Exhaust-gas aftertreatment unit

Abstract

The invention relates to an exhaust-gas aftertreatment unit (1) at least comprising a casing (2), a supporting structure (5), and a honeycomb body (3) which is supported or secured on the supporting structure (5) by means of supporting pins (4), wherein the supporting structure (5) has at least one at least partly circumferential frame (6) which defines a base plane (8) and an outer circumferential plane (10), and the frame (6) has a plurality of tabs (7) which are formed transversely to the base plane (8), said plurality of tabs (7) having inner faces (9) between which the honeycomb body (3) is positioned.

Description

[0001] exhaust aftertreatment unit

[0002] The invention relates to an exhaust gas aftertreatment unit which is particularly suitable for exhaust gas aftertreatment of internal combustion engines.

[0003] The invention particularly relates to an exhaust aftertreatment unit comprising a casing (housing), a support structure, and a honeycomb body supported or secured to the support structure by support pins. An exhaust gas can flow through the honeycomb body, in particular such that the exhaust gas can be thermally and / or catalytically treated as it flows through. The support structure typically has an outer frame with which it is supported or secured to an inner side of the casing.

[0004] Exhaust gas flows through the exhaust aftertreatment unit. The honeycomb body can serve to warm the exhaust stream. The exhaust gas flows through the casing, encounters the support structure or penetrates it, and then flows through the honeycomb body. It is also possible for the exhaust gas to first flow through the honeycomb body and then the support structure. In this case, a changing and / or relatively high load can act on the support structure that holds or supports the honeycomb body. Therefore, a method must be created for securely holding the support structure in / on the casing under a wide variety of different loads and / or load changes.

[0005] Based on this, the object of the invention is to at least partially solve the problems described with reference to the prior art. In particular, a method is to be created by which a support structure can be held in the casing of the exhaust aftertreatment unit.

[0006] This object is achieved by the features of the independent claims. Further advantageous embodiments of the invention are specified in the dependent claims. It should be noted that features listed individually in the claims can be combined with one another in any technologically expedient manner and define further embodiments of the invention. Furthermore, the features listed in the claims are further specified and explained in the description, with further preferred embodiments of the inventions being presented.

[0007] An exhaust gas aftertreatment unit contributes to solving this problem, comprising at least a casing, a support structure, and a honeycomb body supported or secured to the support structure by support pins. The support structure has at least one at least partially circumferential frame that defines a base plane and an outer circumferential plane (in particular, lying transversely / perpendicularly to the base plane). The frame has a plurality of tabs that are designed transversely to the base plane. The plurality of tabs have inner sides between which the honeycomb body is arranged.

[0008] The casing can form an at least partially (tubular) channel that begins at a manifold or outlet of an internal combustion engine. Exhaust gases can flow from the internal combustion engine through the manifold into the exhaust aftertreatment unit or casing. In the exhaust aftertreatment unit, the exhaust gases can be treated, (pre-)conditioned (adapted to the required or desired conditions), and / or purified. In particular, the temperature of the exhaust gas is adjusted and / or pollutants are removed from the exhaust gas using various processes.

[0009] The casing of the exhaust aftertreatment unit can be a pipe, a pipe section, or a cover. The casing, in particular, forms a housing (or part thereof) for the exhaust gas. The casing, or the exhaust duct defined by it, usually has a central axis along which the exhaust gas flows through the pipe.

[0010] The (single-piece or multi-piece) support structure can hold or support objects in the exhaust gas aftertreatment unit. The support structure is preferably made of a metallic material. In particular, the support structure can serve to align and / or fix individual parts of an assembled honeycomb body with respect to one another. If the honeycomb body is constructed, for example, with metallic foils, these can be supported or held against the support structure, even in interior regions of the duct, to prevent undesired displacement, deformation, vibration, etc. Furthermore, it is possible to hold or align sensors of the honeycomb body and / or the exhaust gas aftertreatment unit (if provided) that protrude into the duct. A support structure can be provided upstream and / or downstream of the honeycomb body, viewed in the direction of exhaust gas flow.

[0011] The support structure can at least partially fill or cover a radially inner edge region of the casing and / or be arranged resting in / on a shoulder of the casing. The exhaust gas can flow through the support structure. The support structure is designed in particular to have as little (negative) influence on the exhaust gas flow as possible and, in particular, to avoid generating undesirably high back pressure.

[0012] The honeycomb body can be arranged on the central axis of the channel and axially offset from the support structure. A space is thus formed between the honeycomb body and the support structure along the central axis. The support pins can extend in or through the space between the honeycomb body and the support structure, in particular parallel to the central axis. The support pins are connected to the honeycomb body at one end and mounted on / at the support structure at the other end.

[0013] The honeycomb body can at least partially, preferably (almost) completely fill the channel formed by the shell in the radial direction. The (preferably all) exhaust gas flows through the honeycomb body, which is designed for this purpose with a suitable porosity or channel structure. At least the honeycomb body is arranged inside the shell or in the flow channel for the exhaust gas formed thereby. The honeycomb body can be formed with a plurality of passages, microchannels, etc., through which the exhaust gas can flow through the honeycomb body (in a main flow direction). The honeycomb body can be formed with ceramic and / or metallic material. The honeycomb body can partially or predominantly or even substantially completely cover the flow channel and can be arranged in particular at right angles to a longitudinal axis of the shell or the central axis.The honeycomb body covers at least 90% or even at least 95% of the inner surface of the shell through which the air is to flow in the main flow direction.

[0014] The honeycomb body can be designed with at least one heating path. Honeycomb bodies with at least two (separate, possibly separately controllable) tracks (heating paths) can also be used. Each track of such a heating path represents an electrical power path, with one end having a positive contact and one end having a negative contact. In honeycomb bodies with at least two tracks, these tracks can be twisted into each other. The tracks can (preferably) be formed with (electrically insulated) stacks of metal foils, for example comprising alternating corrugated and smooth (or less corrugated) metal foils, whereby the corrugations form channels for the exhaust gas to flow through, and the metal foils themselves can release heat when electrical current flows through them.The tracks can be twisted into each other or run in a meandering manner, whereby they are kept electrically insulated from each other by means of gaps and / or insulators.

[0015] The frame of the support structure can at least partially follow the geometry of an inner side of the casing. The frame can at least partially be flush with the inner side of the casing. The frame can be at least partially circumferential or completely closed.

[0016] The base plane has the outer circumference of the frame as its radial boundary. The base plane can in particular represent an at least partially oval or circular surface. At points where the frame is not closed, the base plane is alternatively delimited by an inner side of the casing. The base plane is in particular fully circumferential and closed. In most cases, the base plane is a flat surface, but in certain applications it can also be curved (concavely or convexly), with at least the circumference (or frame) lying in a common flat plane. The support structure can comprise support arms, in particular in the manner of spoke elements, which extend in or along the base plane, starting from the frame / circumference towards or in the direction of the central axis.The support structure can be designed in the manner of a spoked wheel, i.e., comprising an outer frame, an inner hub structure, and support arms extending and connecting therebetween. The support arms can be substantially straight and / or curved. It is possible for the support arms to be designed with substantially similar and / or (viewed in the circumferential direction) equally oriented radii of curvature.

[0017] An outer circumferential plane can be described or defined by an outer circumferential surface of the frame. In particular, the outer circumferential surface can be described as the circumference of the base plane continued parallel to the center axis.

[0018] The plurality of tabs with which the frame is constructed or connected can be part of the frame and extend it. The support structure with the frame, together with the plurality of tabs, can be stamped from a single component. This ensures a connection between the plurality of tabs and the frame that can meet predetermined criteria (e.g., stability, rigidity / flexibility, durability).

[0019] The tabs can all be designed to run transversely or (essentially) perpendicular to the base plane, starting from the frame. In particular, the tabs can be bent transversely to the frame that delimits the base plane. Preferably, each of the plurality of tabs is oriented or arranged to run in the same direction, starting from the frame. The plurality of tabs can thus form an extension of the frame parallel to the center axis of the casing in one direction. The support structure, with the plurality of tabs bent transversely by the frame, can form an at least partially open, circumferential enclosure that surrounds a (bordered) space axially adjacent to the base plane. Inner sides of the plurality of tabs face the center axis of the casing or the (bordered) space. Outer sides of the plurality of tabs face the casing and, in particular, lie (flush) there.

[0020] The (at least one) honeycomb body is arranged between the inner sides of the plurality of tabs or is surrounded / enclosed by them. The plurality of tabs thus runs in the casing from the frame of the support structure to the honeycomb body and parallel along the outside. The honeycomb body is thus arranged in the enclosure that forms the support structure with the frame and the plurality of tabs.

[0021] This allows the support structure to be positioned particularly in the area or particularly close to the area where the honeycomb body is positioned in the shell. In particular, similar thermal and / or flow conditions are then present, allowing the desired support to be adjusted more easily and evenly.

[0022] The at least one honeycomb body is mounted at a distance from the shell in its interior, in particular to ensure contact between the honeycomb body and the shell even under rapidly changing ambient conditions (pressure, temperature, vibration, etc.). For this purpose, in particular, an (annular) gap is formed that surrounds the honeycomb body in the circumferential direction. The gap is in particular an annular region that has an outer circumference and an inner circumference. The shape of the gap can be substantially round, oval, or the like, and is in particular adapted to the inner contour of the shell or the outer contour of the honeycomb body. The width of the gap is limited in a radial direction of the honeycomb body by an outer circumferential surface of the honeycomb body and the inner side of the shell. The height of the gap can be limited in an axial direction of the honeycomb body by the height of the honeycomb body.The height of the gap thus corresponds to the height of the honeycomb body in the axial direction of the honeycomb body. The gap should be as small / narrow as possible (from a radial perspective), as this could potentially allow bypass flow past the honeycomb body, which could negatively impact the efficiency of the honeycomb body or the exhaust gas heating device.

[0023] The plurality of tabs can extend in the axial direction of the honeycomb body between the honeycomb body and the shell in the gap parallel to the center axis. The plurality of tabs can have a length greater than the height of the gap. The plurality of tabs can thus protrude into the gap, starting from the frame, and protrude out of the gap with an axial end of the plurality of tabs. One, several, or all of the tabs can (cumulatively or alternatively) end in the gap.

[0024] The placement of the tabs in the gap can, on the one hand, help to reduce unwanted bypass of exhaust gas past the honeycomb body.

[0025] The tabs running along the gap also offer a good, enlarged attachment or alignment option for the support structure on the outer sides and / or a larger coating surface on the inner sides, with which contact with the honeycomb body can be dampened, electrically insulated and / or predefined if necessary.

[0026] The outer circumferential plane can be closed and at least partially curved. The plurality of tabs can have outer sides that follow the course of the outer circumferential plane. The outer circumferential plane can form an outer boundary of the plurality of tabs, so that the plurality of tabs can conform to the inner surface of the casing. Bends with constant and / or different radii are applied to the plurality of tabs, so that the outer sides of the plurality of tabs follow or correspond to the casing course in the circumferential and / or axial direction.

[0027] The outer sides of the plurality of tabs can be in contact with the casing (positively and / or positively). The outer circumferential plane can be designed such that the outer sides of the plurality of tabs correspond to a curvature or profile of the inner side of the casing. The outer sides of the plurality of tabs can be (additionally) firmly bonded to the casing. The outer sides of the plurality of tabs can be connected to the casing by means of a soldered or welded joint. This allows the composite of support structure, support pins, and honeycomb body in the casing to be held particularly permanently, even under high alternating loads.

[0028] A plurality of spoke elements can be at least partially connected to the frame and run parallel to the base plane. The plurality of spoke elements can span the base plane. The support pins can be mounted or fastened on the spoke elements. This makes it possible for support pins to be distributed over the entire base plane in a predetermined pattern and / or even even uniformly, in particular to also hold or axially support the inner region of the honeycomb body. At least one spoke element of the plurality of spoke elements can have an at least partially curved, S-shaped and / or meandering course. The at least one spoke element can protrude from one section of an inner side to another, spaced-off or even approximately opposite section of the inner side of the frame and thus partially or completely span the base plane.It is possible for the at least one spoke element to extend from a portion of the inner side of the frame to at least one other spoke element of the plurality of spoke elements. Furthermore, it is possible for at least one bridging element to be provided in the support structure. The at least one bridging element can extend between the plurality of spoke elements. It is also possible for the at least one bridging element to extend from at least one spoke element to at least one other spoke element of the plurality of spoke elements.

[0029] The plurality of plates can be arranged opposite (some or all) of the plurality of spoke elements on the frame. In this case, the plate can be an extension of the spoke element. Loads acting on the plurality of spoke elements can thus be directly transferred into the casing via the plurality of plates. The plate can thus be designed as a type of abutment for the spoke element on the opposite side of the frame. Preferably, plates are provided adjacent to or opposite the majority of the spoke elements, in particular for (almost) all spoke elements that terminate at the frame.

[0030] The number of spoke elements ending at the frame can correspond to the number of links. The number of spoke elements ending at the frame can be smaller or larger than the number of links, but in particular, the deviation can be a maximum of 5, 4, 3, 2, or even just 1.

[0031] It is possible for the plurality of tabs to be arranged in regions of the frame that lie between the plurality of spoke elements. For example, thermal expansion could be compensated for in regions of the frame where there is no radial support via the spoke elements. This can be provided in particular where the casing and / or the spoke element are locally exposed to particularly high thermal loads, such as when arranged particularly close to the engine and / or subject to lateral flow with hot exhaust gas. The number of tabs in regions of the frame that lie between the plurality of spoke elements is preferably a maximum of 5, 4, 3, 2, or even just 1.

[0032] The plurality of spoke elements can have receptacles, wherein the support pins are arranged in the receptacles such that the support pins protrude transversely from the base plane and are connected to the honeycomb body at one end. Preferably, at least one, in particular each, spoke element has a plurality of receptacles. In the space between the honeycomb body and the support structure, the support pins protrude in particular transversely from the base plane. The support pins are connected to the honeycomb body at one (axial) end and arranged in the receptacles at another (axial) end. The receptacles are in particular depressions in the support structure with a one-sided opening towards the space between the honeycomb body and the support structure. The support pins can extend through the opening into the receptacles. The support pins can be firmly fastened in the receptacles.

[0033] The plurality of tabs may have a transition region with the frame, which is bent. The support structure with frame, spoke elements, and tabs may be punched from a (single) sheet, with the tabs then being bent in alignment by means of a forming process. The plurality of tabs is part of the support structure and connects to the frame. In the transition region, the plurality of tabs has a bend with a bending angle in a range of 60 0 [degrees] up to 130 0 Particularly preferably, the bend has a bending angle of 90 0 on.

[0034] Particularly preferably, the bend also has a bending radius. The bending radius can be in a range from 0.5 mm [millimeters] to 5.0 mm. The bending radius is particularly preferably in a range from 1.0 mm to 3.0 mm. The bending radius can be selected depending on the thickness or sheet thickness of the support structure, so that the bending radius should in particular be greater than the thickness / sheet thickness. If the bending radius is smaller than the thickness / sheet thickness of the support structure, the risk increases that (particularly) high mechanical loads cannot be withstood in the transition area. In particular, material yield strengths can be exceeded and high forces can occur due to compression. At a bend with a bending radius that is too small, the support structure could be prone to tearing. The thickness / sheet thickness of the support structure or the tabs should in particular be selected in the range of 0.5 - 5.0 mm.

[0035] The transition region can have undercuts. An undercut can be a local reduction of the radius of the outer circumferential plane. For example, (symmetrical) undercuts (in the circumferential direction) are provided directly next to each of the plurality of tabs. The area directly next to the plurality of tabs is cut out of the frame. Preferably, the frame has a rounded notch along the outer circumferential plane in front of and behind each tab of the plurality of tabs (seen in the circumferential direction). Such an undercut can be used to achieve bends in the plurality of tabs without bending the frame.

[0036] The plurality of tabs may have undercuts and / or cross sections (in radial and / or axial direction) in front of the transition area or behind the transition area.

[0037] A cross-section can be a local reduction in the width of the plurality of tabs. Cross-sections are preferably arranged in a region within the plurality of tabs that directly adjoins the transition region. The width of the plurality of tabs can be reduced by lateral, rounded notches. Single-sided, rounded notches can be used. Particularly preferred are double-sided, rounded notches. A cross-section can be used to allow the plurality of tabs to bend with a small radius without curving the frame.

[0038] Cross-sections and undercuts can be provided in combination. Particularly preferably, cross-sections and undercuts are used together (radially) in front of a transition area. In this case, the undercuts already used in the frame are extended with cross-sections. L-shaped pieces are cut out of the frame. The L-shaped pieces can be cut out directly next to the plurality of tabs in the frame. The L-shaped pieces initially extend into the frame as undercuts next to the plurality of tabs. The undercuts are followed by cross-sections that extend to a center line of the respective tab of the plurality of tabs.Preferably, the frame has L-shaped pieces along the outer circumferential plane in front of and behind each tab of the plurality of tabs, each of which has undercuts followed by cross sections that extend to the center line of the respective tab of the plurality of tabs. The plurality of tabs can have beads running in the circumferential direction of the honeycomb body (and in particular parallel or opposite thereto) and directed towards the center axis of the shell. The beads can be a bulge transverse to the inside of the plurality of tabs. The beads can increase the stability of the plurality of tabs. It is possible for a tab of the plurality of tabs to have more than one bead.

[0039] The invention and the technical environment are explained in more detail below with reference to six figures. The representations are schematic and not intended to illustrate proportions. The explanations given with reference to individual details of the figure are extractable and can be freely combined with facts from the above description, unless something else necessarily follows for a person skilled in the art or such a combination is explicitly excluded. It shows schematically:

[0040] Fig. 1 : Support structure,

[0041] Fig. 2: Detailed view of a tab with cross sections,

[0042] Fig. 3: Detailed view of a tab with undercuts and cross sections,

[0043] Fig. 4: Detailed view of a tab with bead,

[0044] Fig. 5: Detailed view of a tab with undercuts and

[0045] Fig. 6: Sectional view of the exhaust aftertreatment unit.

[0046] Fig. 1 shows a support structure 5. The support structure 5 comprises spoke elements 13 and a frame 6, which together span a base plane 8. Connected to the frame 6 are tabs 7, which extend transversely to the base plane 8. The tabs 7 are part of the support structure 5. The tabs 7 are arranged at approximately equal distances from one another along the circumference along an outer circumferential plane 10 of the frame 6. The tabs 7 have outer sides 11, which are located on / in the outer circumferential plane 10.

[0047] Furthermore, the tabs 7 have inner sides 9 that point toward a center axis 20 of the support structure 5. The tabs 7 are connected to the frame 6 via transition areas 14. The transition areas 14 have a bend with a radius. Receptacles 16 are arranged on the spoke elements 13 of the support structure 5. The frame 6 also has undercuts 15. Undercuts 15 are arranged in front of and behind the tabs 7 along the outer circumferential plane 10. An undercut 15 is a local reduction of a radius of the outer circumferential plane 10.

[0048] Fig. 2 shows a detailed view of a link plate 7 with cross sections 17. The link plate 7 is arranged opposite one end of a spoke element 13 on the frame 6 with the transition region 14. The inner side 9 of the link plate 7 points to a center axis 20 (not shown here). Cross sections 17 are arranged on the link plate 7 behind the transition region 14. The cross sections 17 represent a local reduction of the width of the link plate 7 on both sides. Fig. 2 also shows how the link plate 7 conforms to a casing 2.

[0049] Fig. 3 shows a detailed view of the tab 7 from Fig. 2 with undercuts 15 and cross sections 17. It can be seen how undercuts 15 protrude from both sides of the tab 7 into the frame 6. Cross sections are attached to the undercuts 15.

[0050] 17, which extend the undercuts 15. The transition area 14 of the tab 7 is arranged behind the cross sections 17 and the undercuts 15.

[0051] Fig. 4 shows a detailed view of the tab 7 from Fig. 2 with a bead 18. The bead 18 is arranged behind the transition area 14 of the tab 7. The bead

[0052] 18 runs in the circumferential direction and extends transversely inwards towards the central axis 20 (not shown here).

[0053] Fig. 5 shows a detailed view of a tab 7 with undercuts 15. The tab 7 is arranged on the frame 6 in an area between two spoke elements 13.

[0054] Fig. 6 shows a sectional view of the exhaust aftertreatment unit 1. It can be seen how the tab 7 extends into a gap 12 formed between the casing 2 and the honeycomb body 3. The gap 12 is limited in height by a height of the honeycomb body 3 and in width by a radial distance between the honeycomb body 3 and the casing 2. The transition region 14 is arranged outside the gap 12 (viewed in the axial direction).

[0055] It can also be seen how the spoke element 13 of the support structure 5 is connected to the honeycomb body 3 in a space 19 via support pins 4. The space 19 is limited in width by a width of the honeycomb body 3 and in height by an axial distance of the honeycomb body 3 from the support structure 5.

[0056] Exhaust gas can flow through the exhaust aftertreatment unit 1 shown in Fig. 6. The exhaust gas first passes through the support structure 5 and then flows through the chamber 19 and then the honeycomb body 3. The exhaust gas thus flows along an inner side of the casing 2 and, in the area of ​​the tab 7, along the inner side of the tab 7.

[0057] The arrangement shown can generally be flowed through by exhaust gas from above or below. It is also possible to provide two support structures 5, one upstream and one downstream, with their tabs 7, optionally interlocking in the circumferential direction, together forming a housing for the honeycomb body 3 or holding / supporting it on both sides by means of support pins 4.

[0058] Reference symbol

[0059] 1 exhaust aftertreatment unit

[0060] 2 coats

[0061] 3 honeycomb bodies

[0062] 4 support pin

[0063] 5 Support structure

[0064] 6 frames

[0065] 7 tab

[0066] 8 Ground level

[0067] 9 Inside

[0068] 10 outer circumference level

[0069] 11 Outside

[0070] 12 gap

[0071] 13 spoke element

[0072] 14 Transition area

[0073] 15 undercut

[0074] 16 recording

[0075] 17 Cross section

[0076] 18 bead

[0077] 19 Room

[0078] 20 Center axis

Claims

Claims 1. Exhaust aftertreatment unit (1 ), comprising at least one casing (2), a support structure (5), and a honeycomb body (3) supported or fastened to the support structure (5) by support pins (4), wherein the support structure (5) has at least one at least partially circumferential frame (6) which defines a base plane (8) and an outer circumferential plane (10), wherein the frame (6) has a plurality of tabs (7) which are designed transversely to the base plane (8), wherein the plurality of tabs (7) have inner sides (9) between which the honeycomb body (3) is arranged.

2. Exhaust aftertreatment unit (1) according to the preceding claim, wherein a gap (12) is formed between the casing (2) and the honeycomb body (3), into which gap the plurality of tabs (7) extend.

3. Exhaust aftertreatment unit (1) according to one of the preceding claims, wherein the plurality of tabs (7) are integrally connected to the casing (2) on their outer sides (11).

4. Exhaust aftertreatment unit (1) according to one of the preceding claims, wherein a plurality of spoke elements (13) are at least partially connected to the frame (6) and run parallel to the base plane (8).

5. Exhaust aftertreatment unit (1) according to claim 4, wherein the plurality of tabs (7) are arranged opposite the plurality of spoke elements (13) on the frame (6).

6. Exhaust aftertreatment unit (1) according to claim 4 or 5, wherein the plurality of tabs (7) are arranged on regions of the frame (6) which lie between the plurality of spoke elements (13).

7. Exhaust aftertreatment unit (1) according to one of the preceding claims, wherein the plurality of spoke elements (13) have receptacles (16), wherein the support pins (4) are arranged in the receptacles (16), so that the support pins (4) protrude transversely from the base plane (8) and are connected at one end to the honeycomb body (3).

8. Exhaust aftertreatment unit (1) according to one of the preceding claims, wherein the plurality of tabs (7) has a transition region (14) with the frame (6) which is bent.

9. Exhaust aftertreatment unit (1) according to claim 8, wherein the transition region (14) has undercuts (15).

10. Exhaust aftertreatment unit (1) according to claim 8 or 9, wherein the plurality of tabs (7) have undercuts (15) and / or cross sections (17) in front of the transition region (14) or in the transition region (14) or behind the transition region (14).

11. Exhaust aftertreatment unit (1) according to one of the preceding claims, wherein the plurality of tabs (7) have beads (18) extending in the circumferential direction of the honeycomb body (3) and directed towards a central axis (20) of the casing (2).

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