Title of Invention

AN IMPROVED HONEYCOMB BODY, IN PARTICULAR A CATALYTIC CONVERTER CARRIER BODY

Abstract

The invention relates to a honeycomb body (1). in particular a catalytic converter carrier body, with stacked and/or wound sheet layers (17:18) of which at least a portion are structured sheet layers (18), thus forming passages through which a fluid can flow, wherein a portion of the sheet layers (17:18) is of a first thickness (a) and a portion of the sheet layers (17:18) is of a second thickness (b) which is greater than the first thickness (a) , and wherein the honeycomb body (1:21) contains in its interior a (17:18) o1 the second thickness (b ) , of which at least one is a structured sheet layer (18) and which at least in a location-wise manner are connected together by a procedure involving the intimate lodning of materials.

Full Text

1A The present invention concerns an improved honeycomb body, in particular a catalytic converter carrier body Honeycomb bodies of that kind are used for example for the catalytic conversion of exhaust gases of an internal combustion engine EP 0 436 533 B1 discloses honeycomb bodies which contain a stack, twisted in mutually oppositely directions, of at least partially structured metal sheets in a tubular casing One or more of the sheet layers of the stack is of greater thickness than the other layers, wherein said layer or layers comprises or comprise thicker sheet or a plurality of thin sheets which bear closely against each other The thicker and thimer sheet layers form walls of passages, through which an exhaust gas stream can flow The sheet layers are connected to the tubular casing, at least in- portions thereof, by a procedure involving intimate joining of the materials involved The thicker sheet layers cannot be easily torn away at the tubular casing, by virtue of their greater mechanical strength In addition they can also hold fast the thinner sheet layers which are adjacent thereto so that they also cannot be torn away from the tubular casing or however are held fast by the thick sjieet layer at least in spite of being torn away at the tubular casing The individual metal sheet layers of the stack can be soldered together, preferably at one of the two ends of the honeycomb body The above-described configuration, by virtue of the thick sheet layers, affords a wall structure for stabilizing the honeycomb body : 1B : From WO 96/21503 it is also already known, to produce a reinforcing structure in a honeycomb body made from at least partly structured layers of metal sheets having equal thicknesses by joining at least one flat and one structured flayer at their contacting lines. This stabilizes mainly honeycomb bodies made from sheet metal layers which are otnerwise not Joined to each other. In recent years the development of new honeycomb bodies has been along the lines of reducing thermal capacity. With a lower thermal capacity it is possible to achieve in particular Improved cold start performance when using the honeycomb bodies in exhaust gas catalytic converters. The ignition temperature as from which the catalytic procedure begins is achieved earlier. 2 Besides thermal capacity the pressure drop which occurs in a gas flow through the honeycomb body also plays a part in development The pressure drop should be as low as possible Both development aims, namely a low termal capacity and a low-pressure _drop. can be achieved by means of thin passage wa11_s However the passage walls cannot be made of just any arbitrarily thin dimension as the wall structure otherwise becomes unstable and is damaged under thermal and/or me,cham cal loadings The object of the present invention is to provide a honeycomb body having thin passage walls, which enjoys a high level of stability According to the invention that object is attained by a honeycomb body having the features of claim 1 Advantageous developments are the subject-matter of the appendant claims A honeycomb body according to the invention has sheet metal layers of a first thickness and sheet metal layers of a second thickness, wherein the second thickness is greater than the first thickness In its interior the honeycomb body contains a lattice-like structure which is formed from at least two sheet layers of the second thickness, Of those sheet layers at least one is a structured sheet layer The at least two sheet layers are connected together at least in a location-wise manner by a procedure involving intimate joining of materials, preferably by being soldered together The reference to "a" thickness of a sheet layer denotes the mean thickness of the sheet material, while the local thickness can vary by some percent of the mean thickness The connecting locations are point-like, line-like or surface-like Connections involving intimate joining of the materials involved exist preferably over the entire length of the lattice-like structure, that is to say in the direction of flow through the passages, and transversely with respect to the direction of flow through the passages A crucial consideration in terms of the stability of the honeycomb body is adequate inherent stability of the lattice-like structure The connections involving intimate joining of the materials are therefore preferably continuous or disposed at suitable spacings Depending on the configuration of the honeycomb body and the purpose of use however a connection involving intimate joining of the material involved is under some circumstances also adequate at the ends of the passages, that is to say at the ends of the honeycomb body An advantage of the invention is that honeycomb bodies with thin walls can be of a stable structure By virtue thereof it is possible for example to achieve a high cell density, that is to say a large number of passages per unit area in the cross-section of the honeycomb body, without having to tolerate the disadvantage of a high pressure drop A high cell density has a favourable effect on the catalytic conversion of exhaust gases as it is 3 possible to achieve a large catalytically active surface area per unit volume of the honeycomb body In cold start phases or re-starting phases of an internal combustion engine with an exhaust gas catalytic converter it is important for the catalytic converter to reach the ignition temperature as quickly as possible^ Thin walls permit that to occur, by virtue of their low thermal capacity The crucial consideration is that the ignition temperature is reached quickly, at least locally at the thin walls There is however no need for it to be attained approximately simultaneously everywhere in the catalytic converter as the chemical reactions which take place after the ignition temperature is attained are exothermic The zones in which the ignition temperature is reached or exceeded therefore rapidly spread The use of honeycomb bodies according to the invention results in early initiation of the catalytic procedure in exhaust gas catalytic converters With the sheet layers of the first and second thicknesses receiving an approximately uniform incident flow of hot exhaust gas the catalytic procedure begins at the (thinner)_sheet layers of the first thickness and rapidly spreads to the sheet layers of the second thickness In comparison with honeycomb bodies of the same thermal capacity in respect of the sheet layers but only with sheets-layers of one thickness, the catalytic procedure begins more quickly /However it still begins more quickly even when the thermal capacity of the sheet layers of the honeycomb body according to the invention is greater, as long as there are thinner sheet layers The connection by means of intimate joining of the-materials involved is preferably effected after the step of stacking and/or winding or coiling the sheet layers Otherwise the sheet layers of the first thickness could be damaged, for example torn through, by the sheet layers of the second thickness or the lattice-like structure The sheet layers are preferably soldered together For soldering the lattice-like structure it is possible to consider all known soldering procedures in which finishing of the soldering operation is possible after stacking and/or winding or coiling of the sheet layers In particular it is also possible to use different soldering processes for soldering the lattice-like structure and soldering the other sheet layers For example solder foils or solder wires can be wound in between the sheet layers of the lattice-like structure In that way solder joins can also be produced in the interior of the honeycomb body, within the lattice-like structure, while the other sheet layers are for example soldered together and to the lattice-like structure only at the ends of the honeycomb body. In regard to the honeycomb body according to the invention there are design configurations with a plurality of lattice-like structures which are 4 preferably uniformly distributed over the stack or winding of the sheet layers A honeycomb body according to the invention is for example constructed with partially structured sheets, as described in EP 0 436 533 The passage walls formed by sheet layers are preferably of a thickness which remains approximately the same over the axial length of the honeycomb body There are however also embodiments in which the reinforced lattice-like wall structure extends only over one or more portions of the axial length of the honeycomb body That can be achieved for example by portion-wise reinforcement of the sheet layers with shorter sheet layers In a further embodiment with structured sheet layers the structures have line-like raised portions or ridges with which they contact adjacent sheet layers At least two adjacent sheet layers which are structured in that way are in mutual contact with raised portions or ridges which extend in mutually crossed relationship so that they only touch each other in approximately point-wise manner Those sheet layers are sheet layers of the second thickness and at a plurality of the contact points are connected together by a procedure using intimate joining of the materials involved, preferably by being soldered together, thus affording a three-dimensional lattice-like wall structure which stabilizes the honeycomb body An advantage of the honeycomb body according to the invention that forces which act on the lattice-like wall structure in directions in which, at any event at the locations at which the forces act, no sheet layers of the second thickness extend, can also be carried away by way of the lattice-like wall structure A further advantage of the honeycomb body according to the invention is a_favourable vibration-Characteristic Due to its stable construction the lattice-like structure is insensitive to vibration In addition however it also reduces the vibration lengths, perpendicularly to the axial length of the honeycomb body, of the regions with thinner sheet layers The vibration lengths can be matched to a given purpose of use of the honeycomb body Care is to be taken to ensure that no resonance vibrations of the honeycomb structure are induced In a development of the honeycomb body according to the invention a larger part of the passage wall surfaces in the interior of the honeycomb body is formed by the sheet layers of the first thickness than by the sheet layers of the second thickness 'with the first thickness being at least 20% less than the second thickness In an embodiment of the honeycomb body the first thickness is of a value of between 15 µm and 50 µm. preferably about 20 - 30 µm In an advantageous development of the honeycomb body it has a tubular 5 casing, in the interior of which the sheet layers are arranged, wherein the lattice-like structure has a plurality of casing connecting locations at each of which at least a respective one of its sheet metal layers of the second thickness is connected to the tubular casing That arrangement can provide a stable unit comprising the tubular casing and the lattice-like structure An advantageous development thereof is one in which two casing connecting locations are connected together by the lattice-like structure An embodiment of the honeycomb body according to the invention provides for the formation of passages through which a fluid can flow and which extend in substantially parallel relationship and which are approximately closed off relative to each other, with stacked and/or wound or coiled sheet layers, of which at least a portion are structured sheet layers, wherein the arrangement has sheet layers of the second thickness, with which the lattice-like structure is formed The sheet layers of the second thickness are connected by a procedure using intimate joining of the materials involved, preferably soldering, at contact locations, to at least one other sheet layer of the second thickness, and/or there blend into another sheet layer of the second thickness In other words, the sheet layers which blend into each other are parts of the same sheet This embodiment includes honeycomb bodies which are wound in a'spiral configuration, honeycomb bodies which are constructed in an S-shape and other embodiments of previously known honeycomb bodies with stacked and/or wound sheet layers In certain alternative forms of this embodiment the lattice-like structure is formed from one or more sheets of the first thickness, which are reinforced in a portion-wise manner by sheet strips which are connected thereto by a procedure using intimate joining of the materials involved Those portions form the passage walls of the second thickness In a further embodiment the lattice-like wall structure has a plurality of adjacent sheet layers of the second thickness, which have together, in respective pairs, a plurality of connecting locations, at least one of the sheet layers being a structured sheet layer In a development the lattice-like structure extends with two or more sheet layers, as viewed in the cross-section of the honeycomb body, approximately along a line extending in the manner of a spiral arm, preferably approximately along an involute In still another development the honeycomb body has in cross-section a plurality of lattice-structured spiral arms The spiral arms are connected together in the region of a spiral core, wherein the spiral arms preferably include approximately equal angles between them, at the spiral core In that respect the angle is to be measured between the lines connecting the centre of the spiral core to the points of attachment of the spiral arms to the spiral core The spiral arms, the spiral core and 6 optionally a tubular casing connected to the outer ends of the spiral arms form a stable framework, between which the passage walls of the first thickness are arranged In an alternative form of this development the inner ends of the spiral arms are not connected together by way of a spiral core, but are directly connected to each other In that situation the spiral arms divide each imaginary circle with a centre point in the proximity of the connecting region of the spiral arms, the peripheral line of which is cut by the spiral arms, into portions of approximately equal size In a further embodiment the honeycomb body is of a structure similar to that described in EP 0 436 533 B1, with a stack of sheet layers, which stack is twisted in mutually opposite directions, wherein the lattice-like structure is disposed approximately at the centre of the stack In a development the stack includes further lattice-like structures, preferably such that an equal number of sheet layers are disposed between the lattice-like structures Embodiments of the honeycomb body according to the invention are described with reference to the drawing These embodiments are examples, to which the invention however is not limited In the individual Figures of the drawings Figure 1 is a view in cross-section of a honeycomb body with a stack, which is twisted in mutually opposite directions, of partially structured sheet layers. Figure 2 is a view in cross-section of a honeycomb body with spirally wound sheet layers, and Figures 3 to 5 show lattice-like structures with adjacent sheet layers in profile figure 1 shows a honeycomb body 1 according to the invention with a stack, twisted in mutually opposite directions, of mutually alternate smooth sheet metals layers 17 and structured sheet metal layers 18 Approximately at its centre the stack includes a lattice-like structure 4 with a plurality of connecting locations 5. which is made up of two adjacent sheet layers 3 Those sheet layers 3 are sheet layers of the second thickness b The other, oppositely twisted sheet layers are sheet layers 2 of the first thickness a The stack is arranged in the interior of a tubular casing 6. wherein the lattice-like structure 4 is soldered to the tubular casing 6 at casing connecting locations 8 The solder connection or connections between the tubular casing 6 and the lattice-like wall structure 4 preferably extends or extend only over a portion or portions of the axial length of the tubular casing (not shown in the drawing) in order to permit different variations in length, due to thermal causes, of the tubular casing 6 and the wall structure The sheet layers 2. 3 of the first thickness a and the second thickness b can be soldered together at some of or all their contact locations Figure 2 shows a honeycomb body 21 with wound or coiled sheet layers 2. 7 3 which extend in cross-section approximately along involutes Disposed approximately on the centre axis of the honeycomb body 21 is a spiral core 7 in the form of a hollow cylinder to which the sheet layers 2. 3 are connected The honeycomb body 21 has two lattice-like wall structures 14 which in cross-section follow spiral arm-like lines They are each made up of three sheet layers 3, two being smooth and therebetween a structured layer, and they are arranged approximately symmetrically relative to each other with respect to the centre axis of the honeycomb body 21 The angle ##a. that they include between them at the spiral core 7 is therefore approximately 180° Figures 3 to 5 each show a portion of a lattice-like structure 4 having at least one smooth sheet layer 17 and a structured sheet layer 18. which are both of the second thickness, and have a plurality of connecting locations 5. The lattice-like structure 4 in Figure 3 has triangular bordered passages 9. The passages 9 in Figure 4 are approximately triangular in cross-section Indicated by way the example of a passage 9. with two broken lines, are the straight lines along which the corrugated sheet layer 18 extends between the two smooth sheet layers 17 Of the smooth layers 17 at least one is of the second thickness The sheet layers 17. 18 of the second thickness are connected together by a procedure involving intimate joining of the materials, at a plurality of their contact locations If the second smooth sheet layer 17 in Figure 4 is a sheet layer of the first thickness, it is preferably also connected to the structured sheet layer 18 by the intimate joining method, at a plurality of its contact locations with respect to the structured sheet layer 18 Figure 5 shows passages 9 of trapezoidal cross-sectional area Broken lines indicate the direction along which there extend the lattice wall portions of the structured sheet layer 18. which connect the two smooth sheet layers 17 together The two broken lines intersect outside the lattice cell 9 with an internal angle 6 Figure 5 also shows the opposite angle ##B" which is equal to the angle ##B The broken lines make it possible to see the lattice construction which is basically of triangular cross-section and which imparts its stability to the structure As the examples show, embodiments of the honeycomb body according to the invention are of a similar structure to previously known honeycomb bodies With just minor modifications they can be produced by means of the same processes as the previously known honeycomb bodies Honeycomb bodies with lattice-like structures can therefore be produced at approximately the same cost but they permit the use of thinner sheet layers or they have a higher degree of stability than previously known honeycomb bodies 8 List of references 1 honeycomb body 2 sheet layer of the first thickness 3 sheet layer of the second thickness 4 lattice-like structure 5 connecting location 6 tubular casing 7 spiral core 8 casing connecting location 9 passage 14 lattice-like structure with three sheet layers 17 smooth sheet layer 18 structured sheet layer 21 honeycomb body with involute lattice structures a first thickness b second thickness ##a angle B internal angle ##8' opposite angle, corresponds to internal angle 9. We Claim 1. An improved honey comb body (1,21) in particular a catalytic metal converter carrier body, comprising ^sheet layers (17, 18) being at least one of stacked and at least one of wound metal sheet layers, at least a portion of said stacked and wound.sheet layers ( 17, 18) consisting of metal a structured^sheet layers (18) having passage wall surfaces such that a passages (9) for flowing a fluid being formed, some of the metal sheet layers (17,18) comprising a metal sheet layer (2) of a first thickness (a) and others of said metal sheet layers ( 17, 18) comprising a metal sheet layer (3) of a second thickness (b) being greater than said first thickness (a), characterized in that a lattice-like structure (4, 14) being formed in an interior of said honeycomb body (1,21) from at least two of said metal sheet layers (17, 18) of said second thickness (b) of which at least one being a structured metal sheet layer (18), and in that said at least two metal sheet layers (17, 18) being connected together at least in a location-wise manner by a procedure using intimate joining of materials involved, a larger portion of said passage wall surfaces in said interior being formed by said metal sheet layers (2) of said first thickness (a) than by said^sheet layers (3) of said second thickness (b), said first thickness (a) being between 15 µm to 50 µm. 2. A honeycomb body as claimed in claim 1, wherein said second thickness (b) is at least 20% greater than said first thickness (a). Contd.... 10 3. A honeycomb body as claimed in one of claims 1 to 2 comprising tubular casing (6), in the interior of which the sheet layers ( 17:18) are arranged, and wherein said the lattice-like structure (4:14) has a plurality of casing connecting locations (8), at each of which at least a metal respective one of its^sheet layers (17:18) of the second thickness (b) is connected to the tubular casing (6). 4. A honeycomb body as claimed in claim 3, wherein casing connecting locations (8) are connected together by the lattice-like structure (4:14). 5. A honeycomb body as claimed in one of claims 1 to 4, wherein said m-tf-4 sheet layer (3) of the second thickness (b) is connected by a procedure using intimate joining of the materials of an adjacent stacked of said metal wound^sheet layer (2) of the first thickness (a). 6. A honeycomb body as claimed in one of claims 1 to 5, wherein at least one structured metal sheet layer (18) of the lattice-like structure (4) is a corrugated sheet layer which at least at a portion of the corrugation apexes is connected by a procedure involving the intimate joining of materials to an adjacent un-structured metal sheet layer (17) of the second thickness (b). 7. A honeycomb body as claimed in one of claims 1 to 6, wherein the lattice-like wall structure (14) extends in cross-section along a line extending in the manner of a spiral arm, preferably along an involute. Contd 11 8. A honeycomb body (21) as claimed in claims 7, comprising a plurality of lattice-structured spiral arms (14) being connected together in the region of a spiral core (7), said spiral arms (14) being disposed at angles (a) between them at the spiral core (7). 9. A honeycomb body as claimed in one of claims 1 to 6, comprising a stack twisted in opposite directions of the metal sheet layers ( 17:18), said lattice-like wall structure (4) being disposed at the center of the stack.. Dated this 28th day of January 1998 The invention relates to a honeycomb body (1). in particular a catalytic converter carrier body, with stacked and/or wound sheet layers (17:18) of which at least a portion are structured sheet layers (18), thus forming passages through which a fluid can flow, wherein a portion of the sheet layers (17:18) is of a first thickness (a) and a portion of the sheet layers (17:18) is of a second thickness (b) which is greater than the first thickness (a) , and wherein the honeycomb body (1:21) contains in its interior a (17:18) o1 the second thickness (b ) , of which at least one is a structured sheet layer (18) and which at least in a location-wise manner are connected together by a procedure involving the intimate lodning of materials.

Documents:

00142-cal-1998-abstract.pdf

00142-cal-1998-claims.pdf

00142-cal-1998-correspondence.pdf

00142-cal-1998-description(complete).pdf

00142-cal-1998-drawings.pdf

00142-cal-1998-form-1.pdf

00142-cal-1998-form-2.pdf

00142-cal-1998-form-3.pdf

00142-cal-1998-form-5.pdf

00142-cal-1998-pa.pdf

00142-cal-1998-priority document.pdf

142-cal-1998-granted-abstract.pdf

142-cal-1998-granted-acceptance publication.pdf

142-cal-1998-granted-claims.pdf

142-cal-1998-granted-correspondence.pdf

142-cal-1998-granted-description (complete).pdf

142-cal-1998-granted-drawings.pdf

142-cal-1998-granted-examination report.pdf

142-cal-1998-granted-form 1.pdf

142-cal-1998-granted-form 2.pdf

142-cal-1998-granted-form 6.pdf

142-cal-1998-granted-letter patent.pdf

142-cal-1998-granted-others.pdf

142-cal-1998-granted-pa.pdf

142-cal-1998-granted-priority document.pdf

142-cal-1998-granted-reply to examination report.pdf

142-cal-1998-granted-specification.pdf

142-cal-1998-granted-translated copy of priority document.pdf