Abstract:
A mounting flange assembly for connecting adjoining exhaust components includes first and second pieces. One flange piece includes at least one first mount hole that extends in one direction and at least one second mount hole that extends in another direction. The first mount hole secures the first piece to one exhaust component and the second mount hole secures the first and second pieces together. Another exhaust component is attached to an opposite side of the first flange piece. The orientation of the first and second mount holes provides a sealed joint between the mating exhaust components while additionally providing improved service access.

Description:
TECHNICAL FIELD 
       [0001]    The subject invention relates to a mounting flange configuration for a vehicle exhaust component with improved serviceability access. 
       BACKGROUND OF THE INVENTION 
       [0002]    Exhaust systems are widely known and used with combustion engines. Typically, an exhaust system includes exhaust tubes that convey hot exhaust gases from the engine to other exhaust system components, such as converters, mufflers, resonators, etc. Each of the various exhaust components is mounted to an adjacent component at a mount interface. As such, each exhaust system includes a plurality of mount interfaces between adjoining components. 
         [0003]    One such example of a mount interface is the interface between a converter assembly and a cylinder head or manifold. Traditionally, this mount interface includes a flange mount member with a center opening that defines part of an exhaust gas flow path extending from the converter assembly and through an opening in the cylinder head. In one configuration, the flange mount member includes four mount holes that are used to fasten the flange mount member to the cylinder head. The converter assembly includes a tube portion that is connected to the flange mount member on an opposite side from the cylinder head. 
         [0004]    One disadvantage with this traditional configuration is that it is often difficult to perform service and maintenance operations. Specifically, it can be difficult to reach the lower two mount holes such that the converter assembly can be unfastened from the cylinder head. 
         [0005]    One proposed solution has been to provide a two-piece mount flange configuration. A first or lower flange piece includes two mount holes and is fastened to the cylinder head along a bottom edge of the opening in the cylinder head. A second flange piece includes a ring-shaped body with a center opening and a bottom edge that abuts against the lower flange piece at a location between the two lower mount holes. The ring-shaped body includes two upper mount holes that are used to fasten the second flange piece to the cylinder head near an upper edge of the opening in the cylinder head. The converter assembly is attached to the second flange piece. 
         [0006]    To service the converter assembly only the two upper fasteners, i.e. the two fasteners for the second flange piece, have to be removed. The first or lower flange piece remains fastened to the cylinder head. While this configuration improves serviceability, it introduces additional challenges. As the converter assembly is only secured to the cylinder head with two upper fasteners, there is not a good seal interface between the converter assembly and the cylinder head. As such, the use of the two-piece flange configuration with four bolts, only two of which are used to secure the converter assembly to the cylinder head, does not provide a tightly sealed joint, which is disadvantageous from a performance perspective. 
         [0007]    Thus, there is a need for a mount interface between exhaust components that provides improved serviceability while also providing a tightly sealed joint. 
       SUMMARY OF THE INVENTION 
       [0008]    A mount flange piece for connecting adjoining vehicle exhaust components includes first and second mount holes that extend in different directions to provide a tightly sealed joint, as well as providing easy serviceability. 
         [0009]    In one example, a mounting flange assembly for connecting first and second exhaust components together includes first and second pieces. The first piece includes at least one first mount hole that extends in a first direction and at least one second mount hole that extends in a second direction that is different from the first direction. The first piece is attached to the first exhaust component at the first mount hole. The second piece is separately attached to the first exhaust component, and the second piece is attached to the first piece via the second mount hole. 
         [0010]    In one example, the first piece comprises a ring-shaped body with a center opening that defines an exhaust gas flow path between the first and second exhaust components. The ring shaped body includes the first and second mount holes, with the first mount hole being used to secure the first piece to the first exhaust component. The second piece comprises a linear body portion that includes at least one third mount hole that is aligned with the second mount hole. The second piece also includes at least one fourth mount hole that is used to secure the second piece to the first exhaust component. The connection between the second and third mount holes pulls the first and second pieces together to provide a tightly sealed joint connection. 
         [0011]    In one example, the first and fourth mount holes extend in the first direction and are parallel to, and spaced apart from, each other. The second and third mount holes extend in the second direction and are coaxial with each other. In one example, the second direction is perpendicular to the first direction. 
         [0012]    In one example, the at least one first, second, third, and fourth mount holes comprise a pair of first mount holes, a pair of second mount holes, a pair of third mount holes, and a pair of fourth mount holes, respectively. 
         [0013]    One example assembly method is as follows. The linear body portion of the second piece is first fastened to the first exhaust component via the fourth mount holes. Then, the ring-shaped body is attached to the linear body portion via the interface between the second and third mount holes. Then, the ring-shaped body is attached to the first exhaust component via the first mount holes. The second exhaust component is attached to the ring-shaped body. In one example, the second exhaust component is attached to the ring-shaped body prior to attachment of the first and second pieces to the first exhaust component. 
         [0014]    The first piece, i.e. the ring-shaped body, with the associated second exhaust component can be easily removed from the first exhaust component by removing fasteners from the first and second mount holes while the second piece, i.e. the linear body portion, remains fastened to the first exhaust component. 
         [0015]    As such, the use of first and second pieces, along with the orientation of the first/fourth and second/third mount holes provides a sealed joint between the mating exhaust components while additionally providing improved service access. These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a perspective view of a portion of an exhaust system showing a mount interface between first and second exhaust components. 
           [0017]      FIG. 2A  is a perspective view of a first piece of the mount interface. 
           [0018]      FIG. 2B  is an end view of the first piece of  FIG. 2A . 
           [0019]      FIG. 2C  is a side view of the first piece of  FIG. 2A . 
           [0020]      FIG. 3A  is a perspective view of a second piece of the mount interface. 
           [0021]      FIG. 3B  is an end view of the second piece of  FIG. 3A . 
           [0022]      FIG. 3C  is a side view of the second piece of  FIG. 3A . 
           [0023]      FIG. 4A  is a perspective view of the first and second pieces secured together as viewed from a cylinder head or exhaust manifold side of the mount interface. 
           [0024]      FIG. 4B  is perspective view of the first and second pieces from  FIG. 4A  as viewed from a converter side of the mount interface. 
           [0025]      FIG. 4C  is a side view of  FIG. 4A . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0026]    An example of a portion of an exhaust system including a cylinder head mount area indicated generally at  10  is shown in  FIG. 1 . As known, the exhaust system is comprised of a plurality of components, converters, mufflers, resonators, etc., which convey hot exhaust gases from an engine to the external atmosphere. Each of the various exhaust components is mounted to an adjacent component at a mount interface. As such, each exhaust system includes a plurality of mount interfaces between adjoining components. 
         [0027]    An example of one such mount interface  12  is shown in  FIG. 1 , and is between a manifold or a cylinder head  14  of an engine  16  and a converter assembly  18 . The mount interface  12  comprises a flange attachment that is used to attach the converter assembly  18  directly to the cylinder head  14  to define an exhaust gas flow path. The mount interface  12  includes a first piece  20  that is attached to the cylinder head  14  and a separate, second piece  22  that is attached to the cylinder head  14  independently of the first piece  20 . The first  20  and second  22  pieces are also attached to each other. 
         [0028]    The converter assembly  18  includes a tube portion  24  that is attached to the first piece  20 . In one example, the tube portion  24  is welded to the first piece  20  as indicated at  26 . Due to the two-piece configuration, the first piece  20  and the associated converter assembly  18  can be removed from the cylinder head  14  without having to remove the second piece  22  from the cylinder head  14 . This improves serviceability of the exhaust system and will be discussed in greater detail below. Further, it should be noted that while the two-piece flange attachment mount interface is shown as being used between a cylinder head and a converter assembly, this attachment interface could also be used as an interface between other adjoining exhaust system components. 
         [0029]    The first piece  20  is shown in greater detail in  FIGS. 2A-2C . The first piece  20  includes a ring-shaped body  30  with a center opening  32  that defines a portion of the exhaust gas flow path between the cylinder head  14  and the converter assembly  18 . In the example shown, the center opening  32  has a non-circular cross-section; however, the opening could be defined by other cross-sectional shapes. 
         [0030]    The ring-shaped body  30  includes a first side  34  that faces the cylinder head  14  and an opposite second side  36  that faces the converter assembly  18 . The center opening  32  defines a centerline  38  of the exhaust gas flow path. The ring-shaped body  30  includes an upper edge portion  40 , a lower edge portion  42 , and side edge portions  44  that connect the upper  40  and lower  42  edge portions. The ring-shaped body  30  is further defined by a horizontal centerline  46  that intersects the centerline  38  of the exhaust gas flow path and a vertical centerline  48  that also intersects the centerline  38  of the exhaust gas flow path. 
         [0031]    Positioned above the horizontal centerline  46  are first  50  and second  52  mount holes that extend in a first direction that is generally parallel to the centerline  38  at the center opening  32 . The first  50  and second  52  mount holes are formed within first  54  and second  56  bosses that are formed in the upper edge portion  40  of the ring-shaped body  30 . The first  54  and second  56  bosses are positioned on opposite sides of the vertical centerline  48  from each other. 
         [0032]    Also positioned on opposite sides of the vertical centerline  48  from each other are third  58  and fourth  60  bosses. The third boss  58  includes a third mount hole  62  and the fourth boss  60  includes a fourth mount hole  64 . The third  62  and fourth  64  mount holes extend in a direction that is generally parallel to the vertical centerline  48 . As such, in this example, the first  50  and second  52  mount holes extend in a direction that is generally perpendicular to the third  62  and fourth  64  mount holes. 
         [0033]    As shown most clearly in  FIG. 2C , the ring-shaped body  30  is defined by a central plane P that extends in the direction of the vertical centerline  48  ( FIG. 2B ). The first  54  and second  56  bosses are generally centrally located relative to this central plane P. In the example shown, the third  58  and fourth  60  bosses include portions that extend out of the central plane P. 
         [0034]    The second piece  22  is shown in greater detail in  FIGS. 3A-3C . The second piece  22  includes a linear body portion  70  that extends in a direction that is generally parallel to the horizontal centerline  46 . The linear body portion  70  has a first end  72  with a first mount hole  74  and an opposite second end  76  with a second mount hole  78 . The first  74  and second  78  mount holes extend in a direction that is generally parallel to a direction in which the first  50  and second  52  mount holes of the first piece  20  extend, i.e. the first  74  and second  78  mount holes extend in a direction that is generally parallel to the centerline  38  at the center opening  32 . The first  74  and second  78  mount holes are used to attach the second piece  22  to the cylinder head. 
         [0035]    A first boss  80  is formed at the first end  72  of the linear body portion  70  and a second boss  82  is formed at the second end  76  of the linear body portion  70 . A third mount hole  84  is formed within the first boss  80  and a fourth mount hole  86  is formed within the second boss  82 . The third  84  and fourth  86  mount holes extend in a direction that is generally parallel to the third  62  and fourth  64  mount holes of the first piece  20 , i.e. the third  84  and fourth  86  mount holes extend in a direction that is generally parallel to the vertical centerline  48 . 
         [0036]    The first boss  80  includes a first flange portion  88  and the second boss  82  includes a second flange portion  90 . When the first  20  and second  22  pieces are attached to each other, one side of the third  58  and fourth  60  bosses of the first piece  20  abut against the second  90  and first  88  flange portions of the second piece  22 , respectively. In this position, the third  84  and fourth  86  mount holes of the second piece  22  are aligned with the fourth  64  and third  62  mount holes, respectively, of the first piece  20 . When these holes are aligned, fasteners  92  ( FIG. 4A-4C ) are used to secure the first  20  and second  22  pieces together. 
         [0037]    As the fasteners  92  are installed, the first  20  and second  22  pieces are drawn tightly together at corresponding abutment surfaces  94  to provide a tightly sealed connection joint as shown in FIGS.  1  and  4 A- 4 C. This is similar to mechanical pipe joint connections for attaching two adjoining flange portions of plumbing pipe together. 
         [0038]    The method of connecting the converter assembly  18  to the cylinder head  14  includes the following steps. First, the second piece  22  is attached to the cylinder head  14  by installing fasteners  96  ( FIG. 4A ) through the first  74  and second  78  mount holes of the linear body portion  70 . Next, the first piece  20  is attached to the second piece  22 . A bottom edge of the lower edge portion  42  of the first piece  20  rests against a horizontal ledge surface  98  of the linear body portion  70 . A vertical ledge surface  100  of the linear body portion  70  abuts against a corresponding abutment surface  110  on the second side  36  of the lower edge portion  42  of the ring-shaped body  30 . The third boss  58  of the first piece  20  is in abutting engagement with the second boss  82  of the second piece  22  at the corresponding abutment surfaces  94 . Also, the fourth boss  60  of the first piece  20  is in abutting engagement with the first boss  80  of the second piece  22  at the corresponding abutment surfaces  94 . In this configuration the third mount hole  62  of the first piece  20  is aligned and coaxial with the fourth mount hole  86  of the second piece  22 , and the fourth mount hole  64  of the first piece  20  is aligned and coaxial with the third mount hole  84  of the second piece  22 . 
         [0039]    Once the first piece  20  is properly positioned relative to the second piece, the fasteners  92  are installed and tightened to securely fix the first  20  and second  22  pieces together. As the fasteners  92  are tightened, the first  50  and second  52  mount holes of the first piece  20  are brought into alignment with corresponding mount holes (not shown) in the cylinder head  14 . Then fasteners  102  ( FIG. 4A ) are installed through the first  50  and second  52  mount holes to secure the first piece  20  to the cylinder head  14 . 
         [0040]    As such, the first  20  and second  22  pieces are separately mounted to the cylinder head  14  and are also attached to each other. The tube portion  24  of the converter assembly  18  is welded or similarly attached to the first piece  20  prior to the first  20  and second  22  pieces being attached to the cylinder head  14 . When service or maintenance operations are required, the fasteners  92  and  102  are removed and the first piece  20  and the associated converter assembly  18  are easily removed from the cylinder head  14  without having to remove the second piece  22  from the cylinder head  14 . In other words, the converter assembly  18  can be easily removed from the cylinder head  14  without having to have access to the lower fasteners  96 . 
         [0041]    Further, a mechanical advantage is utilized for parallel non-vertical surfaces that drive the first piece  20 , i.e. a converter assembly flange, toward a mount face of the cylinder head  14 . This creates a sufficient amount of force to seal the connection joint to keep exhaust gases from escaping. The relative vertical movement and force is generated during installation of the fasteners  92  that pass through clearance holes, i.e. the third  62  and fourth  64  mount holes of the first piece  20 , and thread into tapped holes, i.e. the third  84  and fourth  86  mount holes of the second piece. As such, the fasteners  92  and  102  are easily accessible from above the converter assembly  18 , which provides improved serviceability. 
         [0042]    Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.