Abstract:
A fuel pump system for a fuel tank having a first and a second section has a fuel pump and a jet pump disposed in the first section. The jet pump draws fuel from the second section of the fuel tank through a transfer line and delivers it to the first section of the fuel tank. A check valve is located in the second section of the fuel tank to prohibit flow from the first section to the second section but to allow flow from the second section to the first. In this manner, the fluid is retained within transfer line so that a siphoning action can occur between the second section and the first section of the fuel tank.

Description:
FIELD 
   The present invention relates to a fuel pump system which transfers fuel between two tanks or between two sections of a single tank. More particularly, the present invention relates to an anti-siphon valve positioned in the tank or portion of the tank opposite to the fuel pump. 
   BACKGROUND 
   The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
   The designs for some vehicles limit the space available for a single section fuel tank with enough fuel capacity for the vehicle. For these vehicles, either multiple fuel tanks or multiple section fuel tanks such as saddle tanks have been developed. Typical fuel delivery systems draw fuel from a single inlet and with the incorporation of a multiple section fuel tank, either multiple fuel inlets have to be developed or systems for equalizing the fuel in the separate sections of the fuel tank need to be incorporated. 
   While systems have been developed for multiple inlets, the independent drawing of fuel from the multiple sections leads to the problem of unequal levels of fuels in the multiple sections due to unequal drawing of the fluid from each section. Systems have also been developed for transferring fuel between various sections of the fuel tank to equalize the fuel level in each section. In one system, in a saddle type fuel tank, fuel is siphoned between a fuel tank sub side and a fuel tank main side within which is located the fuel pump module, which pumps fuel to the engine of the vehicle. The siphoning action is started and maintained by having the fuel pump module pump a portion of the fuel to the fuel tank sub side to purge gas from the siphon line which then transfers fuel to the fuel tank main side when unequal levels of fuel exist. 
   In other systems, a jet pump of the fuel pump module operates to draw fuel from the fuel tank sub side to the fuel tank main side. In order to maintain an uninterrupted supply of fuel to the engine, the jet pump of the fuel pump module must be submerged in fuel at all times to maintain its primed state in order to transfer fuel from the fuel tank sub side to the fuel tank main side. If the jet pump of the fuel pump module is not maintained in a primed or submerged condition, the transfer of fuel from the tank sub side to the tank main side may not be maintained and thus, uninterrupted supply of fuel to the engine may not be maintained. 
   During instances of quick vehicle maneuvering, sloshing of fuel from the fuel tank main side to the fuel tank sub side may occur. When this occurs, an instant imbalance of fuel levels between the fuel tank main side and the fuel tank sub side occurs. While current transfer lines between two sections of a fuel tank are designed to eventually equalize the fuel levels, they do not have the fuel transfer volume capability to equalize this sloshed fuel imbalance quickly. This may result in an excess amount of fuel in the fuel tank sub side and an insufficient amount of fuel in the fuel tank main side leading to a loss of priming for the jet transfer pump. Ultimately, this may result in losing the uninterrupted supply of fuel to the engine, even though the fuel tank sub side has sufficient fuel to be transferred to the fuel tank main side. 
   In situations where fuel sloshing occurs in the opposite direction or from the fuel tank sub side to the fuel tank main side, current transfer systems will equalize the fuel levels by transferring fuel from the fuel tank main side to the fuel tank sub side. This is an unnecessary transfer since the fuel that has been transferred to the fuel tank sub side from the fuel tank main side will eventually have to be retransferred back to the fuel tank main side. 
   SUMMARY 
   The present invention provides the art with a fuel transfer system that keeps the fuel in the fuel tank main side while transferring fuel from the fuel tank sub side. Regardless of the difference in levels of the two sides of the fuel tank, once fuel has been transferred to the fuel tank main side, it is kept in the fuel tank main side. The present invention incorporates an anti-siphon valve at the fuel inlet in the fuel tank sub side to prohibit fuel flow from the fuel tank main side to the fuel tank sub side through the single fuel transfer line. 
   Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 

   
     DRAWINGS 
     The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
       FIG. 1  is a perspective view of an automobile incorporating a saddle tank and an anti-siphon valve in accordance with the present invention; 
       FIG. 2  is a perspective view of the saddle tank illustrated in  FIG. 1  including the fuel pump module and transfer system in accordance with the present invention; 
       FIG. 3  is an enlarged cross-sectional view of the fuel tank sub side module for the fuel pump module illustrated in  FIG. 2 ; 
       FIG. 4  is an enlarged cross-sectional view of the anti-siphon valve illustrated in  FIG. 3 ; 
       FIG. 5  is a schematic view illustrating one scenario of fuel levels with the fuel tank illustrated in  FIGS. 1 and 2 ; 
       FIG. 6  is a schematic view similar to  FIG. 5  but illustrating another scenario of fuel levels with the fuel tank illustrated in  FIGS. 1 and 2 ; 
       FIG. 7  is a schematic view similar to  FIG. 5  but illustrating another scenario of fuel levels with the fuel tank illustrated in  FIGS. 1 and 2 ; and 
       FIG. 8  is a schematic view similar to  FIG. 5  but illustrating another scenario of fuel levels with the fuel tank illustrated in  FIGS. 1 and 2 . 
   

   DETAILED DESCRIPTION 
   The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
   There is illustrated in  FIG. 1  a vehicle which incorporates a fuel pump module in accordance with the present invention and which is designated generally by reference numeral  10 . Some vehicles, and more specifically sports cars and sport sedans, are rear wheel drive vehicles that have a propeller shaft running between an engine located in the front of the vehicle and a transmission located in the rear of the vehicle or between a transmission located in the front of the vehicle and a differential located in the rear of the vehicle. When positioning the fuel tank in the rear of the vehicle, accommodations must be made to provide room for the propeller shaft. Typically this is accomplished by utilizing a saddle type fuel tank having a first section located on one side of the propeller shaft, a second section located on an opposite side of the propeller shaft and a bridge section connecting the first and second sections. This allows for the propeller shaft to be located between the two side sections of the fuel tank and under the bridge section of the fuel tank. With this saddle type of fuel tank, fuel needs to be drawn from each side section of the fuel tank or fuel needs to be transferred from one side section to the other side section typically through the bridge section. 
   Referring to  FIGS. 1 and 2 , vehicle  10  includes a body  12 , a set of wheels  14 , an engine  16 , a fuel tank  18  and a fuel line  20  extending between fuel tank  18  and engine  16  to supply fuel to engine  16  using a fuel pump module  22  disposed within fuel tank  18 . Fuel tank  18  is a saddle type fuel tank which includes a fuel tank main side  30 , a fuel tank sub side  32  and a bridge section  34 . Fuel tank main side  30  houses a fuel pump  36  which is a part of fuel pump module  22 . Fuel pump  36  pumps fuel from fuel tank main side  30  to engine  16  through an outlet  38  which is connected to fuel line  20 . Fuel tank main side  30  communicates with fuel tank sub side  32  through bridge section  34  and a transfer line  40  which extends from fuel tank sub side  32  to fuel tank main side  30  though bridge section  34 . 
   Referring now to  FIGS. 3 and 4 , a sub side transfer module  42  which is a part of fuel pump module  22  is illustrated. Sub side transfer module  42  includes an upper housing  44  which is connected to a lower sub side module stay  46 . Lower sub side module stay  46  is disposed at the bottom of fuel tank sub side  32  and upper housing  44  extends upward from lower sub side module stay  46  to engage a sub side cap  48  which is secured to fuel tank sub side  32 . Upper housing  44  supports various components of fuel pump module  22  such as fuel level sensors as is known well in the art. 
   Lower sub side module stay  46  comprises an outer housing  50 , an umbrella valve plate  52  and an umbrella valve  54 . Outer housing  50  rests on the bottom of fuel tank sub side  32  and it includes a fuel inlet  56  formed by a plurality of ribs  58  and fuel outlet  60  which is in communication with transfer line  40 . Umbrella valve plate  52  is a cup shaped component which is disposed within outer housing  50  to form a fluid chamber  62 . Umbrella valve plate  52  includes a plurality of ribs  64  which prevent sagging of umbrella valve plate  52  and which form a plurality of stays or hooks  66  which secure umbrella valve plate  52  to outer housing  50 . A seal  68 , such as an O-ring, seals the connection between umbrella valve plate  52  and outer housing  50  to seal chamber  62  whose lower portion acts as a water reservoir to trap condensation or water present in the fuel. Fuel outlet  60  opens into fluid chamber  62  and it can be positioned to overlap the lower portion of fluid chamber  62  which is the water reservoir such that any trapped water in the fluid reservoir will be sucked out of the reservoir when the jet pump operates. 
   Umbrella valve plate  52  defines a plurality of fuel passages  70  and a central aperture  72 . Umbrella valve  54  comprises a central shaft  74  and an umbrella seal  76 . Central shaft  74  is disposed within central aperture  72  and which includes an enlarged section  78  which retains umbrella valve  54  within central aperture  72 . Umbrella valve  54  is an elastomeric component and umbrella valve  54  is assembled within central aperture  72  by applying pressure to central shaft  74  such that enlarged section  78  is distorted and forced through central aperture  72 . Once enlarged section  78  passes through central aperture  72  it springs back to its original shape to retain umbrella valve  54  within central aperture  72 . Umbrella seal  76  extends radially out from central shaft  74  to cover and thus close the plurality of fuel passages  70 . The outer circumferential edge of umbrella seal  76  sealingly engages umbrella valve plate  52 . 
   When umbrella valve  54  is in its closed position as illustrated in  FIG. 4 , communication between fuel inlet  56  and fuel outlet  60  is prohibited. Thus, fuel flow from fuel outlet  60 , to fuel inlet  56  through chamber  62  is prohibited. Thus, fuel flow through transfer line  40  from fuel tank main side  30  to fuel tank sub side  32  is prohibited. When fuel pressure at fuel inlet  56  exceeds the fuel pressure at fuel outlet  60 , umbrella seal  76  of umbrella valve  54  will deflect to allow fuel flow through passages  70  from fuel inlet  56  to fuel outlet  60 . Thus, fuel flow through transfer line  40  from fuel tank sub side  32  to fuel tank main side  30  is permitted. Umbrella valve  54  acts as a one-way valve to allow fuel flow from fuel tank sub side  32  to fuel tank main side  30  but to prohibit fuel flow from fuel tank main side  30  to fuel tank sub side  32 . 
     FIGS. 5-8  depict various fuel transfer scenarios that typically occur in fuel tank  18 .  FIG. 5  illustrates fuel tank  18  in which fuel levels  92  and  94  are generally equal in fuel tank main side  30  and fuel tank sub side  32 . Typically fuel levels  92  and  94  illustrated in  FIG. 5  are the fuel levels experienced by vehicle  10  during steady state running of vehicle  10 . In fuel tank  18  with fuel levels  92  and  94  illustrated in  FIG. 5 , the fuel in fuel tank main side  30  is pumped to engine  16  through outlet  38  and fuel line  20 . Excess fuel pumped by fuel pump module  22  creates a jet pump, as is known in the art, to draw fuel from fuel tank sub side  32  to fuel tank main side  30  through transfer line  40 . Umbrella valve  54  will open to allow fuel flow through transfer line  40  when the fuel pressure at fuel outlet  60  is less than the fuel pressure at fuel inlet  56 . 
   As fuel is pumped from fuel tank main side  30 , the jet pump may not sufficiently move fuel from fuel tank sub side  32  to fuel tank main side  30  and the scenario in  FIG. 6  can occur. The scenario in  FIG. 6  can also occur if vehicle  10  experiences quick, hard cornering. During quick, hard cornering, fuel in fuel tank main side  30  may slosh or transfer to fuel tank sub side  32  through bridge section  34  due to lateral forces experienced during the cornering maneuver. With fuel level  92  in fuel tank main side  30  being low, the jet pump of fuel pump module  22  may not be submerged in fuel and the pumping action of the jet pump will cease. At this point, transferring of fuel between fuel tank sub side  32  and fuel tank main side  30  via siphoning becomes necessary in order to transfer fuel back to fuel tank main side  30 . In order for this siphoning action to occur, transfer line  40  must be filled with fuel. Umbrella valve  54  prohibits fuel flow through transfer line  40  from fuel tank main side  30  to fuel tank sub side  32  and thus umbrella valve  54  will ensure that transfer line  40  remains filled with fuel. 
   With fuel level  94  in fuel tank sub side  32  being higher than fuel level  92  in fuel tank main side  30  as illustrated in  FIG. 6  and transfer line  40  being filled with fuel, a siphoning action will occur to move fuel from fuel tank sub side  32  to fuel tank main side  30 . The difference in fuel levels  92  and  94  will create a pressure differential across umbrella valve  54  to open umbrella valve  54  and allow the siphoning action to occur. Fuel will continue to be siphoned from fuel tank sub side  32  to fuel tank main side  30  until the jet pump is again primed and will continue with the jet pump action until fuel levels  92  and  94  reach the levels illustrated in  FIG. 7 . 
     FIG. 8  illustrates the scenario where fuel level  92  in fuel tank main side  30  is higher than fuel level  94  in fuel tank sub side  32 . This can occur when the jet pump transfers more fuel than that used by engine  16  or when, due to cornering of vehicle  10 , lateral forces slosh or transfer fuel from fuel tank sub side  32  to fuel tank main side  30 . The higher level of fuel level  92  in comparison with fuel level  94  will create a higher pressure at fluid outlet  60  than the fuel pressure at fuel inlet  56 . Umbrella valve  54  will be urged against umbrella valve plate  52  to close fuel passages  68  and prohibit fuel transfer from fuel tank main side  30  to fuel tank sub side  32  through transfer line  40 . Thus, the fuel levels  92  and  94  illustrated in  FIG. 8  will remain. 
   The advantage of fuel levels  92  and  94  illustrated in  FIG. 8  are that fuel within fuel tank main side  30  remains ready to be pumped by fuel pump module  22  to engine  16 . Fuel from fuel tank main side  30  to fuel tank sub side  32  can only occur through bridge section  34  due to lateral forces being imposed upon vehicle  10  by cornering or by other means. Should this occur and fuel levels  92  and  94  reach the levels depicted in  FIG. 6 , transfer of fuel from fuel tank sub side  32  to fuel tank main side  30  will again occur as described above.