Abstract:
A flow through pressure regulator apparatus and method for directing a flow of fuel within a fuel system. Present invention includes a lower housing having a fuel inlet where fuel flows through the fuel inlet and communicates with a valve biasing member through a fuel chamber and lower valve element with fuel passages. The valve biasing member permits or inhibits fuel flow through a fuel chamber by opening and closing a ceramic valve element. The valve biasing member comprises a flat disk having at least two reticulated concentric rings coupled by at least one bridge. The fuel flows past an open valve element through the lower valve element fuel passages to the valve biasing member. The valve biasing member then diffuses the flow of fuel. A fuel cover directs the flow of fuel from the valve biasing member to the fuel outlet.

Description:
CROSS REFERENCE OF RELATED APPLICATIONS  
       [0001]     This application claims priority to, and incorporates by reference herein in its entirety, pending U.S. Provisional Patent Application Ser. No. 60/632,094 (Attorney Docket No. 2004P20208US), filed 1 Dec. 2004. This application is a continuation in part of U.S. patent application Ser. No. 10/997,654 (Attorney Docket No. 2004P13150US), filed 24 Nov. 2004, the entirety of which is incorporated by reference. 
     
    
     FIELD OF INVENTION  
       [0002]     This invention relates to pressure control devices in general and more particularly, a pressure control device comprising a valve assembly including a ceramic valve element used in automotive fuel systems.  
       BACKGROUND  
       [0003]     Most modern automotive fuel systems use fuel injectors to deliver fuel to the engine cylinders for combustion. The fuel injectors are mounted on a fuel rail to which fuel is supplied by a pump. The pressure at which the fuel is supplied to the fuel rail must be metered to ensure the proper operation of the fuel injector. Metering is carried out using pressure regulators which control the pressure of the fuel in the system at all engine r.p.m. levels.  
         [0004]     Most pressure regulator valves use an upper valve member made of stainless steel or other metallic material and a lower valve member or valve seat fabricated from a stainless steel or other metallic material. When the valve is open, the valve element lifts off the valve seat and may dither, making contact with the valve seat. When the valve closes, the valve element drops onto the valve seat. A high density metallic valve element has the potential to wear the sealing surface of the valve seat, which is also called galling. This wear can be attributed to the valve element impacting the valve seat and galling between the valve element and the valve seat.  
         [0005]     Coining is a preferred method of improving the sealing surface on the valve seat. A metallic ball or the valve element is used to coin the metallic valve seat. With this process it is possible for galling to occur during coining. When the Young&#39;s Modulus of the valve element and the valve seat are similar, both parts can deform at a similar rate during the coining operation. The result may lead to poor leak performance.  
         [0006]     Pressure regulators known in the art also use a valve biasing member biased to a valve seat with a longitudinal flow passage. At low fuel pressures, the valve seat is biased to a closed position to prevent the flow of fuel through the pressure regulator. As fuel pressure builds in the system, the pressure against the valve seat overcomes the biasing force of the valve biasing member, allowing fuel to flow through the valve seat, thereby controlling the fuel pressure in the system.  
         [0007]     While such pressure regulators have been proven satisfactory, they require a substantial number of parts. In an ongoing effort to reduce the material and manufacturing costs of fuel pressure regulators as well as decrease poor leak performance there exists a need to develop a fuel pressure regulator that is small in size with fewer parts.  
         [0008]     Thus, it is believed that there is a need to provide a pressure regulator to overcome the disadvantages of the known pressure regulator.  
       SUMMARY OF INVENTION  
       [0009]     In accordance with one aspect of this invention, a flow through pressure regulator comprising: a lower housing having a fuel inlet wherein a flow of fuel through the fuel inlet communicates with a valve assembly through a fuel chamber; the valve assembly regulating the flow of fuel through the lower housing to a fuel outlet wherein a valve element rests on a valve seat in a closed position to prohibit the flow of fuel from the fuel chamber to the fuel outlet; a valve biasing member for biasing the valve element toward the fuel chamber in opposition to pressure exerted on the valve element by the fuel in the fuel chamber; and a fuel cover for directing the flow of fuel from the valve biasing member to the fuel outlet.  
         [0010]     In accordance with another aspect of this invention, a valve biasing member for a flow through pressure regulator comprising: a flat disk; the flat disk affixed to a lower housing in a fixed relative position; and a flow of fuel in communication with the flat disk for controlling transmitted flow of fuel from a fuel inlet to a fuel outlet.  
         [0011]     In accordance with another aspect of this invention, a method for reducing noise generation in a flow through pressure regulator, the method comprising: providing a passage for a fuel flow from a fuel inlet to a fuel outlet wherein a valve element prohibits the fuel flow through the passage; and communicating the fuel flow with a valve biasing member during flow through the passage.  
         [0012]     It is therefore an object of the present invention to provide improved noise and flow characteristics of a fuel pressure regulator free of any additional parts. It is also an object of the present invention to reduce the materials and manufacturing costs of fuel pressure regulators. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0013]      FIG. 1  illustrates a perspective view of the valve assembly.  
         [0014]      FIG. 2  illustrates is a cross section view of the valve assembly with the upper valve element in the open position.  
         [0015]      FIG. 3  illustrates a cross sectional view of the flow through pressure regulator that includes a valve biasing member.  
         [0016]      FIG. 4  illustrates a perspective view of the flow through pressure regulator that includes a valve biasing member.  
         [0017]      FIG. 5  illustrates a top view of the valve biasing member.  
         [0018]      FIG. 6  illustrates a perspective view of a fuel cover.  
         [0019]      FIG. 7  illustrates a top view of an alternative 3 point of contact embodiment of the valve biasing member.  
         [0020]      FIG. 8  illustrates a top view of an alternative spiral embodiment of the valve biasing  
     
    
     DETAILED DESCRIPTION  
       [0021]      FIGS. 1, 2 , and  3  illustrate a flow through pressure regulator  10  according to the present invention. Flow through pressure regulator  10  includes a lower housing  20  that contains a fuel tube  30 . Fuel tube  30  houses a fuel chamber  40  which is generally cylindrical in shape and which channels the fuel into the pressure regulator  10  from the fuel pump (not shown). In the preferred embodiment, fuel tube  30  is made from stainless steel. Fuel will first pass through a fuel filter  50  into fuel chamber  40 . Fuel filter  50 , generally circular in shape, it is disposed around lower portion of fuel tube  30  and adjacent to an o-ring  60 . O-ring  60  is positioned below the lower housing  20  to seal and prevent any fuel leakages into other components in the system. O-ring  60  is made of an elastomeric material and is generally circular in shape. Others skilled in the art may select not to use an o-ring  60 .  
         [0022]     Flow through pressure regulator  10  also includes a valve seat  70  which cooperates with valve element  80  that is movably disposed between a closed and open position. In the closed position, the valve element  80  contacts and seals against the seating surface of the valve seat  70  and prevents fuel flow through the valve seat  70 . The valve element  80  is biased into the closed position by valve biasing member  90 . Valve biasing member  90  is held in place by lower housing  20  which crimps over the outer edge of valve biasing member  90 . Others skilled in the art may choose to affix the valve biasing member  90  to lower housing  20  with a weld or clip. Pressurized fuel flows through and accumulates in fuel chamber  40  until the pressurized fuel contacts the bottom surface of the valve element  80 . The pressurized fuel will then push valve element  80  off of valve seat  70  into an open position. The fuel flows through the valve seat  70 . In manufacturing the valve seat  70 , the sealing surface is coined to assure smooth sealing between the valve element  80  and the valve seat  70 .  
         [0023]     Once the pressurized fuel is released, the valve element  80  is then biased back into the closed position by the valve biasing member  90 . Valve biasing member  90  functions to hold the valve element  70  of the flow through pressure regulator  10  in a closed position at a predetermined amount of pressure that is related to the pressure desired by the flow through pressure regulator  10  specification.  
         [0024]     In the preferred embodiment, the valve element  80  is shaped as a sphere and maintains a free floating design. The valve element  80  is made of a ceramic consisting of alumina oxide, to prevent galling from occurring during coining and reduce wear on the valve seat. The valve element  80  performs in wear, heat, corrosive environments and maintains dimensional stability of temperatures up to 2000 degrees F. The valve element  80  is not retained by other components of the flow through pressure regulator  10  and therefore does not share a permanent contact with the valve biasing member  90 . The valve element  80  is free to move both axially and radially when displaced from the valve seat  70 . Valve biasing member  90  is positioned on the upper surface of the valve element  80  to assist with movement of the valve element  80  in an axial direction away from the valve seat  70 . When the pressure of the inlet fuel is greater than the force exerted by the valve biasing member  90 , the fuel pushes the valve element  80  in an axial upward direction and the valve element  80  leaves the valve seat  70 . Fuel flows through the flow through pressure regulator  10  until the pressure of the valve biasing member  90  is strong enough to return the valve element  80  to the valve seat  70  thus closing the opening in the valve seat  70 . Others skilled in the art may wish to select different shapes for the valve element  80  including a truncated sphere or cone. Others skilled in the art may also choose to weld the valve element  80  to the valve biasing member  90 .  
         [0025]     Referring to  FIGS. 3, 4  and  5 , the geometry of the valve biasing member  90  provides the force to close the valve element  80  and seal the opening of the valve seat  70 . Valve biasing member  90  also provides the spring rate necessary to regulate the fuel pressure in the system. The geometry of valve biasing member  90  consists of at least two co-axial concentric rings  100  and  110  adhered together by at least one bridge  120 . The preferred shape of the valve biasing member is annular, however, others skilled in the art may select other shapes including oval. From this geometry, balanced slot openings  130  are formed. In the preferred embodiment, the balanced slot openings  130  are arc shaped. Others skilled in the art may select a balanced slot opening  130  to be shaped as a circle, tubular, triangular or angled. Each concentric ring  110  has a beam length used to calculate the spring rate under Hookes law. The effective beam length is defined as the total length of the valve biasing member  90 . The effect of changing the length of the beams, with all other factors remaining constant, will result in changes to performance criteria. At the same time, by decreasing the open area of balanced slot openings  130  where the ratio of surface area to open area is increased, the fluid flowing though the valve biasing element meets more resistance. Therefore, by increasing the effective beam length of the valve biasing member  90  and decreasing the open area of inner balanced slot opening  130 , to a length greater than the radius of its largest ring, the spring rate decreases making the valve biasing member  90  less stiff. The bridge  120  connects first ring  100  with its adjacent neighbor ring  110  in a reticulated network fashion. Bridge  120  increases the effective length of the beams of valve biasing member  90  which achieves desirable spring rates for the flow through pressure regulator  10 .  
         [0026]     The valve biasing member  90  applies a balanced force to the valve element  80  that allows the valve element  80  to lift straight in an upright manner without any bias. The balanced openings  130  serve as a homogenous diffuser to direct the flow of fuel from the opening of the valve seat  70  to various directions. The balanced openings  130  disperse the fuel flow with improved flow characteristics and less noise.  
         [0027]     The center aperture  140  of the valve biasing member  90  preferably centers on the lower housing  20  and on the central axis of valve seat  70 . In the preferred embodiment, the center aperture  140  provides a three-point contact with the valve element  80 . Others skilled in the art may contact the valve biasing member  90  with the valve element  80  with less than or more than three reference points. This feature centers the valve element  80  and achieves low flow linearity of the flow through pressure regulator  10  resulting in regulation at a low flow at the right pressure. There is no valve element to valve seat alignment problem with present invention and therefore, a floating valve element  80  design which typically requires an additional part and that is in common in other regulator designs is not required. Others skilled in the art may allow the valve element  80  to float in a radial direction by reducing the diameter of or eliminating entirely the center aperture  140  of the valve biasing member  90 .  
         [0028]     Referring to  FIGS. 3 and 6 , flow through pressure regulator  10  also includes a fuel cover  150 . The fuel cover  150  is made of a plastic molded material and generally houses the flow through pressure regulator  10 . Fuel cover  150  includes fuel passageway  160  for directing and turning the flow of fuel from the valve biasing member  90  to fuel outlet  170 . The fuel outlet  170  is generally circular in shape and located on the outer edge of cover  150 . Fuel cover  150  also includes at least one snap mechanism  180  allowing ease when being affixed to the flow through pressure regulator  10 . The snap mechanism  180  may be directly molded into the fuel cover  150  as an integral clip. This eliminates the need for separate clip attachments. In the preferred embodiment, the snap mechanism  180  is a tab acting as a clip to hold the flow through pressure regulator  10  in place. One skilled in the art may choose not to affix fuel cover  150  to the flow through pressure regulator  10  and use flow through regulator  10  free of fuel cover  150 . Fuel cover  150  also acts to keep the valve biasing member  90  submerged in fuel at all times during fuel flow which enhances durability of the valve biasing member  90  as well as dampen any vibrating noise of the valve biasing member  90 . After exiting valve biasing member  90 , the fuel builds in the cover chamber  190  above the valve biasing member  90  and climbs over internal wall  200  and then flows to fuel outlet  170 . By this process, the flow of fuel exits in an organized flow and does not discharge in various directions. Similarly, submergence of the valve biasing member  90  in the fuel ensures that the fuel is located on both the top portion and the bottom portion of the valve biasing member  90 . Submergence of the valve biasing member  90  in fuel also ensures that the fuel is not aerated which consequently lessens noise in the flow through pressure regulator  10 . Lastly, the fuel cover  150  protects the valve biasing member  90  during shipping and handling.  
         [0029]      FIGS. 7 and 8  illustrate alternative embodiments of the valve biasing member  90 . In these embodiments, all the various elements of the flow through pressure regulator  10  are identical with exception to the valve biasing member  90 . In  FIG. 7 , the geometry of valve biasing member  90  is a flat disk including at least a three point of contact aperture  140  with no concentric ring geometry. In  FIG. 8 , the geometry of valve biasing member  90  is a flat disk with a spiral shape having center aperture  140 .  
         [0030]     While the present invention has been disclosed with reference to certain embodiments, numerous modifications, alterations, and changes to the described embodiments are possible without departing from the sphere and scope of the present invention. Accordingly, it is intended that the present invention not be limited to the described embodiments and equivalents thereof.