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 preferably 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 inserted into the fuel tank through the access hole, and is then placed and snap-locked preferably into a bracket structure permanently engaged to an inside surface of the fuel tank.

Description:
REFERENCE TO RELATED APPLICATION 
     This is a continuation-in-part application of U.S. patent application Ser. No. 09/997,907,filed Nov. 30, 2001 now abandoned. 
    
    
     FIELD OF THE INVENTION 
     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 
     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. 
     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 
     This invention provides a low profile fuel tank assembly having a preferably 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 preferably 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 secured to a bracket or strap assembly attached to the inside surface of the fuel tank, preferably via laser welding. 
     Preferably, the fuel delivery module is inserted into the bracket directly adjacent to a base plate of the bracket secured to the inner bottom of the tank. During assembly, the fuel delivery module is centered laterally upon the base plate of the bracket by two opposing sides projecting upward from the base plate. The module is preferably also centered longitudinally upon the base plate by two pairs of opposing stop tabs projecting upward from end edges of the base plate. 
     In a first embodiment of the bracket, the fuel delivery module engages the bracket by sliding horizontally along interlocking rails formed on both sides of the module and into the mounting bracket between a clasp of the bracket and a support structure of the module. Preferably, a forward tab of the bracket prevents the module from sliding too far forward. The module snap 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. 
     In a second embodiment of the bracket, the base plate is part of a resilient tray which engages at least one resilient strap at both ends of the strap. The bracket is designed to reduce shear forces placed upon the welds between the tank and the base plate during impact scenarios. To do this, the fuel delivery module is encircled by the tray and the strap. The strap is in tension when extended over and engaged directly to the fuel delivery module and a clearance exists between the module and the sides or curbs of the tray permitting some movement of the module with respect to the bracket. 
     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 
       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: 
         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; 
         FIG. 2  is a perspective view of a fuel delivery module, mounting bracket and a flange of the assembly of  FIG. 1 ; 
         FIG. 3  is a section view of the fuel delivery module and mounting bracket taken along line  3 — 3  of  FIG. 1 ; 
         FIG. 4  is a front end perspective view of the fuel delivery module and bracket; 
         FIG. 5  is a perspective view of the bracket; 
         FIG. 6  is an exploded partial cross section view of the fuel delivery module and bracket taken along line  6 — 6  of  FIG. 3 ; 
         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; 
         FIG. 8  is a section view of the fuel delivery module and bracket taken along line  8 — 8  of  FIG. 2 ; 
         FIG. 9  is a section view of the fuel delivery module and bracket taken along line  9 — 9  of  FIG. 3 ; 
         FIG. 9A  is a perspective view of a second embodiment of a fuel delivery module, bracket and tank assembly with part of the fuel tank broken away and in section to show internal detail; 
         FIG. 9B  is a perspective view of the second embodiment of the bracket illustrated in an open position; and 
         FIG. 9C  is a perspective view of the second embodiment with the fuel delivery module placed within the bracket and the bracket illustrated in an open position. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     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 . 
     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. 
     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. 
     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 tab  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 . 
     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 . 
     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. 
     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 . 
     As further illustrated in  FIGS. 7-8 , 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. 
     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. 
     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, OBD2, for detecting fuel tank leakage via pressure differential, and a fill limit vent valve, FLVV. 
     Referring to  FIGS. 9A-9C , a second embodiment of a fuel delivery assembly  10 ′ is useful in absorbing shock, or G-forces, therefore relieving stress placed upon the tank to bracket interface and the fuel module to bracket interface. The strapped bracket  20 ′ allows the fuel delivery module  16 ′ to move slightly in any direction which acts to decelerate the module over a longer time period than the stiffer first embodiment during high impact scenarios. 
     Laser welds  90 , which require no special tank features or contours, secure a substantially planar base plate  30 ′ of a base unit or tray  89  of the bracket  20 ′ to the inner surface  23 ′ of the fuel tank  12 ′. There are four welds  90  illustrated in  FIG. 9B , however, there may be more or less depending upon the weight of the fuel delivery module  16 ′ and the configuration of the fuel tank assembly  10 ′. The tray  89  is preferably made of like material to the inner surface  23 ′ of the fuel tank  12 ′. As one example, if the fuel tank is HDPE, preferably, the tray  89  is also made of HDPE to enhance the strength of the weld. However, because HDPE has a tendency to swell when soaked with hydrocarbon fuel, the tray  89  should also be reinforced with integral glass fibers to reduce swelling. The laser weld  90  is preferred over plate welding because the tray  89  is designed to flex and is too thin to handle the high heat produced during the plate welding process. Laser welding is also advantageous because the laser weld equipment permits off-setting the bracket  20 ′ away from the tank access hole  14 ′. This off-set can generally be as great as six to twelve inches for a typical automotive fuel tank application. Fiber optics are used to locate the weld between the bracket  20 ′ and the tank  12 ′. When utilizing a laser light wavelength of approximately 800 nm, the welding process takes about three to five seconds. 
     Initially locating the fuel delivery module  16 ′ to the bracket  20 ′ are first and second side guide plates or side curbs  92 ,  94  of the tray  89  which substantially oppose one-another, performing similarly to the guide plates  68  of the first embodiment. The side curbs  92 ,  94  project substantially upward from respective longitudinal edges of the base plate  30 ′, and extend longitudinally of the base plate  30 ′ between forward and rearward stop tabs  96 ,  98  of the tray  89 . The forward stop tabs  96  function similarly to the stop tab  40  of the first embodiment, limiting forward movement of the fuel delivery module  16 ′ within the bracket  20 ′. The forward stop tabs  96  extend inward toward one-another from respective ends of the curbs  92 ,  94  and along a minor portion of a lateral or forward edge  100  of the base plate  30 ′. The additional rearward stop tabs  98  of the second embodiment limit rearward movement of the fuel delivery module  16 ′ within the bracket  20 ′, and extend inward toward one-another along a minor portion of a rearward edge  102  of the base plate  30 ′ from respective ends of curbs  92 ,  94 . 
     After the base plate  30 ′ of the tray  89  is laser welded to the tank  12 ′, an elongated support structure or can  52 ′ of the elongated fuel delivery module  16 ′ is placed into the tray  89  from a substantially vertical direction. The forward and rearward stop tabs  96 ,  98  align the can  52 ′ longitudinally to the tray  89 , and the first and second curbs  92 ,  94  align the can  52 ′ laterally to the tray  89 . 
     A resilient forward and rearward pair of straps  104 ,  106 , secure the module  16 ′ resiliently and directly against the welded base plate  30 ′. Each pair of straps  104 ,  106  has a long mid strap  108  and a shorter end strap  110  which extend snugly and resiliently over a contoured fuel filter  75 ′ of the module  16 ′ engaged to the can  52 ′. Preferably, opposite ends  112 ,  114  of the straps  108 ,  110  of both pairs extend between and are engaged unitarily to a first and a second flap  116 ,  118 . The first flap  116  is illustrated as being hinged unitarily to a raised portion  120  of the first curb  92  along an axis disposed longitudinally of the base plate  30 ′. The second flap  118  snap locks to a raised portion  122  of the second curb  94  via a snap locking feature, or two respective apertures  126  communicating through the second flap  118  which snugly receive two protuberances  124  projecting outward from the second raised portion  122 . A thumb catch  128  projects outward from the second flap  118  between the apertures  126  to assist the user in snap locking the second flap  118  and straps  108 ,  110  from an open position  130  to a closed or locked position  132 . 
     Because the bracket  20 ′ is illustrated as one unitary part, the straps  108 ,  110  are made of the same material as the base plate  30 ′ which is preferably HDPE. The straps must be thin enough to enable stretching across the fuel filter  75 ′ thus providing a degree of give or resilience. The thickness of the strap necessary to achieve this resilience is thus dependent upon the material used. 
     Alternatively, the straps  108 ,  110  and the flaps  116 ,  118  can be unitary with each other, yet separate as a single molded unit from the base plate  30 ′. With this configuration, the first flap  116  has a snap locking feature instead of the resilient hinge. As a separate entity, the straps and flaps can be made of a material with excellent elastic properties yet different than the material of the base plate  30 ′ which must be similar to the tank  12 ′ material for welding purposes. One such material for the straps and flaps is nylon. 
     As presently illustrated, the fuel filter  75 ′ of the fuel delivery module  16 ′ is supported by and protrudes upward from the can  52 ′. A substantially outward facing contoured surface  134  of the filter  75 ′ disposed above the can  52 ′ is in direct contact with the resilient straps  108 ,  110 . The contoured surface  134  has a forward shelf or shoulder  136  which substantially lies within an imaginary plane disposed perpendicular to the base plate  30 ′. The forward shelf  136  is contiguously defined between and disposed substantially perpendicular to a leading proximal portion  138  of the contoured surface  134  and a distal mid portion  140 . The short strap  110  of the forward pair  104  is resiliently engaged directly to the leading proximal portion  138  of the contoured surface  134 . The longer mid strap  108  of the forward pair is directly engaged resiliently to the distal mid portion  140  disposed generally further away from the base plate  30 ′ than the forward proximal portion  138 . During high impact scenarios, the forward shelf  136  will contact the short strap  110  of the forward pair  104  thereby limiting the forward movement of the fuel delivery module  16 ′ within the bracket  20 ′. 
     Likewise, the contoured surface  134  of the fuel filter  75 ′ has a rearward shelf  142  which lies within an imaginary plane disposed substantially parallel to the forward shelf  136 . The rearward shelf  142  is defined contiguously between and disposed substantially perpendicular to a trailing proximal portion  144  of the contoured surface  134  and the distal mid portion  140 . The short strap  110  of the rearward pair  106  is resiliently engaged directly to the trailing proximal portion  144  of the contoured surface  134 . The longer mid strap  108  of the rearward pair  106  and the longer mid strap  108  is directly engaged resiliently to the distal mid portion  140 . During high impact scenarios, the rearward shelf  142  will contact the stretchable short strap  110  of the rearward pair  106  thereby limiting the rearward movement of the fuel delivery module  16 ′ within the bracket  20 ′. Depending upon dynamics of the environment and the shape and weight distribution of the fuel delivery module  20 ′ other strap configurations can also suffice. For instance, one short strap may secure the module by engaging the filter&#39;s contoured surface from within a channel defined by the surface  134 . 
     Referring to  FIG. 9C , movement of the fuel delivery module  16 ′ with respect to the base plate  30 ′ and the laser welds  90  is limited to about two millimeters for a typical automotive fuel tank application. With the fuel delivery module  16 ′ centered longitudinally to the base plate  30 ′ by the tight relationship between the short straps  110  and the forward and rearward shelves  136 ,  142 , a clearance  146  of approximately two millimeters exists between can  52 ′ and the forward tabs  96 , and the can  52 ′ and the rearward tabs  98 . To assist in similar, but lateral movement, a clearance  148  of approximately two millimeters exists between the can  52 ′ and the first curb  92 , and the can  52 ′ and the second curb  94  of the base plate  30 ′ when in an un-flexed state. Of course with the second flap  118  snap locked to the raised portion  122 , the clearance  148  is effectively eliminated at the raised portion  120 ,  122  junctures. 
     Also to assist in flexing of the tray  89 , two cut-outs  150  communicate through and extend laterally across the base plate  30 ′ and partially upward communicating through each side curb  92 ,  94 , but stopping short of the raised portions  120 ,  122 . 
     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.