Abstract:
An integrated fuel filter and fuel pump assembly with a water separation capability includes a fuel filter housing and a fuel filter element placed within the fuel filter housing. The fuel filter housing includes an outer surface with a connection interface for a fuel pump. This connection interface includes a fuel inlet port and mounting provisions for threaded fasteners. The fuel pump which completes the integrated assembly includes a fuel inlet and a fuel exit which is directly connected to the flow inlet of the housing. Further, the fuel pump is directly mounted to the outer surface of the housing in a unitized-type of arrangement. The upper endplate for the filter element is enlarged so as to extend beyond the outer diameter of the filter element and additional serve as a closing lid for the housing. A standpipe is mounted into the base of the housing and a knob, which is threadedly received by the upper end of the standpipe, provides the clamping mechanism for pressing the upper endplate tight against the upper end of the housing in order to complete the sealed interface.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates in general to the design and construction of a fuel filter and the integration of a fuel pump with the fuel filter. More specifically the present invention relates to the enhancement of a fuel filter design by adding user-friendly features and beneficial performance features. The integration of the fuel pump is configured so as to maximize the versatility of the compatible pump and filter combinations. 
     Some of the benefits of integrating the fuel filter and fuel pump into a single assembly is to reduce the number of interfacing components, reduce the number of connections, and reduce the overall space requirements. When the fuel filter and fuel pump are separately packaged and assembled into the engine, each component requires its own mounting provisions and connection ports and fittings and its own interconnecting conduits. The space requirements within the vehicle engine to separately position and mount the two components are greater than when the fuel pump is directly integrated into combination with the fuel filter housing. When these two separate components are installed as separate items, more time is required in order to perform the mounting steps and the interconnecting steps for the various flow lines and conduits. 
     The concept of “integration” as used herein refers to the unitizing of the fuel pump into or onto the fuel filter housing. This is achieved by configuring the unitary casting used for the filter housing with suitable mounting provisions for the fuel pump. In addition to the inclusion of mounting provisions for the fuel pump as part of the filter housing, the fluid connection between the pump and the filter housing is direct (i.e., contiguous). As a result of this direct connection, there is no need to provide or use any additional fluid conduits in order to separately connect the fuel outlet of the fuel pump to the fuel inlet of the filter housing. As indicated, this direct connection eliminates the need for separate interfacing conduits and reduces the overall space requirements. 
     The integration of the fuel pump with the fuel filter can be accomplished in one of two primary ways. Considering the filter housing as a unitary casting, the fuel pump can be positioned within the housing by enlarging the housing to accommodate both the fuel filter and the fuel pump. This approach is disclosed by U.S. Pat. No. 5,958,237, which issued Sep. 28, 1999 to Cort, et al. The other primary way of integration corresponds to the present invention wherein the fuel pump is mounted directly to the outer surface of the fuel filter housing so as to create a unitized, integrated, single assembly. 
     One of the advantages of the integration approach of the present invention is the afforded versatility for the selected fuel pump. When the fuel pump is directly mounted to the exterior of the fuel filter housing, the size, shape, and style of pump can be changed without affecting the filter or the housing so long as the mounting interface and the fuel inlet/outlet connection remain compatible. 
     The exterior mounting also enables a quick and efficient exchange or replacement of the fuel pump without having to open the housing. As a result, different pumps with different capacities or flow rates can be used interchangeably with the same fuel filter so long as the mounting interface for the pump remains compatible with the mounting provisions of the housing and so long as the fuel inlet/fuel outlet connection remains compatible. The integration approach of the present invention also enables the use of a smaller casting for the fuel filter housing and thus there is less material and accordingly less expense as compared to the integration approach of U.S. Pat. No. 5,958,237. 
     In addition to the described integration approach of the present invention involving the fuel pump and the fuel filter, there are other improvements provided. The method of integrating the fuel filter lid with the filter element is one such improvement. According to the present invention, the fuel filter endplate which is integrally bonded to the filter element also functions as the closing lid for the fuel filter housing (casting). In this manner, there is an added simplicity to the design of the present invention. Further, a separate lid does not have to be provided and handled. The endplate/lid design utilizes a knob for easy removal of the “lid” and thus removal of the filter element without the need for any hand tool or special implement. Another improvement of the present invention includes the addition of an air bleed hole in order to reduce the amount of fuel vapor trapped inside of the closed fuel filter housing. Vapor trapped upon closing of the housing or generated during operation is able to bleed into a fuel return line, thereby preventing this vapor from reaching the combustion area of the engine. 
     The design features included as part of the present invention provide improvements to the design of the fuel filter and the integration of the fuel pump with the fuel filter and its corresponding housing. These design features are novel and unobvious advances in the art. 
     SUMMARY OF THE INVENTION 
     An integrated fuel filter and fuel pump assembly according to one embodiment of the present invention comprises a fuel filter including a fuel filter housing and a fuel filter element positioned within the fuel filter housing. The fuel filter housing has an outer surface with a connection interface defining a flow inlet and including a fuel pump mounting arrangement. The integrated assembly further includes a fuel pump which has a fuel inlet and a fuel exit and the fuel pump is constructed and arranged for connection with the fuel pump mounting arrangement whereby the fuel pump fuel exit is placed in flow connection with the flow inlet of the housing for delivery of fuel to the fuel filter. 
     One object of the present invention is to provide an improved fuel filter and fuel pump integrated assembly. 
     Related objects and advantages of the present invention will be apparent from the following description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of an integrated fuel filter and fuel pump assembly according to a typical embodiment of the present invention. 
     FIG. 2 is a perspective view of a fuel filter housing comprising one component of the FIG. 1 assembly according to the present invention. 
     FIG. 3 is a perspective view, from a different direction, of the FIG. 2 fuel filter housing. 
     FIG. 4 is a front elevational view, in full section, of the FIG. 2 fuel filter housing as viewed along geometric cutting plane  4 — 4 . 
     FIG. 5 is a side elevational view, in full section, of the FIG. 2 fuel filter housing as viewed along geometric cutting plane  5 — 5 . 
     FIG. 6 is a perspective view of a fuel pump which comprises one component of the FIG. 1 assembly. 
     FIG. 7 is a front elevational view of a standpipe which is assembled into the FIG. 2 fuel filter housing and comprises one component of the FIG. 1 assembly according to the present invention. 
     FIG. 8 is a side elevational view, in full section, of the FIG. 7 standpipe. 
     FIG. 9 is a partial perspective view, in full section, of one portion of the FIG. 1 assembly showing two primary seals and the corresponding sealed interfaces according to the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. 
     Referring to FIG. 1, there is illustrated an integrated assembly  20  of a fuel filter  21  and a fuel pump  22 . The fuel pump  22  is attached directly to the fuel filter housing  23 . Included as part of the fuel filter  21  is a heater/connector  24 , a water-in-fuel sensor  25 , a temperature sensor  26 , and a water drain valve  27 . The operation and functioning of these components is described in U.S. Pat. No. 5,855,772 which issued Jan. 15, 1999 to Miller, et al. and which patent is expressly incorporated by reference herein for its disclosure of these four components. 
     The interior cavity defined by the walls of the filter housing  23  is closed in part by endplate  31  which doubles as a closing lid when used in cooperation with knob  32 . The endplate  31  is attached to the upper end of the filter element so as to function as a normal or traditional endplate in order to close this end of the filter from any potential fluid bypass. While the endplate  31  functions in this traditional fashion, this endplate also has an outwardly-radiating flange portion  28  with an outside diameter size which is noticeably larger than the outside diameter of the generically-cylindrical filter element (see FIG.  9 ), allowing the endplate  31  to also serve as a closing lid for the defined (upper) opening  33  (see FIG. 2) in the filter housing  23 . The endplate  31  includes a filter-facing surface  29  and opposite thereto a knob-facing surface  30 . The knob  32  is internally threaded so as to threadedly assemble onto the (upper) end of a permanent standpipe (see FIGS.  7  and  8 ). 
     Cast (or molded) as part of the filter housing  23  is a mounting bracket  34  which is used to position and secure the integrated assembly  20  in the desired location within the vehicle engine. Two clearance holes  35  and  36  are provided in order to facilitate the attachment of the mounting bracket to some selected support structure or portion of the vehicle engine by the use of threaded fasteners. Depending on the engine size and style, the mounting bracket  34  can take on whatever configuration is most appropriate as to its overall size and geometry. Likewise, the size and spacing of the mounting holes as well as the corresponding hole pattern for the two (or more) clearance holes  35  and  36  can be configured to be compatible with whatever configuration is dictated by the engine. 
     Referring to FIGS. 2,  3 ,  4 , and  5 , the details of filter housing  23  are illustrated. The perspective view of FIGS. 2 and 3 show virtually all of the exterior features including the mounting provisions or arrangement for the fuel pump. The full section views of FIGS. 4 and 5 show the internal features and construction of the filter housing  23  including the mounting portion  39  for the standpipe. Further illustrated as part of the FIGS. 4 and 5 section views is an air bleed hole  40  which connects to the return fuel passageway  41 . 
     Referring first to FIG. 2, there are four, component-mounting portions included as part of the casting which provides filter housing  23 . Portion  43  includes two internally threaded ports  44  and  45 , either one of which may be used for the water-in-fuel sensor  25 . The upper or axially higher port  44  would allow more water to accumulate before draining. The lower port  45  allows less water to accumulate before the sensor  25  is activated, thereby indicating that it is time to open the water drain valve  27 . The water drain valve  27  can be operated manually or automatically by being tied into the electronics for the water-in-fuel sensor. Automatic draining with a manual back-up as well as an override provision provides the preferred coverage. The port which is not selected for receipt of the water-in-fuel sensor is simply plugged and thus becomes inactive in the operation of the integrated assembly  20 . 
     Portion  46  is constructed and arranged for the assembly and receipt of the temperature sensor  26 . Portion  46  is an internally-threaded port which includes a generally cylindrical and raised boss  47 . Portion  48  is constructed and arranged for receipt of the water drain valve  27  and includes two oblong (in lateral cross section) bosses  49  and  50  which are interconnected along a common edge. Portion  53  is constructed and arranged for receipt of heater/connector  24 . The oblong shape (in lateral cross section) includes two internally-threaded holes  54  and  55 . Further, only hole  56  extends completely through the wall of the filter housing so as to enable communication between the heater/connector  24  and the hollow interior of the filter housing  23  as defined by the sidewall  57  and base  58 . 
     Positioned between the hollow interior  61  of the filter housing  23  and the mounting bracket  34  is the return fuel passageway  41 . This integral passageway has an internally-threaded aperture at each end for connection to a fuel line conduit at each end. Whatever fuel is being returned from the injectors or other combustion portion of the engine is designed to flow into one end of passageway  41  and out the other end which is connected to the fuel tank. This particular routing of the returning fuel enables air vapor within the closed filter housing  23  to be routed to the returning flow of fuel by way of the air bleed hole  40 . Hole  40  is open to the hollow interior  61  of the filter housing  23  and is in flow connection with passageway  41  so that any trapped air vapor and any vapor which is generated during operation of the engine and use of assembly  20  is able to escape with the returning fuel (see FIG.  5 ). 
     With reference to FIG. 3, the mounting provisions for the fuel pump  22  (see FIG. 6) are illustrated. Also illustrated is the other (opposite) end  62  of the return fuel passageway  41 . The mounting provisions for the fuel pump  22  include a first or upper boss  63  with a through-hole  64  and two internally-threaded holes  65  and  66 . Additionally, the mounting provisions include a second or lower boss  67  with two internally-threaded holes  68  and  69 . It is intended that whatever fuel pump is selected, noting that various fuel pumps can be used, it will include a mounting flange  22   a  with clearance holes  22   b  and  22   c  of a compatible size and spacing with holes  65  and  66 . Additionally, the selected fuel pump  22  shall include a second mounting flange  22   d,  with two clearance holes  22   e  being illustrated, the flange to be aligned with the second boss  67  such that the two clearance holes  22   e  line up with holes  68  and  69 . As would be understood, threaded fasteners (four total) are used to attach the two mounting flanges  22   a  and  22   d  to the two bosses  63  and  67 . A fuel delivery port  22   f  which is part of the fuel pump is positioned between the two clearances holes in the first mounting flange and inserts into the through hole  64 . An annular, axial compression seal is used to create a liquid-tight interface so that fuel is delivered from the integrated fuel pump into the filter housing without fuel loss due to leakage. Tightening of the mounting hardware creates the requisite clamping (compression force) for the seal. A representative fuel pump  22  is illustrated in FIG.  6 . 
     With further reference to FIGS. 4 and 5, additional construction details for the filter housing  23  are illustrated. For the most part the construction details are self-explanatory based upon the descriptions already provided, the use of the same reference numerals for the same portions, and an understanding of the particular geometric cutting planes. One feature, only briefly mentioned earlier, is the use of standpipe  73  which is securely and effectively permanently assembled into the base  58  of housing  23 . In order to effect this standpipe assembly into the base of the housing, an internally-threaded socket  72  is included as part of the filter housing as is illustrated in FIGS. 4 and 5. The corresponding standpipe  73  is illustrated in FIGS. 7 and 8. When the fuel filter  21  is installed in the filter housing  23 , a lower edge of the fuel filter is adjacent the connection location between the standpipe  73  and base  58 . The upper, opposite end  79  of the standpipe  73  extends beyond the upper, opposite end of the fuel filter and beyond endplate  31  (see FIG.  9 ). 
     Socket  72  includes two internally-threaded portions  72   a  and  72   b.  Portion  72   a  is constructed and arranged to receive the externally-threaded end  74  of standpipe  73 . Standpipe  73  is hollow between flow passage  75  and end  74 , and this conduit  76  provides for the exiting flow of fuel after being filtered. Fuel that enters the hollow center of the filter element is directed into flow hole  75  and from there, down through conduit  76  to portion  72   b.  Accordingly, portion  72   b  provides the fuel outlet port and is internally-threaded for connection to a fuel line for delivery of the fuel to the injectors. 
     The upper end  79  of the standpipe  73  is externally threaded for connection to the closing knob  32 . As will be understood, the standpipe  73  has a length which is sufficient for end  74  to be threaded into portion  72   a  and end  79  to extend upwardly through endplate  31  such that end  79  is exposed and thereby used for assembly of knob  32 . The threaded, manual assembly of knob  32  onto end  79  pushes down on the upper surface  30  of endplate  31  by the underside surface  80  of knob  32 . As this pushing force is exerted by the action of the threaded engagement of knob  32  onto end  79 , the endplate  31  compresses an annular, outer axial compression seal  81  which is positioned around defined opening  33  as illustrated in FIG.  9 . An inner, annular axial compression seal  82  is also axially compressed by the action of knob  32  being manually threaded onto end  79  of standpipe  73  in order to create a liquid-tight interface between the knob and the endplate. 
     The knob  32  is designed with an oversized head  32   a  which is contoured with a slightly concave portion  32   b  on each “side” separated by a slightly convex portion  32   c  at each “corner”. This particular geometry for knob  32  provides an easy grip design for facilitating the manual tightening of knob  32  onto the cooperating standpipe  73  and for removal of the knob from the standpipe. The size of head  32   a  is also beneficial in order to facilitate the manual turning of knob  32  because with a larger radius, the turning force required to create the desired compressive torque is less than what would be needed with a smaller radius or smaller size of knob  32 . Additionally, no tools are need in order to assemble the knob  32  onto or to remove the knob from the standpipe  73 . This permits assembly and removal of the fuel filter relative to the housing, all by hand. 
     The axial compression of the inner annular seal  82  by knob  32  provides a first sealed interface between the interior of fuel filter  21  and the exterior of the fuel filter. This first sealed interface is located between the knob  32  and the upper endplate  31  and is effective to prevent liquid leakage from the interior of the filter past knob  32 . The axial compression of the outer annular seal  81  by endplate  31  by means of knob  32  provides a second sealed interface between the hollow interior  61  of the filter housing  23  and the exterior of the filter housing. The second sealed interface is located between the endplate and the housing and is effective to prevent liquid leakage from the clearance space  61   a  past the endplate and the upper edge of the outer housing wall. 
     The stiffness and rigidity of endplate  31  is sufficient to transmit the force from the tightened knob  32  as it presses against the center area of the endplate from the center area to the outer edge area  31   a  of the endplate  31 . Accordingly, the manual tightening of the knob  32  onto standpipe  73  generates a downward compressive force on the endplate which is effective to axially compress inner seal  82  as well as outer seal  81 . The compression of these two seals creates the previously described first sealed interface and the previously described second sealed interface. 
     In order to capture the inner seal  82  and hold it in the desired location, the endplate  31  is formed with a first U-shaped, annular receiving channel  87  which opens upwardly in the direction of knob  32 . The inner seal  82  which is fabricated out of an elastomeric material has a substantially rectangular shape in lateral section so as to fit snugly into the receiving channel  87 . In order to capture the outer seal  81  and hold it in the desired location, the endplate  31  is formed with a second U-shaped, annular, receiving channel  88  which opens downwardly in the direction of filter housing  23 . The outer seal  81  which is also fabricated out of an elastomeric material has a substantially rectangular shape in lateral section so as to fit snugly into the receiving channel  88 . The axial height or thickness of each seal  81  and  82  relative to the axial height or depth of the cooperating channel is such that a portion of the seal extends beyond the edge of the channel so that there is a protruding portion of the seal material for contact and compression before the clamping components bottom out against one another. 
     While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.