Patent Publication Number: US-10309424-B1

Title: Vehicle fuel pump module including improved jet pump assembly

Description:
FIELD OF THE INVENTION 
     The present invention relates to vehicle fuel systems, and more particularly to vehicle fuel systems including jet pump assemblies. 
     BACKGROUND OF THE INVENTION 
     The use of bifurcated fuel tanks, also commonly referred to as saddle tanks, in conjunction with fuel delivery systems having a single fuel pump is known. In such systems, a reservoir surrounds the fuel pump and is constantly filled to ensure that a steady supply of fuel is available to the pump at all times. Normally, fuel is drawn into the fuel pump from the bifurcated tank portion housing the fuel pump, but if the fuel level is low or vehicle maneuvering is such that the fuel pump inlet cannot draw fuel, the fuel pump instantly draws fuel from the reservoir. A jet pump is typically used to draw fuel from the opposing bifurcated portion of the tank through a crossover line and into the reservoir. Fuel typically overflows the reservoir and excess fuel fills the bifurcated tank portion housing the fuel pump. This ensures that fuel is available to the fuel pump regardless of the level of fuel in either of the bifurcated tank portions. 
     Some fuel systems include a filtering choke in the fuel supply line that supplies the jet pump. The filtering choke functions to provide a pressure drop by restricting flow through an orifice. In addition, the filtering choke functions to filter the fuel in the fuel supply line to prevent debris from clogging the choke orifice or other orifices downstream. However, manufacture of a filtering choke via a molding operation is challenging since the orifices that form the choke and filter are often at a lower limit of sizes that can be formed in a molding operation. 
     SUMMARY OF THE INVENTION 
     In some aspects, a vehicle fuel pump module includes a reservoir configured to be disposed in a fuel tank of the vehicle, and a jet pump assembly that is disposed in the reservoir. The jet pump assembly comprises a fluid supply conduit, an internal chamber, a primary jet pump, and a passageway. The primary jet pump includes a primary nozzle and a primary mixing tube. The primary nozzle includes a primary nozzle inlet that communicates with the fuel supply conduit and a tapered primary nozzle outlet. The primary mixing tube receives fluid discharged from the primary nozzle outlet and is in fluid communication with the internal chamber. The passageway extends between the fuel supply conduit and the primary nozzle inlet. The passageway is parallel to a direction of fluid flow through the fuel supply conduit and perpendicular to a longitudinal axis of the primary nozzle. The passageway includes a jet pump choke that is configured to provide a reduced pressure at the primary nozzle inlet relative to a pressure in the fluid supply conduit. The jet pump choke includes a choke ball disposed in the passageway, and a choke slot that is formed in the inner surface of the passageway. The choke slot extends along a direction that is perpendicular to the longitudinal axis of the primary nozzle. The choke ball is dimensioned to be press fit within the passageway such that the choke ball is fixed within the passageway and fully obstructs the passageway. In addition, a fluid path is defined between the choke ball and surfaces of the choke slot, the fluid path providing fluid communication between the fuel supply conduit and the primary nozzle inlet. 
     In some embodiments, a first area is defined by a cross section of the fluid path that is perpendicular to a direction of fluid flow through the fluid path, and a second area is defined by a cross section of the passageway that is perpendicular to a direction of fluid flow through the passageway, and the first area is less than the second area. 
     In some embodiments, the jet pump assembly comprises a secondary jet pump that includes a secondary nozzle and a secondary mixing tube. The secondary nozzle includes a secondary nozzle inlet that communicates with the fuel supply conduit and a tapered secondary nozzle outlet. The secondary mixing tube is configured to receive fluid that has been discharged from the secondary nozzle, and the jet pump choke is disposed between the secondary nozzle inlet and the primary nozzle inlet. 
     In some embodiments, the secondary mixing tube is configured to receive a first portion of fluid that has been discharged from the secondary nozzle outlet and receive a second portion of fluid that is drawn from a portion of a fuel tank of the vehicle, and discharge the first and second portions of fluid to the reservoir. 
     In some embodiments, the secondary mixing tube is configured to discharge fluid received from the secondary nozzle to the reservoir via a standpipe having an outlet that resides at location corresponding to an open end of the reservoir. 
     In some embodiments, the vehicle fuel pump module includes a jet pump feed tube that is connected to the jet pump assembly. The jet pump feed tube includes a feed tube inlet, a feed tube outlet that is connected to and communicates with the fluid supply conduit, and a feed tube passageway that extends between the feed tube inlet and the feed tube outlet. A filtering choke is disposed within the feed tube passageway at a location between the feed tube inlet and the feed tube outlet. The filtering choke includes a choke housing that includes a fluid inlet, a fluid outlet, a choke housing passageway that extends between the fluid inlet and the fluid outlet, a choke housing longitudinal axis that extends between the fluid inlet and the fluid outlet, and a filter slot that is formed in a surface of the choke housing passageway. The filter slot extends in parallel to the choke housing longitudinal axis, and a filter ball is disposed in the choke housing passageway. The filter ball is dimensioned to be press fit within the choke housing passageway at a location corresponding to the location of the filter slot such that the filter ball is fixed within the choke housing passageway and abuts the filter slot. In addition, a fluid path is defined between the filter ball and surfaces of the filter slot, the fluid path providing fluid communication between the feed tube inlet and the feed tube outlet. 
     In some embodiments, the filtering choke is formed by a molding process in which slots are formed in a fluid passageway upstream relative to an orifice plate that serves as a choke orifice. The slots extend in the direction of fluid flow through the passageway, and a ball is press fit into the passageway at a location corresponding to the slots. As a result, the ball is fixed within the passageway and fully obstructs and closes the passageway. In addition, fluid within the passageway is diverted through the slots, which provide a fluid path around the ball. The slots are dimensioned to be the same size or smaller than the choke orifice, and thus the ball and slots cooperate to provide a filtering function that prevents debris from clogging the choke orifice or other orifices downstream. In particular, the cross sectional dimensions of the slot determine the filtration efficiency of the filtering choke. In the filtering choke, the fluid flow direction is unchanged, whereby the filtering choke can be installed inline in an existing flow channel. 
     In some aspects, a vehicle fuel pump module includes a reservoir configured to be disposed in a fuel tank of the vehicle; and a jet pump assembly that is disposed in the reservoir. The jet pump assembly comprises a fluid supply conduit, an internal chamber, a primary jet pump, and a secondary jet pump. The primary jet pump includes a primary nozzle and a primary mixing tube. The primary nozzle includes a primary nozzle inlet that communicates with the fuel supply conduit and a tapered primary nozzle outlet. The primary mixing tube receives fluid discharged from the primary nozzle outlet and is in fluid communication with the internal chamber. The secondary jet pump includes a secondary nozzle and a secondary mixing tube. The secondary nozzle includes a secondary nozzle inlet that communicates with the fuel supply conduit and a tapered secondary nozzle outlet. The secondary mixing tube is configured to receive fluid that has been discharged from the secondary nozzle. The jet pump assembly also includes a jet pump choke that is disposed in the fuel supply conduit at a location between the secondary nozzle inlet and the primary nozzle inlet. The jet pump choke is configured to provide a reduced pressure at the primary nozzle inlet relative to a pressure in at the secondary nozzle inlet, and includes a choke housing that defines a passageway, a choke ball disposed in the passageway, and a choke slot that is formed in the inner surface of the passageway. The choke slot extends along a direction that is perpendicular to the longitudinal axis of the primary nozzle. The choke ball is dimensioned to be press fit within the passageway such that the choke ball is fixed within the passageway and fully obstructs the passageway, and a fluid path is defined between the choke ball and surfaces of the choke slot, the fluid path providing fluid communication between the fuel supply conduit and the primary nozzle inlet. 
     The filtering choke formed of a ball fixed within a slotted passageway is both easier and less expensive to manufacture and assemble than some conventional filtering chokes that are formed by overmolding a mesh filter to be disposed in the passageway upstream of the choke orifice. 
     In some embodiments, a choke is formed by a molding process in which a slot is formed in a fluid passageway. The slot extends in the direction of fluid flow through the passageway, and a ball is press fit into the passageway at a location corresponding to the slot. As a result, the ball is fixed within the passageway and fully obstructs and closes the passageway. In addition, fluid within the passageway is diverted through the slot, which provides a fluid path around the ball. The slot is shaped and/or dimensioned to provide a required pressure drop in the same way as does the aperture of an orifice plate. As a result, the ball and slot cooperate to provide a choke function that provides a predetermined pressure drop within the passageway. 
     Other features and aspects of the invention will become apparent upon consideration of the following detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a filter housing and jet pump assembly of a vehicle fuel pump module. 
         FIG. 2  is an exploded perspective view of the filter housing and jet pump assembly of  FIG. 1 . 
         FIG. 3  is a schematic diagram of a fuel system including the jet pump assembly of  FIG. 1 . 
         FIG. 4  is a schematic diagram of an alternative embodiment fuel system including the jet pump assembly of  FIG. 1 . 
         FIG. 5  is a perspective view of the jet pump assembly of  FIG. 1 . 
         FIG. 6  is a cross-sectional view of the jet pump assembly as seen along line  6 - 6  of  FIG. 5 . 
         FIG. 7  is a cross-sectional view of the filter housing as seen along line  7 - 7  of  FIG. 2 . 
         FIG. 8  is a detail view of a portion of the filter housing of  FIG. 7 . 
         FIG. 9  is a detail view of a portion of the jet pump assembly of  FIG. 6 . 
         FIG. 10  is a cross sectional perspective view of a portion of the jet pump assembly as seen along line  10 - 10  of  FIG. 9 . 
         FIG. 11  is a cross sectional plan view of a portion of the jet pump assembly as seen along line  10 - 10  of  FIG. 9 . 
         FIG. 12  is a perspective view of a filtering choke. 
         FIG. 13  is a cross-sectional view of the filtering choke as seen along line  13 - 13  of  FIG. 12 . 
         FIG. 14  is a cross-sectional view of the filtering choke as seen along line  14 - 14  of  FIG. 12 . 
     
    
    
     It is understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of having other embodiments and of being practiced or of being carried out in various ways. Also, it is understood that the phrases and terms used herein are for the purpose of description and should not be regarded as limiting. 
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1-3 , a vehicle fuel system  1  used to provide fuel to an internal combustion engine (not shown) includes a fuel pump module  2  that is disposed in a vehicle fuel tank, for example a saddle-style fuel tank  4 . The fuel pump module  2  includes a reservoir  8  that contains a fuel pump  12 , a fuel pump filter  10  supported in a filter housing  24 , a secondary filter  14 , a check valve  18 , a fuel pressure regulator  20  and a jet pump assembly  40 . The fuel pump module  2  is positioned on a primary side  6  of the saddle-style fuel tank  4 . As described in more detail below, the jet pump assembly  40  draws fuel from both the primary side  6  of the fuel tank and a secondary side  7  of the fuel tank  4  into the reservoir  8  to fill the reservoir  8  and substantially immerse the fuel pump  12  with fuel. This allows the fuel pump  12  to access a substantially continuous supply of fuel regardless of the level of fuel in the primary side  6  or the secondary side  7  of the fuel tank  4 . 
     Referring to  FIGS. 3, 5 and 6 , the jet pump assembly  40  includes a fuel supply conduit  41  and a primary jet pump  43  integrally formed as a single piece with the fuel supply conduit  41  and oriented substantially normal to the fuel supply conduit  41 . The primary jet pump  43  is in fluid communication with the fuel supply conduit  41  to receive pressurized fuel from the fuel supply conduit  41  during operation of the fuel pump  12 . As seen in  FIG. 3 , the fuel supply conduit  41  receives pressurized fuel directly from the output of the fuel pump  12  via a filtering choke  80  positioned upstream of the fuel supply conduit  41  to reduce the pressure of the pressurized fuel delivered to the fuel supply conduit  41 . As used herein, the terms “upstream” and “downstream” are used with reference to a direction of fluid flow through the respective device. The filtering choke  80  will be described in detail below. 
     Referring to  FIG. 4 , the jet pump assembly  40  may alternatively be configured within the fuel pump module such that the fuel supply conduit  41  receives “return” fuel from the fuel pressure regulator  20  to power the primary jet pump  43 . The fuel pump  12  is sized to deliver fuel to the engine at a maximum flow rate and pressure. The fuel pressure regulator  20  provides a regulated supply of fuel to the engine that is often less than the maximum flow rate and pressure that the fuel pump  12  is capable of providing. The fuel pressure regulator  20 , therefore, returns excess fuel that is not needed by the engine to the reservoir  8  to fill the reservoir  8 . More particularly, the excess or return fuel from the fuel pressure regulator  20  is directed to the fuel supply conduit  41  via the filtering choke  80 , and is used to power the primary jet pump  43  before being returned to the reservoir  8 . 
     Referring to  FIGS. 7 and 8 , the filtering choke  80  is disposed in a jet pump feed tube  28  that supplies fuel to the fuel supply conduit  41 . The jet pump feed tube  28  is a tube that is secured to an outer surface of the filter housing  24  so as to be aligned with a vertical axis, and has a feed tube inlet  30  at one end and a feed tube outlet  32  at an opposed end. Here, reference to a vertical axis is made with respect to the orientation of the device as illustrated in the figures, and with respect to the orientation of the device when installed in a vehicle that is supported on a level surface. The jet pump feed tube  28  includes a feed tube passageway  34  that extends between the feed tube inlet  30  and the feed tube outlet  32 . The feed tube outlet  32  is connected to the fuel supply conduit  41 , whereby the jet pump feed tube delivers fuel to the fuel supply conduit  41 . 
     The filtering choke  80  is disposed in the jet pump feed tube  28  at a location between the feed tube inlet  30  and the feed tube outlet  32 . In the illustrated embodiment, the filtering choke  80  is positioned mid-way between the feed tube inlet  30  and feed tube outlet  32 , but is not limited to the mid-way position. The filtering choke  80  includes a filtering choke housing  81 , a filter ball  88  that is disposed in the filtering choke housing  81 , and an orifice plate  89  disposed in the filtering choke housing  81  at a location downstream of the filter ball  88 . The filtering choke housing  81  is formed integrally with a surface of the feed tube passageway  34 . The filtering choke housing  81  includes a fluid inlet  83 , a fluid outlet  84  and a choke housing longitudinal axis  85  that extends between the fluid inlet  83  and the fluid outlet  84 . The choke housing longitudinal axis  85  is aligned with the direction of fluid flow through the jet pump feed tube  28 , e.g., aligned with a vertical axis. The filtering choke housing  81  defines a choke housing passageway  82  that extends between the fluid inlet  83  and the fluid outlet  84 . 
     Adjacent to the fluid inlet  83 , the choke housing passageway  82  has a first cross-sectional dimension, for example a first diameter d 1 , that is less than a corresponding dimension, for example a second diameter d 2 , of the feed tube passageway  34 , whereby a first shoulder  94  is formed within the feed tube passageway  34  at the fluid inlet  83 . In some embodiments, the first shoulder  94  may include a beveled portion  96  at the intersection of the shoulder  94  with the choke housing passageway  82 . The beveled portion  96  facilitates insertion of the filter ball  88  into the choke housing passageway  82  during manufacture of the filter choke  80 . 
     The filtering choke housing  81  also includes several filter slots  86  that are formed in a surface of the choke housing passageway  82 . In the illustrated embodiment, fourteen filter slots  86  are provided, but a greater or fewer number of filter slots  86  can be used as is required by the specific application. The filter slots  86  are spaced apart about a circumference of the choke housing passageway  82 , and extend in parallel to the choke housing longitudinal axis  85 . In the illustrated embodiment, the filter slots  86  are equidistantly spaced apart about the circumference of the choke housing passageway  82 , but are not limited to this configuration. 
     The filter ball  88  is disposed in the choke housing passageway  82  at a location corresponding to the location of the filter slots  86 . The filter ball  88  is dimensioned to be press fit within the choke housing passageway  82  such that the filter ball  88  is fixed within the choke housing passageway  82  and abuts the filter slots  86 . In particular, the filter ball  88  is fixed within the choke housing passageway  82  and fully obstructs fluid flow within the housing passageway  82 . However, a filtering choke fluid path  96  is defined between the filter ball  88  and surfaces of the filter slots  86 . The filtering choke fluid path  96  provides fluid communication between the choke housing fluid inlet  83  and the choke housing fluid outlet  84 , and thus also between the feed tube inlet  30  and the feed tube outlet  32 . 
     To provide a filtering function, the filter slots  86  are dimensioned such that objects of a predetermined size are prevented from entering the fluid path  96 . For example, in the illustrated embodiment, the filtering slots  86  are dimensioned to be the same size or smaller than an aperture  90  of the orifice plate  89 , to ensure that the orifice plate aperture  90  does not become obstructed by particles or debris in the fuel. 
     In addition to the filtering choke housing  81  and the filter ball  88 , the filtering choke  80  also includes the orifice plate  89 . The orifice plate  89  is an annular plate that is disposed in the filtering choke housing  81  between the filter slots  86  and the fluid outlet  84 . The orifice plate  89  is oriented transverse to the choke housing longitudinal axis  85 , and protrudes integrally from the filtering choke housing  81 . In the illustrated embodiment, the filter slots  86  terminate at the orifice plate  89 . The orifice plate  89  defines the aperture  90 , which serves a pressure reduction function. As such, a diameter d 3  of the aperture  90  is set based on an amount of pressure reduction that is required within the feed tube  28  as determined by the specific application. For example, the filtering choke  80  may reduce the pressure of the pressurized fuel delivered to the fuel supply conduit  41  from about 5 bars to about 3 bars. Alternatively, the filtering choke  80  may be configured to reduce the pressure of the pressurized fuel delivered to the fuel supply conduit  41  by a different amount. 
     Adjacent to, and upstream of, the orifice plate  89 , the choke housing passageway  82  has a relatively reduced cross-sectional dimension, for example having a fourth diameter d 4 , that is less than a corresponding dimension of the choke housing passageway  82  adjacent to the fluid inlet  83 , e.g., the first diameter d 1 . As a result, a second shoulder  95  is formed within the feed tube passageway  34 . Thus, the choke housing passageway  82  has a reduced diameter portion at the location at which it intersections the orifice plate  89 . The fourth diameter d 4  is less than the diameter d 5  of the filter ball  88 . In addition, the second shoulder  95  is spaced apart from the orifice plate  89  along the choke housing longitudinal axis  85 , and serves to prevent the filter ball  88  from contacting the orifice plate  89  and obstructing the aperture  90 . 
     Referring again to  FIGS. 3, 5 and 6 , the jet pump assembly  40  includes a base  56  integrally formed as a single piece with the fuel supply conduit  41  and the primary jet pump  43 . The base  56  defines an internal chamber  42  having an opening adjacent the bottom of the base  56  through which fuel is drawn in response to fuel being discharged through the primary jet pump  43 . The reservoir  8  includes a receptacle (not shown) sized to receive the base  56  therein. An interference fit between the receptacle and the base  56  of the jet pump assembly  40  may be employed to at least partially secure the jet pump assembly  40  to the reservoir  8 . Alternatively, any of a number of different fasteners or processes may be employed to secure the jet pump assembly  40  to the reservoir  8  (e.g., using screws, quick-connect structures, welding, adhesives, etc.). 
     A one-way valve  22  (for example, an umbrella-style valve) is coupled to the bottom of the reservoir  8  and is positioned within the internal chamber  42  of the base  56 . As is discussed in more detail below, the discharge of fuel through the primary jet pump  43  creates a region of low pressure within the internal chamber  42 , thereby opening the one-way valve  22  to allow fuel in the primary side  6  of the fuel tank  4  to be drawn into the internal chamber  42  and subsequently mixed with the fuel discharged through the primary jet pump  43  within the primary mixing tube  48 . The mixed fuel is then discharged into the reservoir  8  to fill the reservoir  8 . However, shortly after de-activation of the fuel pump  12 , fuel stops flowing through the primary jet pump  43 , allowing the pressure exerted on each side of the one-way valve  22  to equalize which, in turn, allows the valve  22  to close. When the valve  22  is closed, fuel in the reservoir  8  is prevented from back-flowing through the primary jet pump  43  and siphoning to the primary side  6  of the fuel tank  4 . 
     The primary jet pump  43  also includes a primary nozzle  44  positioned adjacent the internal chamber  42  of the base  56  and a primary mixing tube  48 . The primary nozzle  44  includes a primary nozzle inlet  45  at one end that communicates with the fuel supply conduit  41 , and a tapered primary nozzle outlet  46  at an opposed end. A longitudinal axis  47  of the primary jet pump  43  extends between the primary nozzle inlet  45  and the primary nozzle outlet  46 , and is perpendicular to the direction of fluid flow through the fuel supply conduit  41 . The primary nozzle  44  discharges into the primary mixing tube  48 , which is aligned with the primary jet pump longitudinal axis  47 . 
     As described above, discharge of fuel through the primary nozzle  44  creates a region of low pressure within the internal chamber  42  to open the one-way valve  22  and draw fuel from the primary side  6  of the fuel tank  4  into the chamber  60 , where the fuel is mixed with fuel discharged through the primary nozzle  44  in the primary mixing tube  48 . The mixed fuel is then discharged from the primary mixing tube  48  into the reservoir  8 . 
     The jet pump assembly  40  also includes a second or secondary jet pump  49 . In the illustrated embodiment, the secondary jet pump  49  is integrally formed as a single piece with the fuel supply conduit  41 . The secondary jet pump  49  includes a secondary nozzle  50  positioned adjacent the fuel supply conduit  41  and overlying the primary nozzle  44 , and a secondary mixing tube  54 . The secondary nozzle  50  includes a secondary nozzle inlet  51  at one end that communicates with the fuel supply conduit  41  at a location upstream relative to the primary nozzle inlet  45 . The secondary nozzle  50  includes a tapered secondary nozzle outlet  52  at an opposed end relative to the secondary nozzle inlet  51 . A longitudinal axis  53  of the secondary jet pump  49  extends between the secondary nozzle inlet  51  and the secondary nozzle outlet  52 , and is perpendicular to the direction of fluid flow through the fuel supply conduit  41 . The secondary nozzle  50  discharges into the secondary mixing tube  54 , which is aligned with the secondary jet pump longitudinal axis  53 . 
     The secondary jet pump  49  is in fluid communication with the fuel supply conduit  41  to receive pressurized fuel from the fuel supply conduit  41  during operation of the fuel pump  12 . As shown in  FIG. 6 , the primary and secondary jet pumps  43 ,  40  are fluidly connected to the fuel supply conduit  41  in a parallel arrangement. 
     Referring to  FIGS. 9 and 10 , a jet pump choke  120  is disposed in the fuel supply conduit  41  between the secondary nozzle inlet  51  and the primary nozzle inlet  45 . The jet pump choke  120  includes a choke housing  121  that is formed integrally with the inner surface of the fuel supply conduit  41 , and a choke ball  124  that is disposed within the choke housing  121 . The choke housing  121  defines a choke passageway  122 . The choke passageway  122  extends between the fuel supply conduit  41  and the primary nozzle inlet  45 , in parallel to a direction of fluid flow through the fuel supply conduit  41  and perpendicular to the primary nozzle longitudinal axis  47 . A single choke slot  123  is formed in the choke passageway  122 . The choke slot  123  extends in parallel to a direction of fluid flow through the fuel supply conduit  41 . 
     The choke ball  124  is disposed in the choke passageway  122  at a location corresponding to the location of the choke slot  123 . The choke ball  124  is dimensioned to be press fit within the choke passageway  122  such that the choke ball  124  is fixed within the choke passageway  122  and abuts the choke slot  123 . In particular, the choke ball  124  is fixed within the choke passageway  122  and fully obstructs fluid flow within the choke passageway  122 . However, a choke fluid path  126  is defined between the choke ball  124  and surfaces of the choke slot  123 . The choke fluid path  126  provides fluid communication between the fuel supply conduit and the primary nozzle inlet  45 . 
     Referring to  FIG. 11 , a cross-section of the choke fluid path  126  that is perpendicular to a direction of fluid flow through the choke fluid path  126  defines a first area A 1 . The first area A 1  is small relative to a second area A 2  that is defined by a cross-section of the fuel supply conduit  41  that is perpendicular to a direction of fluid flow through the fuel supply conduit  41 , as well as a third area A 3  that is defined by a cross-section of the choke passageway  122  that is perpendicular to a direction of fluid flow through the choke passageway  122 . As a result, choke slot  123  serves a pressure reduction function. In particular, the jet pump choke  120  reduces the pressure of the pressurized fuel delivered to the primary nozzle inlet  45  relative to the pressure of the pressurized fuel delivered to the secondary nozzle inlet  51 . The dimensions of the choke slot  123  are set based on an amount of pressure reduction that is required within the choke passageway  122  as determined by the specific application. For example, the jet pump choke  120  may reduce the pressure of the pressurized fuel delivered to the primary nozzle inlet  45  from about 3 bars to about 1 bar. Alternatively, the jet pump choke  120  may be configured to reduce the pressure of the pressurized fuel delivered to primary nozzle inlet  45  by a different amount. 
     Referring to  FIGS. 5, 6 and 9 , in the illustrated embodiment of the jet pump assembly  40 , the mixing tubes  48 ,  54  of the primary and secondary jet pumps  43 ,  49  are stacked one on top of the other (i.e., vertically aligned) such that the mixing tubes  48 ,  54  share a common wall  64 . Alternatively, the mixing tubes  48 ,  54  may be situated side-by-side or horizontally aligned, or situated diagonally with respect to one another, while sharing a common wall. Each of the primary and secondary jet pumps  48 ,  49  includes a plug (e.g., a ball bearing  62 ) positioned within an aperture  61  formed in a respective outer wall of the jet pumps  43 ,  49  while molding the fuel supply conduit  41 , the base  56 , and the jet pumps  43 ,  49  as a single piece. Specifically, the apertures  61  may be formed by respective slides used in an injection molding process to mold the passageways of the nozzles  44 ,  50  in the respective jet pumps  43 ,  49 . As such, insertion of the ball bearings  62  into the apertures  61  (via an interference fit, for example) effectively blocks the apertures  61  to substantially prevent fuel flow through the apertures  61 . 
     The jet pump assembly  40  also includes a plug  60  integrally formed as a single piece with the secondary jet pump  49 . In the illustrated construction of the jet pump assembly  40 , the plug  60  and the secondary mixing tube  54  are connected by an integral tether  63  to close an end  65  of the secondary mixing tube  54  opposite the secondary nozzle  50 . As a result, fuel is prevented from being discharged from the end  65  of the secondary mixing tube  54 . Alternatively, the plug  60  may be configured as a ball bearing that is a separate and distinct component from the secondary mixing tube  54 . 
     The jet pump assembly  40  further includes an inlet conduit  58  integrally formed as a single piece with the secondary jet pump  49 . The inlet conduit  58  fluidly communicates the secondary jet pump  49  and the secondary side  7  of the saddle-style fuel tank  4  to allow the secondary jet pump  49  to draw fuel from the secondary side  7  of the fuel tank  4 . The inlet conduit  58  includes an opening  66  positioned adjacent the secondary nozzle  50  through which fuel is drawn into the secondary mixing tube  54  as a result of a low-pressure region surrounding the secondary nozzle  50  and in the inlet conduit  58  in response to fuel discharge through the secondary nozzle  50 . In the illustrated construction of the jet pump assembly  40 , the inlet conduit  58  extends substantially perpendicularly from the secondary mixing tube  54  and in a direction substantially parallel with the fuel supply conduit  41 . Alternatively, the inlet conduit  58  may extend from the secondary mixing tube  54  at an oblique angle. The inlet conduit  58  includes a plurality of barbs  67  arranged about its outer peripheral surface that facilitate securing a rubber or plastic “crossover” tube  68  to the inlet conduit  58 . Such a crossover tube  68  (shown schematically in  FIGS. 3 and 4 ) extends from the inlet conduit  58 , over the hump of the saddle-style fuel tank  4 , and into the secondary side  7  of the fuel tank  4 . 
     The jet pump assembly  40  may optionally include a bracket  57  integrally formed as a single piece with the inlet conduit  58 . The bracket  534  includes a substantially circular cross-sectional shape and facilitates alignment of an inlet end of the fuel supply conduit  41  with the feed tube outlet  32 . 
     The jet pump assembly  40  also includes a stand pipe  59  integrally formed as a single piece with the secondary jet pump  49 . In the illustrated embodiment of the jet pump assembly  40 , the stand pipe  59  extends substantially perpendicularly from the secondary mixing tube  54  and in a direction substantially parallel with the inlet conduit  58  and the fuel supply conduit  41 . Alternatively, the stand pipe  59  may extend from the secondary mixing tube  54  at an oblique angle. The stand pipe  59  includes distal open end  69  that remains exposed or uncovered when the jet pump assembly  40  is positioned in the reservoir  8 . As is described in more detail below, the stand pipe  59  substantially prevents fuel in the reservoir  8 , below the distal open end  69  of the stand pipe  59  and outside of the jet pump assembly  40 , from siphoning out of the reservoir  8  and into the secondary side  7  of the saddle-style fuel tank  4 . 
     In operation of the fuel pump  12  and the jet pump assembly  40 , some of the pressurized fuel output by the fuel pump  12  is diverted toward the jet pump assembly  40  to power the jet pump assembly  40  and fill the reservoir  8  with fuel (see  FIG. 3 ). As discussed above, the pressure of the diverted fuel is reduced by the filtering choke  80  prior to entering the fuel supply conduit  41 . The pressurized fuel in the fuel supply conduit  41  then feeds both the primary and secondary jet pumps  43 ,  49 . As the pressurized fuel is discharged through the primary nozzle  44  of the primary jet pump  43 , a low-pressure region within the internal chamber  42  of the base  56  is created, thereby opening the one-way valve  22  to allow fuel from the primary side  6  of the fuel tank  4  to be drawn into the internal chamber  42 . Fuel drawn into the internal chamber  42  of the base  56  is mixed with the fuel discharged through the primary nozzle  44  in the primary mixing tube  48 , and is subsequently discharged into the reservoir  8  to fill the reservoir  8 . While this occurs, pressurized fuel discharged through the secondary nozzle  50  of the secondary jet pump  49  creates a low-pressure region surrounding the secondary nozzle  50  and within the inlet conduit  58 , thereby drawing fuel from the secondary side  7  of the fuel tank  4  into the inlet conduit  58  (via the crossover tube  68 ). Fuel drawn through the inlet conduit  58  is mixed with fuel discharged through the secondary nozzle  50  in the secondary mixing tube  54 , and the mixed fuel is discharged upwardly through the stand pipe  59  and into the reservoir  8  to fill the reservoir  8  with fuel from the secondary side  7  of the fuel tank  4 . 
     Upon deactivation of the fuel pump  12 , the one-way valve  22  closes to substantially prevent fuel in the reservoir  8  from back-flowing through the primary jet pump  43  and siphoning to the primary side  6  of the fuel tank  4 . Some fuel in the reservoir  8  may, however, back-flow through the stand pipe  59 , the secondary jet pump  49 , and the inlet conduit  58  and siphon to the secondary side  7  of the fuel tank  4 . As the level of fuel in the reservoir  8  reaches the distal open end  69  of the stand pipe  59 , the remaining fuel in the stand pipe  59 , the secondary jet pump  49 , and the inlet conduit  58  may continue to siphon into the secondary side  7  of the fuel tank  4 . However, any fuel in the reservoir  8  below the distal open end  69  of the stand pipe  59  and outside of the jet pump assembly  40  is prevented from siphoning into the secondary side  7  of the fuel tank  4 , thereby maintaining a sufficient supply of fuel in the reservoir  8  in anticipation of reactivation of the fuel pump  12 . 
     With reference to  FIG. 4 , operation of the jet pump assembly  40  is substantially similar as that described above with respect to  FIG. 3 , except the jet pump assembly  40  is powered by return fuel from the fuel pressure regulator  20  rather than receiving fuel directly from the output of the fuel pump  12 . 
     Referring to  FIGS. 12-14 , although in the illustrated embodiment, the filtering choke housing  81  is formed integrally with the jet pump feed tube  28 , the filtering choke  80  is not limited to this configuration. For example, in some embodiments of the vehicle fuel pump module  2 , an alternative embodiment filtering choke  280  is provided. The filtering choke  280  illustrated in  FIGS. 12-14  is similar to the filtering choke  80  illustrated in  FIGS. 7 and 8 , and common elements have common reference numbers. However, the filtering choke  280  illustrated in  FIGS. 12-14  differs from the earlier-described embodiment in that the filtering choke  280  has a filtering choke housing  281  that is formed separately from the feed tube  28 , and is configured to be press fit within the feed tube passageway  34  during manufacture. To this end, the filtering choke housing  281  has an outer surface  282  that is shaped and dimensioned to a) facilitate insertion of the filtering choke housing  281  into the feed tube  28  during manufacture, and b) provide a sealed press fit within the feed tube passageway  34 , whereby all fluid passing through the feed tube passageway  34  passes through the filtering choke housing  281 . For example, the filtering choke housing outer surface  282  includes an annular protrusion  283  that is formed at the fluid inlet  83 . The annular protrusion  283  has the same shape as the surface of the feed tube passageway  34 , and a dimension that provides a sealed press fit therewith. In addition, the filtering choke housing outer surface  282  includes a radially inwardly tapered portion  284  formed at the fluid outlet  284 . The tapered portion  284  of the filtering choke housing at the outer surface  282  does not intersect the choke housing passageway  282 . The tapered portion  284  facilitates insertion of the filtering choke housing  281  into the feed tube  28  during manufacture. 
     Various features of the invention are set forth in the following claims.