Abstract:
A fuel delivery system for a vehicle having an engine, comprising: a pump being configured to provide fuel to the engine; a fluid pathway being in fluid communication with an outlet port of said pump at one end; a regulator being disposed in the fluid pathway, the regulator regulating pressure of the fuel when said pump is pumping fuel into the fluid pathway; and a combination valve being disposed in the fluid pathway, the regulator being located between the combination valve and the outlet port of the pump, wherein the combination valve provides a check valve configured to allow fuel flow in a first direction and a system pressure relief valve configured to allow fuel flow in a second direction, the first direction being opposite to the second direction and the first direction being the same direction fuel is pumped in the fluid pathway by the pump.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is related to commonly owned and assigned U.S. patent application Ser. No.______, attorney docket no. DP-309706, entitled: “COMBINATION VALVE FOR FUEL SYSTEM” filed contemporaneously with this application. The contents of which are incorporated herein by reference thereto.  
       TECHNICAL FIELD  
       [0002]     This application relates to fuel systems for vehicles, and in particular, a fuel delivery system for a vehicle.  
       BACKGROUND  
       [0003]     It is known to provide a fuel tank in a vehicle to hold a reservoir of fuel to be used by an engine of the vehicle. It is also known to provide a fuel pump assembly inside the fuel tank to pump fuel from the reservoir to the engine. Typically, the fuel pump includes a one way check valve configured to allow fuel to exit the fuel pump or fuel tank via a fuel line under certain conditions. Generally, a forward flow check valve consists of a checking device, typically a plunger, such as a pintel having a seal, and a seat that when in contact form a leak proof seal. The pintel and seal are forced against the seat with a spring that provides the proper force to maintain pintel and seal to seat contact during no flow and low-pressure forward flow conditions. This force prevents flow from exiting the fuel tank when the vehicle fuel line is removed or when a sufficient amount of pressure is not in the line.  
         [0004]     During a vehicle shut down pressure in the fuel delivery system past or downstream from the check valve of the fuel pump may increase due to heating of the fuel in the line, which may occur due to heat radiated from the engine after it is shut down. In order to provide a release for this pressure in a vehicle shut down situation a release valve can be positioned to provide the pressure release when a threshold value has been reached. The pressure release valve will allow fuel to be released back into the fuel reservoir. However, such a pressure release downstream from the check valve will cause air to be allowed into the fuel circuit due to the releasing of fuel under pressure. Also, as the fuel in the line is cooled over time a vacuum can be created in the fuel circuit downstream from the check valve caused by the reduction in volume of liquid fuel. Moreover, if the vacuum in the fuel circuit is not sufficient to overcome the pressure setting of the check valve (e.g., spring closing force) a loss of fuel or fuel pressure may occur in the circuit after the check valve. Such a loss of fuel or pressure will have to be overcome during a starting sequence when the pump again starts to pump fuel into the circuit. Overcoming this loss of fuel or pressure in the circuit may cause the starting sequence to take longer than a starting sequence wherein there is no loss of fuel or pressure in the circuit.  
         [0005]     In order to ensure that fuel system pressure is maintained below a certain pressure in the fuel rail during a vehicle shut down, a fuel pressure regulator can be modified to have an expensive lapping process to ensure that a desired fuel pressure is maintained in the fuel rail during vehicle shut down. However, the pressure release of the regulator will be at the same value as the regulator is designed to provide during pumping of the fuel in an engine running or starting sequence.  
         [0006]     Accordingly, it is desirable to maintain a desirable fuel pressure in the fuel rail during vehicle shut down without modifying the fuel pressure regulator and limiting the number of valves positioned in the circuit.  
       SUMMARY  
       [0007]     The above discussed and other drawbacks and deficiencies are overcome or alleviated by a fuel delivery system for a vehicle having an engine, comprising: a pump being configured to provide fuel to the engine; a fluid pathway being in fluid communication with an outlet port of said pump at one end; a regulator being disposed in the fluid pathway, the regulator regulating pressure of the fuel when said pump is pumping fuel into the fluid pathway; and a combination valve being disposed in the fluid pathway, the regulator being located between the combination valve and the outlet port of the pump, wherein the combination valve provides a check valve configured to allow fuel flow in a first direction and a pressure relief valve configured to allow fuel flow in a second direction, the first direction being opposite to the second direction and the first direction being the same direction fuel is pumped in the fluid pathway by the pump.  
         [0008]     A method for maintaining fuel pressure in a fuel delivery system of a vehicle having an engine during engine shut down periods, the method comprising: disposing a fuel delivery system within a fuel reservoir of a vehicle, the fuel delivery system, comprising: a pump being configured to provide fuel to the engine; a fluid pathway being in fluid communication with an outlet port of the pump at one end; a regulator being disposed in the fluid pathway, the regulator regulating pressure of the fuel when the pump is pumping fuel into the fluid pathway; and a combination valve being disposed in the fluid pathway, the regulator being located between the combination valve and the outlet port of the pump, wherein the combination valve provides a check valve configured to allow fuel flow in a first direction and a pressure relief valve configured to allow fuel flow in a second direction, the first direction being opposite to the second direction and the first direction being the same direction fuel is pumped in the fluid pathway by the pump; wherein the pressure relief valve is configured to open when fuel in the fluid pathway exceeds a predetermined value when the engine of the vehicle is not running.  
         [0009]     Another exemplary embodiment is a fuel delivery system for a vehicle having an engine, comprising: a pump being configured to provide fuel to the engine; a fluid pathway being in fluid communication with an outlet port of the pump at one end; a regulator being disposed in the fluid pathway, the regulator regulating pressure of the fuel when the pump is pumping fuel into the fluid pathway; and a combination valve being disposed in the fluid pathway, the regulator being located between the combination valve and the outlet port of the pump, wherein the combination valve provides a check valve configured to allow fuel flow in a first direction, a system pressure relief valve configured to allow fuel flow in a second direction, and a pump pressure relief valve configured to allow fuel flow in the first direction, the first direction being opposite to the second direction and the first direction being the same direction fuel is pumped in the fluid pathway by the pump, wherein the pump pressure relief valve is configured to open at a pressure value higher than the pressure required to open the check valve.  
         [0010]     Yet another exemplary embodiment is a fuel delivery system for a vehicle having an engine, comprising: a pump being configured to provide fuel to the engine, the pump having an outlet port; a combination valve being disposed proximate to the outlet port and being in fluid communication with the pump, wherein the combination valve provides a check valve configured to allow fuel flow in a first direction, a pump pressure relief valve configured to allow fuel flow in the first direction, the first direction being the direction fuel is pumped to the engine, wherein the pump pressure relief valve is configured to open at a pressure value higher than the pressure required to open the check valve.  
         [0011]     The above-described and other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description, drawings, and appended claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is a schematic view of a fuel delivery system;  
         [0013]      FIG. 2  is a cross sectional view of a combination valve constructed in accordance with an exemplary embodiment of the present invention;  
         [0014]      FIG. 3  is a schematic view of a fuel delivery system constructed in accordance with an exemplary embodiment of the present invention;  
         [0015]      FIG. 4  is a cross sectional view of another combination valve constructed in accordance with an exemplary embodiment of the present invention; and  
         [0016]      FIG. 5  is a cross sectional view of yet another combination valve constructed in accordance with an exemplary embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS  
       [0017]     Disclosed herein is an apparatus and system that allows for relief of fuel in fuel pumping system when certain pressures are encountered. In accordance with exemplary embodiments of the present invention multiple valves are combined into a single unit or device thereby reducing costs and points of connection for the valves. The apparatus and systems disclosed herein allow for fuel to be relieved under certain pressure situations without adversely affecting the starting sequence of an engine the system supplies fuel to.  
         [0018]     Referring now to  FIG. 1 , a portion of a typical fuel delivery system or modular reservoir assembly  10  is illustrated schematically. The modular reservoir assembly  10  is, as is known in the related arts, positioned within a fuel tank of a vehicle (not shown) for delivering fuel to an engine of a vehicle. The modular reservoir assembly comprises a bucket  12  in which a fuel pump  14 , a filter  16  and a regulator  18  are housed. The bucket is inserted within the fuel tank or fuel reservoir and provides the necessary fluid paths for the fuel pump to be able to draw and pump fuel to the engine. Accordingly, the fuel pump is in fluid communication with fuel in the fuel tank. During an engine starting event and/or engine running event, fuel pump  14  provides fuel to the engine by pumping fuel to the filter, the regulator, and through a cover  20  by passing fuel through a plurality of conduits, in the direction of arrows  22 , which ultimately provides fuel to the engine of the vehicle.  
         [0019]     As is known in the related arts the regulator is provided to regulate the pressure of the pumped fuel in accordance with predetermined tolerances or pressures. Thus, the regulator ensures that the pumped fuel does not exceed a certain pressure.  
         [0020]     In order to provide unhindered flow of fuel in the direction of arrows  22 , a check valve  24  is positioned within fuel pump  14 . Check valve  24  is configured to allow fuel flow and the direction of arrow  22  while preventing flow of fuel in a reverse direction or back into the fuel pump. An example of such a check valve is described in commonly owned and assigned U.S. patent application Ser. No. 09/992,079 filed on Nov. 19, 2001, the contents of which are incorporated herein by reference thereto. As discussed above, it is desirable to provide an overpressure valve to allow for expanding heated fuel to escape from the fuel line back into the fuel reservoir during vehicle shut down. However, since the check valve is typically a valve which allows flow therethrough under a first set of conditions or pressures, while preventing back flow, an additional valve location is required for this feature since the flow of an overpressure valve in the fuel circuit will be in the opposite direction of the check valve. One attempt to provide this feature in the system illustrated in  FIG. 1  is adapt the regulator to control the fuel pressure in the circuit during vehicle shut down. However, such a configuration can require costly processing modifications to be made to the regulator to prevent a loss of pressure in the fuel rail.  
         [0021]     Moreover, the pressure relief of the modified regulator must be related to the pressure setting of the regulator which as discussed herein may not be the same pressure at which the over pressure relief is desired.  
         [0022]     Referring now to  FIG. 2 , and in accordance with an exemplary embodiment of the present invention, a combination fuel system pressure valve and forward check valve  30  is illustrated. Valve  30  provides both a system overpressure relief valve and a check valve without requiring a costly regulator. This valve design is cost efficient through the use of combining the inner housing of the overpressure valve function with the outer member of the fuel line/forward flow check valve function. In addition, and since the two valves are combined into one unit there is only one installation interface while two separate and distinct flow paths are provided, which typically would require at least two installation interfaces.  
         [0023]     Valve  30  includes a valve housing  32  extending axially and is configured to be disposed in or become part of one of the conduits of the modular reservoir assembly illustrated in  FIG. 3 . The valve housing has a body portion  34  that is generally tubular in shape and has a generally circular cross-sectional shape. Of course, other configurations (e.g., square, hexagonal, etc.) are contemplated to be within the scope of the exemplary embodiments of the present invention. The body portion extends axially and has a passageway  36  extending axially therethrough. The valve housing is made of a rigid material such as metal, plastic, or brass. It should also be appreciated that the valve housing is a monolithic structure being integral, unitary, and one-piece.  
         [0024]     Disposed within passageway  36  is a pressure valve  38 . The pressure valve  38  comprises a body portion  40  which is configured to be axially received within passageway  36 . Body portion  40  is configured to have an annular ring or shoulder portion  42  configured to engage a biasing member  44  that is positioned between shoulder  42  and a portion of a valve seat member  46  of body portion  34 . Body portion  40  also comprises a fluid flow path or conduit  48  which will allow fluid to pass therethrough when body portion  40  is moved in the direction of arrow  50  by a pressure force sufficient to overcome the biasing force of biasing member  44 .  
         [0025]     In order to provide the sealing of valve  38  in the position illustrated in  FIG. 2 , an O-ring or sealing member  52  is disposed within a cavity of body portion  40  for engagement or sealing against a portion of valve seat  46 .  
         [0026]     Body portion  40  further comprises an inner passageway  54 , which is configured to receive a forward check valve  56 . The forward check valve comprises a body portion  58  which is configured to be axially received within passageway  54  for movement therein. Body portion  58  is configured to have an annular ring or shoulder portion  60  configured to engage a biasing member  62  that is positioned between shoulder  60  and a portion of a valve seat member  64  of body portion  40 . Body portion  58  also comprises a fluid flow path or conduit  66  which will allow fluid to pass therethrough when body portion  58  is moved in the direction of arrow  68  by a pressure force sufficient to overcome the biasing force of biasing member  62 . In order to provide the sealing of valve  56  in the position illustrated in  FIG. 2 , an O-ring or sealing member  70  is disposed within a cavity of body portion  58  for engagement or sealing against a portion of valve seat  64 .  
         [0027]     An example of body portion  58  is described and shown as the “valve member” of commonly owned and assigned U.S. patent applications Ser. Nos. 09/935,079; 09/972,289; and 09/992,079 filed Aug. 22, 2001, Sept. 20, 2001 and Nov. 19, 2001 respectively. The contents of which are incorporated herein by reference thereto.  
         [0028]     Referring now to  FIG. 3 , and in accordance with exemplary embodiments of the present invention, a schematic illustration of a fuel delivery system  80  is provided. In an exemplary embodiment, combination fuel system pressure valve and forward check valve  30  is employed and the check valve is removed from its location at the fuel pump. As illustrated in  FIG. 3 , combination fuel system pressure valve and forward check valve  30  is positioned physically above regulator  18  and fuel pump  14 . Accordingly, the following advantages are found due to the location of combination fuel system pressure valve and forward check valve  30 .  
         [0029]     As discussed above, an advantage of this embodiment is that valve  30  contains both checking and fuel system overpressure protection features. In addition, the location of this combination valve is above the fuel pressure regulator in a single line forward system. This system architecture eliminates a requirement of the regulator configured to check fuel pressure. This, in turn, allows for a low-cost pressure relief type valve to be used in place of the more costly regulators. For example, regulators in use today that provide fuel pressure checking features typically require expensive lapping operations to produce good surface finishes for sealing system pressure.  
         [0030]     Thus, a regulator in this system can be configured to only regulate fuel pressure during a fuel pumping event. For example, the regulator can be set to relieve at fuel pressures of approximately 400 kPa. Of course, pressure thresholds greater than or less than the aforementioned values are contemplated to be within the scope of the present invention.  
         [0031]     Another advantage of this system is that while the regulator still remains it is effectively removed from the fuel line circuit on vehicle shut-down because the combination valve is physically above the regulator in the fuel circuit and since the combination valve does not set the system regulation pressure, it can be set to relieve well above the system pressure while still providing the desired system integrity. For example, above the 400 kPa relief setting of the regulator, which is specifically tied to the vehicle requirements such as fuel injector thresholds. An exemplary pressure threshold for the check valve is approximately 20 kPa while the pressure threshold for the relief valve is 600 kPa. Of course, pressure thresholds greater than or less than the aforementioned values for opening combination valve  30  are contemplated to be within the scope of the present invention.  
         [0032]     Accordingly, this higher opening pressure of the overpressure valve  38  requires pressure in the fuel rail to achieve a higher level before any fuel is bled off through valve  38 . This, in turn, keeps more fuel in the line between the check valve  56  and the engine fuel rail downstream of the check valve on vehicle shutdown. This eliminates or reduces the vacuum conditions which may occur in systems using the regulator to provide the relief valve feature, which may be exacerbated by the cooling of the fuel after fuel has been bled off via a relief valve set at a lower value because it is tied to the regulator setting. By eliminating these vacuum conditions, the start times and start time variations are reduced.  
         [0033]     Once the pump is turned on during engine crank the check valve opens and the rail pressure returns to a pressure set by the regulator.  
         [0034]     Referring now to  FIG. 4 , an alternative embodiment is illustrated. Here, a combination fuel system pressure valve, forward check valve and pump pressure valve  90  is illustrated. Combination valve  90  is also contemplated for use in the system depicted in  FIG. 3  as well as the same location (physically above the regulator in the fuel system).  
         [0035]     This valve design is similar to valve  30  in that a forward check valve  56  and system pressure valve  38  are provided. However, outer body portion  34  is configured to be received within an inner opening  92  of yet another outer housing  94 , thereby providing a third valve combined into the assembly. Again, the design illustrated is cost efficient through the use of combining the inner housing of the overpressure valve function with the outer member of the fuel line/forward flow check valve function as well as the combination of outer housing  94  and body portion  34  to provide yet another valve  96  for a fluid path, which in this embodiment configured to a pump overpressure release. In this embodiment valve  96  is configured to provide a release at a pressure that is above the pressure required to open forward check valve  
         [0036]     In this embodiment body portion  34  is configured to have an annular ring or shoulder portion  98  configured to engage a biasing member  100  that is positioned between shoulder  98  and a portion of a valve seat member  102  of outer housing  94 . Body portion  34  also comprises a fluid flow path or conduit (not shown) which will allow fluid to pass therethrough when body portion  34  is moved in the direction of arrow  104  by a pressure force sufficient to overcome the biasing force of biasing member  100 , which will be greater than the force required to overcome biasing member  62  of the forward check valve.  
         [0037]     Therefore, and since the three valves are combined into one unit (valve  90 ) there is only one installation interface while three separate valves are provided, which typically would require at least three installation interfaces. Moreover, and as illustrated in  FIG. 3 , the positioning of the valve removes the valve from the fuel pump and places them in the modular reservoir assembly unit.  
         [0038]     The use of combination valve  30  or  90  above the regulator requires only one pre-tested valve assembly to be installed above the fuel pump, rather than the typical installation of components for two or three separate valves. As described above with regard to  FIG. 3 , the location of either combination valve  30  or  90  places the check valve above the regulator. This effectively removes the regulator from the fuel circuit on vehicle shutdown.  
         [0039]     Referring now to  FIG. 5  another alternative embodiment is illustrated. In this embodiment, a combination pump overpressure protection and forward check valve  120  is provided. Here a forward check valve  56  as discussed with regard to the embodiments of  FIGS. 2 and 4  is combined with a pump overpressure valve  96  discussed with regard to  FIG. 4 . The elements of combination pump overpressure protection and forward check valve  120  are similar to those of valve  30  however, the relief direction of valve  96  is opposite to that of valve  38  discussed with regard to  FIG. 2 . As also discussed above valve  96  is configured to provide a release at a pressure that is above the pressure required to open forward check valve  56 . In addition, an exemplary location of combination valve  120  would be the same location as the forward flow check valve illustrated in  FIG. 1 .  
         [0040]     While the invention has been described with reference to one or more exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. It should also be noted that the terms “first”, “second”, and “third” and the like may be used herein to modify elements performing similar and/or analogous functions. These modifiers do not imply a spatial, sequential, or hierarchical order to the modified elements unless specifically stated.