Patent Publication Number: US-2007113830-A1

Title: In-line type fuel supply device in fuel injection device

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a fuel injection device, in which fuel in a fuel tank is increased in pressure by a fuel pump, the fuel increased in pressure is regulated in pressure by a pressure regulator, and the fuel regulated in pressure is supplied toward a fuel injection valve. More particularly, the present invention relates to an in-line type fuel supply device, in which a fuel pump is provided at the outside of the fuel tank, and is provided in a fuel pipe for connecting the fuel tank and the fuel injection valve.  
      2. Description of the Conventional Art  
      A conventional in-line type fuel supply device is illustrated in  FIG. 2 .  
      Reference numeral  30  is a pump case formed in a sealing state by a lower case body  31  and an upper case body  32 . A fuel intake passage  33  is opened at a lower end of the pump case  30 , and a pump discharge passage  34  is opened at an upper end of the pump case  30 .  
      A fuel pump P comprises a Westco type pump portion  36  having an impeller  35  and a motor portion  37  for rotating the impeller  35 , and is provided in a cylindrical casing K. Further, a pump intake passage  38  connected with the pump portion  36  is opened toward a lower end in the right side of  FIG. 2 , and a pump discharge passage  39  is opened in a protruding manner toward an upper end in the left side of  FIG. 2 .  
      The fuel pump P is inserted and supported in the pump case  30  by a first support member  40  in the right side and a second support member  41  in the left side, where the first support member  40  has a pressing support piece portion  40   a  for pressing an outer circumference of the casing K. At this time, a cylindrical space  42  is formed between the casing K forming an outer circumference of the fuel pump P and an inner circumference of the pump case  30 .  
      Further, the pump intake passage  38  of the fuel pump P is connected into a fuel flow-in chamber  44 , which is formed at a right end of the pump case  30 , through a filter  43 , and the pump discharge passage  39  is inserted and supported in a pump discharge passage support hole  45  of the second support member  41 . The pump discharge passage support hole  45  is connected to a fuel discharge passage  34 , which is opened at a left end of the pump case  30 , through a fuel flow-out chamber  46  formed at the left end of the pump case  30 .  
      In addition, the cylindrical space  42  and the fuel flow-out chamber  46  are shut off by the second support member, and the fuel intake passage is opened in the fuel flow-in chamber  44 . Further, reference numeral  47  is a fuel return passage connected to the cylindrical space  42 .  
      Reference symbol R is a pressure regulator, and has the following structure.  
      Reference numeral  50  is a sectioning body held by a first casing body  51  and a second casing body  52 . A fuel chamber  53  is formed with a right side surface of the sectioning body  50  and a recessed portion of the first casing body  51 , and pressure chamber  54  is dividedly formed with a left side surface of the sectioning body  50  and a recessed portion of the second casing body  52 .  
      Further, a regulator fuel flow-in hole  55  and a regulator fuel control hole  56  are opened in the fuel chamber  53 , and a control valve  57  is provided facing to an opening end of the regulator fuel control hole toward the inside of the fuel chamber  53 , where the control valve  57  is moved synchronously with the sectioning body  50 .  
      Further, reference numeral  58  is a spring provided in contraction in the pressure chamber  54 , and the sectioning body  50  including the control valve  57  is energized on the fuel chamber  53  side by the spring  58 .  
      Further, the regulator fuel flow-in hole  55  is connected to the fuel flow-out chamber  46  of the pump case  30 , and the regulator fuel control hole  56  is connected to the cylindrical space  42  of the pump case  30 .  
      Further, a pressure pipe  59  opened on the pressure chamber  54  is connected to, for example, an intake passage on the downstream side from a throttle valve of a throttle body which is not illustrated in the drawings.  
      Further, the pump case  30  comprising the pressure regulator R and the fuel pump P is provided at the outside of the fuel tank, and connected by piping as follows.  
      The fuel intake passage  33  is connected with a fuel tank T by a first fuel pipe  60 .  
      The fuel discharge passage  34  is connected toward a fuel injection valve J by a second fuel pipe  61 .  
      Further, the fuel return passage  47  is connected with the fuel tank T by a third fuel pipe  62 .  
      As described above, the fuel stored in the fuel tank T is supplied in the fuel flow-in chamber  44  through the first fuel pipe  60 , to thereby fill the fuel flow-in chamber  44  with the fuel.  
      On the other hand, when the fuel pump P is driven, the fuel in the fuel flow-in chamber  44  is sucked to the pump portion  36  comprising the impeller  35  through a filter  43  and the pump intake passage  38 , and increased in pressure by the pump portion  36 . Then, the fuel increased in pressure passes through a motor space M between the outer circumference of the motor portion  37  and the inner circumference of the casing K, reaches the pump discharge passage  39 , and is discharged to the fuel flow-out chamber  46  through the pump discharge passage support hole  45  of the second support member  41 .  
      In this case, the fuel supplied into the fuel flow-out chamber  46  is supplied into the fuel chamber  53  through the regulator fuel flow-in hole  55 . Further, the fuel filled in the fuel chamber  53  moves the control valve  57  to the left in the drawings through the sectioning body  50 , is balanced with the spring  58  by a set pressure, and then, the opening of the regulator fuel control hole  56  is controlled by the control valve  57 .  
      Thereby, the fuel in the fuel flow-out chamber  46  is controlled to be a predetermined fuel pressure.  
      Therefore, the fuel having the predetermined fuel pressure in the fuel flow-out chamber  46  can be supplied to the fuel injection valve J through the fuel discharge passage  34  of the pump case  30  and the second fuel pipe  61 .  
      On the other hand, the fuel flowing in the regulator fuel control hole  56  is discharged into the cylindrical space  42  of the pump case  30 , and the discharged fuel is flowed back to the fuel tank T through the fuel return passage  47  and the third fuel pipe  62 .  
     SUMMARY OF THE INVENTION  
      According to such the in-line type fuel supply device, the fuel increased in pressure by the pump portion  36  passes through the motor space M, and is supplied into the fuel chamber  53  of the pressure regulator R through the pump discharge passage  39 , the pump discharge passage support hole  45  and the fuel flow-out chamber  46 . Further, the fuel in the fuel chamber  53  is supplied into the cylindrical space  42  of the pump case  30  from the regulator fuel control hole  56 . Furthermore, the fuel in the cylindrical space  42  is returned into the fuel tank T through the fuel return passage  47  and the third fuel pipe  62 .  
      According to the above-described structure, the fuel flowing in the motor space M cools the outer circumference of the motor portion  37  of the fuel pump P to thereby control increasing of the temperature of the motor portion  37 . Thereby, the fuel having absorbed the heat of the motor portion  37  to have a high temperature flows into the fuel chamber  53  of the pressureregulatorRfromthefuel flow-out chamber  46 , and flows into the cylindrical space  42  through the regulator fuel control hole  56 .  
      According to the above-described structure, the fuel having a high temperature flows into cylindrical space  42  between the outer circumference of the casing K and the inner circumference of the pump case  30 , where the cylindrical space  42  is small. Thereby,much vapor is generated in the cylindrical space  42 .  
      Further, much of the fuel including the vapor are returned to the fuel tank T through the fuel return passage  47  and the third fuel pipe  62 . However, when the pump intake passage  38  and the cylindrical space  42  are not accurately maintained airtight by the first support member  40 , a part of the vapor flowing in the cylindrical space  42  may be re-sucked to the pump portion  36  through the pump intake passage  38 . Thereby, the pressure of the fuel discharged from the pump portion  36  cannot be increased enough. Further, the fuel supply becomes intermittent, so that there is a problem that a continuous and smooth fuel supply cannot be carried out.  
      Further, as illustrated in  FIG. 2 , the vapor maybe mixed into the fuel supplied from the fuel tank T to the fuel flow-in chamber  44 , then the vapor stored in the fuel flow-in chamber  44  is often discharged into the cylindrical space  42  through a vapor discharge passage  65 . However, the vapor produced in the cylindrical space  42  is eventually sucked into the fuel flow-in chamber  44  being in a negative pressure state, and the vapor is re-sucked to the pump portion  36 , so that there is the same problem as described above.  
      Further, in this structure, the high temperature fuel having absorbed the heat of the motor portion  37  once flows at the outer circumference of the casing K of the fuel pump P, that is, in the cylindrical space  42 , so that it is hard to effectively cool the motor portion  37 . More particularly, in the in-line type fuel supply device, it is required that the fuel pump is provided very far from the heating part such as an engine or the like, or provided at a position easily receiving a travel wind, so that freedom of location of the fuel pump is limited.  
      The present invention solves the above-described problems, and an objective of the present invention is to provide an in-line type fuel supply device in a fuel injection device, in which vapor which is generated in a cylindrical space by regulator fuel returned from a regulator fuel control hole of a pressure regulator to a fuel tank, is not re-sucked to a pump portion of a fuel pump, to thereby enhance pump ability of the fuel pump, a motor portion of the fuel pump can be effectively cooled, to thereby enhance motor efficiency, further, vapor stored in a pump case is effectively discharged, and, furthermore, freedom of location of the fuel pump in the in-line type fuel supply device can be enhanced.  
      In one aspect of the in-line type fuel supply device in the fuel injection device of the present invention in order to obtain the above-described objective, the fuel supply device in the fuel injection device, in which the fuel in a fuel tank is increased in pressure by a fuel pump provided at the outside of the fuel tank, regulated in pressure at a predetermined fuel pressure by a pressure regulator, and supplied toward a fuel injection valve, is structured such that, the fuel pump is supported in a pump case surrounding an outer circumference of the fuel pump in such a manner as to have a cylindrical space, a pump intake passage of the fuel pump is provided and opened at a fuel flow-in chamber, which is formed at a lower end of the pump case, through a filter, a pump discharge passage of the fuel pump is inserted and connected to a fuel discharge passage formed at an upper end of the pump case, and a vapor discharge hole is opened at an upper space of the pump case connecting to the cylindrical space, that the pressure regulator is divided to a fuel chamber and a pressure chamber by a sectioning body, a regulator fuel flow-in hole and a regulator fuel control hole are opened in the fuel chamber, and a control valve for controlling the opening of the regulator fuel control hole is integrally provided at the sectioning body, and that the fuel discharge passage of the pump case is connected toward the fuel injection valve with a first fuel pipe, a second fuel pipe branched from the first fuel pipe is connected to the regulator fuel flow-in passage of the pressure regulator, the regulator fuel control hole is connected and opened in the fuel tank with a third fuel pipe, and the vapor discharge hole of the pump case is connected and opened in the fuel tank with a fourth fuel pipe.  
      Further, in another aspect of the present invention, in addition to the above-described aspect, a longitudinal axial line X-X of the fuel pump is provided to be inclined at an angle A of 45° or more upwardly with respect to a horizontal line Y-Y in the gravitational direction, and the vapor discharge hole is opened at an upper position in the gravitational direction than an upper space.  
      According to the one aspect of the present invention, the fuel in the fuel tank is supplied into the fuel flow-in chamber of the pump case through the fuel flow-in pipe, and the fuel in the fuel flow-in chamber is sucked to the pump portion of the fuel pump from the pump intake passage through the filter.  
      The fuel increased in pressure by the pump portion passes through the outer circumference of the motor portion, and is supplied to the fuel injection valve through the pump discharge passage, the fuel discharge passage and the first fuel pipe.  
      In this case, a part of the fuel flowing in the first fuel pipe is supplied into the fuel chamber of the pressure regulator through the second fuel pipe and the regulator fuel flow-in passage, and this fuel is regulated in pressure to a predetermined fixed fuel pressure. Thereby, the fuel regulated in pressure can be supplied from the first fuel pipe to the fuel injection valve.  
      On the other hand, surplus fuel generated by a pressure regulating action of the pressure regulator is discharged into the fuel tank through the regulator fuel control hole and the third fuel pipe.  
      As described above, when the fuel increased in pressure by the pump portion of the fuel pump passes through the motor portion, the fuel absorbs the heat produced at the motor portion to thereby increase the fuel temperature. However, the fuel having the increased temperature is supplied to the fuel injection valve through the first fuel pipe and further, returned to the fuel tank through the second fuel pipe, the pressure regulator, the regulator fuel control hole and the third fuel pipe. Thus, the fuel having the increased temperature is not directly re-supplied to the fuel pump.  
      Therefore, the motor portion of the fuel pump can be effectively cooled, to thereby enhance the motor efficiency.  
      Further, since the motor portion is effectively cooled, the fuel pump can be provided near the engine, so that the freedom of location of the fuel pump in the in-line type fuel supply device can be enhanced especially.  
      Further, the vapor may be mixed into the fuel flowing into the fuel flow-in chamber from the fuel tank through the fuel flow-in pipe. However, the vapor in the fuel flow-in chamber flows into the cylindrical space, and the vapor in the cylindrical space is discharged into the fuel tank through the upper space of the pump case, the vapor discharge hole and the forth fuel pipe. Thus, the vapor in the fuel flow-in chamber is not sucked to the pump portion of the fuel pump, the fuel can be accurately increased in pressure by the pump portion, and the fuel can be supplied continuously and smoothly.  
      Further, in the in-line type fuel supply device, since the fuel flows into the cylindrical space from the fuel flow-in chamber, the fuel in the cylindrical space receives the heat of the fuel pump, so that the vapor may be generated in the cylindrical space. However, the vapor generated in the cylindrical space is also discharged into the fuel tank through the fourth fuel pipe like the above-description. Thus, the vapor is not filled in the cylindrical space, and is not sucked to the pump portion of the fuel pump from the pump intake passage.  
      Further, according to the other aspect of the present invention, the fuel pump is provided to be inclined at an angle of 45° or more upwardly with respect to the horizontal line, and the vapor discharge hole is opened an the upper position in the gravitational direction than the upper space of the pump case. There by, vapor in the cylindrical space can be accurately collected in the upper space of the pump case, and the vapor can be accurately discharged from the forth fuel pipe to the fuel tank. Thus, discharge ability of the vapor in the cylindrical space can be enhanced, and the vapor in the cylindrical space is not sucked further into the fuel pump. 
    
    
     BRIEF EXPLANATION OF DRAWINGS  
       FIG. 1  is a longitudinal sectional view illustrating one example of an in-line type fuel supply device in a fuel injection device of the present invention.  
       FIG. 2  is a longitudinal sectional view illustrating a conventional in-line type fuel supply device in a fuel injection device. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT  
      Hereinafter, one example of the in-line type fuel supply device in the fuel injection device according to the present invention will be described with drawings.  
      In this case, structures of a fuel pump and a pressure regulator used in  FIG. 1  are same as those of  FIG. 2 , so that same reference numerals and symbols are used to thereby omit descriptions.  
      Reference numeral  1  is a pump case formed in a sealing state by a lower case body  2  and an upper case body  3 . The lower case body  2  has a bottomed cylindrical shape having an opening upper portion, and the upper case body  3  has a bottomed cylindrical shape having an opening lower portion. Flange portions of both opening portions are contacted and provided.  
      A fuel pump P is held by a first support body  4  and a second support body  5  between a locking step portion  2   a  and a locking step portion  3   a , where the locking step portion  2   a  faces to an upper part of the lower case body  2 , and the locking step portion  3   a  faces to a lower part of the upper case body  3 . At this time, a lower portion Pa of the fuel pump P having a pump intake passage  38  of the fuel pump P is provided so as to face to a fuel flow-in chamber  6  formed at a lower bottom portion  2   b  of the lower case body  2 . An upper portion Pb of the fuel pump P is provided so as to face to an upper space  7  formed at an upper bottom portion  3   b  of the upper case body  3 .  
      Further, the pump intake passage  38  of the fuel pump is connected into the fuel flow-in chamber  6  through a filter  43 , and a pump discharge passage  39  projected upwardly from the upper portion Pb of the fuel pump P is inserted and connected to a fuel discharge passage  8  which is provided and opened downwardly in the upper case body  3 .  
      Further, a cylindrical space  9  is continuously formed between the outer circumference of a casing K of the fuel pump P and the inner circumference of the lower case body  2 . A lower part of the cylindrical space  9  is connected into the fuel flow-in chamber  6 , and an upperpart of the cylindrical space  9  is connected to the upper space  7 . Further, a vapor discharge hole  10  is opened on the upper bottom portion  3   b  of the upper case body  3  toward the upper space  7 .  
      That is, the fuel flow-in chamber  6  is connected to the upper space  7  through the cylindrical space  9 .  
      Further, the fuel intake passage  11  is opened in the fuel flow-in chamber  6  of the pump case  1 , and the fuel intake passage  11  is connected to a bottom portion of the fuel tank T through the fuel flow-in pipe  12 .  
      Further, the fuel discharge passage  8  is connected to the fuel injection valve J through a first fuel pipe  13 .  
      Further, a regulator fuel flow-in hole  55  of a pressure regulator R is connected to a second fuel pipe  14  branched from the first fuel pipe  13 , and a regulator fuel control hole  56  is connected to the fuel tank T through a third fuel pipe  15 .  
      Furthermore, a vapor discharge hole  10  is opened and connected to the upper portion of the fuel tank T through a forth fuel pipe  16 .  
      According to the above-described structure, the fuel in the fuel tank T is supplied toward the fuel flow-in chamber  6  of the pump case  1  through the fuel flow-in pipe  12 , where the fuel flow-in chamber  6  is provided at a position being lower than the fuel tank T. The fuel stored in the fuel flow-in chamber  6  is sucked to a pump portion  36  through the filter  43  and the pump intake passage  38 , and the fuel increased in pressure by the pump portion  36  passes through the outer circumference of a motor portion  37 , and is supplied toward the fuel injection valve J through the pump discharge passage  39 , the fuel discharge passage  8  and the first fuel pipe  13 .  
      On the other hand, a part of the fuel flowing in the first fuel pipe  13  is supplied into the fuel chamber of the pressure regulator R through the second fuel pipe  14  and the regulator fuel flow-in hole  55 , and is regulated in pressure at a predetermined fixed fuel pressure by a control valve  57 .  
      Thereby, the pressure of the fuel flowing in the first fuel pipe  13  connected to the second fuel pipe  14  is also regulated at the predetermined fixed pressure, so that the fuel regulated in pressure is supplied to the fuel injection valve J through the first fuel pipe  13 .  
      On the other hand, the surplus fuel regulated in pressure by the control valve flows down in the regulator fuel control hole  56 , and is discharged into the fuel tank T through the third fuel pipe  15 .  
      Further, in the fuel flowing in the fuel flow-in pipe  12 , floating air and vapor are included, where the air is involved into the fuel by the vibration of the fuel tank T and the vapor is generated by the fuel flow-in pipe  12  heated by the surrounding. The vapor (including the air) maybe supplied into the fuel flow-in chamber  6  through the fuel flow-in pipe  12 . However, the vapor flows into the cylindrical space  9  from the fuel flow-in chamber  6  by a self buoyancy, and is discharged into the fuel tank T through the upper space  7 , the vapor discharge hole  10  and the fourth fuel pipe  16 .  
      Accordingly, when the fuel increased in pressure by the pump portion  36  of the fuel pump P passes through the motor portion  37 , the motor portion  37  is cooled, so that deterioration of rotation ability by increasing the temperature of the motor portion  37  can be prevented, and a pump ability can be sufficiently kept.  
      Further, in the pump portion  36 , the fuel heated by the motor portion  37  once is not returned to the motor portion  37 , and not contacted with the casing K of the motor portion  37  in contrast with the case of the conventional one. Thus, the temperature of the motor portion  37  is not remarkably increased and thus, a location to provide the fuel pump P is not limited. So, freedom of a location for the fuel pump P can be enhanced.  
      Further, since the casing K of the motor portion  37  is supplied with new fuel from the fuel tank T through the fuel flow-in pipe  12 , increasing of the temperature of the fuel pump Pitself including the motor portion  37  can be prevented. Thereby, generating of the vapor in the fuel pump P can be prevented, and mixing of the vapor into the fuel flowing toward the fuel injection valve J from the first fuel pipe  13  can be prevented. Thus, the stable fuel can be supplied continuously from the fuel injection valve J.  
      Further, when the fuel including the vapor is supplied into the fuel flow-in chamber  6  from the fuel flow-in pipe  12 , the vapor flows into the cylindrical space  9  immediately by the self buoyancy, so that the vapor is not stored in the fuel flow-in chamber  6 . Thus, the vapor is not sucked to the pump portion  36  of the fuel pump P, and the stable fuel can be supplied continuously into the first fuel pipe  13 .  
      On the other hand, the vapor flowing into the cylindrical space  9  flows into the upper space  7  immediately. The reason why the vapor flows into the upper space  7  immediately is that a cross-sectional area of the upper space  7  is larger than a cross-sectional area of the cylindrical space  9 , so that the vapor can be flowed into the upper space  7  without resistance.  
      Further, when the fuel in the cylindrical space  9  is heated by the fuel pump P to thereby generate the vapor in the cylindrical space  9 , the vapor flows into the upper space  7  like the above description.  
      Furthermore, a longitudinal axial line X-X of the fuel pump P is provided to be upwardly inclined at an angle A of 45° or more with respect to a horizontal line Y-Y in the gravitational direction, and an opening  10   a  of the vapor discharge hole  10  is opened at an upper position in the gravitational direction than the upper space  7 . Therefore, the vapor easily flows into the upper space  7  from the cylindrical space  9 , and the vapor flowing into the upper space  7  can be collected intensively in the upper space  7 . Furthermore, the vapor can be effectively discharged into the fourth fuel pipe  16 , to thereby more enhance the discharge ability of the vapor.  
      In addition, the first fuel pipe  13  can be connected to the regulator fuel flow-in hole  55  of the pressure regulator R, and the fuel chamber  53  and the fuel injection valve J can be connected with a fifth fuel pipe  18 . The fifth fuel pipe  18  is indicated by a dotted line in this drawing.