JPH0532337Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a fuel tank device installed in a vehicle, and more particularly, to a device having a function of preventing a pressure increase in the fuel tank.

(Prior Art) Conventionally, in this type of fuel tank device, evaporated fuel gas accumulated in the upper part of the fuel tank is guided to a canister through an evaporation pipe, and the liquid fuel is removed by the canister. It is being done. In that case, for example,
In the method disclosed in the above publication, a plurality of evaporative pipes are provided, and each of them is opened near the opposing side walls of the fuel tank, so that when the vehicle turns, the liquid fuel in the tank is spread vertically, horizontally, and horizontally. Or, even if the opening of one evaporative pipe is submerged in liquid fuel and becomes blocked due to the liquid level in the fuel tank tilting back and forth, the opening of the other evaporative pipe remains open and the evaporative fuel is is released to the canister side.

(Problems to be Solved by the Invention) In this conventional system, when the canister cannot be placed directly above the fuel tank due to the layout, the lengths of the plurality of evaporative pipes are different from each other. Therefore, when the fuel liquid level in the fuel tank slopes so as to block the open end of the short pipe leading to the canister, instead of the evaporated fuel being discharged from the long pipe, the pressure inside the tank increases. Liquid fuel may flow directly into the canister from the shorter pipe.

An object of the present invention is to prevent fuel from flowing into the canister from a short evaporative pipe due to an increase in tank internal pressure even if the fuel liquid level in the fuel tank is inclined.

(Means for Solving the Problems) For the above purpose, in the vehicle fuel tank device of the present invention, the opening ends into the fuel tank of the plurality of evaporative pipes connecting the fuel tank and the canister are connected to the mutually opposing side walls of the tank. It is located nearby,
When the pipes have different lengths, the inner diameter of the evaporative pipe with the longer length is made larger than the inner diameter of the shorter evaporative pipe.

(Function) With the above configuration, when the pressure inside the fuel tank increases due to temperature changes, the evaporated fuel inside the fuel tank is released to the canister side via each evaporation pipe, which increases the pressure inside the fuel tank. rising is prevented. Since there are multiple evaporative pipes, and their open ends are placed opposite each other near the side walls of the fuel tank, the liquid level of the fuel in the fuel tank will be inclined when the vehicle turns, etc. As a result, even if one side of the tank rises, the other side falls, and the opening of one of the evaporative pipes is opened into the evaporated fuel above the liquid level, thereby ensuring prevention of pressure rise in the fuel tank.

At this time, since the inner diameter of the long evaporative pipe is larger than that of the short pipe, the flow resistance of fuel in the long evaporative pipe becomes large.
It will be smaller in short pipes. For this reason, even if the internal pressure of the tank increases, the liquid fuel in the evaporative pipe on the shorter side of the piping becomes difficult to flow into the canister. Fuel is smoothly discharged into the canister and the internal pressure of the tank can be lowered.

(Example) Next, an example of the present invention will be described based on the drawings.

In FIGS. 1 and 2, reference numeral 1 denotes a fuel tank disposed below the floor of a vehicle body, and liquid fuel (gasoline) is introduced into the fuel tank 1 through a filler pipe 2 and stored therein. Although illustration of the liquid fuel stored in the fuel tank 1 is omitted,
By operating the fuel supply pump, fuel is appropriately supplied to the intake system of the engine via the fuel supply passage.

3 is a pressure tank, inside of which the lower side is 2
It is separated into two gas-liquid separation chambers 3a and 3b, and the upper side constitutes a common chamber 3c. The above gas-liquid separation chamber 3
At the bottoms of fuel tanks a and 3b, there are first and second holes having openings 5a and 5b at one end in the fuel tank 1, respectively.
The other end openings of the evaporative pipes 5 and 6 are connected to each other. Further, the upper part of the pressure tank 3 is connected to a canister 8 via a pipe 7, and is configured to send the evaporated fuel in the tank 7 to the canister 8 via the pipe 7.

Therefore, the evaporated fuel accumulated in the upper space of the fuel tank 1 due to vaporization of the liquid fuel is transferred to the fuel tank 1.
It is discharged from the fuel tank 1 through the evaporative pipes 5 and 6, collected at one end in the pressure tank 3, and when the pressure in the fuel tank 1 is high, it is discharged from the upper part of the canister 8.
I am trying to send it to. Incidentally, the evaporated fuel guided to the canister 8 is adsorbed and liquefied, and then supplied to the intake system of the engine.

Fuel tank 1 for the above two evaporative pipes 5 and 6
The inward opening ends 5a and 6a are arranged near the side walls 1a and 1b of the upper part of the fuel tank 1, which face each other. This structure prevents the surface of the liquid fuel in the fuel tank 1 from tilting when the vehicle turns, etc.
Even when rocking, the pressure tank 3 communicates with the upper space within the fuel tank 1 via either of the two evaporation pipes 5, 6.

The first evaporative pipe 5 has an inner diameter of 6 mm, for example, and has an open end 5 located near the pressure tank 3.
a, and the upper wall 1 of the tank 1 near the opening end 5a
c is bulged upward, and the upper wall 1c of the fuel tank 1
It is designed to have enough space inside.
On the other hand, the second evaporative pipe 6 has an open end 6a at a position far from the pressure tank 3, and is constructed of a pipe having a longer piping length than the first pipe 5. Also, its inner diameter is, for example
The diameter is 10 mm, which is larger than the first evaporative pipe 5. Opening end 6a of the evaporative pipe 6
The surrounding tank upper wall 1c is bulged upward,
Sufficient space is provided in the upper part of the fuel tank 1.

Further, as shown in enlarged detail in FIG. 3, a mortar-shaped evaporation plate 9 having a center hole 9a at the center of the lower end is attached to the tank upper wall 1c corresponding to the open end 6a of the second evaporator 6. A chamber 10 is formed between the evaporative plate 9 and the tank upper wall 1c, and the open end 6a of the evaporative pipe 6 is located in this chamber 10. That is,
An evaporative pipe 6 disposed within a fuel tank 1 is raised up through a center hole 9a of an evaporative plate 9, and its open end 6a opens into a chamber 10 above the center of the evaporative plate 9.

The above evaporative plate is the upper wall 1 of the fuel tank 1.
It is fixed to c by spot welding. The upper wall 1c of the tank 1 has arc-shaped bead portions 1d, 1d, . . . centered on a predetermined position, and the evaporative plate 9 has bead portions 9b, 9b, . are respectively recessed, and both bead portions 1d and 9b are welded together during welding. FIG. 4 shows the welding situation. Before assembly, the cross-sectional radius of the tank side bead portion 1d is formed smaller than the evaporative plate side bead portion 9b, and both sides are overlapped and both sides are welded with a spot gun 11. Weld. By making the cross-sectional radius of each bead portion 1d and 9b different in this way,
Both bead portions 1d and 9b can be strongly pressed together, and the sealing performance of the chamber 10 can be improved.

Further, reference numeral 12 denotes a baffle plate that serves to reinforce the fuel tank 1 and restrict the movement of liquid fuel. This baffle plate 12 has a flange portion 12a bent at its upper end, and this flange portion 12a forms an opening 6a of the evaporative pipe 6.
The lower end is attached to the lower wall 1e of the tank 1 so as to be located directly below the center hole 9a of the evaporative plate 9. In addition, in FIG. 2, 13 and 14 are other baffle plates.

Next, the operation of the above embodiment will be explained.

When the pressure inside the fuel tank 1 increases due to an increase in temperature, the evaporated fuel accumulated in the upper part of the fuel tank 1 is discharged to the pressure tank 3 via both evaporation pipes 5 and 6, and then from the tank 3 to the canister 8. Since the fuel is discharged, the pressure inside the fuel tank 1 is regulated without increasing. Then, the vaporized fuel is liquefied in the canister 8 and supplied to the intake system of the engine. Since the open ends 5a and 6a of the evaporative pipes 5 and 6 in the fuel tank 1 are located at the highest positions in the fuel tank 1, the evaporated fuel can be easily discharged to the canister 8 side.

At that time, when the vehicle is turning, etc., the surface of the liquid fuel in the fuel tank 1 is inclined or oscillated, and one of the open ends 5a and 6 of the evaporative pipes 5 and 6 is
Even when the liquid portion is at point a, the open ends 6a, 5a of the other pipes 6, 5 face the evaporated fuel gas, and thus the evaporated fuel is sent to the pressure tank 3. Even if liquid fuel enters the pressure tank 3, it is sufficiently separated into gas and liquid, and only the gas can be sent to the canister 8.

An evaporative plate 9 is disposed below the open end 6a of the second evaporative pipe 6 that is farther from the canister 8, forming a chamber 10, so that liquid fuel can be easily poured into the open end 6a. Even if they do not approach each other and the surface of the liquid fuel is inclined, the suction of the liquid fuel into the evaporative pipe 6 is suppressed. Moreover,
Since the buffle plate 12 is disposed adjacent to the lower side of the evaporative plate 9, the flow of liquid fuel in the fuel tank 1 is further restricted by the buffle plate 12. In particular, the Batsuful plate 12
Since a flange portion 12a is formed at the upper end of the evaporator plate 9, the presence of the flange portion 12a more effectively prevents liquid fuel from entering the chamber 10 from the center hole 9a at the lower end of the evaporative plate 9. .

Of the two evaporative pipes 5 and 6, the inner diameter of the longer second evaporative pipe 6 is larger than the inner diameter of the shorter second evaporative pipe 5, so the flow resistance to the pressure tank 3 is almost uniform, and the length of the piping is The flow resistance of the long evaporative pipe 6 is greater than that of the case where both inner diameters are the same, and is smaller for the shorter pipe 5. For this reason, fuel tank 1
Even if the internal pressure of the pipe increases, it becomes difficult for liquid fuel to flow from the first evaporative pipe 5 on the shorter side of the pipe through the pressure tank 3 into the canister 8. The evaporated fuel is smoothly discharged into the canister 8 through the second pipe 6, and the internal pressure of the tank 1 can be reduced.

(Effects of the invention) As explained above, according to the invention, among the plurality of evaporative pipes that connect the vehicle fuel tank and the canister, the inner diameter of the evaporative pipe that is farther from the canister and has a longer piping length is set closer to the canister. By making the inner diameter larger than the short evaporative pipe, when the liquid level in the fuel tank slopes, the evaporated fuel is smoothly released to the canister side through the long pipe, suppressing the increase in pressure in the fuel tank. It is possible to easily prevent fuel from flowing into the canister through the short evaporation pipe at a low cost, thereby preventing deterioration of the canister as much as possible.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a front view showing the overall configuration of a vehicle fuel tank device;
FIG. 2 is a plan view of the fuel tank, FIG. 3 is an enlarged sectional view taken along the line -- in FIG. 1, and FIG. 4 is a sectional view showing a procedure for welding the evaporative plate. 1... Fuel tank, 5, 6... Evap pipe,
5a, 6a...open end, 8...canister.

Claims (1)

[Scope of utility model registration request] A plurality of evaporative pipes are provided to connect a vehicle fuel tank and a canister, and the plurality of evaporative pipes have open ends into the fuel tank located near mutually opposing side walls of the tank, and have different pipe lengths. A fuel tank device for a vehicle, characterized in that the inner diameter of the evaporative pipe having a longer length is larger than the inner diameter of the shorter evaporative pipe.