JPH0396653A - Fuel supply device - Google Patents

Abstract

PURPOSE:To control vapor generation inside a main tank by preferentially introducing high temperature fuel excluded low boiling point component from an engine to a suction port of a fuel pump, in a fuel supply device arranged at the inside of a fuel tank of a vehicle and the like. CONSTITUTION:A filter chamber 8 below a sub-tank 6 arranged at a substantial center of a main tank 2 is arranged, and the fuel inside the filter chamber 8 is sucked from a suction port 23 with activation of an motor-driven fuel pump 20 and pressure-supplied to an engine. The fuel which is pressure-supplied to an engine and not consumed, is returned to the sub-tank by a return pipe 12. In a fuel supply device, when a fuel liquid face of the sub-tank 6 exceeds a specified value, a first float type opening/closing valve 30 by which the fuel is supplied to the filter chamber 8 is provided. When a fuel level inside the filter chamber 8 is lower than a predetermined level, a second float type opening/closing valve 40 which communicates the sub-tank with the filter 8 is provided.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fuel supply system installed in a fuel tank of a vehicle, etc.
Regarding the N position, the present invention relates to a fuel supply device that can pump a constant amount of fuel to the engine side without being affected by fluctuations in fuel level, and that is particularly equipped with measures to suppress fuel vaporization.

[Prior Art] A fuel supply i! installed in a vehicle's fuel tank. When the amount of fuel in the fuel tank is low and the vehicle accelerates suddenly, or when the fuel is tilted to one side of the fuel tank due to driving around a curve or slope, a certain amount of fuel is supplied to the engine. Measures are being taken to ensure that fuel is supplied.

This countermeasure was published in Special Publication No. 47-21843 @ Publication No. 61.
It is shown in, for example, Japanese Patent No.-58678.

The prior art will be explained below based on these.

The invention described in Japanese Patent Publication No. 47-21843 consists of two centrifugal pumps (first bomb, second pump) arranged in series with respect to the suction direction, and a fuel pump installed between the two centrifugal pumps. It consists of a sub-tank that functions to store
The top of the sub-tank is provided with an opening that communicates with the inside of the main tank. Additionally, fuel that is not consumed by the engine and is returned to the engine flows into the main tank via a return vibe.

The first bomb sucks the fuel in the main tank and pumps it into the sub-tank, and the second pump sucks the fuel in the sub-tank and pumps it to the engine. Here, the first pump is designed to have a higher ability to pump fuel than the second pump.

Therefore, the difference between the amount of fuel pumped into the sub-tank by the first pump and the amount of fuel pumped into the engine by the second pump is stored in the sub-tank. As mentioned above, there is an opening at the top of the sub-tank that communicates with the main tank, so when the fuel in the sub-tank reaches the level of the opening, the fuel passes through this opening and flows into the main tank. It will be returned.

For this reason, the sub-tank is always filled with a certain level of fuel, and even if the first pump is temporarily exposed above the fuel level and cannot suck in fuel, the fuel in the sub-tank will be supplied to the engine by the second bomb. This prevents engine troubles due to fuel shortage.

Next, the configuration of the invention described in Japanese Utility Model Application Publication No. 61-58678 is the same as that of the invention described in Japanese Patent Publication No. 47-21843, but also has a structure in which the fuel not consumed by the engine is returned to the sub-tank via a return vibrator. It is something.

The fuel returned from the engine is the fuel from which high-temperature, low-boiling point substances have been removed, and this fuel is returned to the sub-tank by the return pipe, and is again pumped to the engine by the second bomb along with the fuel pumped up from the main tank. be done.

[Problem to be solved by the invention] However, according to these methods, first of all,
In the case of the invention described in Publication No. 21843, the high temperature fuel that is sent to the engine and returned without being consumed flows directly into the main tank, so the low temperature fuel in the main tank is warmed by the high temperature fuel and the low boiling point components is evaporated and Beba is generated as a polyacid. Therefore, it is necessary to take measures such as turning the vapor processing device into a doll.

In addition, after the engine has stopped, the fuel inside the pump turns into vapor due to the heat of the fuel pump itself, and this vapor flows into the filter chamber from the fuel pump's suction port and remains there, allowing the engine to be restarted. Sometimes there is also the problem of the fuel pump running dry.

Next, in the case of the device described in Japanese Utility Model Application Publication No. 61-58678, the high-temperature fuel returned from the engine flows into the sub-tank and is pumped back to the engine by the second bomb.
Said high temperature! ! The water does not flow directly into the main tank.

Therefore, the amount of vapor generated in the main tank is reduced.

However, when the sub-tank is filled with fuel and high-temperature fuel from the engine flows in, this high-temperature fuel flows out from the upper opening of the sub-tank into the main tank. This warms the low-temperature fuel in the main tank, causing vapor to occur in the main tank.

In addition, after the engine has stopped, the fuel inside the bomb is vaporized by the heat of the fuel bomb itself, similar to the invention described in Japanese Patent Publication No. 47-21843, and the engine is restarted.
There is also the problem of the fuel pump running dry.

The present invention is based on the above findings, and firstly, even if the fuel level is tilted due to acceleration or the like when there is little fuel in the main tank, a constant amount of fuel can be pumped to the engine without being affected by this. Furthermore, by preferentially pressure-feeding the high-temperature fuel returning from the engine to the sub-tank to the engine again, the high-temperature fuel is prevented from flowing into the main tank, and the low-temperature fuel in the main tank is suppressed from turning into vapor. Another problem to be solved is to prevent the vapor generated by the heat of the fuel bomb from accumulating in the filter chamber after the engine has stopped, thereby preventing air from being pumped into the fuel bomb and improving high-temperature restart characteristics. It is.

[Means for Solving the Problems] The above problems are solved by a fuel supply device having the following structure.

The fuel supply device is mounted on an object that is subject to acceleration and has a main tank that stores fuel.

Furthermore, it has a sub-tank provided within the main tank.

Furthermore, it has a filter chamber provided below the sub-tank and communicated with the main tank via a filter.

Furthermore, it has a fuel bomb that supplies the fuel in the filter chamber to the engine.

Furthermore, it has a return passage for returning unconsumed fuel supplied to the engine to the sub-tank.

Further provided between the sub-tank and the filter chamber,
The 131st! maintains the fuel level in the sub-tank at a predetermined value, and supplies the fuel in the sub-tank to the filter chamber when the fuel level exceeds the predetermined value! ! have a means of communication.

Further provided between the sub-tank and the filter chamber,
A second communication means is provided for allowing communication between the sub-tank and the filter chamber when the level of fuel in the filter chamber falls below a predetermined level.

[Function] In the fuel supply device having the above means, high-temperature fuel returned from the engine is supplied to the sub-tank through the return passage. This high-temperature fuel is stored in the sub-tank up to a predetermined level, but if it exceeds the predetermined level, the
The communication means allows water to flow from the sub-tank into the filter chamber. Furthermore, the low temperature fuel in the main tank is supplied to the filter chamber after passing through the filter. The fuel in the filter chamber is then pumped to the engine by a fuel bomb.

Here, since the fuel supplied from the sub-tank to the filter chamber does not pass through the filter, there is less pressure loss during passage than with low-temperature fuel supplied from the main tank. Therefore, fuel supplied from the sub-tank is preferentially drawn into the fuel pump, and the shortage is made up with low-temperature fuel supplied from the main tank. As described above, the fuel supplied from the sub-tank is high-temperature fuel returned from the engine, and this high-temperature fuel is preferentially pumped to the engine via the filter chamber. Therefore, high temperature fuel returning from the engine does not flow into the main tank.

Further, after the engine is stopped, the fuel inside the pump may turn into vapor due to the heat of the fuel pump itself, and this vapor may flow back into the filter chamber from the suction port of the fuel bomb and accumulate there. In such a case, when the fuel level in the filter chamber falls below a specified level, the second communication means is operated to allow the fuel in the sub-tank to flow into the filter chamber, thereby preventing the fuel pump from pumping air.

In addition, if the fuel level in the filter chamber falls below the specified level due to acceleration, etc. being applied to the vehicle when fuel is low, the fuel level in the filter chamber becomes tilted in one direction. of fuel flows into the filter chamber, preventing the fuel pump from emptying.

[Example] Examples will be specifically described below with reference to the drawings.

FIG. 1 is an overall view of the installation of a fuel supply system according to the present invention, and FIG. 2 shows a first embodiment of the present invention.

2 in the diagram is the main tank and engine (not shown)
fuel is stored to be pumped to

A sub tank 6 is installed approximately in the center of the main tank 2. The sub-tank 6 stores fuel that is pumped to the engine and is returned without being consumed, and fuel that is pumped up from the filter chamber 8 by a method to be described later. Here, the sub-tank 6 itself is fixed to the flange iron plate 3 with bolts a
3, the seven-lunge iron plate 3 is fixed to the main tank 2 with bolts and nuts via the gasket 4. As the material for the subtank 6, polyamide resin, polyacetal resin, etc. are preferably used.

A filter chamber 8 is repositioned below the sub-tank 6. The filter chamber 8 is a room divided by a planar filter 9 (see Fig. 2) installed almost parallel to the bottom surface of the main tank 2, a wall surface perpendicular to the filter 9, and a wall surface facing the filter 9. The function is to filter the fuel in tank 2,
It functions to store fuel supplied from sub-tank 6, which will be described later.

The fuel in the filter chamber 8 is then sucked into the electric fuel pump 20 and pumped to the engine.

Here, the filter 9 is made of nylon thread, which has a twill weave shape. The weft yarns are a bundle of 34 silk yarns equivalent to 210 denier, woven into each inch of width, and 46 yarns, and the warp yarns are 163 220 denier yarns, which are woven into each inch of width. Therefore, this filter 9 has excellent fuel retention ability, and the fuel inside will not flow back into the main tank 2 when the upper part of the filter chamber 8 is not open. Further, the wall surface of the filter chamber 8 is made of polyamide resin.

The electric fuel bomb 20 is submerged in the sub tank 6, and two Wesco type bombs (first bomb 21 and second bomb 21)
2 in which the pumps 22) are connected in series with respect to the flow direction.
It is a stage bomb. Furthermore, the fuel suction port 23 communicates with the filter chamber 8 through the bottom surface of the sub-tank 6 .

Cushion rubber 24 is interposed in the penetrating portion in consideration of sealability and earthquake resistance.

The fuel suction port 23 slightly protrudes into the inside of the filter chamber 8 so as not to suck in air bubbles that may accumulate in the upper part of the filter chamber 8. Also, the fuel discharge port 2 of the electric fuel pump 20
5 is a fuel supply vibe 1 for supplying fuel to the engine
0 with a rubber hose 13 in consideration of earthquake resistance and compatibility. The fuel discharge port 25 and the connection point between the fuel supply vibrator 10 and the rubber hose 13 are firmly fixed with a clip 15.

Unconsumed fuel that has been pumped to the engine by the electric fuel pump 20 is returned to the sub-tank 6 by the return pipe 12. Here, the tip of the pipe of the return vibe 12 located inside the sub-tank 6 is sloped so that the fuel flows along the wall surface. Therefore, the fuel quietly flows into the sub-tank 6, and bubbling of the fuel in the sub-tank 6 is suppressed.

In the figure, 26 is a vapor discharge hole for discharging the vapor in the bomb chamber of the first bomb 21.
A portion of the fuel and vapor sucked into the filter chamber 8 are then released into the sub-tank 6.

The electric fuel pump 20 is equipped with a relief valve 27. The relief valve 27 is located at the end of a flow path that branches off from the middle of the flow path 21a that connects the first bomb 21 and the second bomb 22, and is located at the end of a flow path that branches off from the middle of the flow path 21a that connects the first bomb 21 and the second bomb 22. A portion of the fuel in the flow path 21a is sometimes released into the sub-tank 6.

Generally, when an engine is started at a low temperature, the battery voltage is low, so the motor rotates at a low speed and the fuel cylinder capacity also decreases. However, the pressure of the fuel pumped to the engine is
If the pressure is not higher than the specified pressure, the fuel will not be injected and the engine will not start.

Therefore, the fuel pump is designed to ensure a specified discharge pressure even when the battery voltage is low. For this reason, when the battery voltage becomes normal after the engine has warmed up, the pump capacity will be more than necessary, and the relief valve 27 will divert the fuel in the flow path 21a into the sub-tank 6 in order to reduce the bomb load. It releases it.

A first float type on-off valve 30 is provided within the sub-tank 6. The first valve 0-1 set on-off valve 30 is the sub tank 6
This is the first communication means that communicates the sub-tank 6 and the filter chamber 8.

The first float type on-off valve 30 includes a valve body 31, a float 32,
It is equipped with a wire 33 and a flow path 36 that communicates between the sub tank 6 and the filter v8, the float 32 and the valve body 31 are housed in the float guide 34 and the valve guide 35 in the sub tank 6, and the flow path 36 is connected to the sub tank 6. It is shaped at the bottom of the.

Here, when the fuel level in the sub tank 6 decreases, the float 32 descends, but when the fuel decreases below a predetermined level, that is, below the position of the float guide 34, the stopper 38 fixed to the upper part of the float 32 moves to the float guide 34.
4, and the descent of the float 32 is stopped.

As shown in the figure, the float 32 is connected to the valve rest 31 by a wire 33, and the length of the wire 33 is at the lower limit of the float 32, that is, when the stopper 38 of the float 32 is in contact with the seven-port guide 34. At this position, the valve rest 31 is adjusted to a length that allows the flow path 36 to be fully closed. Therefore, when the fuel level in the sub-tank 6 is lower than a predetermined level, the flow path 36 is closed by the valve break 31.

Conversely, when fuel is supplied into the sub-tank 6 and exceeds a predetermined level, the float 32 rises and the valve body 31 is gradually closed, allowing the fuel in the sub-tank 6 to pass through the flow path 36 and enter the filter v8. Inflow.

Here, since the fuel is guided from the bottom of the sub-tank 6 to the filter chamber 8, air bubbles do not flow into the filter chamber 8.

A second float type on-off valve 40 is provided within the filter chamber 8 . This second float-type on-off valve 40 is for guiding the fuel in the sub-tank 6 to the filter chamber 8 when the fuel level in the filter chamber 8 decreases, and is a second float valve that communicates the filter chamber 8 and the sub-tank 6. Functions as a means of communication.

The second float type on-off valve 40 includes a valve body 41, a float 42,
It is equipped with an arm part 43 and a flow path 46, and the flow path 46 is connected to the sub tank 6.
It is provided at the bottom of the tank and allows communication between the sub-tank 6 and the filter chamber 8. Further, the arm portion 43 is attached to a support portion 45 fixed to the bottom surface of the sub-tank 6 via a shaft portion 44, and is rotatable in the vertical direction within the filter chamber 8 around the shaft portion 44. is in a state. A float 42 is attached to the free end of the arm 43, and a valve body 41 is fixed between the float 42 and the shaft 44 so as to face the flow path 46. Here, the diameter of the flow path 46 is set to a size that allows passage of more fuel than the fuel ant sucked by the electric fuel pump 20. Furthermore, the float 42 is located approximately at the center of the filter chamber 8 in plan view, and therefore, even if the fuel level is tilted in any direction, front, back, left, or right, the timing of its operation remains almost constant.

When the filter chamber 8 is filled with fuel, the valve body 41 moves onto the float 42 using the lever principle using the shaft portion 44 as a fulcrum.
The channel 46 is closed by wrapping it from below and pushing it under the upward force caused by the buoyancy of the channel 46 . This situation is shown in FIG. Note that a sealing rubber is baked onto a portion of the valve body 41 surrounding the flow path 46.

Next, when the fuel level in the filter chamber 8 decreases, the float 42 moves downward in accordance with the fuel level, and therefore the valve body 4 which is temporarily suspended via the float 42 and the arm 43
1 is also displaced downward, and the flow path 46 is released. As a result, the fuel in the sub-tank 6 flows into the filter chamber 8, and the electric fuel bomb 20 is prevented from emptying. In this embodiment, the fuel suction port 2 of the electric F11 fuel bomb 20 is
The second float-type on-off valve 40 is adjusted to operate at a level where the valve 3 is not exposed from the fuel liquid level.

Next, the overall flow of fuel will be explained.

The electric fuel pump 20 sucks the fuel in the filter chamber 8 . Here, if the fuel in the sub-tank 6 is empty, no fuel is supplied from the sub-tank 6 to the filter chamber 8, and the fuel in the filter chamber 8 is the fuel that has passed through the filter 9 from within the main tank 2.

Most of the fuel sucked into the electric fuel bomb 20 is pumped to the engine, and a part of it is fed to the vapor discharge hole 26 provided in the first bomb 21 and a flow path 21a connecting the first bomb 21 and the second bomb 22. is discharged into the sub-tank 6 from a relief valve 27 provided in the sub-tank 6. Here, the difference between the fuel pumped to the engine by the electric fuel pump 20 and the fuel consumed by the engine is returned from the engine to the sub-tank 6 through the return pipe 12. This return fuel is fuel from which some of the low boiling point portion has been removed at high temperature.

Therefore, as the operation continues, the fuel pumped from the filter chamber 8 and the high-temperature fuel returned from the engine will gradually be stored in the sub-tank 6. When the fuel in the sub-tank 6 is about to exceed a predetermined level, the first float type rM closing valve 30 is opened and fuel is supplied from the sub-tank 6 to the filter chamber 8.

Here, as is clear from FIG. 2, the fuel supplied from the sub-tank 6 to the filter chamber 8 is fuel that does not pass through the filter 9. In other words, fuel that does not pass through the filter 9 and flows from the sub-tank 6 to the filter chamber 8 has more resistance when the electric fuel pump 20 draws it in than fuel that passes from the main tank 2 to the filter chamber 8 after passing through the filter 9. The electric fuel pump 20 is small and therefore preferentially sucks the fuel supplied from the sub-tank 6.

Due to the above structure, when the amount of fuel sucked into the electric fuel bomb 20 is greater than the amount of fuel supplied from the sub-tank 6 to the filter chamber 8, the insufficient amount of fuel is replenished from within the main tank 2. Further, as described above, since the electric fuel pump 20 preferentially sucks the fuel supplied from the sub-tank 6, the a-temperature fuel returned from the engine to the sub-tank 6 does not flow into the main tank 2. Therefore, the low-temperature fuel in the main tank 2 is not directly warmed by the high-temperature fuel returned from the engine, and the generation of vapor in the main tank 2 is suppressed.

Furthermore, after the engine is stopped, the fuel inside the pump is loosened by the heat of the electric fuel bomb 20 and becomes vapor, and this vapor flows out from the fuel suction port 23 and accumulates in the upper part of the filter chamber 8, and is filtered out. Situations also occur in which the liquid level in chamber 8 drops.

In this embodiment, the second float type on-off valve 40 is operated before the fuel suction port 23 is exposed from the fuel.
The fuel in the sub-tank 6 flows into the filter chamber 8, and conversely, the vapor accumulated in the upper part of the filter chamber 8 escapes to the sub-tank 6 side. Therefore, emptying of the electric charge bomb 20 is prevented, and the high temperature restart characteristics of the engine are restored.

Furthermore, even when the fuel in the main tank 2 is low and the fuel in the main tank 2 is tilted in one direction due to acceleration of the vehicle or inclination of the tank, the fuel suction port 23 in the filter chamber 8 is removed from the fuel. Before the electric fuel pump 20 is exposed, the second float type on-off valve 40 is opened to prevent the electric fuel pump 20 from emptying.

FIG. 3 shows a second embodiment of the present invention. 6 Components similar to those in the first embodiment are given the same numbers and their explanations are omitted.

In this embodiment, the float part of the second float type on-off valve 40 used in the first embodiment is modified, and the float 14
2 is provided below the filter chamber 8 in the main tank 2.

Fluctuations in fuel level due to acceleration of the vehicle, tilting of the tank, etc. are significantly delayed in the filter chamber 8 than in the main tank 2. Therefore, in order to respond quickly, main tank 2
It is more advantageous to catch the drop in fuel level within.

Therefore, in this embodiment, only the float 142 is provided in the main tank 2, and when the fuel level in the main tank 2 is about to drop below the level at the fuel suction port 23 of the electric fuel bomb 20, the float 142 is installed in the main tank 2. Float type on-off valve 1
It is adjusted to operate at 40tfi. This prevents the electric fuel pump 20 from emptying in a responsive manner.

FIG. 4 shows a third embodiment of the invention. Structures or members similar to those in the first embodiment are given the same numbers and explanations are omitted.

This embodiment shows an installation example in which the sub-tank 6 cannot be placed in the center of the main tank 2 but is placed at the end.
Only the filter 9 portion of the filter chamber 8 in the first embodiment is provided approximately in the center of the main tank 2.

For this reason, the structure of the second float type on-off valve 240 has been modified in accordance with the shape of the filter chamber 8.

Since it is functionally similar to the first embodiment, the explanation will be omitted.

Due to the above structure, the attachment position of the sub-tank 6 within the main tank 2 is not restricted.

[Effects of the Invention] According to the present invention, the high-temperature fuel from which low-boiling point components have been removed and returned from the engine is preferentially guided to the suction port of the fuel bomb and pressure-fed to the engine again. does not flow into the main tank, and the generation of vapor in the main tank is suppressed. Therefore, the size and weight of the barber processing device can be reduced.

Further, even if the fuel level in the filter chamber falls below a specified level, the second communication means operates to prevent the fuel bomb from emptying.

Therefore, a constant amount of fuel can be supplied to the engine regardless of the driving condition of the vehicle, and the high temperature restart characteristics of the engine can also be improved.

[Brief explanation of drawings]

FIG. 1 is an overall view of the installation of a vehicle fuel supply nail according to the present invention, FIG. 2 is a sectional view showing a first embodiment of the vehicle fuel supply device according to the present invention, and FIG. 3 is a vehicle fuel supply nail according to the present invention. FIG. 4 is a cross-sectional view showing a third embodiment of the vehicle fuel supply system according to the present invention. 27...Relief valve 30...First float type on-off valve 40...Second float type on-off valve 140...Second float type on-off valve 240...Second float type on-off valve

Claims (1)

[Scope of Claims] A main tank that is mounted on an object that is subjected to acceleration such as a vehicle and stores fuel, a sub-tank provided within the main tank, and a filter provided below the sub-tank. a fuel pump that supplies fuel from the filter chamber to the engine; a return passage that returns unconsumed fuel supplied to the engine to the sub-tank; and a return passage between the sub-tank and the filter chamber. a first communication means provided between the sub-tank and the first communication means for maintaining the fuel liquid level in the sub-tank at a predetermined value and supplying the fuel in the sub-tank to the filter chamber when the fuel liquid level exceeds the predetermined value; The second communication means is provided between the sub-tank and the filter chamber, and allows communication between the sub-tank and the filter chamber when the level of fuel in the filter chamber becomes below a specified level. fuel supply device.