Abstract:
A flow through pressure regulator apparatus and method for directing a flow of fuel and reducing valve seat wear within a fuel system. Present invention includes a lower housing having fuel inlet where fuel flows through the fuel inlet and communicates with a valve assembly and valve biasing member. The valve assembly comprises a lower and upper valve member where the lower valve element contains a plurality of fuel passages. The valve biasing member permits or inhibits fuel flow through the lower valve member by opening and closing an upper valve member. 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 upper valve member through the plurality of fuel passages that encircle the lower valve member 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 TO RELATED APPLICATIONS 
     This application is a continuation in part of U.S. patent application Ser. No. 10/997,654, filed 24 Nov. 2004, now abandoned the entirety of which is incorporated by reference. This application claims priority to U.S. Provisional Patent Application Ser. No. 60/621,246 filed 22 Oct. 2004. 
    
    
     FIELD OF INVENTION 
     This invention relates to pressure control devices in general and more particularly, a pressure control device containing a valve assembly that guides an upper valve member and includes a plurality of fuel passages for directing the flow of fuel used in automotive fuel systems. 
     BACKGROUND 
     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. 
     Pressure regulators known in the art 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. 
     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, there exists a need to develop a fuel pressure regulator that is small in size with fewer parts. There also exits a need to develop a valve assembly that prevents wear of the valve seat due to erratic movement of the upper valve member. 
     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 
     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; the valve assembly comprising a lower valve member wherein a plurality of fuel passages are circumferentially spaced around a top portion of the lower valve member to direct the flow of fuel; the valve assembly regulating the flow of fuel from a fuel inlet through the lower housing to a fuel outlet wherein an upper valve member rests on a valve seat in a closed position to prohibit the flow of fuel from the fuel inlet to the fuel outlet; a valve biasing member for biasing the upper valve member toward the fuel chamber in opposition to pressure exerted on the upper valve member 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. 
     In accordance with another aspect of this invention, a valve assembly for a pressure regulator comprising: an upper valve member; a lower valve member housing the upper valve member wherein a plurality of fuel passages are disposed around the circumference of the an upper portion of the lower valve member to direct the flow of fuel received from a fuel inlet; and the upper valve member resting on a valve seat in a closed position to prohibit the flow of fuel from the fuel inlet to a fuel outlet. 
     In accordance with another aspect of this invention, a method for regulating fuel in a flow through pressure regulator, the method comprising: providing a lower valve member comprising a plurality of fuel passages to direct fuel from a fuel inlet to a fuel outlet; communicating the fuel flow with a valve biasing member after the fuel flows through the lower valve member; and providing an upper valve member to prohibit the fuel flow to the fuel outlet. 
     It is therefore an object of the present invention to provide improved flow characteristics of a fuel pressure regulator free of any additional parts. 
     It is an object of the present invention to improve valve seat wear by guiding the upper valve member as it is lifted off the seat. 
     It is also an object of the present invention to reduce the materials and manufacturing costs of fuel pressure regulators. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  illustrates a perspective view of the valve assembly with a plurality of fuel passages in the lower valve member. 
         FIG. 2  shows cross section view of the valve assembly. 
         FIG. 3  illustrates a cross sectional view of a flow through regulator that includes a valve biasing member. 
         FIG. 4  illustrates is a perspective view of the flow through pressure regulator that includes a valve biasing member. 
         FIG. 5  illustrates a top view of the valve biasing member. 
         FIG. 6  illustrates a perspective view of a fuel cover for the flow through pressure regulator. 
         FIG. 7  is a graph illustrating the relationship between pressure, measured in kilopascals, and flow rate, measured in kilograms per hour. 
         FIG. 8  illustrates a top view of an alternative 3 point of contact embodiment of the valve biasing member. 
         FIG. 9  illustrates a top view of an alternative spiral embodiment of the valve biasing element. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 and 2  illustrate a valve assembly  5  according to the present invention comprising a lower valve member  30  and an upper valve member  80 . The lower valve member  30  includes a fuel chamber  40  which is generally cylindrical in shape and contains a plurality of spaced fuel passages  45  surrounding the top portion of the lower valve member  30 . The plurality of fuel passages  45  will control and direct fuel as it passes valve seat  70 . By changing the depth, width and angle of a side wall of the plurality of fuel passages  45 , pressure may be regulated and configured to allow a constant pressure flow. Others skilled in the art may be able to change the performance of the valve assembly  5  by controlling the above mentioned parameters. 
     In the preferred embodiment, the plurality of fuel passages  45  are u-shaped, however, others skilled in the art may select alternate shapes including oval, rectangular, v, round or slot form. It is preferred to have the number of the plurality of fuel passages  45  greater than or equal to 6. It is also preferred to have the plurality of fuel passages  45  tapered top down such that the width on the top is greater than the width on the bottom. 
     Lower valve member  30  also partially houses the upper valve member  80  and guides upper valve member  80  when being lifted off the valve seat  70  to prevent lateral or erratic movement of the upper valve member  80 . This will lessen the wear of valve seat  70 . 
       FIGS. 3 and 4  illustrate a valve assembly  5  working in a flow through pressure regulator  10 . Flow through pressure regulator  10  includes a lower housing  20  that contains the lower valve member  30 . 
     Fuel chamber  40  channels the fuel into the pressure regulator  10  from the fuel pump (not shown). 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 lower valve member  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 . 
     Referring to  FIGS. 2 and 5 , valve assembly  5  also includes a valve seat  70  which cooperates with upper valve member  80  that is movably disposed between a closed and open position. In the closed position, the upper valve member  80  contacts and seals against the seating surface of the valve seat  70  and prevents fuel flow through the valve seat  70 . The upper valve member  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 upper valve member  80 . The pressurized fuel will then push upper valve member  80  off of valve seat  70  into an open position. The fuel flows through the valve seat  70  and then flows out the plurality of fuel passages  45  which control and direct fuel as it exits the lower valve member  30 . Once the upper valve member  80  lifts off the seat, the lower valve member  30  guides upper valve member  80  preventing lateral and erratic movement of upper valve member  80  which will wear valve seat  70 . This will also prevent the fuel from hugging the upper valve member  80 . In manufacturing the valve seat  70 , the sealing surface is coined to assure smooth sealing between the upper valve member  80  and the valve seat  70 . 
     Once the pressurized fuel is released, the upper valve member  80  is then biased back into the closed position by the valve biasing member  90 . Valve biasing member  90  functions to hold the upper valve member  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. 
     In the preferred embodiment, the upper valve member  80  is shaped as a sphere and maintains a free floating design. The upper valve member  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 upper valve member  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 upper valve member  80  to assist with movement of the upper valve member  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 upper valve member  80  in an axial upward direction and the upper valve member  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 upper valve member  80  to the valve seat  70  thus closing the opening in the valve seat  70 . A upper valve member  80  suitable but not required is a model used in MICRA FTR model sold by Siemens VDO Automotive Corporation. Others skilled in the art may wish to select different shapes for the upper valve member  80  including a truncated sphere or cone. Others skilled in the art may also choose to weld the upper valve member  80  to the valve biasing member  90 . 
     Referring to  FIG. 4 , the geometry of the valve biasing member  90  provides the force to close the upper valve member  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 . 
     The valve biasing member  90  applies a balanced force to the upper valve member  80  that allows the upper valve member  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. 
     Referring to  FIGS. 3 and 5  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 upper valve member  80 . Others skilled in the art may contact the valve biasing member  90  with the upper valve member  80  with less than or more than three reference points. This feature centers the upper valve member  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 upper valve member to valve seat alignment problem with present invention and therefore, a floating upper valve member  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 upper valve member  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 . 
     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. 
     The graph in  FIG. 7  illustrates that as flow rate increases pressure remains constant in the present invention with valve assembly  5 .  FIG. 7  shows pressure measured on the y axis in comparison to flow rate measured on the x axis with their slope being of primary interest. Ideally the slope of the line on the graph would be zero where there is a constant horizontal pressure line at every flow rate. Practically, as shown with the graph the pressure versus flow characteristics do resemble a slope of close to zero. 
       FIGS. 8 and 9  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. 8 , 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. 9 , the geometry of valve biasing member  90  is a flat disk with a spiral shape having center aperture  140 . 
     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.