JPH0322021Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a breather device for a vehicle fuel tank, and more specifically, two breather pipes are installed in a fuel tank with openings in opposite directions. related to things. This is used in the field of maintaining the breathing action of the onboard fuel tank even when the vehicle is tilted.

[Prior art]

In a fuel tank, where a space above the liquid is always secured by a ventilation pipe installed at the top of the fuel tank, part of the fuel evaporates due to heat from the engine, etc., and the pressure in the space above the liquid increases. Or, fuel is consumed and the pressure in the upper liquid space decreases. If such a phenomenon continues, in the former case, fuel may suddenly spray out when the fuel tank is opened, causing harm to the injection worker, or
In the latter case, a problem arises in that the supply of fuel to the engine is not carried out smoothly. Therefore, a breather passage is installed in the fuel tank in order to allow the fuel tank to breathe, such as regulating the pressure within the fuel tank. This passage is designed to communicate between the inside and outside of the tank on the top surface of the fuel tank, so if the fuel tank is not horizontal, that is, if the vehicle is traveling on a slope or turning, the fuel tank will also tilt and the fuel will be filled. The problem arises that the air leaks through the breather passage. In order to prevent this, a breather device was developed in which two breather pipes were opened in the fuel tank separated from each other in opposite directions, and these were communicated with a shutoff container at the upper part of the tank. There is something described in the No. In this system, the breather pipe, which communicates with the closed space formed by the upper surface of the fuel tank and the dish-shaped isolation container at its end, intersects with the lower surface of the isolation container, and its end is above the liquid level. The space is opened near the tank end. the result,
Even if the fuel tank is tilted and the fuel is unevenly distributed within the tank, the tip of one of the two breather pipes will be located within the space, so the breathing action of the fuel tank can be maintained.

However, in such a breather device, the two pipes mentioned above protrude from the bottom outer surface of the isolation container attached to the upper inner surface of the fuel tank, which makes the shape of the breather device complicated and difficult to manufacture. In addition, there is a problem in that it is not easy to handle the breather device when it is assembled into a fuel tank.

[Purpose of invention]

The present invention was devised in view of the above-mentioned problems, and its purpose is to simplify the structure of the breather without impairing its function, making it easier to manufacture, as well as improving its handling when transporting it and installing it in a fuel tank. An object of the present invention is to provide a breather device for a vehicle fuel tank that can be improved.

[Structure of the idea]

The features of the vehicle fuel tank breather device of the present invention are as follows. A vehicle fuel tank in which an appropriate length of ventilation pipe is inserted from the upper part of the fuel tank into the inside of the tank, so that a liquid space is formed inside the tank when the tank is filled with fuel. (i) A dish-shaped member having an open top and two breather pipes extending substantially parallel to each other at its bottom is attached to the lower surface of the upper wall of the fuel tank.

(ii) One end of one breather pipe is opened at an end inside the internal space of the dish-shaped member, and the other end is opened to the outside of the dish-shaped member through a side wall of the dish-shaped member.

(iii) One end of the other breather pipe is opened into the internal space of the dish-shaped member at a position close to the other end of the one breather pipe, and the other end is opened into the interior space of the dish-shaped member at a position close to the other end of the one breather pipe. It penetrates the side wall of the dish-shaped member and is opened to the outside of the dish-shaped member.

(iv) A breather passage that communicates the internal space of the dish-shaped member with the outside of the fuel tank and adjusts the pressure in the upper liquid space is provided at the upper part of the fuel tank.

〔Example〕

Hereinafter, the present invention will be described in detail based on examples thereof. FIG. 1 is a sectional view of a fuel tank 2 equipped with a breather device 1 for a vehicle fuel tank according to the present invention, in which two upper and lower tank cases 2A and 2B are joined by welding or the like to form one tank. . A fuel filler pipe 4 into which fuel 3 such as gasoline is injected into the fuel tank 2 from above.
And the ventilation pipe 5 branched to this
has been plunged an appropriate length into the fuel tank. Therefore, when the tank is full, the opening 5a of the ventilation pipe 5 is closed by the fuel 3, preventing air from escaping, preventing further injection, and creating an upper liquid space 6 inside the fuel tank. It is becoming secured. On the lower surface of the upper wall 2a of the upper case 2A of the fuel tank 2, the upper surface is open, and as shown in FIG. A plate-shaped member 8 is fixed by welding or the like, and an internal space 9 is formed between this plate-shaped member 8 and the upper wall 2a of the fuel tank 2.
The two breather pipes 7A and 7B are pipes that communicate the internal space 9 and the upper liquid space 6, and as shown in FIG. 3, one end of the pipe 7A is connected to a dish-shaped member. 8, and the other end penetrates the side wall 8a of the dish-shaped member 8 and opens to the outside of the dish-shaped member 8, as shown in FIG. 2b. Further, as shown in FIG. 2a, one end of the other breather pipe 7B is opened into the internal space 9 of the dish-shaped member 8 at a position close to the other end of the one breather pipe 7A. A dish-shaped member 8 located close to one end of the pipe 7A
It penetrates the other side wall 8b and opens to the outside of the dish-shaped member 8. A breather passage 10 for communicating the inside and outside of the tank is attached to the upper wall 2a of the fuel tank 2 on the upper surface of the dish-shaped member 8, and the inner side end of this passage is opened at the inner surface of the upper wall of the tank. , it is possible to supply and discharge air to adjust the internal pressure of the fuel tank 2.

According to an embodiment having such a configuration, it can be operated as follows. When liquid fuel 3 such as gasoline is injected from fuel filler pipe 4 and its liquid level reaches opening 5a of ventilation pipe 5, leakage is prevented by a check valve (not shown) interposed in breather passage 10. The air in the upper liquid space 6 is also prevented from flowing out from the ventilation pipe 5, making it impossible to inject any more fuel 3, and the fuel tank 2 becomes full. In such a state, if the fuel tank 2 is in a horizontal state, the breather device 1 including the dish-shaped member 8
is located in the upper liquid space 6 without being immersed in the fuel 3.

Now, when the fuel tank 2 receives heat from the engine and the amount of evaporation of the fuel 3 increases, and the pressure in the upper liquid space 6 rises, the air containing the vapor flows through the side walls 8a,
It is introduced into the internal space 9 via two breather pipes 7A and 7B that penetrate through the pipe 8b and open to the outside of the dish-shaped member 8, and when the pressure increases above a preset pressure, it enters the breather passage 10. An interposed check valve (not shown) is opened to allow the fuel to flow out, thereby avoiding an excessive rise in pressure within the fuel tank 2. On the other hand, if the fuel continues to be consumed, the liquid level will drop, the upper liquid space 6 will be expanded, and the pressure in that space will be lowered. If this pressure becomes too low, the delivery of fuel 3 to the engine will decrease, so
To facilitate this, outside air is introduced through the above-mentioned check valve.

If the fuel tank 2, in which the pressure in the upper liquid space 6 is regulated in this way, is tilted due to frequent turning, driving on a slope, or long-term stop on a slope, the fuel 3, which was horizontal, may be tilted. Each time the liquid level 11 changes into an inclined liquid level 12 or 13 as shown in FIG. At that time, a part or most of the dish-shaped member 8 constituting the breather device 1 will be immersed in the fuel 3. However, at least a portion of the dish-shaped member 8 constituting this breather device 1 remains above the liquid surface. That is, the inclined liquid level 1
In case 2, the opening of the side wall 8b of the breather pipe 7B is buried in the fuel 3;
The opening remains in the upper liquid space 6. Therefore, although fuel enters the breather pipe 7B up to the inclined liquid level 12 and air flow is blocked, the fuel itself is prevented from entering the internal space 9 of the dish-shaped member 8. On the other hand, since air communication is maintained in the breather pipe 7A, the breathing action of the fuel tank 2 is maintained. Conversely, when the liquid level is inclined as shown in 13, breathing through the breather pipe 7B becomes possible, and even if the direction of inclination of the vehicle is different, one of the pipes maintains communication with the outside of the fuel tank, so the breather device is It can function all the time.

[Effect of idea]

As can be seen from the description of the above embodiments, the present invention has the following features:
Two nearly parallel breather pipes are fixed to the bottom of a dish-shaped member attached to the upper wall of the fuel tank, and the breather pipes penetrate through the side wall so as to open in opposite directions and at separate positions. Since each other end is opened at both ends within the internal space of the dish-shaped member, the breather function is not impaired even if the fuel tank is tilted, simplifying the structure and making manufacturing easier. can do. In addition, handling during transportation and installation into a fuel tank is significantly improved.

[Brief explanation of the drawing]

Fig. 1 is a partial sectional view of a fuel tank equipped with a breather device for a vehicle fuel tank according to the present invention;
Figure a is a view taken from the - line in Figure 1, Figure 2 b is a view seen from the - line in Figure 2a, and Figure 3 is a view seen from the - line in Figure 2 a.
FIG. 2... Fuel tank, 2a... Upper wall, 3... Fuel, 5... Ventilation pipe, 6... Upper liquid space, 7A, 7B... Breather pipe, 8... Dish-shaped member, 8a, 8b ...Side wall, 9...Interior space,
10...breather passage.

Claims (1)

[Scope of utility model registration request] In a vehicle fuel tank, a ventilation pipe is inserted from the upper part of the fuel tank to the inside of the tank to an appropriate length so that a liquid space is formed inside the tank when the tank is filled with fuel. A dish-shaped member having an open top surface and two freezer pipes extending substantially parallel to each other fixed to the bottom thereof is attached to the lower surface of the upper wall of the fuel tank, and one end of the one breather pipe is attached to the dish-shaped member. and the other end thereof is opened to the outside of the dish-shaped member through the side wall of the dish-shaped member, and one end of the other breather pipe is opened at the other end of the one breather pipe. is opened into the internal space of the dish-shaped member at a position close to the one end of the dish-shaped member, and the other end is opened to the outside of the dish-shaped member through a side wall of the dish-shaped member located close to one end of the one breather pipe, A breather device for a fuel tank for a vehicle, characterized in that a breather passage that communicates the internal space of the dish-shaped member with the outside of the fuel tank and adjusts the pressure in the above-mentioned liquid space is disposed in the upper part of the fuel tank. .