Title of Invention

A CATALYTIC CONVERTER AND A PROCESS FOR PRODUCTING SUCH A CATALYTIC CONVERTER

Abstract

This invention relates to a catalytic converter [1;21,22,23,24.2S;3A,37, ) with a housing (3) for an exahust gas system (17) of an internal combustion engine (16), in particular a Small engine, wherein the catalytic converter .(1;21,22,23,24,25;36,37) has at least one structured sheet (2;13) which is provided with a catalytically active material and which is wound and which forms passages (5) through which exhaust gas cart flow and which at least partially bears against the housing (3), wherein closed passages (5) are formed by the structuring of th« sheet (2,13) and the housing (3) or a sheet of a layer having a smooth and a structured sheet, sa that, as considered over a cross-section of the housing (3) a cross-sectional area which is bordered in by said closed passages (5) constitutes at least half of the total cross-sectional area of the housing (3), wherein the catalytic converter (1;21,22,23,24,25;36,37) has atmost two layers (11) . The structured sheet (49) is wound on incl ined around an at least partially curved elongate body (50),

Full Text

- 1A - The present invention concerns a catalytic converter in a housing for an exhaust gas system of an internal combustion engine, in particular a small engine, wherein the catalytic converter has at least one structured metal sheet which is provided with a catalytically active materia1 and which is wound or twisted, which is formed with passages through which exhaust gas can flow, and which at least partially bears against the housing. The invention also concerns a silencer or muffler for an exhaust gas system of an internal combustion engine and a process for the production of a catalytic converter carrier _body which is arranged in an exhaust gas system of an internal combustion engine, in particular in a silencer or muffler of a small engine. It is known for catalytic converters for exhaust gas systems of an internal combustion engine to be in the form of a honeycomb body. The honeycomb bodies are produced from sheet metal layers which are stacked or wound or twisted together. Other honeycomb bodies in turn comprise sintered or extruded material. Those catalytic converters are intended to ensure that the convertible gases that still remain in the exhaust gas are further converted. A large number of ever increasingly strict exhaust gas requirements, in particular in relation to motor vehicles, means that in the meantime the catalytic converters are of such a design configuration that they ensure almost complete conversion, even when the catalytic converter is in use over a prolonged period of time. The development in the catalytic converter art is in particular along the lines of maximising the catalytically active surface area. Therefore in particular honeycomb bodies which have a large number of passages over their cross-section are used. Besides that possibility of increasing the surface area involved however the length and volume of the catalytic converter and therewith its cross-section are also increased. That however requires a large amount of space to be available for 2 the catalytic converter in the exhaust gas system. In addition, with the catalytic converter being of an increasing size, the working processes for the production thereof become more expensive. In addition, in relation to large catalytic converters, particular attention must be paid to the durability thereof in relation to mechanical and thermal changes in operation, which necessitates a particular mounting arrangement. Set out hereinafter are various design configurations of catalytic converters, to the features of which the present invention refers in respect of the arrangement and form of the catalytic converter. GB 2 231 283 discloses a honeycomb body which has one layer. That layer is formed from a flat metal sheet and a structured metal sheet and ilTthen shapecHrTa spiral to form a multi-layer-catalytic. It has an internal cylindrical free cross-section, the size of which is dependent on the outside diameter of the honeycomb body. The large number of mutually stabilising layers which bear against each other is intended to ensure adequate stiffness for the honeycomb body constructed in that way. DE 37 15 040 discloses another catalytic converter which comprises a strip with non-cutting stampings therein. Those stamping are intended to increase the surface area involved. EP 0 473 081 discloses mounting a catalytic converter in the bend of a motorcycle exhaust gas system.__An aPertured plate is used as the catalytic converter. The plate can be straight or also round. DE 24 36 559 in turn discloses a catalytic converter which is disposed directly in a bend of an internal combustion engine. The bend itself is in the form of a catalytic converter. Besides a catalytic coating on the inside wall of the bend, it is additionally possible to arrange catalytic shaped portions, in particular in screw form. JP 61 61 940 discloses a catalytic converter which is made up of smooth and corrugated metal foils. Arranged upstream of that full catalytic converter is a further catalytic converter which is said to be heatable. US No. 4 195 063 in turn discloses a main catalytic converter with an additional, upstream-disposed catalytic converter. The catalytic converter comprises primarily two catalytically coated mesh arrangements which are each held between two mesh carriers. The catalytic converter can be arranged in the bend, but also in a conical configuration. JP 61 096 120 discloses two tubes which are mounted in the proximity of an engine block in a curved configuration. The interior of the two tubes has holes. A catalytically active layer is arranged between those two tubes. A particularly preferred area of use of a catalytic converter according to the invention is in relation to small engines. The term small engines is used hereinafter to denote engines with a cubic capacity of less than 250 cc. Such engines are used in particular in lawnmowers. motor-driven saws, transportable power generators, two-wheelers and similar uses. In the case 3 of motor-driven saws, lawnmowers and other garden equipment the person operating the apparatus is often disposed over a prolonged period of time directly in the exhaust gas region of the small engine, and for that reason catalytic exhaust gas cleaning is particularly important there. Attention is also directed to DE 38 29 668 in which the catalytic converter, in a small engine, is used in a partitioning wall which extends approximately perpendicularly to the through-flow direction. EP 0 470 113 also discloses an arrangement of the catalytic converter, in which it is arranged with a spacing at all sides in an exhaust gas silencer or muffler for two-stroke engines. EP 0 049 489 also discloses a process for the production of a carrier matrix for an exhaust gas catalytic converter. The features disclosed in those three documents can also be applied to this invention. An object of the present invention is now that of providing a catalytic converter-in a housing for an exhaust gas system of an internal combustion engine, preferably for a small engine, which can be produced in a small number of working steps, which is extremely compact, and which nonetheless makes available a sufficient catalytically active surface area so that limit values which are prescribed by statute in respect of the exhaust gas characteristics of an internal combustion engine are observed. A further object of the invention is to provide a housing for the catalytic converter, which does not nullify again the space gained by virtue of the compact catalytic converter. Another object of the invention is to provide a process for the production of a compact catalytic converter carrier body, which ensures continuous production thereof while avoiding a high level of production expenditure. That object is attained by a catalytic converter having the features of claim 1 and a process having the features of claim 28. Further advantageous configurations and features are recited in the appendant claims. A catalytic converter in a housing for an exhaust gas system of an internal combustion engine, in particular a small engine, has at least one structured metal sheet provided with a catalytically active material. The sheet is twisted or wound, it forms passages through which exhaust gas can flow, and it at least partially bears against the housing. The sheet is of such a structuring that, as considered over a cross-section of the housing, the cross-sectional area which is enclosed or bordered by closed passages constitutes at least half of the total cross-section of the housing, with the catalytic converter having at most two layers. Restricting the catalytic converter to a maximum of two layers makes it possible to achieve an extremely compact catalytic converter which requires a small amount of space. For that purpose it is desirable for the structuring of the sheet to be such, in terms of utilisation of space, that, besides the passage effect of the catalytic converter, there is also sufficient catalytically active surface area 4 available. The use of a maximum of two layers also facilitates heating of the catalytic converter to its useful or operating temperature as it involves less mass to be heated than other catalytic converters of an expensive and complicated construction. In addition the limitation to a maximum of two layers has proven to be advantageous in order to impart to the catalytic converter, besides flexibility, also a high level of stability and rigidity in respect of shape. The catalytic converter affords an at least satisfactory catalytic conversion effect for the exhaust gases, for the preferred uses in the small-engine sector. An improvement in catalytic conversion is achieved if the bordered cross-sectional area constitutes at least two-thirds of the total cross-section of the housing. If the sheet provided with catalytically active material is twisted or wound in such a way that the structuring comes to lie in mutually opposite relationship, that provides that the enclosed cross-sectional area defined by the passages is disposed in a region around the centre point of the catalytic converter while the centre point is arranged within a remaining area which is not completely provided with passages. That can be achieved for flattened cross-sectional regions of the catalytic converter, as well as round, oval or polygonal catalytic converters. Concentration of the bordered cross-sectional area around the centre point makes it possible for the outside passage surfaces which face towards the centre point also to be fully acted upon by exhaust gas. In addition the structuring of the maximum of two layers can' then be particularly advantageously such that the flow resistance in relation to the passages formed is no greater than that of the cross-section which does not completely involve passages. An embodiment of the catalytic converter provides that the mutually oppositely disposed structurings are intertwined or interlaced without touching each other. In that way a quasi-passage-like geometry is imparted to the area which remains free. The mutually oppositely disposed structuring makes it possible for the bordered cross-sectional area to make up at least three-quarters of the total cross-sectional area of the housing. It is precisely in connection with small implements and apparatuses which under some circumstances have to be moved manually that it is important for them to be of small dimensions and low weight, from the point of view of construction thereof. The catalytic converter can contribute thereto by having a stabilising reinforcement. The reinforcement ensures that the catalytic converter enjoys its rigicity in respect of shape without excessively limiting it in regard to its elasticity. The stabilising reinforcement can also be so designed that it performs a load-bearing function for the small implement or apparatus. By virtue of that arrangement the catalytic converter can be fully integrated into same. The housing and the 5 catalytic converter are then in a position of also being incorporated in the detailing and interpretation of the torsional stiffness and structural engineering involved. A catalytic converter which is particularly capable of resisting impacts, vibration and jarring is afforded by each passage-forming sheet of the catalytic converter bearing against a reinforcement. The resistance in this respect can be further increased by the passage-forming sheet which has a top side and an underside bearing respectively with the top side and the underside against a reinforcement. Another possibility of producing a catalytic converter having a high level of stability in respect of shape but also a high degree of elasticity involves constructing a layer thereof with an unstructured sheet and a structured sheet. It can be combined with the means for stabilising reinforcement. A preferred embodiment of a catalytic converter has an unstructured sheet with a top side and an underside, wherein a respective structured sheet is arranged at each of the top side and the underside respectively. The structuring is in particular a corrugation configuration, a curvature configuration, a scalloping or a folding configuration of the sheet. It may also have microstructures as well as small incisions and openings. The catalytically active surface area can also be increased in that way. In regard to the structuring, nature and form of the layer, attention is directed in particular to EP 0 484 364, WO 93/20339, EP 0 152 560 and DE 29 611 143. Making up the catalytic converter from three sheets which are joined together, wherein the outermost one is structured, affords the possibility of the catalytic converter being held in a housing solely by virtue of a clamping force of that outer sheet. Such a holding action is facilitated if at least a part of a layer of the catalytic converter is flexible. That is in particular a part of the layer, which is supported against a reinforcement, in particular a wall of the housing or the small apparatus or implement or the internal combustion engine. In a further embodiment, to achieve a high level of stability for the catalytic converter, it has the configuration of a layer with a first metal sheet and a second metal sheet. In that arrangement the first sheet is preferably thicker than the second sheet by a factor of between 1.5 and 5. in particular between 2 and 4. When using metal foil of between 20 µm and 100 µm, this makes it possible to use the thinner foil which is particularly desirable in terms of a structuring, without having to abandon the idea of a self-stabilising catalytic converter. It is therefore preferable for the first sheet to be unstructured and for the second sheet to be structured. A further embodiment of the catalytic converter provides same with a flattened cross-section. If the directions in which the forces which are applied from 6 the outside will act on the catalytic converter are known, then with a flattened cross-section it is possible to provide a catalytic converter which enjoys particular stability in that direction. The catalytic converter can also be of such a design configuration that it has preferred directions in respect of the effect of external forces, in which directions the catalytic converter reacts elastically and possibly also necessarily plastically. Destruction of the catalytic converter can be prevented by virtue of established regions of the catalytic converter which, in the event of an excessively heavy loading, involve plastic deformation in order to receive and adsorb the forces acting. The catalytic converter can be arranged in an exhaust gas system which in internal combustion engines usually leads away there from. Equally however the catalytic converter can also be used in exhaust gas systems which are disposed in the casing of the internal combustion engine.. For both situations it is desirable for the housing of the catalytic converter to be part of the exhaust gas system. That can ensure dissipation of heat of the catalytic converter as it heats up by flow transfer to the exterior. The housing can be a bend tube or a component of a silencer or muffler of the exhaust gas system. That ensures compact installation of the catalytic converter without an additional space being required for same. In accordance with a further aspect of the invention, in order to make compact utilisation of the space involved, a silencer or muffler for an exhaust gas system of an internal combustion engine, in particular a small engine, is used by the silencer or muffler having means for receiving the above-described catalytic converter. That is for example a suitably designed and in particular adapted housing which facilitates disposing the catalytic converter therein and its fixing thereat. That can be achieved by means of a tubular casing as the housing as well as by virtue of a suitable spatial configuration in the casing of the internal combustion engine. Particularly in the case of small engines, the silencer/catalytic converter combination makes it possible to keep the exhaust gas systems thereof small. It is preferable for a part of the silencer or muffler to have means for fixing the catalytic converter. That can be teeth, notches, transverse web portions, channel means, grooves or similar structural means. If teeth or the like are used they co-operate with at least the oppositely disposed sheet. Teeth engage into same and thereby hold the entire catalytic converter. The service life of the catalytic converter also depends on the respective mode of operation of the internal combustion' engine and the area of use thereof. If the engine is only ever repeatedly operated for a short period of time, and if the engine is subjected to large forces acting thereon from the exterior, all that reduces the service life of the catalytic converter. 7 It is therefore desirable for the catalytic converter to be interchangeably fitted in position. In the case of the silencer or muffler the catalytic converter can for example be arranged in a top housing and a bottom housing. One of the two housing halves preferably has a reinforcement by which a force, in particular a clamping force, can be exerted on the catalytic converter. The reinforcement can be a transverse web or bar portion in the silencer or muffler, as well as one of the sound-damping structures of the silencer or muffler. A further possible way of holding the catalytic converter in the silencer or muffler involves so squeezing at least a part of the catalytic converter in the silencer or muffler that the catalytic converter is immovable. A further embodiment of a silencer or muffler which is particularly suitable for small engines has at least two parts, a top housing and a bottom housing. A partitioning wall divides the silencer or muffler into a first region and a second region. The partitioning wall and/or the silencer or muffler have means for holding a catalytic converter in each respective ones of the regions which are separated from each other. It is possible in that way for two catalytic converters to be disposed in one silencer or muffler. That is not necessarily the case. There may also be only a single one or also more than two catalytic converters. In accordance with a further concept of the invention there is also provided a process for the production of a catalytic converter carrier body which is arranged in an exhaust gas system of an internal combustion engine. in particular a silencer or muffler of a small engine, wherein - a structured sheet is wound on inclinedly around an at least partially curved elongate body. - subsequently at least a part of the elongate body with the sheet wound thereon is cut into a plurality of portions, and - a respective portion becomes a catalytic converter carrier body. That process is particularly suitable for a continuous production procedure, wherein the structured sheet can be unwound from an endless strip. The elongate body in turn can be a tube or also another suitably long available body. To provide for a particularly high degree of utilisation of space in order to afford a large catalytically active surface area the body has a hollow interior in which a further structured sheet is arranged. The catalytically active surface is then afforded by the sheet and/or the body being coated with a catalytically active layer prior to the winding-on operation or by the portion which has been cut off being coated with a catalytically active layer after the cutting operation. Depending on the respective way in which the sheets are fixed together, that can be effected by means of soldering, welding, adhesive or similar means but equally also by inherent stressing of one of the sheets, the moment when the catalytically 8 active layer is most appropriately to be applied is a matter of choice. To achieve a high degree of stability of the above-mentioned portion, it is provided that the body is a metal sheet which is thicker than the sheet which is to be wound on. Desirable values in respect of stability are achieved if the thicker sheet is about one to five times thicker than the sheet which is to be wound on. As described above a compact catalytic converter can be particularly inexpensively produced from the catalytic converter carrier body, in accordance with this method. Further advantages and features of the invention are illustrated in the following description of the drawing. Additional advantageous configurations can be achieved by combinations of the proviously disclosed features with those set out hereinafter. In the/accompanying drawing: Figure 1 shows a structured sheet in a housing. Figure 2 shows a further structured sheet in a housing. Figure 3 shows a catalytic converter with one and a half layers in a housing. Figure 4 shows 'a number of arrangements of catalytic converters in an internal combustion engine exhaust gas system. Figure 5 shows an arrangement of two catalysts in a silencer or muffler. Figure 6 shows a further catalytic converter having one and a half layers. Figure 7 shows a catalytic converter having one and a half layers, with forces acting thereon, Figure 8 shows a further arrangement of two catalytic converters in a housing of an exhaust gas system. Figure 9 shows a process for the production of a catalytic converter carrier body. Figure 10 shows a production process corresponding to that shown in Figure 9. Figure 11 shows a further production process. Figure 12 shows an arrangement for a production process corresponding to that shown in Figure 11. Figure 13 shows another production process. Figure 14 shows still another production process. Figure 15 shows a further housing for a catalytic converter. Figure 16 shows an embodiment of an outside surface of a catalytic converter. Figure 17 shows a possible arrangement of catalytic converters in another housing, and Figure 18 again shows a housing. Figure 1 shows a catalytic converter 1 which has a metal sheet 2. The sheet 2 is arranged in a housing 3 of an exhaust gas system and has a 9 catalytic coating 4. The sheet 2 is structured. The structure is a corrugation configuration. This makes it possible for the sheet 2 also to be arranged under.its inherent stress in the housing 3. That inherent stress is sufficient to fix the catalytic converter 1 in the housing 3. The structuring of the sheet 2 is so selected that passages 5 are formed by co-operation with the housing 3. The passages 5 embrace a part of the total cross-sectional area, to constitute a bordered-in cross-sectional area. The remaining area 6 in the housing 3. which is not enclosed by the passages, is less than SOX of the total housing cross-section illustrated, by virtue of the corrugation configuration. . That area 6 is emphasised by hatching to show it more clearly. Figure 2 again shows a structured sheet 2 forming a catalytic converter 1 in a housing 3. The sheet 2 has a corrugated structure which is so selected that a first corrugation crest 7 engages into an oppositely disposed first corrugation trough 8. That leads on the one hand to a further reduction in the area 6 and thus an increase in the bordered cross-sectional area. On the other hand the first corrugation crest 7 is intertwined or interlaced in non-contacting relationship with a second corrugation crest 9, Thus, in relation to forces acting thereon from the exterior, the catalytic converter 1 can react elastically by virtue of the fact that the spacing between the first corrugation crest 7 and the second corrugation crest 9 is available as a clearance. The elasticity characteristics of the catalytic converter 1 can be influenced by the nature of the connection of the sheet 2 to the housing 3. If only for example each second corrugation trough is connected to the housing 3, as is indicated by the connecting locations 10, the catalytic converter 1 admittedly remains fixed, but it is nonetheless movably held in the housing 3. In that respect the connecting location 10 may extend over the entire axial length of the catalytic converter 1. but equally it may be present only in a point-wise or portion-wise manner. That is indicated by the connecting locations 10.1 which occur as solder locations on both sides of a corrugation trough and which there extend in the axial direction of the catalytic converter. In contrast the connecting locations 10.2 are for example to be considered as spot or longitudinal welds. Figure 3 shows a preferred catalytic converter 1, involving one and a half layers, in a housing 3. One layer 11 is formed from a first sheet 12 and a second sheet 13. The first sheet 12 is unstructured. The second sheet 13 has a folded configuration as the structuring. The layer 11 is wound in such a way as to form a closed body 14. Arranged in that body 14 is a third sheet 15. which is supported at the first sheet 12 with its structuring. The area 6 which does not involve passages is once again considerably reduced by virtue of the third sheet 15. At the same time it additionally makes catalytically active surfaces available. To achieve a particular degree of elasticity but 10 also strength of the catalytic converter 1, the unstructured first sheet 12 is thicker than the second sheet 13 and the third sheet 15. The two structured sheets 13 and 15 therefore find with the first sheet 12 a static counterpart in relation to the housing 3. Figure 4 shows an internal combustion engine 16 to which an exhaust gas system 17 is connected. The exhaust gas system 17 has a bend region 18, a silencer or muffler 19 and connecting pipes 20. Arranged in the bend region 18 are a first catalytic converter 21. a second catalytic converter 22 and a third catalytic converter 23, each disposed in a respective pipe leading away from a cylinder. The first catalytic converter 21 is of a conical configuration, and the second catalytic converter 22 likewise. The third catalytic converter 23 in contrast has a bend, with its cross-section remaining substantially constant. A fourth catalytic converter 24 is arranged in a connecting pipe 20. It is of a regular cross-section which does not change over its :axial length. A fifth catalytic converter 25 is also disposed in the silencer\or muffler 19. The catalytic converter 25 is adapted to its housing 3 and v/ice versa. For that purpose the silencer or muffler 19 has holding means 26. such as for example an outwardly projecting portion or bulge portion 27. By Virtue of its size the catalytic converter 25 is a precise fit into the portion 27. By virtue of that arrangement it is possible for the fifth catalytic'converter 25 to be held in the silencer or muffler 19 solely by virtue of its inherent stress, in conjunction with the portion 27. Figure 5 shows another silencer or muffler 19. It is divided in its interior by a partitioning wall 28 into an upper region 29 and a lower region 30. A flow communication between the upper region 29 and the lower region 30. for the exhaust gas flow 31 passing through the silencer or muffler 19, is ensured by aperture means 32 in the partitioning wall 28. The silencer or muffler 19 has a top housing 33 and a bottom housing 34 which can be fixed together with ;the partitioning wall 28 by connecting means 35. The partitioning wall 28. the top housing 33 and the bottom housing 34 have holding means 26 for the upper catalytic converter 36 and the lower catalytic converter 37 disposed in the silencer or muffler 19. The holding means 26 are for example grooves 38, teeth 39 or also transverse web or bar portions 40. They come into contact at least with the respectively outwardly disposed sheet of the upper catalytic converter 36 and the lower catalytic converter 37. The one or more holding means 26 can also be arranged in such a way that at least a part of an end face 41 of the upper catalytic converter 36 and/or the lower catalytic converter 37 is used for fixing purposes. The illustrated silencer or muffler 19 is extremely compact and is preferably intended for use in particular in relation to small engines. The exhaust gas connections 42 provided for the exhaust gas flow 31 can be arranged in different ways 11 depending on the respective position of installation of the silencer or muffler 19. While the exhaust gas connections 42.1 are suitable for connection in an exhaust gas system extending in a straight line, the exhaust gas connections 42.2 are fitted to the silencer or muffler 19 in sideways relationship. That affords an advantage in terms of flow dynamics as the change in direction to the upper catalytic converter 36 or the change in direction from the lower catalytic converter 37 to the exhaust gas connection 42 no longer occurs. Figure 6 shows a circular catalytic converter 1. It is of such a construction as to involve one and a half layers. It has two thicker structured sheets, an inner sheet 43 and an outer sheet 44. An unstructured sheet 45 is arranged between the inner sheet 43 and the outer sheet 44. A corrugation configuration was adopted as the structuring of the inner sheet 43 and the outer sheet 44. If the corrugation troughs and the corrugation crests respectively of the two structured sheets 43 and 44 are arranged at approximately !the same spacing, the unstructured sheet 45 is capable of receiving forces acting on the arrangement and absorbing the energy by virtue of elastic defprmation. In addition the inner sheet 43 has additional half- structures 46. They subdivide the passages 5 which already exist or form passages in further cross-sectional regions of the otherwise free area 6. The half-structures 46 are formed for example by incisions in the inner sheet 43. in which case the material which has been cut into is displaced in an outward direction or an inward direction, in dependence on its position in the structure. Another possible way of providing holding structures 46 involves for example arranging additional sheet portions on the inner sheet 43. The use of half-structures or the like promotes passage formation over a large area in the catalytic converter 1. to achieve a small free area 6 and thus a large bordered cross-sectional area. Figure 7 also shows a catalytic converter 1 involving one and a half layers, on which external forces 47 are acting. The external forces 47 can be accommodated in operation of the catalytic converter 1 by deformation of the outer sheet 44. However they may also be applied for example deliberately in the production procedure in order to convert an otherwise round catalytic converter 1 into a catalytic converter 1 involving a flattened cross-sectional configuration.; The external forces 47 can also be utilised in order to fit the catalytic converter 1 into a housing. It is then held therein by its inherently produced stresses. Figure 8 shows an extremely compact arrangement of an upper catalytic converter 36 and a lower catalytic converter 37 in a housing 3. Both catalytic converters 36 and 37 are adapted to the shape of the housing 3 and permit an exhaust gas flow 31 to flow axially therethrough. The exhaust gas 12 flow can be guided in particular in such a way that it first flows through the upper catalytic converter 36 and then through the lower catalytic converter 37. The housing 3 with the two catalytic converters 36 and 37 is therefore to be disposed in a particularly space-saving arrangement for example in a silencer or muffler. In addition, like the catalytic converters 36 and 37. it can also be provided with a catalytically active coating. That applies not only specifically in regard to the illustrated housing but also in regard to other housings. There are also other uses for the unit 48 formed in that way. As it is easy to fit in position and remove by virtue of its structure, it is suitable for example as a replacement part in exhaust gas systems of internal combustion engines. The catalytically active surface area which is necessary when high exhaust gas flow rates are involved is then afforded by the exhaust gases flowing in succession through the upper catalytic converter 36 and the lower catalyticconverter 37. In that way it is also possible for a plurality of units 48 to be arranged one after the other to clean the exhaust gas flow 31. Figure 9 sh'ows a process for the production of a catalytic converter carrier body. A structured sheet 49 is inclinedly wound around an at least partially curved or cambered elongate body 50. The body 50 and the structured sheet 49 perform a relative movement for that purpose. That can be achieved for example by rotation of the body 50 and the advance movement thereof in such a way that the structured sheet 49 is drawn onto the body 50. That is indicated by the arrows on the sheet 49 and the body 50 respectively. In that operation the structured sheet 49 is connected to the body 50. Subsequently at least a part, of the elongate body 50 with the sheet 49 wound thereon is divided up into a plurality of portions 51. A laser is used here as a cutting unit 52. It is capable of cleanly cutting the portions 51 off the body 50. The cutting operation can in particular be implemented in such a way that there is no need for after-treatment of the portion 51. The portion 51. as the then finished catalytic converter body, can then be used as the catalytic converter 1. For that purpose the portion 51 is either subsequently provided with a catalytically active coating or the sheet 49 and the body 50 respectively already have that coating, in the winding-on operation. Figure 10 shows a further production process for a catalytic converter carrier body. A sheet 54 provided with a catalytically active coating is guided from an endless roll 53 to a direction-changing roller 55. From there the sheet 54 is (taken to a first profiling roller 56 which is in engagement with a second profiling roller 57. The flank geometry of the two profiling rollers 56. 57 defines the structuring of the sheet 54. It is then applied to a hollow body 58. The hollow body 58 has an internally disposed structured second sheet 59 which is also already provided with a catalytically active 13 coating. The hollow body 58 and the second sheet 59 can be produced for example prior to application of the sheet 54 from a formed layer which is then inclinedly wound in mutual relationship. That winding effect is indicated by the broken line 60. The hollow body 58 however may also be a tube into which the second sheet 59 has been inserted. In a somewhat different process the structured second sheet 59 is not inserted prior to division of the portions 51 but only after they have been cut off. Figure 11 shows a further production process for a catalytic converter carrier body. ; In this case also the sheet 54 which is provided with a catalytically active coating is applied to the hollow body 58 from an endless roll 53 (not shown). The hollow body 58 is produced from a layer which is inclinedly wound with itself. The winding effect can be seen at the butt join 60 between adjacent regions of the wound layer. The winding operation in particular can jbe implemented in such a way that passages 5, which are here indicated in broken line, are not interrupted in terms of continuity thereof by the winding; The same also applies in regard to the passages 5 of the sheet 54 which jis to be applied. The fact that the butt join 60 in the case of the sheet 54 to be applied is at an angle to that of the hollow body 58 means that a catalytic converter carrier body produced in that way can be of a particularly stable configuration. An advantage of the angular relationship of the butt joins relative to each other is that the later catalytic converter carrier body does not have any axially extending peripheral seam or join. On the contrary the loading at the seam is distributed over the entire periphery. The operation of applying the sheet 54 may also be effected in such a way that the layer of the hollow body 58 is virtually effectively clamped. The connection between the sheet 54 and the hollow body 58 can be produced by soldering directly after the operation of applying the sheet or also only in a subsequent working step. It 1s possible for example for the sheet 54 also to be first glued on and later soldered. The same also applies in regard to the connectionjof the layer of the hollow body 58. In a somewhat different production process the hollow body 58 is again produced from a layer as shown in Figure 11. This time however the layer is formed into the hollow body in such a way that there is an overlap region 61 as indicated in dash-dotted line. The overlap region 61 then stabilises the hollow body 58. At the same time it can also be used to produce a connection or join. For that purpose, in one configuration, the overlap region 61 has an adhesive or primer to which solder material is then applied. A corresponding procedure is also adopted with the sheet 54 to be applied. The elongate hollow body 58 which is produced in that way. with the applied sheet 54. is raised to suitable temperatures as a whole in a soldering oven so that the solder material produces a durable connection in the overlap region 61. In that case the 14 connection of the hollow body 58 to the applied sheet 54 is also produced by soldering. It is only thereafter that individual portions 51 are cut off. Figure 12 shows a process with which for example the catalytic converter carrier body described with reference to Figure 11 can be produced. From the endless roll 53 the sheet 54 which is still wide is passed to a first profiling roller 56 and a second profiling roller 57. After the profiling operation the sheet 54 is cut up into four individual sheets 54.1, 54.2. 54.3 and 54.4. That is effected by the cutting device 62 which has severing blades 63. From therd the severed sheets 54.1 to 54.4 pass to respective hollow bodies 58.1 to 58.4. They are each wound onto a respective one thereof. The forward feed direction of the hollow bodies 58.1 to 58.4 is indicated by the respective arrows. The production process illustrated is suitable for a continuous working procedure as the hollow bodies 58.1 to 58.4 can also be continuously produced in a similar manner in an upstream-disposed station. Figure 13 also shows a production process for a catalytic converter 1. A structured sheet 65 and an unstructured sheet 66 are introduced into a rotary body 64, as in the case of a sardine can opener, into a slot 67 in the rotary body 64. i When the rotary body 64 is rotated the two sheets 65, 66 are wound on in the form of a layer. The shape of the catalytic converter 1 produced in that way is dependent on the geometry of the rotary body 64. The cavity which is formed in the interior of the catalytic converter 1 produced in that way can be more likely large or also kept small, depending on the respective requirements involved. An additional, in particular structured sheet can also be introduced into that cavity. In such a development of the process for the production of the catalytic converter 1 the rotary body 64 can be left therein and then serves as stabilisation, by virtue of the thickness of its material. Figure 14 shows another production process for a catalytic converter 1. The catalytic converter 1 is produced by structured sheets 65 and unstructured sheets 66, being stacked one upon the other. In that way the catalytic converter 1 has at most two layers 11 with an area 6 which is not bordered-in in its interior; and which is defined by surrounding passages, in a closed configuration. The ends 68 of the structured and unstructured sheets 65. 66, said ends projecting beyond the actual subsequent catalytic converter 1. are bent over in the direction indicated by the arrows so as to form a casing around the catalytic converter 1. For-that purpose the operation of bending the ends 68 is advantageously effected not only for a single sheet but for all sheets jointly in one working step. This is irrespective of whether the sheets involved are structured sheets 65 or unstructured sheets 66. An advantageous process for that purpose is firstly stacking the structured sheets 65 and the unstructured sheets 66 without folding over the ends 68. 15 It is only then that the ends 68 are folded over. This can be in one direction, but it can also be in mutually opposite directions. For that purpose the entire stack can be turned round or shaping devices engage the ends 68 at the outside and bend them over. Figure 15 shows a further housing 3 for a catalytic converter 1. The housing 3 can be used as a silencer or muffler housing. It has a base body 69 and it has inwardly extending corrugation portions 70 which are of such a configuration that they engage into corresponding recesses 71 in the catalytic converter 1 which is disposed in the interior of the housing 3, and thus fix it in position. The base body 69 comprises a first part 69.1 and a second part 69.2 which each have a bent-over end 72. The ends 72 can be joined together, for example by a welded seam or by soldering. That then provides a one-piece base body 69. Otherwise it is in two pieces, in which case it is then held together in co-operative relationship by engagement of the ends 68 into the catalyst 1. A first cover 74 and a second cover 75 are disposed on the base body 69 for laterally covering over the assembly and preventing a discharge flow of the gas flow 73 which is passing through the catalytic converter 1. Disposed in the first cover 74 are inward curvature portions 76 which engage into corresponding recesses 71 in the catalytic converter 1. The catalytic converter 1 is laterally fixed in that way. That method of closing the housing 3 by means of covers which are to be mounted at the sides permits the catalytic converter 1 to be replaceable by inserting into and removing it from the base housing 69. Figure 16 shows an embodiment of an outside surface 77 of a catalytic converter 1. The outside surface 77 is profiled and thereby prevents undesired displacement of the catalytic converter 1 in a housing which is not shown here. The profiling 78 can be non-directional or random, or oriented. At any event the profiling 78 provides that the catalytic converter 1 is prevented from being slowly pushed out of the housing, for example by virtue of vibration. An inclined tooth-like profiling has proven to be advantageous. On the one hand this configuration can be so oriented that there is a preferential direction in terms of preventing displacement of the catalytic converter in the housing. For example attaching a mechanical stop arrangement to the housing: in relation to the direction which is opposite to that preferential direction ensures that removal of the catalytic converter 1 from the housing is possible only after the way has been cleared by the mechanical stop arrangement. Not only the catalytic converter 1 but also the housing 3 or a silencer or muffler 19 itself may have a profiling configuration as just described above. Figure 17 shows a possible arrangement of a first catalytic converter 21. a second catalytic converter 22 and a third catalytic converter 23 in another 16 housing 3. The! housing 3, for example a silencer or muffler 19. has a top housing 33 and a bottom housing 34. The top housing 33 is closed and held to the bottom housing 34 by way of a mutually engaging closure mechanism 79. End regions 80 of the walls of the top housing 33 and the bottom housing 34 respectively also form a kind of hook. The hooks 81 are of such a configuration that, when the top housing 33 is pressed onto the bottom housing 34, the end regions 80 of the top housing 33 are urged inwardly and the end regions 80 of the bottom housing 34 are urged outwardly. In that way then the hooks 81 which are disposed in mutually opposite relationship can engage one into the other. The internal configuration of the housing 3 can be used in different ways for the catalytic converter or converters 21. 22 and 23 which are to be arranged therein. While the first catalytic converter 21 which is shown in section is disposed alone in the housing 3, the arrangement of the second catalytic converter 22 and the third catalytic converter shows how the three-dimensional geometry of the top housing 33 and the bottom housing 34 with the hook configurations thereof is utilised for holding a respective one of the two catalytic converters in the upper region 29 and the lower region 30 respectively. In the case of the first catalytic converter 21 in contrast a part of the closure mechanism 79 engages into the catalytic converter 21 itself and thus, fixes it in the housing 3. Figure 18 a^ain shows a housing 3. The housing 3 again has a top housing 33 and a bottom housing 34, wherein they of such a configuration that they fix the catalytic converter or converters to be arranged in the interior thereof, by virtue of the shape thereof. The catalytic converter itself can therefore be not only of a more or less quadrangular configuration but equally can also be concave or convex. Further shapes are also possible, whether hexagonal or other polygonal configurations as well as curved or other complicated geometries. The present! invention provides in particular a cata1ytic converter and a process for the production of a cata1ytic converter carrier body from which that catalytic! converter can be produced, which is of a simple compact structure while nonetheless being effectively useful in respect of its exhaust gas cleaning characteristics. A preferred area of use of a catalytic converter of this kind is in connection with small engines. 17 List of references 1 catalytic converter 2 sheet 3 housing 4 catalytically active coating 5 passage 6 area which is not completely passaged and bordered-in 7 first corrugation crest 8 first corrugation trough 9 second corrugation crest 10 connecting location 10.1 solder location 10.2 spot or longitudinal weld 11 layer 12 first sheet 13 second sheet 14 body 15 third sheet 16 internal combustion engine 17 exhaust gas system 18 bend region 19 silencer or muffler 20 connecting pipe 21 first catalytic converter 22 second catalytic converter 23 third catalytic converter 24 fourth catalytic converter 25 fifth catalytic converter 26 holding means 27 bulge portion 28 partitioning wall 29 upper region 30 lower region 31 exhaust gas flow 32 aperture means 33 top housing 34 bottom housing 35 connecting means 36 upper catalytic converter 37 lower catalytic converter 11 18 38 groove 39 tooth 40 transverse bar portion 41 end face 42. 42.1. 42.2 exhaust gas connection 43 inner thicker sheet 44 outer thicker sheet 45 unstructured sheet 46 half-structure 47 external force 48 unit 49 structured sheet 50 elongate curved body 51 cut-off portion 52 severing unit 53 endless roll 54 sheet with catalytically active coating 55 direction-changing roller 56 first profiling roller 57 second profiling roller 58 hollow body 59 structured second sheet 60 butt join 61 overlap region 62 cutting device 63 severing blade 64 rotary body 65 structured sheet 66 unstructured sheet 67 slot 68 ends 69 base housing 69.1 first part of the base housing 69.2 second part of the base housing 70 inwardly extending corrugation portion 71 recess 72 bent-over end 73 gas flow 74 first cover 75 second cover 76 inwardly extending curvature portion 19 77 external surface 78 profiling 79 closure mechanism 80 - end region of the wall 81 hook 20. WE CLAIM: 1. Catalytic converter (1:21,22,23,24,25:36:37) with a housing (3) for an exhaust gas system (17) of an internal combustion engine (16), in particular a small engine, wherein the catalytic converter (1;21,22,23,24,25;36,37) has at least one structured sheet (2?13) which is provided with a catalytically active material and which is wound and which forms passages (5) through which exhaust gas can flaw and which at least partially bears against the housing (3), wherein closed passages (5) are formed by the structuring of the sheet (2,13) and the housing (3) or a sheet of a layer having a smooth and structured sheet, so that, as considered over a cross-section of the housing (3) a cross-sectional area which is bordered in by said closed passages (9) constitutes at least half of the total cross-sectional area of the housing (3) and wherein the catalytic eonv»rt«r (1| 21,22,23,24,23$36,37) has at most two layers (11), characterized in that the structured sheet (49) is wound inclinaly around an at least partially curved elongate body (50). 2. Catalytic converter (1;21,22,23,24,25;36,37) as claimed in claim 1, wherein the bordered cross-sectional area constitutes at least two-thirds of the total cross-section of the housing (3). 3- Catalytic converter (1;21,22,23,24,25:36,37) as claimed in claim 1 wherein the sheet (2;13) is wound in a manner so that the structuring comes to lie in mutually opposite relationship 21. 4. Catalytic converter (1;21,22,23,24,25;36,37) as claimed in claim 3, wharein the oppositely disposed structurings are interlaced with each other without touching each other- 5. Catalytic converter (1;21,22,23,24,25;36,37) as claimed in claim 3 or 4, wherein the bordered cross-sectional area constitutes at least three quarters of the total cross-sectional area of the housing (3). 6. Catalytic converter (1;21,22,23,24,25;36,37) as claimed in claims 1,2 or 3, wherein the catalytic converter (1;21,22,23,24,25? 36,37) has a stabilizing reinforcement. 7. Catalytic converter (1;21,22,23.24.25;36,37) as claimed in claim 1,2 or 3,wherein each passage-forming sheet of the catalytic converter Cl;21,22,23,24,25;36,37) bears against a reinforcement. 8. Catalytic converter (1;21,22,23,24,25;36,37) as claimed inclaims 1,2 or 3?wherein the passage-forming sheet side and an underside and wherein the top-side and underside of the sheet each bear against a respective reinforcement. 9. Catalytic converter (1;21,22,23,24,25;36,37) as claimed in claim 1,2 or 3 wherein it comprises a layer (11) with an un-saturated sheet (12) and a structured sheet (13)- 22. 10. Catalytic converter (1,21,22,23,24,25;36,37) as claimed in claim 1,2 or 3 comprising an unstructured sheet (13) with a top- with a side and an underside, a respective structured sheet (12,14) being arranged at each of the topside and underside- 11. Catalytic converter (1;21,22,23.24.25'36,37) as claimed in claim 1, 2 or 3 } wherein the structuring is a corrugation configuration, a bend configuration or a scallop configuration. 12. Catalytic converter (1;21,22,23,24,25;36,37) as claimed in claim 1,2 or 3, wherein at least a part of the layer (11) of the catalytic converter (1;21,22,23,24,25;36,37) is flexible, in particular a part of a layer which bears against a reinforcement, in particular a wall. 13. Catalytic converter (1;21,22,23,24,25;36,37) as claimed in claim l,2,or 3, wherein a first sheet (12) with a second sheet (13) forms a layer (11) and wherein the first sheet (12) is thicker than the second sheet (13), preferably by a factor of between 1.3 and 3, in particular between 2 and 4. 14. Catalytic converter (1;21,22,23,24,25(36,37) as claimed in claim 13, wherein in the first sheet (12) is unstructured and the second sheet (13) is structured. 14. 23. 15. Catalytic converter (1;21,22,23,24,25;36,37) as claimed in . claim 1,2 or 3] wherein it is of a flattened cross-section. 16. Catalytic converter (1;21,22,23,24,25;36,37) as claimed in Claim 1,2 or 3? wherein a surface (71) of the catalytic converter (1) which is disposed in opposite relationship to a surface (7Ø,76) of the housing (3), is adapted to the surface (70,76) of the housing (3). 17. Catalytic converter (1;21,22,23,24,25;36,37) as claimed in claim 1 2 or 3 comprising a profiled external surface (77) to prevent unintended displacement of the catalytic converter (1) in the housing (3). 18. Catalytic converter (1;21,22,23,24,25;36,37) as claimed in claim 17, wherein the profiling (78) is directed, that it is in particular an inclined tooth profiling. 19- Catalytic converter (1;21,22,23,34,25;36,37) as claimed in claim 1,2 or 3;wherein it is so configured that the housing (3) is part of the exhaust gas system (17). 20, Catalytic converter (1;21,22,23,24,25;36,37) as claimed in claim 19, wherein the housing (3) is a manifold pipe or a component of a silencer (19) of the exhaust gas system (17). 24. 21. Catalytic converter (1,21,22,23,24-25;36,37) as claimed in claim 1,2 or 3 comprising a silencer (19) for an exhaust gas sytem of an internal combustion engine (16), in particular a small engine, wherein the silencer (19) has means (26) for receiving a catalytic converter (1;2i,22,23,24,25;36,37)- 22. Catalytic converter (1;21,22,23,24,25;36,27) as claimed in claim 21, wherein part of the silencer (19) has means (26,27;38,39,40) for fixing the catalytic converter (1;21,22,23,24.25 5 36,37 >. 23. Catalytic converter (1;21,22,23,24,25;36,37) as claimed in in claim 21 or 22, wherein the catalytic converter (1;21,22,23,24,25;36,27> is interchangeably insertable. 24. Catalytic converter (1;21,22,23,24,25:36,37) as claimed in claim 21, wherein the silencer (19) has a reinforcement through which a force, in particular a clamping force is exertable on the catalytic converter (1;21,22,23,24,25;36,37, (1;21,22,23,24,25;36,37). 25. Catalytic converter (1;21,22,23,24,25536,37) as claimed in claim 21, wherein a part the catalytic converter (1521,22,23,24,23536,37) is squeezed by the silencer (19>- 25. 26. Catalytic converter (1521,22,23,24,25536,37,) as claimed in claim 1 comprising a silencer (19) having at least two parts (33,34) wherein a partioning wall (28) divides the silencer (19) into a first region (29) and a second region (30) and wherein the partitioning wall (28) and/or the silencer (19) has means (26,27538,39,40) for holding a catalytic converter (1521,22,23,24.23536,37) in each respective region (29,30) and the partitioning wall is arranged substantially parallel to a through-flow direction through the silencer (19). 27. Catalytic converter as claimed in claim 26 wherein said two parts (33),34) comprise an intermeshing locking mechanism (79) which is used for holding the catalytic converter (21,22,23), 28. A process for the production of a catalytic converter carrier body as claimed in any of claims 1 to 27, the catalytic converter carrier body capable of being disposed in an exhaust gas system (17) of an internal combustion engine (16), in particular in a silencer (19) of small engine, wherein — a structured sheet (49) is wound inclinedly around an at least partially curved elongate body (50), — subsequently at least a part of the elongate body (50) with the wound sheet (49) is divided up into a plurality of portions (51), and — a respective portion (51) becomes a catalytic converter carrier body- — 26. 29- A process as claimed in claim 28, wherein the body (50,58) has a hollow cavity therein in which an additional structured sheet (59) is arranged. 30. A process as claimed in claim 23 or 29, wherein the sheet (49:54$59) and/or the body (50;58) are coated with a catalytically active layer (4) prior to the winding-on ope nation. 31 - A process as claimed in claim 28 or 29, wherein the portion (51) is coated with a catalytically active layer (4). 32. A process as claimed in claim 28 or 29 wherein the body (50958) is a sheet which is thicker than the sheet (49;54s59) which is to be wound on, and in particular is about 1 to 5 times thicker. 33- A process as claimed in claim 28 or 29, wherein the sheet (49;54;59) which is to be wound on is unwound from an endless sheet strip (53) - 34, A process as claimed in claim 28 or 29, wherein a catalytic converter (1$21,22,23,24,25;37,38) as claimed in claim 1 to 27 is made from the catalytic converter carrier body and wherein due to the structuring of the sheet (2;13) in addition with the housing 27. (3) or a sheet of a layer closed passages (5) are formed such that, conoidered over a cross- section of the housing (3)a cross-, sectional area which is bordered by the closed passages (5) conotitutaffl at least half of the total cross-sectional area of the housing (3). Dated this 28th day of January 1998 This invention relates to a catalytic converter [1;21,22,23,24.2S;3A,37, ) with a housing (3) for an exahust gas system (17) of an internal combustion engine (16), in particular a Small engine, wherein the catalytic converter .(1;21,22,23,24,25;36,37) has at least one structured sheet (2;13) which is provided with a catalytically active material and which is wound and which forms passages (5) through which exhaust gas cart flow and which at least partially bears against the housing (3), wherein closed passages (5) are formed by the structuring of th« sheet (2,13) and the housing (3) or a sheet of a layer having a smooth and a structured sheet, sa that, as considered over a cross-section of the housing (3) a cross-sectional area which is bordered in by said closed passages (5) constitutes at least half of the total cross-sectional area of the housing (3), wherein the catalytic converter (1;21,22,23,24,25;36,37) has atmost two layers (11) . The structured sheet (49) is wound on incl ined around an at least partially curved elongate body (50),

Documents:

00146-cal-1998 abstract.pdf

00146-cal-1998 claims.pdf

00146-cal-1998 correspondence-1.1.pdf

00146-cal-1998 correspondence.pdf

00146-cal-1998 description(complete).pdf

00146-cal-1998 drawings.pdf

00146-cal-1998 form-1.pdf

00146-cal-1998 form-2.pdf

00146-cal-1998 form-3.pdf

00146-cal-1998 form-5.pdf

00146-cal-1998 pa.pdf

00146-cal-1998 priority document.pdf

146-cal-1998-granted-abstract.pdf

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

146-cal-1998-granted-claims.pdf

146-cal-1998-granted-correspondence.pdf

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

146-cal-1998-granted-drawings.pdf

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

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

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

146-cal-1998-granted-form 3.pdf

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

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

146-cal-1998-granted-pa.pdf

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

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

146-cal-1998-granted-specification.pdf

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