JP3566059B2 - Vehicle fuel tank - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a structure of a fuel tank for a vehicle, and in particular, adjusts a position of a cut-off valve provided on a ceiling wall of the fuel tank so that the outflow pressure of the fuel is equal to or higher than a predetermined pressure even when the vehicle body is in any overturned state. The present invention relates to a vehicle fuel tank capable of improving safety against fuel leakage.
[0002]
[Prior art]
In general, the fuel tank is arranged at the rear of the vehicle body, and the fuel evaporated in the fuel tank is temporarily absorbed by a canister arranged in the engine room at the front of the vehicle body through an evaporative line connected to the ceiling wall. It is configured to be stored and inhaled when the engine is started.
[0003]
This will be described with reference to FIG. FIG. 3 shows a state in which the front is viewed from the rear of the vehicle body. Reference numeral 21 denotes a fuel tank, reference numeral 22 denotes a canister, reference numeral 23 denotes an evaporative line. ing. In order to prevent the fuel in the fuel tank 21 from leaking from the atmosphere opening port 22a through the evaporative line 23 and the canister 22 when the vehicle rolls over, a cut-off valve is provided on the ceiling wall substantially at the center of the fuel tank 21. The evaporative line 23 is connected to the cutoff valve 24. Further, in order to prevent the fuel tank 21 from bursting when the internal pressure rises abnormally due to tank deformation or the like with the float of the cutoff valve 24 closed, a relief valve 25 is attached to the cutoff valve 24. Have been. The configuration in which the relief valve 25 is attached to the cutoff valve 24 in this manner is known, for example, from Japanese Utility Model Laid-Open No. 3-73657 and Japanese Utility Model Laid-Open No. 4-48024. The canister 22 is also provided with a two-way valve 26 that opens at a certain pressure or higher to open the inlet of the canister 22.
[0004]
In the above configuration, the pressure at which the relief valve 25 opens is P ₁ , the pressure at which the two-way valve 26 opens is P ₂ , the head difference between the liquid surface Sr and the two-way valve 26 during right-side rollover is P ₃ , and the left-side rollover. Assuming that the head difference between the liquid level S1 and the two-way valve 26 at the time is P ₄ , and the head difference between the liquid level Sv and the two-way valve 26 at the time of 180 ° inversion is P ₅ , the inside of the fuel tank 21 is When the pressure becomes equal to or higher than the following pressure, the fuel flows out from the atmosphere opening port 22a of the canister 22.
[0005]
In the case of P ₁ ≧ P ₂ (1) Outflow at the pressure of (P ₁ + P ₃ ) at right rollover (2) Outflow at the pressure of (P ₁ -P ₄ ) at left rollover (3) , _(P 1 -P ₅₎ when the outlet _P 1 _{<P 2} at a pressure of (1) at right rollover _{is, (P} 2 + _{P 3)} outflow (2) at the left rollover pressure _{of, (P} 2 -P ₄ ) Outflow at pressure (3) At reversal, outflow at pressure (P ₂ -P ₅ )
[Problems to be solved by the invention]
However, when the right rollover in the above _{configuration, (P} 1 + P ₃₎ and _(P 2 ₊ P 3) _(e.g., 1000 + 300 = 1300mmAq) but the high pressures that does not act no fuel flows out, at the time of the left rollover, _{(P 1} - Even when a low pressure such as P ₄ ) or (P ₂ −P ₄ ) (for example, 1000−400 = 600 mmAq) is applied, fuel may flow out, and the safety against fuel leakage is reduced. There was a problem that it was influenced by the.
[0007]
SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described conventional problems, and has as its object to provide a vehicle fuel tank structure that can ensure safety against fuel leakage regardless of the posture of the vehicle when the vehicle falls.
[0008]
[Means for Solving the Problems]
The fuel tank for a vehicle according to the present invention is a fuel tank for a vehicle in which a fuel tank communicates with a canister disposed on one side in a vehicle width direction through a cutoff valve and an evaporative line disposed on a ceiling wall thereof. The cut-off valve is disposed above the liquid level of the fuel tank when the vehicle is rolled over to the canister arrangement side when the fuel tank is full , and the cut-off valve is disposed in any of the left and right directions. However, a pressure equal to or more than the sum of the valve opening pressure of the relief valve or the two-way valve disposed on the canister and the head differential pressure between the two-way valve and the liquid level disposed on the canister. Until the fuel does not flow out, or the cut-off valve is located above the liquid level and the fuel does not flow out, so that safety against fuel leakage can be improved.
[0009]
In addition, by providing a bulging portion protruding on the side opposite to the canister arrangement side or a bulging portion protruding upward from the cutoff valve arrangement portion at the upper part of the fuel tank, the liquid level when 180 ° is inverted is provided. As the head differential pressure decreases, the outflow pressure increases and the safety against fuel leakage increases. In addition, when the cutoff valve is positioned to be offset as described above, dynamic fuel leakage from the cutoff valve is likely to occur due to the liquid level inclination when the vehicle turns in the direction opposite to the offset direction, and as a result, It is necessary to reduce the specified amount (so-called full tank capacity) of the fuel tank. However, the provision of the bulging portion lowers the liquid level, thereby preventing this dynamic fuel leakage, and reducing the fuel tank. The specified amount (full tank capacity) can be maintained.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, one embodiment of a vehicular fuel tank of the present invention will be described with reference to FIGS.
[0011]
In FIG. 2 showing the arrangement of the fuel tank and the canister, the fuel tank 1 is arranged on the left side of the rear part of the vehicle 10, and the canister 2 is arranged on the left side member of the engine room 11 at the front part of the vehicle 10. The tank 1 and the canister 2 are connected by an evaporation line 3. Reference numeral 4 denotes a fuel for preventing the fuel in the fuel tank 1 from leaking to the outside through the evaporative line 3 and the canister 2 when the vehicle 10 falls down and rolls over from side to side or when the vehicle 10 turns over by 180 °. This is a cut-off valve provided on the ceiling wall of the tank 1, and the evaporative line 3 is connected to the inside of the fuel tank 1 via the cut-off valve 4. In FIG. 2, reference numeral 8 denotes a fuel pump unit, and reference numeral 9 denotes a fuel supply pipe.
[0012]
1A and 2, the canister 2 is located on the left side of the center line O in the vehicle width direction of the fuel tank 1, whereas the cutoff valve 4 is located on the side where the vehicle 10 is disposed on the canister 2. The fuel tank 1 is disposed so as to be located above the liquid level Sl when a predetermined amount (full tank capacity) of the fuel tank 1 is turned to the left. 2a is an air opening of the canister.
[0013]
In FIG. 1A, a cutoff valve 4 is provided to prevent the fuel tank 1 from bursting when the internal pressure rises abnormally due to tank deformation or the like in a state where the float is closed as the vehicle falls. A relief valve 5 is provided, and a two-way valve 6 is also provided on the canister 2 to open at a certain pressure or higher and communicate with an inlet of the canister 2. In addition, a bulging portion 7 is formed at the upper portion on the right side of the fuel tank 1 where the cutoff valve 4 is disposed, so as to protrude from the conventional right wall surface 1a indicated by a virtual line.
[0014]
The pressure at which the relief valve 5 opens is set at P ₁ , and the pressure at which the two-way valve 6 opens is set at P ₂ . The head difference between the fuel level Sr in the fuel tank 1 and the two-way valve 6 when the vehicle 10 rolls over to the right when the fuel is in the full state with the specified amount of fuel is P ₃ , and when the vehicle is turned 180 °. head difference between the liquid surface Sv and the two-way valve 6 is P _5. Ss is the liquid level when the vehicle makes a left turn, and Ss ′ is the liquid level in the same state as in the case of the conventional fuel tank 21 having no bulging portion 7.
[0015]
In the above configuration, when the pressure inside the fuel tank 1 becomes equal to or higher than the following pressure, the fuel flows out from the atmosphere opening port 2a of the canister 2.
[0016]
In the case of P ₁ ≧ P ₂ (1) Outflow at the pressure of (P ₁ + P ₃ ) during right rollover (2) No outflow during left rollover because the cutoff valve 4 is located above the liquid level Sl ( 3) during _inversion, the outflow pressure of _(P 1 -P _5).
[0017]
As described above, according to the present embodiment, the cut-off valve 4 is prevented from being submerged during the left rollover in which the fuel flows out at a low pressure in the past. Sex can be further enhanced. Further, the liquid level Sv since the bulging portion 7 is provided at the top of the fuel tank 1 decreases even during reversing, outflow pressure because P ₅ is smaller than the conventional (P 1 _{-P 5)} is higher, the fuel leakage Is more secure. Further, since the bulging portion 7 is provided on the upper right side of the fuel tank 1, the liquid level Ss inclined when the vehicle turns left becomes lower than the conventional liquid level Ss'. In addition to preventing the fuel from leaking, the specified amount (full capacity) of the fuel tank 1 can be maintained.
[0018]
In the above description, the case where P ₁ ≧ P ₂ has been described. However, when P ₁ <P ₂ , the operation is the same as that described above, except that the above P ₁ is changed to P ₂ .
[0019]
In the above description, the case where the canister 2 is disposed on the left side of the center line O of the fuel tank 1 has been described. However, depending on the arrangement position of the canister 2, as shown in FIG. When the canister 2 is disposed on the right side of the center line O of the fuel tank 1, the cutoff valve 4 sets the cutoff valve 4 above the liquid level Sr of the fuel tank 1 when the vehicle 10 rolls over to the right at the specified amount. What is necessary is just to arrange so that it may be located above. At this time, when the pressure in the fuel tank 1 becomes equal to or higher than the following pressure, the fuel flows out from the atmosphere opening port 2a of the canister 2.
[0020]
In the case of P ₁ ≧ P ₂ (1) When the vehicle rolls over to the right, the cut-off valve 4 is located above the liquid level Sr and does not flow out. (2) When the vehicle rolls over to the left, it flows out at a pressure of (P ₁ + P ₃ ) ( 3) during _inversion, the outflow pressure of _(P 1 -P _5).
[0021]
Also in this case, the operation is basically the same as that described above, except that the left and right are reversed from the case of FIG. Also, in the case of P ₁ <P ₂ , the operation is the same as described above, except that P ₁ is changed to P ₂ .
[0022]
In the above-described embodiment, an example is shown in which the bulging portion 7 bulges out on the side opposite to the side where the canister 2 is arranged. However, the arranging portion of the cutoff valve 4 may bulge upward. .
[0023]
【The invention's effect】
According to the present invention, as described above, the cutoff valve is disposed so as to be located above the liquid level at the time of full capacity of the fuel tank when the vehicle is rolled over to the canister arrangement side. Regardless of the rollover in any direction, the valve opening pressure of the relief valve or the two-way valve provided on the canister and the head differential pressure between the two-way valve and the liquid level are provided. The fuel does not flow out until the pressure becomes equal to or higher than the sum of the above, or the cut-off valve is located above the liquid level and the fuel does not flow out, so that safety against fuel leakage can be improved.
[0024]
In addition, when a bulging portion that protrudes on the opposite side to the canister arrangement side or a bulging portion where the cutoff valve arrangement portion protrudes upward is provided at the upper part of the fuel tank, the liquid level height when inverted by 180 ° is provided. And the head differential pressure is reduced, the outflow pressure is increased, the safety against fuel leakage is increased, and the cut-off is caused by the liquid level inclination when the vehicle turns in the direction opposite to the one-sided direction of the cut-off valve. Dynamic fuel leakage from the valve can be prevented from easily occurring, and a specified amount (full capacity) of the fuel tank can be maintained.
[Brief description of the drawings]
1A and 1B show an arrangement positional relationship between a fuel tank, a canister, and a cutoff valve in an embodiment of a vehicle fuel tank according to the present invention, wherein FIG. 1A is an explanatory diagram of an example in which a canister is located on the left side, and FIG. FIG. 4 is an explanatory diagram of an example in which a canister is located on the right side.
FIG. 2 is a plan view showing an arrangement position of a fuel tank and a canister on the vehicle body in the embodiment.
FIG. 3 is an explanatory diagram of a positional relationship between a fuel tank, a canister, and a cutoff valve in a conventional vehicle fuel tank.
[Explanation of symbols]
Reference Signs List 1 fuel tank 2 canister 3 evaporation line 4 cut-off valve 5 relief valve 6 2 way valve 7 bulging portion

Claims (2)

In a fuel tank for a vehicle in which a fuel tank communicates with a canister provided on one side in a vehicle width direction through a cutoff valve provided on a ceiling wall of the fuel tank and an evaporative line, a cutoff valve is provided. A fuel tank for a vehicle, wherein the tank is disposed above a liquid level of the fuel tank when the fuel tank is overturned to the arrangement side when the tank is full . 2. The vehicle fuel according to claim 1, wherein a bulge protruding in a direction opposite to the canister arrangement side or a bulge protruding in a cut-off valve arrangement part is provided at an upper portion of the fuel tank. tank.

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