Exhaust gas aftertreatment device with slotted substrate
By designing metal foil with overlapping slots in the wound state in the internal combustion engine exhaust honeycomb body, the torsion problem caused by temperature gradient is solved, the durability and flexibility of the device are improved, and structural damage is avoided.
Patent Information
- Application Number
- CN202380079859.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-11-18
- Filing Date
- 2023-11-09
- Publication Date
- 2025-07-11
AI Technical Summary
In the prior art, the internal combustion engine exhaust honeycomb body is subject to torsion and structural damage caused by temperature gradient, especially under high temperature loads, which are prone to failure of components.
The matrix formed by a plurality of metal foils is used. The slots overlap with each other in the wound state to form axial and radial extension portions. The length of the slots is much larger than the width to evenly distribute stress to avoid torque generation and structural damage.
Effectively reduce or inhibit the matrix torsion caused by temperature, improve the flexibility and durability of the matrix, and avoid irreversible damage caused by torsion.
Smart Images
Figure CN120303470A_ABST
Abstract
Description
Field of the Invention
[0001] The present invention relates to a device for post-treatment of exhaust gas, in particular for treating the exhaust gas of an internal combustion engine, wherein the device is arranged or can be arranged in an exhaust gas path through which the exhaust gas can flow, and can be flowed through from the gas inlet side to the gas outlet side along a main flow direction defined by a plurality of flow channels formed in a matrix. The matrix is formed by a plurality of metal foils stacked on top of each other to form a laminated structure and wound around at least one rotation point, wherein the matrix has an axial extension extending in the main flow direction and a radial extension extending transversely to the axial extension. Background Art
[0002] In order to perform post-treatment of the exhaust gas of an internal combustion engine, in particular to convert the pollutants contained in the exhaust gas, different catalysts can be installed in the exhaust gas path. The catalyst usually has a honeycomb body through which a plurality of flow channels can flow, and the honeycomb body has a catalytically active surface on which chemical reactions of pollutants occur to generate harmless products.
[0003] Known metal honeycomb bodies are formed by a plurality of metal foils stacked to form a laminated structure and truncated to a defined length. The stacked metal foils are at least partially wound or coiled around at least one rotation point in this case, thereby forming a honeycomb body. For the honeycomb body, smooth or unstructured metal foils can be used, or at least segmentally or continuously structured metal foils can be used, and these metal foils are preferably stacked alternately. So-called cells are formed between the metal foils, and these cells form flow channels of the honeycomb body through which flow can occur along the main flow direction from the gas inlet side to the outlet side.
[0004] The honeycomb body (also called a carrier matrix) thus produced can then be pressed into a housing called a carrier tube and welded thereto. In known configurations, both (completely) smooth metal foils and at least segmentally structured metal foils continuously extend over the entire axial extension of the honeycomb body. It is also possible to produce the carrier matrix entirely from structured metal foils, where these structures are arranged at an angle to each other, for example, so that the metal foils do not hook onto each other.
[0005] The disadvantages of the known solutions in the prior art are particularly that the known honeycomb body is integrally designed along its axial extension, so its flexibility is limited.
[0006] It has also been found that due to the heat capacities of the metal foil and the carrier tube, radial and axial temperature differences occur in the honeycomb body during rapid heating or rapid cooling. These temperature gradients cause torsional loads to occur between the cold and hot zones of the honeycomb body in the axial direction, and this load is transmitted through the metal foil in the form of tangential shear forces.
[0007] Particularly under high-temperature loads, a temperature gradient is generated along the axial extension of the substrate from the extremely hot gas inlet side to the relatively cold gas outlet side. This temperature difference generates a torque within the substrate, causing the hot gas inlet to twist relative to the relatively cold gas outlet. When the elastic deformation is exceeded, this torsion may lead to irreversible damage to the substrate and, in the worst case, component failure. Summary of the Invention
[0008] Therefore, the task of the present invention is to at least partially solve the problems described with respect to the prior art, in particular to provide a device with a honeycomb body, which is designed to particularly reduce or even suppress the temperature-induced substrate torsion and / or resist the structural damage of the substrate.
[0009] The task regarding the device is solved by a device having the features of claim 1. Advantageous improvements are given in the dependent claims. The features listed separately in the claims can be combined with each other and / or arbitrarily combined with the features in the description. The description (especially in conjunction with the drawings) explains the present invention and gives additional implementation variants.
[0010] For this purpose, a device for exhaust gas aftertreatment is used, in particular for treating the exhaust gas of an internal combustion engine. The device can be arranged in an exhaust gas path through which the exhaust gas can flow and can be flowed through from the gas inlet side to the gas outlet side along the main flow direction defined by a plurality of flow channels formed in the substrate. The substrate is formed by a plurality of metal foils stacked on top of each other to form a laminated structure and wound or coiled around at least one rotation point. Here, the substrate has an axial extension extending in the main flow direction and a radial extension extending transversely to the axial extension. Here, all the metal foils have a plurality of slots, and the slots of each metal foil coincide with each other in the wound state and extend along the circumferential direction of the substrate.
[0011] It is particularly advantageous to arrange slots in all the metal foils because this avoids the foils being subjected to different intensities of force (especially torque) due to different numbers of slots and / or mutually twisted positions, thereby avoiding a critical stress state in the substrate.
[0012] Therefore, the number and arrangement of slots in each metal foil are the same in order to generate a uniform stress state in each metal foil under thermal load. The slots are primarily used for the mechanical unloading of the metal foils and should prevent the generation of high torque or reduce the influence of torque on the substrate. The (main) purpose of the slots is not to promote the cross-flow of exhaust gas between different (mutually parallel or adjacent) flow channels. Therefore, the length of the slots measured along the circumferential direction of the substrate is several times greater than the width measured along the axial direction / axial extension of the substrate.
[0013] The substrate may include a plurality of laminated structures. At least one laminated structure may be wound (gewickelt) and / or coiled (gewunden) around at least one rotation point.
[0014] "Coincidence" in this context particularly means that, in the wound state of the metal foil, the slots or the same number of slots are located in the axial cross-sectional plane. "Coincidence" in this context also particularly means that, in the wound state of the metal foil, the slots or the same number of slots overlap on the radial extension. The overlapping slots may jointly form one or more slot gaps in the substrate.
[0015] The wound state particularly occurs when the metal foil or the substrate is fixedly mounted in a housing or a carrier tube.
[0016] The circumferential direction is particularly characterized by the orientation of the metal foil in the wound state, perpendicular to the axial extension of the substrate.
[0017] Preferably, the length of the slot is at least 20 times its width. Particularly preferably, the length of the slot is even 50 times its width. However, in an advantageous design, the length of the slot can also be 500 times its width or more.
[0018] Particularly advantageously, the metal foil has a slot pattern with exactly two slots each in the circumferential direction, wherein a plurality of mutually spaced slot patterns are arranged on the axial / axial extension.
[0019] The slot pattern particularly refers to the number of slots and their positions relative to each other, especially in a metal foil. Thus, the slot pattern in the circumferential direction describes the number of slots spaced apart from each other in the circumferential direction in a predetermined axial plane. A plurality of circumferential slot patterns can be arranged at intervals in the axial direction in the metal foil. The sum of the slot patterns in the circumferential direction of the metal foil can be referred to as the total slot pattern of the metal foil.
[0020] It is advantageous to arrange two slots each in the circumferential direction, because this specifically improves the flexibility of the substrate, so that interfering force actions can be compensated within the elastic deformation range. At the same time, the durability and stability of the substrate required for use in the exhaust gas path will not be significantly reduced.
[0021] It is also advantageous that the exactly two slots of the slot pattern are separated from each other by an intermediate rib and are respectively separated from the respective edges of the metal foil by edge ribs. The intermediate rib and the edge ribs are formed from the material of the metal foil. By respectively arranging edge ribs at the layer termination or ends of the circumferential metal foil (i.e., before and after the circumferential slots), it is ensured that each metal foil has sufficient stability so that it will not tear on the one hand during the assembly process and will not suffer structural damage during use on the other hand.
[0022] One preferred embodiment is characterized in that the individual metal foils (in particular depending on their position in the laminate structure) have slots of different lengths in the circumferential direction. The slot lengths are selected such that in the wound state of the substrate, the slots of the individual metal foils coincide with each other.
[0023] By winding or coiling the metal foils to form the substrate, regions of different bending radii are produced in the metal foils, here referring to the (overall, übergeordnete) orientation of the metal foils rather than the (inherent) structuring. The region near the middle of the substrate has a smaller bending radius than the radially outer edge region of the substrate. If the slot lengths of all the metal foils were exactly the same, winding would sometimes cause a misalignment between the slots of the individual metal foils, because the arc length of the slots in the region of the larger bending radius is shorter than that in the region of the smaller bending radius. This phenomenon can be compensated for by adjusting the circumferential slot lengths and ensuring that the slots coincide precisely in the wound state.
[0024] In other words, the slot lengths are selected according to the bending radius of the metal foils in the slot region in the wound state.
[0025] The metal foils can be formed with different lengths in the circumferential direction of the wound substrate. The advantage of this is that, especially in the end regions forming the ends of the foils, the individual metal foils terminate slightly misaligned, thus producing a more precise forming adaptation for the substrate. Especially in a typical circular cross-section, this enables a more precise forming.
[0026] Furthermore, it is advantageous if the length of the intermediate ribs and / or the edge ribs is 0.5 mm to 50.0 mm [millimeters], preferably 1.0 mm to 10.0 mm, particularly preferably 1.5 mm to 5.0 mm. Compared to the circumferential extension of the metal foils and the circumferential length of the slots, the intermediate ribs and the edge ribs are preferably very short (especially several times shorter). The ribs are especially used to generate a sufficiently high overall stability to ensure the assembly and safe operation of the substrate.
[0027] The width of the slots can be 0.1 mm to 10.0 mm [millimeters], preferably 0.1 mm to 2.0 mm, particularly preferably 0.1 mm to 0.5 mm. The slots are preferably very narrow or are formed with the extremely small widths given here. This is especially used to prevent the exhaust gas from flowing through these slots and at least to keep the flow-through at the lowest possible level. The slots do not have a (significant or essential) guiding function and (in fact) are only used to produce a sufficiently flexible structure of the substrate.
[0028] In an extreme design, the width of the slots can even approach 0.0 mm (the so-called zero clearance). In this case, the edges bounding the slots are in direct contact with each other. Depending on the stress state in the substrate, the edges bounding the slots can be in complete or only partial contact. In this design, when cutting the slots, (only or so) the base material is separated, i.e., no material is removed.
[0029] The slots can divide the metal foil into multiple axial segments, where the length of one axial segment is from 1.0 mm to 50.0 mm [millimeters], preferably from 5.0 mm to 30.0 mm, and particularly preferably from 10.0 mm to 20.0 mm. The more axial segments are formed along the length of the substrate, the more flexible the substrate is, and thus it can withstand higher forces without damage. The number of axial segments can be selected from the following group: 2, 3, 4, 5, 6, 7, 8, 9, 10.
[0030] The intermediate ribs between the respective (circumferential) slot patterns can be aligned on the axial / axial extension such that the slots are also aligned with each other along the axial extension. This is beneficial for bearing the forces acting on the (wound) substrate as evenly as possible and not generating a non-uniform stress state on the axial extension of the substrate.
[0031] The (circumferential) slot patterns can be arranged equidistantly (i.e., at the same spacing) from each other along the axial extension. This is beneficial for making the stress distribution on the substrate as uniform as possible. Description of the Drawings
[0032] The present invention and its application environment will be described in detail below with reference to the schematic diagrams through embodiments. It should be noted that in the drawings, elements denoted by the same reference numerals may have the same characteristics, unless otherwise specified herein. The elements shown in the drawings may be further defined by the features in other drawings and / or the description and / or the claims (and vice versa), unless explicitly excluded below.
[0033] In the drawings:
[0034] Figure 1 is a perspective view of a corrugated metal foil with a slot pattern,
[0035] Figure 2 is Figure 1 a detail view of the corrugated metal foil in
[0036] Figure 3 is a schematic view of a slotted substrate in a sleeve, and
[0037] Figure 4 is a perspective view of an exhaust gas aftertreatment device having a substrate in a sleeve. Detailed Description of the Embodiments
[0038] Figure 1 A view showing the structured metal foil 1 is presented. The metal foil 1 has a length L, which corresponds to the axial extension of the wound substrate. In addition, the metal foil 1 has a width B, which runs circumferentially or perpendicular to the axial extension in the finally assembled substrate.
[0039] The metal foil 1 has a plurality of slots 2 which run in the width B or circumferentially and are arranged equidistantly from one another along the length L. In the width B, two slots 2 each are spaced from one another by an intermediate rib (Mittelsteg) 3 (see also enlarged detail). The slots 2 are each spaced from the edge or end region of the metal foil 1 by the width of an edge rib 4. The slots 2 result in a plurality of axial segments 5 along the length L.
[0040] Figure 2 A detail view of the metal foil 1 is shown. It can be seen that a smooth metal foil 6 is arranged below the corrugated metal foil 1. The metal foils 1, 6 overlap one another. The same slot pattern is formed in the two metal foils 1, 6 and is arranged overlapping one another.
[0041] In Figure 2 the edge rib 4 can also be clearly seen (see also enlarged detail), which is formed between the slot 2 and the end of the foil.
[0042] Figure 3 A view of the substrate 8 accommodated in the sleeve 7 is shown, which substrate is formed by Figure 1 and Figure 2 the metal foils 1 and 6. The axial segments 5 of the metal foils 1, 6 are visible along the axial extension, which axial segments are formed or bounded by the slots 2. In addition, the edge ribs 4 can be seen at the circumferentially aligned ends of the foils.
[0043] Figure 4 A schematic view of a device for exhaust gas aftertreatment, in particular for treating the exhaust gas of an internal combustion engine, is shown, which device can be arranged in an exhaust gas path through which the exhaust gas can flow (dashed line). The device includes a substrate 8 in which a plurality of (parallel) flow channels 9 are formed, which flow channels can be flowed through from a gas inlet side (front view) to a gas outlet side (not shown rear view) in a defined main flow direction (along the axial extension L). The substrate 8 includes a plurality of metal foils 1, 6 stacked in a laminated structure and wound around at least one pivot point 10 (here in an S-shape around two pivot points 10). The substrate 8 has an axial extension L running in the main flow direction and a radial extension or circumference B running transversely to the axial extension L.
[0044] Figures 1 to 4 The embodiments of
[0045] List of reference numerals
[0046] 1 Corrugated metal foil
[0047] 2 Slot
[0048] 3 Intermediate rib
[0049] 4 Edge rib
[0050] 5 Axial segment
[0051] 6 Smooth metal foil
[0052] 7 Sleeve
[0053] 8 Substrate
[0054] 9 Flow channel
[0055] 10 Rotation point
[0056] 11 Edge rib
[0057] L Substrate length (axial extension)
[0058] B Substrate width (circumferential)
Claims
1. Device for post-treatment of exhaust gases, in particular for treating the exhaust gases of an internal combustion engine, wherein, The device can be arranged in an exhaust gas path through which exhaust gas can flow, and can be flowed through from the gas inlet side to the gas outlet side along a main flow direction defined by a plurality of flow channels (6) formed in a matrix (8), wherein the matrix (8) is formed by a plurality of metal foils (1, 6) stacked on top of each other to form a laminated structure and wound around at least one rotation point, and wherein the matrix (8) has an axial extension extending in the main flow direction and a radial extension extending transversely to the axial extension, characterized in that all the metal foils (1, 6) have a plurality of slots (2), and wherein the slots (2) of each metal foil (1, 6) coincide with each other in the wound state and extend in the circumferential direction of the matrix (8).
2. The device according to claim 1, characterized in that, The metal foils (1, 6) each have a slot pattern with exactly two slots (2) in the circumferential direction, and a plurality of the slot patterns are arranged at intervals in the axial direction.
3. The device according to claim 2, wherein The exactly two slots (2) of the slot pattern are separated from each other by an intermediate rib (3) and are separated from the respective edges of the metal foils (1, 6) by edge ribs (4), respectively.
4. The device according to any one of the preceding claims, characterized in that The slots (2) of each metal foil (1, 6) have different lengths in the circumferential direction.
5. The device according to claim 4, characterized in that, The slot length is selected according to the bending radius of the metal foil (1, 6) in the region of the slot (2) in the wound state.
6. The device according to any one of the preceding claims, characterized in that The metal foils (1, 6) are formed with different lengths in the circumferential direction of the wound matrix (8).
7. The device according to any one of the preceding claims, characterized in that The length of the intermediate rib (3) and / or the edge rib (4) is 0.5 mm to 50 mm, preferably 1 mm to 10 mm, and particularly preferably 1.5 mm to 5 mm.
8. The device according to any one of the preceding claims, characterized in that The width of the slot (2) is 0.1 mm to 10 mm, preferably 0.1 mm to 2 mm, and particularly preferably 0.1 mm to 0.5 mm.
9. The device according to any one of the preceding claims, characterized in that, The slot (2) divides the metal foil (1, 6) into a plurality of axial segments (5), and the length of one axial segment (5) is 1 mm to 50 mm, preferably 5 mm to 30 mm, and particularly preferably 10 mm to 20 mm.
10. The device according to any one of the preceding claims, characterized in that, The intermediate ribs (3) between the respective slot patterns are aligned axially so that the slots (2) are also aligned with each other along the axial extension.
11. The device according to any one of the preceding claims, characterized in that, The slot patterns are arranged equidistantly from each other along the axial extension.