Abstract:
In a fuel pump module of a vehicle fuel tank, a check valve has a counter-balanced inlet door that uses a counterweight to assist in opening the inlet door to control the flow of fuel into and out of the jet pump tube of the fuel pump module. The inlet door has a longitudinal body, a first and second pivot arm on opposing sides of the body for the door to pivot, a circular or semi-circular door portion having a through hole to secure a sealing member to the inlet door. The door portion and counterweight are at opposing ends of the body. When the inlet door rotates to its closed position, the sealing member creates a seal with the end of the jet tube. At least one straight peripheral edge about the otherwise curved door portion prevents the door portion from interfering with surrounding structure during operation.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to fuel pump modules, and more specifically, to a counter-balanced inlet door of a fuel pump module check valve.  
       BACKGROUND OF THE INVENTION  
       [0002]     Automobiles commonly employ a fuel pump module within a fuel tank, the fuel pump module having a jet pump tube inlet door that acts in concert with a jet pump tube wall to form a check valve. Quite commonly, when the fuel pump module has voltage applied to it and the fuel tank has sufficient fuel, a fuel module jet pump at one end of the jet pump tube pumps the liquid fuel to force open the jet pump tube inlet door at the opposite end of the jet pump tube. The liquid fuel subsequently flows through the jet pump tube, opens the inlet door, and is then pumped to the engine to carry out combustion.  
         [0003]     In some situations, however, the driver of a vehicle may allow the fuel level within the fuel tank to drop such that the vehicle “runs out of gas.” When this occurs, the fuel has been exhausted from the jet pump tube so that the jet pump will not assist in circulating fuel by opening the inlet door. Additionally, there is no fuel to surround the fuel pump module to provide hydrostatic force against the inlet door to open the inlet door of the jet pump tube. In this situation, even if voltage is applied to the fuel module, fuel is not able to open the jet pump tube inlet door and permit fuel to enter the jet pump tube. The consequence of this situation is that the vehicle is in need of a large quantity of fuel in the fuel tank to permit the inlet door of the jet pump tube to open so that fuel can fill the jet pump tube and be pumped to the engine when the fuel module is energized.  
         [0004]     There are other situations when limitations present themselves. For instance, a situation in which the engine may not be capable of being restarted is when the level of fuel within the fuel tank drops to a particularly low level, but the tank is not empty, and there is no fuel in the jet pump tube. For instance, even when a vehicle is sitting on a level surface, there may not be enough fuel in the fuel tank to surround the fuel pump module inlet door and provide enough hydrostatic force against the inlet door to open it and permit fuel to enter the jet pump tube of the fuel pump module. In this situation, since the fuel in the jet pump tube has already been pumped to the engine, fuel is not capable of being supplied to the jet pump tube, even though there is a small amount of fuel in the fuel tank. The consequence of this is that the vehicle is in need of a larger quantity of fuel in the fuel tank to cause a greater hydrostatic force against the inlet door of the jet pump tube so that the inlet door will open and permit the jet pump tube to fill with fuel.  
         [0005]     Another limitation exists when the fuel has been completely exhausted from the jet pump tube and the inlet door of the jet pump tube has closed, but there is fuel in the fuel tank; however, because the vehicle is not sitting on a level or nearly level surface, the distribution of the fuel in the fuel tank prevents the fuel from reaching or from sufficiently surrounding the jet pump tube inlet door and thus, from providing a hydrostatic force against the inlet door to open the inlet door and permit fuel to flow into the jet pump tube. In this situation, the engine is incapable of being restarted. To restart the engine, the vehicle must be repositioned to permit the fuel existing in the tank to surround the inlet door in such a quantity as to force open the inlet door.  
         [0006]     In yet another limitation, a vehicle may run out of fuel while being driven resulting in the vehicle having to be refueled at the side of a road or wherever the vehicle is when it runs out of fuel. In this unplanned event, the vehicle may be stopped on a slanted shoulder, median or on uneven off-road terrain. In order to refuel the vehicle, one or two gallons of fuel may be carried to the vehicle in a portable container from a filling station. Because of the tilted position of the vehicle, the fuel is prevented from filling the jet pump tube due to the inability of the fuel to hydrostatically force open the jet pump tube inlet door that covers the jet pump tube inlet opening, which provides access to the fuel pump module. This inability of the fuel to reach the fuel pump module jet pump tube prevents fuel from being pumped to the engine and thus, the restarting of the engine. Although the fuel may be capable of reaching and even partially surrounding the jet pump tube inlet door, the level of fuel may not be high enough to effectively provide enough force against the inlet door to open it and permit fuel to enter the jet pump tube. A device of the prior art that suffers from the above limitations is depicted in  FIGS. 9 and 10 .  
         [0007]     What is needed then is a device that does not suffer from the above limitations. This in turn, will provide a device that is capable of permitting additional liquid fuel to enter a jet pump tube, when an insufficient amount of fuel is present in the jet pump tube, by using hydrostatic force to cause a moment great enough about a door pivot point to open the jet pump tube inlet door. Furthermore, a device will be provided that permits liquid fuel to enter the fuel pump module jet pump tube when a vehicle and its fuel tank are positioned at an angle with respect to a surface on which the vehicle is sitting and hydrostatically force open the jet pump tube inlet door. In all events, the jet pump tube inlet door will be forced open when a minimum amount of fuel is introduced into the fuel tank when the vehicle is positioned on a level surface or at an angle to the surface on which the vehicle is sitting.  
       SUMMARY OF THE INVENTION  
       [0008]     In accordance with the teachings of the present invention, a fuel pump module check valve inlet door that permits liquid fuel to enter the jet pump tube when a prescribed minimum amount of liquid fuel is poured into a vehicle&#39;s empty, or nearly empty, tank is disclosed. Additionally, the fuel pump module check valve inlet door will be counter-balanced to assist the hydrostatic force of the fuel in creating a moment to open the jet pump tube inlet door when the fuel level in the tank is at a minimum. Furthermore, the fuel pump module counter-balanced inlet door will be buoyed by the liquid fuel being poured into the tank to supplement the moment to open the inlet door and permit the passage of fuel into the jet pump tube. Finally, the fuel pump module counter-balanced inlet door will permit fuel to enter the jet pump tube even when a vehicle employing the counter-balanced inlet door is parked on a sloped surface such as a shoulder of a road.  
         [0009]     In one preferred embodiment, the fuel pump module check valve inlet door has an elongated body, a first pivot arm and a second pivot arm attached to the body to permit rotation about the arms, a door portion attached to a first end of the body and a counterweight attached to the opposite end of the body. The door portion in this first preferred embodiment is semi-circular with straight edges about its periphery. In a second preferred embodiment, the fuel pump module check valve inlet door is essentially circular. In each embodiment, a door seal abuts a wall surface to create the check valve.  
         [0010]     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0012]      FIG. 1  is a perspective view of a vehicle showing the location of a fuel tank within the vehicle and a fuel module within the fuel tank, according to teachings of the present invention;  
         [0013]      FIG. 2  is a perspective view of the fuel module depicted in  FIG. 1 , according to teachings of the present invention;  
         [0014]      FIG. 3  is a perspective view of the fuel tank depicted in  FIG. 1 , showing the location of the fuel module in the fuel tank;  
         [0015]      FIG. 4  is a rear view of the vehicle depicted in  FIG. 1  showing the location of the fuel pump module inlet door relative to the fuel level within the fuel tank when the vehicle is positioned on a slope, according to teachings of the present invention;  
         [0016]      FIG. 5  is a perspective view of the counter-balanced inlet door of the fuel pump module check valve, according to teachings of a first preferred embodiment of the present invention;  
         [0017]      FIG. 6  is a perspective view of the counter-balanced inlet door of the fuel pump module check valve according to teachings of a second preferred embodiment of the present invention;  
         [0018]      FIG. 7  is a partial cross-sectional view of the fuel pump module check valve showing the counter-balanced inlet door in a closed position according to teachings of the present invention;  
         [0019]      FIG. 8  is a partial cross-sectional view of the fuel pump module check valve showing the counter-balanced inlet door in an open position according to teachings of the present invention;  
         [0020]      FIG. 9  is a perspective view of the fuel pump module reservoir depicting the location of the fuel pump module check valve according to teachings of the present invention;  
         [0021]      FIG. 10  is a perspective view of a fuel pump module check valve inlet door of the prior art; and  
         [0022]      FIG. 11  is a partial cross-sectional view of the fuel pump module check valve and inlet door of the prior art.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0023]     The following description of the preferred embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. With reference to  FIGS. 1-9 , description of a counter-balanced inlet door and associated check valve for a fuel pump module will be described.  
         [0024]      FIG. 1  depicts a vehicle such as an automobile  10  in which a fuel pump module  20  is installed within a fuel tank  30  of the automobile  10 . In this arrangement, the fuel pump module  20  is normally submerged in or surrounded by liquid fuel within the fuel tank  30  when the fuel tank  30  possesses liquid fuel. The fuel pump module  20  pumps fuel to the engine  12  via a fuel line  14 .  
         [0025]      FIG. 2  is a perspective view of the fuel pump module  20  having a reservoir  22  in which a fuel inlet  24  is located at one of its corners. The fuel module  20  is normally installed such that the top of the fuel module  20  is exposed outside of the top of the fuel tank  30  and the balance of the fuel module  20  is positioned within the fuel tank  30 . The fuel inlet  24  into the reservoir  22  is located on a side at the bottom of the reservoir  22  and permits fluid communication between the fuel module  20  and liquid fuel located outside of the reservoir  22  at the bottom of the fuel tank  30 . Because of the location of the fuel inlet  24  relative to the bottom of the fuel tank  30 , fuel is capable of entering the reservoir  22  when the fuel level is at a low level within the fuel tank  30 .  
         [0026]      FIG. 3  is an example of the fuel tank  30 , indicating as a void, the location  32  that the fuel pump module  20  occupies when the fuel pump module  20  is installed in the fuel tank  30 . The location of the fuel pump module  20  may vary within the fuel tank  30  depending upon the geometry of the fuel tank  30 , the depth of the fuel pump module  20 , and other factors.  
         [0027]      FIG. 4  depicts a rear view of the automobile  10  shown in  FIG. 1  and shows the fuel pump module  20  installed within the fuel tank  30 . Additionally, the cross-section of the inlet  34  of the fuel pump module  20  is shown below the level of liquid fuel  36  in the fuel tank  30 . As depicted in  FIG. 4 , the inlet  34  is entirely submerged ender the liquid fuel level  36  at the same time that the vehicle  10  is shown parked at an angle noted by “X” degrees. The angle X may range from zero (0) degrees to four (4) degrees (7% slope), or actually, to an even higher degree (greater slope) and still achieve the desired submergence of the inlet  34  below the liquid fuel level  36 . The actual angle depends upon how the fuel pump module  20  is situated in the fuel tank, the design of the fuel tank  30 , the level of fuel in the fuel tank  30 , and associated variables.  
         [0028]     Turning to  FIGS. 5, 7  and  8 , an example of the counter-balanced inlet door  40  for a fuel pump module  20  check valve  67 , according to the teachings of the first embodiment will be described.  FIG. 5  depicts the counter-balanced inlet door  40  of the first embodiment, while  FIGS. 7 and 8  depict closed and open positions, respectively, of the inlet door  40  and check valve  67 . The counter-balanced inlet door  40  has a door portion  52  that abuts against a jet pump tube sealing surface  60  of the jet pump tube  62  when the counter-balanced inlet door  40  is in its closed position. A resilient door seal  54  is fastened to the door portion  52  by a resilient fastening portion  56  of the door seal  54 . The resilient door seal  54  and the resilient fastening portion  56  are one piece in the present embodiment and are made from the same material. The door seal  54  and resilient fastening portion  56  are normally manufactured from a flexible material such as rubber that is capable of compressing and sealing against the jet pump tube sealing surface  60 . However, the door seal  54  may be made of any material capable of forming a seal with the jet pump tube sealing surface  60  and of existing in a liquid fuel environment. The liquid fuels are normally grades of gasoline, but may include diesel fuel or other fuels such as kerosene. The door portion  52  in the present embodiment is made of a plastic that is capable of existing in a liquid fuel environment, but the door portion  52  may be made of a lightweight metal or other non-plastic material.  
         [0029]     Maintaining reference to  FIGS. 5 and 7 , the door seal  54  abuts against the jet pump tube sealing surface  60  when the counter-balanced inlet door  40  is in its closed position. The fastening portion  56  passes through the door portion  52  in order to secure the door seal  54  to the door portion  52 . The door portion  52  is connected to a door body  44 . The door body  44  has several web portions  58   a ,  58   b ,  58   c  that provide strength to the body  44 . At the end opposite to the door portion  52 , a counterweight  42  is attached. The counterweight  42  is a weight that counters the weight of the door portion  52  with respect to pivot posts  65 ,  66  of the jet pump tube  62 . The entire counter-balanced inlet door  40  has a first pivot arm  46  having a first pivot pad  47 , and a second pivot arm  48  having a second pivot pad  49 . The pivot arms  46 ,  48  snap and lock into the pivot posts  65 ,  66  extending from the jet pump tube  62  of the fuel pump module  20 . The first pivot arm  46  and the second pivot arm  48  pivot upon the pivot posts  65 ,  66  to permit the opening and closing of the check valve  67  formed by the counter-balanced inlet door  40  and the jet pump tube sealing surface  60 . With reference to  FIG. 8 , the door seal  54  moves away from the sealing surface  60  when the door opens. This is caused by the rotation of the inlet door  40  pivot arms  46 ,  48  when the arms rotate within the pivot posts  65 ,  66 .  
         [0030]      FIG. 6  depicts the counter-balanced inlet door  40  for a fuel pump module  20  check valve  67 , according to the teachings of a second embodiment, which will now be described. The difference between the inlet door  40  of the first embodiment of  FIG. 5  and the inlet door  40  of the second embodiment of  FIG. 6 , is in the respective door portions,  52  and  52   a . In  FIG. 6 , the door portion  52   a  is circular, while in  FIG. 5 , the door portion  52  has straight edges in its periphery. Depending upon the operative workings of the check valve  67 , the straight edges of the door portion  52  may be necessary to provide clearance from other parts of the check valve  67 .  
         [0031]     Before the operative workings of the embodiments is described, additional components related to the operation of the check valve  67  will be described. The fuel pump module  20  also has a jet pump  64  which pumps the liquid fuel of the fuel module  20  through the jet pump tube  62  and into the door portion  52  when the engine  12  is running or at least when the fuel pump module  20  is energized. When the fuel pump module is not energized, the fuel rises in the jet pump tube  62 , causing a resulting force of the pressure against the door seal  54  and door portion  52 . This force causes the counter-balanced inlet door  40  arms  46 ,  48  to pivot upon the pivot posts  65 ,  66 , open the inlet door  40  ( FIG. 8 ), and permit liquid fuel to flow into the jet pump tube  62  from the reservoir  22 .  
         [0032]     Now, a more detailed description of the operative workings of the counter-balanced inlet door  40  of the fuel pump module check valve  67  will be provided. Normally, when a vehicle fuel tank  30  possesses enough fuel to completely submerge the fuel pump module  20 , or at least engulf the jet pump tube  62 , the fuel easily flows from the fuel tank  30  into the fuel pump module  20  via the open inlet door  40  of the jet pump tube  62 , in order to provide fuel to the fuel pump module  20  and subsequently, to the engine  12  via fuel line  14 . This flowing of fuel is made possible because the counter-balanced inlet door  40  opens due to the force caused by the jet pump  64  forcing a stream of fuel  63  against the inside surface of the door portion  52  and door seal  54 . This is the normal operation when the engine is running; however, the embodiments of the present invention are capable of opening the check valve  67  when the engine is not running, that is, in order to get fuel into the jet pump tube  62 , when just a small amount of fuel is poured into an empty fuel tank  30  in order to re-start the vehicle engine  12 .  
         [0033]     An example of how the teachings of the present invention may be employed will now be explained. When a driver drives his car to the point that it runs out of fuel, he or she will normally pull over to the shoulder of the road on which the car is being driven. At this point, the driver will then need to put fuel into the fuel tank to restart the engine. This may mean that as little as one gallon of fuel will be carried from a filling station to be placed into the vehicle.  
         [0034]     When the vehicle runs out of fuel, it is a result of all of the fuel in the fuel tank  30  and the fuel pump module  20 , including the jet pump tube  62 , from being pumped to the engine  12 . This means that since the jet pump  64  has stopped pumping fuel through the jet pump tube  62 , which normally causes the inlet door  40  to remain open, the inlet door  40  closes. In order for the gallon of fuel, which the vehicle operator places into the fuel tank, to gain entry into the jet pump tube  62 , the fuel level must be at a level capable of creating a force against the interior of the inlet door  40  large enough to cause a moment large enough to rotate, and hence lift, the inlet door  40  of the jet pump tube  62 . This is a rotation of the inlet door  40  in  FIGS. 7 and 8 . When the inlet door  40  opens, causing fuel to enter the jet pump tube  62 , the jet pump  64  will eventually begin to pump again, and thus, keep the inlet door  40  open. The inlet door  40  will remain open as long as there is fuel for the jet pump  64  to pump. The reason the inlet door  40  is permitted to close is to retain the liquid fuel within the jet pump tube  62  to restart the engine after the engine is shut off. That is, the fuel pump module  20  and engine  12  rely on the fuel in the jet pump tube  62  for restarting, so the inlet door  40  closes to retain this fuel.  
         [0035]     As depicted in  FIG. 4 , the angle X of the shoulder plays a role in determining how much fuel is necessary to be put into the tank in order to open the jet pump tube  62  inlet door  40 . This was taken into consideration in the present embodiment. For instance, the teachings of the present embodiment take into consideration the fact that the greater the slope of the road shoulder, the greater the volume of fuel that must be poured into the fuel tank so that the fuel will rise high enough to not only make contact with the inlet door  40 , but place enough hydrostatic force against it to cause it to rotate and open. For the present preferred embodiment, the angle X is 4 degrees, which is a 7 percent slope.  
         [0036]     When the level of fuel in the fuel tank is so low, or empty, that starting the engine is not possible, the fuel level must be brought above the level “Y” indicated in  FIG. 7 . At the level “Y” the inlet door  40  will not yet open; however, at the level “Z” noted in  FIG. 8 , the inlet door  40  opens due to the hydrostatic force placed on the door by the pressure of the fuel when the vehicle is refueled with a gallon of fuel, or more, at the side of a road. That is, the level of fuel from one gallon of fuel is high enough to cause a great enough pressure, resulting force and moment about the pivot point of pivot arms  46 ,  48  to cause the inlet door  40  to open and fuel to enter the jet pump tube  62 . This opening is accomplished with the assistance of the counterweight  42  and the resulting moment about the pivot point of pivot arms  46 ,  48  of the inlet door  40 , since their moments act in the same direction.  
         [0037]     To the contrary, the opening of the inlet door is not possible with the prior art door of  FIGS. 10 and 11  under the same conditions. That is, after a vehicle has run out of fuel, and the level of fuel is brought to the level “Z” of  FIG. 8 , the inlet door of the prior art of  FIGS. 10 and 11  is not capable of opening by the hydrostatic force of the liquid fuel against the door portion of the inlet door. The level of fuel must be much higher than the level “Z” of  FIG. 8 . That is, the force against the door portion of the inlet door is not great enough to cause a large enough moment to open the inlet door until the level is much higher than the level “Z” of  FIG. 8  for the prior art door of  FIGS. 10 and 11 .  
         [0038]     Therefore, the counter-balanced inlet door  40  and the jet pump tube sealing surface  60  of the fuel pump module  20  form a check valve  67  that is a one-way valve that prevents fuel from exiting the jet pump tube  62  after the fuel level in the fuel tank  30  has dropped to a particular level, such as the height Y in  FIG. 7 . The reason the counter-balanced inlet door  40  closes when the fuel pump module  20  is de-energized, is to prevent fuel from flowing out of reservoir  22 . This permits fuel to remain in the module  20  at all times, even when the fuel pump module  20  is not operating and the fuel level is below level Z of  FIG. 8 . When the fuel pump module reservoir  22  is filled with fuel and the fuel pump module  20  within the fuel pump reservoir  22  is surrounded with fuel, the engine  12  can easily be restarted because there is a plentiful supply of fuel available to the fuel pump module  20 .  
         [0039]     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.