Mixing section for exhaust system of internal combustion engine

Abstract

The invention relates to a mixing section for an exhaust system of an internal combustion engine, comprising a mixing section housing and a mixing body arranged in the mixing section housing and extending in the direction of a longitudinal axis of the mixing body, the mixing body has a tubular first mixing body part extending in the direction of the longitudinal axis of the mixing body and a tubular second mixing body part extending in the direction of the longitudinal axis of the mixing body on the outer side of the first mixing body part facing the second flow volume, a mixing body is radially supported in a first radial support region by means of a plurality of first radial support means relative to a mixing section housing and in a second radial support region arranged at a distance from the first radial support region in the direction of the longitudinal axis of the mixing body by means of a plurality of second radial support means relative to the mixing section housing . The first mixing body part is radially supported on the mixing section housing by means of a first radial support mechanism, and the second mixing body part is radially supported on the mixing section housing by means of a second radial support mechanism.

Description

Technical Field

[0001] This invention relates to a mixing section for an exhaust system of an internal combustion engine, the mixing section comprising a mixing section housing through which exhaust gas flows in the main exhaust flow direction, and a tubular mixing body extending along the longitudinal axis of the mixing body disposed within the mixing section housing. The mixing body radially defines a first flow volume through which exhaust gas flows outward and a second flow volume radially inward. The mixing body has a tubular first mixing body component extending along the longitudinal axis of the mixing body and at least one tubular second mixing body component extending along the longitudinal axis of the mixing body on the outer side of the first mixing body component facing the second flow volume, wherein the second mixing body component is radially supported on the first mixing body component in a plurality of mixing body component support regions. Background Technology

[0002] Such a mixing section for exhaust equipment is known from the later-published German patent application 102024119108.2. Because in such a mixing section, the mixture on its outer and inner sides, which is circulated by exhaust gas, may be heated more strongly than the mixing section shell on its outer side, which is usually surrounded by ambient air, different thermally induced expansions may occur on one side of the mixing section shell and on the other side of the mixture during operation. Summary of the Invention

[0003] The objective of this invention is to provide a mixing section for an exhaust system of an internal combustion engine that ensures effective mixing of exhaust gas and reactants injected into the exhaust gas while simultaneously compensating for different thermally induced expansions of the mixing section components.

[0004] According to the present invention, this task is solved by a mixing section of an exhaust system for an internal combustion engine, the mixing section comprising:

[0005] -A mixing section shell that allows flow through the exhaust along the main exhaust flow direction.

[0006] - A tubular mixer extending along the longitudinal axis of the mixer is disposed in the mixing section housing, wherein the mixer radially defines a first flow volume through which exhaust gas can pass out radially outward and a second flow volume through which exhaust gas can pass out radially inward, wherein the mixer has a tubular first mixer component extending along the longitudinal axis of the mixer and at least one tubular second mixer component extending along the longitudinal axis of the mixer on the outer side of the first mixer component facing the second flow volume, wherein the second mixer component is radially supported on the first mixer component in a plurality of mixer component support regions.

[0007] The hybrid section according to the invention is characterized in that the hybrid body is radially supported relative to the hybrid section housing in a first radial support region by means of a plurality of first radial support mechanisms, and is radially supported relative to the hybrid section housing in a second radial support region provided at a distance from the first radial support region along the longitudinal axis of the hybrid body by means of a plurality of second radial support mechanisms, and a first hybrid body component is radially supported on the hybrid section housing by means of the first radial support mechanisms, and a second hybrid body component is radially supported on the hybrid section housing by means of the second radial support mechanisms.

[0008] In the hybrid section according to the invention, the support functions to be realized in two radially spaced support regions are distributed to a first hybrid component further radially inwardly disposed in the hybrid body and a second hybrid component surrounding the first hybrid component on its outer side. This allows the support functions to be realized in different radial support regions to be distributed in an optimized manner throughout the hybrid body, which should partly allow relative mobility but partly ensure defined fixed positioning. Simultaneously, the second hybrid component, with exhaust circulation on its inner and outer sides, functions as a heat transferor, receiving heat from the exhaust and transferring it to the first hybrid component through contact with it in the region of the hybrid component's support area. Because the two hybrid components are respectively circulated with exhaust on their outer and inner sides, the hybrid components have substantially the same temperature during operation, thus preventing substantially different thermally induced dimensional changes in the hybrid components, even considering that the two hybrid components may be constructed of the same material, especially metallic materials.

[0009] To ensure the positioning of the hybrid component relative to the definition of the hybrid section shell, while avoiding stress induced by different thermal expansion, it is proposed that a first hybrid component be fixedly held on the hybrid section shell for movement along the longitudinal axis of the hybrid component and / or in the circumferential direction around the longitudinal axis of the hybrid component by means of a first radial support mechanism, and a second hybrid component be movably radially supported on the hybrid section shell along the longitudinal axis of the hybrid component and / or in the circumferential direction around the longitudinal axis of the hybrid component by means of a second radial support mechanism.

[0010] The support function can be further defined as follows: a plurality of first radial support mechanisms are arranged at circumferential distances from each other in the circumferential direction surrounding the longitudinal axis of the hybrid body, and / or a plurality of second radial support mechanisms are arranged at circumferential distances from each other in the circumferential direction surrounding the longitudinal axis of the hybrid body.

[0011] The structural integration of the support function to be realized in the second radial support region into the components of the hybrid section can thus be achieved, i.e., at least a portion of the second radial support mechanism, preferably all of the second radial support mechanism, has a support protrusion forming part of the second hybrid component pointing in the direction away from the first hybrid component, or / and a support protrusion forming part of the hybrid section housing pointing in the direction towards the second hybrid component. This avoids the need for additional components to realize these support functions.

[0012] By providing a radial support mechanism as, for example, a protruding part of a second hybrid component or a hybrid segment housing, i.e., a convex protrusion pointing toward the corresponding other component, radial elasticity exists in the region of such a part, which can also compensate for the different thermally induced radial expansion of the hybrid segment housing on one hand and the hybrid on the other.

[0013] To ensure the relative mobility of the mixture with respect to the mixing section housing, the supporting protrusions of the second mixture component can be configured such that the supporting protrusions of the second mixture component are movably supported on the inner surface of the mixing section housing along the longitudinal axis of the mixture and / or along the circumferential direction around the longitudinal axis of the mixture, and / or the supporting protrusions of the mixing section housing are movably supported on the outer surface of the second mixture component along the longitudinal axis of the mixture and / or along the circumferential direction around the longitudinal axis of the mixture. If such protrusions pointing towards the other component are provided on both components, i.e., in this case on the mixing section housing and the second mixture component, these protrusions can be paired with each other, so that the protrusions of the second mixture component are radially supported on the protrusions of the mixing section housing respectively provided to these protrusions.

[0014] In order to retain the hybrid body axially and / or circumferentially in the first radial support region, at least a portion of the first radial support mechanism, preferably all of the first radial support mechanism, may have support elements fixed on the hybrid section housing and the first hybrid body components, preferably by material locking, such as fusion welding or brazing.

[0015] Alternatively or additionally, in order to obtain a design comprising as few components as possible, at least a portion of the first radial support mechanism, preferably all of the first radial support mechanism, may have a support protrusion forming part of the first hybrid component pointing toward the hybrid segment housing and preferably fixed to the hybrid segment housing by material locking, such as fusion welding or brazing, or / and a support protrusion forming part of the hybrid segment housing pointing toward the first hybrid component and preferably fixed to the first hybrid component by material locking, such as fusion welding or brazing.

[0016] In order to ensure the defined positioning of the mixture in the mixing section, especially in the upstream region of the mixture (where the reactant is usually also sprayed), it is proposed that a first radial support region is preferably located upstream of the second mixture component in the upstream end region of the mixture, or / and a second radial support region is located in the downstream end region of the mixture.

[0017] For the positioning of the first hybrid component radially inward with respect to the definition of the hybrid section housing, at least a portion of the second radial support mechanism, preferably all of the second radial support mechanism, may axially overlap with a portion of the support area of ​​the hybrid component.

[0018] In order to provide a support area for the hybrid component, the second hybrid component may have a plurality of first protruding molded portions arranged adjacent to each other in a circumferential direction around the longitudinal axis of the hybrid component and pointing toward the first hybrid component, wherein at least one first protruding molded portion, preferably each first protruding molded portion, forms a support area for the hybrid component.

[0019] In order to obtain a substantially regular convex pattern and thereby obtain substantially uniform heat transfer between the two mixtures, it is proposed that the first convex portion be arranged in a plurality of rows of the first convex portion arranged successively along the circumferential direction around the longitudinal axis of the mixture, preferably extending substantially along the longitudinal axis of the mixture, or / and the first convex portion be arranged in a plurality of rings of the first convex portion arranged successively along the longitudinal axis of the mixture, preferably extending substantially along the circumferential direction around the longitudinal axis of the mixture.

[0020] For particularly effective heat transfer between the second hybrid component and the first hybrid component, it is proposed that at least a portion of the first protruding part, preferably each of the first protruding parts, be configured as a closed protruding part, or / and at least a portion of the first protruding part, preferably each of the first protruding parts, be configured with a protruding circumferential wall and a protruding bottom that abuts against the first hybrid component, preferably substantially flat or curved substantially to match the curvature of the first hybrid component, or / and at least a portion of the first protruding part, preferably each of the first protruding parts, be circularly configured.

[0021] Further enhanced thermal interaction with the exhaust can be achieved by having a plurality of second protruding shaped portions, which are arranged adjacent to each other along the longitudinal axis of the mixture and in the circumferential direction surrounding the longitudinal axis of the mixture, pointing away from the first mixture component.

[0022] When further configured such that at least one opening is provided in the second composite component adjacent to at least a portion of the second protruding forming portion, preferably each of the second protruding forming portions, preferably wherein in each pair consisting of the second protruding forming portion and the opening partially overlap each other, there is a possibility that exhaust gas flowing into the gap between the two composite components flows out again from the gap and for this purpose, hotter exhaust gas enters the gap and transfers heat to the composite component.

[0023] The outflow and inflow of exhaust gas from or into the gap formed between the two hybrid components can be further aided by the fact that, in a portion of each pair consisting of a second protruding part and an opening arranged with each other, the opening is provided on a first side, preferably a first axial side, of the arranged second protruding part, and in another portion of each pair consisting of a second protruding part and an opening arranged with each other, the opening is provided on a second side, preferably a second axial side, of the arranged second protruding part that is substantially opposite to the first side.

[0024] The associated second protruding part can also provide a regular protruding pattern that assists in uniform heat transfer. That is, the second protruding part is arranged in rows of multiple second protruding parts arranged successively along the circumferential direction around the longitudinal axis of the mixture, preferably extending substantially along the longitudinal axis of the mixture, or / and the second protruding part is arranged in rings of multiple second protruding parts arranged successively along the longitudinal axis of the mixture, preferably extending substantially along the circumferential direction around the longitudinal axis of the mixture.

[0025] To introduce the reactant, a reactant release arrangement can be provided upstream of the mixture along the main exhaust flow direction. This reactant release arrangement ensures that the reactant is released substantially only into the first flow volume. Because virtually no reactant reaches the gap formed between the two mixture components, there is no risk of reactant deposition in this gap.

[0026] Stable connection for auxiliary heat transfer of the two hybrid components can be achieved, for example, by fixing the second hybrid component to the first hybrid component preferably by material locking, such as fusion welding or brazing, in at least a portion, preferably all, of the support area of ​​the hybrid component. Because the two hybrid components have substantially the same temperature during operation and are preferably constructed of the same material or of a material with substantially the same coefficient of thermal expansion, there is no risk of stress arising from fixing the two hybrid components to each other.

[0027] The present invention also relates to an exhaust system for an internal combustion engine, the exhaust system comprising a mixing section constructed according to the present invention and including an exhaust treatment unit, preferably an SCR catalyst, downstream of the mixing section. Attached Figure Description

[0028] The invention will now be described in detail with reference to the accompanying drawings. Wherein:

[0029] Figure 1 A schematic diagram of an exhaust system for an internal combustion engine, including a mixing section, is shown.

[0030] Figure 2 It is shown in its diagram a). Figure 1 exhaust equipment along Figure 1 A cross-sectional view cut by lines IIa)-IIa), and shown in its illustration b). Figure 1 exhaust equipment along Figure 1 A cross-sectional view cut by line IIb)-IIb);

[0031] Figure 3 A perspective view of a hybrid constructed using two tubular hybrid components is shown.

[0032] Figure 4 A detailed longitudinal sectional view of the mixture is shown;

[0033] Figure 5 A cross-sectional view of the mixture is shown in the section corresponding to section IIb)-IIb).

[0034] Figure 6 Different design types of radial support mechanisms are shown in their diagrams a) to d). Detailed Implementation

[0035] exist Figure 1 The diagram illustrates, in principle, a section of an exhaust system for an internal combustion engine, generally indicated by 10. The exhaust system 10 has a mixing section, generally indicated by 12, and an exhaust treatment unit 14 downstream of the mixing section 12. In the example shown, the exhaust treatment unit 14 has an SCR catalytic converter.

[0036] The mixing section 12 has a mixing section housing 16, in which a substantially tubular mixture 18 extending longitudinally along the longitudinal axis L of the mixture is disposed. Exhaust gas discharged from an internal combustion engine, especially a diesel internal combustion engine, flows into the mixing section housing 16 or toward the mixture 18 in a main exhaust flow direction H that is substantially corresponding to the longitudinal axis L of the mixture.

[0037] The mixture 18 has a tubular first mixture component 20 comprising a closed circumferential wall 22, for example, substantially cylindrical and having a circular cross-section. Through the first mixture 20 or its circumferential wall 22, the internal volume of the mixing section housing 16 is divided in the axially extending region of the mixture 18 into a first flow volume 24 and a second flow volume 26 formed within and surrounded by, or defined radially outward by, the circumferential wall 22, of the first mixture component 20 or the circumferential wall 22. The second flow volume is formed between the mixing section housing 16 and the first mixture component 20 or defined radially inward by the first mixture component.

[0038] The exhaust device 10 or mixing section 12 also has a reactant release arrangement 28, generally referred to as an injector, which sprays reactant R, for example, in the form of a spray, i.e., in the form of fine droplets, into the exhaust gas A flowing in the mixing section housing 16. The reactant release arrangement 28 is configured such that it releases reactant R into the first flow volume 24 and thus into the portion T1 of exhaust gas A flowing in the first flow volume 24. Therefore, substantially no reactant R is injected into the second flow volume 26 and the second portion T2 of exhaust gas A flowing in the second flow volume 26. The second flow volume 26 is therefore only traversed by exhaust gas A, i.e., the second portion T2, and, as explained in detail below, is primarily used to transfer the heat transported in exhaust gas A to the mixture 18 or the first mixture component 20. By enhancing the heating of the first mixing component 20, the reactant R that comes into contact with the inner side 30 of the circumferential wall 22 is evaporated, thereby achieving improved mixing of the reactant R and the exhaust gas A, without the need for system areas, such as mixers or the like, that would result in increased flow resistance.

[0039] A tubular second mixing component 34 is disposed on the outer side 32 of the circumferential wall 22 of the first mixing component 20 facing the second flow volume 26. This second mixing component preferably completely surrounds the first mixing component 20 in its entire axial extension region and in the circumferential direction and substantially functions as a heat exchanger, through which the heat transported in the second part flow T2 of the exhaust A can be enhancedly input into the mixture 18.

[0040] The following are the main references Figure 1 , 2 Before detailing the retention of the mixture 18 within the mixing section housing 16 according to the principles of the invention in sections 5 and 6, first refer to... Figure 3 and 4The structure of the hybrid 18 is known in principle from the later published German patent application DE102024119108.2, the hybrid comprising a tubular first hybrid component 20 and a circumferential wall 22 that closes the first hybrid component in the circumferential direction, and a tubular second hybrid component 34 surrounding the first hybrid component 20 or its circumferential wall 22.

[0041] Similarly, the second hybrid component 34, configured as a sheet metal part, has a plurality of first protruding portions 36, typically cup-shaped, distributed along the axial length of the second hybrid component 34 and in a circumferential direction surrounding the longitudinal axis L of the hybrid component. These cup-shaped first protruding portions 36 are formed on the second hybrid component 34 such that they extend from a reference level of the second hybrid component 34 at a substantially constant distance relative to the outer side 32 of the first hybrid component 20 and abut against that outer side. Each first protruding portion 36 abutting against the outer side 32 of the first hybrid component 20 forms a hybrid component support region 37, with the second hybrid component 34 radially supported on the first hybrid component 20 by this hybrid component support region.

[0042] The protruding portion 36 comprises a protruding circumferential wall 38 and a protruding bottom 40 abutting against the outer side 32 of the first hybrid component 20, and has a circular structure in a top view. The protruding bottom 40 is substantially planar or adapted to the curvature of the outer side 32 of the first hybrid component 20, thereby creating a planar contact between the second hybrid component 34 and the first hybrid component 20 in the region of the protruding bottom 40. Preferably, in all regions of the first protruding portion 36, a material-locking bond is created between the two hybrid components 20, 34, for example by fusion welding or brazing, in order to generate good thermal contact.

[0043] exist Figure 3 As can be seen, multiple rows of first protruding formed portions 36 are formed on the second composite component 34, extending substantially along the longitudinal axis L of the composite. In the rows of first protruding formed portions 36 that are directly adjacent to each other in the circumferential direction, the first protruding formed portions 36 are staggered from each other along the longitudinal axis L of the composite, so that the first protruding formed portions 36 of another row are positioned between two first protruding formed portions 36 in one row along the longitudinal axis L of the composite. For uniform heat transfer contact, it is preferable that the first protruding formed portions 36 in the rows of first protruding formed portions 36 are arranged at substantially uniform distances from each other along the longitudinal axis L of the composite.

[0044] Similarly, a ring of first protruding shaped portions 36 extending in the circumferential direction around the longitudinal axis L of the mixture is formed on the second composite component 34. In these rings of the first protruding shaped portions 36, the first protruding shaped portions 36 are also spaced substantially evenly from each other, and in the rings where the first protruding shaped portions 36 are directly adjacent to each other in the direction of the longitudinal axis L of the mixture, the first protruding shaped portions 36 are staggered from each other in the circumferential direction, thereby positioning the first protruding shaped portion of the other ring circumferentially between the two first protruding shaped portions 36 of one of the two rings.

[0045] The substantially uniform pattern of the first protruding forming portion 36 along the entire axial extension and circumference of the second hybrid component 34 creates a substantially uniform heat transfer contact between the two hybrid components 34, 20. The exhaust gas A flowing along the second hybrid component 34 in the second flow volume 26 of the second sub-flow T2 can thus circulate on the outer side 42 of the second hybrid component 34 away from the first hybrid component 20 and on the inner side 44 of the second hybrid component towards the first hybrid component 20, thereby transferring heat to the second hybrid component. The heat received in the second hybrid component 34 is transferred to the first hybrid component 20 through the contact between the two hybrid components 34, 20 in the region of the first protruding forming portion 36. Particularly advantageously, the arrangement of the plurality of first protruding forming portions 36 in the regions of the inner side 44 and outer side 42 of the second hybrid component 34 generates turbulence, which improves the thermal interaction between the exhaust gas A in the second sub-flow T2 and the second hybrid component 34.

[0046] To further improve thermal interaction and enhance heat input to the first hybrid component 20, the second hybrid component 20 has a plurality of second protruding portions 46. Each second protruding portion 46 is provided with an opening 48, thereby forming corresponding pairs of second protruding portions 46 and openings 48. The second protruding portions 46 are oriented radially outward about the longitudinal axis L of the hybrid, i.e., in a direction away from the first hybrid component 20, and are positioned about the respective provided openings 48 such that in each pair formed by the second protruding portions 46 and openings 48, the second protruding portions and openings overlap each other, i.e., the openings 48 extend into the region of the protruding portions 46. This results in Figure 4 As can be seen in the structure, each of these second protruding shaped portions 46 is formed in the form of a section of a spherical crown or similar shaped crown and opens toward the respective provided openings 48.

[0047] exist Figure 3 and 4Furthermore, it can be seen that in each pair of second protruding portions 46 and openings 48, the second protruding portions and openings are axially arranged sequentially along the longitudinal axis L of the mixture. The second protruding portions 46 or openings 48, or pairs formed by the second protruding portions 46 and openings 48, are also arranged in rows extending substantially along the longitudinal axis L of the mixture. This arrangement also ensures that the second protruding portions 46 or openings 48, or pairs formed by the second protruding portions 46 and openings 48, are staggered from each other along the circumferential direction of the directly adjacent rows of the second protruding portions 46, along the longitudinal axis L of the mixture. Similarly, the second protruding portions 46 or their associated openings 48, or pairs formed by the second protruding portions 46 and openings 48, form corresponding rings extending in the circumferential direction. In these rings, the second protruding portions 46, positioned at a uniform distance from each other not only in the circumferential direction but also along the longitudinal axis L of the mixture, are also staggered from each other. In particular, a structure is provided in which the second protruding forming portion 46 or opening 48 is integrated into the space between the two first protruding forming portions 36 not only in the axial direction but also in the circumferential direction, thereby creating an alternating sequence of first protruding forming portions 36 and second protruding forming portions 46 including the respectively arranged openings 48 not only in the axial direction but also in the circumferential direction, and thus the rows and rings of the first protruding forming portions 36 correspond to the rows or rings of the second protruding forming portions 46.

[0048] exist Figure 3 Furthermore, it can be seen that in the two rows of the second protruding forming portion 46 that are directly adjacent to each other in the circumferential direction, the openings 48 are located on different sides of the second protruding forming portion 46. In one row of the two rows of the second protruding forming portion 46 that are directly adjacent to each other in the circumferential direction, the corresponding opening 48 is located on the first side of the second protruding forming portion 46, in particular on the first axial side, while in the other row of the two rows of the second protruding forming portion 46 that are directly adjacent to each other in the circumferential direction, the corresponding opening 48 is located on the other side of the second protruding forming portion 46, that is, in particular on the other axial side. Therefore, an alternating pattern of axial opening directions of the second protruding forming portion 46 is generated not only in the circumferential direction but also in the axial direction in the directly adjacent rings of the second protruding forming portion, thereby allowing the auxiliary exhaust gas A to flow into the gap 50 formed between the two hybrid components 20 and 34 and to flow out from the gap 50. The second protruding part 46 thus not only helps to enhance turbulence in the near-surface region of the second hybrid component 34, but also assists in the exhaust exchange in the gap 50, thereby improving heat transfer between the two hybrid components 34, 20 and also improving the thermal contact between the first hybrid component 20 and the second partial flow T2 flowing in the second flow volume 26.

[0049] Various variations can be achieved in the configuration of the mixture 18 shown in the figure. For example, the rows of first or second protruding parts 36, 46 can have an orientation deviating from the parallel orientation relative to the longitudinal axis L of the mixture, i.e., having a circumferential extension component, thereby creating a threaded pattern of rows of first or second protruding parts 36, 46 adjacent to each other circumferentially. In another design, the second mixture component 34 may be disposed on the inner side 30 of the first mixture component 20, in which case the reactant release arrangement 28 can be configured to introduce the reactant R into the second flow volume 26, so that the first flow volume 24 is essentially only traversed by the exhaust gas A. It is also possible that multiple such second mixture components 34 are arranged successively, for example, at an axial distance from each other, along the longitudinal axis L of the mixture, wherein, for example, the rows of first or second protruding parts 36, 46 in the axially successive second mixture components 34 can be staggered circumferentially.

[0050] The number of first protruding portions 36 or second protruding portions 46 can also be varied. Thus, for example, along the axial direction and / or along the circumferential direction, two second protruding portions 46 including respectively disposed openings 48 may be positioned between two respective first protruding portions 36, or two or more first protruding portions 36 may be disposed between two second protruding portions 46 including disposed openings 48.

[0051] In another alternative design, at least a portion of the second protruding portion 46 may be provided with two openings 48 on opposite sides of the respective second protruding portion 46. Each of these openings 48 may then extend into or overlap with the provided second protruding portion 46, for example, axially, thereby forming a bridge portion between the two openings 48 provided thereto, pointing in a direction away from the first composite component 20.

[0052] Finally, it can be configured such that at least in a portion of the region of the mixture 18, or at least a portion of the first protruding forming portion 36 and / or a portion of the second protruding forming portion 46, together with the respective provided openings 48, are not arranged in the symmetrical or ordered structure shown in the figure, but rather that these protruding forming portions 36, 46 are arranged in a statistical or disordered distribution, including uneven mutual distances in the circumferential and axial directions and without any defined orientation of each other in the circumferential and axial directions.

[0053] Next, the retention of the mixture 18 in the mixing section housing 16 according to the principle of the present invention will be described.

[0054] The mixture 18 is held on the mixing section housing 16 within two radially supported regions 50 and 52, spaced apart from each other along the longitudinal axis L of the mixture. The first radially supported region 50 is located on the upstream end region 54 of the mixture 18 and, as explained below, is used to also axially fix the mixture 18 to the mixing section housing 16. The second radially supported region 52 is located on the downstream end region 56 of the mixture 18 and, as explained below, is used to radially support the mixture 18 to the mixing section housing 16, but in principle allows relative movement between the mixture 18 and the mixing section housing 16.

[0055] The first radial support region 50 has a plurality of first radial support mechanisms 58, which are arranged, for example, in the same axial region about the longitudinal axis L of the mixture, and can be evenly spaced from each other in the circumferential direction. Figure 2 In the design example shown in a), three such first radial support mechanisms 58 are provided, which may have an angular distance of approximately 120° from each other, for example.

[0056] Through each of the first radial support mechanisms 58, in the first radial support region 50, the first hybrid component 20 is radially supported relative to the hybrid section housing 16 or fixed on the hybrid section housing 16 in the direction of the hybrid longitudinal axis L and also in the circumferential direction around the hybrid longitudinal axis L. For this purpose, the first radial support mechanism 58 can be provided or fixed to the first hybrid component 20 in the direction of the hybrid longitudinal axis L. Figure 3 As can be seen in the section 59 extending axially beyond the second hybrid component 34 in the upstream end region 54 of the hybrid 18. The first radial support region 50 or its first radial support mechanism 58 is therefore upstream of the second hybrid component 34 with respect to the main exhaust flow direction H.

[0057] As in Figure 6 As illustrated in a), for example, the first radial support mechanism can be provided as a separately constructed, for example, bolt-like support element 60, which can be fixed to the first hybrid component 20 in its radially inner region by material locking, i.e., by fusion welding or brazing, in the region of the first hybrid component segment 59, and can be fixed to the hybrid segment housing 16 in its radially outer region by material locking, i.e., by fusion welding or brazing.

[0058] Therefore, by means of support elements, the positioning of the mixture 18 in the mixing section housing 16 is ensured in the upstream end region 54, in the direction defined along the longitudinal axis L of the mixture, in the circumferential direction surrounding the longitudinal axis L of the mixture, and in the radial direction. This defined positioning of the mixture 18 in its upstream end region 54 is particularly advantageous because the reactant R is also injected into the mixing section 12 in this region, and the defined positioning of the mixture 18 ensures that substantially no reactant R reaches the second flow volume 26.

[0059] exist Figure 6 Alternative designs for this first radial support mechanism 58 are shown in 6b), 6c), and 6d).

[0060] Figure 6 (b) illustrates a design in which the radial support mechanism 58 is formed by a radially outward, i.e., toward the mixing section housing 16, support protrusion 62 on a segment 59 of the first hybrid component 20. The support protrusion 62, configured as a convex protrusion, is supported on the inside of the mixing section housing 16 in its top region and is fixed to the mixing section housing 16 in that region by material locking, such as fusion welding or brazing.

[0061] The support protrusion 62 may have a generally spherical design, but alternatively may have a can or cup-shaped design as previously described with respect to the first protrusion 36 of the second hybrid component 34.

[0062] exist Figure 6 In the design shown in c), the first radial support mechanism 58 is provided by a support protrusion 64 disposed on the mixing section housing 16 and pointing radially inward toward the first hybrid component 20 or the section 59 of the first hybrid component. These support protrusions may also have the shape described earlier with respect to the support protrusion 62 and are fixed to the first hybrid component 20 by material locking, preferably fusion welding or brazing, in their top or bottom regions.

[0063] Figure 6 d) illustrates a design in which such support protrusions 62, 64 are provided not only on the first hybrid component 20 but also on the hybrid section housing 16. These support protrusions are preferably arranged such that pairs of support protrusions 62, 64 are formed, such that the support protrusions 62 of the first hybrid component 20 abut against the respective provided support protrusions 64 of the hybrid section housing 16 in their top or bottom regions and are connected to these support protrusions by material locking, for example, fusion welding or brazing.

[0064] The design of the first radial support mechanism 58 as an integral part of the first hybrid component 20 or the hybrid segment housing avoids the need for additional components and provides the possibility of compensating for the different thermally induced radial expansion of the hybrid segment housing 16 or the first hybrid component 20 on the one hand, based on the radial elasticity of the hybrid segment housing 16 or the first hybrid component 20 on the other hand, in the area of ​​such support protrusions 62, 64.

[0065] In the second radial support region 52, the hybrid body 18 is radially supported about the hybrid segment housing 16 by a plurality of second radial support mechanisms 66 in the region of its downstream end region 56. The second radial support mechanisms 66 act between the second hybrid body component 34 and the hybrid segment housing 16 and can be as follows: Figure 2 As illustrated in b), the components are preferably arranged at a uniform distance from each other in the same axial region along the circumferential direction surrounding the longitudinal axis L of the mixture. Figure 2 In the design illustrated in b), there are three such second radial support mechanisms 66, which can have an angular distance of 120° from each other.

[0066] The second radial support mechanism 66 is disposed on the downstream end region 68 of the second hybrid component 34 and, for example, through the second hybrid component 34 in Figure 5 A radially outwardly oriented support protrusion 70, oriented toward the mixing section housing 16, is provided, as can be seen in the image. For example, such a support protrusion 70 can be provided between two successive first protrusions 36 in the circumferential direction of the second mixing component 34. To achieve this, for example, a second protrusion 46 including a disposed opening 48 can be provided between two associated first protrusions 36 in such a region of the second mixing component 34. Instead of such a second protrusion 46 or opening 48, an outwardly oriented support protrusion 70 can be formed in such a location, as shown in... Figure 5 The shape shown in the image may be, for example, a crown or similar shape, or it may have a shape similar to the first protruding part 36.

[0067] The second radial support region 52 or its second radial support mechanism 66 is therefore substantially in the same axial region as a portion of the first protruding portion 36 disposed on the second hybrid component 34 and forming the hybrid component support region 37, such that at least a portion of the second radial support region 66, preferably all of the second radial support regions 66, axially overlaps with a portion of the first protruding portion 36 or the hybrid component support region 37 in the axial direction or in the direction of the main exhaust flow H. For example, the second radial support region 66 may be disposed in the same axial region or axially overlap with the first protruding portion 36 of the ring of the first protruding portion positioned furthest downstream with respect to the main exhaust flow direction H.

[0068] Using these support protrusions 70, the hybrid 18 is radially supported on the hybrid section housing 16 at its downstream end region 56; however, the hybrid section housing 16 is not fixed in principle. If there is different thermal expansion between the hybrid 18 and the hybrid section housing 16, the hybrid 18 can move along the inner surface of the hybrid section housing 16, especially in the axial direction, with the support protrusions 70, thereby avoiding stress caused by different thermal expansion. Meanwhile, the support protrusions 70 of the second radial support mechanism 66, which is an integrated component of the second hybrid component 34, can be formed radially, so that different radial dimensional variations can be compensated for by the deformation of the second hybrid component 34 in the region of the support protrusions 70.

[0069] It should be noted that, alternatively, the second support mechanism 66 may also have... Figure 6 The structures shown in c) and d) indicate that the second support mechanism 66 may alternatively be provided as a radially inwardly pointing support protrusion formed on the mixing section housing 16 and supported on the second mixing component 34. The combined effect of the radially supported support protrusions of the mixing section housing 16 and the second mixing component 34 also... Figure 6 It is possible in the sense shown in d), however, without such support protrusions being fixed to each other.

[0070] The mixer 18 is supported on the mixing section housing 16 in its downstream end region 56. It is possible, particularly in the region of the mixer 18, that the first mixer component 20, through which the mixture of reactant R or reactant R and exhaust gas A flows on its inner side, is designed with a substantially smooth, unstructured surface, where reactant R injected into the first flow volume 24 also flows. This avoids cavities that would cause deposits of reactant R.

[0071] Finally, it should be noted that the design and positioning of the first and second radial support mechanisms 58, 66 can vary in various ways. For example, the second radial support mechanism 66 or the second radial support region 52 can be positioned further upstream, such that the mixture 18 can be supported on the mixing section housing 16 via the second radial support region 52 in its intermediate length region or additionally in its intermediate length region. Different radial support mechanisms 58, 66 can also be arranged in different numbers and staggered from each other in the circumferential direction. In the first radial support region 50, for example, an annular support element may be positioned in the mixing section housing 16 between the first mixture component 20 and the mixing section housing 16, wherein the support element may have multiple openings allowing exhaust gas to flow through into the second flow volume 26. The tab region defining these openings in the circumferential direction then forms the radial support mechanism in the sense of the present invention.

[0072] In principle, the arrangement of the first radial support region 50 and the second radial support region 52 with the two end regions 54 and 56 of the mixture 18 may also be reversed. That is, the mixture 18 may be radially supported and fixed to the mixing section housing 16 in its downstream end region 56 by the first radial support mechanism 58, while the second radial support mechanism 66, which acts between the second mixture component 34 and the mixing section housing 16, may be provided, for example, in the upstream end region 54 of the mixture 18, and the first radial support mechanism may then act between the axially extending section 72 of the first mixture component 20 and the mixing section housing 16.

[0073] Regardless of the location and design type of the different radial support mechanisms, these radial support mechanisms not only ensure compensation for different dimensional variations but also include tolerance compensation functions. Furthermore, especially when the radial support mechanisms are formed as protruding parts, they also serve to buffer oscillations in the radial direction and, through friction relative to other components, in the axial or circumferential directions. Simultaneously, these protruding parts act as centering aids when the hybrid body 18 is assembled into the hybrid section housing 16. Because during the operation of this hybrid section 12, the hybrid body 18 and the hybrid section housing 16 are in contact only through different radial support mechanisms 58, 66, heat outflow through the hybrid section housing 16 is also minimized.

Claims

1. A mixing section for an exhaust system of an internal combustion engine, the mixing section comprising: -A mixing section shell (16) through which exhaust (A) flows along the main exhaust flow direction (H). -A tubular mixture (18) extending along the longitudinal axis (L) of the mixture is disposed in the mixing section housing (16), wherein the mixture (18) radially defines a first flow volume (24) through which exhaust gas (A) can flow and radially defines a second flow volume (26) through which exhaust gas (A) can flow, wherein the mixture (18) has a tubular first mixture component (20) extending along the longitudinal axis (L) of the mixture and at least one tubular second mixture component (34) extending along the longitudinal axis (L) of the mixture on the outer side (32) of the first mixture component (20) facing the second flow volume (26), wherein the second mixture component (34) is radially supported on the first mixture component (20) in a plurality of mixture component support areas (37). The feature is that the hybrid body (18) is radially supported relative to the hybrid section housing (16) in a first radial support region (50) by means of a plurality of first radial support mechanisms (58), and is radially supported relative to the hybrid section housing (16) in a second radial support region (52) which is set at a distance from the first radial support region (50) along the longitudinal axis (L) of the hybrid body by means of a plurality of second radial support mechanisms (66). Furthermore, the first hybrid body component (20) is radially supported on the hybrid section housing (16) by means of the first radial support mechanisms (58), and the second hybrid body component (34) is radially supported on the hybrid section housing (16) by means of the second radial support mechanisms (66).

2. The hybrid section according to claim 1, characterized in that, The first hybrid component (20) is fixedly held on the hybrid section housing (16) for movement along the direction of the hybrid longitudinal axis (L) and / or along the circumferential direction around the hybrid longitudinal axis (L) by means of the first radial support mechanism (58), and the second hybrid component (34) is radially supported on the hybrid section housing (16) for movement along the direction of the hybrid longitudinal axis (L) and / or along the circumferential direction around the hybrid longitudinal axis (L) by means of the second radial support mechanism (66).

3. The hybrid segment according to claim 1 or 2, characterized in that, A plurality of first radial support mechanisms (58) are provided with a circumferential distance between each other in the circumferential direction surrounding the longitudinal axis (L) of the hybrid body, and / or a plurality of second radial support mechanisms (66) are provided with a circumferential distance between each other in the circumferential direction surrounding the longitudinal axis (L) of the hybrid body.

4. The mixing section according to any one of claims 1-3, characterized in that, At least a portion of the second radial support mechanism (66), preferably all of the second radial support mechanism (66), has a support protrusion (70) of the second hybrid component (34) pointing in the direction away from the first hybrid component (20) and / or a support protrusion of the hybrid segment housing (16) pointing in the direction toward the second hybrid component (34).

5. The mixing section according to claim 4, characterized in that, The support protrusion (70) of the second hybrid component (34) is movable along the direction of the longitudinal axis (L) of the hybrid and / or along the circumferential direction around the longitudinal axis (L) of the hybrid and / or the support protrusion of the hybrid component (16) is movable along the direction of the longitudinal axis (L) of the hybrid and / or along the circumferential direction around the longitudinal axis (L) of the hybrid and is supported on the outer surface of the second hybrid component (34).

6. The mixing section according to any one of claims 1-5, characterized in that, At least a portion of the first radial support mechanism (58), preferably all of the first radial support mechanism (58), has a support element (60) that is preferably fixed by material locking on the hybrid section housing (16) and the first hybrid component (20).

7. The hybrid segment according to any one of claims 1-6, characterized in that, At least a portion of the first radial support mechanism (58), preferably all of the first radial support mechanism (58), has a support protrusion (62) of the first hybrid component (20) pointing toward the hybrid segment housing (16) and preferably fixed to the hybrid segment housing (16) by material locking, or / and a support protrusion (64) of the hybrid segment housing (16) pointing toward the first hybrid component (20) and preferably fixed to the first hybrid component (20) by material locking.

8. The mixing section according to any one of claims 1-7, characterized in that, The first radial support region (50) is preferably located upstream of the second mixture component (34) in the upstream end region (54) of the mixture (18) with respect to the main exhaust flow direction (H), or / and the second radial support region (52) is located in the downstream end region (56) of the mixture (18).

9. The hybrid section according to any one of claims 1-8, characterized in that, At least a portion of the second radial support mechanism (66), preferably all of the second radial support mechanisms (66), axially overlaps with a portion of the hybrid component support region (37).

10. The hybrid segment according to any one of claims 1-9, characterized in that, The second hybrid component (34) has a plurality of first protruding molded portions (36) arranged adjacent to each other in the direction of the longitudinal axis (L) of the hybrid and in the circumferential direction surrounding the longitudinal axis (L) of the hybrid, pointing toward the first hybrid component (20), and at least one first protruding molded portion (36), preferably each first protruding molded portion (36), forms a hybrid component support region (37).

11. The hybrid section according to claim 10, characterized in that, The first protruding part (36) is arranged in a row of multiple first protruding parts (36) arranged successively along the circumferential direction surrounding the longitudinal axis (L) of the mixture, preferably extending substantially along the direction of the longitudinal axis (L) of the mixture, or / and the first protruding part (36) is arranged in a ring of multiple first protruding parts (36) arranged successively along the direction of the longitudinal axis (L) of the mixture, preferably extending substantially along the circumferential direction surrounding the longitudinal axis (L) of the mixture.

12. The hybrid segment according to claim 10 or 11, characterized in that, At least a portion of the first protruding part (36), preferably each of the first protruding parts (36) is configured as a closed protruding part, or / and at least a portion of the first protruding part (36), preferably each of the first protruding parts (36) is configured with a shaped circumferential wall (38) and a protruding bottom (40) that is attached to the first hybrid part (26), preferably substantially planar or curved substantially to match the curvature of the first hybrid part (20), or / and at least a portion of the first protruding part (36), preferably each of the first protruding parts (36) is circularly configured.

13. The hybrid segment according to any one of claims 1-12, characterized in that, The second hybrid component has a plurality of second protruding forming portions (46) that are arranged adjacent to each other along the longitudinal axis (L) of the hybrid and in the circumferential direction surrounding the longitudinal axis (L) of the hybrid and pointing away from the first hybrid component (20).

14. The hybrid section according to claim 13, characterized in that, Adjacent to at least a portion of the second protruding forming portion (46), preferably each of the second protruding forming portions (46), at least one opening (48) is provided in the second hybrid component (34), preferably wherein, in each pair consisting of the second protruding forming portion (46) and the opening (48) arranged with each other, the second protruding forming portion (46) and the opening (48) partially overlap each other.

15. The hybrid section according to claim 14, characterized in that, In one pair consisting of a second protruding part (46) and an opening (48) arranged with each other, the opening (48) is provided on a first side, preferably a first axial side, of the arranged second protruding part (46), and in another pair consisting of a second protruding part (46) and an opening (48) arranged with each other, the opening (48) is provided on a second side, preferably a second axial side, of the arranged second protruding part (46) that is substantially opposite to the first side.

16. The hybrid segment according to any one of claims 13-15, characterized in that, The second protruding part (46) is arranged in a row of multiple protruding parts (46) arranged successively along the circumferential direction surrounding the longitudinal axis (L) of the mixture, preferably extending substantially along the direction of the longitudinal axis (L) of the mixture, or / and the second protruding part (46) is arranged in a ring of multiple protruding parts (46) arranged successively along the direction of the longitudinal axis (L) of the mixture, preferably extending substantially along the circumferential direction surrounding the longitudinal axis (L) of the mixture.

17. The hybrid segment according to any one of claims 1-16, characterized in that, A reactant release arrangement structure (28) is provided upstream of the mixture (18) along the main exhaust flow direction (H), the reactant release arrangement structure being used to release the reactant (R) essentially only into the first flow volume (24).

18. The hybrid segment according to any one of claims 1-17, characterized in that, The second hybrid component (34) is preferably fixed to the first hybrid component (20) by material locking in at least a portion of the hybrid component support area (37), preferably all of the hybrid component support areas (37).

19. An exhaust system for an internal combustion engine, the exhaust system comprising a mixing section (12) according to any one of claims 1-18 and comprising an exhaust treatment unit (14), preferably an SCR catalyst, downstream of the mixing section (12).

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