JP2629349B2 - Vehicle fuel supply system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vehicular fuel supply device having a sub tank in a fuel tank.

[Prior Art] As a technique of providing a sub-tank in a fuel tank, there is a technique in which a check valve is provided on a lower side (for example, a bottom) of the sub-tank. This check valve is a means to guide the fuel into the sub-tank first, and when the fuel level in the fuel tank is higher than the fuel level in the sub-tank, the fuel in the fuel tank flows into the sub-tank. On the other hand, if the fuel level in the fuel tank is lower than the fuel level in the sub tank, the valve prevents the fuel in the sub tank from flowing out into the fuel tank. .

The sub-tank has a jet pump as a means for pumping fuel into the sub-tank. This jet pump is composed of a return pipe and a pumping pipe, and discharges excess fuel at a high speed from the outlet of the return pipe led to the bottom of the fuel tank. Together, the fuel at the bottom of the fuel tank is guided into the sub-tank via a pumping pipe.

[Problem to be Solved by the Invention] The check valve provided at the bottom of the sub-tank has a slight difference between the liquid level of the fuel tank and the liquid level of the sub-tank (for example, 5 m).
m), it is difficult to ensure perfect sealing. Therefore, when the liquid level in the sub tank is higher than the liquid level in the fuel tank, the fuel in the sub tank leaks little by little from the check valve.

Here, for example, when the fuel in the fuel tank is small,
It is assumed that the vehicle has been parked on a slope for a long time.

The fuel stored in the sub-tank leaks out of the sub-tank from the check valve due to long-term parking.
On the other hand, when the discharge port at the lower end of the return pipe opens above the liquid level due to parking on a slope, the fuel in the return pipe (500-600 cc of fuel between the discharge port and the regulator)
) Will flow out into the fuel tank.

For this reason, it is necessary to fill the return pipe with fuel in order to start the internal combustion engine and discharge fuel from the outlet of the return pipe after parking for a long time on the slope. To fill the return pipe with fuel, 500 to 600 cc of surplus fuel is required, but 500 to 600 cc of fuel does not remain in the sub tank. For this reason, once the internal combustion engine is started, the fuel is not replenished in the sub tank, and the internal combustion engine stops. That is, when the vehicle is parked on a slope for a long time, the internal combustion engine cannot be started.

An object of the present invention is to provide a vehicular fuel supply device that can reliably supply fuel to an internal combustion engine even after a vehicle has been parked on a slope for a long period of time.

Means for Solving the Problems In order to achieve the above object, a vehicle fuel supply device of the present invention employs the following technical means.

The vehicle fuel supply device includes a fuel tank that stores fuel,
A pump disposed in the fuel tank, for pumping fuel to the outside of the fuel tank, a sub-tank provided to cover a lower portion of the pump, and storing fuel sucked into the pump; A check valve is provided, which allows fuel outside the sub-tank to flow into the inside of the sub-tank, and prevents a fuel inside the sub-tank from flowing out of the sub-tank, and a part of the fuel discharged from the pump. A jet pump having a return pipe leading to the bottom of the fuel tank and a pumping pipe for pumping fuel at the bottom of the fuel tank into the sub-tank by fluid energy of fuel discharged from an outlet of the return pipe; And

The return pipe of the jet pump includes a fuel holding valve that is opened at a position upstream of the discharge port when a pressure equal to or more than a predetermined value is applied from upstream to downstream.

[Operation] When the vehicle is parked, the pump stops along with the stop of the internal combustion engine. When the pump stops, the pressure applied to the fuel holding valve of the return pipe disappears. As a result, the fuel in the return pipe is retained in the return pipe for a long time.

When the fuel pump operates, at least the fuel stored in the return pipe is supplied into the sub-tank via the suction pipe.

[Effects of the Invention] As described above, according to the present invention, when the fuel pump operates, at least the fuel stored in the return pipe is supplied to the sub tank. Therefore, even if the inside of the sub-tank is empty due to long-term parking, the fuel in the return pipe is supplied into the sub-tank, and the internal combustion engine can be reliably started.

Example Next, a vehicle fuel supply device of the present invention will be described based on an example shown in the drawings.

(Configuration) FIG. 1 is a sectional view of a vehicular fuel supply device installed in a fuel tank of an automobile.

The fuel supply device for a vehicle is roughly divided into a pump 2 for pumping fuel in a fuel tank 1 to the outside, a sub-tank 3 for covering a fuel inlet of the pump 2, and a jet pump 4 for supplying fuel to the sub-tank 3. It is configured. In addition,
The pump 2, the sub-tank 3, and the jet pump 4 are assembled together with remaining amount detecting means (main parts omitted).

Next, the fuel tank 1, the pump 2, the sub tank 3, and the jet pump 4 will be briefly described.

a) First, the fuel tank 1 will be described.

The fuel tank 1 is a container that joins the upper tank 5 and the under tank 6 and stores fuel such as gasoline therein. In the top plate of the upper tank 5, a hole 7 for inserting the assembled pump 2, sub-tank 3, and jet pump 4 is formed in the fuel tank 1. The hole 7 is closed by a lid 8. In addition, the periphery of the lid 8 is covered with the fuel tank 1 through the sealing material 9.
To keep the inside of the fuel tank 1 airtight.

b) Next, the pump 2 will be described.

The pump 2 is provided inside the sub tank 3. When energized, the pump 2 sucks the fuel at the bottom in the sub-tank 3 through the filter 10 below the pump 2, and passes the sucked fuel through the supporter 11 and the discharge pipe 12 to the outside of the fuel tank 1. This is a non-contact type pump for pumping to
The supporter 11 is made of a resin and has a sub-tank 3 described below.
Is provided integrally with the cover 13. Also discharge pipe
Reference numeral 12 is made of metal and is fixed to the lid 8. The supporter 11 and the discharge pipe 12 are liquid-tight and slidable in the axial direction.

The fuel discharged from the discharge pipe 12 is supplied to a fuel chamber of an internal combustion engine (not shown) via an overfilter 14 and a fuel injection valve 15, as shown in FIG. The pressure of the fuel supplied to the fuel injection valve 15 is adjusted by the regulator 17. In addition, the pump 17
Are connected by a fuel supply pipe 18. Excess fuel that has passed through the regulator 17 is guided again into the fuel tank 1 by the return pipe 19.

The pump 2 is provided with a lead wire 20 for energization, and this lead wire 20 is connected to a connector 21 formed integrally with the lid 8.

c) Next, the sub tank 3 will be described.

The sub-tank 3 is inserted inside a bracket 22 provided integrally with the lid 8, and is slidably supported by the bracket 22 in the vertical direction. The bracket 22 has a vertically extending window 23 at a portion where the sub tank 3 is fitted.
Are formed. The window 23 is fitted with a projection 24 formed around the sub-tank 3 to enable the sub-tank 3 to move up and down within the range of the opening of the window 23.

The sub-tank 3 is a resin container that covers the lower part of the pump 2 and stores fuel sucked into the pump 2 and has a capacity of, for example, about 700 cc. .

A check valve 25 is provided at the bottom of the sub tank 3.
The check valve 25 includes a hole 26 opened at the bottom of the sub tank 3 and an umbrella-shaped rubber valve 27 for opening and closing the hole 26. The valve 27 opens and closes the hole 26 according to the difference between the pressure in the sub tank 3 and the pressure in the fuel tank 1. Specifically, when the liquid level in the sub tank 3 is higher than the liquid level in the fuel tank 1, the fuel tank 1 is closed to prevent the fuel in the sub tank 3 from flowing into the fuel tank 1. Conversely, when the liquid level in the fuel tank 1 is higher than the liquid level in the sub tank 3 by about 5 mm or more, the fuel tank 1 opens to allow the fuel in the fuel tank 1 to flow into the sub tank 3.

A cover 13 is attached to the upper part of the sub tank 3. The cover 13 is provided with a projection 29 formed on the upper end of a joint pipe 28 (a component of the return pipe 19) described below.
And a claw 32 that engages with a protrusion 31 formed on the upper end of the sub tank 3.
By doing so, the cover 13 and the sub tank 3 can be attached and detached. The cover 13 is composed of the cover 13 and the lid 8.
Is urged downward by a spring 33 arranged between them. Thus, even if the length of the fuel tank 1 in the vertical direction is displaced, the expanded rubber 3a mounted on the lower surface of the sub tank 3 comes into contact with the bottom of the fuel tank 1.

d) Next, the jet pump 4 will be described.

The jet pump 4 includes a return pipe 19 that guides excess fuel into the fuel tank 1 and a pumping pipe 34 that guides fuel at the bottom of the fuel tank 1 into the sub-tank 3.

The return pipe 19 is connected to the regulator 17 as described above.
The excess fuel that has passed through is guided into the fuel tank 1. The return pipe 19 in the fuel tank 1 guides the fuel guided into the fuel tank 1 by the return pipe 19 to the bottom of the fuel tank 1. The return pipe 19 in the fuel tank 1 is formed by combining an inflow pipe 35, a joint pipe 28, and an outflow pipe 36.

The inflow pipe 35 is a metal pipe that communicates with the inside and outside of the fuel tank 1 and is fixed to the lid 8. The inflow pipe 35 in the fuel tank 1 extends toward the bottom of the sub tank 3, penetrates through the cover 13 of the sub tank 3, and is inserted into the joint pipe 28. The joint pipe 28 and the inflow pipe 35 are sealed in a liquid-tight manner by an x-ring 37 and are slidable in the axial direction.

The joint pipe 28 is a resin pipe provided with a fuel holding valve 38 according to the present invention at a lower portion, and a lower end is joined to an upper end of the outflow pipe 36 by a joining method such as ultrasonic welding.

The fuel holding valve 38 opens when the pressure of the return fuel exceeds a predetermined pressure (for example, 0.2 to 0.9 kg / cm ² ),
This is a means for guiding the fuel outflow pipe 36. This fuel holding valve 38
Consists of a valve seat 39 formed on the upstream side in the joint pipe 28, a valve body 40 made of resin in a ball shape, a spring 41 for pressing the valve body against the valve seat 39, and a spring holding member 42 for holding the spring 41. . The pressure at which the valve element 40 opens is adjusted by the spring load of the spring 41. Further, the spring holding member 42 has a hole 42a through which fuel passes at the center, and is pressed into the joint pipe 28 and fixed.

The outflow pipe 36 is formed integrally with the sub tank 3, guides the fuel guided from the joint pipe 28 to the lower surface of the sub tank 3, and discharges the fuel along the bottom surface of the fuel tank 1. The fuel discharge port 43 of the outflow pipe 36 is provided in a nozzle shape in order to increase the flow rate of the discharged fuel.

The pumping pipe 34 is a pipe provided with an inflow port 44 which opens at a predetermined distance from the discharge port 43 and opens opposite thereto, and also has an outflow port 45 which opens upward in the sub tank 3.
The pumping pipe 34 includes a passage 46 formed integrally with the sub tank 3 and a passage 48 formed between the pump cover 47 mounted on the bottom of the sub tank 3 and the sub tank 3.

(Operation) Next, the operation of the above embodiment will be briefly described.

When the vehicle is stopped or parked on a flat road surface, if the fuel tank 1 contains a certain amount of fuel, the sub tank 3
The fuel in the fuel tank 1 is supplied into the sub tank 3 from the one-way valve.

When the pump 2 is energized, the pump 2 sucks the fuel in the sub tank 3 and supplies it to the internal combustion engine. Most of the fuel supplied to the internal combustion engine becomes surplus fuel, and is discharged as a high-speed flow from the discharge port 43 via the return pipe 19. Excess fuel blown out from the discharge port 43 is
It flows into the sub tank 3 via 34. Meanwhile, the outlet 43
The fuel flowing into the inflow port 44 of the suction pipe 34 gives fluid energy to the fuel in the fuel tank 1 around the discharge port 43 and the inflow port 44 by the jet flow action, and the fuel is supplied to the fuel tank together with the surplus fuel. The fuel in 1 is guided into the sub-tank 3 through the suction pipe 34. During operation of the pump 2, fuel is supplied into the sub-tank 3 by the action of the jet pump 4.

 Next, the operation according to the present invention will be described.

When the vehicle is parked on a slope for a long time, the fuel tank 1
The fuel level in the inside is low and the outlet of the return pipe 19
When 43 is not immersed in fuel.

Due to the long-term parking, the fuel stored in the sub-tank 3 leaks little by little from the check valve 25, and the fuel in the sub-tank 3 almost flows out to the fuel tank 1. A predetermined amount (for example, around 100 cc) of fuel is provided in the sub-tank 3 so that the fuel can be pumped when the pump 2 starts operating even if the vehicle is parked for a long time.

On the other hand, the fuel in the litter pipe 19 is prevented from flowing out of the return pipe 19 by the fuel holding valve 38 even if the discharge port 43 is not immersed in the fuel. That is, the return pipe 19 between the regulator 17 and the fuel holding valve 38 is filled with fuel.

The fuel supply pipe 18 from the pump 2 to the regulator 17 is prevented from flowing backward by a one-way valve (not shown) provided on the pump 2. For this reason, the fuel supply pipe 18 is filled with the fuel even if the long-term parking is performed on the slope.

After long-term parking on a slope in the above state, that is, in a state where the fuel in the fuel tank 1 is low, the pump 2 is energized. Then, the pump 2 discharges a small amount of fuel in the sub tank 3 toward the internal combustion engine. Since the fuel pipe from the pump 2 to the fuel holding valve 38 is filled with the fuel, the fuel holding valve 38 is opened by the pressure of the surplus fuel that has passed through the regulator 17, and the surplus fuel is discharged to the discharge port 43 and the pumping port 43. It is supplied into the sub tank 3 via a pipe 34. That is, the fuel stored in the return pipe 19 is recovered in the sub-tank 3 almost simultaneously with the energization of the pump 2.

At this time, if the vehicle is moving from sloping ground to level ground,
The fuel in the fuel tank 1 is guided into the sub tank 3 by the operation of the jet pump 4.

(Effects of Embodiment) Since it is not necessary to fill the return pipe 19 with excess fuel as in the related art, it is possible to operate the jet pump 4 (if fuel is present around the discharge port 43) immediately after starting. In addition, even if there is no fuel around the discharge port 43, the fuel discharged from the discharge port 43 can be collected in the sub tank 3 and supplied to the internal combustion engine.

In other words, the fuel in the fuel tank 1 is low, and the startability of the internal combustion engine after long-term parking on a slope is improved as compared with the related art.

(Modification) As shown in the present embodiment, if the pump 2 is of a non-contact type, it is necessary to provide a small amount of fuel in the sub tank 3 even if fuel leaks from the check valve 25. If a contact type pump is used, air can be pumped toward the internal combustion engine, so that there is no need to leave fuel in the sub tank 3.

[Brief description of the drawings]

FIG. 1 is a sectional view of a vehicle fuel supply device, and FIG. 2 is a schematic diagram showing a fuel supply path. In the figure, 1 ... fuel tank, 2 ... pump, 3 ... sub tank, 4 ... jet pump, 19 ... return pipe,
25 ... check valve, 34 ... pumping pipe, 38 ... fuel holding valve

Claims (1)

(57) [Claims] 1. A fuel tank for storing fuel, a pump disposed in the fuel tank for pumping the fuel to the outside of the fuel tank, provided to cover a lower portion of the pump, and drawn into the pump. A sub-tank for storing fuel, a check valve provided below the sub-tank, for allowing fuel outside the sub-tank to flow into the sub-tank, and for preventing fuel inside the sub-tank from flowing out of the sub-tank; A return pipe for guiding a part of the fuel discharged from the pump to the bottom of the fuel tank, and the fuel at the bottom of the fuel tank is supplied to the sub-tank by fluid energy of the fuel discharged from an outlet of the return pipe. And a jet pump having a suction pipe for pumping the fuel into the vehicle. The return pipe Ettoponpu, the position upstream of the outlet, the vehicular fuel supply apparatus characterized by comprising a fuel holding valve opening pressure is applied higher than a predetermined value from the upstream toward the downstream.