Abstract:
A fuel sump with a draw tube on the inside of the fuel tank to maximize the fuel available to the engine eliminate an exterior fuel line that would normally be exterior to the fuel tank attached to the fuel sump.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of prior filed, co-pending application Ser. No. 61/842,661, filed Jul. 3, 2013, entitled FUEL SUMP AND WITHDRAWAL APPARATUS. 
     
    
     FIELD 
       [0002]    This invention relates to automotive fuel tank sump systems. More specifically, it relates to a fuel sump in combination with a draw tube to minimize ingesting of air with the fuel and maximize the available fuel. 
       BACKGROUND 
       [0003]    Diesel fuel engines are notoriously sensitive to entrained air in their fuel lines. Due to how a diesel engine operates, first compressing air in the combustion chamber and then introducing fuel, an elevated level of entrained air in diesel engine supply fuel can have a dramatic impact on engine performance. Air in the fuel line can damage fuel injectors and throw off engine timing. This can result in loss of horsepower, loss of mileage per gallon, and overall inconsistent engine performance. Therefore, to maximize diesel engine performance, the amount of air entrained in the fuel being supplied to the engine should be minimized. 
         [0004]    Air bubbles form in diesel fuel lines for a number of reasons, the most common of which is agitation of the fuel while the vehicle is in motion. Diesel fuel dispensed into a vehicle from a fuel pump likely has air present in it, though the air is generally in the form of microscopic bubbles that have not yet materialized into larger more damaging bubbles. Air at the molecular level typically forms into the larger more damaging visible bubbles when the diesel fuel is agitated, such as in a vehicle&#39;s fuel tank while the vehicle is in motion. 
         [0005]    The desire to keep entrained air quantities low in fuel being supplied to engines has led to the creation and production of high performance fuel air separation systems. Such air separation systems are commonly installed on vehicles or other machines where the associated engine is intended to perform at a high level. The systems serve as a strainer for the fuel before it reaches the engine, removing much of the sediment and entrained air before the fuel is sent to the fuel injectors and combustion chamber. These systems generally comprise a fuel pump, an air separator and, in high flow systems, a vertical draw tube for drawing the fuel from the fuel tank. 
         [0006]    A common problem with the draw tube systems is that they perform poorly when the fuel tank is low. Problems generally occur when the tank is one quarter full or less. This is due in large part to the fuel in the tank shifting when the vehicle is in motion and consequently moving away from the intake draw tube. This may result in an inordinate amount of air being sucked into the fuel system, which results in a much larger quantity of air in the fuel supply system than the air separator system can remove. Consequently, even with an air separator system installed, when a draw tube configuration is used and the fuel drops near or below one quarter tank, engine and fuel injector problems still occur. 
         [0007]    Fuel tank sump systems can be used in lieu of the draw tube configuration to combat this low fuel level issue. These sump systems generally comprise a fuel sump or container attached to the bottom of a vehicle fuel tank, and a fuel draw tube drawing fuel from the sump. The fuel draw tube typically attaches to the side of the sump on the outside of the fuel tank and serves as the sole fuel withdrawal mechanism for the entire fuel tank. Because the tube is attached to the side of the sump, and the sump is the lowest point in the fuel system, the chance that air will be pulled into the fuel supply system, even at low tank levels, is minimized. The nature of the sump and its associated draw tube is that the inlet of the tube is always flooded as long as there is fuel in the sump. 
         [0008]    A problem with this configuration is that the side draw tube is routed along the exterior bottom of the vehicle&#39;s fuel tank and is generally fully exposed and unprotected. This tube is often made of flexible rubber hose to make installation easier. Any article that the vehicle drives over could potentially make contact with the exposed fuel draw tube and damage it, or knock it off. This situation could occur when driving over road debris or in off-road conditions such as mounds or ditch embankments, undercarriage car washes, and even vandalism. Therefore, a system is needed that has the functionality of the fuel sump system without the weakness of an exposed fuel line below the vehicle fuel tank. 
       SUMMARY 
       [0009]    The present invention includes a fuel sump and draw tube on the inside of the fuel tank to maximize the fuel available to the engine and minimize the likelihood of breaking a fuel line that would normally be exterior to the fuel tank attached to the fuel sump. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a perspective view of a sump withdrawal apparatus installed in a fuel tank. 
           [0011]      FIG. 2  is an exploded perspective view of a sump withdrawal apparatus installed in a fuel tank. 
           [0012]      FIG. 3  is a partially exploded bottom perspective of a sump withdrawal apparatus. 
           [0013]      FIG. 4  is a cross sectional view of the sump withdrawal apparatus taken along line  4  of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof 
         [0015]    Certain terminology will be used in the following description for convenience in reference only and will not be limiting. For example, the words “upwardly,” “downwardly,” “rightwardly,” and “leftwardly” will refer to the installed position of the item to which the reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the embodiment being described and designated parts thereof Said terminology will include the words specifically mentioned, derivatives thereof and words of a similar import. 
         [0016]    Referring to the drawings in more detail, reference numeral  10  refers to a fuel sump withdrawal apparatus attached to a fuel tank  12  and integrally communicating with the interior of the tank via hole  14  in the floor  16  of the tank. The fuel sump withdrawal apparatus  10  includes a sump  18 , a support bracket  20 , and a fuel draw tube  22 . Fuel sump withdrawal apparatus  10  is typically connected to the vehicle fuel supply system via flexible tube  24 . Flexible tube  24  then connects to a fuel distribution tee  26 . The remaining portion of the vehicle fuel distribution system also connects to fuel distribution tee  26 . 
         [0017]    Sump  18  includes a holding vessel  28  with a sidewall  30  and a floor  32  forming an interior cavity  34  for holding fuel. One configuration of the sidewall  28  and floor  32  is a cylindrical shape with sidewall  30  having a curvature and floor  32  having a circular shape. Sidewall  30  extends upwardly from floor  32  to form interior cavity  34 . Floor  32  slopes downwardly toward its center. 
         [0018]    Sump  18  also has an annular clamping flange  36  at the top of holding vessel  28 . Clamping flange  36  includes a planar top surface  38  and an overhang  42  projecting outward from and encircling the top of holding vessel  28 . A plurality of fastener holes  40  through clamping flange  36  are located midway between the outer circumferential edge  42  and inner circumferential edge  44  of flange  36 , and the fastener holes  40  are equally spaced radially about the entirety of the flange. 
         [0019]    Sump  18  further includes a lip  46  at the top of the holding vessel  28  that is adjacent to and rising above the inner circumferential edge  44  of clamping flange  36 . Lip  46  aids in installation and alignment of sump  18  within mounting hole  14  in fuel tank  12 . When sump  18  is installed, lip  46  is inserted into tank hole  14  such that the lip  46  is immediately adjacent the rim  48  of the tank hole  14 . Circumferentially surrounding tank hole  14  is a plurality of mounting holes  50  through tank floor  16 , sized so that threaded fasteners  52  can move freely through the mounting holes. 
         [0020]    Sump  18  is attached to fuel tank  12  by first placing threaded fasteners  52  through fastener holes  40 , then through mounting holes  50 , and then threadably engaging clamping band  54  on the interior of tank  12 . Clamping band  54  is an arcuate band, which may have an arc of more, less, or equal to one hundred eighty degrees, and the band comprises a plurality of threaded holes  56  for receiving threaded fasteners  52 . Clamping band  54  has a plurality of shallow channels  58  arranged transversely across the underside of clamping band  54  in a radial fashion. The shallow channels  58  allow fuel to pass from the outer periphery of the clamping band  54  to the inner periphery and thus into sump  18  when the band  54  is installed. This minimizes the potential that the clamping band  54  will prohibit fuel from reaching the sump  18 . 
         [0021]    Clamping band  54  is installed inside fuel tank  12 , and when threaded fasteners  52  engage threaded holes  56 , sump  18  is secured to the exterior of fuel tank  12  with floor  16  being clamped between clamping band  54  and sump  18 . It is foreseen that two or more clamping bands  54  may be used to secure sump  18  to the tank  12  depending on the size of the sump and the configuration of the fuel tank. A rubber O-ring or gasket material may be installed between the flange  36  and the fuel tank bottom  16  to prevent fuel leaks. 
         [0022]    Clamping band  54  also has a threaded aperture  60  for mounting support bracket  20  to clamping band  54  inside tank  12 . Support bracket  20  includes a mounting end  62  and a support end  64 . Mounting end  62  has an aperture  66  for receiving a fastener  68  therethrough. The fastener  68  threadably engages the threaded aperture  60  to secure the support arm  20  to the clamping band  54 . Mounting end  62  has an inset mounting surface  70  that rests atop clamping band  54  on the band&#39;s upper surface  72 . Inset mounting surface  70  allows support arm  20  to partially envelop clamping band  54 , thus creating a stop against band  54  to prevent support arm  20  from rotating about the fastener  68 . 
         [0023]    Support end  64  is the distal end of support arm  20  and projects radially inwardly from the clamping band  54  such that support end  64  is located above sump  18  proximate the axial center of sump  18 . Support end  64  comprises an open cylinder  74  for holding fuel draw tube  22 . Open cylinder  74  includes one or more set screws  76  for securing draw tube  22  at the desired position and height above the bottom  78  of the sump  18 . 
         [0024]    Fuel draw tube  22  is inserted into open cylinder  74  and positioned to the desired height and set screw  76  is tightened to engage the side of tube  22  to keep it in place. The open end  80  of tube  22  is generally located approximately one-eighth inch above bottom  78  of the holding vessel  28  proximate the center of the bottom  78 . 
         [0025]    It is to be understood that while certain forms of this invention have been illustrated and described, it is not limited thereto, except in so far as such limitations are included in the following claims and allowable equivalents thereof.