Abstract:
A catalytic conventer assembly is provided that includes a metallic tubular member having a first end and a second end. The metallic tubular member includes an aperture centrally formed between the first end and the second end. A sensor is received in the aperture and extends into an interior of the metallic tubular member for sensing a content of gas flowing through the metallic tubular member. At least one substrate is disposed within the metallic tubular member. The at least one substrate has a cavity formed in an exterior surface of the at least one substrate and extends radially inward. The cavity is aligned with the aperture of the metallic tubular member and receives a portion of the sensor extending into the interior of the metallic tubular member.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    Not Applicable 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable 
       REFERENCE TO A SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX 
       [0003]    Not Applicable 
       BACKGROUND OF THE INVENTION 
       [0004]    1. Field of Invention 
         [0005]    This invention relates in general to catalytic converters, and more specifically, to catalytic converters with a mid-bed sensor. 
         [0006]    2. Background of Related Art 
         [0007]    Catalytic converters include one or more catalytic elements or substrates housed in a metallic housing. The housing includes a first end and a second end. Each end portion may be conical-shaped. The catalytic converters are typically manufactured by cutting a metallic tubular member to a desired length. A respective support element is disposed around a respective substrate and thereafter inserted within the housing. The housing is formed to a targeted dimension for securing the substrates therein. One or more respective substrates may be utilized within a respective catalytic converter. Substrates are typically secured by some means to prevent movement of the substrate within the housing such as press forming the housing and support member against the outer surface of the substrate. Two substrates utilized in a catalytic converter closely positioned next to one another are less susceptible to movement or tilting after the substrates are secured within the housing by deforming the housing radially inward. However, in certain instances, the substrates are required to be spaced from each other and may be subject to movement or tilting even though the housing and support member has been secured against the substrate. 
         [0008]    One example is when a sensor is utilized. Sensors are commonly coupled to the housing for sensing gas content passing through the substrates. The sensor is inserted through the wall of the housing and extends into the interior air space between the spaced apart substrates. The aperture for receiving the housing is typically disposed equidistant between the ends of the housing so that the sensor is positioned between the substrates. 
         [0009]    Moreover, design constraints may dictate that the length of the converter is shorter than what is desired to secure the substrates therein. Under such conditions, the axial length of the both substrates may be shortened to accommodate the shorter design packaging. The substrates will have a greater tendency to move and tilt as the axial length of each respective substrate gets substantially equal to or less than diameter of each respective substrate. The securing of the housing and support member against the substrates may not prevent movement or tilting of the respective substrates under such conditions. There is often a trade-off that must be made between spacing required to accommodate the sensor therebetween and the length of the substrates that must be used to prevent tilting of the substrate. Moreover, when packaging is not a concern, additional length may be added to each substrate and the housing to prevent the tilting issues discussed earlier, but such additional material adds material cost to the substrate and housing. 
       BRIEF SUMMARY OF THE INVENTION 
       [0010]    The present invention has an advantage of utilizing a cavity formed in at least one substrate of a catalytic converter to receive a mid-bed sensor for monitoring gas content flowing through the catalytic converter. The cavity eliminates the typical space formed by a pair of substrates spaced apart from one another for receiving the sensor therebetween. The cavity allows the substrates to be packaged close to one another thereby maintaining a desired length of the substrates to prevent tilting of the substrates. This also has the advantage of reducing the overall axial length of the catalytic converter housing that house the substrates therein. 
         [0011]    In one aspect of the present invention, a catalytic converter assembly is provided that includes a metallic tubular member having a first end and a second end. The metallic tubular member includes an aperture centrally formed between the first end and the second end. A sensor is received in the aperture and extends into an interior of the metallic tubular member for sensing a content of gas flowing through the metallic tubular member. At least one substrate is disposed within the metallic tubular member. The at least one substrate has a cavity formed in an exterior surface of the at least one substrate and extends radially inward. The cavity is aligned with the aperture of the metallic tubular member and receives a portion of the sensor extending into the interior of the metallic tubular member. 
         [0012]    In yet another aspect of the present invention, a method is provided for forming a catalytic converter assembly having at least one substrate. A metallic tubular member is provided having a first end and a second end. The metallic tubular member has an aperture centrally formed between the first end and the second end and adapted to receive a sensor. The at least one substrate is inserted within the metallic tubular member. The at least one substrate has a cavity formed in an exterior surface of the at least one substrate and extends radially inward. The cavity is aligned with the aperture. The sensor extends through the aperture into an interior of the metallic tubular member to be received by the cavity formed in the at least one sensor. The sensor is secured to the metallic tubular member. 
         [0013]    Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a cross section view of a prior art catalytic converter assembly. 
           [0015]      FIG. 2  is a cross section view of a catalytic converter assembly according to a first preferred embodiment. 
           [0016]      FIG. 3  is a perspective view of the substrates of the catalytic converter assembly according to the first preferred embodiment. 
           [0017]      FIG. 4  is a top view of the substrates of the catalytic converter assembly according to the first preferred embodiment. 
           [0018]      FIG. 5  is a method for assembling a catalytic converter assembly according to the first preferred embodiment. 
           [0019]      FIG. 6  is a cross section view of a catalytic converter assembly according to a second preferred embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0020]    Referring now to the drawings, there is illustrated in  FIG. 1 , a cross section view of a catalytic converter assembly  10 . The catalytic converter assembly  10  includes a metallic tubular member that forms a housing  12 . The metallic tubular member is produced from a corrosion resistant alloy such as a stainless steel alloy having a first end  11  and a second end  13 . The first end  11  and the second end  13  may include tapered or conical-shaped ends (not shown). 
         [0021]    A first catalytic element  14  comprises a first substrate  16  and a first support member  18  secured within an interior of the housing  12 . An inner surface  20  of the housing  12  is pressed against the first catalytic element  14  for securing the first catalytic element  14  therein. Alternatively, the first catalytic element  14  may be stuffed into the housing  12 . 
         [0022]    The catalytic converter assembly  10  further includes a second catalytic element  21 . The second catalytic element  21  comprises a second substrate  22  and a second support member  19  secured within an interior of the housing  12 . An inner surface  20  of the housing  12  is pressed against the second catalytic element  21  for securing the second catalytic element  21  therein. Alternatively, the second catalytic element  21  may be stuffed into the housing  12 . 
         [0023]    The catalytic converter assembly  10  may further include a sensor boss  24 . The sensor boss  24  is inserted through a housing aperture  26 . The sensor boss  24  is secured to the housing  12 . The sensor boss  24  receives a sensor  28  for measuring the gas content passing through the substrates. Due to the spacing  27  (i.e., gap width) between the respective substrates, movement or tilting of the respective substrates may occur during operation of the catalytic converter, and more so when a shortened substrate (e.g., axial length substantially equal to or less than the diameter of the substrate) is utilized which may lead to damage of the substrates and degradation of the operation of the catalytic converter. 
         [0024]      FIG. 2  illustrates a cross section view of a catalytic converter assembly  40  according to a first preferred embodiment. The catalytic converter assembly  40  includes the first substrate  42  and the second substrate  44  juxtaposed to one another. A first support member  18  is disposed between the inner surface  20  of the housing  45  and the first substrate  42 . The second support member  19  is disposed between the inner surface  20  of the housing  45  and the second substrate  44 . A sensor cavity  46  is formed between the first substrate  42  and the second substrate  44  for receiving the sensor  28  therein. 
         [0025]      FIG. 3  illustrates perspective views of the first substrate  42  and the second substrate  44  according to the first preferred embodiment. The first substrate  42  includes a first partial cavity  48  that is disposed at a first end  51  of the first substrate  42 . Preferably, the first partial cavity  48  is formed by a high speed drilling operation which creates a bore through an exterior circumferential surface  49  of the first substrate  42 . Alternatively, other processes may be used for form the cavity including, but not limited to a cutting operation. The first partial cavity  48  is open-ended to the first end  51  of the first substrate  42  as well as the exterior circumferential surface  49  of the first substrate  42  for forming a first half of the sensor cavity  46  (shown in  FIG. 2 ). 
         [0026]    The second substrate  44  includes a second partial cavity  50  that is disposed at a first end  52  of the second substrate  44 . Preferably the second partial cavity  50  is formed by a high speed drilling operation which creates a bore through an exterior circumferential surface  53  of the first substrate  44 . Alternatively, other processes may be used for form the cavity including, but not limited to a cutting operation. The second partial cavity  50  is open-ended to the second end  52  of the second substrate  44  as well as the exterior circumferential surface  53  of the second substrate  44  for forming a second half of the sensor cavity  46 . 
         [0027]    Referring to both  FIG. 2  and  FIG. 3 , as the first substrate  42  and the second substrate  44  are assembled within the housing  45  into a juxtaposed position, the first substrate  42  and the second substrate  44  are angularly aligned for aligning the first partial cavity  48  and the second partial cavity  50  for forming the sensor cavity  46 . The first partial cavity  48  and the second partial cavity  50  may either be aligned prior to being inserted within the housing  45  or the substrates may be rotated as required after each substrate is assembled for aligning the first partial cavity  48  and second partial cavity  50  to form the sensor cavity  46 . The first partial cavity  48  and the second partial cavity  50  must be in radial alignment with the aperture  26  formed in the housing  45  for receiving the sensor  26  therethrough. 
         [0028]    The formation of the sensor cavity  46  within the first substrate  42  and the second substrate  44  permits the first substrate  42  and the second substrate  44  to be positioned closer to one another which allows the overall axial length of the catalytic converter assembly  40 , specifically the housing  45 , to be shortened. The advantage is the shortened catalytic converter assembly  40  provides for a reduced packaging space in a vehicle; provides for a reduction of the material required for producing the housing; provides added support and prevents tilting of the substrates. 
         [0029]      FIG. 4  illustrates a top view of the first substrate  42  and the second substrate  44  according to a first preferred embodiment. The first substrate  42  and the second substrate  44  are assembled such that there is a reduced gap width  54  between the respective substrates. The gap width  27  between the first substrate  16  and the second substrate  22  of a prior art catalytic converter assembly (as shown in  FIG. 1 ) is of a width in that is larger than a width of the sensor  26 . In  FIG. 4 , the positioning of the first substrate  42  closer to the second substrate  44  as a result of the cavity  46  allows the gap width  54  (i.e., spacing) to be substantially narrowed. The gap width  54  may be narrowed to any predetermined gap width that is less than that shown in  FIG. 1  including a 0 mm gap width which prevents movement/tilting of the respective substrates. 
         [0030]      FIG. 5  illustrates a method of assembling the catalytic converter according to the first preferred embodiment. In step  60 , a metallic tubular member is provided having a first end and a second end. The tubular member includes an aperture formed between the first end and the second end and adapted to receive a sensor. In step  61 , at least one substrate is inserted within the metallic tubular member. The at least one substrate includes a sensor cavity formed in an exterior surface of the at least one substrate. The sensor cavity extends radially inward to a predetermined depth. In step  62 , the sensor cavity is radially aligned with the aperture of the metallic tubular member. If more than one substrate is utilized where partial cavities are formed on the end portions of each substrate, one or more of the respective substrates are rotated to angularly align the partial cavities for cooperatively forming the sensor cavity. In step  63 , a sensor is inserted through the aperture and into the sensor cavity formed by the at least one substrate for monitoring gas content during the operation of the vehicle. It must be understood that the method described above is only one embodiment of assembling the catalytic converter and the assembly of the catalytic converter may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope. 
         [0031]      FIG. 6  illustrates a catalytic converter assembly  80  according to a second preferred embodiment. The catalytic converter assembly  80  includes a single substrate  81  having a sensor cavity shown generally at  82 . The sensor cavity  82  extends radially inward to a predetermined depth and includes a profile similar to a profile of the sensor  28 . The substrate  81  may be radially aligned with the aperture  26  prior to being assembled within the housing  45  or may be rotated after assembly for alignment with the aperture  26 . The sensor cavity  82  is formed by one or more high speed drilling operations. For example, a first high speed drilling operation may produce a first bore  86 . Thereafter, a second high speed drilling operation is used to form the second bore  88 . Alternatively, other processes may be used for form the cavity including, but not limited to a cutting operation. It is noted that the sensor cavity  82  may include the other shapes and is not limited to the shape of the respective sensor as shown. 
         [0032]    In accordance with the provisions of the patent statutes, the principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.