Patent Publication Number: US-7717090-B2

Title: Fuel-feeding devices

Description:
This application claims priority to Japanese patent application serial number 2007-320659, the contents of which are incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   The present invention relates to a fuel-feeding device for feeding liquid fuel contained in a fuel tank of an automobile to an automobile engine (an internal-combustion engine). 
   A fuel-feeding device is taught by, for example, Japanese Laid-Open Patent Publication No. 2005-69171. This fuel-feeding device includes a reservoir cup disposed in a fuel tank, a fuel pump capable of feeding (pumping) liquid fuel contained in the fuel tank to an engine via a feeding port, a pressure regulator capable of controlling a pressure of the liquid fuel fed to the engine (i.e., a fuel pressure), and a jet pump. The jet pump is arranged and constructed to inject the pressurized liquid fuel pumped from a relief port of the fuel pump into the reservoir cup, thereby introducing (drawing) the liquid fuel outside of the reservoir cup into the reservoir cup with the injected liquid fuel. 
   However, according to the known fuel-feeding device, it is not possible to control a flow rate of the liquid fuel pumped from the relief port of the fuel pump. Therefore, when the liquid fuel is pumped from the feeding port of the fuel pump to the engine in a reduced flow rate, a flow rate of the liquid fuel from the relief port of the fuel pump toward the jet pump can be relatively higher than the flow rate of the liquid fuel from the feeding port of the fuel pump toward the engine. That is, when a reduced volume of liquid fuel is pumped from the fuel pump, a substantial portion of the pumped liquid fuel is fed to the jet pump and not to the engine. Therefore, even if the reduced volume of liquid fuel should be fed to the engine, the fuel pump must be actuated to pump a relatively large volume of liquid fuel. That is, the fuel pump must be actuated at a relatively high speed (large load) in order to feed the reduced volume of liquid fuel to the engine. This means that when the reduced volume of liquid fuel should be fed to the engine, the fuel pump must be wastefully actuated. 
   Thus, there is a need in the art for an improved fuel-feeding device for feeding liquid fuel of an engine. 
   BRIEF SUMMARY OF THE INVENTION 
   For example, in one embodiment of the present invention, a fuel-feeding device may include a reservoir cup disposed in a fuel tank that contains liquid fuel therein, a fuel pump capable of feeding the liquid fuel contained in the reservoir cup to an engine, a pressure regulator capable of controlling a fuel pressure of the liquid fuel fed to the engine from the fuel pump, a jet pump arranged and constructed to receive a part of the pressurized liquid fuel pumped from the fuel pump via a fuel jet path, so as to introduce liquid fuel outside the reservoir cup into to the reservoir cup with the aid of flow of the pressurized liquid fuel, and a flow rate control valve disposed in the fuel jet path. The flow rate control valve is arranged and constructed to control a flow rate of the pressurized liquid fuel fed to the jet pump depending upon a pumping rate of the pressurized liquid fuel pumped from the fuel pump. 
   According to the fuel-feeding device thus constructed, the liquid fuel in the reservoir cup can be fed to the engine by the fuel pump. Further, a pressure of the liquid fuel pumped out of the fuel pump can be controlled by the pressure regulator. Further, the pressurized liquid fuel pumped out of the fuel pump can be fed to the jet pump via the fuel jet path. The jet pump can be actuated with the aid of flow of the liquid fuel, so that the liquid fuel outside of the reservoir cup is introduced into the reservoir cup. The flow rate control valve may preferably change a flow rate of the pressurized liquid fuel fed to the jet pump depending upon a pumping rate of the pressurized liquid fuel pumped from the fuel pump. Therefore, when the pumping rate of the liquid fuel pumped from the fuel pump is low, the flow rate of the pressurized liquid fuel fed to the jet pump may preferably be reduced. As a result, a flow rate of the liquid fuel fed to the engine may preferably be prevented from being excessively reduced. Thus, it is not necessary to actuate the fuel pump  16  at a relatively high speed in order to fed the reduced volume of liquid fuel to the engine. In other words, when the reduced volume of liquid fuel should be fed to the engine, a load applied to the fuel pump can be effectively reduced. 
   Other objects, features, and advantages, of the present invention will be readily understood after reading the following detailed description together with the accompanying drawings and the claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic diagram of a fuel-feeding device according to a first embodiment of the present invention; 
       FIG. 2  is a cross-sectional view of a fuel pump used in the fuel-feeding device; 
       FIG. 3  is a schematic diagram of a fuel-feeding device according to a second embodiment of the present invention; 
       FIG. 4  is a partially cross-sectional view of a fuel pump having a flow control valve used in the fuel-feeding device; 
       FIG. 5  is an enlarged cross-sectional view of the flow control valve; 
       FIG. 6  is a view similar to  FIG. 5 , which illustrate a first modified form of the flow control valve; and 
       FIG. 7  is a view similar to  FIG. 5 , which illustrate a second modified form of the flow control valve. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Next, the representative embodiments of the present invention will be described with reference to the drawings. 
   First Embodiment 
   A first embodiment of the present invention will be described with reference to  FIGS. 1 and 2 . This embodiment of the present invention is directed to a fuel-feeding device for use in a vehicle engine. 
   As shown in  FIG. 1 , the fuel-feeding device  10  may preferably be disposed in a fuel tank  12  of a vehicle (not shown) in which liquid fuel is contained. The fuel-feeding device  10  may preferably include a reservoir cup  14 , an immersion type fuel pump  16  capable of feeding (pumping) the liquid fuel contained in the fuel tank  12  to an engine (not shown), a fuel filter  18 , a pressure regulator  20  capable of controlling a pressure (i.e., a fuel pressure) of the liquid fuel fed to the engine, and a jet pump  22 . The pressure regulator  20  is attached to the fuel pump  16 . 
   The reservoir cup  14  (which may be referred to as a reservoir container or a sub-tank) may preferably be positioned on a bottom surface of the fuel tank  12 . The reservoir cup  14  may preferably have a cylindrical cup shape and having a cylindrical side  6   a  wall portion  14   a  and a bottom wall portion  14   b . A valve port  23  is formed in the bottom wall portion  14   b  of the reservoir cup  14 . A check valve  24  is attached to the valve port  23 . The check valve  24  is arranged and constructed to be opened when a pressure of the liquid fuel outside of the reservoir cup  14  is higher than the pressure of the liquid fuel inside of the reservoir cup  14 , thereby allowing flow of the liquid fuel outside of the reservoir cup  14  into the reservoir cup  14 . Also, the check valve  24  is arranged and constructed to be closed when the pressure of the liquid fuel outside of the reservoir cup  14  is lower than the pressure of the liquid fuel inside of the reservoir cup  14 , thereby preventing reverse flow of the liquid fuel inside of the reservoir cup  14  toward outside of the reservoir cup  14 . 
   The fuel pump  16  is disposed in the reservoir cup  14 . As shown in  FIG. 2 , the fuel pump  16  may preferably be composed of a motor portion  26  and a pump portion  27 . That is, the fuel pump  16  is constructed as a fuel pump integrated with a motor. The motor portion  26  may preferably have a motor housing  33 , and an electric motor  26   a  that is disposed in the motor housing  33 . Conversely, the pump portion  27  may preferably have a pump housing  28  that is attached to the motor housing  33 , and an impeller  29  that is operatively disposed in the pump housing  28 . 
   The pump housing  28  has an annular pump cavity  30  that extends along a periphery of the impeller  29 . The pump cavity  30  may preferably have a C-shape in cross section. Also, the pump housing  28  has a fuel inlet port  31  that communicates with the pump cavity  30  and opening into the reservoir cup  14 . The fuel inlet port  31  may preferably be provided with a fuel filtering bag  32  that is disposed in the reservoir cup  14 . Further, the pump housing  28  has a fuel outlet port  34  that communicates with the pump cavity  30  and opening into the motor housing  33 . The impeller  29  of the pump portion  27  is coupled to a motor shaft  26   b  of the motor  26   a , so as to be rotated when the motor  26   a  is actuated. As will be appreciated, upon rotation of the impeller  29 , the liquid fuel in the reservoir cup  14  (the fuel tank  12 ) can be introduced into the motor housing  33  via the fuel inlet port  31 , the pump cavity  30  and the fuel outlet port  34 . 
   Further, the pump housing  28  has a vapor jet port (a relief port)  38  that communicates with the pump cavity  30  and opening into the reservoir cup  14 . The vapor jet port  38  is arranged and constructed to discharge a vapor-containing liquid fuel (a vaporized fuel) in the pump cavity  30  into the reservoir cup  14  therethrough. 
   The motor housing  33  of the fuel pump  16  has a pair of (first and second) outlet ports  35  and  36  ( FIG. 1 ) that are juxtaposed to each other. The first and second outlet ports  35  and  36  communicate with the pump cavity  30  via the fuel outlet port  34  and are arranged and constructed such that the liquid fuel introduced into the motor housing  33  can be pumped out therethrough. As shown in  FIG. 1 , the first outlet port  35  communicates with the engine via a first conduit pipe  50 , the fuel filer  18  and a second conduit pipe  52 . Thus, the fuel pump  16  (the fuel inlet port  31 , the pump cavity  30 , the fuel outlet port  34 , the motor housing  33  and the first outlet port  35 ), the first conduit pipe  50 , the fuel filer  18  and the second conduit pipe  52  communicate with each other, so as to constitutes a continuous path. This path may be referred to as a fuel feeder path. The fuel feeder path thus formed may preferably communicate between the fuel pump  16  and the engine. Conversely, the second outlet port  36  is positioned upstream of the first outlet port  35  in the fuel feeder path and communicates with the jet pump  22  via a fuel jet conduit pipe  37 . The fuel jet conduit pipe  37  constitutes a continuous path, which path may be referred to as a fuel jet path or branched path. 
   Thus, the fuel jet path is substantially branched from the fuel feeder path between the pump portion  27  of the fuel pump  16  and the pressure regulator  20  via the second outlet port  36  that is positioned upstream of the first outlet port  35 . Further, the second outlet port  36  constitutes a branching portion of the fuel jet path. 
   As best shown in  FIG. 1 , a pressure holding valve  40  is disposed in the first outlet port  35 . The pressure holding valve  40  may preferably be composed of a squeezing portion  41 , a valve seat  41   a  formed in a downstream side (an upper side in  FIG. 1 ) of the squeezing portion  41 , a valve body  43 , a coil spring  44  ( FIG. 2 ), and a spring stopper  45  ( FIG. 2 ) secured to the first outlet port  35  by crimping. The valve body  43  is movably disposed so as to move toward and away from the valve seat  41   a . The coil spring  44  is positioned between the valve body  43  and the spring stopper  45 , so as to prevent the valve body  43  from inclining. 
   When the liquid fuel is pumped upon actuation of the fuel pump  16  (upon starting of the engine), the valve body  43  can be spaced away from the valve seat  41   a  by a pressure of the pumped liquid fuel. As a result, the pressure holding valve  40  can be opened, so that the liquid fuel can be fed to the first conduit pipe  50  via the first outlet port  35 . Conversely, when the fuel pump  16  is deactuated (when the engine is stopped), the valve body  43  can be pressed to the valve seat  41   a  by a pressure of the liquid fuel in the first conduit pipe  50 , so that the pressure holding valve  40  can be closed. As a result, a residual pressure of the liquid fuel in the first conduit pipe  50  can be maintained. 
   As previously described, the fuel jet path is branched from the fuel feeder path between the pump portion  27  of the fuel pump  16  and the pressure regulator  20  via the branching portion (the second outlet port  36 ) that is positioned upstream of the first outlet port  35 . This means that the squeezing portion  41  (which may be referred to as a fuel feeder path squeezing portion) of the pressure holding valve  40  is positioned downstream of the branching portion (the second outlet port  36 ) in the fuel feeder path between the pump portion  27  of the fuel pump  16  and the pressure regulator  20 , because the pressure holding valve  40  is disposed in the first outlet port  35 . 
   As shown in  FIG. 1 , the fuel filter  18  is disposed in the reservoir cup  14  so as to encircle the fuel pump  16 . The fuel filter  18  may preferably be composed of a filter housing  47  having various shapes (e.g., circular shape, D-shape and C-shape) in cross section and a filter element  48  received in the filter housing  47 . An inlet port  47   a  is formed in an upper wall of the filter housing  47 . The inlet port  47   a  is connected to the first outlet port  35  of the fuel pump  16  via the first fuel conduit  50 . Further, an outlet port  47   b  is formed in the upper wall of the filter housing  47 . The outlet port  47   b  is connected to the engine via the second fuel conduit  52 . In particular, the outlet port  47   b  is connected to a delivery tube (not shown) having injectors or fuel injection valves (not shown) via the second fuel conduit  52 . Therefore, the liquid fuel pumped from the first outlet port  35  of the fuel pump  16  can be fed to the delivery tube via the first fuel conduit  50 , the fuel filter  18  and the second fuel conduit  52  and then be injected into combustion chambers (not shown) via the injectors. 
   As shown in  FIG. 1 , the pressure regulator  20  is attached to a lower wall of the filter housing  47  of the fuel filter  18 . The pressure regulator  20  is arranged and constructed to control the fuel pressure (the pressure of the liquid fuel fed to the second fuel conduit  52  from the fuel pump  16 ). Also, the pressure regulator  20  is arranged and constructed to discharge excess liquid fuel (return liquid fuel) generated by pressure controlling operation of the pressure regulator  20  into the reservoir cup  14 . Further, because the pressure regulator  20  has a known structure, a detailed description of the pressure regulator may be omitted. 
   As shown in  FIG. 1 , the jet pump  22  is disposed in the reservoir cup  14 , so as to be positioned closer to a bottom wall  14   b  of the reservoir cup  14 . The jet pump  22  may preferably be composed of a horizontally extending cylindrical pump housing  54 , and a tapered nozzle  55  that is disposed in the pump housing  54 . A suction port  56  is formed in the pump hosing  54 , so as to be positioned adjacent to a tip of the nozzle  55 . Conversely, an opening  57  is formed in the bottom wall  14   b  of the reservoir cup  14 , so as to be aligned with the suction port  56  of the pump housing  54 . A proximal end of the pump housing  54  is connected to the fuel jet conduit pipe  37 , so that the pressurized liquid fuel (drive fuel) pumped out of the second outlet port  36  of the fuel pump  16  can be fed to the jet pump  22  via the fuel jet conduit pipe  37 . When the pressurized liquid fuel (drive fuel) fed to the jet pump  22  via the fuel jet conduit pipe  37  is injected from the nozzle  55 , the liquid fuel outside of the reservoir cup  14  is introduced (drawn) into the pump housing  54  via the suction port  56  through the opening  57  of the reservoir cup  14 . The liquid fuel is then introduced into the reservoir cup  14  through a distal end of the pump housing  54  with the liquid fuel injected from the nozzle  55 . Thus, the jet pump  22  may function to introduce the liquid fuel outside of the reservoir cup  14  into the reservoir cup  14  with the aid of flow of the drive fuel. 
   As shown in  FIG. 1 , a flow rate control valve  60  is disposed in the fuel jet conduit pipe  37 , so as to control a flow rate (which will be referred to as a jet fuel flow rate Q 1 ) of the drive fuel fed to the jet pump  22  depending upon a total flow rate (which will be referred to as a pumping rate PQ) of the pressurized liquid fuel pumped from the fuel pump  16 . The flow rate control valve  60  may preferably be positioned at an upstream portion of the fuel jet conduit pipe  37 . In particular, the flow rate control valve  60  may preferably be positioned adjacent to the second outlet port  36 . The flow rate control valve  60  may preferably be composed of a valve seat  61  secured to the fuel jet conduit, pipe  37 , a valve body  62  positioned downstream (an upper side in  FIG. 1 ) of the valve seat  61 , a spring (coil spring)  63 , and a spring stopper  64  secured to the fuel jet conduit pipe  37 . The valve body  62  is capable of moving toward and away from the valve seat  61 . The coil spring  63  is positioned between the valve body  62  and the spring stopper  64 , so as to normally bias the valve body  62  toward the valve seat  61  (toward downwardly in  FIG. 1 ). Further, the spring stopper  64  may preferably be arranged and constructed such that the liquid fuel can freely flow therethrough. 
   When the liquid fuel is pumped upon actuation of the fuel pump  16 , the valve body  62  can be spaced away from the valve seat  61  against a spring force of the coil spring  63  by the pressure of the pumped liquid fuel. As a result, the flow rate control valve  60  can be opened, so that the liquid fuel can flow to the fuel jet pipe  37  (the fuel jet path) via the second outlet port  36 . As will be recognized, a moving distance (a valve stroke) of the valve body  62  can be changed depending upon a pumping pressure of the fuel pump  16  (i.e., a pressure of the pumped liquid fuel pumped from the fuel pump  16 ). As a result, a flow rate of the drive fuel fed to the jet pump  22  can be changed depending upon the pumping pressure of the fuel pump  16 . Conversely, when the fuel pump  16  is deactuated, the valve body  62  can be pressed to the valve seat  61  by the spring of the coil spring  63 . As a result, the flow rate control valve  60  can be closed, so that the liquid fuel pumped from the fuel pump  16  can be prevented from flowing into the fuel jet pipe  37 . That is, the moving distance of the valve body  62  can be changed depending upon the pumping pressure of the fuel pump  16 , so that a valve opening area of the flow rate control valve  60  (which area corresponds to an opening area of the fuel jet pipe  37 ) can be changed. Thus, the flow rate control valve  60  may preferably be constructed as a pressure-dependent variable valve. 
   Next, operation of the fuel-feeding device  10  thus constructed will be described in detail. 
   When the fuel pump  16  is actuated (when the motor  26   a  is actuated), the impeller  29  coupled to the motor shaft  26   b  of the motor  26   a  is rotated, so that the liquid fuel in the reservoir cup  14  can be introduced into the motor housing  33  via the fuel filtering bag  32 , the fuel inlet port  31 , the pump cavity  30  and the fuel outlet port  34 . The liquid fuel introduced into the motor housing  33  is then pumped out of the first and second outlet ports  35  and  36  of the fuel pump  16 . The liquid fuel pumped out of the first outlet port  35  of the fuel pump  16  is fed to the fuel filter  18  via the first fuel conduit  50 , so as to be filtrated by the filter element  48  of the fuel filter  18 . The filtered liquid fuel is then fed to the engine via the second fuel conduit  52 . Further, the pressure of the liquid fuel pumped out of the first outlet port  35  is controlled by the pressure regulator  20  attached to the fuel filter  18 . The excess liquid fuel (the return liquid fuel) generated by the pressure controlling operation of the pressure regulator  20  is discharged from the pressure regulator  20  into the reservoir cup  14 . 
   Conversely, the pressurized liquid fuel pumped from the second outlet port  36  of the fuel pump  16  is fed to the jet pump  22  via the fuel jet conduit pipe  37 . The pressurized liquid fuel fed to the jet pump  22  is injected from the nozzle  55 . As a result, as previously described, the liquid fuel outside of the reservoir cup  14  is introduced (drawn) into the pump housing  54  via the suction port  56  through the opening  57  of the reservoir cup  14 . The liquid fuel thus introduced is then transferred to the reservoir cup  14  through the distal end of the pump housing  54  with the liquid fuel injected from the nozzle  55 . 
   Further, when the fuel pump  16  is deactuated, the pressure holding valve  40  is closed by the pressure of the liquid fuel in the fuel feeder path (the first conduit pipe  50 , the fuel filer  18  and the second conduit pipe  52 ). As a result, the pressure of the liquid fuel in the fuel feeder path can be maintained as the residual pressure. Conversely, at this time, the flow rate control valve  60  is closed by the spring force of the coil spring  63 . 
   As described above, the fuel feeder path squeezing portion (the squeezing portion  41  of the pressure holding valve  40 ) is disposed in the first outlet port  35  that is positioned downstream of the second outlet port  36  (the branching portion) in the fuel feeder path between the pump portion  27  of the fuel pump  16  and the pressure regulator  20 . Therefore, when the fuel pump  16  is actuated, a pressure (which will be referred to as an upstream fuel pressure P 2 ) of the liquid fuel in upstream of the fuel feeder path squeezing portion (the squeezing portion  41 ) may preferably be increased. 
   Also, as will be recognized, depending on the pumping rate PQ of the pressurized liquid fuel pumped from the fuel pump  16 , a flow rate (which will be referred to as a squeezed fuel flow rate Q) of the liquid fuel passing through the fuel feeder path squeezing portion (the squeezing portion  41 ) may preferably be changed. The squeezed fuel flow rate Q can be generally determined by the following equation:
 
 Q=QE+Q 3
 
where QE is a flow rate (feed fuel flow rate) of the liquid fuel fed to the engine after the pressure controlling operation of the pressure regulator  20  is performed, and Q 3  is a flow rate (return fuel flow rate) of the excess liquid fuel (the return liquid fuel) generated and discharged by the pressure controlling operation of the pressure regulator  20 .
 
   Generally, when the squeezed fuel flow rate Q is low, the upstream fuel pressure P 2  is relatively low. Conversely, when the squeezed fuel flow rate Q is high, the upstream fuel pressure P 2  is relatively high. 
   The flow rate control valve  60  disposed in the fuel jet conduit pipe  37  may preferably be positioned upstream of the fuel feeder path squeezing portion (the squeezing portion  41 ) in the fuel feeder path. Therefore, when the upstream fuel pressure P 2  is relatively low, the moving distance of the valve body  62  of the flow rate control valve  60  is relatively reduced or shortened. As a result, the flow rate (the jet fuel flow rate Q 1 ) of the liquid fuel fed to the jet pump  22  via the fuel jet conduit pipe  37  can be reduced. Conversely, when the upstream fuel pressure P 2  is relatively high, the moving distance of the valve body  62  of the flow rate control valve  60  is relatively increased or lengthened. As a result, the jet fuel flow rate Q 1  can be increased. 
   Thus, depending on the pumping rate PQ of the pressurized liquid fuel pumped from the fuel pump  16 , the jet fuel flow rate Q 1  can be proportionally changed. As a result, a flow rate (which will be referred to as an introduction fuel flow rate Q 2 ) of the liquid fuel introduced into the reservoir cup  14  from outside of the reservoir cup  14  by the jet pump  22  can be proportionally changed. Therefore, the introduction fuel flow rate Q 2  can be controlled so as to have a desired rate corresponding to the feed fuel flow rate QE (Q 2 ≧QE). 
   According to the fuel-feeding device  10  ( FIG. 1 ), the flow rate control valve  60  disposed in the fuel jet conduit pipe  37  may preferably change the jet fuel flow rate Q 1  (i.e., the flow rate of the liquid fuel fed to the jet pump  22 ) depending upon the pumping rate PQ of the pressurized liquid fuel pumped from the fuel pump  16 . Therefore, when the pumping rate PQ of the liquid fuel pumped from the fuel pump  16  is low (i.e., when the pumping pressure of the fuel pump  16  is low), the jet fuel flow rate Q 1  may preferably be reduced depending upon the pumping rate PQ. As a result, the squeezed fuel flow rate Q (the feed fuel flow rate QE) may preferably be prevented from being excessively reduced. That is, when the pumping pressure of the fuel pump  16  is low, the squeezed fuel flow rate Q may preferably be relatively increased compared to the jet fuel flow rate Q 1 . Therefore, when a reduced volume of liquid fuel should be fed to the engine (i.e., when the feed fuel flow rate QE is low), the fuel pump  16  can be actuated at a relatively low speed (low load). This may lead to a reduction of power consumption and a long service life of the fuel pump  16 . 
   Further, at the start of actuation of the fuel pump  16 , the pumping rate PQ of the liquid fuel pumped from the fuel pump  16  is low, so that the flow rate control valve  60  can be substantially closed. Therefore, the fuel pressure of the liquid fuel fed to the fuel feeder path from the fuel pump  16  can be quickly increased to a desired pressure (which may be referred to as a system fuel pressure). This may lead to improved startability of the engine. 
   Further, the suction fuel flow rate Q 2  (the flow rate of the liquid fuel introduced into the reservoir cup  14  by the jet pump  22 ) can be changed depending upon the pumping rate PQ of the pressurized liquid fuel pumped from the fuel pump  16  over a wide range from a condition in which the pumping rate PQ is low (i.e., a low pumping pressure condition of the fuel pump  16 ) to a condition in which the pumping rate PQ is high (i.e., a high pumping pressure condition of the fuel pump  16 ). The change of the suction fuel flow rate Q 2  can be performed without changing a bore size of the nozzle  55  of the jet pump  22 . This may lead to a reduced manufacturing cost of the fuel-feeding device  10 . 
   Further, the fuel pump  16  may preferably be connected to a control unit (not shown) such that the pumping rate PQ can be controllably changed continuously or discontinuously. 
   As described above, the flow rate control valve  60  may preferably be constructed as the pressure-dependent variable valve. That is, the moving distance of the valve body  62  can be changed depending upon the pumping pressure of the fuel pump  16 , so that the valve opening area of the flow rate control valve  60  can be changed. As a result, the flow rate (the jet fuel flow rate Q 1 ) of the liquid fuel fed to the jet pump  22  via the fuel jet conduit pipe  37  can be easily changed. In addition, the flow rate control valve  60  thus constructed does not require an actuator, a control device or other such additional devices. This may lead to simplification of the fuel-feeding device  10 . 
   As previously described, the fuel jet path (the fuel jet conduit pipe  37 ) is branched from the fuel feeder path between the pump portion  27  of the fuel pump  16  and the pressure regulator  20  via the branching portion (the second outlet port  36 ) that is positioned upstream of the first outlet port  35 . That is, the fuel feeder path squeezing portion (the squeezing portion  41  of the pressure holding valve  40 ) is positioned downstream of the branching portion (the second outlet port  36 ) in the fuel feeder path. The fuel feeder path squeezing portion thus positioned may preferably contribute to increasing a pressure of the liquid fuel in the fuel jet conduit pipe  37  as well as the pressure (the upstream fuel pressure P 2 ) of the liquid fuel in upstream of the fuel feeder path squeezing portion in the fuel feeder path. Therefore, the fuel liquid in the fuel jet conduit pipe  37  can flow toward the jet pump  22  at an increased flow speed. 
   Further, in this embodiment, the fuel feeder path squeezing portion is composed of the squeezing portion  41  of the pressure holding valve  40 . Therefore, the fuel-feeding device  10  can be structurally simplified. 
   In addition, the fuel jet path (the fuel jet conduit pipe  37 ) is branched from the fuel feeder path via the branching portion (the second outlet port  36 ) that is positioned in parallel with the first outlet port  35 . Therefore, in comparison with a case in which the fuel jet path (the fuel jet conduit pipe  37 ) is branched from the fuel feeder path via the pressure regulator  20 , the bore size of the nozzle  55  of the jet pump  22  can be reduced regardless of a back pressure. As a result, the jet pump  22  may have an increased efficiency. 
   Second Embodiment 
   The second detailed representative embodiment will now described with reference to  FIGS. 3 to 5 . 
   Because the second embodiment relates to the first embodiment, only the constructions and elements that are different from the first embodiment will be explained in detail. Elements that are the same in the first and second embodiments will be identified by the same reference numerals and a detailed description of such elements may be omitted. 
   In a fuel-feeding device  110  of this embodiment, as shown in  FIG. 3 , the second outlet port  36  in the first embodiment is omitted. Instead, the vapor jet port  38  communicates with the jet pump  22  via the fuel jet conduit pipe  37 . That is, the fuel jet path (the fuel jet conduit pipe  37 ) is substantially branched from the pump cavity  30  (a portion of the fuel feeder path) of the fuel pump  16 . Further, in this embodiment, the vapor jet port  38  constitutes the branching portion of the fuel jet path. 
   Further, as shown in  FIG. 4 , a flow rate control valve  160  corresponding to the flow rate control valve  60  of the first embodiment is disposed in the vapor jet port  38  and not in the fuel jet conduit pipe  37 . In particular, the flow rate control valve  160  may preferably be fitted into a recessed portion  66  formed in the pump housing  28  of the fuel pump  16 . Further, the recessed portion  66  may preferably be formed so as to be axially aligned with the vapor jet port  38 . 
   As best shown in  FIG. 5 , the flow rate control valve  160  may preferably be composed of a cylindrical valve housing  170  having an axial through bore  170   a  formed therein, a valve body  162 , a spring (coil spring)  163 , and a spring stopper  164  secured to a lower end of the through bore  170   a . The through bore  170   a  may preferably be arranged so as to be aligned with the vapor jet port  38  ( FIG. 4 ). Further, an upper (upstream) end portion of the through bore  170   a  is upwardly tapered, so that a valve seat  161  is integrally formed in the valve housing  170 . The valve body  162  is disposed in the through bore  170   a  so as to move toward and away from the valve seat  161 . The coil spring  163  is positioned between the valve body  162  and the spring stopper  164 , so as to normally bias the valve body  162  toward the valve seat  161  (toward upwardly in  FIGS. 4 and 5 ). As will be appreciated, the moving distance of the valve body  162  can be changed depending upon the pumping pressure of the fuel pump  16 , so that a valve opening area of the flow rate control valve  160  (which area corresponds to an opening area of the fuel jet pipe  37 ) can be changed. Thus, similar to the flow rate control valve  60  of the first embodiment, the flow rate control valve  160  may preferably function as a pressure-dependent variable valve. 
   As best shown in  FIG. 5 , the valve body  162  is formed in one piece and is composed of an upper valve head  162   a  and a lower valve stem  162   b . The valve head  162   a  may preferably be hemispherically-shaped so as to be capable of closely contacting the valve seat  161 . Conversely, the valve stem  162   b  may preferably be shaped so as to be coupled to the coil spring  163 . Further, a through bore (a vapor relief bore)  162   c  may preferably be formed in the valve body  162  so as to longitudinally extend along the valve body  162 . 
   As shown in  FIG. 4 , the flow rate control valve  160  thus constructed may preferably be fitted into the recessed portion  66  formed in the pump housing  28  of the fuel pump  16  via a cylindrical outer cushioning shell  172  that circumferentially encircles the valve housing  170 . 
   As indicated by solid lines in  FIG. 5 , when the flow rate (the pumping rate PQ) of the liquid fuel pumped from the fuel pump  16  is low (i.e., when the pumping pressure of the fuel pump  16  is low), the valve body  162  (the valve head  162   a ) can contact the valve seat  161 , so that the flow rate control valve  160  can be substantially closed. Conversely, as indicated by broken lines in  FIG. 5 , when the flow rate (the pumping rate PQ) of the liquid fuel pumped from the fuel pump  16  is high (i.e., when the pumping pressure of the fuel pump  16  is high), the valve body  162  (the valve head  162   a ) can be spaced away from the valve seat  161  against a spring force of the coil spring  163 , so that the flow rate control valve  160  can be opened. Further, even if the flow rate control valve  160  is closed, the vapor-containing liquid fuel can be effectively discharged via the through bore  162   c  formed in the valve body  162 . 
   The fuel-feeding device  110  thus constructed may substantially have the same functions and effects as the fuel-feeding device  10  of the first embodiment. Further, in this embodiment, the fuel jet path (the fuel jet conduit pipe  37 ) is branched from the pump cavity  30  of the fuel pump  16  via the vapor jet port  38 . Therefore, the liquid fuel pressurized in the pump cavity  30  can be fed to the jet pump  22  via the fuel jet conduit pipe  37 , so that the jet pump  22  can be actuated. In addition, the liquid fuel pressurized in the pump cavity  30  can be easily fed to the jet pump  22  via the fuel jet conduit pipe  37 . 
   Further, the second embodiment can be modified. For example, an additional port (the relief port)  68  communicating, with the pump cavity  30  can be formed in the pump housing  28 . In the modified form, instead of the vapor jet port  38 , the additional port  68  communicates with the jet pump  22  via the fuel jet conduit pipe  37 . The additional port  68  may preferably be formed in the pump housing  28  so as to be juxtaposed to the vapor jet port  38 . Generally, the additional port  68  may preferably be positioned downstream of the vapor jet port  38 . Naturally, the recessed portion  66  may preferably be formed so as to be axially aligned with the additional port  68 . Further, in the modified form, as shown in  FIG. 6 , the through bore  162   c  formed in the valve body  162  can be omitted. 
   In the modified form, similar to the second embodiment, the liquid fuel pressurized in the pump cavity  30  can be fed to the jet pump  22  via the fuel jet conduit pipe  37 , so that the jet pump  22  can be actuated. 
   Further, the flow rate control valve  160  can be modified. For example, as shown in  FIG. 7 , the valve body  162  can be changed to a spherically-shaped valve body  262   
   Naturally, various changes and modifications may be made to the fuel-feeding device  10  and  110 . For example, the position of the flow rate control valve  60  and  160  can be changed in the fuel feeder path, if necessary. Further, an electrically controlled valve can be used as the flow rate control valve  60  and  160 . Further, the position of the jet pump  22  can be changed provided that the liquid fuel in the fuel tank  12  can be introduced into the reservoir cup  14 . In addition, the fuel tank  12  may be a saddle-shaped tank having a main tank and a secondary tank. In such a case, the jet pump  22  may preferably be arranged so as to transfer the liquid fuel in the secondary tank to the main tank. Further, in the embodiments, although the fuel feeder path squeezing portion is formed in the pressure holding valve  40 , the fuel feeder path squeezing portion can be formed separately from the pressure holding valve  40 . 
   Representative examples of the present invention have been described in detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present invention and is not intended to limit the scope of the invention. Only the claims define the scope of the claimed invention. Therefore, combinations of features and steps disclosed in the foregoing detail description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe detailed representative examples of the invention. Moreover, the various features taught in this specification may be combined in ways that are not specifically enumerated in order to obtain additional useful embodiments of the present invention.