JP4715793B2 - Pumping unit - Google Patents

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 subtank divided into a main chamber and a subchamber by a partition wall, an electric pump housed in the main chamber and pumping up fuel in the main chamber, and a fuel pumped up by the electric pump and housed in the subchamber. 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.

An air hole is formed in the middle of the passage connecting the electric pump and the jet pump, and when the electric pump is stopped, air is allowed to flow from the first fuel chamber into the second passage through the air hole. The phenomenon of fuel flowing back into the fuel chamber (siphon phenomenon) is stopped.
JP 2004-316567 A

  However, if an air hole is formed in the passage, the siphon phenomenon when the electric pump is stopped can be stopped relatively early, but when the electric pump is driven, a part of the fuel pumped up by the electric pump is jetted. It is discharged from the air hole without being supplied to the pump. For this reason, there is a problem that the overall pump efficiency of the pump unit including when the electric pump is driven and when it is stopped is lowered. Pump efficiency here refers to the ratio of the work done by the pump unit to the electric power supplied to the electric pump.

  The present invention has been made to solve the above problems, and is efficient 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. An object is to provide a pump unit.

  When the electric pump that drives the jet pump stops, the liquid level in the first fuel chamber is higher than the liquid level in the second fuel chamber, and the jet pump is submerged in the fuel in the first fuel chamber If so, the fuel in the first fuel chamber flows back to the second fuel chamber through the jet pump and the connecting pipe. This reverse flow continues until air flows into the jet pump and the connecting pipe and reaches an atmospheric pressure state.

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 by an electric pump, the jet pump being connected to a second fuel chamber by a connecting pipe and transferring fuel in the second fuel chamber to the first fuel chamber; The upper end of the second container is higher than the upper end of the first container.

  According to this configuration, the jet pump is accommodated in the second container. When the electric pump stops and the above-described reverse flow phenomenon occurs, the fuel in the second container is sucked from the jet pump and flows back into the second fuel chamber. However, when the liquid level in the first fuel chamber is higher than the upper end of the second container, the fuel in the first fuel chamber flows into the second container. Therefore, the reverse flow to the second fuel chamber causes the liquid level in the first fuel chamber to be lower than the upper end of the second container, and the liquid level in the second container to be lower than the discharge port of the jet pump. It will continue until air is inhaled.

In this invention, the upper end portion of the second container is higher than the upper end portion of the first container. According to this configuration, the time until the liquid level in the first fuel chamber becomes lower than the upper end of the second container after the electric pump is stopped and the reverse flow phenomenon to the second fuel chamber occurs is shortened. can do. That is, backflow can be stopped as soon as possible without providing an air hole as in the prior art.

  Since there is no need to provide an air hole in the passage between the electric pump and the jet pump or the passage between the jet pump and the second fuel chamber, the fuel pumped up by the electric pump is discharged from the air hole in the middle. It is possible to suppress a reduction in the efficiency of the electric pump. As a result, it is possible to suppress a decrease in the overall pump efficiency of the pump unit including when the electric pump is driven and when it is stopped.

  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 above 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 air bubbles flow into the first container, there is a problem that the electric pump sucks the air bubbles and cannot pump up the fuel. In addition, if a pump that supplies fuel to the engine sucks bubbles, 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.

  On the other hand, according to the invention described in claim 2, the second container is characterized in that a notch is formed in the upper end 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 the air bubbles.

According to invention of Claim 3, 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 configuration, since the lower end portion of the notch is higher than the upper end portion of the first container, the phenomenon of backflowing the connecting pipe when the electric pump is stopped can be stopped at an early stage. A decrease in the overall pump efficiency of the pump unit including when the pump is driven and when it is stopped can be suppressed.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 3. 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. The main body of the jet pump 74 is connected to a supply pipe 98 connected to the electric pump 5 and a transfer pipe 99 as a connection pipe described in the claims connected to the second fuel chamber 94.

  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.

  A sender gauge 6 for measuring the remaining amount of fuel in the first fuel chamber 91 is provided on the side wall of the sub tank 3. 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 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. The upper cover 41 is a cover that covers the groove 46, and a joint pipe 42 to which the supply hose 14 that communicates with the jet pump 74 is connected is formed.

  A pressure regulating valve 8 is provided at the bottom side end of the branch pipe 45. The pressure regulating valve 8 discharges a part of the fuel in the branch pipe 45 from the discharge port when the fuel pressure in the branch pipe 45 becomes a predetermined pressure or more, and the pressure in the branch pipe 45 and the supply hose 14 is discharged. Is adjusted to a predetermined pressure. The discharge port of the pressure regulating valve 8 is arranged so as to face the surface of the suction filter 52 for the electric pump, and the electric pump 5 sucks the fuel discharged from the discharge port.

  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 that opens upward like the sub tank 3. The opening 71 of the storage chamber 7 is higher in height from the bottom 32 of the sub tank 3 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 lower end 73 of the notch 72 is also higher than the opening 31 of the sub tank 3 from the bottom 32 of the sub tank 3.

  The jet pump 74 is connected to the supply hose 14 at the upper end, and has a discharge port 75 through which the supplied fuel is ejected at the lower end, and the discharge port 75 faces the bottom of the storage chamber 7 into the storage chamber 7. Contained. 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. In the present embodiment, the transfer hose 13 and the supply hose 14 are not formed with air holes as in the prior art.

  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. The one end of the arm 62 rotates in accordance with 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 dropped to the position of the one-dot chain line shown in FIG. 2 (this position is referred to as a warning level), as described above. In FIG. 1, a signal for operating a warning that prompts the driver to refuel is transmitted to the warning device 104 shown in FIG.

  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 33, 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 discharge port 75 of 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. 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 supply of fuel to the jet pump 74 stops, so the jet pump 74 also 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.

  As shown in FIG. 2, when the liquid level of the first fuel chamber 91 is in the state I, the storage chamber 7 is filled with fuel, so the fuel in the storage chamber 7 flows back to the second fuel chamber 94. . When the fuel in the storage chamber 7 flows back to the second fuel chamber 94 and the liquid level in the first fuel chamber 91 is in the II state, that is, the liquid level is the lower end 73 of the notch 72 in the storage chamber 7. When the height falls below the height H, the flow of the fuel into the first fuel chamber 91 into the storage chamber 7 stops.

  Even after the inflow of fuel into the first chamber 91 is stopped, the reverse flow phenomenon continues, but the liquid level in the chamber 7 is lower than the discharge port 75 of the jet pump 74, and the discharge port 75. When air flows into the jet pump 74, the reverse flow phenomenon stops. Since the volume of the storage chamber 7 is only a volume that can accommodate the jet pump 74, the backflow is quickly stopped after the liquid level of the first fuel chamber 91 becomes II.

  In the present embodiment, since the height H of the lower end 73 of the notch 72 is higher than the height h of the opening 31 of the sub tank 3, the electric pump 5 is stopped and the back flow into the second fuel chamber 94 is performed. It is possible to shorten the time from when this phenomenon occurs until the liquid level in the first fuel chamber 91 is in the state II, that is, lower than the lower end 73 of the notch 72. The reverse flow can be stopped as much as possible without providing an air hole for stopping the reverse flow phenomenon in the transfer hose 13 and the supply hose 14 as in the prior art.

  Further, since the backflow can be stopped early without forming an air hole in the transfer hose 13 or the supply hose 14, the efficiency of the electric pump 5 due to the fuel pumped up by the electric pump 5 being discharged from the air hole in the middle. Can be suppressed. As a result, it is possible to suppress a decrease in the overall pump efficiency of the pump unit 1 including when the electric pump 5 is driven and when it is stopped.

  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.

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 one Embodiment of this invention. FIG. 3 is an arrow view in the III direction in FIG. 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pump unit, 11 Fuel supply hose, 12 Return hose, 13 Transfer hose (connection pipe), 14 Supply hose, 2 Flange, 21 Fuel supply joint pipe, 22 Return joint pipe, 23 Transfer joint pipe (connection pipe), 3 Sub tank (First container), 31 opening (upper end), 4 cover, 42 joint piping, 44 support section, 45 branch piping, 46 groove section, 5 electric pump, 51 discharge port, 6 sender gauge, 7 jet pump storage chamber (first 2 container), 71 opening (upper end), 72 notch, 73 lower end, 74 jet pump, 75 outlet, 8 pressure regulating valve, 9 fuel tank, 91 first fuel chamber, 94 second fuel chamber, 95 fuel supply pipe, 96 main suction filter, 97 return pipe, 98 supply pipe, 99 transfer pipe (connection pipe), 100 Engine, 101 pump, 102 Control unit (ECU)

Claims (3)

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 up by the electric pump, connected to the second fuel chamber by a connecting pipe, and fuel in the second fuel chamber is transferred to the first fuel chamber A pump unit comprising a transporting jet pump,
The upper end portion of the second container, a pump unit being higher than the upper end portion of the front Symbol first container.   2. The pump unit according to claim 1, wherein a notch portion is formed in the upper end portion of the second container opposite to the first container. Pump unit according to claim 2 wherein the lower end of the cutout portion, which being higher than the upper end of the front Symbol first container.

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