such three-dimensional deformations in the surface of the mixer disks, for example, the formation of the leading edge vortex system can be adapted to design-specific characteristics of the exhaust system, for example, bends in the exhaust system, etc.

Additionally or alternatively, it is also possible, the at least one mixer disk by means of an adjusting device relative to the exhaust guide relatively adjustable, in particular displaceable and / or rotatable and / or tiltable execute. This can be achieved via a manually operable adjusting device or else a driven adjusting device, for example by means of an electric motor or the like.

With regard to the size of the mixer disks, it has been found to be preferred if the diameter of the at least one mixer disk corresponds to 0.5 to 0.7 times the diameter of the channel inner wall of the exhaust system transversely to the main flow direction in the region of the mixer disk. As a result, a front edge vortex system which is sufficiently large for a particularly efficient mixing of the fluid with the exhaust gas is created within the exhaust system, without the at least one mixer disk inserted into the exhaust gas flow constituting an adverse flow obstacle. Additionally or alternatively, the at least one mixer disk itself is preferably dimensioned such that its maximum length corresponds to 1.4 to 1.8 times, in particular to 1.6 times, its maximum width and / or its thickness is in the range of 0.003 to 0, 03 times the maximum pulley diameter. Next additionally or alternatively, it is preferred if the angle of attack of the at least one mixer disk to the main flow direction in the range of 20 ° to 35 ° and in particular at about 30 °. The dimensioning of the at least one mixer disk further takes place additionally or alternatively such that the disk surface on a flat side of the mixer disk corresponds to 0.25 to 0.5 times the area of the flow cross-sections of the exhaust gas duct transversely to the main flow direction in the region of the at least one mixer disk. Finally, it is additionally or alternatively also preferred if the fluid outlet is positioned on the leeward side such that the distance of the fluid outlet corresponds to 0.05 to 0.2 times the largest dimension of the at least one mixer disk.

For fluid supply of the fluid outlet, a fluid guide is provided, via the outside of the exhaust passage from a suitable reservoir fluid into the interior of the exhaust system to is conveyed towards the fluid outlet. Such systems are already known per se in the prior art. In addition to the completely independent design of the fluid guide to at least one mixer disk, it is also possible and preferred to integrate at least a portion of the fluid guide in the at least one mixer disk to obtain in this way a particularly compact mixing arrangement. An integration is present when the fluid guide is at least partially firmly connected to the at least one mixer discs. For this purpose, it can be provided, for example, to arrange a part of the fluid guide, in particular on the leeward side of the at least one mixer discs. Additionally or alternatively, it may also be provided that the mixer disks are double-walled with two, in particular interconnected, mixer disk walls, and that the integrated fluid guide is at least partially disposed in a space between the mixer disk walls. The sandwich-like structure then obtained also allows a particularly compact design of the entire mixing device. It can also be provided that at least two fluid outlets are present per mixer disk, with one fluid outlet being assigned to each one of the leading edge vortices produced by the at least one mixer disk. In particular, this variant allows a particularly fast and intensive mixing.

Basically, it is possible to arrange the at least one mixer disk somewhere in the region of the exhaust system. In the event that the exhaust system includes an exhaust manifold, it has been found to be particularly useful and advantageous if the at least one mixer disk is arranged in the region of the exhaust manifold, in particular such that the least one mixer disks inclined in the main flow direction to an inner curvature of the exhaust manifold is. The internal curvature denotes the curvature line of the exhaust system which lies in the interior with respect to the curvature profile. Thus, as seen in the main flow direction, the at least one mixer disk runs from the outer curvature in the direction of the inner curvature. This is advantageous in that then the leading edges of the at least one mixer disk are more likely to sit in a region with a relatively high flow velocity, which is advantageous for leading edge vortex formation. In addition, the at least one mixer disk then additionally helps to homogenize the flow velocity of the exhaust gas-fluid mixture downstream of the mixer disk. An exhaust manifold referred to herein generally such a component of the exhaust system, which is usually attached directly to the engine block, in particular screwed, and in particular, for example, the exhaust gas streams of different cylinders of the engine to the output of the exhaust manifold united. On the one hand, the exhaust manifold has proven to be a suitable location in conventional exhaust systems for introducing the fluid, in particular reducing agent. On the other hand the exhaust manifold often made as a separate component, which facilitates the integration of at least one mixer disk in this part of the exhaust system.

Also with regard to the specific embodiment of the fluid outlet different variants are possible and advantageous. Preferably, the Fiuidauslass is formed such that the main exit direction of the fluid is at an angle of 0 ° to 90 ° to the main flow direction. The main exit direction of the fluid from the Fiuidauslass designates that spatial direction of the fluid, which holds it on exit from the Fiuidauslass on average. In the said angular range, the introduction of the fluid into the front edge vortex system produced on the at least one mixer disk succeeds particularly well. It is also possible to form the Fiuidauslass such that the outlet direction of the fluid is initially directed partially directly to the at least one mixer disk. But it is also preferred if the Fiuidauslass is formed such that the outlet direction of the fluid and in particular the main exit direction of the fluid is directed exclusively in the direction away from the at least one mixer disk. In this way it is ensured that deposits of components of the fluid are avoided on the mixer discs. The Fiuidauslass can be a simple pipe opening, in particular for the injection of a gaseous fluid. However, the Fiuidauslass is preferably in the form of a nozzle, in particular a multi-phase nozzle. Such a nozzle is particularly advantageous if the fluid which is to be discharged via the Fiuidauslass, a liquid fluid, for example, an aqueous urea or ammonium hydroxide solution. By means of a nozzle, it is possible to atomize the escaping fluid in the exhaust system and to facilitate in this way the mixing with the exhaust gas. In addition, deposits are reduced and the evaporation process promoted.

Overall, it can be provided that the at least one mixer disk is assigned exactly one Fiuidauslass. This means that, in the first eddy vortex system produced by the at least one mixer disk, at least initially, the fluid emerging from the one single fuel outlet is primarily mixed with the exhaust gas. It can also be provided that a plurality of mixer disks, in particular at least two, are assigned exclusively to a single Fiuidauslass. Seen in the main flow direction, the two mixer disks can be arranged behind one another or next to one another. In a successive arrangement, it is advantageous if the Fiuidauslass is positioned at the height of the upstream of the main flow direction mixer discs. On the other hand, if the two mixer disks are arranged next to one another, an arrangement of one fluid outlet to one mixer disk may alternatively (exclusively or in addition) be an arrangement of a fluid outlet. be provided in the area and at the height between the two mixer discs. However, particularly good mixing results can also be obtained if the at least one mixer disks are assigned a plurality of fluid outlets, in particular only two. This means that the fluid emerging from the plurality of fluid outlets is substantially at least initially mixed with the exhaust gas, at least initially by the leading edge vortex system generated with the at least one mixer disk. It is ideal if in each case one of the two fluid outlets is assigned in each case to one of the two front edge vortex systems produced by the mixer disk. The leading edge vortices are usually generated at the transverse to the main flow direction edges of the mixer discs. The at least one mixer disk thus generally generates at least two leading edge vertebrae, which in their entirety form a leading edge vertebra system. The term leading edge eddy system in the present case thus denotes the sum of the leading edge vertebrae which are generated on a mixer disk. When using, for example, only two fluid outlets per mixer disk, it thus makes sense to position one fluid outlet in each of the two leading edge vortices.

In principle, different variants can be used in terms of the number of mixer disks in the exhaust system. So it may be sufficient that only a single mixer disk is arranged in the entire exhaust system, or is used on multiple mixer disks. These can be identical to each other or can be designed differently. In view of the space conditions usually prevailing in the exhaust system of the exhaust system for an internal combustion engine, it has been found to be particularly advantageous to use only two mixer disks in the entire exhaust system, in particular in the region of a common mixing stage. This allows particularly good results with a simultaneously comparatively simple construction of the entire mixing device, comprising at least one fluid outlet and the two mixer disks.

The at least and in particular exclusively two mixer disks can be arranged parallel to one another, in particular with respect to a virtual reference plane in the direction or transversely to the main flow direction. However, it is also possible that the two mixer discs are tilted at an angle to each other, in particular at an acute angle. This arrangement may be advantageous in particular when the at least two mixer disks are arranged in a section of the exhaust system, in particular an exhaust manifold. The effect that the flow velocity of the exhaust gas is higher in the region of the outer curve of the bend ("outer curvature") than in the region of the inner curve can then be exploited to particular advantage. Shear disks transverse to the main flow direction at the same height to arrange. The two mixer disks are then positioned side by side as seen in the main flow direction, in particular parallel to one another. Alternatively, the two mixer disks can also be arranged offset in the main flow direction at least partially or completely one behind the other. This corresponds to an arrangement of the two mixer disks in series. Mixed forms, especially when using more than two mixer disks, are possible. Furthermore, each of the at least and in particular exclusively two mixer disks can each be assigned at least one outlet nozzle and in particular only one or two outlet nozzles. In this way, the mixing efficiency can be further increased without unduly complicating the overall structure of the mixing device. The at least and in particular exclusively two mixer disks can finally be identical or also differently designed with respect to size and / or shape. Here, in particular, it is possible to react to construction-specific peculiarities by means of an optimized shaping of the mixer disks.

Further advantageous variations of the invention finally arise in relation to the nature of the attachment of the mixer disks in the interior of the exhaust system. For this purpose, it is provided that the at least one mixer disk is preferably arranged via a fastening device within the exhaust system and is held in position. The fastening device can also be varied considerably in its concrete embodiment advantageously. It is possible, for example, to position the least one mixer disk in the exhaust gas guide in a particularly simple manner such that the fastening device comprises a strut guided through a wall of the exhaust gas guide, in particular on both sides, wherein the at least one mixer disk with the strut, either with its surface or via a connecting web projecting from the strut. Such a strut can be executed in the simplest case, for example as a wire '. For this variant, two through-openings can thus be present in the exhaust gas duct, through which the strut is guided from the interior of the exhaust gas duct to the outside. Alternatively, it can also be provided that the fastening device comprises at least one support element, which is designed to bear on an inner wall of the exhaust gas guide. The support element thus abuts against the inner wall of the exhaust gas duct directly and is fixed in its relative position to the rest of the exhaust gas duct via, for example, suitable interlocking, cohesive or frictionally engaged connections. Further, a holding element is preferably present, via which the least one mixer disk is connected to the at least one support element. The support element may, for example, be two or more clamping webs or the like which are in contact with one another and bear against the inner wall of the exhaust gas duct. In particular, It is also possible in particular for the fastening device to comprise a bearing sleeve and / or clamping sleeve, in the inner region of which the at least one mixer disk is mounted and connected directly or via a retaining element to the bearing sleeve. For the latter, for example, again a guided inside the sleeve strut or the like may be provided. The outer diameter of the bearing sleeve is preferably dimensioned such that it is only minimally smaller than the inner diameter of the exhaust system in the desired positioning range. The bearing sleeve may be partially elastic, for example in the form of a clamping or clamping sleeve, be formed to be inserted in this way, for example, in the exhaust system and then held there by frictional engagement. Additionally or alternatively, the fastening device may also have a flange plate with a passage opening, wherein the at least one mixer disk is preferably positioned at the level of the passage opening and is connected directly or indirectly via a holding element with the flange plate. The flange plate can in particular also be a, very particularly metallic, flat gasket, which is inserted between two components of the exhaust system, in particular an exhaust manifold and a pipe section connected thereto, for sealing purposes. In particular, it is also possible to obtain the flange plate and the at least one mixer disk as a one-piece component from, for example, a stamped preform, wherein it is then provided that the at least one mixer disk is rotated from the preform into its desired position relative to the remaining flange sheet. In a further alternative embodiment, the mixer disk is part of a pipe intermediate piece which is inserted into the exhaust gas duct. In this variant, the mixer disk is thus not inserted via a suitable holding device in an existing pipeline, but forms itself a part of a pipeline of the exhaust system. Ideally, the fastening device is arranged in the exhaust system of the exhaust system such that it is positioned substantially stationary via a welding, clamping and / or positive connection.

Another aspect of the invention resides in a flange plate per se, in particular in the form of a flat gasket, and in a bearing sleeve per se with at least one mixer disk, in particular for use in an exhaust system, as described above. With respect to the specific embodiment of the flange plates and the bearing sleeve and the mixer disk, reference is made to the preceding embodiments. These items are particularly suitable for retrofitting. The fluid outlet may also be included or separately provided. If the fluid outlet is also included, the flange plate or the bearing sleeve also has a connection for connecting the fluid outlet to a fluid supply. The invention may also consist of a pipe adapter with at least one mixer disk of the type described above, preferably already comprising the fluid outlet. In contrast to the flange so here a piece of pipe is used as a supporting body for the at least one mixer disk, wherein the pipe section ideally comprises an input-side flange and an output-side flange, via which a fastening can be carried out at suitable connection points of a rest of the exhaust system. This variant is also particularly suitable for retrofitting an existing exhaust system, since essentially only one sub-region corresponding to the pipe intermediate piece has to be separated from the existing exhaust system for installation. Furthermore, this variant is particularly advantageous in terms of maintenance and accessibility to the mixing system

The invention also extends to an exhaust manifold per se with at least one mixer disk, in particular for an exhaust system according to the invention. It is therefore advantageous to design the exhaust manifold from the factory with at least one mixer disk, since then with the installation of the exhaust manifold in the exhaust system and at the same time the at least one mixer disk is positioned and held in the exhaust system. The fluid outlet may also be included or separately provided. If the fluid outlet is included, the exhaust manifold furthermore has a connection for connecting the fluid outlet to a fluid supply

The invention also relates to a vehicle, in particular a self-propelled vehicle, such as a car and / or a work machine, in particular with driving devices, such as wheels and / or crawler tracks. Essential elements of such a vehicle are an internal combustion engine, for example a diesel engine, a chassis, in particular comprising a machine frame, on which the internal combustion engine is mounted, an exhaust system connected to the internal combustion engine, a fluid tank for a fluid, in particular for the exhaust gas treatment, very particularly a reducing fluid, such as an aqueous urea solution, an ammonium hydroxide solution or the like, especially for use in an SCR process, and a fluid outlet connected to the fluid tank and opening into the interior of the exhaust system. The connection can be obtained for example via a suitable hose and / or pipe. In order to improve the mixing of the exhaust gas with the fluid, in particular to shorten the required mixing distance within the exhaust system, it is provided that the vehicle is equipped with an exhaust system according to the invention with at least one mixer disk, as described above. With respect to the specific embodiment of the invention measured exhaust system is referred to the preceding embodiments. By means of the invention, for example, a considerably more efficient use of the available vehicle-mounted th amount of fluid for injection via the fluid outlet possible, so that, for example, operating costs can be reduced. Furthermore, for example, night refueling intervals can be extended

Finally, the invention also relates to a method for operating an exhaust system, in particular an exhaust system according to the invention, an internal combustion engine, in particular a self-propelled vehicle according to the invention. In a first step, the internal combustion engine is initially driven by burning a fuel, for example diesel, in particular for driving a crankshaft in a manner known per se, for example for operating a traction drive and / or drive for a working tool. In this case, exhaust gases accumulate, which are collected in a next step and guided away from the internal combustion engine in an exhaust system according to the invention, in particular according to the invention. The collecting of the exhaust gases from the various cylinder chambers can be carried out in particular via an exhaust manifold connected to the internal combustion engine. For guiding the exhaust gas, the exhaust system comprises in particular pipelines or similar devices, via which a reliable forwarding of the exhaust gases is possible. It is essential that when guiding the exhaust gas in the exhaust gas layer according to the invention generating a substantially static leading edge vortex system is provided with at least one mixer disk in the exhaust gas within the exhaust system. For this purpose, the at least one mixer disk is arranged in the flow channel of the exhaust gas within the exhaust gas duct in such a way that it constitutes a flow obstruction for the exhaust gas, as described above in the context of the description of the exhaust gas system according to the invention. The essentially static leading edge vortex system generated when the at least one mixing disk in the exhaust gas flows through the mixer disk has the advantage that it is comparatively clearly defined and fixed with respect to its position within the exhaust gas guide, as is the case with an uncontrolled turbulent turbulence A readjustment of the at least one mixer disk is also not necessary since the size and position of the mixer disk are set ex works, which in a next step of the method according to the invention makes it possible to introduce a fluid, in particular reducing fluid, specifically into the leading edge vortex system, in particular via the one already explained above Due to the substantially direct introduction of the fluid into the leading edge vortex system, intensive mixing with the A moved in the leading edge vortex system takes place immediately after the release of the fluid in the exhaust gas guide The mixing of the fluid with the exhaust gas in the leading edge vortex system is thus likewise an essential aspect of the method according to the invention. As a result, the required for a homogeneous and particularly rapid mixing between the exhaust gas and fluid mixing section can be kept relatively short inside the exhaust system, which is also advantageous in the operation of a generic exhaust system. Overall, that allows inventive method with relatively little design effort a very efficient and also over a wide operating range of the internal combustion engine reliable mixing of the exhaust gas with the fluid, so that, for example, the effectiveness of an ongoing SCR process can be significantly increased.

Preferably, the inventive method is such that the generation of the leading edge vortex system provides that the vortex is directed from the direction of the inner wall of the exhaust system initially to the cross-section center of the exhaust system out. The orientation of the vortex refers to its central vortex axis, starting at the maximum upstream point of origin of the leading edge vortex system on the mixer disk. This means that fluid introduced into the leading edge vortex system is initially transported away from the inner wall of the exhaust gas guide in the direction of the cross section center of the exhaust gas guide. In this way, a deposition of components of the fluid is counteracted on the inner wall of the exhaust system.

The inventive method may additionally or alternatively be further developed such that an adjustment of the relative position of the at least one mixer disk relative to an inner wall of the exhaust system takes place, in particular, for example, depending on different operating conditions of the internal combustion engine. In this way, it is possible to react to changes in the flow characteristic, for example with regard to the flow velocity, of the exhaust gas in the exhaust gas duct.

In principle, recourse may be had to the implementation of the method according to the invention to the entire area of the exhaust gas routing. However, the generation of the leading edge vortex system preferably takes place in an exhaust manifold and thus in such a part of the exhaust system in which the exhaust gases produced in the internal combustion engine are collected and combined. Among other things, this position is advantageous in that the exhaust manifolds used here are often already provided as a single component, which simplifies the integration of the at least one mixer disk into an exhaust system for carrying out the method according to the invention.

The invention will be explained in more detail with reference to the embodiments specified in the figures. It show schematically

Figure 1: a schematic view of a vehicle with an internal combustion engine and a

Exhaust system; FIG. 2 shows a detail view of the exhaust gas duct in the region of a mixer disk;

Figures 3A and 3B are schematic illustrations of the generation of a leading edge vortex system on two different mixer discs;

FIG. 4: plan views of different shapes of possible mixer disks;

FIG. 5: top view of further variants of mixer disks;

FIG. 6: side views of different variants of mixer disks;

FIG. 7 shows exemplary alternatives to the relative arrangement of two mixer disks relative to one another;

FIG. 8: flow alternatives of exhaust gas and fluid on a mixer disk;

FIG. 9: outflow variants of the fluid relative to a mixer disk;

FIG. 10: mixer disk with integrated fluid guide and integrated fluid outlet;

Figure 1 1: Verstellbarkeitsbeispiele a mixer disk;

Figs. 12A and B show alternative introduction of the fluid into a leading edge eddy system;

FIG. 1 3: Arrangement alternatives of a plurality of fluid outlets relative to a pair of mixer disks;

FIGS. 14A to 14D show two attachment alternatives in plan view and in side view;

Figures 1 5 A and 15 B: Sectional views of an exhaust system with a mixer disk in one

Bearing sleeve;

FIGS. 16A and 16B: sectional views of an exhaust system with a mixer disk in one

Clamping device;

Figures 1 7 A and 1 7 B: Sectional views of an exhaust system with a mixer disk in one

flange plate;

Figure 1 8: schematic view of an internal combustion engine with connected exhaust system with

SCR system; FIGS. 19A and B are sectional views of a curved region of the exhaust system with one or two mixer disks;

FIG. 20 shows a side view of a mixer disk within an exhaust system with a generated front edge vortex system;

FIG. 21: flow diagram of a method according to the invention;

FIG. 22: side view of a further fastening alternative;

Figure 23: side view of an arrangement with a pipe adapter; and

FIG. 24: Top view of a mixer disk with two outlet slots.

Identical or functionally identical components are denoted by the same reference numerals in the figures, wherein not every repeating component in the figures is necessarily marked in each figure.

Figure 1 initially illustrates the basic structure of a vehicle 1 in a highly schematic view. The vehicle 1 comprises a chassis 2, an internal combustion engine 3 and an exhaust system 4 connected to the internal combustion engine 3. The exhaust system 4 comprises an exhaust gas inlet 5, in this case divided into four individual inlets, which are each assigned to a cylinder of the internal combustion engine 3 (FIG one of these exhaust gas inlets 5 denotes), an exhaust gas guide 6 and an exhaust gas outlet 7, via which the exhaust gas guided in the exhaust gas guide 6 exits the exhaust gas guide 6 into the outside environment. In the present exemplary embodiment, the exhaust gas guide 6 comprises an exhaust manifold 8, pipe sections 9 and an optional mixing chamber 10, the latter also being designed as a pipe section 9 with the mixing device with mixer disk described in more detail below. The number and specific design of the elements 8,9 and 10 may vary by design. However, the exhaust manifold 8 is preferably formed as a continuous individual component. The elements 8, 9 and 10 are connected to one another via suitable connections, for example welded and / or flange connections, for obtaining the exhaust system 4 or are formed as a whole in one piece. The path of the resulting during operation of the internal combustion engine 3 exhaust gas is indicated in the figures by solid arrows, which ultimately indicate the Hauptdurchströmungsrichtung B of the exhaust gas within the exhaust passage 6 from the exhaust gas inlet 5 to the exhaust outlet 7. The exhaust system 4 further comprises two fluid outlets 11, in the present embodiment, within the mixing chamber 10. The fluid outlets 1 1 are connected via supply lines 12 with an unspecified fluid reservoir within the vehicle 1. Fluid, in particular a reducing fluid, for example an aqueous urea solution, is introduced via the fluid outlets 11 as a reductive component of an SCR process for reducing the proportion of NO x in the exhaust gas into the exhaust gas guide 6 from outside the exhaust gas guide 6. In order to achieve efficient mixing of the fluid with the exhaust gas, at least one mixer disk 13 is introduced into the exhaust gas guide 6, in the present exemplary embodiment a mixer disk pair 13 arranged tilted opposite one another. Using the mixer disks 13, leading edge vortex systems are generated within the exhaust gas flowing through the exhaust gas guide 6 be used for efficient mixing of the exhaust gas with the exiting the fluid outlets 1 1 fluid.

The effect of the mixer disks 13 is illustrated in more detail in the longitudinal sectional view according to FIG. The mixer disk 1 is shown there in a pipe section 9 with the pipe diameter D. The main flow direction B extends in Figure 2 from left to right. The plate-shaped and shown in side view plane mixer discs 13 is tilted at an acute angle α (in the present case about 30 °) relative to the main flow direction B. The fluid outlet 11 lies correspondingly on the downstream side or on the leeward side of the mixer disk 13. When viewed in the main flow direction B, the mixer disk 13 also extends over the region E. The fluid outlet 11 is viewed transversely to the main flow direction B within this region E and thus on Height of the mixer disk 13 is arranged. The mixer disk is thus seen in the main flow direction B "in the area" of the mixer disk 13. If the exhaust gas flows from the left past the mixer disk 13, this leads to the generation of a leading edge vortex system 14. The vortex axis W of the two leading edge vortices generated thereby is exemplary in FIG 2 illustrates the positioning of the fluid outlet 11 within the generated leading edge vortex system 14, so that the fluid leaving the fluid outlet 11 (dashed arrows in the figures) in the present case directly and directly into the leading edge vortex system 14 is discharged and is immediately subjected to an efficient mixing with the exhaust gas within the exhaust duct 6.

In Figures 3A and 3B, the specific embodiment of the leading edge vortex system 14 is illustrated even more clearly on the basis of two different mixer disks 1 3. V1 denotes the direction of flow or the main flow direction B to the mixer disk 1 3. With α is the angle of attack of the mixer disks 13 with respect to the main flow direction B / V1 specified. FIG. 3A shows a mixer disk 13 in the form of an isosceles triangle (delta surface), the tip of which flows from the exhaust gas coming from the main flow direction B. In this case, the leading edge eddy system 14 is generated with the two opposite to each other rotating leading edge vortices 14A and 14 B at each one of the longitudinal edges of the mixer discs 1 3. The leading edge vertebrae 14A and 14B each have one of the vertebral axes W1 and W2. The vortex axes W1 and W2 extend substantially away from the mixer disk 13 in the main flow direction B. FIG. 3B shows the formation of a substantially corresponding leading edge vortex system on an oval shaped mixer disk 13

In the specific embodiment of the mixer disks 1 3 can now be used on a variety of alternative embodiments. In FIG. 4, different variants are given by way of example for this purpose, wherein the list shown there is expressly not to be understood as conclusive within the scope of the invention. In FIG. 4, planar, planar mixer disks 13 are assumed in each case, which differ from one another in the design of their outer contour or their shape. Thus, for example, circular (FIG. 4A), oval (FIG. 4B), triangular (FIG. 4A), in particular in the form of an isosceles triangle (delta surface), quadrangular (FIG. 4D), in particular diamond-shaped or square, or also other polygonal mixer disks are possible 1 3, as for example also octagonal (Figure 4E) mixer discs 13. With the targeted selection of the shape of the mixer discs 13 can be responded in particular, for example, to design-specific features.

Further variations are possible, for example, with regard to the symmetry design of the mixer disks 13. In particular, symmetrically designed mixer disks are possible, as indicated in FIG. The mixer disk 13 formed there as an isosceles triangle comprises the axis of symmetry S. However, unsymmetrical mixer disks 13 can also easily be used, as shown by way of example in FIG. 5B with the quadrangular mixer disks 13 shown there. The symmetry design provides a starting point, for example, to respond to the specific operating environment of the mixer disks 1 3 by appropriate shaping. It should also be taken into account that particularly well uniform vortex systems can be produced by means of symmetrical mixer disk shapes in the main flow direction.

The mixer disks 13 used in the present case can be formed in particular as planar elements, as illustrated in the side view on a mixer disks 13 in Figure 6A. In these embodiments, the mixer disk 13 thus extends substantially in one Level. However, the mixer disks 13 used can also be deformed three-dimensionally. For this purpose, for example, simple folds (FIG. 6B), multiple folds (FIG. 6C) and / or bending deformations (FIG. 6D) of the mixer disks 13 are possible. Also via the three-dimensional shaping of the mixer disks 13, an optimization of the generated leading edge vortex system can be achieved to the respective existing operating conditions within the exhaust system.

In principle, it is also possible that only a single mixer disk 13 is provided in the exhaust gas guide 6, as shown for example in Figure 2. However, it can also be provided that a plurality of mixer disks are combined with each other, wherein the mixer disks 13 can be designed to be similar or different. The mixer disks 13 can furthermore be arranged behind one another or alongside one another in the main flow direction B. FIGS. 7A and 7B exemplarily illustrate two alternative arrangement possibilities of two mixer disks 13 relative to one another. In the exemplary embodiment according to FIG. 7A, the two mixer disks 13 are arranged at the same height and parallel to one another. In the embodiment according to FIG. 7B, by contrast, the two mixer disks 13 are tilted relative to one another at an angle β, wherein they are contactless relative to one another. Such a tandem arrangement leads to particularly good mixing results and also makes it particularly well possible to adapt the entire mixing device to the respective geometric conditions in the exhaust gas duct. In the specific case, the two mixer disks 1 3 are further arranged such that the rear in the flow direction B mixer disk intersects the front in the flow direction mixer disk 13. It can be particularly advantageous if only two mixer disks 13 are arranged in the entire exhaust gas guide 6, as shown for example in FIG.

FIGS. 8A to 8D illustrate, by way of example, various variants of how the fluid can be oriented relative to the main flow direction B and to the mixer disk 1 3 by a corresponding configuration of the fluid outlet described above. The main direction of movement, which holds the fluid exiting the fluid outlet 11, is denoted by C in FIGS. 8A to 8D. In the embodiment of Figure 8A, the fluid flows in the direction of arrow C perpendicular to the main flow direction B of the exhaust gas obliquely in the direction of the leeward surface of the mixer discs 13. In the embodiment of Figure 8B, the fluid flow is perpendicular to the lee side of the mixer disc 13 and thus partially opposite to the main flow direction B aligned. In FIG. 8C, the fluid flows in the opposite direction of the main flow direction B obliquely to the leeward side of the mixer disks 13 and in FIG. 8D on the leeward side of FIG the mixer disks 1 3 away in the main flow direction B. The listing shown here is merely exemplary and not to be understood as exhaustive. In practice, it turns out that the variant according to FIG. 8 (A) is particularly well suited for the admixture of gaseous fluids into the exhaust gas flow, whereas for liquid fluids ideally the variant according to FIG. 8 (D) is used.

In principle, it is possible that the fluid exits not only as a directed beam, but, for example, when using appropriate nozzles, fan-shaped from the fluid outlet 1 1. It is possible, the fluid outlet 1 1 to be arranged such that only a portion of the exiting fluid is aligned in the direction of the mixer disk 1 3, as shown in the embodiment of Figure 9A. However, it is also particularly favorable if the fluid outlet 11 is designed and arranged such that the fluid emerging from the fluid outlet 11 is directed completely in the direction of the mixer disk 13, in particular on the leeward side thereof, as shown in FIG illustrated. This listing is not meant to be conclusive.

In the previous embodiments, the fluid outlet 1 1 and the mixer disks 13 are each arranged spatially separated from each other. However, it is also possible to combine these two elements together in a structural unit and to integrate at least part of the supply line 12 in the mixer disk 1 3, as explained in more detail in the embodiment of FIG. The there double-walled with the disk walls 1 3A and 1 3B trained mixer disks 1 3 comprises in its between the two mixer disk walls 1 3A and 1 3B formed intermediate space 1 5 a part of the supply line 12, via two introduced into the mixer disk wall 13A fluid outlets 1 1 to the outside and open in the installed state in the interior of the exhaust system. The two fluid outlets 1 1 are seen in the main flow direction B successively arranged and offset from one another. This allows a particularly compact overall arrangement of mixer disk 1 3, fluid outlet 1 1 and part of the supply line 1 2. Again, other alternatives are possible. For example, the doppelwandi- ge configuration of the mixer discs 13 is not mandatory. It can also be provided that a part of the supply line takes place on a surface side of the mixer disks 13, in particular the leeward side (not shown in FIG. 10).

The mixer disk 1 3 can be stored statically and thus in their relative position within the exhaust passage 6 stationary. However, it may also be desirable to make the mixer disk 13 adjustable relative to the exhaust gas guide 6 in order, for example, to make changes in the positioning of the mixer disks 1 3 within the exhaust gas guide 6, depending on the operation. This may be desired, for example, when a bypass exhaust gas flow is activated, which changes the main exhaust gas flow in the region of the mixer disk 13. The scope of motion spectrum of the mixer disks 13 is illustrated by way of example in FIG. 11. The initial position of the mixer disks 13 is illustrated in FIG. 11 by the solid line of the mixer disks 13. In dashed lines, other possible end positions are indicated starting from this position. For example, it may be provided to make the mixer disk 13 displaceable. 1 1, for example, a linear displaceability along the arrow I is indicated perpendicular to the main flow direction B and along the arrow II in and counter to the main flow direction B. The mixer disk 13 can also be pivotable about a pivot point D1 in the direction of the arrow III about an axis extending transversely to the main flow direction B. Alternatively, the rotation can also take place via a pivot point D2 in the surface of the mixer disk 13 in the direction of arrow IV. Of course, further options are also conceivable here and included in the invention. For example, it may also be provided that the mixer disk is rotatable about an axis running parallel to the main flow direction B. The concrete triggering of the rotational movement can take place via a controlled and / or manually operable adjusting device, not shown in greater detail in FIG. 11, which attaches, for example, to one of the pivot points D1 or D2.

FIGS. 12A and 12B show preferred relative arrangements between a plurality of fluid outlets and the front edge vortex system 14 formed on the mixer disk 13. In FIG. 12A, exactly one fluid mixer disk 13 is associated with two fluid outlets 1 1A and 1 1 B, such that one each the two fluid outlets 1 1A and IIB are assigned to one of the two leading edge vertebrae 14A and 14B of the leading edge vertebra system 14. This means that the fluid emerging from the fluid outlet 1 1A is first almost completely mixed in the leading edge vortex 14A and the fluid leaving the fluid outlet IIB is first almost completely mixed in the leading edge vortex 14B with the exhaust gas. Of course, it comes in the course of mixing these two systems with each other, so that the present separation on the one hand not necessarily quantitative and especially not to understand the entire extent of the exhaust system. The development is directly in the main flow direction B following the respective fluid outlet 11 A and II B. In contrast to this, it is provided in the exemplary embodiment according to FIG. 12B that the fluid supplied via a common feed line of a mixer disk 13 is divided between the two leading edge vortexes 14A and 14B becomes. The distribution of the exiting fluid can be achieved for example by means of a spread nozzle, a double nozzle or the like. FIG. 13 shows a plan view of a longitudinal sectional view through a region of the exhaust gas guide 6. In the present exemplary embodiment, two round mixer plates 13 are positioned side by side in the exhaust gas guide 6 relative to the main throughflow direction B. Coming from the outside, a supply line 12 extends into the interior of the exhaust gas guide 6. There, a total of five fluid outlets 11 A to 11 E are distributed along the supply line 12. Each of the two mixer disks 13 are each associated with two adjacent fluid outlets (11 A and 11 B or 1 1 D and 1 1 E) which are arranged offset to the respective edge region of the respective mixer disks 1 3. In addition, with the further fluid outlet 1 1 C, a fluid outlet in the intermediate region (transverse to the main flow direction B) of the two juxtaposed mixer disks 13 is present. With the aid of this overall arrangement, a particularly fast and efficient distribution of the fluid within the cross section of the exhaust gas guide 6 is achieved.

Further variations of the invention exist in particular also with regard to the concrete attachment or storage of the mixer disks 13 within the exhaust system 6. In this aspect, in particular Figures 14-1 7.

In Figure 14A (longitudinal section along the exhaust guide 6 and top view of the mixer disk 1 3) is a holding strut 16, for example in the form of a wire, is present, which extends transversely to the main flow direction B through the interior of the exhaust gas guide 6. At this, the mixer disk 1 3 via a transverse thereto bearing web 1 7, which connects the mixer disk 13 with the support strut 16, mounted in the interior of the exhaust duct 6. This results, for example, from the longitudinal sectional view along the exhaust gas guide 6 and from the side view on the mixer disk element 13 according to FIG. 14 B. Several wires per mixer disk 13 can also be provided for fastening. This is indicated in FIG. 14A with the dotted support strut 16 '.

In contrast, in the second embodiment according to the figures 14 C and 1 D, the support strut 16 as a pipe section of a supply line 12 with integrated fluid outlet 1 1 is formed. In this embodiment, the mixer disk 13 is connected directly to the retaining strut 16.

An alternative mounting option show the figures 15A (longitudinal sectional view along the exhaust gas guide 6 in side view of the mixer plate 13) and 15B (view against the main flow direction B). There, a bearing sleeve 18 is arranged in the interior of the exhaust gas guide 6 as an essential element. The hollow cylinder in the present embodiment Shaped bearing sleeve 18 comprises on its inner wall a radially projecting from the inner surface to the center bearing web 17 to which the mixer disk 13 is attached. The bearing sleeve has one of the longitudinal extent of the mixer disk 13 in the main flow direction B substantially corresponding cylinder height H. However, in particular it can also protrude in one or both sides in or against the direction of the main flow direction B with respect to the mixer disks or be made narrower. The concrete fixation of the bearing sleeve 18 within the exhaust guide 6 takes place for example via between the outer circumferential surface of the bearing sleeve 18 and the inner wall of the exhaust guide 6 arranged welding or soldering points, by frictional engagement or the like.

A similar construction shows the arrangement of Figures 16A and 16B. Instead of a bearing sleeve 18, two half shells 19 A and 19 B are provided here, which are connected to one another via a bearing web 1 7 running through the interior of the exhaust gas guide. In the central region of the bearing web 17, the mixer disk 13 is arranged. Alternatively, the two half-shells 19A and 19B may also be connected to one another on one side, for example, in order to obtain a kind of clamping sleeve via which the mixer disk 13 can be positioned in the interior of the exhaust gas guide 6 by frictional engagement.

An alternative approach is followed by the embodiment according to FIGS. 17A and 17B. From the longitudinal sectional view along the exhaust gas guide 6 according to FIG. 7A, it is initially clear that the now relevant region relates to the connection point of two individual components 6A and 6B of the exhaust gas guide 6. These are connected to one another via a flange connection 20 (details of the flange connection, such as screw connections, etc., are not shown in FIG. 17A). Clamped in the flange 20 is a flange 21, for example in the form of a metallic gasket or the like. The annular disk-shaped flange 21 is shown in Figure 1 7B in plan view. In the flange 21 a plurality of through holes 22 are provided through which, for example, fastening screws of the flange 20 can be performed. Inwardly to the centric and in the installed state of the exhaust gas flowed through opening 38 is from the circular flange plate 21 on one side a bearing web 1 7 radially before, which connects the flange plate 21 with the mixer disks 13. It is also possible, the flange 21 in one piece, with or without bearing web 1 7, with the mixer disk 1 3, for example as a stamped part, form and adjust the mixer disk 13 by, for example, bending in the desired relative position to the rest flange 21. Figure 18 now illustrates the basic structure of an SCR system 23 with a mixer disk according to the invention 13. Essential elements of the SCR system 23 are a NOx sensor 24, a control unit 25, a fluid tank 26, a conveyor 27, signal lines 28 and the fluid outlet 11. The control unit 25 is connected via the signal lines 28 with the internal combustion engine 3, the NOx sensor 24 and the conveyor 27, for example, a fluid pump in combination. By way of the sensor arranged upstream of the mixer disk 13 in the exhaust gas duct, it is possible, for example, to determine directly or indirectly a NOx load of the exhaust gas. In the main flow direction B downstream of the sensor 24, the arrangement of fluid outlet 1 1 and mixer disk 13 is arranged in the exhaust system, via which the fluid stored in the fluid tank 26, in particular reducing fluid, such as an aqueous urea solution, from outside the exhaust system into the interior of the exhaust system. 6 is conveyed to the fluid outlet 1 1. There takes place in the discharge of the fluid immediately intensive mixing of the fluid with the exhaust gas using the generated by the mixer disk 13 leading edge vortex system. It can also be provided that the control unit 25 controls an adjusting device with which the relative position of the mixer disk 13 can be varied within the exhaust gas duct.

The exhaust gas guide 6 often has in addition to rectilinearly extended regions in particular curved portions, for example, in particular frequently in the region of the exhaust manifold, as shown in Figures 19A and 19B, which relate to a section of a curved portion of the exhaust passage 6 in the exhaust manifold 8. In the exemplary embodiment according to FIG. 19A, two mixer disks 1 3 are arranged one behind the other in the main flow direction B. For arranging the fluid outlet 11, as an alternative to the exemplary embodiment shown, it is also possible, for example, to resort to an arrangement according to FIG. The curved region has an inner curve 29 and an outer curve 30. It is now provided that the mixer disks 13 are arranged such that their upstream located start region 31 in the direction of the outer curve 30 and its downstream end portion 32, however, oriented towards the inner curve 29 out. In other words, the distance to the outer curve 30 of the exhaust gas guide 6 in the initial region 31 of the respective mixer disk 13 is smaller than the distance of the respective end region 32 of the mixer disk 1 3. The opposite applies to the outer curve 30. The relevant here distance is measured in each case along a vertical S1 and S2 to the inner wall of the outer curve 30 or in the curves 29, as shown in Figure 20 with the vertical S1 and S2 to the outer curve 30 exemplified. In this way, speed differences in curved regions in the exhaust gas can be utilized for the particularly efficient formation of stable leading-edge vortex systems. For this purpose, FIG. 19B shows a further alternative with only a single mixer disk 13. With regard to the specific arrangement of these a mixer disk 13 is made to the comments on the embodiment of FIG. 19A reference.

Figure 20 illustrates first that it is preferred if the diameter of the mixer plate 13 and the longitudinal extension D1 is smaller than the diameter D2 of the exhaust gas guide 6, in particular in the ratio 1, 4: 1 to 2: 1 (D1: D2 ). In Figure 20, the mixer disc 13 is further arranged such that the leading edge vortex 14A is oriented from the lower inner wall portion of the exhaust system initially in the direction of the center M of the exhaust system. If the fluid entry takes place, for example, at the level of the mixer disk 13, as also shown in FIG. 2, the discharged fluid is thus first mixed with the exhaust gas in the direction of the center of the exhaust gas duct and is not directed directly to an inner wall area. In this way, deposits of constituents of the fluid on the inner wall of the exhaust gas guide 6 can be counteracted.

FIG. 21 shows a flow chart of a method according to the invention. For this purpose, it is provided that first an operation of an internal combustion engine takes place via a combustion process in step 33, whereby exhaust gases are produced and, in particular via an exhaust manifold, pass into an exhaust gas duct. There, in step 34, the collecting and guiding of the exhaust gas in an exhaust system, in particular as explained in the preceding figures. In step 35, a generation of a substantially static leading edge vortex system with respect to its extent is provided with at least one mixer disk, in particular by means of one of the arrangements described in the preceding figures. In addition, in step 36, the introduction of a fluid, in particular reduction fluid, in the leading edge vortex system, in particular via a fluid outlet. With the aid of the generated leading-edge vortex system, an extremely efficient mixing of the fluid with the exhaust gas is now possible in step 37, in particular within a comparatively short mixing section.

It is preferred if the generation of the leading-edge eddy system takes place with an arrangement, as shown, for example, in FIG. Further supplementary method steps may consist in adjusting the relative position of the at least one mixer disk relative to an inner wall of the exhaust system, for example rotationally and / or translationally. The generation of the leading edge vortex system ideally takes place within an exhaust manifold.

Fig. 22 shows a further embodiment that the holder of the mixer disk 13 can be used simultaneously as a supply line or fluid guide 12 for the fluid outlet 1 1. For this purpose, the holding element 1 7, for example, at least partially and in particular fully. be constantly formed as a channel or conduit, the / at its output end, the fluid outlet 1 1 and to the / the further the mixer plate 13 is connected, for example via a welded connection. The holding element 1 7 thus comes here a double function (holding and forwarding).

Fig. 23 shows a further possibility of mounting the mixing disk in the exhaust system. In the exemplary embodiment according to FIG. 23, 7 A instead of a flat gasket is used in particular in comparison to the similarly mounted embodiment according to FIG. 1 to a pipe adapter 39 for holding the mixer disk 13 and the fluid outlet 11 and for connection to the exhaust system on the vehicle. For this purpose, the tube intermediate piece has an inlet-side connecting flange 40A and an outlet-side connecting flange 40B, which are each fastened to the exhaust-gas guide with suitable connecting points. This variant is also particularly suitable for retrofitting.

It is essential that two fluid outlets 11A and 11B supplied together with fluid via a supply line 12 are provided in a single mixer disk 13 in the form of a fluid of slit-shaped recesses in the surface of the leeward surface 13A.

Claims

1. exhaust system (4) for an internal combustion engine (3), comprising

an exhaust gas inlet (5),

- An exhaust system (6) and

an exhaust gas outlet (7),

such that exhaust gas arising in the internal combustion engine (3) is introduced into the exhaust system (4) via the exhaust gas inlet (5), the exhaust gas duct (6) passes in the main flow direction (B) and out of the exhaust gas duct (6) via the exhaust gas outlet (6) ) exit,

wherein within the exhaust gas guide (6) at least one fluid outlet (1 1) for introducing a fluid, in particular a reducing fluid, is present,

characterized,

in that at least one mixer disk (13) for generating a leading edge vortex system (14) is present within the exhaust gas guide (6),

that the at least one fluid outlet (1 1) is arranged leeward to the at least one mixer disk (1 3), and

the at least one fluid outlet (11) is positioned relative to the mixer disk (13) such that the fluid exiting the mixer disk (13) flows into the leading edge vortex system (14) produced by the mixer disk (13) for mixing with the exhaust gas guide in the main flow direction (B) flowing through the exhaust gas occurs.

2. Exhaust system (4) according to claim 1,

characterized,

in that the at least one mixer disk (13)

- Is arranged at an acute angle (a) to the main flow direction (B) and / or

- Is positioned in such a manner in the exhaust gas guide (6) that the leading edge vortex system (14) produced by it in the exhaust is directed from an inner wall region of the exhaust gas guide (6) to the cross-sectional center (M) of the exhaust gas guide (6).

3. exhaust system (4) according to one of the preceding claims,

characterized,

in that the opening of the fluid outlet (11) is positioned in the generated front edge vortex system (14) and / or that the outlet opening of the fluid outlet (11) is positioned transversely to the main flow direction (B) at the level of the mixer disk (13).

4. exhaust system (4) according to one of the preceding claims,

characterized,

the mixer disk (13) has at least one of the following features:

- she is a plane disc;

it has a circular, elliptical, oval, polygonal, in particular triangular or diamond-shaped, contour;

it is formed, at least with respect to its edge course, symmetrically to the main flow direction (B),

- It is designed asymmetrically;

it comprises a three-dimensional deformation, in particular in the form of a curvature or angling in its surface;

- It is adjustable by means of an adjusting device relative to the exhaust gas guide (6), in particular displaceable and / or rotatable and / or tiltable.

5. Exhaust system (4) according to one of the preceding claims,

characterized,

the mixer disk (13) has an integrated fluid guide (12), wherein the mixer disk (13) is in particular double-walled with two mixer disk walls (13A, 13B) and at least partially the integrated fluid guide (12) in an intermediate space (15) between the two Mixer disk walls (13A, 13B).

6. exhaust system (4) according to one of the preceding claims,

characterized,

in that the exhaust system (4) comprises an exhaust manifold (8), and in that the at least one mixer disk (13) is arranged in the region of the exhaust manifold (8), in particular such that the mixer disk (13) in the main flow direction (B) leads to an internal curvature (B). 29) of the exhaust manifold (8) is inclined

7. exhaust system (4) according to one of the preceding claims,

characterized,

the fluid outlet (11) has at least one of the following features:

- The fluid outlet (11) is formed such that the main exit direction (C) of the fluid is at an angle of 0 ° to 90 ° to the main flow direction (B);

- The fluid outlet (11) is formed such that the outlet direction (C) of the fluid is at least partially directed directly to the at least one mixer disc (13);

- The fluid outlet (11) is formed such that the outlet direction (C) of the fluid is directed exclusively in the direction of the mixer disc (13) away;

- The fluid outlet (11) is a nozzle, in particular a multi-phase nozzle

8. exhaust system (4) according to one of the preceding claims,

characterized,

in that at least one mixer disk (13) is assigned a plurality of fluid outlets (11), in particular only two, wherein it is preferred if one of each of the two fluid outlets (11) in each case corresponds to one of the two front edge vortices (14A, 14B) produced by the mixer disk (13) ) assigned.

9. exhaust system (4) according to one of the preceding claims,

characterized ,

that, in particular exclusively, two mixer disks (1 3) are present, wherein the, in particular exclusively, two mixer disks (13) preferably have at least one of the following features:

- They are arranged parallel to each other;

- They are at an angle (ß) tilted to each other;

- They are arranged transversely to the main flow direction (B) at the same height;

- They are arranged in the main flow direction (B) at least partially offset one behind the other;

- Each mixer disk (13) is in each case at least one fluid outlet (1 1), in particular an outlet, assigned;

- They are identical in size and shape.

10. exhaust system (4) according to one of the preceding claims,

characterized ,

in that the at least one mixer disk (13) is arranged via a fastening device within the exhaust gas guide (6), wherein the fastening device has at least one of the following features:

- It comprises a by a wall of the exhaust guide (6) guided strut (16), wherein the at least one mixer disk (1 3) with the strut (16) is connected;

- It comprises at least one support element which is designed to bear against an inner wall of the exhaust gas guide (6), and a holding element, via which the at least one mixer disc (13) is connected to the at least one support element;

- It comprises a bearing sleeve (18), in the inner region of the mixer disc (13) is mounted and connected via a holding element (1 7) with the bearing sleeve (18);

- It comprises a flange (21) having a through hole (38), wherein the at least one mixer disk (1 3) is positioned at the level of the passage opening (38) and via a holding element (1 7) with the flange plate (21) is connected;

- The fastening device is connected via a welding, clamping and / or positive connection substantially stationary with the exhaust gas guide (6);

1 1. Flange plate (21) or bearing sleeve (18) with at least one mixer disk (13) for use in an exhaust system (4) according to the preceding claims.

12. Exhaust manifold with at least one mixer disk for an exhaust system according to one of claims 1 to 10.

1 3. Vehicle (1), in particular self-driving vehicle (1), with

an internal combustion engine (3),

- a chassis,

an exhaust system (4) connected to the internal combustion engine (3),

- A fluid tank (26) for a reducing agent, and

- One with the fluid tank (26) connected and in the interior of the exhaust system (4) opening fluid outlet (1 1)

characterized ,

in that it has an exhaust system (4) according to one of claims 1 to 10 with at least one mixer disk (13).

14. A method for operating an exhaust system (4), in particular according to one of claims 1 to 10, of an internal combustion engine (3), in particular of a self-propelled vehicle (1), comprising the steps:

a) driving (33) of an internal combustion engine (3) by burning a fuel, in particular for driving a crankshaft;

b) collecting (34) and guiding the exhaust gas formed in step a) in an exhaust system (4); c) generating (35) a substantially static leading edge vortex system (14) with at least one mixer disc (13);

d) introducing (36) a fluid into the leading edge eddy system (14);

e) mixing (37) the fluid with the exhaust gas in the leading edge vortex system (14).

15. The method according to claim 14,

characterized,

that it has at least one of the following features:

- The generation (35) of the leading edge vortex system (14) is such that the leading edge vortex (14A, 14B) from the direction of the inner wall of the exhaust guide (6) coming to the cross-sectional center (M) of the exhaust gas guide (6) is directed towards;

- An adjustment of the relative position of the at least one mixer disc (13) takes place relative to an inner wall of the exhaust system (4);

- The generation (33) of the leading edge vortex system (14) takes place in an exhaust manifold (8).