JPH0532333Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a fuel tank having a float valve installed in an internal combustion engine or the like.

(Prior art) As shown in Japanese Patent Publication No. 10301/1983, a conventional fuel tank has a structure in which a float valve with a perforated float arranged in a float chamber is attached to the upper wall of the fuel tank. The float valve is connected to the breather passage. The float valve used herein has a fuel vent eyelet and an inlet hole in the float chamber containing the float.

When the fuel tank is filled with fuel and reaches a predetermined fuel level, the float comes into contact with the upper wall of the float chamber.

(Problem to be solved by the invention) The float in the float valve has a hole, and even if it comes into contact with the upper wall of the float chamber, the breather passage in the float chamber will be connected, which will prevent fuel supply. Unable to prevent overfilling. This problem can be solved if the float is not perforated, but in this case, the following problem arises. In other words, with this structure, when the float comes into contact with the upper wall of the float chamber, communication between the inside of the tank and the breather passage is cut off, and the inside of the tank is not ventilated, causing fuel to rise above a predetermined height below the contact level of the float. Not supplied. Therefore, although overfilling is prevented, if you want to store as much fuel as possible in the tank, the purpose will not be achieved unless you make changes such as increasing the size of the fuel tank.

(Means for Solving the Problem) The present invention forms a float chamber using an upper case in which a small hole is provided between a first sealing surface and a second sealing surface, and a lower case in which a restriction hole is provided in the bottom wall. and a float valve formed by a first float and a second float slidably fitted in the first float is installed in the fuel tank in communication with the ventilation pipe. .

(Operation) When fuel is supplied into the fuel tank, fuel vapor flows from the opening of the float valve to the ventilation pipe. When the liquid level rises across the float valve, the first float floats and abuts the first sealing surface. Then, the liquid level rises through the fuel supply pipe, reaches the refueling nozzle, and stops refueling. Fuel vapor continues to flow into the ventilation pipe from the small hole in the upper case, making additional refueling possible, and the liquid level rises again due to refueling, causing the second
The float floats and contacts the second seal surface, stopping oil supply.

(Example) Fig. 1 shows a fuel tank 1 having a float valve, a fuel supply pipe 3 on the side wall of the tank 2, a ventilation pipe 4 on the upper wall of the tank 2, and a lower end of the ventilation pipe 4. A float valve 5 is connected to the float valve 5. The upper end of the ventilation pipe 4 is connected to a steam pipe 6 which is connected to the upper end of the fuel supply pipe 3 and connected to a fuel vapor adsorption container (not shown). 7 is fuel supply pipe 3
It is a filler cap that closes the upper opening of the

The float valve 5 includes a float 13 disposed within a float chamber 10 formed by upper and lower cases 11 and 12, as shown in FIG. The upper case 11 has an annular inclined wall 16 in which a first sealing surface 14 with a large diameter and a second sealing surface 15 with a small diameter are continuously formed.
At the upper part of the second sealing surface 15 there is a connecting pipe 17, and at the lower part of the first sealing surface 14 there is an annular flange 1.
8 are provided respectively. There are a plurality of small holes 19 between the first sealing surface 14 and the second sealing surface 15 and a plurality of openings 20 directly above the annular flange 18.
are drilled in each. The lower case 12 has a cylindrical shape with a closed lower surface and an open upper surface, and a restriction hole 21 is provided on the closed surface.
An annular flange 18a having the same diameter as the upper case 11 is provided at the upper end. float 13
consists of a first float 22 and a second float 23, the first float 22 is made of cylindrical synthetic resin, has a specific gravity smaller than that of fuel oil such as gasoline or diesel oil, has a flat bottom surface, and has a flat top surface. is spherical. Furthermore, a circular through hole 24 is provided in the center of the first float 22 in a vertical direction. The second float 23 is made of mushroom-shaped synthetic resin and consists of a seal part 25 and a float part 26.
The upper end of 5 is spherical, and a float portion 26 is provided on the lower surface thereof. The float part 26 is fitted into the through hole 24 with a diameter smaller than that of the through hole 24 of the first float 22, and is slidable in the vertical direction.

Remove the cap 7 of the fuel supply pipe 3 and insert the fuel nozzle to supply fuel to the fuel tank 2. In the early days of automatic refueling, a large amount of fuel flowed into the tank from the refueling nozzle, creating a large amount of fuel vapor inside the tank. This fuel vapor passes through the opening 20 of the float valve 5, the ventilation pipe 3 and the steam pipe 6, and reaches the fuel vapor adsorption container where it is adsorbed by an adsorbent.
When the liquid level reaches the float valve 5 and enters the float chamber 10 through the restriction hole 21 of the lower case 12,
The float 13 floats as the liquid level rises. At this time, fuel vapor flows from the opening 20 into the ventilation pipe 4.
Since the flow toward , acts to push the top of the float 13 downward, it rises relatively slowly. When the liquid level further rises and the upper circumference of the first float 22 comes into contact with the first sealing surface 14 of the upper case 11, the fuel vapor will flow into the ventilation pipe 4 only through the small hole 19. The liquid level cannot rise in the tank 2, and the fuel rises up the fuel supply pipe 3 and reaches the tip of the fuel nozzle, stopping fuel supply. The fuel vapor continues to flow from the small hole 19 of the upper case 11, and the fuel vapor continues to flow from the small hole 19 when additional refueling is performed. flows into the ventilation pipe 4, the liquid level rises, and the second float 23 floats. and the second
Seal portion 25 of float 23 and second seal surface 1
5 makes contact, the fuel vapor in the tank 2 has nowhere to escape and the liquid level rises again through the fuel supply pipe 3 and reaches the tip of the fuel supply nozzle, stopping fuel supply.

As another embodiment, as shown in FIG. 3, the lower case 31
An annular inclined wall 32 is provided on the bottom surface of the float chamber 10 facing inward, a sphere 33 is disposed on the annular inclined wall 32, and the lower surface of the first float 34 in the float chamber 10 is formed into an umbrella shape. 35 is a through hole provided in the upper part of the first float 34. The shapes of the upper case and second float remain unchanged. In this case, when the vehicle tilts or falls over, the sphere 33 rolls on the annular inclined wall 32 and presses the lower surface of the first float 34 to come into contact with the sealing surface.

(Effect of the invention) As described above, the present invention has a first sealing surface and a second sealing surface.
A float chamber is formed by an upper case with a small hole between the sealing surfaces and a lower case with a restriction hole in the bottom wall. Since it is attached to the tank, after the initial refueling is stopped by the first float in contact with the first sealing surface, additional refueling is possible by continuing to flow fuel vapor through the small hole, allowing a large amount of fuel to be supplied without changing the tank capacity. can be stored. The second float also prevents overfilling with fuel.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a fuel tank with a float valve, Figure 2 is a sectional view of the float valve, and Figure 3 is a sectional view of a fuel tank with a float valve.
The figure is a sectional view of a float valve of another embodiment. 3... Fuel supply pipe, 4... Ventilation pipe, 5... Float valve, 11... Upper case, 12, 31... Lower case, 13... Float, 14... First sealing surface, 15... Second sealing surface, 19...Small hole, 2
0...Opening, 21...Restriction hole, 22, 34...First float, 23...Second float.

Claims (1)

[Scope of utility model registration request] A float chamber is formed by an upper case in which a small hole is provided between the first sealing surface and the second sealing surface, and a lower case in which a restriction hole is provided in the bottom wall.
A float valve equipped with a float consisting of a float and a second float slidably fitted to the first float is attached to the upper wall of the fuel tank, and the float valve is connected to the ventilation pipe. Has a fuel tank.