Abstract:
Snap action valve assemblies for use in conduits of automotive exhaust systems have their operation controlled by use of inertia damper elements coupled to an axle of a rotatable valve plate of the valve assembly.

Description:
FIELD 
       [0001]    The present disclosure relates to improving flapper valve motion with an inertial damper. 
       BACKGROUND 
       [0002]    This section provides background information related to the present disclosure which is not necessarily prior art. 
         [0003]    Inertia dampers are known for smoothing the output of rotary stepper motors and the like, but, to date, no such elements have been used with rotary valve elements for automotive exhaust systems, such as snap-action valves with a rotary valve plate and a bias return spring. Such valves can present vibration and noise problems while rotating due to resonance of the valve flap and bias spring. 
       SUMMARY 
       [0004]    This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
         [0005]    In one aspect of the present teachings, in a valve assembly including a valve plate rotatable about an axle and a bias return spring coupled to a first end of the axle, an inertia damping element coupled to a second end of the axle is provided. 
         [0006]    In a second aspect of the invention, a muffler for an internal combustion engine exhaust system includes a housing having an outer shell and input and output headers enclosing opposite ends of the shell. A conduit is positioned within the housing and a valve assembly having a valve flap is positioned inside the conduit for rotation about an axle pivotally coupled to the conduit between a fully closed position wherein a first peripheral portion of the valve flap is in contact with an inner surface of the conduit and a fully open position wherein a plane of the valve flap is substantially parallel to a longitudinal axis of the conduit and a second peripheral portion of the valve flap is in contact with an inner surface of the conduit. An inertia damper element is coupled to an end of the axle. 
         [0007]    Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       DRAWINGS 
         [0008]    The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
           [0009]    The objects and features of the present teachings will become apparent from a reading of a detailed description taken in conjunction with the drawing, in which: 
           [0010]      FIG. 1  presents a plan view of a muffler conduit in which a snap action valve is mounted and equipped with an inertial damper element arranged in accordance with the present teachings; 
           [0011]      FIGS. 2A ,  2 B present respective front and side plan views of an embodiment of a damper disk arranged in accordance with the present teachings; 
           [0012]      FIGS. 3A ,  3 B present respective front and side plan views of a first alternative embodiment of a damper disk having reduced weight; 
           [0013]      FIGS. 4A ,  4 B present respective front and side plan views of a second alternative embodiment of a damper element arranged in accordance with the present teachings; 
           [0014]      FIGS. 5A ,  5 B present respective front and side plan views of a third alternative embodiment of a damper element arranged in accordance with the present teachings; 
           [0015]      FIGS. 6A ,  6 B present respective front and side plan views of a fourth alternative embodiment of a damper element arranged in accordance with the present teachings; 
           [0016]      FIGS. 7A ,  7 B present respective front and side plan views of a fifth embodiment of a damper element arranged in accordance with the present teachings; and 
           [0017]      FIG. 8  is a side cross-sectional view of a muffler housing a snap action valve equipped with an inertia damper element arranged in accordance with the present teachings. 
       
    
    
       [0018]    Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
       DETAILED DESCRIPTION 
       [0019]    Example embodiments will now be described more fully with reference to the accompanying drawings. 
         [0020]    Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. 
         [0021]    The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
         [0022]    When an element or layer is referred to as being “on”, “engaged to”, “connected to” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to”, “directly connected to” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
         [0023]    Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments. 
         [0024]    With reference to  FIG. 1 , muffler conduit  100  houses a snap action valve (whose valve plate is not shown). The valve is equipped with an inertial damper element  102  mounted to one end of valve axle  104  and a bias return spring  106  coupled between an opposite end of axle  104  and a spring mounting post coupled to the conduit  100 . Preferably, damper element  102  is mounted to valve axle  104  by welding. 
         [0025]    In the embodiment of  FIG. 1 , inertial damper assembly  102  is comprised of a plurality of substantially solid disk elements  102 a, b, c and d. Each disk is as shown in  FIGS. 2A and 2B  a substantially solid disk  202  having a central aperture  204  for receipt of axle  104 . Any number of such disks can be utilized in obtaining the precise weight of the damper element desired. 
         [0026]    There are other approaches to adjusting the weight of the inertia damper element, some of which are set forth in the embodiments of  FIGS. 3A , B through  6 A, B. 
         [0027]    In the embodiment of  FIG. 3A , B, damper disk body  302  has its weight adjusted by providing a plurality (in this case four) of through apertures  306   a, b, c  and  d.  These apertures are spaced substantially uniformly about a central aperture  304  for receipt of the valve axle. 
         [0028]      FIGS. 4A , B present a “steering wheel”-type approach to weight adjustment wherein damper element  402  has a rim  410  with spokes  407   a, b, c  and  d  extending inwardly from rim  410  to a central axle mounting hub  409  which has a through opening  404  for receipt of the valve axle. Mounted to and surrounding rim  410  is a weight adding element  408 . 
         [0029]    In the embodiments of  FIGS. 5 and 6 , weighted nodules or lobes are connected to a central axle mounting hub via spoke elements. In the embodiment of  FIGS. 5A , B, four such nodules  506   a, b, c  and  d  of damper element  502  are respectively coupled to central axle mounting hub  509  via spokes  507   a, b, c  and  d.  The valve axle is received through opening  504  in hub  509 . 
         [0030]    In the embodiment of  FIG. 6A , B, only two nodules  606   a  and  606   b  of damper element  602  are utilized, and each are coupled to an axle mounting hub  609  via spokes  607   a  and  607   b.  Through passage  604  in hub  609  receives the valve axle. 
         [0031]    The inertia damper elements described above with reference to  FIGS. 1-6  provide a simple mass welded to the valve axle and they all tend to damp all vibrations present in the valve system. An alternative is a tuned damper set forth in  FIGS. 7A , B. In this arrangement, a tuning coil spring  706  is utilized in conjunction with disk elements to address specific frequencies at resonance of the system. The spring rate and mass of the damping element can be varied in known approaches to minimizing vibrations at resonance. As seen from  FIGS. 7A , B, rather than connecting damper element  702  directly to axle  104 , coil spring  706  has one end embedded in an aperture in damper disk  702  and has its opposite end embedded in valve axle  104 . Spring  706  has most of its body coiled around axle  104 . Disk  702  is provided with a central aperture  704  for receipt of valve axle  104 . Disk  702  is rotatably movable with respect to axle  104 . 
         [0032]      FIG. 8  depicts one exemplary application of a snap action valve with damper element used in a automotive muffler  800 . 
         [0033]    Muffler  800  includes a housing shell  801  closed at either end by an input header  830  and an output header  828 . 
         [0034]    A through conduit  804  is positioned within muffler  800  and in this embodiment extends clear through the muffler body. Conduit  804  includes a first series of perforations  808  and a second plurality of perforations  810 . Inside muffler housing  801  a first internal partition  803  defines chamber  824  with input header  830  and shell  801 . Internal partition  805  defines chamber  822  in conjunction with output header  828  and shell body  801 . Perforations  808  allow communication between exhaust flowing through conduit  804  and chamber  824  which is filled with sound absorbing material  812  such as fiberglass roving. 
         [0035]    Similarly, the second plurality of perforations  810  in conduit  804  provide fluid communication between the exhaust in conduit  804  and chamber  822  which is filled with sound absorbing material  814 . 
         [0036]    Openings  807  in partition  803  permit fluid communication between chambers  824  and  820 , while openings  809  in partition  805  permit fluid communication between chambers  820  and  822 . 
         [0037]    Rotary snap action valve assembly  806  includes a valve plate  850  carrying a vibration absorbing damper pad  826  about a portion of its periphery which would normally be in contact with an interior surface of conduit  804  in a closed position of the valve. At one end of an axle  830  of the valve inertia damper element  802  is mounted, while at an opposite end of the axle  830  a return bias spring  840  is shown. Valve assembly  806  is housed in chamber  820  located between partitions  803  and  805  and this chamber is free from sound absorbing material in this embodiment. When the pressure of the exhaust flowing through conduit  804  reaches a threshold value, the mass of the valve assembly  806  is overcome and the valve plate  850  is swung toward a full open position. This valve motion is smoothed by the braking action of inertia damper element  802 . 
         [0038]    The various embodiments of inertia dampers disclosed add braking mass to the valve to reduce the amplitude of the resonance vibration of the valve flap and bias spring. 
         [0039]    The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention.