Abstract:
A fuel pump module includes a reservoir having a jet pump attached to the outer surface of the reservoir. The jet pump includes a pump body which is ultrasonically welded to the reservoir and a jet nozzle which extends from the pump body towards an inlet to the reservoir. An alignment device or the jet pump engages an alignment device on the reservoir to ensure that the jet nozzle will be in accurate alignment with the inlet of the reservoir.

Description:
FIELD OF THE INVENTION 
     The present invention relates to fuel pump modules for use in an automotive fuel system. More particularly, the present invention relates to an improved fuel pump module which improves the alignment between the jet pump nozzle and the throat. 
     BACKGROUND OF THE INVENTION 
     In recent years, an increasing number of automobiles have included fuel systems wherein the fuel pump for the system is incorporated within the fuel tank of the automobile. In such systems, the fuel pump is typically located within a canister or reservoir in the fuel tank and the reservoir is overfilled with fuel supplied from a fuel return line which returns an oversupply of fuel from the automobile&#39;s engine (a return system) or from the excess fuel from a pressure regulator (returnless system). As the fuel returns from the engine through the return line, it is typically routed through a venturi orifice or jet pump and into an inlet passage leading into the canister or reservoir. The inlet passage is submerged in fuel within the fuel tank and the fuel exiting the venturi or jet pump creates a pressure drop in the area of the inlet passage such that additional fuel from the fuel tank is conveyed into the canister or reservoir along with the fuel jetted from the venturi orifice or jet pump into the inlet passage. 
     The venturis or jet pumps in use today are generally formed as fixed nozzles wherein the orifice size is optimized for the anticipated use. When the barrel of the jet pump nozzle is extended in length to facilitate the installation of the jet pump to the fuel tank and/or optimize the position of the throat opening, the increase in length will exaggerate the angular deviation located at the outlet of the nozzle. This angular deviation is caused by the designed dimensional tolerances, the manufacturing tolerances and the manufacturing procedures. Any misalignment of the jet pump nozzle and the throat will adversely affect the performance of the pump by potentially causing a severe loss in suction performance of the jet pump, ultimately leading to poor driveability of the vehicle. 
     The continued development for the jet pumps for the fuel systems has been directed to jet pump designs and jet pump manufacturing procedures which reduce and/or eliminate misalignment between the jet pump nozzle and the throat, especially when an extended length jet pump nozzle is being utilized. 
     SUMMARY OF THE INVENTION 
     The present invention provides the art with an improved jet pump nozzle design which incorporates an alignment device which minimizes misalignment between the jet pump nozzle and the throat. In one embodiment, a tapered elliptical slide engages a groove to properly align the jet pump nozzle with the throat prior to ultrasonic welding of the jet pump to the fuel tank. In another embodiment of the present invention, a hook formed on the jet pump nozzle is designed to engage a slot formed on the tank to align the jet pump nozzle with the throat prior to the ultrasonic welding of the two components. In yet another embodiment of the present invention, a tapered peg formed on the tank is designed to engage a slot formed on the jet pump prior of the ultrasonic welding of the two components. In still yet another embodiment of the present invention non-circular ultrasonic welding grooves are formed on the two components. The mating of the two non-circular ultrasonic weld grooves prior to ultrasonic welding of the components ensures the alignment between the jet pump nozzle and the throat. 
     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 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
     FIG. 1 is a schematic representation of an automotive engine and fuel system which utilizes a unique jet pump in accordance with an embodiment of the present invention; 
     FIG. 2 is an exploded perspective view of the reservoir assembly shown in FIG. 1; 
     FIG. 3 is an enlarged cross-sectional view of the jet pump illustrated in FIG. 1; 
     FIG. 4 is a perspective view of the alignment system for the jet nozzle of the jet pump illustrated in FIGS. 1 and 2; 
     FIG. 5 is a perspective view of an alignment system for the jet nozzle of the jet pump in accordance with another embodiment of the present invention; 
     FIG. 6 is a perspective view of an alignment system for the jet nozzle of the jet pump in accordance with another embodiment of the present invention; 
     FIG. 7 is a perspective view of an alignment system for the jet nozzle of the jet pump in accordance with another embodiment of the present invention; and 
     FIG. 8 is a perspective view of an alignment system for the jet nozzle of the jet pump in accordance with another embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     Referring now to the drawings in which like reference numerals designate like or corresponding parts throughout the several views, there is shown in FIG. 1 an automotive engine and fuel system which incorporates a unique jet pump in accordance with the present invention and which is designated generally by the reference numeral  10 . Automotive engine and fuel system  10  comprises an internal combustion engine  12  of a motor vehicle (not shown) which is supplied with fuel from a fuel tank  14 . The fuel is supplied through a feeding conduit  16  which leads from fuel tank  14  to internal combustion engine  12 . Feeding conduit  16  provides a continuous supply of high pressure fuel to internal combustion engine  12  and feeding conduit  16  is the only fuel line extending between fuel tank  14  and internal combustion engine  12 . 
     Referring to FIG. 2, a fuel pump module which includes a canister or reservoir  18  is disposed within fuel tank  14 . Fuel is pumped from reservoir  18  by a fuel pump  20  through a filter  22  and into feeding conduit  16 . In order to maintain a specified pressure of fuel being supplied by fuel pump  20 , a pressure regulator assembly  24  is disposed within reservoir  18  and is also in communication with feeding conduit  16 . Pressure regulator assembly  24  opens at a specified fluid pressure to return excess fuel back to the reservoir  18  via the jet pump  30 . Fuel pump  20  receives fuel through a suction filter  26  and pumps this fuel through filter  22  and into feeding conduit  16 . After reservoir  18  is positioned within fuel tank  14 , a flange  28  is secured to fuel tank  14  to seal fuel tank  14 . A plurality of struts and biasing springs maintain the position of reservoir  18  within fuel tank  14 . A jet pump  30  is disposed within fuel tank  14  and it is connected to pressure regulator assembly  24 . During the operation of internal combustion engine  12 , fuel pump  20  pumps fuel from reservoir  18  in fuel tank  14  through filter  22 , through feeding conduit  16  and to internal combustion engine  12 . Internal combustion engine  12  utilizes fuel supplied from feeding conduit  16  which is kept at a specified pressure by pressure regulator assembly  24 . Excess fuel pumped by fuel pump  20  is returned to reservoir  18  through pressure regulator assembly  24  and jet pump  30 . Jet pump  30  is connected to pressure regulator assembly  24  and jet pump  30  pumps fuel from pressure regulator assembly  24  into canister or reservoir  18 . Jet pump  30  creates a suction pressure which draws fuel from fuel tank  14  and this fuel along with the excess fuel is pumped into reservoir  18 . The pumping of fuel by jet pump  30  from fuel tank  14  into reservoir  18  ensures that reservoir  18  is always sufficiently filled. A check valve maintains the fuel within reservoir  18  when fuel pump  20  is not operating. Jet pump  30  is driven by the fuel which flows through pressure regulator assembly  24  in a manner similar to that known in the art for jet pumps attached to return lines. 
     Jet pump  30  is illustrated in FIG. 3 partially in cross-section in an enlarged scale. Jet pump  30  comprises a jet nozzle  32 , a mixing pipe or throat  34  which is alignment with jet nozzle  32  and a suction opening  36  located between jet nozzle  32  and mixing pipe or throat  34 . Jet nozzle  32  is attached to a pump body  38  which is connected at the inlet side to the outlet of pressure regulator assembly  24 . Pump body  38  is open to jet nozzle  32  which is in turn opened at its opposite end adjacent mixing pipe or throat  34 . Mixing pipe or throat  34  is a formed part of reservoir  18  or mixing pipe or throat  34  is inserted into reservoir  18  near its bottom so that mixing pipe or throat  34  provides a connection between the interior of fuel tank  14  and the interior of canister or reservoir  18 . 
     In the embodiment shown in FIGS. 3 and 4, jet nozzle  32  is arranged a specified distance from the opening of mixing pipe or throat  34  in alignment with throat  34 . Suction opening  36  is formed by the free space remaining between jet nozzle  32  and mixing pipe or throat  34 . In order to ensure the proper alignment between jet nozzle  32  and throat  34 , an alignment mechanism in the form of a tapered elliptical slide  40  (a first alignment device) is formed on the end of the extended barrel of jet nozzle  32 . Tapered elliptical slide  40  is designed to engage a slot  42  (a second alignment device) formed by one of the walls of reservoir  18  in fuel tank  14 . Once tapered elliptical slide  40  has been inserted into slot  42 , pump body  38  of jet pump  30  is ultrasonically welded to reservoir  18  at location  44  on fuel tank  14  and at location  46  on pump body  38  of jet pump  30 . One or both of reservoir  18  and pump body  38  of jet pump  30  include formed ultrasonic circular welding grooves  48  to facilitate the ultrasonic welding of pump body  38  of jet pump  30  to reservoir  18 . 
     During the operation of internal combustion engine  12 , the fuel which flows through pressure regulator assembly  24  exits as a jet with high speed from jet nozzle  32 . The fuel jet receives, in the region of suction opening  36 , fuel from within fuel tank  14  and pumps it through mixing pipe or throat  34  along with the jetted fuel so that fuel is fed from fuel tank  14  through mixing pipe or throat  34  opening the check valve and filling the canister or reservoir  18 . The fuel that is withdrawn from fuel tank  14  together with the fuel exiting jet nozzle  32  is supplied to the canister or reservoir  18 . During the operation of internal combustion engine  12 , the constantly operating jet pump  30  guarantees that, independently from the fuel level in fuel tank  14 , reservoir  18  is always completely filled with fuel and thereby the fuel to internal combustion engine  12  operates without distortion up to a minimum filling level. The engagement between elliptical slide  40  with slot  42  prior to and during the ultrasonic welding of jet pump  30  to reservoir  18  ensures that jet nozzle  32  will be properly aligned with throat  34  to provide the highest pump efficiency for jet pump  30 . During welding, jet pump  30  is inverted. This causes the extended barrel of jet nozzle  32  to tilt or rotate somewhat around circular grooves  48  due to its weight. This tilting could cause misalignment with throat  34 . The engagement of tapered elliptical slide  40  with slot  42  prevents the tilting of the extended barrel of jet nozzle  32 . As jet pump  30  is welded to reservoir  18 , the taper of tapered elliptical slide  40  causes the extended barrel of jet nozzle  32  to center itself during the welding process to further reduce the possibility of misalignment. The elliptical design of tapered elliptical slide  40  enables the operator to slide the extended barrel of jet nozzle  32  into position along the longer axis of the ellipse with ease. 
     Referring now to FIG. 5, a reservoir  118  and a jet pump  130  in accordance with another embodiment of the present invention is illustrated. Jet pump  130  comprises a jet nozzle  132 , a mixing pipe or throat  134  which is in alignment with jet nozzle  132  and a suction opening  136  located between jet nozzle  132  and mixing pipe or throat  134 . The function and operation of reservoir  118  and jet pump  130  is the same as detailed above for reservoir  18  and jet pump  30 . The difference between jet pump  130  and jet pump  30  is in the alignment mechanism. Tapered elliptical slide  40  formed on jet nozzle  32  is replaced by a hook  140  formed on jet nozzle  132  and slot  42  formed on reservoir  18  is replaced by a slot  142  formed on reservoir  118 . The engagement between hook  140  and slot  142  ensures the alignment of jet nozzle  132  with throat  134  prior to and during the ultrasonic welding of jet pump  130  to reservoir  118 . Jet pump  130  is ultrasonic welded to reservoir  118  at locations  44  and  46  using welding grooves  48  the same as jet pump  30 . Hook  140  can easily be inserted into slot  142  by the operator to properly position jet pump  130  prior to the welding process. This will ensure that jet nozzle  132  does not deviate beyond functional limits during the welding process. The hook also includes a taper, thus achieving the self-centering as detailed above. 
     Referring now to FIG. 6, a reservoir  218  and a jet pump  230  in accordance with another embodiment of the present invention is illustrated. Jet pump  230  comprises a jet nozzle  232 , mixing pipe or throat  134  which is in alignment with jet nozzle  232 , suction opening  136  located between jet nozzle  232  and mixing pipe or throat  134  and a pump body  238 . The function and operation of reservoir  118  and jet pump  230  is the same as detailed above for reservoir  18  and jet pump  30 . The difference between jet pump  230  and jet pump  30  is in the alignment mechanism. Tapered elliptical slide  40  formed on jet nozzle  32  is replaced by a slot  240  formed on pump body  238  and slot  42  formed on reservoir  18  is replaced by a tapered peg  242  formed on reservoir  218 . The engagement between tapered peg  242  and slot  240  ensures the alignment of jet nozzle  232  with throat  134  prior to and during the ultrasonic welding of jet pump  230  to reservoir  218 . Jet pump  230  is ultrasonically welded to reservoir  218  at locations  44  and  46  using welding grooves  48  the same as jet pump  30 . The advantages of this embodiment is tapered peg  242  and slot  240  do not interfere with suction opening  136  of jet pump  230  and that this design can be used irrespective of the length of the extended barrel of jet nozzle  232 . In the applications that have a greater demand for suction performance, the area of suction opening  136  becomes a major consideration. 
     Referring now to FIG. 7, a reservoir  318  and a jet pump  330  in accordance with another embodiment of the present invention is illustrated. Jet pump  330  comprises a jet nozzle  332 , mixing pipe or throat  134  which is in alignment with jet nozzle  332  and suction opening  136  located between jet nozzle  332  and mixing pipe or throat  134 . The function and operation of reservoir  318  and jet pump  330  is the same as detailed above for reservoir  18  and jet pump  30 . The difference between jet pump  330  and jet pump  30  is in the alignment mechanism. Tapered elliptical slide  40  formed on jet nozzle  32  is replaced by a tapered elliptical slide  340  formed on jet nozzle  332  and slot  42  formed on fuel tank  14  is replaced by a slot  342  formed on reservoir  318 . The engagement between tapered elliptical slide  340  and slot  342  ensures the alignment of jet nozzle  332  with throat  134  prior to and during the ultrasonic welding of jet pump  330  to reservoir  318 . Jet pump  330  is ultrasonically welded to reservoir  318  at locations  44  and  46  using welding grooves  48  the same as jet pump  30 . This embodiment is similar to the embodiment illustrated in FIG. 4 with the difference being the location of tapered elliptical slide  340  in relation to the location of tapered elliptical slide  40  and the corresponding location of slot  342  in relation to the location of slot  42  which are closer to pump body  38 . The advantages of this embodiment is that there is no potential suction flow restriction of suction opening  136 . 
     Referring now to FIG. 8, a reservoir  418  and a jet pump  430  in accordance with another embodiment of the present invention is illustrated. Jet pump  430  comprises a jet nozzle  432 , mixing pipe or throat  134  which is in alignment with jet nozzle  432  and suction opening  136  located between jet nozzle  432  and mixing pipe or throat  134  and a pump body  438 . The function and operation of reservoir  418  and jet pump  430  is the same as detailed above for reservoir  18  and jet pump  30 . The difference between jet pump  330  and jet pump  30  is in the alignment mechanism. Tapered elliptical slide  40  formed on jet nozzle  32  and slot  42  formed on reservoir  18  have been eliminated. Instead of tapered elliptical slide  40  and slot  42 , circular welding grooves  48  on pump body  38  of jet pump  30  are replaced by non-circular welding grooves  448  on reservoir  418  and non-circular grooves  448  on pump body  438  of jet pump  430 . Non-circular welding grooves  448  are preferably elliptical in shape in order to avoid any corners that may disrupt a hermetic seal during the ultrasonic welding operation. The mating of the two elliptical designs restricts the amount of rotational deviation possible during the ultrasonic welding operation. Choosing the ratio of the major axis to the minor axis of the ellipse close to unity helps to eliminate the limitations of a circular weld line while retaining the performance of the ultrasonic weld. 
     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.