Abstract:
A method is provided for manufacturing a catalytic converter housing arrangement with at least one sensor carrier for an exhaust system of a vehicle. The method includes the steps of:
       a) providing at least one sensor carrier sheet metal blank ( 42 );   b) forming at least one sensor mounting opening ( 48 ) in the sensor carrier sheet metal blank ( 42 ) by flow drilling such that a length (L) of the opening is greater than a thickness (D) of the material of the sensor carrier sheet metal blank ( 42 ) before step b) is carried out; and   c) preparing an internal thread in the at least one sensor mounting opening ( 48 ) for providing a sensor carrier.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of priority under 35 U.S.C. §119 of German Application 10 2015 121 110.6 filed Dec. 4, 2015, the entire contents of which are incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The present invention pertains to a method for manufacturing a catalytic converter housing arrangement with at least one sensor carrier for an exhaust system of a vehicle. 
       BACKGROUND OF THE INVENTION 
       [0003]    US 2007/00178026A1discloses a catalytic converter arrangement, on which a sensor carrier for a sensor, for example, for a gas sensor, may be provided. This catalytic converter arrangement is shown in  FIG. 1  and is generally designated by  10 . It comprises a catalytic converter housing arrangement  12  with a tubular, i.e., essentially cylindrical housing central area  14 , which is, for example, configured with a circular cross section, and with a conical housing end area  16 ,  18  each located at the two end areas thereof. A catalytic converter housing  19  of the catalytic converter housing arrangement  12  is manufactured of a sheet metal material with the housing central area  14  and with the housing end areas  16 ,  18 . Two catalytic converter units  20 ,  22  are provided in the interior space of the catalytic converter housing  19 . Each catalytic converter unit  20 ,  22  comprises a catalytic converter block  24 ,  26 , which has, for example, a monolithic configuration, and a mounting mat  28 ,  30 , which surrounds this block  24 ,  26  and is mounted in the housing central area  14  by press fit. The exhaust gases discharged by an internal combustion engine can enter the catalytic converter arrangement  10  via an opening  32  of the housing end area  16 . The exhaust gases can leave the catalytic converter arrangement  10  via an opening  34  of the housing end area  18 . 
         [0004]    An attachment  36 , which is, for example, ring-shaped and at which a sensor carrier configured as an internal thread can be fixed by welding, is provided at the housing central area  14 . A sensor, for example, a gas sensor, can be screwed into the sensor carrier and thus it can protrude into an intermediate space  40  formed between the two catalytic converter units  20 ,  22  through a sensor opening  38  provided on the catalytic converter housing  19  and thus detect there the gas composition, for example, the percentage of oxygen or the percentage of nitrogen. 
       SUMMARY OF THE INVENTION 
       [0005]    An object of the present invention is to provide a method with which a catalytic converter housing arrangement, which makes it possible to reliably mount at least one sensor in a simple manner, can be manufactured for an exhaust system of a vehicle. 
         [0006]    This object is accomplished according to the present invention by a method for manufacturing a catalytic converter housing arrangement with at least one sensor carrier for an exhaust system of a vehicle, comprising the steps of: 
         [0000]    a) providing at least one sensor carrier sheet metal blank;
 
b) forming at least one sensor mounting opening in the sensor carrier sheet metal blank by flow drilling such that an opening length is greater than the material thickness of the sensor carrier sheet metal blank before step b) is carried out (the sensor carrier sheet metal blank has an initial material thickness and the opening length of the formed sensor mounting opening is greater than the carrier sheet metal blank initial material thickness); and
 
c) preparing an internal thread in the at least one sensor mounting opening for providing a sensor carrier.
 
         [0007]    An accumulation of material in the area surrounding the opening is also brought about at the same time during the preparation of this opening with the method according to the present invention due to the formation of at least one sensor mounting opening by flow drilling. Thus, the opening has an opening length that is greater than the initial thickness of the sensor carrier sheet metal blank, so that material is made available for preparing a sufficiently long internal thread. 
         [0008]    The method according to the present invention may comprise, furthermore, the following steps: 
         [0000]    d) providing a catalytic converter housing, preferably one made of sheet metal material, with at least one sensor opening; and
 
e) fixation of at least one sensor carrier sheet metal blank or sensor carrier on the catalytic converter housing before step b) is carried out or after step c) or after step b) and prior to step c).
 
         [0009]    Consequently, the sensor carrier sheet metal blank can already be fixed with this procedure before the preparation of an opening in it or before the preparation of the internal thread on the catalytic converter housing arrangement. As an alternative, the finished sensor carrier, i.e., the sensor carrier already provided with opening and thread, can be fixed on the catalytic converter housing arrangement. Depending on the manner of further processing, the catalytic converter housing may already have been provided as a housing composed of a plurality of parts or areas, or it may be provided for the further processing, especially also for arranging one or more sensor carriers or sensor carrier sheet metal blanks, such that individual parts are not yet assembled into a housing. 
         [0010]    To make it possible to guarantee a stable and gas-tight arrangement of a sensor carrier on the catalytic converter housing, it is proposed that step e) comprise the fixation by welding. 
         [0011]    Provisions may now be made, for example, for step e) to comprise the placing of at least one sensor carrier sheet metal blank or sensor carrier on an outer surface of the catalytic converter housing and the fixation by fillet welding. As an alternative, provisions may be made for a flush transition of the sensor carrier to the outer surface of the catalytic converter housing for step e) to comprise the insertion of at least one sensor carrier sheet metal blank or sensor carrier in a sensor carrier depression formed on the catalytic converter housing in the area of a sensor opening and fixation by I-profile seam welding. 
         [0012]    Step d) may comprise the provision of the catalytic converter housing with an essentially cylindrical housing central area and, at at least one end of the housing central area, with an essentially conical housing end area, or/and the provision of the catalytic converter housing with at least one sensor opening in the housing central area. In particular, manufacture from a sheet metal material can be carried out simply and cost-effectively and it makes it possible to connect one or more sensor carriers by welding in a stable manner. 
         [0013]    Step d) may comprise, further, the provision of the catalytic converter housing with at least one sensor opening in at least one housing end area or/and the provision of the catalytic converter housing with at least one sensor opening in at least one transition area from the housing central area to a housing end area. 
         [0014]    The present invention pertains, furthermore, to a catalytic converter arrangement for an exhaust system of a vehicle, comprising a catalytic converter housing arrangement manufactured according to a method according to the present invention. 
         [0015]    At least one sensor is preferably carried by thread meshing (engagement) at at least one sensor carrier fixed on the catalytic converter housing arrangement. The thread meshing makes it possible, on the one hand, to connect a sensor in a stable manner and, on the other hand, in a gas-tight manner to the catalytic converter housing arrangement via the sensor carrier. 
         [0016]    At least one sensor being carried on the catalytic converter housing arrangement may be a gas sensor, preferably an O 2 , sensor or NO x  sensor, or/and at least one sensor being carried on the catalytic converter housing arrangement may be a temperature sensor. Consequently, a plurality of sensors, for example, different sensors, may, in principle, be carried on the catalytic converter housing arrangement in different positions in order to make it thus possible to provide comprehensive information on the state or the composition of the combustion waste gases. 
         [0017]    At least one catalytic converter unit may be carried in the catalytic converter housing arrangement. 
         [0018]    The present invention will be described in detail below with reference to the attached figures. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    In the drawings: 
           [0020]      FIG. 1  is a longitudinal sectional view of a catalytic converter arrangement known from the state of the art; 
           [0021]      FIG. 2  is a sectional view of a sensor carrier sheet metal blank; 
           [0022]      FIG. 3  is the sensor carrier sheet metal blank according to  FIG. 2  when the flow drilling operation is being carried out; 
           [0023]      FIG. 4  is the flow drilled sensor carrier sheet metal blank during a thread-cutting operation; 
           [0024]      FIG. 5  is a sensor carrier on a catalytic converter housing with a sensor being carried thereon; 
           [0025]      FIG. 6  is a sensor carrier fixed on a catalytic converter housing with a fillet weld; 
           [0026]      FIG. 7  is a sensor carrier fixed on a catalytic converter housing with an I-profile weld; 
           [0027]      FIG. 8  is a sensor carrier fixed in the area of a housing central area; 
           [0028]      FIG. 9  is a sensor carrier fixed in a transition area from a housing central area to a housing end area; and 
           [0029]      FIG. 10  is a sensor carrier fixed in a housing end area. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0030]    Referring to the drawings, it should be noted, before a method for manufacturing a catalytic converter housing arrangement, especially a sensor carrier, will be described in detail below, that the configuration of a catalytic converter housing arrangement to be manufactured in this manner or of a catalytic converter arrangement comprising same may, in principle, be such as it is shown in  FIG. 1  described above with reference to  FIG. 1 . Therefore, using the reference numbers already used in the introduction, reference will also be made in the context of the present invention to the general configuration of such a catalytic converter housing arrangement or catalytic converter arrangement as it is shown in  FIG. 1 . 
         [0031]      FIG. 2  shows a sensor carrier sheet metal blank  42  generally designated by  42  in contact with an outer surface  44  of the catalytic converter housing  19 , here of the housing central area  14 . The sensor carrier sheet metal blank  42  may be provided as an initially essentially flat component, for example, by punching or cutting out of a basic sheet metal material, for example, a metal sheet, and then transformed to the shape desired for the subsequent use, e.g., by pressing, bending or deep-drawing. The sensor carrier sheet metal blank  42  is thus provided with an edge area  46  shaped for being in contact with the catalytic converter housing  19  such that this edge area  46  can be in contact with the outer surface  44  in the entire area surrounding the sensor opening  38 . 
         [0032]    In a then following working step, shown in  FIG. 3 , a sensor mounting opening  48  is prepared in the sensor carrier sheet metal blank  42  by flow drilling. Flow drilling, generally also known as “thermal friction drilling,” is carried out with the use of a mandrel-like tool  50  heating to a high temperature and rotating about its longitudinal axis. The tool  50  is pressed against the sensor carrier sheet metal blank  42 . The metallic material of the sensor carrier sheet metal blank  42  is locally melted in the process in the area acted on by the tool  50  displaced to the side. An area of thickened material  52  surrounding the sensor mounting opening  48  is formed in the process on both sides of the sensor carrier sheet metal blank  42 , so that the sensor mounting opening  48  passing through this area of thickened material  52  has an opening length L that is greater than the initial thickness D of the sheet metal material of the sensor carrier sheet metal blank  42 . The sensor carrier sheet metal blank  42  may also be prepared with an essentially flat contact surface  54  for a sensor by the tool  50  in the area of thickened material  52  during the flow drilling. As will be shown below, the contact surface  54  is located on the outer side in the prepared catalytic converter housing arrangement  12 . 
         [0033]    In a next working step, shown in  FIG. 4 , an internal thread is cut in the sensor mounting opening  48  formed in the area of thickened material  52 . The internal thread  56  may be prepared by a corresponding tool  58  immediately after preparation of the sensor mounting opening  38  in the still hot state of the sensor carrier sheet metal blank  42 , or it may be prepared when the sensor carrier sheet metal blank  42  has already essentially cooled down. 
         [0034]    The sensor carrier sheet metal blank  42  is essentially finished after preparation of the internal thread  56 , so that a sensor carrier generally designated by  60  is provided. This is fixed by welding in a working step shown in  FIG. 5  with its edge area  46  on the outer surface  44  of the catalytic converter housing  19 , of the housing central area  14  in the example being shown. In case of fixation by welding in the manner shown in  FIGS. 5 and 6 , the edge area  46  is placed on the outer surface  44 , which is essentially free from steps, but is curved because of the tubular configuration of the housing central area  14 . A weld  62 , which surrounds the entire edge area  46  and thus connects this area to the catalytic converter housing  19 , can be prepared by fillet welding in the angular transition area between the edge area  46  and the outer surface  44 . A stable and especially gas-tight connection is thus established between the sensor carrier  60  and the catalytic converter housing  19 . 
         [0035]    A sensor generally designated by  64  can then be screwed into the sensor carrier  60 , so that an external thread  66  provided thereon meshes with the internal thread  56 . The sensor  64  can be screwed in to the extent that a stop  68  provided on it, for example, as a hexagon insert bit comes into gas-tight contact with the contact surface  54  of the sensor carrier  60 , optionally via the intermediary of a ring-shaped sealing element. 
         [0036]    When the sensor carrier  60  is manufactured or fixed, the different working steps described above may also be carried out in another chronological sequence. For example, after preparing the sensor carrier sheet metal blank  42  with the desired shape, this may be fixed to the catalytic converter housing  19  by welding. The sensor mounting opening  48  can then be prepared by flow drilling, and the internal thread  56  is then prepared in said opening. As an alternative, the sensor carrier sheet metal blank  42  could also be fixed on the catalytic converter housing  19  by welding when the sensor mounting opening  48  has been prepared in said sensor carrier sheet metal blank by flow drilling, but before the internal thread  56  is cut in the sensor mounting opening. 
         [0037]      FIG. 7  shows an alternative manner of connecting the sensor carrier  60  and the sensor carrier sheet metal blank  42 , depending on the sequence of the working steps, on the catalytic converter housing  19 . A sensor carrier depression  70  corresponding in its circumferential contour to the circumferential contour of the sensor carrier  60  and of the sensor carrier sheet metal blank  42  is provided on the catalytic converter housing  19 , for example, on the housing central area  14  in this variant. The sensor carrier  60  or the sensor carrier sheet metal blank  42  is inserted into this sensor carrier depression  70 , so that an intermediate space is left between the edge area  46  and a wall  72  surrounding the sensor carrier depression  70 . An I-profile weld  64 , also called two-sided full seam, which surrounds the entire edge area  46  and fills the intermediate space essentially completely, is prepared in this intermediate area. The edge area  46  of the sensor carrier  60  or of the sensor carrier sheet metal blank  42  thus passes essentially flush over into the outer surface  44  of the catalytic converter housing  19  essentially without a step, via the weld  74 . 
         [0038]      FIGS. 8-10  show different ways of positioning a sensor carrier  60  on the catalytic converter housing  19 . The positioning shown in  FIG. 8  also corresponds essentially to the position provided for a sensor carrier in case of the configuration shown in  FIG. 1 . The sensor opening  38  is provided in the housing central area  14 , especially in the area of the intermediate space  40  formed between the two catalytic converter units  20 ,  22 . A sensor to be fixed on the sensor carrier  60  can protrude into this intermediate space  40  and detect the composition of the gas or the temperature of the gas in this area. 
         [0039]    The sensor carrier  60  is provided in a transition area  76  between the housing central area  14  and, for example, the housing end area  18  in the embodiment according to  FIG. 9 . The sensor opening  38  is formed in this variant, for example, partly in the housing central area  14  and partly in the housing end area  18 . The edge area  46  of the sensor carrier  60  or of the sensor carrier sheet metal blank  42  is fixed, for example, by fillet welding on the outer surface  44  of the catalytic converter housing  19 . 
         [0040]    The sensor carrier  60  or the sensor carrier sheet metal blank  42  is provided, for example, entirely on the housing end area  18  in the embodiment variant shown in  FIG. 10 . The sensor opening  38  is arranged entirely in the conical area of the housing end area  18 . 
         [0041]    It is advantageous in case of the positioning of a sensor carrier  60  as shown in  FIG. 9  to connect the different areas or components of the catalytic converter housing  19 , i.e., the housing central area  14  and the housing end areas  16 ,  18 , to one another, for example, by welding and/or press fit before the sensor carrier  60  is placed on the transition area  76 . In the case of the positioning shown in  FIGS. 8 and 10 , the sensor carrier  60  can be fixed on the respective area or the respective component of the catalytic converter housing  19  before or after these areas or components of the catalytic converter hosing  19  are assembled. 
         [0042]    It should be noted that a plurality of sensor carriers  60  may be provided on the catalytic converter housing  19 . For example, at least one sensor carrier  60  each may thus be provided on each of the two housing end areas  16 ,  18  in order to be able to detect, for example, the composition of the gas or the gas temperature in the area located upstream of the two catalytic converter units  20 ,  22  and in the area located downstream of the catalytic converter units  20 ,  22 , or in order to be able to detect respective different measured variables in these areas. As an alternative or in addition, a plurality of sensor carriers  60  may also be provided on the housing central area  14 , for example, following one another in the circumferential direction. 
         [0043]    Further, a plurality of sensor mounting openings, for example, two sensor mounting openings, may be provided next to one another on at least one of the sensor carriers, so that a plurality of sensors, which are configured, for example, for detecting different measured variables, can be carried on a single sensor carrier. The sensor carrier, on the one hand, and, on the other hand, the sensor opening provided, associated with same, on the catalytic converter housing, can have correspondingly larger dimensions in this case. Further, sensor carriers of different shapes may be provided on one catalytic converter housing in order to guarantee, for example, the suitable installation position for the respective sensors to be arranged there, depending on the installation location. 
         [0044]    While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.