Fuel supply system

Abstract

A fuel supply system supplies fuel in a fuel tank to a fuel consumption apparatus. The system includes a subtank, a pump unit, and an urging device. The subtank is received in the fuel tank and has a communicating hole at a bottom of the subtank. Part of fuel, which is stored in the fuel tank, is stored in the subtank. The outside and inside of the subtank communicate through the hole. The pump unit is received in the subtank and has a supply pump part, which supplies fuel in the subtank to the apparatus, and a pumping part, which pumps up fuel outside the subtank into the subtank. The pumping part has a suction part, which suctions fuel outside the subtank through the hole. The urging device urges the pump unit directly or indirectly toward the bottom of the subtank.

1 . A fuel supply system that is configured to supply fuel in a fuel tank to a fuel consumption apparatus, the system comprising:
 a subtank that is received in the fuel tank and has a communicating hole at a bottom of the subtank, wherein:
 a part of fuel, which is stored in the fuel tank, is stored in the subtank; and 
 an outside and an inside of the subtank communicate through the communicating hole; 
   a pump unit received in the subtank and having a supply pump part, which supplies fuel in the subtank to the fuel consumption apparatus, and a pumping part, which pumps up fuel outside the subtank into the subtank, wherein the pumping part has a suction part, which suctions fuel outside the subtank through the communicating hole; and   an urging means for urging the pump unit one of directly and indirectly toward the bottom of the subtank.   
   
   
       2 . The fuel supply system according to  claim 1 , wherein the suction part has a fitted part, which is fitted into the communicating hole of the subtank. 
   
   
       3 . The fuel supply system according to  claim 2 , wherein the urging means includes:
 a lid member that closes an opening formed on a ceiling portion of the fuel tank in a vertical direction thereof;   a projection portion formed one of directly and indirectly on the pump unit to project in a radial direction of the pump unit; and   an urging member that is held by the lid member at one end of the urging member and is held by the projection portion at the other end of the urging member, wherein the urging member urges the pump unit one of directly and indirectly toward the bottom of the subtank.   
   
   
       4 . The fuel supply system according to  claim 3 , wherein:
 the lid member includes a shaft extending toward a bottom of the fuel tank; and   the projection portion includes a guiding portion that holds a side surface of the shaft and that guides the pump unit in an axial direction of the shaft.   
   
   
       5 . The fuel supply system according to  claim 4 , further comprising a shaft supporting part at a lateral bottom end portion of the pump unit in a vertical direction thereof, wherein the shaft supporting part supports the shaft on an extension line of the shaft. 
   
   
       6 . The fuel supply system according to  claim 1 , wherein:
 the urging means includes a main body part that supports the pump unit one of directly and indirectly; and   the main body part has an engagement part, which engages the subtank, and an urging part, which urges the pump unit one of directly and indirectly toward the bottom of the subtank.   
   
   
       7 . The fuel supply system according to  claim 6 , wherein the urging part has a shape of a plate, and the urging part is configured to bend so as to urge the pump unit. 
   
   
       8 . The fuel supply system according to  claim 6 , wherein the urging part is a coil spring. 
   
   
       9 . The fuel supply system according to  claim 6 , wherein the suction part has a fitted part, which is fitted into the communicating hole of the subtank. 
   
   
       10 . The fuel supply system according to  claim 6 , wherein:
 the subtank opens on an opposite side of the bottom of the subtank;   the engagement part of the urging means is fitted on the subtank in a direction from an opening side toward the bottom of the subtank, so that the engagement part engages the subtank; and   the urging part of the urging means urges an end portion of the pump unit, which is on the opening side of the subtank, one of directly and indirectly toward the bottom of the subtank.   
   
   
       11 . The fuel supply system according to  claim 1 , wherein the pump unit further includes:
 an impeller having an outer circumference side vane part on an outer circumferential side of the impeller, and an inner circumference side vane part on an inner circumferential side of the impeller;   a passage member having an outer circumference side pump passage, which is formed in a shape of a circular arc along the outer circumference side vane part, and an inner circumference side pump passage, which is formed in a shape of a circular arc along the inner circumference side vane part; and   an electric motor part configured to drive the impeller to rotate, wherein the supply pump part includes the outer circumference side vane part and the outer circumference side pump passage, and the pumping part includes the inner circumference side vane part and the inner circumference side pump passage.   
   
   
       12 . The fuel supply system according to  claim 1 , wherein the suction part includes:
 a case having therein a partition wall, which defines a supply fuel passage and a pumping fuel passage, wherein:
 an inlet of the supply fuel passage opens in the subtank, and an outlet of the supply fuel passage is connected to the supply pump part; and 
 an inlet of the pumping fuel passage opens outside the subtank through the communicating hole, and an outlet of the pumping fuel passage is connected to the pumping part; 
   a supply fuel filter disposed in the supply fuel passage; and   a pumping fuel filter disposed in the pumping fuel passage.   
   
   
       13 . The fuel supply system according to  claim 1 , wherein:
 the subtank has a guiding portion on an inner wall surface of the subtank; and   the guiding portion guides the suction part into the communicating hole.   
   
   
       14 . The fuel supply system according to  claim 1 , wherein:
 the subtank is formed in a cylindrical shape having a bottom portion, and opens at an upper portion of the subtank in a vertical direction thereof;   the suction part has a lower opening part, through which fuel outside the subtank is suctioned by the pumping part, at an end portion of the pump unit that is opposed to the bottom of the subtank;   the pump unit has a discharge opening, through which fuel suctioned through the lower opening part is discharged into the subtank by the pumping part at the end portion of the pump unit;   the lower opening part penetrates through the communicating hole such that the lower opening part projects from the bottom of the subtank into the outside of the subtank; and   the fuel supply system further comprising:
 a guided portion on a side portion of the pump unit, wherein the guided portion projects in a radial direction of the pump unit; and 
 a guiding portion on a side wall of the subtank, wherein the guiding portion is arranged to guide the guided portion such that, when the pump unit is inserted in the subtank in a direction from an opening side toward the bottom of the subtank, the lower opening part is conducted into the communicating hole. 
   
   
   
       15 . The fuel supply system according to  claim 14 , wherein:
 the fuel tank has an opening, through which the subtank and the pump unit are inserted in the fuel tank, on an upper wall of the fuel tank in a vertical direction thereof;   the fuel supply system further comprising;
 a lid member that blocks the opening; and 
 a shaft that extends from the lid member toward the bottom of the subtank and that connects the lid member and the pump unit; and 
   the guided portion includes a supporting part, which supports the shaft.   
   
   
       16 . The fuel supply system according to  claim 14 , wherein:
 the pump unit includes:
 a fuel pump portion having the pumping part; and 
 the suction part disposed at an end portion of the fuel pump portion and having a filter element, which filters fuel suctioned through the lower opening part, and a case, which has the lower opening part at one end portion of the case; and 
   the guided portion is formed on a side portion of the case.   
   
   
       17 . The fuel supply system according to  claim 14 , wherein:
 the guided portion includes a first guided portion and a second guided portion; and   the first guided portion and the second guided portion are formed on the side portion of the pump unit along a direction in which the pump unit is inserted in the subtank.   
   
   
       18 . The fuel supply system according to  claim 17 , wherein:
 the fuel tank has an opening, through which the subtank and the pump unit are inserted in the fuel tank, on an upper wall of the fuel tank in a vertical direction thereof;   the fuel supply system further comprising:
 a lid member that blocks the opening; and 
 a shaft that extends from the lid member toward the bottom of the subtank and that connects the lid member and the pump unit; 
   the first guided portion includes a supporting part, which supports the shaft; and   the second guided portion is formed below the first guided portion.   
   
   
       19 . The fuel supply system according to  claim 18 , wherein:
 the pump unit includes:
 a fuel pump portion having the pumping part; and 
 the suction part disposed at an end portion of the fuel pump portion and having a filter element, which filters fuel suctioned through the lower opening part, and a case, which has the lower opening part at one end portion of the case; 
   the shaft penetrates through the supporting part of the first guided portion; and   the second guided portion is located such that, when the shaft is pushed in toward the bottom of the subtank, a leading end of the shaft, which has penetrated through the supporting part, reaches the second guided portion.   
   
   
       20 . The fuel supply system according to  claim 14 , wherein the guided portion is formed on a guiding member, which is attached to the pump unit and is different from the pump unit.