JP2001130269A - Fuel tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress evaporation of a fuel, and to easily ensure the strength of a tank shell and the reliability of a control valve. SOLUTION: A fuel tank body 10 is of a two-layer tank structure comprising an inner tank shell 26 and an outer tank shell 28, and a space 30 between tank shells is formed between the inner tank shell 26 and the outer tank shell 28 adjacent to each other. A pressure control valve 38 is disposed on an upper wall part of the inner tank shell 26. The space 30 between tank shells is communicated with a canister 34 via a pipe 44, and a pressure control valve 46 is disposed in the middle of the pipe 44. The pressure control valve 38 and the pressure control valve 46 are of mechanical type, and the internal pressure in the inner tank shell 26, i.e., the internal pressure P1 in the tank and the internal pressure P2 in the space 30 between tank shells are closer to the atmospheric pressure in this order.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a fuel tank,
In particular, it relates to a fuel tank mounted on a vehicle such as an automobile.

[0002]

2. Description of the Related Art Conventionally, in a fuel tank mounted on a vehicle such as an automobile, there is a fuel tank in which fuel evaporative gas (vapor) generated in the fuel tank is adsorbed to a canister. No., published in Japanese Unexamined Patent Publication No.

As shown in FIG. 4, in this fuel tank, a low pressure tank 82 having a fuel supply pipe 80 is connected to a high pressure tank 86 via a passage 84. The low pressure tank 82 stores the fuel at a low pressure near the outside air pressure, and the high pressure tank 86 stores the fuel at a pressure higher than a predetermined high pressure value. A pressure pump 88 is provided in the middle of the passage 84, and the high-pressure tank 86 is connected to an injector 92 of the internal combustion engine via a pressure regulator 90. The fuel is supplied to the low-pressure tank 82 through the fuel supply pipe 80, and the fuel in the low-pressure tank 82 is pressurized by the pressurizing pump 88 and sent to the high-pressure tank 86. That is, by storing the fuel in the high-pressure tank 86, the generation of fuel vapor is suppressed.

[0004]

However, in such a fuel tank, it is necessary to store the fuel in the high-pressure tank 86 at a pressure higher than a predetermined high-pressure value. As a result, since the high-pressure tank 86 needs to have a tank strength that can withstand the internal pressure, it is necessary to use a thick material or a highly rigid material for the tank shell of the tank. Further, in the control valve provided in the high-pressure tank 86, a high-performance control valve capable of holding a high pressure is required. Therefore, in such a fuel tank, a new material and control valve are used instead of the conventionally used material and control valve, and it is difficult to ensure the strength of the tank shell and the reliability of the control valve.

In view of the above, an object of the present invention is to provide a fuel tank which can suppress the generation of fuel vapor and can easily secure the strength of the tank shell and the reliability of the control valve.

[0006]

According to the first aspect of the present invention, there is provided a fuel tank body having a multi-layered tank shell structure in which tank shells are stacked at predetermined intervals, and formed between a tank internal pressure and an adjacent tank shell. The internal pressure of the inter-tank shell space is gradually approached to the outside pressure from the inside to the outside of the fuel tank body.

[0007] Therefore, by forming the fuel tank body into a multi-layer tank shell structure, it is possible to disperse the high-pressure tank internal pressure capable of suppressing the generation of evaporative fuel into the tank internal pressure and the internal pressure of a plurality of spaces between the tank shells. it can. As a result, the pressure difference between the inside and outside of each tank shell can be reduced. For this reason, a conventionally used material can be used for each tank shell, and a conventionally used control valve can also be used for the control valve disposed in each tank shell.
Therefore, the generation of fuel vapor can be suppressed, and the strength of the tank shell and the reliability of the control valve can be easily secured.

According to a second aspect of the present invention, in the fuel tank according to the first aspect, a pressure control valve is provided on the tank shell.

Therefore, in addition to the contents described in the first aspect, by controlling the internal pressure of the tank and the internal pressure of the space between the tank shells by the respective pressure control valves, the pressure difference between the inside and the outside of each tank shell can be adjusted.

According to a third aspect of the present invention, in the fuel tank according to the second aspect, a pressure sensor for detecting an internal pressure of the tank and an internal pressure of the space between the adjacent tank shells is provided, and based on a detection value of the pressure sensor. The pressure control valve is controlled.

Accordingly, in addition to the contents described in claim 2, it is possible to control the opening and closing of each pressure control valve based on the detection value of the pressure sensor for detecting the internal pressure of the tank and the internal pressure of the space between adjacent tank shells. For this reason, the tank internal pressure and the internal pressure in the space between the tank shells can be accurately controlled.

According to a fourth aspect of the present invention, in the fuel tank according to the second aspect, the space between the tank shells, which is the outermost one of the tank shell spaces, is communicated with a canister.

Therefore, in addition to the contents described in the second aspect, the gas discharged from the space between the tank shells, which is the outermost tank in the space between the tank shells, is guided to the canister, so that the fuel vapor is discharged into the atmosphere. Can be effectively prevented.

According to a fifth aspect of the present invention, there is provided the fuel tank according to the second aspect, wherein a cut-off valve is provided in the pressure control valve disposed in the tank shell which is the innermost one of the tank shells. Features.

Therefore, in addition to the contents of the second aspect, when the fuel level in the tank fluctuates, the fuel is supplied from the pressure control valve disposed in the tank shell located inside the tank by the cut-off valve. Leakage can be prevented.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a fuel tank according to the present invention will be described with reference to FIGS.

As shown in FIG. 1, in this embodiment, one end of an inlet pipe (fuel filling pipe) 12 penetrates the side wall of the fuel tank body 10, and the end of the inlet pipe 12 is It is inserted into the tank body 10. The other end of the inlet pipe 12 reaches a fuel supply port 14 provided in a side wall of the vehicle.

The oil supply port 14 has an oil supply cap 16.
At the time of refueling, by opening the fuel lid 18 and removing the refueling cap 16, a refueling gun (not shown) can be inserted. During refueling, when the fuel level in the inlet pipe 12 rises and a sensor provided on the refueling gun detects a full state, refueling from the refueling gun is automatically stopped. The fuel lid 18 has a fuel lid 18.
An open / close detection switch 20 for detecting the open / close of the switch is provided, and the open / close detection switch 20 is connected to a control circuit 22. Note that a ventilation pipe 24 is provided in the inlet pipe 12.

The fuel tank body 10 of the present embodiment is
Has a two-layer tank structure of an inner tank shell 26 and an outer tank shell 28, and a space 30 between tank shells is formed between adjacent inner tank shells 26 and outer tank shells 28. Inner tank shell 26 in fuel tank body 10
A well-known rollover valve 32 for ORVR (rollover) is disposed on an upper wall portion of the fuel cell, and a refueling vapor line 36 reaching a canister 34 is connected to the rollover valve 32.

A pressure control valve 38 is provided on the upper wall of the inner tank shell 26. In addition, since the space between the tank shells, which is the outermost tank, is two layers in this embodiment, the space 30 between the tank shells is connected to the canister 34 by a pipe 44, and a pressure control valve 46 is provided in the middle of the pipe 44. Are arranged. Each of the pressure control valve 38 and the pressure control valve 46 is of a mechanical type, and approaches the outside pressure in the order of the internal pressure in the inner tank shell 26, that is, the tank internal pressure P1, and the internal pressure P2 of the tank shell space 30. It has become.

Specifically, the opening pressure of the discharge valve of the pressure control valve 38 is set to ΔPp1, the opening pressure of the suction valve is set to ΔPv1, and the opening pressure of the discharge valve of the pressure control valve 46 is set to ΔPp2.
The valve opening pressure of the suction valve is set to ΔPv2. As a result, as shown in FIG. 2A, when the tank internal pressure P1 is a positive pressure, for example, assuming that the tank internal pressure P1, the internal pressure P2 of the tank shell space 30 and the external pressure are P0, the heat of the pump, etc. When the fuel in the tank (the inner tank shell 26) evaporates due to the above factor and the tank internal pressure P1 increases, the tank internal pressure P1 becomes ΔPp with respect to the internal pressure P2 of the space 30 between the tank shells.
Until the pressure becomes 1, the pressure control valve 38 is closed, trapping the pressure in the tank. On the other hand, when the tank internal pressure P1 exceeds ΔPp1 with respect to the internal pressure P2 of the inter-tank space 30, the pressure control valve 38 opens and gas in the tank flows into the inter-tank space 30. As a result, the internal pressure P2 of the space 30 between the tank shells rises, and the internal pressure P1 of the space 30
Is smaller than the internal pressure P2, and this pressure difference is ΔP
When the pressure falls below p1, the pressure control valve 38 closes again, and when the pressure difference exceeds ΔPp1 again, the pressure control valve 38 opens. For this reason, the tank internal pressure P1 and the internal pressure P2 of the tank shell space 30 gradually increase, and the internal pressure P2 of the tank shell space 30 becomes ΔPp2 with respect to the outside air pressure P0. ΔPp1 with respect to the internal pressure P2, ie, ΔPp1 + ΔPp2 with respect to the external pressure P0.
Is opened, and the gas in the space 30 between the tank shells is released from the canister 34.
It is designed to flow into.

On the other hand, as shown in FIG. 2B, when the tank internal pressure P1 becomes a negative pressure, for example, the tank internal pressure P1
1. Assuming that the internal pressure P2 and the external pressure of the tank shell space 30 are P0, the tank internal pressure P
As 1 decreases, the pressure control valve 38 is closed until the tank internal pressure P1 becomes ΔPv1 on the negative pressure side with respect to the internal pressure P2 of the tank shell space 30. On the other hand, the tank pressure P
1 is Δ on the negative pressure side with respect to the internal pressure P2 of the space 30 between tank shells.
When the pressure exceeds Pv1, the pressure control valve 38 opens and the gas in the space 30 between the tank shells flows into the tank. As a result, the internal pressure P2 of the inter-tank space 30 decreases, and the tank internal pressure P1
The pressure difference between the pressure and the internal pressure P2 of the space 30 between the tank shells becomes smaller. When this pressure difference becomes less than ΔPv1 on the negative pressure side, the pressure control valve 38 is closed again. Opens. Therefore, the tank internal pressure P1 and the internal pressure P2 of the space 30 between the tank shells gradually decrease, and the internal pressure P2 of the space 30 between the tank shells becomes ΔPv2 on the negative pressure side with respect to the external pressure P0, and the tank internal pressure P1 becomes The pressure becomes ΔPv1 on the negative pressure side with respect to the internal pressure P2 of the interspace 30, ie, ΔPv1 + ΔPv2 on the negative pressure side with respect to the external pressure P0.
6 is opened, and gas flows from the canister 34 into the space 30 between the tank shells.

A cut-off valve 40 is provided inside the tank of the pressure control valve 38 to prevent fuel from leaking from the pressure control valve 38 into the space 30 between the tank shells. An electromagnetic valve 48 is provided at an intermediate portion of the refueling vapor line 36. The solenoid valve 48 is connected to the control circuit 2
2 for refueling, ie, the open / close detection switch 2
When the open state of the fuel lid 18 is detected by 0, the valve is opened. The canister 34 is connected to a duct 54 communicating with the air cleaner 52 by a purge line 50.
A D-VSV (duty, vacuum switching valve) 56 is disposed at an intermediate portion of 0. On the other hand, the canister 34 is communicated with the air cleaner 52 via an intake pipe 58, and an intermediate portion of the intake pipe 58 has a closed VSV.
60 are provided. Further, the canister 34 is provided with an atmosphere valve 62.

A sub-tank 64 is disposed inside the inner tank shell 26. A pump unit 66 is disposed inside the sub-tank 64, and the pump unit 66 has a fuel supply pipe to the engine. 68 are connected.

Next, the operation of the present embodiment will be described.

The fuel tank body 10 of the present embodiment has a two-layer tank structure including an inner tank shell 26 and an outer tank shell 28, and includes a pressure control valve 38 and a pressure control valve 46 as shown in FIG. As shown in FIG. 2 (B), the tank internal pressure P1 and the internal pressure P2 of the tank shell space 30 approach the external pressure in this order. Therefore, in the conventional fuel tank, one tank shell and one pressure control valve are provided with the positive pressure ΔPp
1 + ΔPp2 and the negative pressure ΔPv1 + ΔPv2 had to be satisfied.
At 0, the positive pressure ΔPp1 and the negative pressure ΔPv1
, The outer tank shell 28 has a positive pressure ΔPp2,
What is necessary is just to have the pressure resistance of negative pressure (DELTA) Pv2.

For this reason, conventionally used materials can be used for the inner tank shell 26 and the outer tank shell 28, and the inner tank shell 26 and the outer tank shell 2 can be used.
As for the pressure control valves 38 and 46 disposed at 8, the pressure control valves conventionally used can be used.
Therefore, the generation of fuel vapor can be suppressed, and the strength of the tank shell and the reliability of the pressure control valve can be easily secured.

Further, in the present embodiment, the inter-tank space 30 is communicated with the canister 34 by the refueling vapor line 36, and the gas discharged from the inter-tank space 30 is guided to the canister 34, so that the gas is discharged into the atmosphere. Can be effectively prevented from being discharged.

In this embodiment, since the cutoff valve 40 is provided inside the tank of the pressure control valve 38, the fuel is supplied from the pressure control valve 38 to the space 3 between the tank shells.
It can be prevented from leaking into zero.

In this embodiment, the pressure control valve 38 is provided on the upper wall of the inner tank shell 26.
The arrangement position of 8 may be another part such as the upper part of the side wall of the inner tank shell 26. Further, the pressure control valve 46 is disposed in the middle of the pipe 44, but the pressure control valve 46 is
May be arranged at another portion such as the upper wall portion.

Next, a second embodiment of the fuel tank according to the present invention will be described with reference to FIG.

The same members as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 3, in this embodiment, the pressure control valve 38 and the pressure control valve 46 are each constituted by an electromagnetic valve, and the pressure control valve 38 and the pressure control valve 46 are respectively connected to the control circuit 22. It is connected to the. Also,
A pressure sensor 70 is provided on the upper wall of the inner tank shell 26, and a pressure sensor 72 is provided on the upper wall of the outer tank shell 28. The pressure sensor 70 can detect both the tank internal pressure P1 and the internal pressure P2 of the space 30 between the tank shells, and the pressure sensor 72 detects both the internal pressure P2 of the space 30 between the tank shells and the outside air pressure. It can be detected. The pressure sensor 7
0 and the pressure sensor 72 are respectively connected to the control circuit 22, and the control circuit 22 controls opening and closing of the pressure control valve 38 based on the detection value of the pressure sensor 70, and based on the detection value of the pressure sensor 72. The opening and closing of the pressure control valve 46 is controlled.

Specifically, when the pressure sensor 70 detects that the pressure difference between the tank internal pressure P1 and the internal pressure P2 of the space 30 between the tank shells is greater than ΔPp1 on the positive pressure side and greater than ΔPv1 on the negative pressure side, The pressure control valve 38 is opened by the output signal from the control circuit 22, and the internal pressure P2
When the pressure sensor 72 detects that the pressure difference between the pressure and the outside air pressure becomes ΔPp2 or more on the positive pressure side and ΔPv2 or more on the negative pressure side, the pressure control valve 4
6 is opened.

Next, the operation of the present embodiment will be described.

The fuel tank body 10 of the present embodiment has a two-layer tank structure of an inner tank shell 26 and an outer tank shell 28, and the pressure difference between the tank internal pressure P1 and the internal pressure P2 of the space 30 between the tank shells is determined. If the pressure sensor 70 detects ΔPp1 or more on the positive pressure side and ΔPv1 or more on the negative pressure side, the pressure control valve 3
8 is opened, and when the pressure sensor 72 detects that the pressure difference between the internal pressure P2 of the tank shell space 30 and the outside air pressure becomes ΔPp2 or more on the positive pressure side and ΔPv2 or more on the negative pressure side, the control circuit 22 The output signal opens the pressure control valve 46.

As a result, in this embodiment, as in the first embodiment, the tank internal pressure P1 and the
The internal pressure P2 approaches the external pressure in this order. Therefore, in the conventional fuel tank, one tank shell and one pressure control valve are provided with the positive pressure ΔPp1 + ΔPp2 and the negative pressure ΔPv1.
Although it was necessary to satisfy the performance of maintaining + ΔPv2, in the fuel tank 10 of the present embodiment, the inner tank shell 26 has a pressure resistance of the positive pressure ΔPp1 and the negative pressure ΔPv1 and the outer tank shell 28 has a positive pressure ΔPp2 and the negative pressure ΔPp2. What is necessary is just to have the pressure resistance of pressure (DELTA) Pv2.

For this reason, conventionally used materials can be used for the inner tank shell 26 and the outer tank shell 28, and the inner tank shell 26 and the outer tank shell 2 can be used.
As for the pressure control valves 38 and 46 disposed at 8, the pressure control valves conventionally used can be used.
Therefore, the generation of fuel vapor can be suppressed, and the strength of the tank shell and the reliability of the pressure control valve can be easily secured.

In this embodiment, the pressure sensor 70 for detecting the tank internal pressure P1 and the internal pressure P2 of the inter-tank space 30 and the pressure sensor 72 for detecting the internal pressure P2 and the external pressure of the inter-tank space 30 are provided. Provided, pressure sensors 70, 72
It is possible to control the pressure control valves 38 and 46 by the control circuit 22 on the basis of the respective detected values of the above, so that the tank internal pressure P1 and the internal pressure P2 of the tank shell space 30 can be accurately controlled. it can.

Also in this embodiment, as in the first embodiment, the tank space 30 is communicated with the canister 34 by the refueling vapor line 36, and the gas discharged from the tank space 30 is discharged from the canister 34. Therefore, discharge of fuel vapor into the atmosphere can be effectively prevented.

Also in this embodiment, as in the first embodiment, a cutoff valve 40 is provided inside the tank of the pressure control valve 38, so that the pressure control valve 38
The fuel can be prevented from leaking into the space 30 between the tank shells.

In this embodiment, the inner tank shell 26
A pressure sensor 70 is disposed on the upper wall of the outer tank shell 28.
The pressure sensor 72 is disposed on the upper wall of the
The arrangement positions of 0 and 72 are not limited to the positions in the present embodiment, and may be other positions. Further, a configuration may be adopted in which the tank internal pressure P1, the internal pressure P2 of the tank shell space 30, and the external pressure are detected by different independent pressure sensors.

In the above, the present invention has been described in detail with respect to a specific embodiment. However, the present invention is not limited to such an embodiment, and various other embodiments are within the scope of the present invention. It is clear to a person skilled in the art that is possible. For example, in each of the above embodiments, the fuel tank body 1
Although 0 is a two-layer tank structure of the inner tank shell 26 and the outer tank shell 28, the fuel tank body 10 may be configured to have three or more tank shells instead.

[0044]

According to the first aspect of the present invention, there is provided a fuel tank.
A fuel tank body having a multi-layer tank shell structure in which tank shells are stacked at predetermined intervals, wherein the internal pressure of the tank and the internal pressure of the space between the tank shells formed between adjacent tank shells are directed from the inside to the outside of the fuel tank body. In this case, since the temperature of the tank is gradually brought close to the outside air pressure, the generation of fuel vapor can be suppressed, and the strength of the tank shell and the reliability of the control valve can be easily secured.

According to a second aspect of the present invention, in the fuel tank according to the first aspect, a pressure control valve is provided on the tank shell, so that in addition to the effect of the first aspect, the pressure difference between the inside and outside of each tank shell is adjusted. It has an excellent effect that it becomes possible.

According to a third aspect of the present invention, in the fuel tank according to the second aspect, a pressure sensor for detecting the internal pressure of the tank and the internal pressure of the space between adjacent tank shells is provided, and the pressure is determined based on a detection value of the pressure sensor. Since the control valve is controlled, there is an excellent effect that the tank internal pressure and the internal pressure of the space between the shells can be accurately controlled in addition to the effect described in claim 2.

According to a fourth aspect of the present invention, in the fuel tank according to the second aspect, the space between the outermost shells among the inter-shell spaces is communicated with the canister. It has an excellent effect that the emission of fuel vapor into the atmosphere can be effectively prevented.

According to a fifth aspect of the present invention, in the fuel tank according to the second aspect, a cutoff valve is provided in the pressure control valve disposed in the tank shell which is the innermost of the tank shells. In addition to the effects described above, there is an excellent effect that fuel can be prevented from leaking from the pressure control valve disposed in the tank shell that is the innermost of the tank.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view showing a fuel tank according to a first embodiment of the present invention.

FIG. 2A is a graph showing a pressure change at a positive pressure in a fuel tank according to the first embodiment of the present invention,
(B) is a graph showing a pressure change at the time of negative pressure in the fuel tank according to the first embodiment of the present invention.

FIG. 3 is a schematic side sectional view showing a fuel tank according to a second embodiment of the present invention.

FIG. 4 is a schematic side sectional view showing a conventional fuel tank.

[Explanation of symbols]

 Reference Signs List 10 fuel tank main body 22 control circuit 26 inner tank shell 28 outer tank shell 30 space between tank shells 34 canister 38 pressure control valve 40 cutoff valve 46 pressure control valve 70 pressure sensor 72 pressure sensor

Claims (5)

[Claims] 1. A fuel tank main body having a multi-layered tank shell structure in which tank shells are stacked at predetermined intervals, wherein the internal pressure of the tank and the internal pressure of a space between tank shells formed between adjacent tank shells are controlled by the fuel tank main body. A fuel tank characterized by sequentially approaching the outside air pressure from the inside to the outside. 2. The fuel tank according to claim 1, wherein a pressure control valve is provided on the tank shell. 3. A pressure sensor for detecting an internal pressure of a tank and an internal pressure of a space between adjacent tank shells, and controlling the pressure control valve based on a detection value of the pressure sensor. Fuel tank. 4. The fuel tank according to claim 2, wherein a space between the tank shells, which is the outermost tank among the space between the tank shells, communicates with a canister. 5. The fuel tank according to claim 2, wherein a cut-off valve is provided in the pressure control valve disposed in the tank shell that is the innermost one of the tank shells.