Patent Publication Number: US-6660235-B1

Title: Catalyst carrier configuration for installation close to an engine

Description:
CROSS-REFERENCE TO RELATED APPLICATION: 
     This application is a continuation of copending International Application No. PCT/EP98/05364, filed Aug. 24, 1998, which designated the United States. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to a catalyst carrier configuration, a structural unit having catalyst carrier configurations and further relates to an exhaust system of an internal combustion engine. 
     For catalytically converting components of an exhaust gas from an internal combustion engine, it is known to apply at least one catalytically active substance to a catalyst carrier. The catalyst carrier has gas passages through which an exhaust gas can flow. The gas passages extend in the longitudinal direction of the catalyst carrier. It is known to provide a catalyst carrier in the form of a honeycomb. The catalyst carrier may be formed from layers of sheet metal which are at least partially structured. Furthermore, catalyst carriers which are formed of a ceramic material are known. Such catalyst carriers are extruded. 
     The catalyst carrier is disposed in a housing which is part of an exhaust system. Various configurations of the housing are known depending on the material of the catalyst carrier. 
     International Patent Publication WO 90/02251 describes a housing with a catalyst carrier which is suitable in particular for installation close to the engine and within the exhaust system. The housing has a larger cross section than the catalyst carrier. The housing has an approximately rectangular opening, the length of which is greater than the maximum length of the catalyst carrier and the width of which is greater than the maximum width of the catalyst carrier. The catalyst carrier is attached to a flat or curved retention plate which has a greater length and width than the opening in the housing. The retention plate serves as a closure cover for the housing, the catalyst carrier projecting into an inner chamber in the housing. This simplifies installation of the catalyst carrier in the housing and removal of the catalyst carrier from the housing. 
     Further configurations of catalyst carrier configurations are known, for example, from International Patent Publications WO 96/27735, WO 96/01698 and WO 96/19647. 
     Particularly in the case of internal combustion engines which are installed in passenger vehicles, installing a catalyst carrier close to the engine is not without problems, since the spatial conditions inside an engine chamber of the vehicle are relatively constricted. 
     Published German Patent Application DE 26 35 725 A1 discloses a catalyst carrier configuration having a housing in which at least one catalyst carrier is disposed. The catalyst carrier has a plurality of passages which are separated from one another by partitions and extend in an axial direction of the catalyst carrier. The housing has a flange which is directed essentially radially outwards. The flange can be provided between a cylinder head and a manifold of an internal combustion engine. The housing is formed integrally with the flange. 
     Published German Patent Application DE 43 17 092 A1 discloses a catalyst carrier configuration which is disposed in the exhaust manifold of an internal combustion engine. The catalyst carrier configuration has a housing which is configured in the form of a frame. The framelike housing has collar-like beads, in order to ensure that a catalyst carrier is fixed both radially and axially in the housing. The housing is connected to a flange. The flange is welded to one of the collar-like beads. It is also known from Published German Patent Application DE 43 17 092 A1 that it is possible to connect the flange to a plurality of housings. 
     Published German Patent Application DE 43 22 526 A1 discloses a further configuration of a catalyst carrier configuration for an internal combustion engine. The catalyst carrier configuration has a housing in which a catalyst carrier is provided. A flange which has a collar which is fixed to the housing is connected to the housing. The flange is fixed, together with an exhaust pipe, to the cylinder head of an internal combustion engine. 
     SUMMARY OF THE INVENTION 
     It is accordingly an object of the invention to provide a catalyst carrier configuration which overcomes the abovementioned disadvantages of the heretofore-known configurations of this general type and which is of simple construction and allows installation close to an engine. 
     A further object of the invention is to provide a structural unit which simplifies the assembly of at least two catalyst carrier bodies in the vicinity of the internal combustion engine. 
     A still further object of the invention is to provide an exhaust system of an internal combustion engine which can be produced with little outlay. 
     With the foregoing and other objects in view there is provided, in accordance with the invention, a catalyst carrier configuration, including: 
     a housing having an outer wall; 
     at least one catalyst carrier body disposed in the housing, the at least one catalyst carrier body defining an axial direction and having partition walls defining a plurality of passages separated from one another by the partition walls and extending essentially in the axial direction; and 
     at least one flange surrounding at least the at least one catalyst carrier body and extending essentially radially outwards from the at least one catalyst carrier body, the at least one flange having at least one section extending at least partially into the outer wall and being configured to be disposed between a cylinder head and a manifold of an internal combustion engine. 
     In other words, the construction of the catalyst configuration according to the invention has a housing in which a catalyst carrier body is disposed which has a plurality of passages which are separated from one another by partition walls and extend in an axial direction of the catalyst carrier body. The housing extends at least partially in an axial direction of the catalyst carrier body. The configuration according to the invention has a housing which has at least one flange which is directed essentially radially outwards, at least partially surrounds the catalyst carrier body and can be disposed between a cylinder head and a manifold of an internal combustion engine. The flange has at least a section which projects at least partially into the housing. This construction of the catalyst configuration according to the invention forms a sharp transition between the housing and the flange, so that the catalyst carrier configuration according to the invention requires relatively little installation space. Particularly in the case of existing internal combustion engines, the problem exists that they cannot be retrofitted with catalyst carrier configurations of this type since a catalyst carrier configuration as is known, for example, from Published German Patent Application DE 43 22 526 A1 has a radius of curvature in the transition region between the exhaust manifold or the cylinder head and the housing. Such a catalyst carrier configuration can only be fitted by adapting the further components. With the catalyst carrier configuration according to the invention it is not absolutely necessary to adapt the exhaust manifold or the cylinder head in this way. 
     Due to the fact that the flange extends at least partially into the housing, the load on a joint between flange and housing is also relieved, since some of the forces acting on the catalyst carrier body and the housing are introduced directly into the flange via the housing. Relieving the load on the joint between the housing and the flange also has a beneficial effect on the service life and durability of the catalyst carrier configuration. 
     The construction of the catalyst carrier configuration according to the invention also allows retrofitting on existing internal combustion engines, with the result that emissions of certain harmful components of the exhaust gas can be reduced. 
     The catalyst carrier configuration preferably has dimensions which are such that the catalyst carrier body can be introduced at least partially into an outlet passage from an internal combustion engine. This configuration means that the catalyst carrier body, which is provided with a catalyst, can quickly be brought to its operating temperature, so that the emission of harmful components is reduced during a cold-start phase of an internal combustion engine, in particular a vehicle engine. 
     In accordance with an advantageous feature of the invention, the housing has on or in its outer wall a recess into which at least one section of the flange projects. The recess is preferably formed by a groove, in particular a continuous, encircling groove. The flange has a passage opening which preferably has an internal diameter which is greater than the external diameter of the housing. The flange is positioned in the region of the groove. Due to a radially outwardly directed deformation of the housing, at least in the region of the groove, the section of the flange passes into the recess. The plastic deformation of the housing can be achieved by placing the housing under a sufficiently high internal pressure. If appropriate, the deformation of the housing may take place at an elevated temperature. 
     In accordance with another feature of the invention, the recess is formed by at least one radially outwardly directed stamped or swaged section in the outer wall. The swaged or stamped section is preferably structured in the form of a bead. 
     In accordance with another feature of the invention, a section of the flange extends as far as the catalyst carrier body. If the catalyst carrier configuration is configured in this way, the housing is preferably of two-part construction. 
     In accordance with yet another feature of the invention, the housing has an extent in the axial direction of the catalyst carrier body which is smaller, preferably significantly smaller, than a length of the catalyst carrier body. As a result, the catalyst carrier configuration has a relatively low heat-storage mass, so that an operating temperature of the catalyst carrier configuration can be reached more quickly. A further advantage of this configuration is that the external dimensions of the catalyst carrier configuration can be reduced to a required level so that when the catalyst carrier configuration is disposed in an outlet from an internal combustion engine there is no need to enlarge an outlet passage. It is also achieved that the free flow cross section in the outlet passage is reduced by the catalyst carrier configuration only by an insignificant amount. Furthermore, the flow behavior of the exhaust gas is affected only insignificantly. 
     A housing whose extent in the axial direction of the catalyst carrier body is smaller, preferably significantly smaller, than a length of the catalyst carrier body is suitable in particular for accommodating metallic catalyst carrier bodies which are wound helically or spirally. 
     If it is intended, instead of a helically or spirally wound catalyst carrier body, to provide, for example, a catalyst carrier body which is wound in the form of an S in the housing, it is advantageous for the housing to be formed by at least two housing parts, each housing part extending over part of the longitudinal extent of the catalyst carrier body. This configuration of the housing has the advantage that it prevents the catalyst carrier body being spread open by the housing parts. It is not necessary for the overall length of the individual housing parts to correspond to the overall length of the catalyst carrier body. There may be free sections between individual housing parts. Given a sufficiently long housing, it is also possible for a catalyst carrier body which is wound in the form of an S to be disposed in a single-piece housing. 
     In accordance with yet another feature of the invention, the housing or the housing parts are provided in the form of a ring or sleeve. This configuration has the advantage that the housing or the housing parts are relatively simple to produce. The external contour of the housing or the housing parts preferably corresponds to the cross section of the outlet passage or of the exhaust-gas flow path adjoining the outlet passage. 
     According to a further advantageous embodiment of the invention, the flange forms a single carrying unit together with a housing or with a housing part. This has the advantage that there is no need to handle a plurality of parts. 
     According to a further advantageous embodiment of the carrying unit, the housing or a housing part have at least one stop which can be brought to bear against a catalyst carrier body. This allows a defined installation position of a catalyst carrier body inside the housing or the housing part. 
     Preferably, the catalyst carrier configuration is configured in such a way that the flange has at least one sealing surface for gastight connection to a manifold and a cylinder head. The sealing surface is preferably of annular construction, so that it surrounds the catalyst carrier body. In this case, a preferred embodiment of the catalyst configuration is one in which the flange itself forms a seal. Such a catalyst carrier configuration is suitable particularly when the catalyst carrier configuration is disposed directly on the internal combustion engine, since it is possible to dispense with additional sealing devices. Thus the flange forms a seal between an engine block and a manifold of the internal combustion engine. The proximity of the catalyst carrier configuration to the combustion chamber of an internal combustion engine ensures that the catalyst carrier body heats up relatively quickly, with the result that the catalyst carrier configuration can be fully effective within a short time. The flange preferably forms a metallic seal. 
     Depending on the geometry of the seal, it may, under certain circumstances, be expedient to provide the flange with at least one sealing element, with the result that the costs of producing the flange can be reduced, since there is no need to accurately form sealing surfaces on the flange. 
     According to a further advantageous embodiment of the catalyst carrier configuration, the catalyst carrier body is a metallic catalyst carrier body, preferably a monolithic honeycomb body. Using a metallic catalyst carrier body has the advantage that the catalyst carrier body can be soldered at least to the housing and/or the flange, so that an increased stability of the catalyst carrier configuration is achieved. 
     The metallic catalyst carrier body may include layers of metal sheet which are at least partially structured. As an alternative, the catalyst carrier body may be produced from a sintered metal. 
     As an alternative to a metallic catalyst carrier body, it is also possible to use a ceramic catalyst carrier body. In this case, however, it should be ensured that the different thermal expansions caused by different coefficients of expansions of the materials of the catalyst carrier body and of the housing, which is metallic, are compensated for by suitable measures. 
     According to a further advantageous embodiment of the catalyst carrier configuration, the catalyst carrier body has at least one region which has at least one passage which has a larger cross section than the further passages. This measure ensures that the flow behavior of the exhaust-gas stream is not affected, or is affected only to a very slight extent, by the catalyst carrier body. Such an effect is important in particular if it has a feedback effect on the mixture formation within a combustion chamber of an internal combustion engine. 
     With the objects of the invention in view there is also provided, a structural unit, including: 
     at least two catalyst carrier configurations, each including a housing having an outer wall and a catalyst carrier body disposed in the housing, the catalyst carrier body defining an axial direction and having partition walls defining a plurality of passages separated from one another by the partition walls and extending essentially in the axial direction; and 
     a common flange surrounding the catalyst carrier body of each of the at least two catalyst carrier configurations and extending essentially radially outwards, the common flange having at least one section extending at least partially into the outer wall of each of the at least two catalyst carrier configurations and being configured to be disposed between a cylinder head and a manifold of an internal combustion engine. 
     The number of catalyst carrier configurations preferably corresponds to the number of outlet passages from an internal combustion engine. As a result, it is possible to reduce the assembly outlay on the catalyst carrier configurations. In particular in the case of a structural unit in which the number of catalyst carrier configurations corresponds to the number of outlet passages of an internal combustion engine, it is possible, given a suitable configuration of the internal combustion engine and an appropriately configured structural unit, to connect this structural unit directly to the internal combustion engine, so that part of each catalyst carrier body projects into an outlet passage of the internal combustion engine. 
     Preferably, such a structural unit is configured in such a way that each catalyst support is disposed inside a sealing surface. As an alternative, appropriate seals may be formed on the joint or common collar for each catalyst support. 
     With the objects of the invention in view there is also provided, an exhaust system for an internal combustion engine, including: 
     an exhaust system component defining at least one exhaust flow path; and 
     a catalyst carrier configuration including a housing having an outer wall, at least one catalyst carrier body disposed in the housing and provided at least partly in the at least one exhaust flow path, the at least one catalyst carrier body defining an axial direction and having partition walls defining a plurality of passages separated from one another by the partition walls and extending essentially in the axial direction, and a at least one flange surrounding at least the at least one catalyst carrier body and extending essentially radially outwards from the at least one catalyst carrier body, the at least one flange having at least one section extending at least partially into the outer wall and being configured to be disposed between a cylinder head and a manifold of an internal combustion engine. 
     With the objects of the invention in view there is further provided, an exhaust system for an internal combustion engine, including: 
     an exhaust system component defining exhaust flow paths; and 
     a structural unit including at least two catalyst carrier configurations, each including a housing having an outer wall and a catalyst carrier body disposed in the housing and provided at least partly in a respective one of the exhaust flow paths, the catalyst carrier body defining an axial direction and having partition walls defining a plurality of passages separated from one another by the partition walls and extending essentially in the axial direction, and a common flange surrounding the catalyst carrier body of each of the at least two catalyst carrier configurations and extending essentially radially outwards, the common flange having at least one section extending at least partially into the outer wall of each of the at least two catalyst carrier configurations and being configured to be disposed between a cylinder head and a manifold of an internal combustion engine. 
     The exhaust systems according to the invention make it possible to install catalyst carrier bodies in the immediate vicinity of an internal combustion engine. 
     Preferably, one catalyst carrier body is in each case disposed in each flow path, making it possible to reduce the emission of harmful components in the exhaust gas. In order to make the exhaust system as effective as possible and to avoid bypass flows of an exhaust gas, each catalyst carrier body with a housing has a cross section which essentially corresponds to a cross section of an exhaust-gas flow path. 
     According to a further advantageous embodiment of the exhaust system having at least one manifold which has at least one flange for connection to an internal combustion engine, the collar bears at least partially against the flange. In particular, the collar is configured in such a way that it can be connected to the flange in a gastight manner. Other features which are considered as characteristic for the invention are set forth in the appended claims. 
     Although the invention is illustrated and described herein as embodied in a catalyst carrier configuration for installation close to the engine, a structural unit having catalyst carrier configurations and an exhaust system, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
    
    
     The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front view of a first exemplary embodiment of a catalyst carrier configuration according to the invention; 
     FIG. 2 is a sectional side view of the catalyst carrier configuration according to FIG. 1; 
     FIG. 3 is an enlarged sectional view of a detail X according to FIG. 2; 
     FIG. 4 is a front view of a second exemplary embodiment of a catalyst carrier configuration according to the invention; 
     FIG. 5 is a sectional view of the catalyst carrier configuration according to FIG. 4; 
     FIG. 6 is an enlarged sectional view of a detail X according to FIG. 5; 
     FIG. 7 is a front view of a third exemplary embodiment of a catalyst carrier configuration according to the invention; 
     FIG. 8 is a sectional side view of the catalyst carrier configuration according to FIG. 7; 
     FIG. 9 is an enlarged sectional view of a detail X according to FIG. 8; 
     FIG. 10 is a full sectional view of a further exemplary embodiment of a catalyst carrier configuration according to the invention; 
     FIG. 11 is an enlarged sectional view of a detail X according to FIG. 10; 
     FIG. 12 is a front view of a further exemplary embodiment of a catalyst carrier configuration according to the invention; 
     FIG. 13 is a sectional side view of the catalyst carrier configuration according to FIG. 12; 
     FIG. 14 is an enlarged sectional view of a detail X according to FIG. 13; 
     FIG. 15 is a front view of a further exemplary embodiment of a catalyst carrier configuration according to the invention; 
     FIG. 16 is a sectional side view of the catalyst carrier configuration according to FIG. 15; 
     FIG. 17 is an enlarged sectional view of a detail X according to FIG. 16; 
     FIG. 18 is a plan front view of a first exemplary embodiment of a carrying unit with a catalyst carrier body according to the invention; and 
     FIG. 19 is a partial sectional view an exhaust system according to the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the figures of the drawings in detail and first, particularly, to FIGS. 1 and 2 thereof, there is shown a first exemplary embodiment of a catalyst carrier configuration. The catalyst carrier configuration has a housing  1  which is of two-part construction. The housing  1  has a first housing part  2  and a second housing part  3 . The first housing part  2  and the second housing part  3  are of essentially tubular construction. A catalyst carrier or more specifically a catalyst carrier body  4  is provided inside the housing  1 . The catalyst carrier  4  has a plurality of passages  8  which are separated from one another by partitions or partition walls  7  and extend in the longitudinal direction of the longitudinal axis  12  of the catalyst carrier  4 . In the exemplary embodiment illustrated, the catalyst carrier  4  is formed by layers of sheet metal which are at least partially structured and are preferably intertwined in the form of an S. Other configurations of the catalyst carrier  4  are possible. The catalyst carrier may also be formed of a nonmetallic material, in particular of a ceramic. 
     The housing  1  is divided in a division plane E which runs essentially transversely to the longitudinal direction of the passages  8 . In the exemplary embodiment illustrated, the division plane E lies essentially in a plane of symmetry of the catalyst carrier  4 . However, this is not absolutely necessary. The housing may also be divided asymmetrically. 
     A flange  5  is provided between the first housing part  2  and the second housing part  3 . The flange  5  is disposed in the division plane E. The catalyst carrier  4  penetrates through the flange  5 . For this purpose, the flange  5  has a passage opening  13  which is adapted to the outer contour of the catalyst carrier  4 . The flange  5  extends through the housing  1  as far as the catalyst carrier  4 . 
     The metallic catalyst carrier  4  is at least partially connected to the first housing part  2  and the second housing part  3  of the housing  1 . The joint between the catalyst carrier  4  and the first housing part  2  or the second housing part  3  is preferably a soldered joint. Preferably, there is also a soldered joint between the flange  5  and the catalyst carrier  4 . In addition, or as an alternative, there may be a soldered joint between the flange  5  and the first housing part  2  and/or the second housing part  3  of the housing  1 . The joint between the flange  5  and the first housing part  2  and/or the second housing part  3  of the housing  1  may also be a material-to-material joint. The joint may be formed, by way of example, by welding, in particular by laser welding, friction welding, arc welding or resistance welding. 
     The flange  5  is essentially perpendicular to the longitudinal axis  12  of the catalyst carrier  4 . It is also configured to be essentially perpendicular to the housing  1 . Due to the fact that the flange  5  extends as far as the catalyst carrier  4 , there is a sharp-edged transition between the flange  5  and the housing  1 . This sharp-edged transition between the flange  5  and the housing  1  allows the catalyst carrier configuration to be positioned very accurately in the exhaust duct of an exhaust system. In particular, it is not absolutely necessary to machine the edge of an outlet passage on the cylinder. Due to the fact that the flange  5  projects into the housing  1 , the forces acting on the housing  1  from the catalyst carrier  4  are also introduced into the flange  5  via the housing  3 . In the exemplary embodiment illustrated, the end faces of the housing parts  2 ,  3  butt against the flange  5 . Via these end faces, a force which is acting on the catalyst carrier and is caused by the flowing exhaust gas is introduced into the flange  5 . This reduces the load on the connection between the flange  5  and the catalyst carrier  4  or between the flange  5  and the first housing part  2  and/or the second housing part  3  of the housing  1 . FIG. 3 shows an enlarged illustration of the connection region between the housing parts  2 ,  3  and the flange  5 . 
     The flange  5  has two bores  6 , through which attachment elements, in particular screws, can project, through the use of which elements the catalyst carrier configuration is connected to an exhaust system. The bores  6  lie on a common axis  10 . The flange  5  is configured as a seal which has at least one sealing surface  9 . 
     As can be seen in particular from FIG. 1, the catalyst carrier  4  has two passages or channels  14  which are formed at a distance from one another and have a larger cross section than the other passages or channels  8  of the catalyst carrier  4 . The passages  14  are formed essentially in the central region of the catalyst carrier  4 . In the case of the catalyst carrier  4  illustrated in FIG. 1, the passages  14  are formed in the regions in which winding spindles engage for producing the catalyst carrier  4 . The catalyst carrier is preferably produced in accordance with a method which is described in International Patent Publication WO 97/00725 or WO 97/00135. 
     FIGS. 4,  5  and  6  show a second exemplary embodiment of a catalyst carrier configuration. The catalyst carrier configuration has a two-part housing  1 . A catalyst carrier  4  is disposed in the housing  1 . The catalyst carrier  4  has a plurality of passages  8  which are separated from one another by partitions or partition walls  7 . The passages  8  extend in the longitudinal direction of the catalyst carrier. The partitions  7  may be formed by metal sheets which are at least partially structured. 
     The housing  1  is divided in a division plane E which runs essentially transversely to the longitudinal direction of the passages  8 , so that the housing  1  has a first housing part  2  and a second housing part  3 . Each housing part  2 ,  3  partially surrounds the catalyst carrier  4 . 
     A flange  5  is disposed between the first housing part  2  and the second housing part  3  of the housing  1 . The flange  5  is of platelike construction. It is disposed in the division plane E. The flange  5  has a passage opening  13  through which the catalyst carrier  4  extends. The form of the passage opening  13  essentially corresponds to the outer contour of the catalyst carrier  4 . The inner edge  15  of the passage opening  13  bears against the outer casing of the catalyst carrier  4 . The flange  5  is preferably soldered to the catalyst carrier  4 . 
     The flange  5  has sealing elements  11 , which are disposed on opposite surfaces, with sealing faces  9 . The sealing elements  11  end at a distance from the first housing part  2  and the second housing part  3 , as can be seen in particular from FIG.  6 . 
     The flange  5  is disposed between the housing parts  2 ,  3 , as illustrated by FIG.  6 . The mutually facing end faces of the housing parts  2 ,  3  bear against the flange  5 . The flange  5  extends as far as the catalyst carrier  4 . The flange  5  can be joined to the housing  1  or to the housing parts  2 ,  3  in the manner which has already been explained with reference to the first exemplary embodiment. 
     FIGS. 7,  8  show a further exemplary embodiment of a catalyst carrier configuration. The catalyst carrier configuration has a housing  1  which is of two-part construction. The housing  1  has a first housing part  2  and a second housing part  3 . The first housing part  2  and the second housing part  3  are of essentially tubular construction. A catalyst carrier  4  is disposed inside the housing  1 . The catalyst carrier  4  has a plurality of passages  8  which are separated from one another by partitions  7  and extend in the longitudinal direction of the longitudinal axis  12  of the catalyst carrier  4 . 
     In the exemplary embodiment illustrated, the catalyst carrier  4  is formed by layers of metal sheet which are at least partially structured and are intertwined essentially in the form of an S, as can be seen from FIG.  7 . Other configurations of the catalyst carrier  4  are possible. The housing  1  is divided in a division plane E which runs essentially transversely to the longitudinal direction of the passages  8 . In the exemplary embodiment illustrated, the division plane E lies essentially in a plane of symmetry of the catalyst carrier  4 . However, this is not absolutely necessary. 
     A flange  5  is formed between the first housing part  2  and the second housing part  3 . The flange  5  lies in the division plane E. The catalyst carrier  4  penetrates through the flange  5 . To this end, the flange  5  has a passage opening  13  which is adapted to the outer contour of the catalyst carrier  4 . 
     The flange  5  and the housing part  2  form a carrying unit  27 . The housing part  2  and the flange  5  are connected to the housing part  2 . The flange  5  is preferably soldered or welded to the housing part  2 . 
     As can be seen in particular from FIG. 9, the second housing part  3  lies at a certain distance in the axial direction from the flange  5 . 
     The metal catalyst carrier  4  is preferably at least partially connected to the first housing part  2  and the second housing part  3  of the housing  1 . The joint between the catalyst carrier  4  and the first housing part  2  or the second housing part  3  is preferably a soldered joint. There is preferably also a soldered joint between the flange  5  and the catalyst carrier  4 . 
     The flange  5  has two bores  6  through which attachment elements, in particular screws, can extend, through the use of which elements the catalyst carrier configuration can be connected to a cylinder head and/or a manifold of an internal combustion engine. The bores lie on a common axis  10 . 
     The flange  5  is of platelike construction. It preferably forms a seal which has at least one sealing surface  9 . 
     As can be seen in particular from FIG. 7, the catalyst carrier  4  has two main passages  14  which are formed at a distance from one another and have a larger cross section than the other passages  8  in the catalyst carrier  4 . The passages  14  are formed essentially in the central region of the catalyst carrier  4 . In the case of the catalyst carrier  4  illustrated in FIG. 7, the main passages  14  are formed in the regions in which winding spindles engage for the purpose of producing the catalyst carrier  4 . The catalyst carrier is preferably produced in accordance with the method which is known from International Patent Publication WO 97/00725 or WO 97/00135. 
     FIG. 10 is a full sectional view of a further exemplary embodiment of a catalyst carrier configuration. The catalyst carrier configuration has a catalyst carrier  4 . The catalyst carrier body  4  has a plurality of passages  8  which are separated from one another by partition walls  7  and extend in the longitudinal direction of the longitudinal axis  12  of the catalyst carrier. 
     The housing  1  surrounds the catalyst carrier  4 . The housing  1  has an extent in the longitudinal direction of the catalyst carrier  1  which is smaller, in particular significantly smaller, than the length of the catalyst carrier  4 . 
     The housing  1  is of annular construction. The housing  1  is connected to a flange  5  which, together with the housing  1 , forms a carrying unit  27 . The flange  5  as such may form a seal. 
     The flange  5  has a passage opening  13  through which the catalyst carrier  4  extends. A section  43  which is adjacent to the passage opening  13  projects into the housing  1 . The housing  1  has a continuous, encircling recess  44 , into which the section  43  projects. In the exemplary embodiment illustrated the recess  44  is in the form of a step, as can be seen from FIG.  11 . The recess  44  is delimited by two faces or surfaces which run essentially perpendicular to one another and against which the flange  5  bears. The transition region between the flange  5  and the housing  1  is sharp-edged, so that the catalyst carrier configuration is able to adopt a predefined installation position. The flange  5  is preferably joined to the housing  1  through the use of a soldered joint. As an alternative, the flange  5  may be joined to the housing  1  by welding. The soldered joint between the flange  5  and the housing  1  may be formed at the same time as a soldered joint between the housing  1  and the catalyst carrier. In order to ensure that the flange  5  does not leave its predetermined position when handling the unsoldered catalyst configuration, it is suggested to connect the flange  5  to the housing  1  in a force-fitting and/or form-fitting manner. 
     In addition to the housing  1  illustrated in FIG. 10, at least one housing part may be provided at a distance from the housing  1 . Such an configuration is expedient in particular if the catalyst carrier  4  is a metallic catalyst carrier which is wound in the form of an S. 
     FIGS. 12,  13  and  14  show a further embodiment of a catalyst carrier configuration. The catalyst carrier configuration has a single-part housing  1 . A catalyst carrier or catalyst carrier body  4  is disposed in the housing  1 . The catalyst carrier  4  has a plurality of passages  8  which are separated from one another by partitions  7 . The passages  8  extend in the longitudinal direction of the catalyst carrier. The partitions  7  may be formed by metal sheets which are at least partially structured. 
     The catalyst carrier configuration has a flange  5 . A section  43  of the flange  5  projects partially into the housing  1 . The housing  1  has a recess  46  in its outer wall  45 . The section  43  of the flange  5  projects into the recess  46 . The recess  46  is formed by a groove. The groove  46  is configured so as to run in a continuous manner, in other words uninterrupted, around the circumferential direction of the housing  1 . 
     The joint, which is illustrated in particular in FIG. 14, between the flange  5  and the housing  1  may also be formed by dividing the housing  1  in the region of the recess  46 . 
     The section  43  of the flange  5  is preferably introduced into the recess  46  in the housing  1  by providing the external diameter of the housing  1 , in the uninstalled state of the housing  1 , with a smaller diameter than the internal diameter of the passage opening  13 , preferably a little smaller than the internal diameter of the passage opening  13  of the flange  5 . The flange  5  is positioned in the region of the recess  46 . Then, the housing  1  is widened at least in the region of the recess  46 , so that the section  43  of the flange  5  passes into the recess  46 . The housing  1  may be widened, by way of example, by plastic deformation of the housing  1 . This plastic deformation can be achieved by mechanically acting on the housing  1 . The housing  1  can also be widened by applying a pressurized medium, in particular air, to the internal chamber of the housing  1 . 
     In the exemplary embodiment illustrated, the flange  5  has sealing elements  11  which are disposed on both sides of the flange  5 . The sealing elements  11  end at a distance from the first housing part and the second housing part  3 , as is illustrated in particular in FIG.  14 . 
     The axial extent of the housing  1  essentially corresponds to the axial extent of the catalyst carrier  4 . This is however not obligatory. The axial extent of the individual housing parts or both housing parts  2 ,  3  may also be less than the axial extent of the catalyst carrier  4 . The catalyst carrier  4  may also project out of the housing  1 . 
     FIGS. 15 to  17  show a further exemplary embodiment of a catalyst carrier configuration. The catalyst carrier configuration includes a housing  1  and a flange  5 . A catalyst carrier  4  is disposed in the housing  1 . The catalyst carrier  4  has a plurality of passages which are separated from one another by partitions  7  and extend in the axial direction of the catalyst carrier  4 . The partitions  7  extend essentially in the longitudinal direction of a longitudinal axis  12  of the catalyst carrier  4 . FIG. 15 shows that the catalyst carrier  4  is formed essentially in the form of an S. It is formed by a plurality of layers of metal sheet which are at least partially structured. 
     The flange  5  extends essentially radially outward. It is of essentially platelike construction. In the exemplary embodiment illustrated, the flange  5  has two bores through which suitable attachment devices, in particular screws, can extend. Through the use these attachment devices the catalyst carrier configuration is connected to an exhaust system. The bores  6  lie on a common axis  10 . However, this is not absolutely necessary. On its opposite faces, the flange  5  has sealing elements  11 . The sealing elements have sealing surfaces  9 . The seals  11  form a gastight connection between the exhaust system and the catalyst configuration and between a housing of an engine, in particular an internal combustion engine. 
     The flange  5  has a passage bore  13  through which the housing  1  extends. The flange  5  has a section  43  which is adjacent to the passage bore  13 . The section  43  of the flange  5  extends partially into the housing  1 . On its outer wall  45 , the housing  1  has a recess  47 . The section  43  projects into the recess  47 . The recess  47  is formed by swaged or stamped sections  48  which are directed radially outward. In the exemplary embodiment illustrated, the swaged sections  48  are formed on both sides of the flange  5 . The swaged sections are in the form of beads. They may also be configured in the form of nubs or in some other way. The swaged or stamped sections may be formed by rams, stamping machines or the like. 
     FIG. 18 shows a structural unit  25  having a plurality of housings  1  which have a common flange  5 . The flange  5  is connected to the housings  1 . The flange  5  is formed essentially transversely to the longitudinal extent of the housings  1 . 
     In the exemplary embodiment illustrated in accordance with FIG. 18, each housing  1  is of oval construction. Other cross sections of the housings  1  are possible. It is not absolutely necessary for each housing  1  to have the same cross section. The cross sections of the housings  1  may be differently adapted to one another and the distance between the housings  1  may vary. The layout of the cross sections of the housings and their configuration relative to one another is determined essentially by the geometry of an internal combustion engine, in particular on the configuration of the outlet passages and the number of the outlet passages. In the exemplary embodiment illustrated, four housings  1  which are spaced apart from one another are provided. 
     The flange  5  is preferably configured in such a way that the opposite side faces  34 ,  35  in each case form a sealing surface. The side faces  34 ,  35  are used to connect the structural unit  25  in a sealed manner between a cylinder head and a manifold of an internal combustion engine. 
     It can be seen in particular from FIG. 18 that the side face  34  has a sealing surface  39  which is of a continuous, encircling construction. Each housing  1  is disposed inside that surface of the flange  5  which is delimited by the sealing surface  39 . As an alternative, each housing  1  may be surrounded by at least one sealing surface. Instead of forming a sealing surface directly on the flange  5 , it is also possible to use a sealing element which comes to bear against the collar  5 . 
     In order to join the structural unit  25  to a cylinder head and/or a manifold of an internal combustion engine, the flange  5  has bores  6 , through each of which a connecting element, for example, a screw or a threaded pin, can extend. 
     Preferably, each housing  1  has a stop  38  which projects into a chamber  28  in the housing  1 . The stop  38  is preferably of annular configuration. The stop  38  may also be configured in the form of projections. The stop  38  is used to fix a catalyst carrier which is disposed in the chamber  28  in the housing  1 . 
     In order to fix the flange  5  to a cylinder head or a manifold, the flange  5  has bores  6  through which, by way of example, a screw can extend. 
     A catalyst carrier  4  is disposed in each housing  1 . The longitudinal extent of the catalyst carrier  4  preferably corresponds to the axial length of the housing  1 . In the exemplary embodiment illustrated, the catalyst carrier  4  is a metallic honeycomb body which includes smooth metal sheets  29  and structured metal sheets  30 , which between them delimit passages  8  for an exhaust gas. The catalyst carriers  4  extend on both sides of the flange  5 . 
     As an alternative to a metallic catalyst carrier, it is also possible to use a ceramic catalyst carrier. In the case of such a use of a ceramic catalyst carrier, an insulating mat is provided between the catalyst carrier and the housing, with the result that different thermal expansions of the honeycomb body in the structural unit are compensated. 
     The catalyst carrier configuration according to the invention is particularly suitable for installation close to the engine. FIG. 19 shows the catalyst carrier configuration illustrated in FIG. 2 in the installed position. A cylinder head  16  of an internal combustion engine has an outlet passage  17 . The opening of the outlet passage  17  is surrounded by a sealing surface  18 . 
     A catalyst carrier  4  partially projects into the outlet passage  17 . The catalyst carrier  4  is provided in a two-part housing  1 . That section  40  of the catalyst carrier  4  which is provided in the carrying unit  27  formed by the flange S and the first housing part  2  projects into the outlet passage  17 . The flange  5  bears against a sealing surface  18  of the cylinder head  16 . The flange  5  is configured as a metallic seal. Threaded bolts  19  extend through the openings  6  in the flange  5 . 
     The second housing part  3 , together with that section  41  of the catalyst carrier  4  which is provided in the second housing part  3 , projects into an exhaust duct  21  of the manifold  20 . The exhaust duct  21  forms an exhaust-gas flow path  42  for an exhaust gas from the internal combustion engine. 
     The manifold  20  has a connection piece  22 . The connection piece  22  has bores  23  which are of corresponding construction to the bores  6  of the flange  5 . Threaded bolts  19 , which are connected to the cylinder head  16 , extend through the bores  6  of the flange  5  and the bores  23  of the connection piece  22 . In order to fix the manifold  20  and the flange  5  on the cylinder head  16 , nuts  24  are screwed onto the threaded bolts  19 . 
     As has already been explained above, the flange  5  is configured in the form of a metallic seal. This configuration of the flange  5  produces a gastight connection between the cylinder head  16  and the manifold  20 . For this purpose, the flange  5  bears against the sealing surface  18  of the cylinder head  16 . The connection piece  22  also has a sealing surface  26 , which comes to bear against the flange  5 . The manifold  20 , together with the catalyst carrier configuration, forms part of an exhaust system of an internal combustion engine. 
     If an internal combustion engine has a plurality of outlet passages  17 , a catalyst carrier configuration may be positioned in each outlet passage.