Fuel supply device

Abstract

A fuel supply device (10) comprises: a sub-tank (30); a fuel pump (40); and a relief valve (50). The sub-tank (30) is installed at the bottom in a fuel tank (T). Fuel that has been guided into the sub-tank (30) from the inside of the fuel tank (T) and has passed through a fuel filter (34) is pumped to an engine by the fuel pump (40). The relief valve (50) adjusts the pressure of the fuel spewed out from the fuel pump (40). A valve case (53) for housing the relief valve (50) is provided above the sub-tank (30). In the valve case (53), a fuel discharge hole (534h) for discharging excess fuel flowed out from the relief valve (50) is formed. The fuel discharge hole (534h) penetrates the outer circumferential wall of the valve case (53). The fuel discharge hole (534h) faces downward and is positioned so as to face a fuel reception opening (32e) of the sub tank (30).

Description

fuel supply device

[0001] The present disclosure relates to a fuel supply system.

[0002] A fuel supply device is disclosed, for example, in Japanese Patent No. 6907145. As shown in FIG. 8, the fuel supply device 110 of Japanese Patent No. 6907145 includes a sub-tank 112 and a fuel pump (not shown). The sub-tank 112 is installed at the bottom of the fuel tank 100. The fuel pump guides fuel from the fuel tank 100 into the sub-tank 112, passes the fuel through a fuel filter 114, and pumps the fuel to the engine (not shown). The pressure of the fuel discharged from the fuel pump is adjusted by a relief valve (not shown). A valve case 116 that houses the relief valve is provided on the sub-tank 112.

[0003] As shown in Figure 9, the valve case 116 is disposed horizontally. The valve case 116 has a case main body 117 and a cap 118. The cap 118 is coaxially connected to the case main body 117. The cap 118 is formed in a cylindrical shape with a top. A fuel discharge pipe 118p is formed in the ceiling of the cap 118 to discharge excess fuel that has flowed out from the relief valve. The fuel discharge pipe 118p extends downward and guides fuel to a fuel receiving cylindrical portion 112u at the upper corner of the sub-tank 112.

[0004] In the valve case 116, a fuel discharge pipe 118p extends downward from the ceiling of the cap portion 118. Therefore, when molding the cap portion 118, the presence of the fuel discharge pipe 118p complicates the mold structure, increasing the manufacturing cost of the cap portion 118. Therefore, there has been a conventional need to simplify the mold structure used to mold a valve case with a fuel discharge hole.

[0005] According to one aspect of the present disclosure, a fuel supply device includes a sub-tank, a fuel pump, and a relief valve. The sub-tank is installed at the bottom of the fuel tank. The fuel pump guides fuel from the fuel tank through a fuel filter into the sub-tank and then pumps the fuel to an engine. The relief valve adjusts the pressure of fuel discharged from the fuel pump. A valve case that houses the relief valve is provided on the sub-tank. The valve case is formed with a fuel discharge hole that discharges excess fuel that flows out from the relief valve. The fuel discharge hole is formed through an outer peripheral wall of the valve case. The fuel discharge hole faces downward and is positioned to face a fuel receiving opening of the sub-tank.

[0006] A fuel discharge hole is formed through the outer peripheral wall of the valve case. Therefore, compared to conventional cases in which a fuel discharge pipe is formed in the valve case, the mold structure for molding the valve case can be simplified by the absence of a pipe-shaped protrusion. Furthermore, the fuel discharge hole in the valve case faces downward and is positioned so as to face the fuel receiving opening of the sub-tank. Therefore, even though the fuel discharge hole in the valve case does not have a pipe-shaped protrusion, excess fuel that flows out from the fuel discharge hole can be returned to the sub-tank.

[0007] According to another feature of the present disclosure, a guide wall portion is formed around the fuel receiving opening of the sub-tank so as to protrude upward. The guide wall portion guides excess fuel that has flowed out from the fuel discharge hole of the valve case to the fuel receiving opening. This makes it easier for the excess fuel that has flowed out from the fuel discharge hole of the valve case to return to the sub-tank.

[0008] According to another feature of the present disclosure, the valve case includes a case main body and a cap coaxially connected to the case main body. The valve case is arranged so that its axis is oriented horizontally. The cap has a cylindrical portion and a lid that closes the tip end of the cylindrical portion. The fuel discharge hole is formed across the boundary between the cylindrical portion and the lid. Therefore, fuel flowing out from the fuel discharge hole is guided by the lid of the cap, making it less likely to spread axially outward from the cap.

[0009] According to another feature of the present disclosure, the fuel receiving opening of the sub-tank is formed on the upper surface of a corner of the sub-tank, and the guide wall portion is formed in an L-shape in plan view at a position where the adjacent vertical wall portions constituting the corner of the sub-tank extend upward, which makes it easy to mold the guide wall portion.

[0010] FIG. 1 is a rear view of the fuel supply device according to the first embodiment of the present disclosure. FIG. 2 is a perspective view of the fuel supply device as viewed from above and front. FIG. 3 is a longitudinal cross-sectional view (cross-sectional view taken along the III-III arrows in FIG. 2) of a pump unit of the fuel supply device. FIG. 4 is a perspective view of a sub-tank of the fuel supply device as viewed from above and front. FIG. 5 is a left side view of the valve case and sub-tank that constitute the pump unit. FIG. 6 is a perspective view of a cap portion of the valve case and a left rear corner of the sub-tank as viewed from diagonally below and rear. FIG. 7 is a rear view of a conventional fuel supply device. FIG. 8 is a perspective view of a valve case and a left rear corner of the sub-tank in a conventional fuel supply device as viewed from diagonally above and rear.

[0011] 1 to 7, a fuel supply device 10 according to a first embodiment of the present disclosure will be described. The fuel supply device 10 is a device that supplies (pressure-feeds) fuel in a fuel tank T to a vehicle engine. Here, the front, rear, left, right, and top and bottom shown in the drawings correspond to the front, rear, left, right, and top and bottom of the fuel supply device 10.

[0012] <Overview of Fuel Supply Device 10> As shown in Figures 1 and 2, the fuel supply device 10 includes a flange unit 12, a pump unit 20, and a joint member 14. The flange unit 12 closes the upper opening Th of the fuel tank T. The pump unit 20 pumps fuel. The joint member 14 connects the flange unit 12 and the pump unit 20 in a state where they can move relative to each other in the vertical direction. The joint member 14 applies a downward spring force to the pump unit 20. Therefore, with the flange unit 12 fixedly closing the upper opening Th of the fuel tank T, the spring force of the joint member 14 presses the pump unit 20 against the bottom surface of the fuel tank T.

[0013] <Overview of Pump Unit 20> As shown in Figures 2 to 4, the pump unit 20 includes a sub-tank 30, a fuel pump 40, and a relief valve 50. The sub-tank 30 stores fuel at the bottom of the fuel tank T. The fuel pump 40 pumps the fuel in the sub-tank 30 to the engine. The relief valve 50 adjusts the pressure of the fuel discharged from the fuel pump 40. The pump unit 20 includes a pump case 43 and a valve case 53 that house the fuel pump 40 and the relief valve 50, respectively, above the sub-tank 30.

[0014] <Subtank 30> As shown in Figure 3 and other figures, the subtank 30 includes a subtank body 32, a fuel filter 34, and a cover member 36. The subtank body 32 is a shallow, rectangular box with an opening (figure number omitted) on the bottom side. The fuel filter 34 closes the opening on the bottom side of the subtank body 32. The cover member 36 presses the fuel filter 34 from below. The cover member 36 is formed in the shape of a roughly rectangular lattice plate. The peripheral edge of the cover member 36 is connected to the peripheral edge of the subtank body 32. The peripheral edge of the cover member 36, together with the peripheral edge of the subtank body 32, holds the peripheral edge of the fuel filter 34 in place.

[0015] As shown in FIG. 4 , an upper opening 32h is formed on the top surface of the subtank body 32, positioned toward the right of the center in the width direction (front-rear direction). A connecting pipe 34c (described below) of the fuel filter 34 is inserted through the upper opening 32h. A fuel receiving opening 32e is formed on the top surface of the subtank body 32. The fuel receiving opening 32e is vertically oriented and cylindrical. The fuel receiving opening 32e is located at the left rear corner of the subtank body 32 and communicates with the internal space of the subtank 30. A guide wall portion 32k having an L-shape in plan view is formed on the subtank body 32. The guide wall portion 32k surrounds the fuel receiving opening 32e from the left and rear sides. The guide wall portion 32k extends upward from the left rear corner of the subtank body 32 and constitutes the left vertical wall portion and the rear vertical wall portion of the subtank body 32.

[0016] <Fuel Filter 34> As shown in FIG. 3, the fuel filter 34 is a flat, generally rectangular bag-shaped filter made of nonwoven fabric. A connecting pipe 34c is attached to the top surface of the fuel filter 34. The connecting pipe 34c is located corresponding to the top opening 32h of the sub-tank body 32. The connecting pipe 34c communicates with the internal space of the fuel filter 34. As shown in FIG. 3, the connecting pipe 34c of the fuel filter 34 is connected to a fuel intake port 44 of the fuel pump 40 via a fuel intake line 41. Therefore, when the fuel pump 40 is driven, fuel in the fuel tank T is introduced into the sub-tank 30, filtered by the fuel filter 34, and then sucked into the fuel intake port 44 of the fuel pump 40.

[0017] <Pump Case 43, etc.> As shown in Figures 2 and 3, the pump case 43 is a cylindrical case that houses the fuel pump 40 horizontally on the subtank body 32. As shown in Figure 2, the outer periphery of the right end of the pump case 43 is connected to the outer periphery of the fuel suction line 41. As shown in Figure 2, the outer periphery of the left end of the pump case 43 is connected to the outer periphery of the pump-side end of the fuel discharge line 47. As shown in Figure 3, the fuel discharge port 45 of the fuel pump 40 communicates with the fuel discharge line 47. The fuel discharge line 47 is a substantially L-shaped line that guides fuel discharged from the fuel pump 40 to a valve case 53 of the relief valve 50. The tip of the fuel discharge line 47 is connected to the underside of the valve case 53.

[0018] <Relief Valve 50> The relief valve 50 includes a pressure-receiving member (not shown) that receives fuel pressure, a spring material (not shown) that supports the pressure-receiving member, and a valve body (not shown) that opens and closes the fuel flow path by displacement of the pressure-receiving member. When the pressure of fuel discharged from the fuel pump 40 exceeds a set pressure, the pressure-receiving member of the relief valve 50 receives the pressure and displaces against the force of the spring material, opening the fuel flow path in the valve body. This allows excess fuel to escape outside the relief valve 50, adjusting the fuel pressure to return to the set pressure. Note that when the fuel pressure becomes lower than the set pressure, the force of the spring material returns the pressure-receiving member to its original position, closing the fuel flow path in the valve body.

[0019] <Valve Case 53> As shown in Figures 2 and 5, the valve case 53 is a case that houses and supports the relief valve 50 in a horizontal position. The valve case 53 includes a case main body 510 having a cylindrical internal space and a cap portion 530. The cap portion 530 closes the opening at the rear end side (one axial end side) of the case main body 510 and is coaxially connected to the case main body 510. As shown in Figures 3 and 5, the case main body 510 is provided with a fuel inlet port 512 on its underside. The fuel discharge line 47 on the fuel pump 40 side is connected to the fuel inlet port 512.

[0020] As shown in FIG. 5 , the case body 510 is provided with an inverted-L-shaped discharge conduit 514. The inverted-L-shaped discharge conduit 514 protrudes axially forward from the case body 510 and is bent downward. A fuel outlet port 514p is formed at the tip of the inverted-L-shaped discharge conduit 514. The base end of the discharge fuel pipe 13 is connected to the fuel outlet port 514p. The tip of the discharge fuel pipe 13 is connected to the fuel discharge port 12p (see FIG. 2) of the flange unit 12. As shown in FIGS. 5 to 7 , a claw receiver 516 is formed on the outer peripheral surface of the case body 510 of the valve case 53, with which the engaging claw 536 of the cap portion 530 engages. The claw receivers 516 are formed symmetrically on the right and left sides of the case body 510. As shown in FIG. 6 , the claw receiver 516 is formed in a generally wedge shape and includes a wedge inclined surface 516s and a receiver body 516m (see FIG. 5). The wedge inclined surface 516s protrudes more toward the front side of the case main body 510. The receiving portion main body 516m is formed in a stepped shape at the front side of the wedge inclined surface 516s (rear end of the wedge).

[0021] <Cap portion 530 of valve case 53> The cap portion 530 seals and closes the opening on the rear end side of the case main body 510. As shown in FIGS. 5 to 7 , the cap portion 530 includes a cylindrical portion 532 and a disk-shaped lid portion 534 that closes the front end side (rear end opening) of the cylindrical portion 532. A fuel discharge hole 534h is formed on the underside of the cap portion 530 at a position that straddles the boundary between the lid portion 534 and the cylindrical portion 532. The fuel discharge hole 534h is a hole that discharges excess fuel that has flowed out of the relief valve 50 to the outside of the valve case 53, and penetrates the outer peripheral wall of the cap portion 530. Because the fuel discharge hole 534h of the cap portion 530 can be formed as a through-hole in this way, the mold structure for forming the cap portion 530 can be simplified.

[0022] As shown in FIGS. 5 to 7 , the cap portion 530 is formed with engagement claws 536. The engagement claws 536 protrude forward from left and right positions on the outer peripheral surface of the front end of the cylindrical portion 532, i.e., from left and right positions axially opposite the lid portion 534. As shown in FIG. 5 , the engagement claws 536 are plate members with a generally horizontal U-shaped side. The engagement claws 536 are curved in an arc so as to cover the outer peripheral surface of the case main body 510. The claw receiver 516 of the case main body 510 can be accommodated in an opening (illustration number omitted) in the center of the engagement claw 536. A claw main body 536t is formed at the front end of the opening of the engagement claw 536, and is adapted to be hooked onto the receiver main body 516m of the claw receiver 516 of the case main body 510.

[0023] The engaging claws 536 are flexible and configured to be elastically deformable in the radial direction. Therefore, when the cap portion 530 is placed axially (rearward) over the opening of the case body 510, the engaging claws 536 elastically deform and move over the claw receivers 516 of the case body 510. Then, when the cap portion 530 is completely placed over the case body 510, the claw bodies 536t of the engaging claws 536 engage with the receiver bodies 516m of the claw receivers 516. In this state, the cap portion 530 is fixed to the case body 510.

[0024] When the cap portion 530 is fixed to the case main body 510, the fuel discharge hole 534h of the cap portion 530 is positioned to face the fuel receiving opening 32e (see FIG. 4) on the top surface of the subtank main body 32. That is, the fuel discharge hole 534h of the cap portion 530 is positioned directly above the fuel receiving opening 32e of the subtank main body 32. Also, as shown in FIG. 5, the lid portion 534 of the cap portion 530 is positioned in front of the rear wall portion of the guide wall portion 32k of the subtank main body 32. Therefore, excess fuel discharged from the fuel discharge hole 534h of the cap portion 530 is guided by the guide wall portion 32k and returned to the subtank main body 32 through the fuel receiving opening 32e. Here, because the guide wall portion 32k is positioned lower than the cap portion 530 of the valve case 53, the guide wall portion 32k does not interfere with the attachment of the cap portion 530 to the case main body 510.

[0025] <Operation of Fuel Supply Device 10> When fuel pump 40 is driven, as shown in Figure 3, fuel in fuel tank T is introduced into sub-tank 30, filtered by fuel filter 34, and then sucked into fuel intake port 44 of fuel pump 40 via connecting pipe 34c and fuel intake line 41. The fuel sucked into fuel intake port 44 of fuel pump 40 is pressurized by fuel pump 40 and discharged from fuel outlet port 45. The fuel discharged from fuel outlet port 45 of fuel pump 40 is guided into valve case 53 of relief valve 50 via fuel discharge line 47.

[0026] The fuel introduced into the valve case 53 presses the pressure-receiving member of the relief valve 50. At this time, if the fuel pressure is greater than the set pressure, the pressure-receiving member is displaced against the force of the spring material. This opens the fuel flow path in the valve body of the relief valve 50, and excess fuel is discharged outside the relief valve 50. This adjusts the fuel pressure to return to the set pressure. The fuel whose pressure has been adjusted by the relief valve 50 is pumped from the fuel outlet port 514p of the inverted L-shaped discharge pipe 514 of the valve case 53 through the discharge fuel pipe 13 and the fuel discharge port 12p of the flange unit 12 to the engine.

[0027] The excess fuel that has been released to the outside of the relief valve 50 is discharged from a fuel discharge hole 534h formed in the cap portion 530 of the valve case 53. The excess fuel that has been discharged from the valve case 53 is guided by the guide wall portion 32k of the subtank body 32 and led to the fuel receiving opening 32e (see FIG. 4), and is returned into the subtank body 32 from the fuel receiving opening 32e.

[0028] Advantages of the Fuel Supply Device 10 According to the Present Embodiment In the fuel supply device 10 according to the present embodiment, the valve case 53 is formed with a fuel discharge hole 534h for discharging excess fuel that has leaked out from the relief valve 50. The fuel discharge hole 534h penetrates the outer peripheral wall of the valve case 53. Therefore, compared to conventional cases in which a fuel discharge pipe is formed in the valve case 53, the mold structure for molding the valve case 53 can be simplified by eliminating the pipe-shaped protrusion. Furthermore, the fuel discharge hole 534h in the valve case 53 faces downward and is positioned so as to face the fuel receiving opening 32e (see FIG. 4 ) in the subtank body 32. Therefore, even though the fuel discharge hole 534h in the valve case 53 does not have a pipe-shaped protrusion, excess fuel that has leaked out from the fuel discharge hole 534h can be returned into the subtank body 32.

[0029] A guide wall portion 32k is formed to protrude upward around the fuel receiving opening 32e of the subtank body 32. The guide wall portion 32k guides the excess fuel that has flowed out from the fuel discharge hole 534h of the valve case 53 to the fuel receiving opening 32e. This makes it easier for the excess fuel that has flowed out from the fuel discharge hole 534h of the valve case 53 to return into the subtank body 32.

[0030] The cap portion 530 of the valve case 53 has a cylindrical portion 532 and a lid portion 534. The fuel discharge hole 534h is formed across the boundary between the cylindrical portion 532 and the lid portion 534. Therefore, fuel flowing out from the fuel discharge hole 534h is guided by the lid portion 534 of the cap portion 530, making it less likely to spread axially outward from the cap portion 530. Furthermore, the guide wall portion 32k of the subtank body 32 is formed in an L-shape in plan view. The guide wall portion 32k is positioned so as to extend upward from adjacent vertical wall portions that form corners of the subtank body 32. This makes it easier to mold the guide wall portion 32k.

[0031] Here, the present disclosure is not limited to the above-described embodiment, and modifications are possible within the scope of the present disclosure. For example, in the present embodiment, an example is shown in which the guide wall portion 32k is formed around the fuel receiving opening 32e of the subtank body 32, but it is also possible to omit the guide wall portion 32k by making the opening area of ​​the fuel receiving opening 32e sufficiently larger than the opening area of ​​the fuel discharge hole 534h of the cap portion 530.

Claims

1. A fuel supply device comprising: a sub-tank installed at the bottom of a fuel tank; a fuel pump that guides fuel from inside the fuel tank into the sub-tank and pumps it to an engine; a relief valve that adjusts the pressure of fuel discharged from the fuel pump; and a valve case that is installed on the sub-tank and houses the relief valve, wherein the valve case has a fuel discharge hole that discharges excess fuel that has flowed out from the relief valve, the fuel discharge hole piercing the outer peripheral wall of the valve case, and the fuel discharge hole is positioned so as to face downward and face the fuel receiving opening of the sub-tank.

2. A fuel supply device as described in claim 1, wherein a guide wall portion is formed around the fuel receiving opening of the sub-tank so as to protrude upward, and which guides excess fuel that has flowed out from the fuel discharge hole of the valve case to the fuel receiving opening.

3. A fuel supply device as set forth in claim 1 or 2, wherein the valve case comprises a case main body and a cap part coaxially connected to the case main body, and is arranged so that the axis of the valve case is oriented horizontally, the cap part comprises a cylindrical part and a lid part that closes the tip side of the cylindrical part, and the fuel discharge hole is formed across the boundary between the cylindrical part and the lid part.

4. A fuel supply device as described in claim 2, wherein the fuel receiving opening of the sub-tank is formed on the upper surface of a corner of the sub-tank, and the guide wall portion is formed in a planar L-shape at a position where the adjacent vertical wall portions constituting the corner of the sub-tank are extended upward.

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