WO2020189558A1

WO2020189558A1 - Liquid tank

Info

Publication number: WO2020189558A1
Application number: PCT/JP2020/011121
Authority: WO
Inventors: 俊之関
Original assignee: いすゞ自動車株式会社
Priority date: 2019-03-20
Filing date: 2020-03-13
Publication date: 2020-09-24
Also published as: JP2020152252A

Abstract

A liquid tank 1 that comprises a tank body 2, a filler pipe 3 that is connected to the tank body 2 and is for injecting liquid into the tank body 2, a breather pipe 4 that is connected to the tank body 2 and the filler pipe 3 and is for discharging gas from the tank body 2 when liquid is injected, a communication pipe 21 that is connected to the tank body 2 and communicates with the inside of the tank body 2, and an elastically expandable/contractible rubber bag-like body 22 that is arranged outside the tank body 2 and communicates with the inside of the tank body 2 via the communication pipe 21.

Description

Liquid tank

The present disclosure relates to a liquid tank, and more particularly to a liquid tank suitable for storing a liquid such as a fuel for an internal combustion engine in a vehicle.

For example, in a vehicle, the fuel of an internal combustion engine, which is a liquid, is stored in a fuel tank as a liquid tank. The fuel tank includes a tank body which is a container for substantially storing fuel, a filler pipe for injecting fuel into the tank body, and a breather pipe for discharging gas in the tank body when injecting fuel. ..

Japanese Patent Application Laid-Open No. 5-286371

The outlet of the breather pipe is connected to the inlet of the filler pipe, and the gas through the breather pipe is released to the atmosphere from the outlet of the breather pipe via the inlet of the filler pipe.

Here, there is no particular problem when the flow rate of the fuel supplied to the filler pipe at the time of refueling is small. However, if the flow rate is high, the pressure of the gas in the tank body rises, and the fuel in the tank body is pushed out into the breather pipe. Then, there is a problem that the fuel flows back in the filler pipe after being discharged from the outlet portion of the breather pipe and is ejected to the outside from the inlet portion of the filler pipe.

In order to solve this problem, it is conceivable to connect a rubber bellows (bellows) to the tank body via a pipe, for example, as described in Patent Document 1. By doing so, even if the gas pressure in the tank body rises, the bellows expands and suppresses the rise in the gas pressure, so that the fuel ejection due to the rise in the gas pressure can be suppressed.

However, since the bellows has a structure that bends and expands and contracts only at a predetermined bending point, there is a risk that cracks and the like may occur at the bending point due to repeated expansion and contraction and bending. Therefore, in terms of durability, bellows is not always the best solution.

The purpose of this disclosure is to provide a liquid tank with high durability.

The liquid tank of the present disclosure is
With the tank body
A filler pipe connected to the tank body and for injecting a liquid into the tank body,
A breather pipe connected to the tank body and the filler pipe for discharging gas in the tank body when a liquid is injected.
A communication pipe connected to the tank body and communicated with the inside of the tank body,
An elastically expandable and contractible rubber bag-like body arranged outside the tank body and communicating with the inside of the tank body via the communication pipe.
To be equipped.

Preferably, the bag-shaped body has a spherical portion and a mouth portion that protrudes outward in the radial direction from the spherical portion.

Preferably, the bag-shaped body has a cylindrical shape with one end closed and the other end open.

Preferably, the opening on the inner side of the tank body of the communication pipe is located higher than the opening on the tank body side of the breather pipe.

According to the present disclosure, it is possible to provide a liquid tank having high durability.

FIG. 1 is a schematic cross-sectional view showing a part of a fuel tank according to an embodiment. FIG. 2 is an enlarged cross-sectional view showing the structures of the filler pipe and the breather pipe. FIG. 3 is an enlarged cross-sectional view showing the structure of the communication pipe and the bag-shaped body. FIG. 4 is an enlarged cross-sectional view showing a modified example. FIG. 5 is a schematic cross-sectional view showing another modified example.

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be noted that the present disclosure is not limited to the following embodiments.

FIG. 1 is a schematic view showing a part of the liquid tank according to the embodiment. The liquid tank of the present embodiment is applied as a fuel tank 1 for storing fuel of an internal combustion engine (engine) in a vehicle, and the liquid to be stored is fuel. The vehicle is a large vehicle such as a truck, the internal combustion engine is a diesel engine, and the fuel is light oil. However, the type, application, etc. of the vehicle, internal combustion engine, and fuel are not particularly limited. For example, the vehicle may be a small vehicle such as a passenger car, the engine may be a gasoline engine, and the fuel may be gasoline. You may.

The engine may be mounted on a moving body other than a vehicle, for example, a ship, a construction machine, or an industrial machine. Further, the engine does not have to be mounted on a moving body, and may be a stationary engine.

The fuel tank 1 is connected to a tank body 2 which is a container for substantially storing fuel (not shown), a filler pipe 3 which is connected to the tank body 2 and for injecting fuel into the tank body 2, and a tank body 2. And a breather pipe 4 connected to the filler pipe 3 and for discharging the gas in the tank body 2 at the time of fuel injection.

The tank body 2 of this embodiment is made of resin. However, the material is arbitrary and may be made of metal.

The filler pipe 3 has an outlet portion 5 as one end portion inserted and fixed to the tank body 2 from the side, and extends upward (obliquely upward in the illustrated example) from the outlet portion 5. Further, the filler pipe 3 has an inlet portion 6 as the other end portion located above the outlet portion 5. The filler pipe 3 is supplied with fuel from the refueling nozzle Z inserted into the inlet portion 6 from the outside, guides the supplied fuel and discharges the supplied fuel into the tank body 2 from the outlet portion 5, and discharges the fuel into the tank body 2. Inject into 2. The filler pipe 3 is capable of efficiently injecting fuel by utilizing the head between the inlet portion 6 and the outlet portion 5.

Although optional, a tapered nozzle insertion pipe 7 is provided inside the inlet portion 6 of the filler pipe 3 to insert and position the refueling nozzle Z and prevent fuel from blowing back as much as possible. A filler cap 8 is detachably attached to the inlet portion 6 of the filler pipe 3.

The breather pipe 4 has an inlet portion 9 as one end portion inserted and fixed to the tank body 2 from above, and extends upward (obliquely upward in the illustrated example) from the inlet portion 9. Further, the breather pipe 4 has an outlet portion 10 as the other end portion located above the inlet portion 9. The outlet portion 10 is connected to the inlet portion 6 of the filler pipe 3 on the outer peripheral side of the nozzle insertion pipe 7. The breather pipe 4 has a smaller diameter than the filler pipe 3 and has a circular cross section. For example, the inner diameter of the filler pipe 3 is about 30 to 40 mm, and the inner diameter of the breather pipe 4 is about 12 mm.

The breather pipe 4 is sometimes referred to as a breather tube, a vent pipe, a vent tube, or the like.

FIG. 2 shows in detail the structures of the filler pipe 3 and the breather pipe 4. As shown in the figure, the breather pipe 4 is divided into three parts in the longitudinal direction, and the inlet portion 9 formed of the L-shaped pipe, the outlet portion 10 formed of the same L-shaped pipe, and these inlet portions 6 It also has an intermediate portion 11 that connects the outlet portion 10.

The intermediate portion 11 is formed by a flexible hose. The inlet end portion of the intermediate portion 11 is closely fitted to the outside of the inlet portion 9, and is tightened and fixed from the outer peripheral side by the fastening band 12. Similarly, the outlet end portion of the intermediate portion 11 is closely fitted to the outside of the outlet portion 10, and is tightened and fixed from the outer peripheral side by the fastening band 12. Other methods are also possible for connecting the intermediate portion 11. For example, when connecting the intermediate portion 11 to the inlet portion 9, a connection method using a quick connector or a connection method by press fitting can also be adopted.

The entrance portion 9 has a vertical portion 13 located on the inlet side thereof and extending in the vertical direction, and a horizontal portion 14 located on the exit side thereof and curved from the upper end of the vertical portion 13 and extending in the horizontal direction or the horizontal direction. The lateral portion 14 is located outside the tank body 2, and the inlet end portion of the intermediate portion 11 is connected.

An insertion hole 15 is provided in the upper surface portion 2A of the tank body 2, and the vertical portion 13 of the inlet portion 9 is inserted into the insertion hole 15 from above. A mounting flange 16 is fixed to the outer peripheral portion of the vertical portion 13, and the mounting flange 16 is fixed to the upper surface portion 2A of the tank body 2 so that the inlet portion 9 is fixed to the tank body 2.

In the present embodiment, the inlet portion 9 and the mounting flange 16 are made of the same resin as the tank body 2. The mounting flange 16 has a shape like an inverted ring plate, and is integrally molded on the outer peripheral portion of the vertical portion 13. Further, the lower end surface 17 of the mounting flange 16 is integrally fixed to the upper surface portion 2A of the tank body 2 by heat welding or the like. As a result, the inlet portion 9 is fixed to the tank body 2 while preventing fuel leakage and gas leakage from the tank body 2.

If the tank body 2, the inlet 9, and the mounting flange 16 are made of metal, the mounting flange 16 is welded to the inlet 9 and the tank body 2.

When the inlet portion 9 is fixed in this way, the lower half portion of the vertical portion 13 is arranged downward in the tank body 2. That is, the inlet portion 9 is arranged in the tank body 2 with the circular inlet opening 19 (see FIG. 1) located at the lower end 18 thereof facing downward. As shown in FIG. 1, the height position H2 of the lower end 18 to the inlet opening 19 is higher than the height position H1 of the upper end of the outlet opening 20 of the filler pipe 3. The lower end 18 is perpendicular to the axial direction of the vertical portion 13.

In addition, in the present embodiment, a bag-shaped body 22 communicated via a communication pipe 21 is provided inside the tank body 2. The bag-shaped body 22 is made of rubber and can elastically expand and contract.

FIG. 3 shows in detail the structures of the communication pipe 21 and the bag-shaped body 22. As shown in the figure, the communication pipe 21 is connected to the tank body 2 and communicates with the inside of the tank body 2. The communication pipe 21 is formed by a relatively short linear pipe in this embodiment. The communication pipe 21 is inserted into the pipe insertion hole 23 formed in the upper surface portion 2A of the tank body 2 in the vertical direction from above. Similarly to the above, the mounting flange 24 is fixed to the outer peripheral portion of the communication pipe 21, and the mounting flange 24 is fixed to the upper surface portion 2A of the tank body 2 to fix the communication pipe 21 to the tank body 2.

In the present embodiment, the communication pipe 21 and the mounting flange 24 are made of the same resin as the tank body 2. The mounting flange 24 has a shape like an inverted ring plate, and is integrally molded on the outer peripheral portion of the communication pipe 21. Further, the lower end surface 24A of the mounting flange 24 is integrally fixed to the upper surface portion 2A of the tank body 2 by heat welding or the like. As a result, the communication pipe 21 is fixed to the tank body 2 while preventing fuel leakage and gas leakage from the tank body 2.

If the tank body 2, the communication pipe 21, and the mounting flange 24 are made of metal, the mounting flange 24 is welded to the communication pipe 21 and the tank body 2.

When the communication pipe 21 is fixed in this way, the lower end of the communication pipe 21 is arranged downward in the tank body 2. That is, the communication pipe 21 is arranged in the tank main body 2 with the circular inlet opening 27 located at the inlet end or the lower end 26 thereof facing downward. As shown in FIG. 1, the height position H3 of the lower end 26 to the inlet opening 27 is higher than the height position H2 of the inlet opening 19 of the breather pipe 4. The lower end 26 is perpendicular to the axial direction of the communication pipe 21.

The method of fixing the communication pipe 21 is arbitrary, and it may be fixed by screwing or the like. The material of the communication pipe 21 is also arbitrary. Further, the height position H3 of the inlet opening 27 of the communication pipe 21 may be any height position as long as it is higher than the height position H2 of the inlet opening 19 of the breather pipe 4, for example, the upper surface portion 2A of the tank body 2. It may be at the same height position as.

The upper end of the communication pipe 21 is located outside the tank body 2 and above the upper surface 2A of the tank body 2. The upper end of the communication pipe 21 has an outlet end or an upper end 28, and a circular upward outlet opening 29 located at the upper end 28.

The bag-shaped body 22 is connected to the upper end of the communication pipe 21. Therefore, the bag-shaped body 22 is arranged outside the tank body 2.

The bag-shaped body 22 is integrally formed of a rubber material, and has a spherical portion 30 and a mouth portion 31 protruding outward in the radial direction from the spherical portion 30. That is, the bag-shaped body 22 of the present embodiment is configured like a balloon.

Although the spherical portion 30 of the present embodiment has an elliptical spherical shape, it may have a perfect spherical shape or a similar spherical shape.

The mouth portion 31 has a cylindrical shape, is located at the lower end portion of the spherical portion 30, and is directed downward. The mouth portion 31 is elastically closely fitted to the outside of the upper end portion of the communication pipe 21, and is tightened and fixed from the outer peripheral side by the fastening band 32. The outer diameter of the mouth portion 31 is smaller than the diameter of the spherical portion 30 (meaning the average diameter).

The rubber material forming the bag-shaped body 22 is an oil-resistant rubber having sufficient resistance to fuel, for example, nitrile rubber (NBR) or fluororubber. The wall thickness of the bag-shaped body 22 is set to a sufficient wall thickness so that cracks and the like do not occur over a predetermined durability period even if repeated expansion and contraction occur.

In this way, the bag-shaped body 22 is communicated with the upper space inside the tank body 2 via the communicating pipe 21.

By the way, assuming a comparative example in which the communication pipe 21 and the bag-shaped body 22 are not provided and the pipe insertion hole 23 is also closed, this comparative example has the following problems.

As shown in FIG. 1, for example, when refueling an empty fuel tank 1 to a full tank, the refueling nozzle Z of the refueling gun is inserted into the nozzle insertion pipe 7 at the inlet 6 of the filler pipe 3 to start refueling.

The liquid level in the tank body 2 gradually rises, and eventually the liquid level reaches the height position H1 at the upper end of the outlet opening 20 of the filler pipe 3. In that case, the outlet opening 20 of the filler pipe 3 is closed with fuel. After that, the liquid level rises in the tank body 2 and in the filler pipe 3. At this time, the gas (referred to as the gas in the tank) in the space above the liquid level (referred to as the space in the tank) in the tank body 2 is released to the atmosphere through the breather pipe 4. Here, the gas in the tank is a mixture of air and fuel vapor.

Specifically, the gas in the tank is pushed into the breather pipe 4 from the inlet 9 of the breather pipe 4 due to the rise in the liquid level. The gas in the tank pushed in rises in the breather pipe 4, and is discharged from the outlet portion 10 into the inlet portion 6 of the filler pipe 3. Then, the gas in the tank flows through the gap between the nozzle insertion pipe 7 and the refueling nozzle Z in the reverse flow direction opposite to the refueling direction, and is discharged from the inlet portion 6 of the filler pipe 3 to the atmosphere.

After that, as shown in FIG. 2, the liquid level reaches the height position H2 of the lower end 18 of the inlet portion 9 of the breather pipe 4. In that case, the inlet opening 19 of the breather pipe 4 is closed with fuel.

Here, it is assumed that the flow rate of the fuel supplied to the filler pipe 3 is sufficiently small (that is, the refueling speed is sufficiently slow). In this case, after the inlet opening 19 of the breather pipe 4 is closed with fuel, the rise of the liquid level in the tank body 2 stops. Instead, the fuel penetrates into the breather pipe 4 through the inlet opening 19 and the liquid level rises in the filler pipe 3 and in the breather pipe 4. As the liquid level in the breather pipe 4 rises, the gas in the tank above the liquid level is pushed upward and released to the atmosphere.

Then, when the liquid level reaches the height position H4 of the fuel detection sensor (for example, pressure sensor) S attached to the tip of the refueling nozzle Z, refueling is automatically stopped. Since this height position H4 is sufficiently lower than the outlet opening 25 of the breather pipe 4, fuel discharge from the outlet portion 10 of the breather pipe 4 into the filler pipe 3 is prevented.

However, if the flow rate of the fuel supplied to the filler pipe 3 is large (that is, the refueling speed is high), the following problems may occur. Immediately after the liquid level reaches the height position H2 and the inlet opening 19 of the breather pipe 4 is closed with fuel, the rise in the liquid level in the tank body 2 should stop, but the fuel flow rate is high. Therefore, the liquid level rises slightly, the gas in the tank in the tank body 2 is compressed, and the pressure of the gas in the tank rises sharply. As a result, the gas in the tank rapidly pushes the fuel in the tank body 2 into the breather pipe 4. Then, the extruded fuel soars in the breather pipe 4, and is ejected from the inlet portion 6 of the filler pipe 3 to the outside at substantially the same timing as, for example, when the refueling is automatically stopped.

That is, the fuel that has risen sharply in the breather pipe 4 is discharged from the outlet portion 10 into the inlet portion 6 of the filler pipe 3, and then in the nozzle insertion pipe 7 and the refueling nozzle Z, as in the above-mentioned gas discharge path. Through the gap, it flows in the reverse flow direction opposite to the refueling direction, and is ejected from the inlet portion 6 of the filler pipe 3 to the outside.

It should be noted that this fuel ejection occurs when (i) the breather pipe 4 has a smaller diameter than the filler pipe 3 and the fuel rising speed tends to increase, and (ii) the filler pipe 3 becomes long or has a complicated shape due to the vehicle layout. Another cause is that the fuel rising speed in the filler pipe 3 is difficult to increase.

Therefore, in the present embodiment, the bag-shaped body 22 is provided in order to suppress or prevent such fuel ejection. In this case, the following effects can be obtained. It is assumed that the flow rate of the fuel supplied to the filler pipe 3 is large.

Immediately after the liquid level reaches the height position H2 and the inlet opening 19 of the breather pipe 4 is closed with fuel, the liquid level in the tank body 2 rises slightly, the gas in the tank is compressed, and the inside of the tank is compressed. The gas pressure is about to skyrocket.

However, at this time, the gas inside the bag-shaped body 22 (particularly the spherical portion 30) communicating with the space inside the tank is also compressed at the same time and tries to increase the pressure, so that the bag-shaped body 22 is elastically expanded and the pressure is increased. The rise can be suppressed. As a result, it is possible to suppress or prevent the fuel from being pushed out into the breather pipe 4 and being ejected from the inlet portion 6 of the filler pipe 3 to the outside.

In particular, since the height position H3 of the inlet opening 27 of the communication pipe 21 is higher than the height position H2 of the inlet opening 19 of the breather pipe 4, the inside of the tank immediately after the inlet opening 19 of the breather pipe 4 is closed with fuel. The gas can be introduced into the communication pipe 21 from the inlet opening 27 without any trouble, and the bag-shaped body 22 can be surely expanded.

As a matter of course, the height position H3 of the inlet opening 27 of the communication pipe 21 is such that the liquid level in the tank body 2 rises slightly immediately after the inlet opening 19 of the breather pipe 4 is closed with fuel. , The inlet opening 27 of the communication pipe 21 is set at a sufficient height position so as not to be blocked by fuel.

The bag-shaped body 22 of the present embodiment is formed in a bag shape as its name suggests. Therefore, when the expansion and contraction are performed, the expansion and contraction is performed on the entire body except the fixed mouth portion 31, particularly the spherical portion 30. Therefore, unlike the bellows described in Patent Document 1, the bending is not performed only at a specific bending point, and problems such as cracks at the bending point due to repeated bending can be avoided. Therefore, it is possible to provide the fuel tank 1 having high durability.

Further, since the bag-shaped body 22 of the present embodiment has a balloon-like structure integrally molded with a rubber material, it can be easily manufactured and inexpensively manufactured. There is also the possibility that general-purpose products can be used.

By the way, when the filler cap 8 is closed after refueling and the fuel tank 1 is normally used, the pressure of the gas in the tank becomes negative due to fuel consumption by the engine, or the pressure of the gas in the tank becomes large due to the rise in tank temperature or the like. It rises above the pressure. In response to such a decrease or increase in pressure, that is, a fluctuation in pressure, for example, the breather valve provided in the filler cap 8 can be opened to introduce outside air or discharge gas in the tank to suppress the pressure fluctuation. is there.

However, when the gas in the tank becomes negative pressure to the extent that the breather valve does not open, the bellows described in Patent Document 1 may contract excessively and give an excessive load to the bending point of the bellows or the like. is there.

On the other hand, in the present embodiment, only the entire bag-shaped body 22 (particularly the spherical portion 30) is withered, and an excessive load is not applied to the bag-shaped body 22. Therefore, the durability can be improved by this as well.

Next, a modified example of this embodiment will be described. The same parts as those in the basic embodiment are designated by the same reference numerals in the drawings, and the description thereof will be omitted. Hereinafter, the differences from the basic embodiment will be mainly described.

Also in the modified example shown in FIG. 4, the bag-shaped body 22 is integrally formed of a rubber material. However, the shape of the bag-shaped body 22 is different from that of the basic embodiment, and is formed in a cylindrical shape in which one end, that is, the upper end is closed and the other end, that is, the lower end is open. In the case of this embodiment, the upper end, that is, the closed end 33 has a spherical shape. However, other shapes, such as flat shapes, may be used. Like the mouth portion 31, the lower end portion 34 of the bag-shaped body 22 is elastically closely fitted to the outside of the upper end portion of the communication pipe 21, and is tightened and fixed from the outer peripheral side by the fastening band 32.

The bag-shaped body 22 having such a shape can also exert the same action and effect as described above.

In addition to this, the shape of the bag-shaped body 22 can be changed arbitrarily.

Although the embodiments of the present disclosure have been described in detail above, various other embodiments and modifications of the present disclosure can be considered.

(1) For example, the present disclosure is applicable to a liquid tank other than a fuel tank, which stores a liquid other than fuel. For example, some vehicles equipped with a diesel engine are equipped with an SCR (Selective Catalyst Reduction) device for reducing and purifying NOx in the exhaust. Liquid urea water is used as a reducing agent in the SCR device, and a urea water tank for storing the urea water is mounted on the vehicle. When the urea water is injected into the urea water tank, the same urea water as described above may be ejected. In this case, the present disclosure can be applied to the urea water tank to suppress the ejection of urea water.

(2) The structure of the communication pipe can be changed. For example, as shown in FIG. 5, the communication pipe 21 may be made longer or bent so that the bag-shaped body 22 may be arranged at a position further away from the tank body 2. The communication pipe may have a divided structure such as the breather pipe 4.

(3) The orientation of the bag-shaped body is not limited to the downward orientation as in the above embodiment, and can be set to any orientation (for example, sideways orientation, upward orientation, etc.).

The embodiments of the present disclosure are not limited to the above-described embodiments, and all modifications, applications, and equivalents included in the idea of the present disclosure defined by the scope of claims are included in the present disclosure. Therefore, the present disclosure should not be construed in a limited manner and may be applied to any other technique belonging within the scope of the ideas of the present disclosure.

This application is based on a Japanese patent application (Japanese Patent Application No. 2019-053140) filed on March 20, 2019, the contents of which are incorporated herein by reference.

The liquid tank of the present disclosure is useful in terms of high durability.

1 Fuel tank 2 Tank body 3 Filler pipe 4 Breather pipe 21 Communication pipe 22 Bag-shaped body 30 Spherical part 31 Mouth

Claims

With the tank body
A filler pipe connected to the tank body and for injecting a liquid into the tank body,
A breather pipe connected to the tank body and the filler pipe for discharging gas in the tank body when a liquid is injected.
A communication pipe connected to the tank body and communicated with the inside of the tank body,
An elastically expandable and contractible rubber bag-like body arranged outside the tank body and communicating with the inside of the tank body via the communication pipe.
Liquid tank with.
The liquid tank according to claim 1, wherein the bag-shaped body has a spherical portion and a mouth portion protruding outward in the radial direction from the spherical portion.
The liquid tank according to claim 1, wherein the bag-shaped body has a cylindrical shape with one end closed and the other end open.
The liquid tank according to any one of claims 1 to 3, wherein the opening on the inner side of the tank body of the communication pipe is located at a position higher than the opening on the tank body side of the breather pipe.