JPH0557924B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a vapor discharge device for a fuel tank for an automobile.

Conventional Technology In the case of automobile fuel tanks, the vapor discharge tube is used to prevent vapor generation from increasing the internal pressure of the tank, interfering with fuel supply or deforming the tank body. The vapor is drawn out of the tank body and guided into the canister, where it is supplied along with purge air to the engine intake passage.
I'm trying to process it. This will be explained with reference to FIG. 4. Reference numeral 20 indicates a tank body, and a separator chamber 21 is disposed in an upper space S within the tank body 20. Communication holes 22 and 23 are formed in the bottom wall and the upper part of the peripheral wall of this separator chamber 21, and a vapor pipe 24 that penetrates the upper wall of the tank body 20 and projects outside the tank body is arranged in the upper wall. A vapor outlet tube 25 is connected to the vapor pipe 24, which communicates with a canister (not shown). The vapor pipe 24 is set at a position that is higher than the liquid level in the tank even when the vehicle is making a sharp turn when the vehicle is full of fuel or when the vehicle body is tilted to its maximum.

According to this conventional device, when the tank body 20 is in a horizontal state substantially parallel to the liquid level in the tank shown by the solid line, the generated vapor flows into the separator chamber 21 through the communication holes 22 and 23 and is transferred to the tank via the vapor pipe 24. Vapor outlet tube 2 pulled out from the main body 20
5 to a canister (not shown). When the vehicle tilts to the maximum right or makes a sharp turn to the left, the communication hole 22 will be submerged in the liquid level in the tank shown by line A in Figure 4, but the communication hole 23 and vapor pipe 24 will be lower than the liquid level. Also, if the vehicle leans to the maximum left or turns sharply to the right, the communication holes 22 and 23 will be submerged in the liquid level in the tank as shown by the line B in Figure 4, but the vapor pipe 24 is intended to be secured above the liquid level, and in any case to avoid direct flow of fuel into the vapor pipe 24 due to liquid movement. This similar structure is shown in, for example, Japanese Utility Model Publication No. 47-24496.

Problems to be Solved by the Invention Although it is possible to avoid fuel flowing directly into the vapor pipe 24 due to liquid movement when the vehicle is at its maximum inclination or when making a sharp turn, the communication holes 22 and 23 are
When the tank is parked for a long time submerged in the liquid level in the tank as shown by the black line in the figure, if the internal pressure of the tank body 20, that is, the pressure in the upper space S increases with the generation of vapor, this pressure increase will cause the fuel to The fuel is pushed up into the separator chamber 21, the liquid level within the separator chamber 21 rises, and the fuel flows into the vapor pipe 24,
There is a risk that fuel may leak out of the tank body. For this reason, the volume of the separator chamber 21 should be made as large as possible, and the tank body 21 should be made as large as possible.
It has been pointed out that the tank body 20 needs to be disposed above the liquid level when the tank body 20 is full, which reduces the effective volume of the tank body 20.

SUMMARY OF THE INVENTION Therefore, the present invention provides a vapor discharge device for an automobile fuel tank that can reliably prevent fuel from flowing out without reducing the volume of the tank body.

Means for solving the problem A separator chamber having an orifice formed in the corner of the upper wall of the tank body is provided, and a first vapor pipe along one side of the upper wall of the tank body is connected in communication with this separator chamber. and disposing one end opening of the pipe above the side facing the separator chamber, while a second vapor pipe is connected in communication above the separator chamber, and one end opening of the pipe is disposed to protrude outside the tank body, Further, a third vapor pipe is connected in communication with the separator chamber, and one end opening of the pipe is disposed at a corner of the upper wall of the tank body on a diagonal line of the separator chamber.

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

In FIGS. 1 to 3, bulges 3A and 3B are formed on one side of the upper wall 2 of the tank body 1, for example, at the left and right corners of the rear portion of the upper wall. 6A shows a paper discharge device disposed in the upper space S of the tank body 1, and includes a separator chamber 12 and a paper discharge device disposed in the upper space S of the tank body 1.
Three vapor pipes 13, 14,
It consists of 15. The separator chamber 12 has an orifice 12a formed in its upper wall, and is disposed in one of the bulges, for example, the bulge 3A on the right side of the tank body 1. The first vapor pipe 13 is connected to the lower part of the circumferential side wall of the separator chamber 12 with an appropriate slope, and has one end opening 13a facing the side of the other bulging part 3B facing the one bulging part 3A. It is arranged in a curved manner at the top of the section. 2nd vapor pipe 1
4 is connected to the separator chamber 12 by penetrating its circumferential side wall, and has one end opening 14a protruding outside the tank body 1, while the other end opening 14b is connected to the separator chamber 1.
It is arranged bent above 2. The second vapor pipe 14 may be connected to the upper wall of the separator chamber 12 or to the upper part of the circumferential wall instead of penetrating the circumferential wall of the separator chamber 12 for communication. The third vapor pipe 15 is connected to the bottom of the separator chamber 12, specifically, to the bottom wall of the separator chamber with an appropriate slope, and has an opening 15 at one end.
a is arranged at a corner of the tank body 1 on a diagonal of the separator chamber 12.

Next, the operation of the apparatus of the above embodiment will be explained. When the tank body 1 is in a horizontal state parallel to the liquid level in the tank as shown by the solid line in FIGS. 2 and 3, the generated paper flows through the first vapor pipe 13 and the third vapor pipe 15.
The vapor enters the separator chamber 12 through the openings 13a and 15a at each end, and is guided from the second vapor pipe 14 to a canister (not shown) via the vapor outlet tube 11 connected to the second vapor pipe 14.

When the vehicle body is tilted to the maximum to the right or to the left, for example, when the vehicle body is tilted to the maximum to the right, one end opening 15a of the third vapor pipe 15 is submerged in the liquid level in the tank as indicated by the chain line a in FIG. Since the opening 13a at one end of the first vapor pipe 13 is located above the liquid level in the tank, the generated paper can be efficiently discharged as described above. When the vehicle body returns to its original state, the fuel that has flowed halfway into the third vapor pipe 15 immediately flows down because the third vapor pipe 15 has an appropriate slope. Conversely, if the vehicle body tilts to the left to the maximum, the first vapor pipe 1
3. One end opening 13 of each third vapor pipe 15
Since points a and 15a are located above the liquid level in the tank indicated by the chain line b in FIG. 2, the generated vapor can be properly discharged in this case as well, as described above. When the vehicle body is tilted forward to the maximum, the opening 15a at one end of the third vapor pipe 15 is submerged below the liquid level in the tank as indicated by the chain line c in FIG. 3, but the first vapor pipe 13 and separator chamber 12 are Since it is located higher than the above, there is no problem in discharging the generated vapor. Conversely, when the vehicle body tilts backward to the maximum, the one end opening 15a of the third vapor pipe 15 is located above the liquid level in the tank indicated by the chain line d in FIG. 3, and the one end opening 13a of the first vapor pipe 13 Since it is located above the liquid level in the tank together with the separator chamber 12,
As with forward tilting, there is no problem in discharging vapor. Next, when the vehicle makes a sudden turn, for example to the right, the openings 13a and 15a of the first vapor pipe and the third vapor pipe 15 sink below the liquid level in the tank as indicated by the chain line e in FIG. , the separator chamber 12 is located above the liquid level, and
Since the separator chamber 12 and the space S are in communication with each other through the orifice 12a and there is almost no pressure difference, no fuel flows into the separator chamber 12 at all.
When the turning run is completed, the first vapor pipe 13 has an appropriate slope, so the first vapor pipe 13
The fuel that has flowed halfway into the separator chamber 12 flows into the separator chamber 12, but the amount of fuel that flows in is extremely small. Since the orifice 12a is connected to the bottom wall and is formed on the upper wall of the separator chamber 12, the fuel flowing into the separator chamber 12 can be quickly caused to flow down. The fuel that has flowed halfway into the third vapor pipe 15 also immediately flows down. Conversely, if the vehicle turns sharply to the left, the first vapor pipe 1
3. One end opening 13 of each third vapor pipe 15
Since both of a and 15a are located above the liquid level in the tank indicated by the chain line f in FIG. 2, the inflow of fuel into the separator chamber 12 is limited to the orifice 12a, and the amount of inflowing fuel is extremely small. Furthermore, when the vehicle suddenly starts, the one end opening 13a of the first vapor pipe 13 and the orifice 12a of the separator chamber 12 are submerged below the liquid level in the tank as shown by the chain line g in FIG. Since the fuel is above the liquid level and this condition is instantaneous, the amount of fuel flowing into the separator chamber 12 is extremely small, and there is no problem. Also, when the vehicle suddenly stops,
One end opening 15a of the third vapor pipe 15 is submerged below the liquid level as indicated by the chain line h, but since the separator chamber 12 is above the liquid level, no fuel flows into the separator chamber 12 at all.

As described above, according to this embodiment, the separator chamber 1
2 will not be filled with fuel, therefore,
This makes it possible to reliably prevent fuel from flowing out. Furthermore, the separator chamber 12 can be made as small as possible, taking into consideration the small amount of fuel flowing in when the fuel liquid moves, so the space it occupies within the tank body 1 is extremely small.
It also does not reduce the effective volume of the

In the embodiment, a pair of left and right bulges are provided on the upper wall at the rear of the tank body. They may be formed at the front and rear.

Effects of the Invention As described above, according to the present invention, fuel can be reliably prevented from flowing out of the tank and vapor can be discharged.
Furthermore, since the separator chamber can be made as small as possible, the effective volume of the tank body is not reduced, which is a great practical effect.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention, FIG.
3 is a schematic cross-sectional explanatory view seen from the arrow direction and the arrow direction of FIG. 1, respectively, and FIG. 4 is a schematic cross-sectional explanatory view showing a conventional device. 1... Tank body, 2... Tank body upper wall, 6
A... Vapor discharge device, 12... Separator chamber,
12a... Orifice, 13... First vapor pipe, 13a... One end opening, 14... Second vapor pipe, 14a... One end opening, 15... Third vapor pipe, 15a... One end opening.

Claims (1)

[Claims] 1. A separator chamber with an orifice formed in the upper wall is provided at a corner of the upper wall of the tank body, and a first vapor pipe along one side of the upper wall of the tank body is connected in communication with the separator chamber, so that the pipe is one end opening is disposed above the side facing the separator chamber, a second vapor pipe is connected above the separator chamber so that the one end opening of the pipe protrudes outside the tank body; A paper discharge device for an automobile fuel tank, characterized in that a third vapor pipe is communicatively connected to the chamber, and an opening at one end of the pipe is disposed at a corner of an upper wall of the tank body diagonally of the separator chamber. .