JP2008248803A - Pump unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable pump unit, in a pump unit disposed to a fuel tank having a plurality of fuel chambers, and transferring fuel from one fuel chamber to the other fuel chamber. <P>SOLUTION: The pump unit 1 transfers fuel from a second fuel chamber 94 to a first fuel chamber 91. The pump unit 1 comprises: a sub tank 3; an electric pump 5 pumping up the fuel in the sub tank 3; a housing chamber 7 disposed to a side wall of the sub tank 3 and storing the fuel; a jet pump 74 housed in the housing chamber 7, driven by the fuel supplied from the electric pump 5, connected with the second fuel chamber 94 by a transfer pipe 99, and transferring the fuel in the second fuel chamber 94 to the first fuel chamber 91; and a pressure regulation valve 8 regulating pressure supplied to the jet pump 74 by discharging part of the fuel supplied to the jet pump 74. The pressure regulation valve 8 has a discharge port 83 discharging the fuel, and the discharge port 83 is disposed to a bottom part 32 of the sub tank 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pump unit that transfers fuel from one fuel chamber of a fuel tank having a plurality of fuel chambers to the other fuel chamber.

A pump unit is known that is accommodated in a first fuel chamber of a fuel tank having a first fuel chamber and a second fuel chamber, and transfers the fuel in the second fuel chamber to the first fuel chamber (see Patent Document 1). . This pump unit includes a sub tank divided into a main chamber and a sub chamber by a partition wall, an electric pump housed in the main chamber and pumping fuel in the main chamber, and a fuel pumped by the electric pump housed in the sub chamber. And a jet pump that transfers the fuel in the second fuel chamber to the first fuel chamber using the negative pressure generated by the supply.
JP 2004-28054 A

  Here, one of the methods for controlling the transfer capacity of the pump unit is a pressure for adjusting the pressure in the passage by discharging excessive pressure discharged from the electric pump into the flow path between the electric pump and the jet pump. There is a method of controlling the negative pressure generated in the jet pump by providing a regulating valve. According to this method, the transfer capability can be controlled more easily than the method of controlling the transfer capability of the pump unit by controlling the electric power to the electric pump.

  However, in the pump unit of the type in which the electric pump and the jet pump are accommodated in the main chamber and the sub chamber, respectively, the flow path is provided so as to get over the partition wall that partitions the main chamber and the sub chamber. If a pressure regulating valve is provided in this flow path, the position of the pressure regulating valve will be disposed relatively upward. For this reason, when the liquid level of the fuel in the main chamber becomes low, the fuel discharged from the pressure regulating valve is struck against the fuel in the main chamber, the fuel bubbles, and bubbles are mixed into the fuel. When fuel containing bubbles is accumulated in the main chamber, the electric pump sucks the bubbles and cannot pump up the fuel, so that the fuel cannot be transferred from the second fuel chamber to the first fuel chamber. appear. In addition, if a pump that supplies fuel to the engine sucks bubbles in the main chamber, there is a risk that an appropriate amount of fuel cannot be supplied to the engine, or that the pump portion of the pump may burn out. .

  The present invention has been made in order to solve the above-described problem. In a pump unit that is provided in a fuel tank having a plurality of fuel chambers and transfers fuel in one fuel chamber to the other fuel chamber, the reliability is improved. The purpose is to provide a high pump unit.

  According to the first aspect of the present invention, the pump unit is accommodated in the first fuel chamber of the fuel tank having the first fuel chamber and the second fuel chamber, and transfers the fuel in the second fuel chamber to the first fuel chamber. A first container that accumulates fuel, an electric pump that is housed in the first container and pumps up the fuel in the first container, a second container that is provided on a side wall of the first container and accumulates fuel, A jet pump housed in a second container and driven by fuel pumped from an electric pump, connected to a second fuel chamber by a first connection pipe, and transfers fuel in the second fuel chamber to the first fuel chamber And a pressure regulating valve that regulates fuel pressure supplied to the jet pump by discharging part of the fuel supplied to the jet pump from the electric pump, and the pressure regulating valve is discharged Emissions that discharge fuel Has a discharge port is characterized in that it is arranged on the bottom of the first container.

  According to this configuration, since the discharge port of the pressure regulating valve is arranged at the bottom of the first container, the discharge port can be submerged in the fuel in the first container. As a result, even if the fuel is discharged from the discharge port, the discharged fuel is struck against the fuel in the first container, and the fuel does not foam. As a result, it is possible to suppress bubbles from being mixed into the fuel, and it is possible to suppress the occurrence of problems due to the suction of bubbles by an electric pump or a pump that supplies fuel to the engine.

  According to the second aspect of the present invention, there is provided a remaining amount measuring device that generates a signal corresponding to the remaining amount of fuel in the first fuel chamber, and the signal generated by the remaining amount measuring device is the fuel in the first fuel chamber. When the remaining amount is less than the predetermined remaining amount, the warning is transmitted to a warning device that issues a warning to the driver to refuel. The discharge port is the liquid in the first fuel chamber when the warning device generates a warning. It is characterized by being placed below the position.

  According to this configuration, since the discharge port is disposed below the liquid level in the first fuel chamber when the warning device generates a warning that prompts the driver to refuel, the discharge port is placed in the fuel. Can be placed. For this reason, even if the overpressure fuel is discharged from the discharge port, the fuel does not foam, and the bubbles can be prevented from being mixed into the fuel.

  According to invention of Claim 3, the electric pump has a suction filter in the bottom part side of the 1st container, and the discharge port is arrange | positioned so as to oppose the surface of a suction filter. It is said. According to this configuration, since the discharge port is arranged to face the surface of the suction filter of the electric pump, the electric pump can pump up using the jet of fuel discharged from the discharge port. For this reason, the efficiency of the electric pump is improved and the efficiency of the pump unit is also improved.

  According to the fourth aspect of the present invention, the first container is covered with a cover that supports the electric pump, and the cover is a second connection pipe that becomes a part of the passage between the electric pump and the jet pump. And a branch pipe branched from the second connection pipe and extending toward the bottom of the first container are integrally formed, and the pressure regulating valve is provided in the branch pipe.

  According to this configuration, the second connection pipe that supplies fuel to the jet pump to the cover that supports the electric pump and the branch pipe that branches from the second connection pipe and extends toward the bottom of the first container are integrally formed. Therefore, an increase in the number of parts can be suppressed.

  According to the fifth aspect of the present invention, the pressure regulating valve is provided at the bottom side end of the branch pipe, and has a main body having an inlet and an outlet connected to the branch pipe, and is accommodated in the main body. And a valve body for opening and closing the suction port. According to this configuration, the pressure regulating valve is provided at the bottom side end of the branch pipe, and the discharge port is formed in the main body portion of the pressure regulating valve, so there is some passage between the main body portion and the discharge port. The structure of the pump unit is simplified.

  According to the sixth aspect of the present invention, the pressure regulating valve is provided in the middle of the passage between the electric pump and the jet pump, and the pressure regulating valve is provided in the main body having a suction port connected to the passage, and the main body. It has a valve body that opens and closes the suction port, and a deformable hose portion that is connected to the main body and has a discharge port formed at the tip. According to this configuration, since the pressure regulating valve has the deformable hose portion that is connected to the main body portion and has a discharge port formed at the tip, the degree of freedom in disposing the discharge port in the first container. Will increase.

  Since the jet pump is accommodated in the second container, when the electric pump is stopped and a siphon phenomenon occurs, the fuel in the second container flows backward to the second fuel chamber via the first connection pipe. This reverse flow continues until the liquid level of the fuel in the second container is lowered and the first connection pipe is in an atmospheric pressure state. When the upper end of the second container is below the fuel level in the first fuel chamber, the fuel in the first fuel chamber always flows into the second container. That is, the fuel flows backward as long as the fuel flows into the second container.

  According to the seventh aspect of the present invention, the height of the upper end portion of the second container from the bottom portion of the first container is higher than the upper end portion of the first container. According to this configuration, since the upper end portion of the second container is located higher than the upper end portion of the first container, the inflow of fuel into the second container Compared to the case where the position is lower than the upper end, the vehicle stops earlier. As a result, the backflow of fuel can be stopped as soon as possible, and the amount of fuel backflowing through the first connection pipe can be suppressed.

  When the fuel in the second fuel chamber is low, the jet pump may inhale air. Since this air is ejected from the jet pump, the fuel in the second container is bubbled and bubbles are mixed into the fuel. Since the upper end portion of the second container is located higher than the upper end portion of the first container, there is a possibility that bubbles mixed in the fuel overflow from the second container and flow into the adjacent first container. When bubbles flow into the first container, the electric pump or the pump that supplies fuel to the engine cannot suck the bubbles and pump up the fuel.

  On the other hand, according to the invention described in claim 8, a notch portion is formed in the upper end portion of the second container opposite to the first container. According to this configuration, the fuel in which bubbles are mixed in the second container can be forcibly discharged to the opposite side of the first container through the notch. As a result, air bubbles can be prevented from flowing into the first container, and an electric pump or a pump that supplies fuel to the engine can be prevented from sucking air bubbles.

  According to invention of Claim 9, the height from the bottom part of the 1st container of the lower end part of a notch part is characterized by being higher than the upper end part of a 1st container. According to this structure, since the lower end part of a notch part is in a position higher than the upper end part of a 1st container, when the electric pump is stopped, the quantity of the fuel which flows back through 1st connection piping can be suppressed.

  Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
FIG. 1 shows a schematic configuration of a fuel supply system that supplies fuel (light oil) in a fuel tank to a diesel engine (hereinafter simply referred to as an engine). The fuel supply system includes a fuel tank 9 having an independent first fuel chamber 91 and a second fuel chamber 94, and a pump unit 1 that transfers fuel in the second fuel chamber 94 to the first fuel chamber 91. .

  The first fuel chamber 91 is provided with a fuel supply pipe 95 that supplies fuel to the engine 100 and a return pipe 97 that returns fuel that has not been used in the engine 100 to the first fuel chamber 91. A main suction filter 96 is provided at the end of the fuel supply pipe 95, and a pump 101 that sucks and pressurizes the fuel in the first fuel chamber 91 is provided in the middle of the fuel supply pipe 95.

  In the first fuel chamber 91, the pump unit 1 is installed in addition to the fuel supply pipe 95 and the return pipe 97. The pump unit 1 transfers the fuel in the second fuel chamber 94 to the first fuel chamber 91. Specifically, the pump unit 1 of the present embodiment includes a sub tank 3, a jet pump 74, and the like.

  The sub tank 3 corresponds to the first container recited in the claims, and stores a part of the fuel in the first fuel chamber 91. The fuel supply pipe 95, the main suction filter 96, and the return pipe 97 are installed so as to be accommodated in the sub tank 3. The sub tank 3 houses an electric pump 5 for driving the jet pump 74. A jet pump storage chamber 7 serving as a second container according to the claims for storing the jet pump 74 is formed on the side wall of the sub tank 3.

  The electric pump 5 is a pump that is driven based on a control signal from a control device 102 (hereinafter referred to as ECU), and pumps up fuel in the sub tank 3 and supplies the fuel to the jet pump 74. An electric pump suction filter 52 is provided at the suction port of the electric pump 5. The type of the pump may be a non-volumetric pump such as a regenerative pump or a volumetric pump such as a plunger pump.

  The jet pump 74 is a pump that uses a negative pressure generated when the fuel pumped up by the electric pump 5 is supplied to the main body, and uses the negative pressure to supply the fuel in the second fuel chamber 94 to the first fuel. 1 Transfer to the fuel chamber 91. A supply pipe 98 connected to the electric pump 5 and a transfer pipe 99 connected to the second fuel chamber 94 are connected to the main body of the jet pump 74.

  The fuel pumped up by the electric pump 5 is supplied to the jet pump 74 via the supply pipe 98, and a negative pressure is generated in the jet pump 74. The fuel in the second fuel chamber 94 is sucked by the negative pressure and transferred to the first fuel chamber 91 via the transfer pipe 99.

  A branch pipe 45 is provided in the middle of the supply pipe 98, and a pressure regulating valve 8 is provided at the tip of the branch pipe 45. The pressure adjusting valve 8 is a valve that adjusts the pressure in the supply pipe 98 to a predetermined pressure. When the inside of the supply pipe 98 becomes a predetermined pressure or more, the pressure regulating valve 8 is opened, excess pressure fuel (excess pressure fuel) is discharged, and the pressure in the supply pipe 98 becomes a predetermined pressure. Excess pressure fuel discharged from the pressure regulating valve 8 returns to the sub tank 3.

  The transfer capability of the jet pump 74 can be adjusted by setting the pressure in the supply pipe 98 to a predetermined pressure by the pressure adjusting valve 8. As a method of adjusting the transfer capability, a method of controlling the pump rotation speed of the electric pump 5 is conceivable, but a new control device for controlling the electric pump 5 must be provided. In the present embodiment, the transfer capacity is adjusted by using the pressure regulating valve 8 that has a simpler configuration than the control device. For this reason, an increase in manufacturing cost of the pump unit 1 can be suppressed.

  On the side wall of the sub tank 3, a sender gauge 6 is provided as a remaining amount measuring device for measuring the remaining amount of fuel in the first fuel chamber 91. The sender gauge 6 transmits a signal corresponding to the remaining fuel amount in the first fuel chamber 91 to the ECU 102. The ECU 102 calculates the remaining fuel amount based on the signal from the sender gauge 6 and transmits a signal for displaying the remaining fuel amount on the display device 103.

  In addition, when the ECU 102 determines that the calculated remaining fuel amount is lower than the predetermined remaining fuel amount, the ECU 102 transmits a signal for operating a warning that prompts the driver to refuel the warning device 104. Note that the transmission timing of this signal varies depending on the shape of the fuel tank 9 and the specification of the vehicle on which the fuel tank 9 is mounted.

  Next, details of the pump unit 1 will be described with reference to FIGS. 2 and 3. FIG. 2 is a cross-sectional view of the pump unit 1 of the present embodiment, and FIG. 3 is a view taken in the direction of the arrow III in FIG.

  As shown in FIG. 2, the pump unit 1 is disposed by being inserted into the first fuel chamber 91 from the opening 92 of the first fuel chamber 91, and is installed on the bottom surface 93 of the first fuel chamber 91. . A flange 2 that is a component of the pump unit 1 is attached to the opening 92, and the opening 92 is closed by the flange 2.

  The flange 2 is made of resin and has a substantially disk shape. A fuel supply joint pipe 21, a return joint pipe 22, a transfer joint pipe 23, and an electrical connector 24 are integrally molded on the flange 2 with resin. The fuel supply joint pipe 21 is a pipe that connects the fuel supply pipe 95 on the engine 100 side and the fuel supply hose 11 that is the fuel supply pipe 95 on the first fuel chamber 91 side. The return joint pipe 22 is a pipe that connects the return pipe 97 on the engine 100 side and the return hose 12 that is the return pipe 97 on the first fuel chamber 91 side. The transfer joint pipe 23 is a pipe that connects the transfer pipe 99 on the second fuel chamber 94 side and the transfer hose 13 that is the transfer pipe 99 on the first fuel chamber 91 side. As shown in FIG. 3, the electrical connector 24 is electrically connected to the electric pump 5 and the sender gauge 6 via lead wires (not shown), and transmits a control signal from the ECU 102 to the electric pump 5, or the electric pump 5. Power is supplied to the ECU 102, or a signal corresponding to the remaining amount of fuel in the first fuel chamber 91 from the sender gauge 6 is transmitted to the ECU 102.

  As shown in FIG. 2, an upper end portion of a shaft 25 for connecting to the sub tank 3 is fixed to the end surface of the flange 2 on the sub tank 3 side by press fitting or the like. The lower end portion of the shaft 25 is inserted into an insertion portion 33 formed in the sub tank 3 as shown in FIG. The insertion portion 33 is loosely inserted at the lower end portion of the shaft 25 so that the flange 2 and the sub tank 3 can move relatively in the vertical direction. In FIG. 2, only one shaft 25 is shown, but there are two shafts 25 as shown in FIG. Therefore, the insertion part 33 is also formed at two places as shown in FIG.

  As shown in FIG. 2, a spring 26 is provided in a compressed state between the flange 2 and the sub tank 3. The spring 26 urges the flange 2 and the sub tank 3 in a direction to separate them from each other. As a result, the resin-made first fuel chamber 91 expands or contracts due to a change in internal pressure or a change in fuel amount due to a temperature change, so that the distance between the opening 92 and the bottom surface 93 of the first fuel chamber 91 varies. Also, the sub tank 3 can be made to follow the position variation of the bottom surface 93.

  The sub tank 3 is made of resin and is a container having an upper opening. Inside the sub tank 3, a fuel supply hose 11, a return hose 12, and an electric pump 5 having a main suction filter 96 provided at the end are accommodated. Although not shown, a communication hole is formed in the bottom 32 of the sub tank 3, and a check valve that allows only the flow from the sub tank 3 to the sub tank 3 is provided in the communication hole. Thereby, when the liquid level in the sub tank 3 becomes lower than the liquid level in the first fuel chamber 91, the fuel in the first fuel chamber 91 flows into the sub tank 3. That is, the liquid level in the sub tank 3 is always higher than the liquid level in the first fuel chamber 91.

  The electric pump 5 is housed in the sub tank 3 with the state shown in FIG. 2, that is, with the discharge port 51 on the upper side in the vertical direction and the fuel suction side on the lower side in the vertical direction. The electric pump 5 has a motor (not shown) inside, and generates a fuel suction force by rotation of an impeller that rotates together with the motor. An electric pump suction filter 52 is provided on the fuel suction side of the electric pump 5 to remove foreign substances contained in the fuel.

  A cover 4 that supports the electric pump 5 is provided in the opening 31 of the sub tank 3. The electric pump 5 is supported by inserting a discharge port 51 of the electric pump 5 into a support portion 44 provided on the cover 4.

  The cover 4 includes a lower cover 43 having a support portion 44 and an upper cover 41. A support portion 44 extending toward the discharge port 51 is formed on the lower cover 43, and a branch pipe 45 extending toward the bottom portion 32 of the sub tank 3 is integrally formed. Further, a groove 46 is formed on the upper end surface of the lower cover 43. The groove portion 46 serves as a passage that communicates the support portion 44 and the branch pipe 45, and through holes 47 and 48 are formed at positions corresponding to the support portion 44 and the branch pipe 45 at the bottom of the groove portion 46. ing. Since the branch pipe 45 is formed integrally with the lower cover 43, an increase in the number of parts can be suppressed.

  The upper cover 41 is a cover that covers the groove 46 of the lower cover 43, and a joint pipe 42 is formed as a second connection pipe to which the supply hose 14 leading to the jet pump 74 is connected.

  A pressure regulating valve 8 is provided at the bottom side end of the branch pipe 45. The pressure regulating valve 8 includes a main body 81 and a valve body 84 accommodated in the main body 81. The main body 81 has a suction port 82 connected to the branch pipe 45 and a discharge port 83 on the opposite side of the suction port 82. As shown in FIGS. 2 and 3, the discharge port 83 is disposed so as to face the surface of the suction filter 52 for the electric pump installed at the bottom 32. The valve body 84 is accommodated between the suction port 82 and the discharge port 83 and is urged by a spring 85 in a direction to close the suction port 82. In the present embodiment, the main body 81 is integrally formed at the bottom side end of the branch pipe 45. The arrangement of the discharge ports 83 will be described in detail later.

  When the fuel pressure in the branch pipe 45 becomes equal to or higher than a predetermined pressure, the valve body 84 moves in the direction in which the suction port 82 and the discharge port 83 communicate with each other, and a part of the fuel in the branch pipe 45 is overpressured. It is discharged as fuel. Thereby, the pressure in the branch pipe 45 is maintained at a predetermined pressure. Since the branch pipe 45 and the supply hose 14 communicate with each other via the groove 46, the pressure in the supply hose 14 is the same as that of the branch pipe 45.

  A jet pump accommodating chamber 7 for accommodating a jet pump 74 to which the supply hose 14 is connected is formed on the side wall of the sub tank 3. The storage chamber 7 is a container having an upper opening similar to the sub tank 3. The height of the opening 71 of the storage chamber 7 from the bottom 32 of the sub tank 3 is higher than the opening 31 of the sub tank 3. A notch 72 is formed in the opening 71 opposite to the sub tank 3. The height of the lower end 73 of the notch 72 from the bottom 32 of the sub tank 3 is higher than the opening 31 of the sub tank 3.

  The supply hose 14 is connected to the upper end of the jet pump 74 and is accommodated in the accommodation chamber 7 so as to eject the fuel from the electric pump 5 toward the bottom of the accommodation chamber 7. The jet pump 74 is supported by being fitted into a recessed groove provided at the edge of the opening 71. A transfer hose 13 is connected to an intermediate portion of the jet pump 74.

  When the fuel from the electric pump 5 is supplied to the jet pump 74, a negative pressure is generated in the vicinity where the transfer hose 13 is connected. The fuel in the transfer hose 13 is sucked by this negative pressure, and the fuel in the second fuel chamber 94 is transferred to the storage chamber 7.

  As shown in FIG. 3, a sender gauge 6 is provided on the side wall of the sub tank 3. The sender gauge 6 includes a sensor part 61 and an arm part 62. The sensor unit 61 is attached to the side wall of the sub tank 3. The arm portion 62 has one end connected to the sensor portion 61 and the other end having a float (not shown). The float can float on the fuel in the first fuel chamber 91. The float moves up and down according to the fuel level in the first fuel chamber 91. The arm part 62 is rotatable around the one end part. One end of the arm portion 62 rotates according to the vertical movement of the float. The sensor unit 61 detects the rotation angle of the arm unit 62 and transmits a signal corresponding to the angle to the ECU 102 illustrated in FIG. 1 via the electrical connector 24 illustrated in FIG. A signal corresponding to the rotation angle is a signal corresponding to the remaining amount of fuel in the first fuel chamber 91.

  When the ECU 102 determines that the signal corresponding to the remaining fuel amount from the sender gauge 6 is a signal indicating that the signal has fallen to the position of the one-dot chain line shown in FIG. As described above, the warning device 104 shown in FIG. 1 is transmitted with a signal for operating a warning that prompts the driver to refuel.

  Next, the operation of the pump unit 1 will be described. When a control signal and electric power are supplied from the ECU 102 to the electric pump 5, the electric pump 5 pumps up the fuel in the sub tank 3 and discharges the fuel pumped up from the discharge port 51. The discharged fuel passes through the support portion 44 and is supplied to the joint pipe 42 and the branch pipe 45. The fuel supplied to the joint pipe 42 is supplied to the jet pump 74 via the supply hose 14.

  By driving the jet pump 74, the fuel in the second fuel chamber 94 is transferred to the storage chamber 7 via the transfer pipe 99, the transfer joint pipe 23 and the transfer hose 13 on the second fuel chamber 94 side. When the storage chamber 7 is filled with fuel, the fuel overflows from the opening 71 into the first fuel chamber 91.

  Here, when the fuel in the second fuel chamber 94 decreases and air enters the transfer pipe 99, the air in the second fuel chamber 94 is ejected from the jet pump 74. Then, the fuel in the storage chamber 7 bubbles and bubbles are mixed into the fuel. In this embodiment, light oil is used as the fuel. In particular, since light oil is higher in viscosity than fuel for gasoline engines, it takes a relatively long time for the mixed bubbles to disappear.

  Since the opening 71 of the storage chamber 7 is located higher than the opening 31 of the sub tank 3, there is a possibility that fuel containing bubbles overflowing from the storage chamber 7 flows into the sub tank 3. If the electric pump 5 or the pump 101 shown in FIG. 1 sucks the fuel containing bubbles, the electric pump 5 cannot pump up the fuel or cannot supply an appropriate amount of fuel to the engine 100. To do. Moreover, in the pump 101, there exists a possibility that the malfunction that a pump part may seize may generate | occur | produce.

  In the present embodiment, since the notch 72 is formed in the opening 71 on the opposite side of the storage chamber 7 from the sub tank 3, the fuel containing bubbles is forcibly discharged from the notch 72. That is, the inflow to the sub tank 3 can be suppressed.

  When the electric pump 5 stops, the jet pump 74 also stops, so that the transfer from the second fuel chamber 94 stops. As shown in FIG. 1, when the electric pump 5 stops in a state where the liquid level of the fuel in the second fuel chamber 94 is lower than the liquid level in the first fuel chamber 91, the fuel in the storage chamber 7 is transferred to the jet pump 74. In other words, a so-called siphon phenomenon occurs that flows back to the second fuel chamber 94 via the transfer hose 13, the transfer joint pipe 23 and the transfer pipe 99. This phenomenon is likely to occur when the vehicle is parked on a slope. This reverse flow continues until air flows into the jet pump 74, the transfer hose 13, the transfer joint pipe 23, and the transfer pipe 99 to reach an atmospheric pressure state.

  In this embodiment, since the air hole for stopping the siphon phenomenon is not formed in the transfer hose 13 or the supply hose 14, the backflow causes the fuel level in the first fuel chamber 91 to be the opening of the storage chamber 7. This continues until the height of 71 becomes lower and the fuel level in the storage chamber 7 becomes lower than the discharge port of the jet pump 74 and air flows in from the discharge port.

  In the present embodiment, the opening 71 of the storage chamber 7 is higher than the opening 31 of the sub-tank 3, so that the first time is earlier than when the opening 71 is lower than the opening 31. The fuel level in the fuel chamber 91 is lower than the height of the opening 71 of the storage chamber 7. For this reason, the backflow of the fuel to the 2nd fuel chamber 94 can be stopped quickly, and the quantity of the fuel which flows back can be suppressed.

  In the present embodiment, since no air hole is formed in the transfer hose 13 or the supply hose 14, when the electric pump 5 is driven, the fuel pumped up by the electric pump 5 does not leak from the air hole. For this reason, the work volume of the pump unit 1 with respect to the electric power supplied to the electric pump 5 can be suppressed.

  Next, the pressure regulating valve 8 provided in the branch pipe 45 will be described. In this embodiment, the pressure regulating valve 8 and the branch pipe 45 are formed so that the height of the discharge port 83 is at a position lower than the warning level. By setting the height of the discharge port 83 to a position lower than the warning level, the discharge port 83 can be submerged in the fuel. As a result, the overpressure fuel discharged from the discharge port 83 is not struck against the fuel in the sub tank 3, and the fuel in the sub tank 3 can be prevented from foaming. As a result, the electric pump 5 and the pump 101 can be suppressed from sucking the fuel mixed with bubbles, and the occurrence of the above-described problems can be suppressed.

  The discharge port 83 may be anywhere as long as its height is lower than the warning level and the branch pipe 45 does not interfere with other parts. For example, you may arrange | position the branch piping 45 and the discharge port 83 in the position shown with the broken line in FIG. The branch pipe 45 is preferably arranged so that the discharge port 83 faces the surface of the suction filter 52 for the electric pump. By disposing the discharge port 83 at this position, the electric pump 5 can pump up the fuel by using the jet of fuel discharged from the discharge port 83. Thereby, the efficiency of the electric pump 5 can be improved, and by extension, the efficiency of the pump unit 1 can also be improved.

  In the present embodiment, the branch pipe 45 is formed in the cover 4 so as to extend toward the bottom 32 of the sub tank 3, and the pressure regulating valve 8 is provided at the bottom side end of the branch pipe 45. A discharge port 83 is formed in the main body 81 of the pressure regulating valve 8. For this reason, it is not necessary to form any passage between the main body 81 and the discharge port 83, and the structure of the pump unit 1 is simplified.

  Further, the pump unit 1 of the present embodiment may be applied to a so-called vertical type fuel tank in which the first fuel chamber and the second fuel chamber are connected at the top. The fuel stored in the fuel tank may be a gasoline engine fuel.

(Second Embodiment)
A pump unit according to a second embodiment of the present invention will be described below with reference to FIG.

  The pressure regulating valve 8 provided in the pump unit 1 according to the first embodiment is provided at the bottom side end of the branch pipe 45 formed integrally with the cover 4, but the pump unit according to the second embodiment. The pressure regulating valve 8a provided in 1a differs from the first embodiment in that it is provided in the supply hose 14.

  Specifically, as shown in FIG. 4, the pressure regulating valve 8 a is provided at a joint portion of the supply hose 14 on the jet pump 74 side. The pressure regulating valve 8a includes a main body portion 81a having a suction port 82a connected to the supply hose 14, a valve body 84a that is accommodated in the main body portion 81a and opens and closes the suction port 82a, and biases the valve body 84a to the suction port 82a. And a deformable hose portion 86 connected to the main body portion 81a. The tip of the hose portion 86 is a discharge port 83a. The discharge port 83a is at a position lower than the warning level indicated by the one-dot chain line in FIG.

  When the fuel pressure in the supply hose 14 becomes equal to or higher than a predetermined pressure, the valve body 84a moves in the direction in which the suction port 82a opens due to the pressure, and a part of the fuel in the supply hose 14 is discharged through the hose portion 86. It is discharged from 83a.

  In this embodiment, even if the pressure regulating valve 8a is at a relatively high position, the overpressure fuel is conveyed to the bottom 32 of the sub tank 3 by the hose portion 86 provided in the main body portion 81a. For this reason, it is possible to prevent air bubbles from being mixed into the fuel in the sub tank 3 when the fuel is discharged from the discharge port 83a. Moreover, since the hose part 86 can be deformed, the degree of freedom of arrangement of the discharge port 83a increases.

It is a schematic block diagram of the fuel supply system to which the pump unit of this invention is applied. It is sectional drawing of the pump unit which concerns on 1st Embodiment of this invention. FIG. 3 is an arrow view in the III direction in FIG. 2. It is sectional drawing of the pump unit which concerns on 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pump unit, 11 Fuel supply hose, 12 Return hose, 13 Transfer hose (1st connection piping), 14 Supply hose, 2 Flange, 23 Transfer joint pipe (1st connection piping), 3 Sub tank (1st container), 31 Opening (upper end), 32 bottom, 4 cover, 41 upper cover, 42 joint piping (second connection piping), 43 lower cover, 44 support, 45 branch piping, 46 groove, 5 electric pump, 51 discharge port, 52 Suction filter for electric pump, 6 Sender gauge (remaining amount measuring device), 7 Jet pump storage chamber (second container), 71 Opening (upper end), 72 Notch, 73 Lower end, 74 Jet pump, 8 Pressure tuning valve,
81 Body, 82 Suction port, 83 Discharge port, 84 Valve body, 85 Spring, 9 Fuel tank, 91 1st fuel chamber, 94 2nd fuel chamber, 95 Fuel supply piping, 96 Main suction filter, 97 Return piping, 98 Supply piping, 99 Transfer piping (first connection piping), 100 Engine, 102 Control device (ECU), 104 Warning device

Claims (9)

A pump unit that is housed in the first fuel chamber of a fuel tank having a first fuel chamber and a second fuel chamber, and transfers the fuel in the second fuel chamber to the first fuel chamber;
A first container for accumulating fuel;
An electric pump housed in the first container and pumping up the fuel in the first container;
A second container that is provided on a side wall of the first container and accumulates fuel;
A jet pump housed in the second container and driven by fuel pumped from the electric pump, connected to the second fuel chamber by a first connecting pipe, and fuel in the second fuel chamber A jet pump for transfer to one fuel chamber;
A pressure adjusting valve that adjusts the fuel pressure supplied to the jet pump by discharging part of the fuel supplied to the jet pump from the electric pump,
The pump unit according to claim 1, wherein the pressure regulating valve has a discharge port for discharging the discharged fuel, and the discharge port is disposed at a bottom portion of the first container. A remaining amount measuring device for generating a signal corresponding to the remaining amount of fuel in the first fuel chamber;
The signal generated by the remaining amount measuring device is transmitted to a warning device that generates a warning that prompts the driver to refuel when the remaining amount of fuel in the first fuel chamber is less than a predetermined remaining amount,
2. The pump unit according to claim 1, wherein the discharge port is disposed below a liquid level of the first fuel chamber when the warning device generates the warning. The electric pump has a suction filter on the bottom side of the first container,
The pump unit according to claim 1 or 2, wherein the discharge port is disposed so as to face the surface of the suction filter. The first container is covered with a cover that supports the electric pump,
The cover is integrally formed with a second connection pipe that is a part of the passage between the electric pump and the jet pump, and a branch pipe that branches from the second connection pipe and extends toward the bottom of the first container. Formed into
The pump unit according to any one of claims 1 to 3, wherein the pressure regulating valve is provided in the branch pipe. The pressure regulating valve is provided at a bottom side end of the branch pipe;
5. The pump unit according to claim 4, further comprising: a main body portion having a suction port connected to the branch pipe and the discharge port; and a valve body housed in the main body portion for opening and closing the suction port. . The pressure regulating valve is provided in the middle of the passage between the electric pump and the jet pump,
The pressure regulating valve includes a main body having an inlet connected to the passage, a valve body accommodated in the main body for opening and closing the inlet, and connected to the main body, and the discharge port is formed at a tip. The pump unit according to any one of claims 1 to 3, further comprising a deformable hose portion.   The pump unit according to any one of claims 1 to 6, wherein a height of an upper end portion of the second container from a bottom portion of the first container is higher than an upper end portion of the first container. .   The pump unit according to claim 7, wherein a notch is formed in the upper end portion of the second container opposite to the first container.   The pump unit according to claim 8, wherein a height of a lower end portion of the notch portion from a bottom portion of the first container is higher than the upper end portion of the first container.

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