Honeycomb body
The honeycomb structure addresses durability and expansion issues by employing varying prestress sections and structured foils with alternating corrugations to optimize bonding and flow patterns, resulting in improved structural integrity and performance.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- EMITEC TECH GMBH
- Filing Date
- 2025-12-16
- Publication Date
- 2026-06-25
AI Technical Summary
Existing honeycomb structures for exhaust aftertreatment systems face issues with unpredictable expansion behavior and reduced durability due to carbon diffusion and carbide precipitation, particularly in high-surface-pressure contact zones, which impair the mobility and bonding of metallic foils.
A honeycomb structure with varying prestress sections, where the first section has a higher prestress to enhance material-bonded connections and the second section has reduced prestress to prevent unwanted bonding, using structured metallic foils with alternating corrugation orientations to create a zigzag flow pattern and minimize undesired material-bonded connections.
The solution ensures predictable expansion behavior and increased durability by promoting targeted material-bonded connections in high-pressure zones while reducing bonding in low-pressure zones, enhancing the structural integrity and performance of the honeycomb structure.
Smart Images
Figure EP2025087332_25062026_PF_FP_ABST
Abstract
Description
[0001] honeycomb body
[0002] The present invention relates to a honeycomb structure.
[0003] A honeycomb body comprises a casing tube and a honeycomb structure arranged within the casing tube. The casing tube extends along an axial direction between an open first end face and an open second end face.
[0004] The honeycomb structure is formed by at least one structured metallic foil, which is stacked, wound or twisted at least on top of each other and thus forms channels through which a fluid can flow, extending from a fluid inlet side arranged at the first end face to a fluid outlet side arranged at the second end face.
[0005] The film, which has a (well) structure, is used, for example (but possibly not exclusively), to form a honeycomb structure within a honeycomb body for exhaust aftertreatment, such as that used in particular as a catalyst support in the exhaust systems of mobile internal combustion engines. Such a honeycomb structure or honeycomb body provides, in particular, a large surface area on which catalytically active material is positioned and brought into contact with the exhaust gas (fluid) flowing through the honeycomb body. The invention is particularly applicable to exhaust gas purification in motor vehicles or also in stationary or other mobile systems.
[0006] Numerous different designs of honeycomb bodies for exhaust aftertreatment have already been proposed. A honeycomb structure can be constructed with smooth and / or textured layers or (sheet) foils. These foils can be layered, wound, and / or coiled and finally placed in a housing (jacket tube) of the honeycomb body, creating a multitude of channels through which the exhaust gas flows. These channels can, for example, extend in a straight, coiled, and / or oblique manner between the end faces of such a honeycomb body. Foils for such honeycomb bodies or honeycomb structures are typically manufactured using a rolling and / or corrugating process. During this process, carbon, originating from the foils themselves or from the lubricant used in the process, can be deposited on the foil surfaces.
[0007] The films are also regularly subjected to heat treatment, for example, as part of a high-temperature soldering process, in which the films of a honeycomb structure are joined together via solder joints. As a result of the heating, the carbon diffuses into the film, resulting in a high concentration of carbon in the edge region of the film.
[0008] During the cooling process following heat treatment, the carbon solubility of the metallic foil, e.g., ferritic, decreases. In this process, the carbon forms a compound with, for example, chromium, which is regularly present in the foil as an alloying element. The resulting chromium carbide is precipitated from the foil material. At the contact points between the foils of the honeycomb structure, (metallic) bonds can thus form between the foils, created by the carbide precipitates.
[0009] These connections can impair the relative mobility of the films, particularly in the inner areas of the honeycomb structure, and thus influence the expansion and expansion behavior of the honeycomb body or structure. They therefore represent a significant factor influencing the durability of the honeycomb body.
[0010] In addition to other factors (carbon content, surface properties of the metallic foil, etc.), another significant influencing factor for the formation of these compounds (through carbide precipitation) is the local surface pressure. Particularly in the applicant's known CS design (skew corrugated layers without a flat layer, see, e.g., DE 10 2012 004 918 A1), this surface pressure is comparatively high due to the reduced length of the contact zones between adjacent corrugated layers. From DE 10 2012 004 918 A1, a honeycomb structure is known in which the structured layers have a corrugated structure, with adjacent layers exhibiting intersecting corrugated structures.
[0011] In a honeycomb structure with intersecting corrugated layers, the channels of the structured layers exhibit a defined angle of inclination to the axial direction. Alternating stacking of the structured layers, each with the channels oriented in the opposite direction, creates a three-dimensional pattern of contact zones in which adjacent corrugated layers intersect and touch, thus eliminating the need for (unstructured) smooth films between the corrugated (structured) films.
[0012] The object of the present invention is to at least partially solve the problems cited with reference to the prior art. In particular, a honeycomb structure is to be provided which is particularly suitable for the targeted formation of a material-bonded connection between the contacting films, so that a predictable expansion behavior and the longest possible durability of the honeycomb structure can be achieved by the known joining methods (soldering, welding).
[0013] A honeycomb structure with the features according to claim 1 contributes to solving these problems. Advantageous further developments are the subject of the dependent claims. The features listed individually in the claims can be combined in a technologically meaningful way and can be supplemented by explanatory details from the description and / or details from the figures, thereby demonstrating further embodiments of the invention.
[0014] A honeycomb body is proposed, comprising at least a casing tube and a honeycomb structure arranged within the casing tube. The casing tube extends along an axial direction between an open first end face and an open second end face. The honeycomb structure is formed by at least one structured metallic foil, which is stacked, wound, or twisted, thus forming channels through which a fluid can flow. The channels extend from a fluid inlet side located at the first end face to a fluid outlet side located at the second end face. The honeycomb structure has several disk-shaped sections arranged side by side along the axial direction, each with a different preload within the casing tube.
[0015] The prestress o is defined as an area excess of a first cross-sectional area Q-, which exists in a load-free state compared to a second cross-sectional area Q2 of the honeycomb structure, which is limited by an inner circumference of the casing tube, i.e. o = (QT - Q2) / Q2.
[0016] The honeycomb structure is arranged at least in a first section, located on the fluid inlet and outlet sides and extending along the axial direction, with a first prestress in the casing tube that is higher than a second prestress in a second section that adjoins the first section.
[0017] Various honeycomb structures are known, and at least one of the following characteristics must be considered in their construction: winding type, casing cross-section, and cell geometry. "Winding type" refers to the orientation of the foils in an end-face view of the foil stack or honeycomb structure. Known winding types include, for example, the spiral shape, the S-shape, the V-shape, and the W-shape. Regarding the casing cross-section of the outer tube, almost all conceivable shapes are known, in particular round, oval, polygonal, triangular, or combinations thereof. Cell geometry essentially refers to the cross-section of the channels, with triangular, sinusoidal, rectangular, round, or similar cell geometries known, which are subsequently subsumed under the term "structure." For the term "pretension," it must be considered that the outer shape of the foil stack or honeycomb structure...The honeycomb structure has a first cross-sectional area (perpendicular to the axial direction) that is a certain proportion larger than the second cross-sectional area of the housing, which is bounded by the inner surface or the inner circumference of the casing tube. This means that it is not possible to insert the foil stack or the honeycomb structure into the casing tube without the honeycomb structure being in contact with the inner surface of the casing tube. Consequently, the honeycomb structure must be compressed for insertion into the casing tube, and then, once the honeycomb structure is positioned inside the casing tube, a force or pressure is exerted on the honeycomb structure via the casing tube, which is referred to here as "preload." In this context, the excess area is a suitable characteristic value to measure the preload.Accordingly, a prestress of, for example, 5% is understood below to mean that a first cross-sectional area of the honeycomb structure is 5% larger in area than a second cross-sectional area (of the honeycomb structure arranged in the casing tube), which is limited by the inner circumference of the casing tube.
[0018] The first cross-sectional area can be determined, particularly theoretically. It exists, in particular, when all sheets of the honeycomb structure are arranged without gaps to each other in all areas of the honeycomb structure, without any elastic or plastic deformation of the structure occurring.
[0019] The sections are particularly disc-shaped and each has the second cross-sectional area of the casing tube surrounding them in the section, or extends to the inner circumferential surface of the casing tube.
[0020] According to a first embodiment, the casing tube has a first inner circumference in the region of the first section, designed to generate the first prestress, and a second inner circumference in the region of the second section, designed to generate the second prestress, wherein the first inner circumference is smaller than the second inner circumference. In particular, a second cross-sectional area of the honeycomb structure present in the first section is smaller than a second cross-sectional area present in the second section. Thus, for example, the inner diameter of the casing tube is smaller in the region of the first section than in the region of the second section.
[0021] In particular, the first cross-sectional area is the same size in the first section and in the second section.
[0022] In particular, the honeycomb structure in the first section is compressed or prestressed more strongly by a local constriction of the casing tube than in the second section. This allows for an increased surface pressure in the contact zones of the first section, so that preferentially, metallurgical bonds are formed between the contacting films (e.g., through carbide precipitates).
[0023] In contrast, the honeycomb structure in the area of the second section is prestressed to a lesser degree, so that the formation of material-bonded connections is prevented or at least reduced there.
[0024] In particular, a casing tube can be provided, and then the honeycomb structure can be inserted into the casing tube through one of its end faces. The cross-section of the casing tube can be reduced either before or after the honeycomb structure is inserted, for example, in the area of the first section, so that a predetermined prestress is applied there.
[0025] According to a second embodiment, the structure of the at least one film is a corrugation having a height along a radial direction transverse to the axial direction, wherein the at least one film has a structure with a first height in the first section and a structure with a second height in the second section, the first height being greater than the second height. The first cross-sectional area in the first section is larger than the first cross-sectional area in the second section. In particular, the honeycomb structure is formed exclusively by at least one film having a structure with a first height in the first section and a structure with a second height in the second section.
[0026] When such a film is wound up, for example, in the first section, each additional layer creates another structure with a first height on top of the other structures with a first height. The same applies to structures with a second height in the second section. This means that with each layer of winding, the first cross-sectional area becomes larger in the first section than in the second section. The diameter of the honeycomb structure in the first section then corresponds, for example, to the number of windings multiplied by the first height, while the diameter of the honeycomb structure in the second section corresponds to the number of windings multiplied by the second height. The same applies to coiled films or coiled stacks of films, as well as to stacks of films.
[0027] Such a film can be produced, for example, through a two-stage forming process. In the first stage, a uniform structure is created across the entire film. In the second stage, sections of the film can then be further formed. In particular, the height of the structure is increased in the second stage, thus creating a first section. Alternatively, the channel shape or corrugation of the film (e.g., from sinusoidal to zigzag or other) can be modified. Specifically, the distance between two adjacent corrugation crests or troughs remains unchanged. Specifically, the cross-sectional area of each channel formed by the film's structure within the honeycomb structure is modified so that this cross-sectional area is larger in the first section than in the second section.
[0028] In particular, features of the first and second embodiments can also be implemented together. Specifically, the honeycomb structure comprises at least one stack formed by the film, wherein the corrugation (or the structure formed as corrugation) has a plurality of parallel troughs and crests, each extending at an angle of inclination to the axial direction of greater than zero degrees and at most 15 degrees along a direction of travel. The stack and the channels are formed by placing another structured area of the same film (e.g., if it is folded) or by placing a further structured film (with the same structure, but oriented in the opposite direction) on top of the film. The other area of the film or the further film is structured such that the overlapping troughs and crests intersect.
[0029] In particular, the wave troughs and crests each extend at an angle of inclination to the axial direction of greater than one degree, preferably greater than two or even three degrees. In particular, the angle of inclination is at most 15 degrees, preferably at most 12, at most 10, or even at most eight degrees. If such films are arranged one on top of the other with intersecting orientations, the angles between the contacting wave troughs and crests correspond to the sum of the angles of inclination of each film.
[0030] The at least one film can be arranged, for example, in a spiral shape around a central axis extending parallel to the axial direction. In particular, two films or multiples thereof are used, where a pair of films may have the same structure (type, size, etc.), but with different corrugation orientations, so that the troughs and crests of the contacting films intersect.
[0031] The film's structure is preferably formed across the entire extent of the honeycomb structure, i.e., between the fluid inlet and outlet sides. The corrugation is created by raised areas (wave crests) and depressions (wave troughs). These wave crests and troughs alternate regularly. In cross-section, the wave crests and troughs can form a sinusoidal wave pattern, a zigzag shape, or similar.
[0032] The arrangement of the structure, specifically the wave crests and troughs within the honeycomb structure, is such that they run obliquely to the axial direction. This creates channels for a fluid that are not parallel to the axial direction, but rather at an angle. Therefore, if an exhaust gas flow or fluid flow strikes an end face of the honeycomb structure or a fluid inlet face of the honeycomb structure perpendicularly, the exhaust gas / fluid is first divided because it enters the channel openings formed by the wave crests and troughs and is then deflected within the honeycomb structure. The structure is particularly distinctive in that the wave crests and troughs in adjacent areas (viewed radially from the center point of the honeycomb structure's cross-sectional area) are inclined differently or have a different orientation. For example, if...If a deflection to the right occurs in one area, it is preferred that a deflection to the left occurs in the more inward area, or vice versa. It is particularly preferred that this alignment or orientation alternates continuously when viewed in the radial direction. This results, in particular, in the wave crests and troughs not lying on top of each other at least partially, and preferably not at any point on the honeycomb structure, but rather intersecting each other and thus essentially forming only point-like contact points or zones. This creates a structure in which the partial flows of the exhaust gas / fluid are constantly redirected and can flow into adjacent wave crests or troughs, particularly in a zigzag pattern.
[0033] Especially with such structures, a so-called CS corrugation, a high surface pressure is regularly present because the contact zones between the films have only a short extent along the axial direction. It is therefore particularly advantageous here to deliberately reduce the prestress in the initial sections so that undesired bonding is avoided as much as possible. In particular, the axial extent of the honeycomb structure, and thus of the at least one film, is between 5 and 1,000 millimeters, preferably less than 200 millimeters.
[0034] In particular, the material thickness of the film is between 20 pm and 2 millimeters, and in particular at most 1.0 or even at most 0.5 millimeters.
[0035] In particular, the wave structure has an amplitude (i.e., a maximum extent of the structured layer in the vertical direction) between 0.5 millimeters and 10 millimeters, especially of at most 5 millimeters.
[0036] In particular, the honeycomb structure has a cell (or channel) density (in the area of the first section) of 200 to 3,000 cpsi (cells per square inch).
[0037] The honeycomb structure is formed by arranging the sheets on top of each other. This can be achieved by using a stack of sheets stacked directly on top of each other, or by folding, wrapping, and / or twisting the stack. Such honeycomb structures are generally known.
[0038] In particular, the first section along the axial direction has a length equal to P / tan(angle of inclination), especially with a deviation of at most 20%, and especially with a deviation of at most 10%. P is the distance between two adjacent wave crests (or troughs) of a film. The quotient "tan(angle of inclination)" is the tangent of the angle of inclination (of the structures or corrugations inclined relative to the axial direction by the angle of inclination). In particular, this definition applies to angles of inclination greater than zero degrees.
[0039] Alternatively or additionally, it is required that in the first section there are at least two contact zones where a (specific) wave crest (or a specific wave trough) of one film contacts a neighboring film (especially in the case of structures running at an angle or at an angle of inclination).
[0040] The respective first and second sections have a length that is at least 2%, in particular at least 5%, preferably at least 8% of the (total) extent of the film or the honeycomb structure in the axial direction (i.e., the distance of a fluid inlet side from a fluid outlet side of the honeycomb structure).
[0041] In particular, the prestress defined for the respective section (and essentially constant) is present over the entire length of the respective section.
[0042] In particular, a first section is arranged at both the fluid inlet and outlet sides, with only a single second section in between. Specifically, the second section connects directly to the respective first section.
[0043] In particular, the honeycomb body or honeycomb structure comprises at most five sections, in particular at most four sections, preferably at most three sections or even only two sections.
[0044] Specifically, only sections with a total of two different prestressing forces are planned. However, at least three sections with three or more different prestressing forces may also be planned.
[0045] In particular, the honeycomb structure contacts the inner circumferential surface of the casing tube in both the first and second sections.
[0046] In particular, the honeycomb structure, preferably the at least one sheet, extends along the axial direction from the fluid inlet side to the fluid outlet side. Specifically, the transition between a first section and a second section is not abrupt, but gradual. In particular, the first inner circumference transitions successively into the second inner circumference, or the structure with the first height transitions successively into the structure with the second height. In particular, this transition is regularly shorter (viewed in the axial direction) than the first section or the second section.
[0047] In particular, the first preload is between 2.5 and 8%, preferably between 2.8 and 5.5%, and the second preload is between zero and 1%, preferably between 0.1 and 0.6%.
[0048] In particular, at least 90% of all (materially bonded) connections of the honeycomb structure, and especially at least 95%, are located in at least one first section.
[0049] In particular, the metallic foil has a ferritic material composition or microstructure. Specifically, the foil contains carbon and chromium as alloying elements.
[0050] The described metallic foils (excluding the varying heights of the structures, which are intended to create different prestresses in the honeycomb structure) and the honeycomb body or honeycomb structure are fundamentally known. Reference is made in this regard to known designs of foils and honeycomb bodies or honeycomb structures.
[0051] The honeycomb structure is primarily intended for exhaust gas aftertreatment. Reference is made to the explanations in the introduction.
[0052] Furthermore, the use of the honeycomb structure or its position in an exhaust system is proposed, for example, in a motor vehicle or a stationary system that has an internal combustion engine with an exhaust system. The exhaust system has at least one catalyst carrier or a particulate separator designed with a honeycomb structure as described herein. The catalyst carrier and / or the particulate separator may have a catalytically active coating.
[0053] The use of indefinite articles (“a”, “an”, “one”, and “ones”), particularly in the patent claims and the description reproducing them, is to be understood as such and not as a numeral. Accordingly, terms or components introduced by these articles are to be understood as occurring at least once and, in particular, may also occur multiple times.
[0054] It should be noted as a precaution that the numerical terms used here ("first", "second", etc.) primarily serve (only) to distinguish between several similar objects, quantities, or processes, and thus do not necessarily dictate any dependency and / or sequence between these objects, quantities, or processes. Should a dependency and / or sequence be required, this is explicitly stated here, or it will be obvious to a person skilled in the art upon studying the specific configuration described. Where a component can occur multiple times ("at least one"), the description of one of these components may apply equally to all or some of the multiple components, but this is not mandatory.
[0055] The invention and its technical context are explained in more detail below with reference to the accompanying figures. It should be noted that the invention is not limited by the exemplary embodiments shown. In particular, it should be noted that the figures, and especially the proportions depicted, are only schematic. They show:
[0056] Fig. 1: a section of a honeycomb structure formed by the foils in a perspective view, partly in section;
[0057] Fig. 2: the section according to Fig. 1 in a view along an axial
[0058] Direction; Fig. 3: a casing tube of a honeycomb structure in a side view in
[0059] Cut;
[0060] Fig. 4: a sheet in a side view;
[0061] Fig. 5: the foil according to Fig. 4 in a perspective view;
[0062] Fig. 6: a cross-section of the foil according to Figs. 4 and 5 in the first section;
[0063] Fig. 7: a cross-section of the foil according to Figs. 4 and 5 in the second section;
[0064] Fig. 8: an example of a honeycomb structure with the foils according to Fig. 4 to
[0065] 7; and
[0066] Fig. 9: a method for producing the film according to Figs. 4 to 7.
[0067] Fig. 1 shows a section of a honeycomb structure 3 formed by the foils 8 and 26 in a perspective view, partly in section. Fig. 2 shows the section from Fig. 1 in a view along an axial direction 6. Fig. 3 shows a casing tube 2 with an indicated honeycomb body 1 with the foils 8 and 26 as shown in Figs. 1 and 2. Figures 1 to 3 are described together below.
[0068] The honeycomb body 1 comprises a casing tube 2 according to Fig. 3 and a honeycomb structure 3 arranged in the casing tube 2 (according to Fig. 1). The casing tube 2 extends between an open first end face 4 and an open second end face 5 along an axial direction 6.
[0069] The honeycomb structure 3 is formed by at least one metallic foil 8 having a structure 7, which is stacked and wound or twisted, thus forming channels 9 through which a fluid can flow. The channels 9 extend from a fluid inlet side 10 located at the first end face 4 to a fluid outlet side 11 located at the second end face 5. The honeycomb structure 3 has several disk-shaped sections 12, 13, which are arranged side by side along the axial direction 6 and each is positioned in the casing tube 2 with a different preload.
[0070] The prestress o is defined as an area excess of a first cross-sectional area Qi 14, which exists in a load-free state, compared to a second cross-sectional area Q215 of the honeycomb structure 3, which is limited by an inner circumference 16 of the casing tube 2, i.e. o = (QT - Q2) / Q2.
[0071] The honeycomb structure 3 is arranged in the first sections 12, which are located at the fluid inlet side 10 and the fluid outlet side 11 and extend along the axial direction 6, with a first prestress in the jacket tube 2, which is higher than a second prestress in the second section 13, which extends between the first sections 12 and connects to each of them.
[0072] The sections 12, 13 are disc-shaped and each have the second cross-sectional area 15 of the casing tube 2 surrounding them in the respective section 12, 13, or extend to the inner circumferential surface 30 of the casing tube 2.
[0073] The outer casing 2 has, in the area of the first sections 12, a first inner circumference 16 designed to generate the first prestress and, in the area of the second section 13, a second inner circumference 17 designed to generate the second prestress, wherein the first inner circumference 16 is smaller than the second inner circumference 17 in each case.
[0074] A second cross-sectional area 15 of the honeycomb structure 3 present in the first section 12 is smaller than a second cross-sectional area 15 present in the second section 13. The inner diameter of the casing tube 3 in the region of the first section 12 is smaller than in the region of the second section 13. The first cross-sectional area 14 of the unloaded honeycomb structure 3 is the same size in the (later) first section 12 and in the second section 13 (i.e., before being arranged in the casing tube 2).
[0075] The honeycomb structure 3 is compressed or prestressed more strongly in the area of the first section 12 by a local constriction of the jacket tube 3 than in the second section 13. This allows a surface pressure in the contact zones 29 to be increased in the first section 12, so that material-bonded connections between the contacting films 8, 26 are preferentially formed there (e.g. by the carbide precipitates).
[0076] In contrast, the honeycomb structure 3 in the area of the second section 13 is prestressed to a lesser extent after arrangement in the jacket tube 2, so that the formation of material-bonded connections is prevented or at least reduced there.
[0077] To produce the honeycomb body 1, a casing tube 2 can be provided, and then the honeycomb structure 3 can be inserted into the casing tube 2 via one of the end faces 4, 5. The cross-section of the casing tube 2 can be reduced either before or after the insertion of the honeycomb structure 3, e.g., in the area of the first section 12, so that a predetermined prestress is applied there.
[0078] The honeycomb structure 3 according to Figures 1 and 2 comprises a stack 21 formed by the film 8 and the further film 26, wherein the corrugation (or the corrugation-formed structure 7) has a plurality of parallel wave troughs 22 and wave crests 23, each extending along a direction 25 at an angle 24 to the axial direction 6 of greater than zero degrees and at most 15 degrees. The stack 21 and the channels 9 are formed by arranging another structured area of the same film 8 (e.g., when it is folded) or—as shown here—by arranging a further structured film 26 (with the same structure 7, but oriented in the opposite direction) on top of the film 8. The further film 26 is structured such that the overlapping wave troughs 22 and wave crests 23 intersect.
[0079] For the foils 8, 26 with intersecting directions 25, angles result between the contacting wave troughs 22 and wave crests 23, which correspond to the sum of the inclination angles 24 of each foil 8, 26.
[0080] Structure 7 of the foil 8 extends over the entire length of the honeycomb structure 3, i.e., between the fluid inlet side 10 and the fluid outlet side 11. The corrugation is formed by elevations (wave crests 23) and depressions (wave troughs 22). Wave crests 23 and wave troughs 22 alternate regularly. The wave crests 23 and wave troughs 22 exhibit a sinusoidal corrugation in cross-section.
[0081] The arrangement of structure 7, or rather the wave crests 23 and wave troughs 22, within the honeycomb body 1 is such that they run obliquely to the axial direction 6. This creates channels 9 for a fluid that do not run parallel to the axial direction 6, but rather obliquely to it. Thus, if an exhaust gas flow or a fluid flow impinges perpendicularly on an end face 4 of the honeycomb body 3 or on a fluid inlet face 10 of the honeycomb structure 3, the exhaust gas / fluid is first divided because it enters the channel openings formed by the wave crests 23 and wave troughs 22 and is then deflected within the honeycomb structure 3. The configuration of structure 7 is such that the wave crests 23 and wave troughs 22 in adjacent areas (viewed in the radial direction 18 with respect to a center point of the cross-sectional area of the honeycomb structure 3) are inclined differently or have a different orientation. For example, if...If a deflection to the right occurs in one area, a deflection to the left occurs in the area further inwards, and vice versa. This alignment or orientation constantly changes when viewed in the radial direction 18. This results in the wave crests 23 and wave troughs 22 not lying on top of each other in a linear fashion at any point in the honeycomb structure 3, but rather intersecting each other and thus essentially forming only point-like contact points or contact zones 29. This results in a structure in which the partial flows of the exhaust gas / fluid are constantly deflected and can flow into adjacent wave crests 23 or wave troughs 22, in a zigzag pattern.
[0082] Especially in such structures 7, a so-called CS corrugation, a high surface pressure is regularly present because the contact zones 29 between the films 8, 26 have only a short extent along the axial direction 6. It is therefore particularly advantageous here to deliberately reduce the prestress in the first sections 12 so that undesired material-bonded connections are avoided as much as possible.
[0083] The first section 12 has a length 27 along the axial direction 6, which corresponds to P / tan(angle of inclination). P is a distance 28 between two adjacent wave crests 23 (or wave troughs 22) of a foil 8, 26 (see Fig. 2). The quotient “tan(angle of inclination)” is the tangent of the angle of inclination 24.
[0084] Alternatively or additionally, it is assumed that in the first section 12 at least two contact zones 29 are present, at which a specific wave crest 23 (or a specific wave trough 22) of one film 8, 26 contacts an adjacently arranged film 8, 26.
[0085] The honeycomb structure 3 contacts the inner circumferential surface 30 of the outer tube 2 in both the first sections 12 and the second section 13.
[0086] The honeycomb structure 3 and the foils 8, 26 extend along the axial direction 6 from the fluid inlet side 10 to the fluid outlet side 11.
[0087] A multitude of contact zones 29 have, for example, material-bonded (soldered) connections. It is also possible to predetermine a subset of the contact zones 29 where a soldered connection is formed or is to be formed. Fig. 4 shows a foil 8 in a side view. Fig. 5 shows the foil 8 according to Fig. 4 in a perspective view. Fig. 6 shows a cross-section of the foil 8 according to Figs. 4 and 5 in the first section 12. Fig. 7 shows a cross-section of the foil 8 according to Figs. 4 and 5 in the second section 13. Figs. 4 to 7 are described together below. Reference is made to the descriptions of Figs. 1 to 3.
[0088] The structure 7 of the film 8 is formed by a corrugation that has a height 19, 20 along a radial direction 18 extending transversely to the axial direction 6, wherein the film 8 has a structure 7 with a first height 19 in the first section 12 and a structure 7 with a second height 20 in the second section 13, the first height 19 being greater than the second height 20. The first cross-sectional area 14 of the honeycomb structure 3 formed by such films 8 is larger in the first section 12 than the first cross-sectional area 14 in the second section 13.
[0089] When such a film 8 is wound up, for example, in the first section 12, with each additional layer, another structure 7 with a first height 19 is arranged on top of the other structures 7 with a first height 19. The same applies to structures 7 with a second height 20 for the second section 13. That is, with each layer of winding, a larger first cross-sectional area 14 is formed in the first section 12 than in the second section 13. The diameter of the honeycomb structure 3 in the first section 12 then corresponds, for example, to the number of windings multiplied by the first height 19, while the diameter of the honeycomb structure 3 in the second section 13 then corresponds to the number of windings multiplied by the smaller second height 20. The same applies to wound films 8, 26 or wound stacks 21 of films 8, 26, but also to stacks 21 of films 8, 26.
[0090] Such a film 8 can be produced by, for example, a two-stage forming process. In the first stage, a uniform structure 7 is created across the entire film 8. In the second stage, sections 12, 13 of the film 8 can then be further formed. In the second stage, at least the height 19, 20 of the structure 7 can be further increased, thus forming a first section 12. As shown in Figures 6 and 7, the shape of the channels 9 or the corrugation of the film 8 (here from sinusoidal to zigzag) can also be changed. The distance 28 between two adjacent wave crests 23 or wave troughs 22 remains unchanged. The cross-sectional area of the respective channel 9 formed by the structure 7 of the film 8 in the honeycomb structure 3 is changed so that this cross-sectional area in the first section 12 is larger than the cross-sectional area of the channel 9 in the first section 12.
[0091] The transition between the first section 12 and the second section 13 is not abrupt, but gradual. The first inner circumference 16 transitions successively into the second inner circumference 17, or rather, the structure 7 with the first height 19 transitions successively into the structure 7 with the second height 20. This transition, however, is regularly shorter (viewed in the axial direction 6) than the first section 12 or the second section 13.
[0092] The honeycomb body 1 has at least one ribbon-shaped film 8, 26 with a corrugated structure 7. Figure 8 shows that at least partially, or at least on one side of the honeycomb structure 3, between the films 8, 26 with structure 7, a smooth film without a corrugated structure is arranged between each of the films 8, 26 with structure 7. However, this is not strictly necessary, especially with the CS corrugation shown.
[0093] Fig. 9 shows the process for producing the film 8 with a rolling device 31 in a side view. Reference is made to the descriptions of Figs. 1 to 8.
[0094] The film 8 is produced by a two-stage forming process. The rolling device 31 used for this purpose comprises two pairs of rollers 32, 33. Each pair of rollers 32, 33 comprises two rollers that mesh with each other, thereby conveying the film 8 along the feed direction 34. The first pair of rollers 32 forms the first stage, the second pair of rollers 33 the second stage. In the first stage, a uniform structure 7 is created on the entire film 8, starting from a smooth / flat / unstructured film 8. In the second stage, sections 12, 13 of the film 8 can then be further formed. In the second stage, at least the height 19, 20 of the structure 7 can be further increased, thus forming a first section 12. As shown in Figures 6 and 7, the shape of the channels 9 or the corrugation of the film 8 (here from sinusoidal to zigzag) can also be changed.The distance 28 between two adjacent wave crests 23 or wave troughs 22 remains unchanged. The cross-sectional area of the respective channel 9 formed by the structure 7 of the film 8 in the honeycomb body 3 is changed, such that this cross-sectional area in the first section 12 is larger than the cross-sectional area of the channel 9 in the second section 12.
[0095] Reference symbol list
[0096] 1 honeycomb body
[0097] 2. Sheathing tube
[0098] 3 honeycomb structure
[0099] 4 first front
[0100] 5 second front
[0101] 6 axial direction
[0102] 7 Structure
[0103] Slide 8
[0104] 9-channel
[0105] 10 Fluid inlet side
[0106] 11 Fluid outlet side
[0107] 12 first section
[0108] 13 second section
[0109] 14 first cross-sectional area Q-,
[0110] 15 second cross-sectional area Q2
[0111] 16 first inner circumference
[0112] 17 second inner circumference
[0113] 18 radial direction
[0114] 19 first height
[0115] 20 second height
[0116] 21 stacks
[0117] 22 troughs
[0118] 23 wave crest
[0119] 24 tilt angles
[0120] 25 Direction of travel
[0121] 26 more slides
[0122] 27 Length
[0123] 28 distance
[0124] 29 Contact zone
[0125] 30 Inner perimeter area
[0126] 31 Rolling device first pair of rolls second pair of rolls feed direction
Claims
Patent claims 1. Honeycomb body (1), comprising at least a casing tube (2) and a honeycomb structure (3) arranged in the casing tube (2); wherein the casing tube (2) extends between an open first end face (4) and an open second end face (5) along an axial direction (6); wherein the honeycomb structure (3) is formed by at least one metallic foil (8) having a structure (7), which is stacked, wound, or twisted at least one upon the other and thus forms channels (9) through which a fluid can flow, extending from a fluid inlet side (10) arranged at the first end face (4) to a fluid outlet side (11) arranged at the second end face (5); wherein the honeycomb structure (3) has several disk-shaped sections (12, 13) arranged side by side along the axial direction (6) and each arranged with a different preload in the casing tube (2);wherein the prestress o is defined as an area excess of a first cross-sectional area Q-, (14) of the honeycomb structure (3), which exists in a load-free state, compared to a second cross-sectional area Q2(15), which is bounded by an inner circumference (16, 17) of the casing tube (3), i.e. o = (QT - Q2) / Q2; wherein the honeycomb structure (3) is arranged at least in a first section (12) in the casing tube (3), which is arranged from the fluid inlet side (10) and fluid outlet side (11) and extends along the axial direction (6), with a first prestress in the casing tube (3) that is higher than a second prestress in a second section (13) adjoining the first section (12).
2. Honeycomb body (1) according to claim 1, wherein the casing tube (2) has in the area of the first section (12) a first inner circumference (16) designed to generate the first prestress and in the area of the second section (13) a second inner circumference (17) designed to generate the second prestress, wherein the first inner circumference (16) is smaller than the second inner circumference (17).
3. Honeycomb body (1) according to one of the preceding claims, wherein the structure (7) of the at least one sheet (8) is a corrugation having a height (19, 20) along a radial direction (18) extending transversely to the axial direction (6), wherein the at least one sheet (8) has a structure (7) with a first height (19) in the first section (12) and a structure (7) with a second height (20) in the second section (13), wherein the first height (19) is greater than the second height (20); wherein the first cross-sectional area (14) in the first section (12) is larger than the first cross-sectional area (14) in the second section (13).
4. Honeycomb body (1) according to claim 3, wherein the honeycomb structure (3) is formed exclusively by at least one film (8) which has in the first section (12) a structure (7) with a first height (19) and in the second section (13) a structure (7) with a second height (20).
5. Honeycomb body (1) according to one of the preceding claims 3 and 4, wherein the honeycomb structure (3) comprises at least one stack (21) formed at least by the film (8), wherein the corrugation has a plurality of parallel wave troughs (22) and wave crests (23), each extending at an angle (24) to the axial direction (6) of greater than zero degrees and at most 15 degrees along a direction (25); wherein the stack (21) and the channels (9) are formed by arranging another structured area of the same film (8) or by arranging a further structured film (26) on the film (8); wherein the other area of the film (8) or the further film (26) is structured such that the overlapping wave troughs (22) and wave crests (23) intersect.
6. Honeycomb body (1) according to claim 5, wherein • the first section (12) along the axial direction (6) has a length (27) which P / tan(angle of inclination) with a deviation of at most 20%, where P is a distance (28) between two adjacent wave crests (23); or • in the first section (12) at least two contact zones (29) are present, at which a wave crest (23) of one film (8) contacts an adjacent film (8, 26).
7. Honeycomb body (1) according to one of the preceding claims, wherein the first section (12) is arranged at the fluid inlet side (10) and at the fluid outlet side (11), and only a single second section (13) is arranged between them.
8. Honeycomb body (1) according to one of the preceding claims, wherein the first prestress is between 2.5 and 8% and the second prestress is between zero and 1%.