Abstract:
A fuel pump having double filter elements that contact the fuel pump module reservoir wall will dampen vibrational energy that originates in the fuel pump and propagates through the filter elements and into the fuel pump module reservoir. The fuel filter apparatus situated within the fuel pump module reservoir has a fuel pump with a fuel filter carrier attached to an end of the fuel pump. The fuel filters that attach to the fuel filter carrier are doubled such that one lies over the other in an over-lapping or sock-like arrangement. The outside filter presses against the wall of the fuel pump module reservoir to dampen any vibration that propagates from the fuel pump. The fuel filters lie under the fuel pump in such a way that they are between the fuel pump and the fuel pump module wall with which they make contact.

Description:
FIELD OF THE INVENTION  
       [0001]     The teachings of the present invention relate to a vibration dampening filter for a fuel pump. More specifically, the teachings of the present invention relate to a double filter for a vertically or horizontally mounted fuel pump.  
       BACKGROUND OF THE INVENTION  
       [0002]     Modern automobile fuel supply systems are generally suitable for their applications; however, each is associated with its share of problems. Most automobiles have a fuel tank in the rear of the vehicle, located just aft of the rear wheels. The fuel tank has a fuel pump module situated within a fuel pump module reservoir. The fuel pump module utilizes an electric fuel pump that generates vibrational sound energy when it is engaged in pumping. The vibrational energy propagates from the fuel pump in various directions before it reaches the ear of a vehicle occupant or a person standing outside of the vehicle.  
         [0003]     In one instance, the vibrational energy travels from the fuel pump, into a rigid fuel filter carrier attached to the fuel pump, through the fuel filter which is supported by the rigid carrier, and into the wall of the fuel pump module reservoir. Since the reservoir is held against the inside bottom surface of the fuel tank, noise propagates into the fuel tank wall and then into other parts of the vehicle that contact the tank and also into the area surrounding the vehicle. In both instances, the noise may be at such a level to be heard by a person.  
         [0004]     In another instance, the vibrational energy travels from the fuel pump, and into the liquid fuel within the fuel pump module reservoir. The noise propagating through the liquid fuel then propagates into the wall of the fuel pump module reservoir at various locations of the fuel pump module reservoir. Since the reservoir is held against the inside bottom surface of the fuel tank, noise reflecting off of the fuel pump module reservoir walls will travel through the reservoir walls and propagate into the fuel tank wall and then into other parts of the vehicle that contact the fuel tank and also into the areas surrounding the vehicle. In both instances, the noise may be at such a level to be heard by a person.  
         [0005]     A need exists then for a fuel pump module that does not suffer from the above limitations. This in turn, will result in a vibration dampening double filter for a fuel pump that dampens vibrational sound energy encountering or passing through the fuel filter from any direction and that reduces or eliminates vibrational sound energy that otherwise may be heard by vehicle occupants or bystanders.  
       SUMMARY OF THE INVENTION  
       [0006]     A fuel pump module has a reservoir and a fuel pump located within the reservoir. The fuel pump has a double filter, that is, a first filter element that is wrapped around a rigid carrier and a second filter that is wrapped around the first filter element. The carrier is connected to an end of the fuel pump. The outside filter contacts the fuel pump module reservoir wall and dampens vibrational sound energy that originates in the fuel pump and propagates through the carrier and into the fuel pump module reservoir walls. The double filter also absorbs vibrational sound energy that propagates through the liquid fuel and into the fuel pump module reservoir wall via the fuel filters. The fuel filters that attach to the fuel filter carrier are doubled such that one lies over the other in an over-lapping or sock-like arrangement. The outside filter presses against the fuel pump module reservoir wall and dampens any vibrational energy that propagates from the fuel pump. The fuel pump and the outside filter may or may not define a gap. The fuel filters lie under the fuel pump in such a way that they are between the fuel pump and the fuel pump module reservoir wall with which they make contact.  
         [0007]     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0009]      FIG. 1  is a side view of a vehicle depicting its fuel system in phantom;  
         [0010]      FIG. 2  is a perspective view of a fuel pump module and reservoir according to teachings of the present invention;  
         [0011]      FIG. 3  is a side view of a fuel tank and fuel pump module depicting a vertical fuel pump and accompanying filters in phantom according to teachings of the present invention;  
         [0012]      FIG. 4  is a side view of a fuel tank and fuel pump module depicting a horizontal fuel pump and accompanying filters in phantom;  
         [0013]      FIG. 5  is side view of a circular double filter before welding the filter elements in their final position according to the teachings of the present invention;  
         [0014]      FIG. 6  is a top view of the circular double filter before welding the filter elements in their final position according to the teachings of the present invention;  
         [0015]      FIG. 7  is a bottom view of the circular double filter before welding the filter elements in their final position according to the teachings of the present invention;  
         [0016]      FIG. 8  is a top view of the circular double filter after welding the filter elements according to the teachings of the present invention;  
         [0017]      FIG. 9  is a side view of an elongated double filter depicting both filter elements after welding according to the teachings of the present invention;  
         [0018]      FIG. 10  is a side view of the elongated double filter depicting the first, inner filter element before placement and welding of the outer filter element according to the teachings of the present invention;  
         [0019]      FIG. 11  is a side assembly view of the elongated double filter depicting how the outer filter installs over the inner filter; and  
         [0020]      FIG. 12  is a top view of the elongated double filter depicting both filter elements after welding according to the teachings of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0021]     The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. Turning now to the teachings of the present invention,  FIGS. 3 through 12  depict a vibration dampening double filter for a fuel pump. Because such a double filter resides within a reservoir  20  of a fuel pump module  18 , an explanation of the filters&#39; surroundings will be presented.  FIG. 1  depicts an automobile  10  that houses a fuel pump module  18  within a fuel tank  14  located in the rear of the vehicle  10 . A fuel pump of the fuel pump module  18  pumps fuel from the fuel tank  14  through a fuel line  16  to the front of the vehicle  10  to an engine  12 .  
         [0022]      FIG. 2  depicts a fuel pump module  18  having a fuel pump module reservoir  20  and a fuel pump module flange  33 . The flange  33  holds a fuel outlet  30  and a fuel inlet  32  of the fuel pump module  18 . Additionally, the flange  33  secures a first strut  22  having a first strut spring  24 , and a second strut  26  having a second strut spring  28 . The first strut spring  24  and second strut spring  28  bias the reservoir  20  against the bottom of the fuel tank  14 , as depicted in  FIGS. 3 and 4 .  
         [0023]      FIGS. 3 and 4  depict alternate arrangements of the vibration dampening double filter for a fuel pump according to the teachings of the present invention.  FIG. 3  depicts a vertically arranged fuel pump  34  while  FIG. 4  depicts a horizontally arranged fuel pump  82 . Turning to  FIG. 3 , and  FIGS. 5 through 8 , a more detailed explanation of the vertical fuel pump  34  having a vibration dampening double filter will be explained. The vertical fuel pump  34  depicts a rigid filter carrier  48 , an inner filter  38 , and an outer filter  40 . As depicted in  FIG. 3 , the outer filter  40  contacts the bottom inside surface of the fuel pump module reservoir  20 . The bottom outside surface of the fuel pump module reservoir  20  contacts the bottom inside surface of the fuel tank  14 . This is one arrangement through which vibration sound dampening is able to take place.  
         [0024]     With continued reference to  FIG. 3 , and  FIGS. 5 through 8 , the fuel pump  34  is press-mounted into fuel pump mount  44  and surrounded by the fuel filter guides  42 , which are part of the filter carrier  48  as depicted in  FIG. 5 . The fuel filter guides  42  and the carrier  48 , although a single structural piece, are also linked by a fuel pump inlet  46  defined through the carrier  48 . The carrier  48  secures the inner fuel filter  38  and the outer fuel filter  40  below and adjacent the fuel filter  34 . As depicted in  FIGS. 6 and 7 , the inner fuel filter  38  and outer fuel filter  40  are each a single piece of gradient density (GD) filter material. The hour-glass or double-circular or near double-circular shape of the material depicted in  FIG. 6  is folded to create the overall thickness of four gradient density layers. Each gradient density layer of filter material is itself a multi-layer structure. Each sub-layer of the inner filter  38 , for example, is capable of filtering a different size of particulate matter from fuel passing through the filter  38 . A multitude of different filter materials having various filter qualities are possible, that is, the size of the pores in the filter material can vary between layers to provide the desired filter characteristics.  
         [0025]     Continuing with the vertical fuel filter  34 , when the inner fuel filter  38  and outer fuel filter  40  are folded over, they are welded about the periphery of the newly formed circular or near circular shape, as depicted in  FIG. 8 .  FIG. 6  depicts the filter structure in its as-cut geometry, prior to folding and welding. The weldable area  58  is also shown, as depicted in  FIGS. 6 and 7 .  
         [0026]      FIG. 6  is a top view depicting the carrier with its fuel pump mount  44 , its fuel pump inlet  46 , and fuel pump alignment hole  50 . The fuel pump  34  has a projection (not shown) that press fits into the fuel pump mount  44 . The fuel filter guide  42  helps guide the fuel pump  34  during installation and helps to secure the fuel pump  34  after its press-fitting into the fuel pump mount  44 . When the fuel pump  34  is properly installed in the carrier  48 , an alignment peg (not shown) of the fuel pump  34  becomes lodged within the fuel pump alignment hole  50 . Additionally, a fuel regulator alignment hole  56  resident in a fuel regulator holder  57  secures a fuel regulator (not shown) located adjacent to the fuel pump  34 . The fuel regulator holder  57  is an integral part of the carrier  48 .  
         [0027]      FIG. 7  is a bottom view of the circular double filter  38 ,  40  before welding the filter elements  38 ,  40  together.  FIG. 7  depicts the carrier  48  that defines the fuel pump inlet  46 . Additionally, the arm and leg structure of the carrier  48  is depicted, which permits the carrier  48  to provide a space between the folded layers of the inner fuel filter  38 . This space helps facilitate the flow of fuel from the reservoir  20 , through the filters  38 ,  40  and into the fuel pump inlet  46  so that the fuel pump  34  can be continuously supplied with fuel.  FIG. 7  depicts the fuel pump inlet  46  located within the arm and leg arrangement of the carrier  48 . The positioning of the fuel pump inlet is in the space or gap created by the arms and legs when the filters  38 ,  40  are welded. Also depicted in  FIGS. 6 and 7  is the weldable area  58 , which becomes the welded area  52  upon welding the inner fuel filter  38  and outer fuel filter  40  as depicted in  FIG. 8 , which will now be discussed.  
         [0028]      FIG. 8  depicts a top view of the near circular double filter  38 ,  40  after welding the filter elements  38 ,  40  according to the teachings of the present invention. To arrive at the completed filter depicted in  FIG. 8 , a portion of the filter structure  38 ,  40  of  FIG. 6  is folded under the fuel regulator holder  57  as depicted in  FIG. 5  by the directional arrow. The filter elements  38 ,  40  are folded about a fold  54  to create the clam-like structure. The welding of the filter elements  38 ,  40  about weldable area  58  is accomplished by subjecting the weldable area  58  to heat with an iron or between platens, for example, or another suitable heating element.  
         [0029]     In another embodiment according to the teachings of the present invention, a horizontal filter and fuel pump arrangement  80  is depicted in  FIG. 9 . A horizontal fuel pump  82  lies parallel to an inner fuel filter  90  and an outer fuel filter  92 , which lie below the fuel pump  82 , when it is installed in the fuel reservoir  20 . The inner fuel filter  90  and outer fuel filter  92  are welded together as indicated by the weld area  94 . The horizontal fuel pump  82  is attached to a fuel pump mount  84  that has a fuel inlet tube  88 . The fuel pump mount  84  has the same fuel pump mount  44 , alignment hole  50 , and fuel pump inlet  46  as that depicted in  FIG. 8 . The fuel inlet tube  88  draws fuel from the filter carrier  96 , which is surrounded by the fuel filters  90 ,  92  and delivers the fuel through the fuel pump mount  84 , out of the fuel outlet port  100  ( FIG. 12 ), and into the fuel pump  82 . The fuel pump  82  then pumps the drawn fuel into the fuel outlet line  86  so that fuel is delivered through the fuel outlet  30  adjacent the flange  33  and into the fuel line  16  to the engine  12 .  
         [0030]     Continuing with reference to  FIGS. 9 through 12 , the inner fuel filter  90  is placed over the filter carrier  96 , which is an elongated piece of rigid material, such as plastic. The outer filter  92  slides over the inner filter  90  as depicted in  FIG. 11  to form a double filter over the carrier  96 . Upon positioning of the sock-like outer filter  92 , the outer filter  92  and inner filter  90  are welded together about the periphery  104  of the double filter arrangement. The outer filter  92  has a top outer filter edge  98  that lies just in front of and adjacent to the fuel pump mount  84 . The outer filter  92  also has a bottom outer filter edge  102 . These areas are not welded after the sock-like outer filter  92  is slid over the inner filter  90  and into position.  
         [0031]     Now, an explanation of vibrational sound dampening, as it relates to the teachings of the present invention, will be provided. Although appropriate fuel filtering and some vibrational dampening results from the use of a single gradient density (GD) filter material, uses a double filter  38 , 40  provides a dual filter and increased dampening of audible vibrational energy that emanates from the fuel pump  34 ,  82 . For instance, in the vertical fuel pump arrangement of  FIG. 3 , the inner filter  38  and outer filter  40  each provide a layer of filter material that dampens audible vibrational energy that emanates from the fuel filter  34 . In a first example, audible vibrational energy emanates from the fuel pump  34 , through the rigid filter carrier  48 , through the filters  38 ,  40  through the wall of the reservoir  20 , through the fuel tank  14 , and into the surrounding atmosphere where it may be heard by a person.  
         [0032]     Additionally, because the gradient filter material is of a double thickness, the same gradient of audible vibrational dampening is experienced twice when audible vibrations are subjected to the filter, as opposed to a single gradient filter, even one of a thickness equal in thickness to a double thickness. The result of such a structure is that the audible frequencies are subjected to the same gradient density filter material twice, and not just once. This double subjection permits a double trial at dampening the same frequency. This is different than simple providing a thicker material of a continuous gradient design where audible vibrations would only be subjected once to a particular filter gradient material.  
         [0033]     In another example, the fuel filter  34  emanates noise that travels through liquid fuel within the reservoir  20 , reflects back from the walls of the reservoir  20 , through the filters  38 ,  40 , through the wall of the reservoir  20 , and through the fuel tank  14  to the atmosphere where it may be heard by a person. In this scenario, only a portion of the vibrational energy will be reflected back from the reservoir walls, while the balance will pass directly through the wall of the reservoir  20 .  
         [0034]     The horizontal fuel pump arrangement of  FIGS. 4 and 9 - 12  is advantageous in that the longitudinal length of the fuel pump  82  lies adjacent the dual filters  90 ,  92 . Although a gap is defined between the fuel filter  82  and the outer filter  92 , the fuel filter  82  could lie against the outer filter  92 . The gap provides an additional interface of liquid fuel through which any vibrational energy must travel through before reaching the outer filter  92 .  
         [0035]     In the above description, the double filter arrangement has been described and shown such that the filters  40 ,  92  contact the bottom surface of the reservoir  20 . It is easily conceivable that the filters  40 ,  92  in their corresponding vertical and horizontal arrangement, will not contact the wall of the reservoir  20 . In such an application, the filters could be suspended above the wall of the reservoir  20 . In such an arrangement, an additional interface of liquid fuel would exist between the filters  40 ,  92  and the reservoir wall  20 , thus further impeding the propagation of audible vibrational energy to the atmosphere outside of the fuel tank  14 .  
         [0036]     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.