Abstract:
This invention provides a low profile fuel tank assembly having an elongated fuel delivery module mounted horizontally within the fuel tank and independent from a flange which covers a sole fuel tank access hole. An integrated fuel pump and associated motor of the module dictates the length of the module. The motor and pump has a rotational axis disposed substantially horizontal within the fuel tank. Because the fuel delivery module is supported by the fuel tank shell or bottom, independent of the flange, the access hole can be located anywhere on the fuel tank in order to simplify fuel tank ingress and minimize repair procedures. During assembly, the module is preferably inserted into the fuel tank through the access hole, and is then slide and snap-locked into a bracket welded to the bottom of the fuel tank.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to a fuel tank assembly and more particularly to a fuel tank assembly having a low profile fuel delivery module.  
         BACKGROUND OF THE INVENTION  
         [0002]    Traditionally, fuel tank assemblies have a fuel tank with an access hole covered by a flange. An elongated fuel delivery module is carried by and projects downward from the flange, stopping just short of or bearing on the fuel tank bottom. The overall length of the module is generally dictated by an electrical motor and fuel pump disposed in series along a vertical rotational axis. The vertical module length dictates the depth or minimum vertical height of the fuel tank or reservoir. Therefore, the optimum profile of the fuel tank is limited by the vertical length of the fuel delivery module. And, to optimize the already restricted profile, the tank access hole must be located on an upper horizontal surface, and most probably, the highest elevated surface of the fuel tank.  
           [0003]    Locating the access hole on top of the tank is seldom the preferred location for maintenance purposes since the tank must be removed from the vehicle prior to accessing the internal components of the fuel tank assembly through the access hole. Because the fuel delivery module is cantilevered from the flange, the flange and the interconnection to the fuel tank itself must be robust and designed so as to pass high speed vehicle crash tests which create high torque or torsional forces upon the flange. The larger the flange, the more likely the flange seal will fail. Unfortunately, much of the available flange surface area is occupied by the fuel delivery module so that use of the flange surface area for other component mountings, or penetrations into the fuel tank, is limited.  
         SUMMARY OF THE INVENTION  
         [0004]    This invention provides a low profile fuel tank assembly having an elongated fuel delivery module mounted generally horizontally within the fuel tank independent of a flange which covers a sole fuel tank access hole. An integrated fuel pump and associated electric motor of the module has a rotational axis disposed substantially horizontal within the fuel tank. Because the fuel delivery module is supported by the fuel tank shell or bottom, independent of the flange, the access hole can be located anywhere on the fuel tank in order to simplify fuel tank ingress and minimize repair procedures. During assembly, the module is preferably inserted into the fuel tank through the access hole, and is then slid and snap-locked into a bracket attached to the bottom of the fuel tank.  
           [0005]    Preferably, the fuel delivery module slides along interlocking rails formed on both sides of the module into the mounting bracket between a clasp of the bracket and a support structure of the module. Preferably, a forward tang of the bracket prevents the module from sliding too far forward. The module snaps locks in place with the bracket, preventing rearward movement and disengagement, via an upward projecting locking tab of the bracket and a forward projecting snap clip of the support structure which resiliently engages the locking tab.  
           [0006]    Objects, features and advantages of this invention include providing a low profile fuel tank assembly thereby reducing surrounding design restraints of a vehicle fuel tank and the vehicle using it, simplifying fuel system maintenance procedures by enabling easier fuel tank ingress, reducing flange size to improve sealing, freeing up flange surface area for additional component penetrations into the fuel tank, and reducing fuel permeation while providing a relatively simple, design and a low cost rugged, durable, and reliable fuel delivery module and tank assembly. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0007]    These and other objects, features and advantages of this invention will be apparent from the following detailed description, appended claims, and accompanying drawings in which:  
         [0008]    [0008]FIG. 1 is a perspective view of a fuel delivery module and tank assembly with part of the fuel tank broken away and in section to show internal detail;  
         [0009]    [0009]FIG. 2 is a perspective view of a fuel delivery module, mounting bracket and a flange of the assembly of FIG. 1;  
         [0010]    [0010]FIG. 3 is a section view of the fuel delivery module and mounting bracket taken along line  3 - 3  of FIG. 1;  
         [0011]    [0011]FIG. 4 is a front end perspective view of the fuel delivery module and bracket;  
         [0012]    [0012]FIG. 5 is a perspective view of the bracket;  
         [0013]    [0013]FIG. 6 is an exploded partial cross section view of the fuel delivery module and bracket taken along line  6 - 6  of FIG. 3;  
         [0014]    [0014]FIG. 7 is a perspective view of the fuel delivery module and bracket with part of a fuel filter broken away to show internal detail;  
         [0015]    [0015]FIG. 8 is a section view of the fuel delivery module and bracket taken along line  8 - 8  of FIG. 2; and  
         [0016]    [0016]FIG. 9 is a section view of the fuel delivery module and bracket taken along line  9 - 9  of FIG. 3. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]    Referring in more detail to the drawings, FIG. 1 illustrates a fuel tank assembly  10  having a fuel tank  12  with an access hole  14 , being large enough, so that an elongated fuel delivery module  16  can be inserted into a fuel chamber  13  defined by the fuel tank  12 . A leading end  18  of the module  16  is positioned in front of a receiving end of an elongated bracket  20  welded to a bottom surface or wall  22  of an inner surface  23  of the fuel tank  12 . The bracket  20  and module  16  can be located on any other inner surface of the fuel tank  12 ; however, positioning the module on the bottom surface eliminates the need for a pump inlet tube which could contribute toward fuel vapor lock. Also, because the longitude of the module  16  is horizontal the shape of the fuel tank  12  is enabled to have a low profile, not otherwise available. The fuel tank  12  is preferably made of a blow molded plastic or high density polyethylene, HDPE, and the bracket  20  is made of an injected plastic or HDPE. Being of substantially like material, the plastic bracket  20  is welded to the inner surface  23  of the bottom wall  22 , likewise, in a substantially horizontal position. The access hole  14  is covered and sealed or closed by a flange  24  as best shown in FIG. 2.  
         [0018]    Traditionally, the access hole  14  is positioned at the upper most part of the fuel tank  12  because the fuel delivery module is commonly mounted in a vertical direction and carried by the flange. Since the fuel delivery module  16  of the present invention is not carried by the flange  24 , the access hole  14  can be located any where on the fuel tank  12 . In fact, the access hole  14  can easily be located through any side of the fuel tank  12 . Such positioning options are desirable to facilitate fuel tank assembly, maintenance and repair. Aside from the vertical mounting and flange support of traditional assemblies, the module  16  of the present invention can be identical to the fuel pump assembly described in Bucci et al., U.S. Pat. No. 4,860,714 and incorporated herein by reference.  
         [0019]    Referring to FIGS.  2 - 5 , in assembly, the fuel delivery module  16  is slidably received between opposing clasps  26  which project upward from a substantially planar base plate  30  of the bracket  20  and into the fuel chamber  13  defined by the fuel tank  12 . The base plate  30  is welded, embedded, or otherwise attached to the substantially horizontal bottom wall  22  of the fuel tank  12  and extends from a forward portion  34  to a rearward portion  32 . When utilizing HDPE fuel tank shells having multi-layers with an intermediate fuel permeation barrier layer, not shown, it is preferable not to breach the permeation barrier layer when securing the bracket  20  to the fuel tank  12 . Therefore, welding to the bottom surface  22  or inner layer of the multi-layered fuel tank is a preferred method of attachment. Another method, not shown, is to mold protrusions within the fuel tank during the tank manufacturing blow molding process. The bracket  20 , or the module  16  directly, can then be press fitted to the protrusions.  
         [0020]    Referring to FIGS.  4 - 6 , when assembled, the clasps  26  prevents upward movement of the fuel delivery module  16  away from the base plate  30 , via an elongated guideway  36  of each clasp  26  which slideably engages an interlocking rail  38  of the fuel delivery module  16 . The guideways  36  and rails  38  extend longitudinally between the forward and rearward portions  34 ,  32  of the bracket  20 . Preventing the module  16  from moving excessively forward and disengaging from the guideways  36  and rails  38  is a stop tang  40  projecting unitarily upward from the base plate  30  and being engageable with the leading end  18  of the fuel delivery module  16 . In assembly, rearward movement of the fuel delivery module  16  with respect to the bracket  20 , which could otherwise disengage the interlocking guideways and rails  36 ,  38  in the rearward direction, is prevented by locking tabs  42  of the bracket  20  which project upward from each clasp  26  and a pair of snap clips  44  of the fuel delivery module  16  which engage the locking tabs  42 . The clasps  26  are generally somewhat flexible in order to act as bottom referencing springs which are capable of absorbing bottom impact loads placed upon the fuel tank  12 .  
         [0021]    As best illustrated in FIGS. 3, 5 and  6 , the guideways  36  of each of the laterally opposed clasps  26  each have a channel  54  defined by a rail  48  extending longitudinally of the bracket and fixed at a right angle to a cross bar  47  attached to the upper edge of a substantially planar wall  46  which projects perpendicularly upward from the base plate  30  and extends longitudinally lengthwise of the bracket  20 . The rail  48  projects downward toward the base plate  30  from a longitudinal extending edge of the cross bar  47  and extends parallel to the wall  46 . In assembly each channel  54  receives and interlocks with one of the upward projecting rails  38  of a support structure or can  52  of the fuel delivery module  16 . The rail  38  extends longitudinally, projects upward, and along its lower edge is fixed to a traverse spacer bar  56  attached to the can  52 . Preferably the can has a side surface  50  which is spaced from and extends parallel to the rail  38  to define therewith a channel or slot  58  in which the rail  48  is disposed when the fuel delivery module  16  is engaged to the bracket  20 .  
         [0022]    Referring to FIGS. 3 and 6, the snap clips  44  are attached each to one of both longitudinal sides  50  of the can  52 . The snap clips  44  are disposed over and are spaced vertically above the rails  38  of the can  52  so that the bar  47  of the clasp  26  on the bracket  20  can fit there-between. Each snap clip  44  has a catch or lip  64  on one end of a flexible arm  64  with its other end cantilevered and attached by a base  60  to the longitudinal side  50  of the can  52 . The base  60  serves to support and space the cantilevered arm  62  laterally outward from the longitudinal side  50 . The cantilevered arm  62  is disposed substantially parallel to the longitudinal side  50  and projects in a forward direction, as best shown in FIG. 2. The lip  64  projects laterally outward with respect to the arm  60  and the longitudinal side  50 . As the fuel delivery module  16  slides into the bracket  20 , the locking tab  42  causes the cantilevered arm  62  of the snap clip  44  to flex inward toward the longitudinal side  50  of the can  52  and the lip  64  to slide along an inner surface of the locking tab  42 . The cantilevered arm  62  snaps back or unflexes when the lip  64  slides past the locking tab  42  to overlap and engage a forward facing stop surface  66  of the locking tab  42 . Abutment of the lip  64  of the snap clip  44  with the stop surface  66  of the locking tab  42  prevents the fuel delivery module  16  from moving rearward and disengaging from the interlocking guideways  36  and rails  38 . To permit removal of the fuel delivery module  16  from the bracket  20 , a lateral inward force is applied to the arms  62  of the snap clips  44  (which extends vertically above the locking tab  42 ). When this disengaging lateral force is applied to both clips, the lips  64  separate from their respective locking tabs  42  permitting the fuel delivery module to slide rearwardly.  
         [0023]    During assembly, alignment of the fuel delivery module  16  for insertion between the opposing clasps  26  is guided by angled or inclined guide plates  68  of the clasps  26 . Each guide plate  68  is substantially planar, angled outward and projects rearward from both the rear vertical edge of the locking tab  42  and the rear edge of the wall  46  of its associated clasp  26 . The combination of both guide plates  68  of the clasps  26  forms a type of funnel which helps to guide and align the fuel delivery module  16  between the opposing clasps  26 . The bar  47  reinforces the guide plate  68  by extending rearward to and engaging a midsection of the guide plate  68 .  
         [0024]    As further illustrated in FIGS.  7 - 9 , the can  52  of the fuel delivery module  16  carries a fuel supply pressure control assembly  70  which is illustrated as a pressure control regulator mounted to the outlet of a fuel pump and motor  72  having a rotational axis  74  disposed substantially horizontal and preferably slanted not more than ten degrees from an imaginary horizontal plane when the fuel tank is in its normal orientation within the vehicle. However, the pressure control assembly  70  can also be a pressure transducer motor speed control system where a fuel pressure transducer feeds back to a variable speed fuel pump. An advantage of this system is that less energy is consumed since the pump does not run at full system voltage all the time as does the pressure regulator.  
         [0025]    Fuel flows from a reservoir carried by the can  52  via the fuel pump and motor  72  disposed within the can  52 . From pump  72 , the fuel flows through an elongated fuel filter  75  of the module  16  and to the regulator  70 , as best shown in FIG. 8. The filter  75  partially wraps about the pump and motor  72  and has a fuel inlet nozzle  82  mounted to an end of the filter  75  which is opposite or away from the regulator  70 . A fuel level sensor assembly  77 , which includes a pivoting float arm sensor  78  and/or a fuel piezo level sensor  76 , are integral to the module  16 . The pivoting float arm sensor  78  functions off a fixed ohm resistor card with variable resistance controllable by a float engaged to the distal end of a pivoting arm.  
         [0026]    Various attachments on the module  16  lead to and extend through the flange  24 . These attachments include a wiring harness (not shown) and a flexible tube  80  for supplying fuel to the engine and which communicates with the regulator  70  via a nozzle  81  engaged unitarily to the can  52 . Because flange  24  of the present invention does not carry or support the fuel delivery module  16 , other components are easily supported by the flange  24 . These components include, but are not limited to, an on-board diagnostic-two pressure transducer, OBD 2 , for detecting fuel tank leakage via pressure differential, and a fill limit vent valve, FLVV.  
         [0027]    While the forms of the invention herein disclose constitute a presently preferred embodiment, many others are possible. For instance, the opposing clasps  26  can be replaced with a strap which wraps around the module  16  and engages the base plate of the alternative bracket at either end. It is not intended herein to mention all the equivalent forms or ramifications of the invention, it is understood that the terms used herein are merely descriptive rather than limiting and that various changes may be made without departing from the spirit or scope of the invention.