JP5133093B2 - Vertical fuel tank - Google Patents

Description

  The present invention relates to a vertical fuel tank in which a fuel chamber is divided into two by projecting the central portion of the bottom surface upward, and can be suitably used particularly as a fuel tank for a vehicle.

  In general, in a front engine / rear drive type FR vehicle and a four-wheel drive (4WD) vehicle, a propeller shaft that transmits the driving force of the engine to the rear differential gearbox extends to the lower part of the vehicle body. And in order to balance a drive system, a propeller shaft is usually arrange | positioned at a vehicle body center. Therefore, the fuel tank arranged under the rear seat is formed in a so-called saddle shape in which the center of the bottom of the tank protrudes upward and the fuel chamber is divided into left and right so as not to interfere with the propeller shaft. The In the vertical fuel tank having such a shape, a fuel pump that supplies fuel to the engine is provided in either the left or right fuel chamber (hereinafter, the fuel chamber on the side where the fuel pump is provided is referred to as a main chamber), It is necessary to transfer the fuel in the other fuel chamber (hereinafter referred to as sub chamber) to the main chamber.

  In addition, when the fuel tank is installed below the rear seat, etc., the fuel tank is often flattened so that the seat does not become too high, so that the fuel in the fuel tank can be used to the end as much as possible. In addition, a fuel pump is disposed in the reserve container, and the remaining fuel is returned to the reserve container by returning the surplus fuel from the pressure regulator that discharges surplus fuel discharged from the fuel pump in order to keep the fuel pressure supplied to the engine constant. There is known a technique for keeping the liquid level in the reserve container higher than the surrounding liquid level even when the amount of fuel is reduced.

The main chamber is provided with a pump unit comprising a fuel pump, a pressure regulator, and a jet pump for sucking fuel from the sub chamber with a reduced negative pressure using surplus fuel from the pressure regulator. A vertical fuel tank is used (see Patent Document 1). According to this vertical fuel tank, it is not necessary to provide a separate electric pump for transferring fuel from the sub chamber to the main chamber, and the fuel pump structure is simplified.
JP 2004-324611 A

  However, in the vertical fuel tank described in Patent Document 1, since the fuel is always transferred from the sub chamber side to the main chamber side while the engine is driven, the liquid levels in the main chamber and the sub chamber are different. Therefore, in order to grasp the remaining amount of fuel, fuel meter units must be provided in both the main chamber and the sub chamber.

  This not only increases the number of parts and the number of assembly steps because a single fuel tank requires a plurality of unit mounting holes, but also increases the amount of fuel permeated from the seal location in order to seal the plurality of unit mounting holes. In addition, as a measure for suppressing the fuel permeation amount of the entire fuel system to a predetermined value, it is necessary to use an expensive material having a small fuel permeability for other fuel-related parts.

  The present invention has been made in view of such a background, and provides a vertical fuel tank that includes a plurality of fuel storage chambers and includes a fuel supply device with a simple configuration capable of grasping the remaining fuel. Objective.

  In order to solve the above-described problems, the present invention provides a vertical fuel tank that includes first and second fuel chambers defined by a central portion of a lower wall projecting upward, and the first fuel chamber. An installed reserve container, a fuel pump installed in the reserve container and pumping fuel stored in the reserve container to the prime mover side through a supply pipe, and a pressure regulator provided in a pipe line of the supply pipe One end of which is inserted into the reserve container, returns excess fuel discharged from the pressure regulator to the reserve container, and a return pipe having a negative pressure generating portion formed in the pipe line, A siphon pipe that communicates the bottom of one fuel chamber and the bottom of the second fuel chamber, a suction pipe that connects the siphon pipe and the negative pressure generator, and A one-way valve that is provided in the passage and restricts the flow of fuel from the negative pressure generation unit side to the siphon piping side, and a fuel amount detection unit that detects a fuel amount in the first fuel chamber. To do.

  In the fuel device having the above-described configuration, the reserve container, the fuel pump, the pressure regulator, the return pipe, the siphon pipe, the suction pipe, the one-way valve, and the fuel amount detection means. May constitute a fuel supply module attached to one attachment hole. The one-way valve includes an orifice that allows gas to flow from the siphon piping side to the negative pressure generating portion side, and is configured to regulate the flow of fuel flowing from the siphon piping side to the negative pressure generating portion side. Good.

  According to the present invention, even when gas is present in the siphon piping, the gas in the siphon piping is sucked by the negative pressure generating portion through the suction piping, and the siphon piping is filled with fuel. It becomes possible to demonstrate the function. Therefore, the liquid level height of the fuel stored in the first and second fuel chambers is kept the same, and an accurate fuel amount can be grasped even if only one fuel detection means is used. Further, since the reflux pipe is inserted into the reserve container, it is possible to prevent the fuel from being bubbled and the bubbles from being mixed into the fuel when the excess fuel is returned to the reserve container. Further, since the one-way valve is provided in the pipe line of the suction pipe, the fuel liquid level in the first and second fuel chambers is the same as the liquid level in the reserve container when the fuel pump is stopped. Even if it is lower than this, the fuel in the reserve container is prevented from being sucked through the suction pipe and the siphon pipe.

  In addition, the above-described components can be assembled together before being attached to the fuel tank, and by adopting the configuration of one integrally formed fuel supply module, the components can be easily attached to the fuel tank. Since it becomes possible to complete the installation hole of the fuel tank formed to attach these components, the sealing process of the attachment portion is only required at one place, and the safety against the leakage of evaporating gas is enhanced.

  Further, the one-way valve has an orifice, and gas is circulated from the siphon pipe side to the negative pressure generating side, while the gas in the siphon pipe is once removed by restricting the flow of fuel flowing in the same direction. After that, the external force (suction force) by the suction pipe is eliminated, and a large amount of fuel is sucked from one of the first and second fuel chambers due to a difference in flow resistance, etc., resulting in a difference in liquid level height between both fuel chambers. This can be prevented.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<< Configuration of Embodiment >>
FIG. 1 is a sectional view of a vertical fuel tank 1 according to this embodiment. As shown in the figure, a vertical fuel tank 1 mounted on a vehicle has a center portion 2c of a tank bottom wall 2 protruding upward in an arc shape, and the bottom portion is defined by one side portion 2a of the tank bottom wall 2. And a sub chamber 5 whose bottom is defined by the other side 2b of the tank bottom wall 2. In the present specification, a fuel chamber on the side where a fuel pump, which will be described later, is installed is called a main chamber, and the other fuel chamber is called a sub chamber. A mounting hole 3 a for the fuel supply module 10 is formed in the top wall 3 of the vertical fuel tank 1. Further, the ceiling wall 3 is formed with a filler pipe 6 for fuel injection and a mounting hole for a float valve connected to a canister (not shown).

  The fuel supply module 10 is inserted through the mounting hole 3a of the top wall 3, and a reserve container 11 installed at the bottom of the main chamber 4 and a mounting flange 10a that closes the mounting hole 3a are integrally formed to form a casing. ing. The reserve container 11 always stores fuel up to its upper end 11a even when the fuel in the vertical fuel tank 1 is small, and the vehicle body is inclined when the vehicle suddenly starts or stops or turns suddenly, or on a slope. Even when it is in a state, the fuel liquid level can be maintained at a predetermined height. When mounting the fuel supply module 10 to the top wall 3 of the vertical fuel tank 1, the mounting flange 10 a allows the evaporative gas in the tank to leak by interposing the seal material 7 between the top wall 3 and the mounting flange 10 a. So that there is no.

  A sender unit 22 that detects the liquid level of the fuel stored in the main chamber 4 is attached to the side of the reserve container 11. The sender unit 22 includes a float 23, and detects the fuel liquid level by detecting the position of the float 23 that has moved up and down in accordance with the change in the liquid level of the fuel.

  An impeller-driven fuel pump 12 that rotates the impeller with a motor and discharges fuel is installed at the bottom of the reserve container 11. A filter 13 is attached to the suction side of the fuel pump 12, and a supply pipe 14 connected to the prime mover side is connected to the discharge side. A fuel filter 15 and a pressure regulator 16 that keeps the fuel pressure from the fuel pump 12 applied to the injector constant are provided in the pipeline of the supply pipe 14 in the fuel supply module 10. The pressure regulator 16 includes a spring chamber that is opened in the tank, and when the fuel pressure becomes higher than the tank internal pressure by a predetermined pressure or more, the diaphragm is pulled to discharge excess fuel.

  A reflux pipe 17 is connected to the pressure regulator 16. The lower end of the reflux pipe 17 is inserted into the reserve container 11, and surplus fuel discharged from the pressure regulator 16 is returned to the reserve container 11. In addition, a jet pump 18 that generates a negative pressure by using the pressure of excess fuel that is returned to the reserve container 11 is provided in the conduit of the reflux pipe 17. The jet pump 18 has a well-known configuration using the pressure difference of the Venturi pipe, and generates a negative pressure between a nozzle whose pipe diameter is rapidly reduced and a pipe line where the pipe diameter gradually increases thereafter. . One end of a suction pipe 21 is connected to the negative pressure portion of the jet pump 18.

  In the vertical fuel tank 1, one end of the vertical fuel tank 1 is opened near the upper surface of the bottom portion of the main chamber 4, that is, one side portion 2a of the tank bottom wall 2 so as to straddle the central portion 2c of the tank bottom wall 2. A siphon pipe 19 having an end opened near the bottom of the sub chamber 5, that is, near the upper surface of the other side 2 b of the tank bottom wall 2 is installed. The siphon pipe 19 has an arcuate upper portion along the central portion 2c of the tank bottom wall 2, and filters 20a and 20b are attached to both ends thereof.

  The other end of the suction pipe 21 described above is connected to the top portion 19 a of the siphon pipe 19. Further, a one-way valve 30 for restricting the flow of fuel from the jet pump 18 side to the siphon pipe 19 side is provided in the pipe line of the suction pipe 21.

  The one-way valve 30 will be described with reference to FIG. FIG. 2 shows a longitudinal section of the one-way valve 30, and (A) in the figure shows a state in which no pressure acts on the suction pipe 21 in any direction. As shown in the figure, the one-way valve 30 includes a cylindrical casing 31 and a siphon pipe-side joint pipe that extends along the axis toward one end of the casing 31 and is connected to a suction pipe 21 on the siphon pipe 19 side. 32, the other end side of the casing 31 extends along the axis, and is slidably accommodated inside the casing 31 and the jet pump side joint pipe 33 connected to the suction pipe 21 on the jet pump 18 side. And a coil spring 36 that urges the valve body 34 toward the siphon pipe side joint pipe 32.

  The siphon pipe side joint pipe 32 and the jet pump side joint pipe 33 have substantially the same diameter. The valve body 34 is in elastic contact with the end portion 32a of the siphon pipe side joint pipe 32 and closes the opening. The valve body 34 is formed with a plurality of orifices 35 having minute diameters at positions farther from the axis than the outer diameters of the joint pipes 32 and 33.

<< Effects of Embodiment >>
Next, with reference to FIG. 1 and FIG. 2, the effect of the vertical fuel tank 1 which concerns on this embodiment is demonstrated. 2B shows a state in which the evaporative gas flows from the jet pump 18 side to the siphon piping 19 side, and FIG. 2C shows the state in which the fuel on the siphon piping 19 side is sucked to the jet pump 18 side . It shows the state.

  As shown in FIG. 1, when the fuel pump 12 is activated, the fuel stored in the reserve container 11 is discharged to the supply pipe 14. When the fuel pressure does not reach the predetermined value described above, all of the fuel flowing through the supply pipe 14 flows to the prime mover side via the fuel filter 15. When the fuel pressure reaches a predetermined value, the diaphragm of the pressure regulator 16 is pulled, and surplus fuel is discharged to the reflux pipe 17. The fuel flowing through the reflux pipe 17 generates a negative pressure when passing through the jet pump 18 and makes the suction pipe 21 have a negative pressure.

  At this time, if a gas such as air or evaporative gas exists in the suction pipe 21 or the siphon pipe 19, the valve body 34 slides toward the jet pump side joint pipe 33 as shown in FIG. The opening of the pipe side joint pipe 32 is opened. The gas flowing in from the siphon piping side joint pipe 32 flows through the orifice 35 and flows into the jet pump side joint pipe 33.

  On the other hand, when there is no gas in the suction pipe 21 (when the fuel is full) or when all the gas is sucked and the fuel is sucked from the siphon pipe 19, as shown in FIG. The valve body 34 slides toward the jet pump side joint pipe 33, and fuel flows into the one-way valve 30 from the opening of the siphon pipe side joint pipe 32. The fuel that has flowed into the one-way valve 30 flows into the orifice 35. However, since the fuel has a larger flow resistance than the gas, the valve body 34 is overcome by the urging force of the coil spring 36 and the jet pump side joint pipe 33 is overcome. The opening is closed by contacting the end 33a. Accordingly, the flow of fuel flowing from the siphon pipe side joint pipe 32 to the jet pump side joint pipe 33 is restricted.

  Thus, when the gas in the siphon pipe 19 is sucked into the jet pump 18, the siphon pipe 19 filled with fuel exhibits the siphon function, and the fuel level in the main chamber 4 and the fuel in the sub chamber 5. The liquid level is always kept the same. Therefore, it becomes possible to grasp the fuel amount stored in the vertical fuel tank 1 from the fuel amount detected by the sender unit 22.

  When the fuel pump 12 stops together with the engine stop, the jet pump 18 also stops generating negative pressure, and the one-way valve 30 returns to the state shown in FIG. As a result, the fuel in the reserve container 11 does not flow to the siphon pipe 19 side, and the situation where the engine cannot be restarted is prevented.

  Further, the one-way valve 30 regulates the flow of the fuel flowing from the siphon pipe side joint pipe 32 to the jet pump side joint pipe 33, so that an external force does not act on the fuel in the siphon pipe 19 and a difference in flow resistance, etc. This prevents a large amount of fuel from being sucked from the main chamber 4 or the sub chamber 5 to cause a difference in liquid level between the fuel chambers 4 and 5.

  Further, the reserve container 11, the fuel pump 12, the pressure regulator 16, the reflux pipe 17, the siphon pipe 19, the suction pipe 21, the one-way valve 30, and the sender unit 22 are assembled in advance and supplied with fuel. By configuring the module 10, the module 10 can be easily attached to the vertical fuel tank 1. Furthermore, since only one mounting hole 3a is required for mounting the fuel supply module 10, safety against leakage of evaporative gas from the mounting portion is enhanced.

  This is the end of the description of specific embodiments, but the present invention is not limited to these embodiments. For example, in the above-described embodiment, the one-way valve circulates the gas while restricting the circulation of the fuel, but it may be of a type that also circulates the fuel. Further, the fuel amount detecting means is not limited to the float type sender unit, and any method may be used as long as it can detect the fuel amount stored in the vertical fuel tank. Furthermore, in addition to these changes, changes can be made as appropriate without departing from the spirit of the present invention.

Sectional view of vertical fuel tank according to an embodiment Longitudinal section of one-way valve

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vertical fuel tank 2 Bottom wall 2c Center part of bottom wall 3 Top wall 4 Main room (1st fuel chamber)
5 Sub chamber (second fuel chamber)
DESCRIPTION OF SYMBOLS 10 Fuel supply module 11 Reserve container 14 Supply piping 16 Pressure regulator 17 Reflux piping 18 Jet pump (negative pressure generating part)
19 Siphon piping 19a Siphon piping top 21 Suction piping 22 Sender unit 30 One-way valve 31 Casing 34 Valve body 35 Orifice

Claims (3)

First and second fuel chambers defined by a central portion of the lower wall projecting upward;
A reserve container installed in the first fuel chamber;
A fuel pump installed in the reserve container and pumping fuel stored in the reserve container to the prime mover side via a supply pipe;
A pressure regulator provided in the pipeline of the supply pipe;
One end thereof is inserted into the reserve container, the excess fuel discharged from the pressure regulator is recirculated to the reserve container, and a reflux pipe in which a negative pressure generating portion is formed in the pipe line;
Siphon piping for communicating the bottom of the first fuel chamber and the bottom of the second fuel chamber;
A suction pipe connecting the siphon pipe and the negative pressure generator;
When the negative pressure generating unit makes the suction pipe negative pressure, the gas is allowed to flow from the siphon piping side to the negative pressure generating side and the fuel is allowed to flow. A one-way valve that regulates the flow of gas and fuel from the negative pressure generation unit side to the siphon piping side when the negative pressure generation unit does not generate negative pressure,
A vertical fuel tank comprising fuel amount detection means for detecting a fuel amount in the first fuel chamber. The one-way valve has a casing, a valve body slidably accommodated inside the casing, and a coil spring that biases the valve body toward the siphon piping.
Said valve body, according to claim 1, wherein the negative pressure generating portion is an orifice for circulating gas into the negative pressure generating portion from the siphon pipe side when the suction pipe negative pressure is formed The fuel tank as described in. The reserve container, the fuel pump, the pressure regulator, the reflux pipe, the siphon pipe, the suction pipe, the one-way valve, and the fuel amount detection means are attached to one mounting hole. the fuel tank according to claim 1 or claim 2, characterized in that a fuel supply module that is.

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