JPH0230971A - On-vehicle device for feeding fuel - Google Patents

Abstract

PURPOSE:To prevent fluid from reversely flowing as well as to reduce parts required in number by opening the exhaust port of a jet pump in proximity to the upper end of a sub-tank, and thereby forming the bottom section of the sub-tank with a fluid control device groove consisting of the jet pump. CONSTITUTION:A reverse flow check valve 10 is provided, which prevents fuel from flowing into a fuel tank 1 from a sub-tank 6 provided for a fuel intake. A fuel exhaust port 39 of a jet pump 30 is opened in proximity to the upper end of the sub-tank 6. And the bottom section of the sub-tank 6 is formed with a fluid control device groove consisting of the jet pump 30. This constitution thereby prevents fuel in the sub-tank 6 from reversely flowing into the fuel tank 1 even when a fuel pump 11 is suspended, thereby making it possible to reduce parts required in number so as to make the constitution itself simple.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vehicle fuel system in which a fuel pump is installed in a fuel tank mounted on a vehicle, and the fuel pump supplies fuel in the fuel tank to an engine, etc. Regarding the supply device.

[Conventional technology]

Install the fuel pump inside the fuel tank mounted on the vehicle,
In a fuel supply system that uses a fuel pump to supply fuel in a fuel tank to a vehicle engine, the fuel level in the fuel tank may drop, or the liquid level may fluctuate or tilt. When there is a shortage of fuel around the intake port of the fuel pump, air is sucked into the fuel pump, causing a so-called breathing phenomenon, which hinders the smooth supply of fuel to the engine.

In order to prevent such problems, conventionally, a sub-tank was installed on the bottom of the fuel tank, a fuel pump was housed in this sub-tank, and the bottom wall of this sub-tank was connected to the inside and outside of the sub-tank to allow fuel to flow from the fuel tank into the sub-tank. A fuel supply device has been proposed in which a fuel intake port is provided, and a check valve is provided in the fuel intake port to prevent fuel from flowing backward from the sub-tank side to the fuel tank side.

According to this, since the sub-tank and the fuel tank are electrically connected through the fuel intake hole formed in the bottom wall of the sub-tank, the fuel liquid level in the sub-tank can be made equal to the fuel liquid level in the fuel tank.

However, with this method, it is difficult to raise the fuel level in the sub-tank higher than the fuel level in the fuel tank and collect the fuel in the sub-tank.

For this reason, a part of the fuel discharged from the discharge port of the fuel pump is returned to the sub-tank through a fuel return pipe, and this fuel return pipe is connected to a fuel discharge port opened in the sub-tank and to the fuel tank. Consideration and research has been made to install a jet pump that connects the fuel suction port and sucks the fuel in the fuel tank from the fuel suction port using the fluid energy of the fuel flowing from the fuel return pipe through the fuel discharge port. has been done.

According to this document, the fuel in the fuel tank can be forcibly sucked into the sub-tank by the jet pump, and the fuel level in the sub-tank can therefore be made higher than the fuel level in the fuel tank. This has the advantage of preventing air from being sucked in through the pump's intake port, and even if the remaining amount of fuel in the fuel tank becomes low, the fuel can be collected in the sub-tank and efficiently supplied to the engine without waste.

[Problem to be solved by the invention]

However, in the above-mentioned jet pump, if the fuel pump stops, there is a concern that the fuel in the sub-tank may flow back into the fuel tank from the fuel discharge port through the fuel suction port. Providing a prevention valve is being considered.

However, providing such a non-return valve not only increases the number of parts, but even if the valve opening pressure is lowered, pressure loss will occur, impairing the jet pump's functionality, and there is concern that the performance of the jet pump will deteriorate. There is.

In the present invention, there is no need to provide a check valve at the fuel discharge port of the jet pump, and even if the fuel pump stops, the fuel in the sub-tank is prevented from flowing back into the fuel tank from the fuel discharge port through the fuel suction port. The present invention aims to provide a fuel supply system for a vehicle.

[Means to solve the problem]

In order to achieve the above object, the first aspect of the present invention is to accommodate a sub-tank in a fuel tank mounted on a vehicle, which can store fuel at a higher liquid level than the fuel level of the fuel tank, and to attach the sub-tank to the bottom wall of the sub-tank. A fuel intake port is provided for introducing the fuel in the fuel tank into the sub-tank, and a backflow prevention valve is provided in the fuel intake port to prevent the fuel in the sub-tank from flowing out into the fuel tank. A fuel pump having an inlet opening near the bottom wall of the sub-tank and a discharge outlet connected to a fuel supply pipe is accommodated, and a part of the fuel discharged from the discharge outlet of the fuel pump is transferred using a fuel return pipe. The fuel return pipe has a fuel discharge port opened in the subtank and a fuel suction port opened in the fuel tank, and the fuel return pipe and the fuel discharge In a vehicle fuel supply system connected to a jet pump that sucks fuel in a fuel tank from the fuel suction port using the fluid energy of the fuel flowing through the outlet, the fuel discharge port of the jet pump is opened near the upper end of the sub-tank. It is characterized by

The second aspect of the present invention is characterized in that the shet pump is constituted by a groove forming a planar fluid element, and the liquid groove is formed at the bottom of the sub-tank.

[Effect]

According to the first aspect of the present invention, since the fuel discharge port of the jet pump is opened near the upper end of the sub-tank, even if the fuel pump stops, the fuel in the sub-tank can remain up to the height of the fuel discharge port at most. This prevents backflow into the fuel tank.

Moreover, since this device does not require a check valve, the number of parts can be reduced, and the maintenance and other troubles associated with installing a check valve can be avoided.

Further, according to the second aspect of the present invention, since the fluidic element groove constituting the jet pump is formed at the bottom of the sub-tank, the number of parts can be reduced and the configuration can be simplified.

〔Example〕

The present invention will be described below based on an embodiment shown in the drawings.

In the figure, 1 is a fuel tank mounted on a vehicle body, and has a ceiling surface 1a, a side surface 1b, and a bottom IC. An opening 2 is formed in the ceiling surface 1a of the fuel tank 1.
A cover 3 is removably attached to the opening 2 using fixing screws (not shown) or the like. Note that a seal packing 4 is interposed between the cover 3 and the fuel tank 1.

The cover 3 is made of high-density polyethylene or polyacetal, and is integrally formed with the bracket 5.

This bracket 5 extends downward from the cover 3 and fixes the sub-tank 6.

The sub-tank 6 is made of high-density polyethylene, polyacetal, or the like, and has a cylindrical shape with a bottom extending toward the bottom IC of the fuel tank 1, and is open at the top end. Inside the fuel tank 1, the sub-tank 6 has a bottom wall 6C in contact with the bottom IC of the fuel tank 1 via a cushion material 7, and therefore the load of the sub-tank 6 is mainly applied to the fuel tank 1. It is supported by the bottom IC of 1.

Furthermore, a locking pawl 6b is protruded from the upper side wall of the sub-tank 6, and this locking pawl 6C fits into a locking slit 5a formed in the bracket 5, thereby preventing the sub-tank 6 from moving in the horizontal direction. However, vertical movement is allowed.

A bottom plate 8 shown in FIG. 3 is fitted to the bottom wall 6c of the sub-tank 6 to form a double bottom structure, and the bottom plate 8 and the bottom wall 6C of the sub-tank 6 are penetrated to connect the fuel tank 1 and the sub-tank. A fuel intake port 9 is formed that conducts the inside of the fuel tank 6 . Therefore, the fuel in the fuel tank 1 flows into the sub-tank 6 through this fuel intake port 9.

The fuel intake port 9 is provided with a check valve 10 that prevents the fuel in the sub-tank 6 from flowing out into the fuel tank 1.

This check valve 10 is attached to the bottom plate 8 and is made of rubber such as fluorosilicone or PPS.
It is formed into an umbrella shape (mushroom shape) by baking a rubber material such as fluorine onto a resin material such as , NY, etc., and even if the fuel liquid level in the fuel tank 1 is extremely small, the fuel liquid level in the sub tank 6 In other words, if the pressure on the fuel tank 1 side becomes even slightly higher, the valve opens and the pressure on the fuel tank 1 side increases.
The valve opening pressure is set such that fuel can be introduced into the sub tank 6.

A fuel pump 11 is housed within this sub-tank 6.

In this fuel pump 11, the lower end of the pump case is supported by a cushion material 12.
is supported by support ribs 6e formed on the sub-tank 6. Therefore, the fuel pump 11 is
It is supported by the sub-tank 6 via.

The fuel pump 11 is provided with a suction port 13 at its lower end, and this suction port 13 extends below the cushion material 12 and is close to the bottom surface 6C of the sub-tank 6.

A fuel filter 14 is provided at the intake port 13 of this fuel pump 11.
is connected. The fuel filter 14 may be a mesh filter, but it is one that can be impregnated with fuel by capillary action, such as a twill filter, and if even a part of it is immersed in fuel, the filter will be damaged due to surface tension. It is preferable that the parts that are wet and exposed to the air are also sealed by the wet fuel.

It should be noted that a gap of about 1 inch is ensured between the lower surface of the fuel filter 14 and the bottom IC of the sub-tank 6.

The fuel pump 11 is provided with a discharge port 15 at its upper end, and a fuel supply pipe 16 is connected to the discharge port 15.

This fuel supply pipe 16 is connected to the engine, and a connecting cylinder portion 18 formed on the support 17 is used to connect the discharge port 15 to the fuel supply pipe 16.

That is, the support 17 has the function of a lid that covers the upper end opening of the sub-tank 6, and is made of high-density polyethylene, polyacetal, or the like. This support 1
7 is integrally formed with the connecting cylinder portion 18 at the center thereof. The discharge port 15 of the fuel pump 11 is fitted into the lower end opening of the connecting cylinder 18, and is kept liquid-tight by a packing 19.

Further, the lower end of the fuel supply pipe 16 is fitted into the upper end opening of the connecting cylinder portion 18, and is kept liquid-tight by the X ring 20 and the cap 21.

Therefore, the discharge port 15 and the fuel supply pipe 16 are electrically connected to each other via the connecting cylinder portion 18 formed in the support 17.

The fuel supply pipe 16 passes through the cover 3 and connects to the fuel tank 1.
The fuel is led out to the outside, and is designed to supply fuel to an engine (not shown). This engine has a pressure regulator that returns branched fuel to the fuel return pipe 22. The fuel return pipe 22 penetrates the cover 3 and is introduced into the fuel tank 1.

Note that the fuel return pipe 22 may branch directly from the fuel supply pipe 16 outside the fuel tank 1.

The fuel supply pipe 16 and the fuel return pipe 22 are each fluid-tightly attached to the cover 3 by O-rings 23.23, and these O-rings 23.23 are supported by a resin holding plate 24.24. ing.

These presser plates 24, 24 are fixed to the cover 3 by heat caulking the cover 3.

Holding plate 24 into which the fuel supply pipe 16 is inserted
and a support 17 that covers the upper end opening of the sub-tank 6.
A spring 25 is hung between the connecting tube portion 18 and the connecting tube portion 18. This spring 25 is the sub tank 6
is pushed downward with a force of, for example, 2 to 7 kg,
This prevents the sub-tank 6 from floating and vibration.

Furthermore, a connector fixing hole 26 is opened in the cover 3, and a connector 27 is fitted into this fixing hole 26. This connector 27 is fixed to the cover 3 by hot caulking the upper end of the cover 3, and is kept liquid-tight with an O-ring 28.

This connector 27 is connected to the fuel pump 11 by a cord 29, and is electrically connected to an external power source.

The fuel return pipe 22 passes through the support 17 and is introduced into the sub-tank 6, and is connected to the jet pump 30 within the sub-tank 6.

A fuel return passage 31 is integrally formed in the inner wall surface of the sub-tank 6, and the fuel return pipe 22 is connected to this fuel return passage 31.

The lower end of the fuel return passage 31 communicates with a fuel introduction head 33 of a jet pump 30 formed at the bottom of the sub-tank 6.

As shown in FIG. 3, the jet pump 30 is formed by a planar fluid element type groove 32. As shown in FIG.

This fluidic element type groove 32 is formed on the lower surface of the bottom wall 6c of the sub-tank 6, and is configured as a passage by covering this lower surface with the bottom plate 8.

This fluid element type groove 32 is connected to a fuel introduction head 33 with which the lower end of the fuel return passage 31 is connected, and this fuel introduction head 3
3, a branch introduction section 35, 35 and a day user part 36 following this nozzle section 34.
It is made up of.

The branch introduction portions 35.35 each communicate with fuel inlets 37.37 formed in the bottom plate 8, and these fuel inlets 3
The fuel in the fuel tank 1 can be sucked through 7.37.

Further, the downstream end of the day user portion 36 is connected to the fuel discharge passage 3.
It leads to 8. This fuel discharge passage 38 is connected to the sub tank 6
It is integrally formed on the inner wall surface of the fuel tank, and three fuel discharge ports are opened at the upper end. The fuel discharge port 39 is located at the upper part of the sub-tank 6 and opens upward, and opens at a distance of, for example, about 5 mz from the lower surface of the support 17 that covers the upper end opening of the sub-tank 6.

In FIG. 1, 40 is a blind stopper that closes the end of the fuel introduction head 33, and 45 is a fuel supply port that supplies fuel to the fuel tank 1.

Furthermore, in FIG. 2, reference numeral 50 denotes a capacitance type fuel sender assembly that detects and outputs the fuel level in the sub-tank 6; It is worn.

The operation of an embodiment of such a configuration will be explained.

Fuel is supplied to the fuel tank 1 mounted on the vehicle from a fuel supply port 45. The fuel in fuel tank 1 is connected to the bottom IC
When the fuel pressure reaches about 15 to 20 mrn, the check valve 10 is opened by this fuel pressure, and the fuel in the fuel tank 1 flows into the sub tank 6 through the fuel intake port 9.

Therefore, at least fuel tank 1 is included in sub tank 6.
The fuel is stored at a liquid level equivalent to the liquid level of .

Therefore, the fuel filter 14 connected to the suction port 13 of the fuel pump 11 is immersed in fuel.

When the fuel pump 11 is operated in such a state, the fuel in the vicinity of the bottom surface 6C of the sub-tank 6 is filtered by the fuel filter 14 and sucked in from the suction port 13, and is pressurized to the discharge port 1.
Discharge from 5. This discharged fuel is supplied from the connecting cylinder portion 18 to the engine of the vehicle through the fuel supply pipe 16.

A well-known pressure regulator (not shown) is provided on the engine side of the vehicle, and surplus fuel is returned to the fuel tank 1 side through the fuel return pipe 22 by adjusting the pressure with this pressure regulator.

The fuel returned to the fuel tank 1 side through the fuel return pipe 22 is supplied to the jet pump 30 via a fuel return passage 31 in the sub-tank 6.

In the jet bomb 30, the fuel return passage 3
The fuel sent from 1 is supplied to the fuel introduction head 33 and is injected into the day user part 36 through the narrow nozzle part 34. At this time, a strong negative pressure is generated at the lower end of the nozzle part 34, and the fuel in the fuel tank 1 is sucked in from the fuel suction port 37.37 formed in the bottom plate 8 via the branch introduction part 35.35.

The fuel that has been forcibly sucked in in this way passes through the daylight user section 36, passes through a fuel discharge passage 38 communicating with the downstream end of the daytime user section 36, and is discharged into the sub-tank 6 from the fuel discharge port 39 at the upper end.

The fuel supplied into the sub-tank 6 is transferred to the cushion material 12
passes through and collects at the bottom of the sub-tank, and this sub-tank 6
Raise the liquid level inside.

Therefore, when the fuel pump 11 is operated to supply fuel to the engine side, the jet pump 30 can forcibly pump up the fuel in the fuel tank 1 into the sub-tank 6. The fuel level within the fuel tank 1 can be ensured higher than the fuel level within the fuel tank 1.

Therefore, even if the fuel in the fuel tank 1 runs out or the fuel level is tilted due to the vehicle tilting or sudden start, the fuel pump 11 will continue to supply fuel to the engine because the fuel level in the sub-tank 6 is high. be able to.

On the other hand, when the operation of the fuel pump 11 is stopped, the fuel intake port 9 formed at the bottom of the sub-tank 6 is connected to the backflow prevention valve 1.
0, so fuel will not flow out from the sub-tank 6 side to the fuel tank 1 side.

Furthermore, after the fuel pump 11 is stopped, there is a risk that the fuel in the sub-tank 6 will flow back to the fuel tank 1 side from the suction port 37, 37 through the fuel discharge port 39 of the jet pump 30, but the three fuel discharge ports Since it is opened at the upper end of the sub-tank 6, even if the fuel on the upper surface may escape from these three fuel discharge ports, the fuel on the lower surface will not escape from this fuel discharge port 39. That is, subtank 6
The fuel inside is prevented from escaping from the fuel discharge port 39,
The liquid level height up to the opening surface of the maximum fuel discharge port 39 can be ensured.

Therefore, even if the operation of the fuel pump 11 is stopped, fuel can be stored in the sub-tank 6 at a liquid level higher than the fuel liquid level on the fuel tank 1 side.

Therefore, even if the fuel level is low, or if you park on a slope or slope and start the engine with the liquid level tilted, the remaining fuel in the sub-tank 6 can be sucked in. , allowing the engine to start.

In such an embodiment, since the fuel discharge port 39 of the jet pump 30 is opened at the upper end of the sub-tank 6,
The fuel in the sub-tank 6 does not escape into the fuel tank 1 through this fuel discharge port 39, and therefore there is no need to install a special check valve on this fuel discharge port 39.

Therefore, the number of parts can be reduced, and the maintenance and other troubles associated with installing a check valve can be avoided.

Furthermore, there is no pressure loss caused by installing a check valve, and the performance of the jet pump is improved.

In addition, in the above embodiment, the planar fluidic element type groove 32 of the jet pump 30 is formed in the bottom wall 6C of the sub-tank 6, so this position is easy to process and is also a dead space. It is possible to secure a larger capacity in the sub-tank 6 than in the case where the sub-tank 6 is used.

Furthermore, since the fluid element type groove 32 is formed in the bottom wall 6c of the sub-tank 6 and is covered with the bottom plate 8, the number of parts can be reduced. 32 can be integrally molded, so no effort is required for processing.

In the present invention, the fluid element type groove 32 may be formed on the bottom plate 8 side.

〔Effect of the invention〕

As explained above, according to the first aspect of the present invention, since the fuel discharge port of the jet pump is opened near the upper end of the sub-tank, even if the fuel pump stops, the fuel in the sub-tank can be discharged up to the height of the fuel discharge port. This will prevent it from flowing back into the fuel tank. Moreover, since this device does not require a check valve, the number of parts can be reduced, and the maintenance and other troubles associated with installing a check valve can be avoided.

Further, according to the second aspect of the present invention, since the fluidic element groove constituting the jet pump is formed at the bottom of the sub-tank, the number of parts can be reduced and the configuration can be simplified.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a cross-sectional view of a fuel tank, FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line ■-■ in FIG. It is an arrow view. 1...Fuel tank, 3...Cover 5...Bracket, 6...Sub tank, 6a...Bottom, 8...
Bottom plate, 9... fuel intake, 10... backflow prevention valve,
11...fuel pump, 13...intake port, 14...
Fuel filter, 15...Discharge port, 16...Fuel supply pipe, 22...Fuel return pipe, 30...Jet pump, 31...Fuel return passage, 32...Planar fluid element type Groove, 33... Fuel introduction head, 34... Nozzle part, 35... Branch introduction part, 36
...Diff user part, 37...Suction port, 38...
・Fuel release passages, 3...Fuel release ports. Applicant's agent Patent attorney Takehiko Suzue

Claims (2)

[Claims] (1) A fuel tank mounted on a vehicle, a sub-tank housed in this fuel tank and capable of storing fuel at a liquid level higher than the fuel level in the fuel tank, and a sub-tank installed on the bottom wall of this sub-tank and stored in the fuel tank. A fuel intake port for introducing fuel into the sub-tank, a backflow prevention valve installed in the fuel intake port to prevent the fuel in the sub-tank from flowing out into the fuel tank, and a backflow prevention valve installed inside the sub-tank so that the intake port a fuel pump that is opened near the bottom wall of the sub-tank and has a discharge port connected to a fuel supply pipe; and a fuel return pipe that returns a portion of the fuel discharged from the discharge port of the fuel pump toward the sub-tank. , has a fuel discharge port connected to the fuel return pipe and opened into the sub-tank, and a fuel suction port opened into the fuel tank, and the fluid energy of the fuel flowing through the fuel return pipe and the fuel discharge port causes the above-mentioned 1. A fuel supply device for a vehicle, comprising a jet pump that sucks fuel in a fuel tank from a fuel suction port, and a fuel discharge port of the jet pump is opened near an upper end of a sub-tank. (2) The vehicle fuel supply system according to claim 1, wherein the jet pump includes a groove forming a planar fluid element, and the groove is formed at the bottom of the sub-tank.