Fuel tank system for vehicle

Abstract

To provide a fuel tank system to which a fuel pipe is easily attached.SOLUTION: The fuel-tank system includes a first main shut-off valve 4a connected to the first fuel-tank 5a, a second main shut-off valve 4b connected to the second fuel-tank 5b, and a second fuel-supply pipe 5a having one end connected to the first fuel-tank 4a via the first main shut-off valve 5b and the other end connected to the second fuel-tank 4b via the second main shut-off valve 6b. The second fuel supply pipe 6b is connected to the first and second main stop valves 5a and 5b from the same side in the vehicle-width direction. The pair of fuel tanks 4 are arranged such that the first main stop valves 5a and the second main stop valves 5b are located on the same side in the vehicle front-rear direction, and the first main stop valves 5a and the second main stop valves 5b are located at different height positions in the vehicle up-down direction.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a fuel tank system for a vehicle. [Background technology]

[0002] For example, Patent Document 1 discloses a configuration in which hydrogen tanks as fuel tanks are arranged along the longitudinal direction of the vehicle at both ends of the vehicle width direction of the cabin floor of an automobile body.

[0003] In Patent Document 1, left and right hydrogen tanks are individually connected by respective pipelines to an FC stack (fuel cell stack) located in the center in the vehicle width direction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-26117 Summary of the Invention [Problem to be solved by the invention]

[0005] However, Patent Document 1 merely discloses a pipeline that simply connects a hydrogen tank and an FC stack, and does not give any consideration to the ease of attaching (connecting) the pipeline to the hydrogen tank.

[0006] That is, in a system that supplies fuel from a fuel tank to a fuel cell via a fuel pipe such as a pipeline, there is room for further improvement in terms of the ease of attaching (connecting) the fuel pipe to other components within the system. [Means for solving the problem]

[0007] A vehicle fuel tank system of the present invention includes a pair of fuel tanks arranged side by side in the vehicle width direction, a first main stop valve connected to one of the pair of fuel tanks located on one side in the vehicle width direction, a second main stop valve connected to the other of the pair of fuel tanks located on the other side in the vehicle width direction, and a fuel pipe having one end connected to the one fuel tank via the first main stop valve and the other end connected to the other fuel tank via the second main stop valve. The fuel pipe is connected to the one main stop valve and the second main stop valve from the same direction in the vehicle width direction. The pair of fuel tanks are arranged so that the one main stop valve and the second main stop valve are located on the same side in the vehicle fore-and-aft direction and so that the one main stop valve and the second main stop valve are at different heights in the vehicle up-and-down direction. [Effects of the Invention]

[0008] In the vehicle fuel tank system of the present invention, the movement of the fuel pipe along the vehicle width direction when connecting the fuel pipe to the main stop valve is less likely to be restricted by the main stop valve and the components around the main stop valve, compared to when the main stop valves of a pair of adjacent fuel tanks are at the same height position along the fore-and-aft direction of the vehicle, thereby improving the ease of attaching (connecting) the fuel pipe to the main stop valve. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an explanatory diagram showing a schematic outline of a fuel tank system for a vehicle according to the present invention; [Figure 2] 1 is an explanatory diagram showing an enlarged view of a fuel tank system of a vehicle according to the present invention; [Figure 3] FIG. 2 is an explanatory diagram illustrating a schematic arrangement of a fuel tank relative to a vehicle. [Figure 4] FIG. 2 is an explanatory diagram illustrating a schematic arrangement of a fuel tank relative to a vehicle. [Figure 5] FIG. 2 is an enlarged explanatory diagram showing a fuel supply pipe of the fuel tank system. [Figure 6]FIG. 4 is an explanatory diagram schematically showing the positional relationship between a first main stop valve, a second main stop valve, and a second fuel supply pipe. [Figure 7] FIG. 4 is an explanatory diagram schematically showing the positional relationship between a first main stop valve, a second main stop valve, and a second fuel supply pipe. [Figure 8] FIG. 4 is an explanatory diagram schematically showing the positional relationship between a first main stop valve, a second main stop valve, and a second fuel supply pipe. [Figure 9] FIG. 10 is an explanatory diagram schematically showing the positional relationship between a first main stop valve, a second main stop valve, and a fuel supply pipe in a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the present invention will be described in detail below with reference to the drawings.

[0011] Fig. 1 is an explanatory diagram that shows a schematic overview of a fuel tank system 2 of a vehicle 1 according to the present invention. Fig. 2 is an explanatory diagram that shows an enlarged view of the fuel tank system 2. Figs. 3 and 4 are explanatory diagrams that show a schematic arrangement of a fuel tank 4 relative to the vehicle 1, with Fig. 3 being an explanatory diagram of the vehicle 1 as viewed from the front (front), and Fig. 4 being an explanatory diagram of the vehicle 1 as viewed from the side (side).

[0012] The fuel tank system 2 supplies fuel to a fuel cell 3 mounted on a vehicle 1, and includes a plurality of cylindrical fuel tanks 4, a plurality of main stop valves 5 individually connected to each fuel tank 4, a fuel supply pipe 6 connected to the fuel tanks 4 via the main stop valves 5, a pressure reducing valve 7 that reduces the pressure of the fuel supplied to the fuel cell 3, a desulfurizer 8 that removes sulfur from the fuel that has been pressure reduced by the pressure reducing valve 7, and a subframe 9 for the fuel tanks 4 that surrounds the plurality of fuel tanks 4.

[0013] The fuel cell 3 uses the supplied fuel to generate electric power that is supplied to a drive motor and the like that drives the vehicle 1. The electric power generated by the fuel cell 3 is charged into a battery 11 via a voltage conversion device 10.

[0014] The vehicle 1 uses the electric power generated by the battery 11 or the fuel cell 3 to drive a traction motor (not shown), which drives the drive wheels of the vehicle 1 (for example, the left and right front wheels 12 in FIG. 1).

[0015] The fuel tank 4 is filled with high-pressure fuel gas, such as natural gas, as the fuel to be supplied to the fuel cell 3.

[0016] The fuel tank 4 is a so-called pressure tank (pressure vessel) that is roughly composed of a cylindrical central portion 21 and one end portion 22 and the other end portion 23 formed by hemispherical end plates that close the ends of the central portion 21, and is capable of storing high-pressure fuel.

[0017] The fuel tank 4 is disposed such that one end 22, of both axial ends to which the main stop valve 5 is connected, is located rearward in the vehicle longitudinal direction. The other end 23 of the fuel tank 4 is located forward in the vehicle longitudinal direction. The one end 22 and the other end 23 of the fuel tank 4 are each supported or fixed to, for example, the subframe 9 via brackets 24.

[0018] In this embodiment, the multiple fuel tanks 4 include two fuel tanks: a first high-pressure fuel tank 4a disposed at approximately the center of the vehicle 1 in the width direction, and a second high-pressure fuel tank 4b adjacent to the first fuel tank 4a. In other words, the multiple fuel tanks 4 are a pair of fuel tanks 4 consisting of the first fuel tank 4a and the second fuel tank 4b. The second fuel tank 4b is a fuel tank having a smaller diameter than the first fuel tank 4a. In other words, the central portion 21b of the second fuel tank 4b has a smaller diameter than the central portion 21a of the first fuel tank 4a. The one end 22b and the other end 23b of the second fuel tank 4b have smaller diameters than the one end 22a and the other end 23a of the first fuel tank 4a.

[0019] The first fuel tank 4a and the second fuel tank 4b are disposed under the floor of the vehicle 1 in a direction along the front-to-rear direction of the vehicle 1 (the up-and-down direction in FIG. 1), and are also disposed side by side (parallel) in the width direction of the vehicle 1. The first fuel tank 4a corresponds to the other fuel tank of the pair of fuel tanks 4 that is located on the other side in the vehicle width direction. The second fuel tank 4b corresponds to the one fuel tank of the pair of fuel tanks 4 that is located on one side in the vehicle width direction.

[0020] As shown in Figures 3 and 4, the first fuel tank 4a and the second fuel tank 4b are arranged horizontally and parallel to each other. Furthermore, as shown in Figures 3 and 4, the first fuel tank 4a and the second fuel tank 4b are arranged so that their respective tank central axes are at different height positions in the vertical direction of the vehicle. The tank central axis is the central axis of the fuel tank 4 that is aligned along the longitudinal direction of the fuel tank 4. Note that the symbol P in Figure 3 indicates a floor panel arranged on the floor of the vehicle 1.

[0021] In this embodiment, the first fuel tank 4a is connected in series to the second fuel tank 4b via a fuel supply pipe 6. In this embodiment, the first fuel tank 4a is located downstream of the second fuel tank 4b in the direction of fuel flow toward the fuel cell 3. Fuel is filled into the fuel tank 4 from a fill port 13 provided on the side (left side) of the vehicle 1 via a first fuel supply pipe 6a (details of which will be described later).

[0022] The main stop valve 5 has the function of opening and closing the fuel tank 4, and enables filling of the fuel tank 4 with fuel and supply (discharge) of fuel from the fuel tank 4 to the fuel cell 3. The main stop valve 5 also has a first connection port 25 and a second connection port 26 to which a fuel supply pipe 6 can be connected. The first and second connection ports 25, 26 are so-called joint attachment portions, and the pipes are attached using threaded joints. In this embodiment, the first connection port 25 is located 180 degrees opposite the second connection port 26 with respect to the central axis of the main stop valve 5, which is aligned with the axial direction of the fuel tank 4. The main stop valve 5 has a communication passage (not shown) therein that connects the first connection port 25 and the second connection port 26.

[0023] The main stop valves 5 in this embodiment are a first main stop valve 5a as the other-side main stop valve attached to the first fuel tank 4a, and a second main stop valve 5b as the one-side main stop valve attached to the second fuel tank 4b.

[0024] The fuel supply pipe 6 is one through which fuel can pass, and includes a first fuel supply pipe 6a connecting the filling port 13 and the second main stop valve 5b, a second fuel supply pipe 6b connecting the second main stop valve 5b and the first main stop valve 5a, a third fuel supply pipe 6c connecting the first main stop valve 5a and the pressure reducing valve 7, a fourth fuel supply pipe 6d connecting the pressure reducing valve 7 and the desulfurizer 8, and a fifth fuel supply pipe 6e connecting the desulfurizer 8 and the fuel cell 3.

[0025] One end of the first fuel supply pipe 6a is connected to the first connection port 25b of the second main stop valve 5b, and the other end is connected to the filling port 13. In other words, one end of the first fuel supply pipe 6a is attached and fixed to the first connection port 25b of the second main stop valve 5b, and the other end is attached and fixed to the filling port 13. The first fuel supply pipe 6a is a high-pressure pipe that is located upstream of the pressure reducing valve 7 in the fuel flow direction toward the fuel cell 3, and through which high-pressure fuel that is not reduced in pressure by the pressure reducing valve 7 flows.

[0026] One end of the second fuel supply pipe 6b is connected to the second connection port 26a of the first main stop valve 5a, and the other end is connected to the second connection port 26b of the second main stop valve 5b. In other words, one end of the second fuel supply pipe 6b is attached and fixed to the second connection port 26a of the first main stop valve 5a, and the other end is attached and fixed to the second connection port 26b of the second main stop valve 5b.

[0027] The second fuel supply pipe 6b corresponds to a fuel pipe and has one end connected to the first fuel tank 4a via the first main stop valve 5a and the other end connected to the second fuel tank 4b via the second main stop valve 5b. In other words, the second fuel supply pipe 6b has one end connected to the second connection port 26a of the first main stop valve 5a, which is a one-end connection port, and the other end connected to the second connection port 26b of the second main stop valve 5b, which is a other-end connection port.

[0028] The second fuel supply pipe 6b is a high-pressure pipe located upstream of the pressure reducing valve 7 in the fuel flow direction toward the fuel cell 3, through which high-pressure fuel that is not reduced in pressure by the pressure reducing valve 7 flows.

[0029] One end of the third fuel supply pipe 6c is connected to the pressure reducing valve 7, and the other end is connected to the first connection port 25a of the first main stop valve 5a. In other words, one end of the third fuel supply pipe 6c is attached and fixed to the pressure reducing valve 7, and the other end is attached and fixed to the first connection port 25a of the first main stop valve 5a. The third fuel supply pipe 6c is a high-pressure pipe that is located upstream of the pressure reducing valve 7 in the fuel flow direction toward the fuel cell 3, and through which high-pressure fuel that is not reduced in pressure by the pressure reducing valve 7 flows.

[0030] One end of the fourth fuel supply pipe 6d is connected to the desulfurizer 8, and the other end is connected to the pressure reducing valve 7. In other words, one end of the fourth fuel supply pipe 6d is attached and fixed to the desulfurizer 8, and the other end is attached and fixed to the pressure reducing valve 7. The fourth fuel supply pipe 6d is a low-pressure pipe that is located downstream of the pressure reducing valve 7 in the fuel flow direction toward the fuel cell 3, and through which low-pressure fuel reduced in pressure by the pressure reducing valve 7 flows.

[0031] The fifth fuel supply pipe 6e has one end connected to the fuel cell 3 and the other end connected to the desulfurizer 8. In other words, the fifth fuel supply pipe 6e has one end attached and fixed to the fuel cell 3 and the other end attached and fixed to the desulfurizer 8. The fifth fuel supply pipe 6e is a low-pressure pipe located downstream of the desulfurizer 8 in the fuel flow direction toward the fuel cell 3, and through which low-pressure fuel reduced in pressure by the pressure reducing valve 7 flows.

[0032] The pressure reducing valve 7 reduces (adjusts) the pressure of the fuel from the fuel tank 4 to a predetermined pressure and supplies it to the downstream side (fuel cell side), and is located downstream of the fuel tank 4 and upstream of the desulfurizer 8 in the fuel flow direction toward the fuel cell 3.

[0033] The desulfurizer 8 is disposed adjacent to the first fuel tank 4a on the opposite side of the second fuel tank 4b with the first fuel tank 4a in between. The desulfurizer 8 is located downstream of the pressure reducing valve 7 and upstream of the fuel cell 3 in the fuel flow direction toward the fuel cell 3. Note that the desulfurizer 8 can be omitted if the fuel supplied to the fuel cell 3 does not contain sulfur.

[0034] The subframe 9 is disposed at the center in the vehicle width direction between the pair of side frames 14a, 14b, and is one of the components of the body frame of the vehicle 1. Furthermore, the subframe 9 corresponds to a vehicle structural member of the vehicle 1.

[0035] Here, the side frames 14 are one of the components of the body frame, and are vehicle structural members located on both sides of the vehicle 1 and extending in the longitudinal direction of the vehicle 1. The left and right side frames 14a, 14b are connected by a plurality of cross members 15 extending in the vehicle width direction. The cross members 15 correspond to vehicle structural members. The pair of side frames 14a, 14b and the plurality of cross members 15 are connected to each other, forming an overall ladder shape.

[0036] The subframe 9 has a plurality of longitudinal members 31 that extend in an elongated manner along the longitudinal direction of the vehicle, a plurality of widthwise members 32 that extend in an elongated manner along the vehicle width direction, and a plurality of vertical members 33 that extend in an elongated manner along the vehicle up-down direction. By connecting the plurality of longitudinal members 31, the plurality of widthwise members 32, and the plurality of vertical members 33 to one another, the subframe 9 has an overall shape of a rectangular box without a lid that surrounds the periphery of the first and second fuel tanks 4a, 4b, the pressure reducing valve 7, and the desulfurizer 8.

[0037] The multiple longitudinal members 31 include at least a one-side longitudinal member 31a located between the second fuel tank 4b and the side frame 14a located on one side in the vehicle width direction when viewed from above the vehicle, and an other-side longitudinal member 31b located between the desulfurizer 8 and the side frame 14b located on the other side in the vehicle width direction.

[0038] The multiple width direction members 32 include at least a rear width direction member 32a positioned so as to face the main stop valve 5 in the vehicle longitudinal direction. Both ends of the multiple width direction members 32 are connected to one side longitudinal direction member 31a and the other side longitudinal direction member 31b on both sides, respectively.

[0039] The vertical members 33 are located at least at the four corners of the subframe 9, for example.

[0040] 5, the fuel supply pipe 6 of the fuel tank system 2 is fixed to a rear width direction member 32a extending along the width direction of the vehicle 1 via a clip member 16. FIG. 5 is an explanatory diagram showing an enlarged view of the fuel supply pipe 6 of the fuel tank system 2.

[0041] 5, the rear width direction member 32a is two rear width direction members 32aa and 32ab arranged side by side at different heights in the vertical direction of the vehicle 1. The rear width direction member 32aa is located higher than the rear width direction member 32ab in the vertical direction of the vehicle 1.

[0042] The rear width direction member 32aa is located higher than the first main stop valve 5a and the second main stop valve 5b in the vehicle vertical direction. The rear width direction member 32ab is located lower than the first main stop valve 5a and the second main stop valve 5b in the vehicle vertical direction.

[0043] The clip member 16 is made of, for example, a resin material, and is fixed to the fuel supply pipe 6 and is also fixed to the rear width direction member 32a.

[0044] The first fuel supply pipe 6a is fixed to the second main stop valve 5b and two rear width direction members 32aa, 32ab which are located at different height positions.

[0045] The second fuel supply pipe 6b is fixed to the first main stop valve 5a, the second main stop valve 5b, and the rear width direction member 32aa.

[0046] In this embodiment, the attachment position of the fuel supply pipe 6 relative to the first main stop valve 5a is located higher in the vehicle vertical direction than the attachment position of the fuel supply pipe 6 relative to the second main stop valve 5b. That is, the height positions of one end of the second fuel supply pipe 6b and the other end of the third fuel supply pipe 6c attached to the first main stop valve 5a in the vehicle vertical direction are located higher than the height positions of one end of the first fuel supply pipe 6a and the other end of the second fuel supply pipe 6b attached to the second main stop valve 5b in the vehicle vertical direction. In other words, the second connection port 26a to which one end of the second fuel supply pipe 6b is connected and the second connection port 26b to which the other end of the second fuel supply pipe 6b is connected are located at the same height position in the vehicle vertical direction. Furthermore, the first fuel tank 4a and the second fuel tank 4b are arranged so that the second connection port 26a of the first main stop valve 5a and the second connection port 26b of the second main stop valve 5b are located at the same position in the vehicle longitudinal direction.

[0047] As shown in Fig. 6, the second fuel supply pipe 6b in the fuel tank system 2 of this embodiment can be connected to the first main stop valve 5a and the second main stop valve 5b from the same direction in the vehicle width direction, that is, from the right side in the left-right direction in Fig. 6. Fig. 6 is an explanatory diagram that schematically shows the positional relationship between the first main stop valve 5a, the second main stop valve 5b, and the second fuel supply pipe 6b.

[0048] As shown in FIG. 6, the second fuel supply pipe 6b passes above the second main stop valve 5b in the vehicle up-down direction and is connected to the first main stop valve 5a from one side in the vehicle width direction.

[0049] 5 to 7, the second fuel supply pipe 6b has a plurality of bent portions 41 between one end connected to the first main stop valve 5a and the other end connected to the second main stop valve 5b. The bent portions 41 are bending points of the second fuel supply pipe 6b.

[0050] Fig. 7 is an explanatory diagram showing a schematic diagram of the positional relationship between the first main stop valve 5a, the second main stop valve 5b, and the second fuel supply pipe 6b, as viewed from above in the vehicle vertical direction. Fig. 8 is an explanatory diagram showing a schematic diagram of the positional relationship between the first main stop valve 5a, the second main stop valve 5b, and the second fuel supply pipe 6b, as viewed from the side in the vehicle width direction.

[0051] The plurality of bent portions 41 are, in order from one end side to the other end side of the second fuel supply pipe 6b, a first bent portion 41a, a second bent portion 41b, a third bent portion 41c, and a fourth bent portion 41d.

[0052] Here, the shape of the second fuel supply pipe 6b will be described in detail on a three-dimensional orthogonal coordinate system in which the axis along the vehicle longitudinal direction is the X-axis, the axis along the vehicle width is the Y-axis, and the axis along the vehicle vertical direction is the Z-axis.

[0053] The first bent portion 41a is a bent portion on the XY plane including the X-axis and the Y-axis, and is a portion where the second fuel supply pipe 6b extending from the first main stop valve 5a along the vehicle width direction is bent rearward in the vehicle front-rear direction. The first bent portion 41a is a two-dimensional bend on the XY plane.

[0054] The second bent portion 41b is a bent portion on the XY plane including the X-axis and the Y-axis, where the second fuel supply pipe 6b extending from the first bent portion 41a in the vehicle longitudinal direction is bent toward the second fuel tank 4b in the vehicle width direction. The second bent portion 41b is a two-dimensional bend on the XY plane.

[0055] The third bent portion 41c is a portion where the second fuel supply pipe 6b extending from the second bent portion 41b along the vehicle width direction is bent downward in the vehicle up-down direction and also bent forward in the vehicle front-rear direction. The third bent portion 41c is a three-dimensional bend that combines a two-dimensional bend on the XY plane and a two-dimensional bend on the YZ plane.

[0056] The fourth bent portion 41d is a portion where the second fuel supply pipe 6b, which extends obliquely from the second bent portion 41b in the vehicle longitudinal direction and the vehicle vertical direction, is bent in the vehicle width direction and bent so that its height position does not change in the vehicle vertical direction. The fourth bent portion 41d is a three-dimensional bend that combines two-dimensional bending on the XY plane and two-dimensional bending on the YZ plane.

[0057] The first fuel tank 4a and the second fuel tank 4b, which are a pair of fuel tanks 4, are arranged so that the first main stop valve 5a and the second main stop valve 5b are at different height positions in the vehicle vertical direction. The first fuel tank 4a and the second fuel tank 4b have different outer diameters, i.e., the outer diameters of the central portions 21, so when they are lined up based on their lower end positions in the vehicle vertical direction, the first main stop valve 5a and the second main stop valve 5b are at different height positions in the vehicle vertical direction.

[0058] The first main stop valve 5a and the second main stop valve 5b may be arranged to partially overlap each other in the vertical direction of the vehicle.

[0059] 9, if the first main stop valve 5a of the first fuel tank 4a and the second main stop valve 5b of the second fuel tank 4b are at the same height in the longitudinal direction of the vehicle, and if the fuel supply pipe 51 connecting the first fuel tank 4a and the second fuel tank 4b is to be connected to the first fuel tank 4a and the second fuel tank 4b from the same direction in the width direction of the vehicle, it will be necessary to provide multiple auxiliary bends 52 to remove (avoid) one of the main stop valves 5 (the second main stop valve 5b in the illustrated example). The fuel supply pipe 51 is the second fuel supply pipe 6b described above, with additional auxiliary bends 52 provided.

[0060] The comparative example shown in Fig. 9 is an explanatory diagram that schematically shows a case in which the first main stop valve 5a and the second main stop valve 5b are connected to the first main stop valve 5a and the second main stop valve 5b from the same direction in the vehicle width direction when the height positions of the first main stop valve 5a and the second main stop valve 5b in the vehicle up-down direction in the above-described embodiment. In the comparative example shown in Fig. 9, in order to connect the fuel supply pipe 51 to the first main stop valve 5a and the second main stop valve 5b from the same direction in the vehicle width direction, a first auxiliary bent portion 52a and a second auxiliary bent portion 52b are formed so that the second main stop valve 5b can be moved in the vehicle up-down direction.

[0061] If multiple auxiliary bends 52 are provided in the fuel supply pipe 51 as in the comparative example, movement along the vehicle width direction when connecting the fuel supply pipe 51 to the first main stop valve 5a and the second main stop valve 5b is likely to be restricted by the components surrounding the main stop valve 5, which may make it difficult to connect the fuel supply pipe 51 to the main stop valve 5.

[0062] In contrast, in the fuel tank system 2 of the embodiment described above, a pair of fuel tanks 4, the first fuel tank 4a connected to the first main stop valve 5a and the second fuel tank 4b connected to the second main stop valve 5b, are arranged side by side in the vehicle width direction. In the fuel tank system 2, the pair of fuel tanks 4 are arranged so that the first main stop valve 5a and the second main stop valve 5b are located on the same side in the vehicle front-to-rear direction, and the first main stop valve 5a and the second main stop valve 5b are at different height positions in the vehicle up-down direction.

[0063] Therefore, in the fuel tank system 2 of the above-described embodiment, compared to the comparative example in which the main stop valves 5 of a pair of adjacent fuel tanks 4 are at the same height position in the fore-and-aft direction of the vehicle, the movement of the second fuel supply pipe 6b along the vehicle width direction when connecting the second fuel supply pipe 6b to the main stop valve 5 is less likely to be restricted by the main stop valve 5 and the components surrounding the main stop valve 5, thereby improving the ease of attaching (connecting) the second fuel supply pipe 6b to the main stop valve 5.

[0064] Furthermore, in the fuel tank system 2, when connecting the second fuel supply pipe 6b to the main stop valve 5, the movement of the second fuel supply pipe 6b along the vehicle width direction is less restricted by the main stop valve 5 than when the main stop valves 5 of a pair of adjacent fuel tanks 4 are at the same height position along the vehicle fore-and-aft direction. This reduces the number of bends 41 (break points) required from one end to the other of the second fuel supply pipe 6b, and simplifies the overall shape of the second fuel supply pipe 6b from one end to the other.

[0065] Furthermore, in the fuel tank system 2, the first fuel tank 4a can be made larger in diameter than the second fuel tank 4b, which increases the variety of combinations of adjacent pairs of fuel tanks 4. For example, by combining fuel tanks 4 with the largest diameters appropriate for the installation position, the amount of fuel that can be carried can be increased efficiently.

[0066] Although specific embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention.

[0067] For example, as shown by the dashed line in Figure 6, the second fuel supply pipe 6b may pass below the first main stop valve 5a in the vehicle vertical direction and connect to the second main stop valve 5b from the other side in the vehicle width direction.

[0068] For example, the pair of fuel tanks 4, the first fuel tank 4a and the second fuel tank 4b, may be arranged so that the second connection port 26a of the first main stop valve 5a and the second connection port 26b of the second main stop valve 5b are at different positions in the fore-and-aft direction of the vehicle. [Explanation of symbols]

[0069] 1...Vehicle 2...Fuel tank system 3…Fuel cell 4. Fuel tank 4a...First fuel tank 4b...Second fuel tank 5…Main stop valve 5a...1st main stop valve 5b…Second main stop valve 6…Fuel supply piping 6b...Second fuel supply pipe 25...First connection port 25a...First connection port 25b...First connection port 26...Second connection port 26a...Second connection port 26b...Second connection port 41...Bend

Claims

1. a pair of fuel tanks arranged side by side in the vehicle width direction under the floor of the vehicle; a one-side main stop valve connected to one of the pair of fuel tanks located on one side in a vehicle width direction; a second main stop valve connected to the second fuel tank located on the other side of the pair of fuel tanks in the vehicle width direction; a fuel pipe having one end connected to the one-side fuel tank via the one-side main stop valve and the other end connected to the other-side fuel tank via the other-side main stop valve, the fuel pipe is connected to the one-side main stop valve and the other-side main stop valve from the same direction in the vehicle width direction, a pair of fuel tanks, the one-side main stop valve and the other-side main stop valve being located on the same side in the vehicle longitudinal direction, and the one-side main stop valve and the other-side main stop valve being located at different height positions in the vehicle vertical direction.

2. 2. The vehicle fuel tank system according to claim 1, wherein the one-side fuel tank and the other-side fuel tank have cylindrical shapes and different outer diameters, so that the one-side main stop valve and the other-side main stop valve are at different height positions in the vehicle up-down direction.

3. the pair of fuel tanks are arranged such that the other-side main stop valve is located higher than the one-side main stop valve in the vehicle vertical direction, 2. The vehicle fuel tank system according to claim 1, wherein the fuel pipe passes above the one-side main stop valve in the vertical direction of the vehicle and is connected to the other-side main stop valve.

4. the pair of fuel tanks are arranged such that the other-side main stop valve is located higher than the one-side main stop valve in the vehicle vertical direction, 2. The vehicle fuel tank system according to claim 1, wherein the fuel pipe passes below the other-side main stop valve in the vertical direction of the vehicle and is connected to the one-side main stop valve.

5. the one-side main stop valve and the other-side main stop valve have connection ports to which the fuel pipe can be connected, 2. The vehicle fuel tank system according to claim 1, wherein the pair of fuel tanks are arranged so that the connection port of the one main stop valve and the connection port of the other main stop valve are located at different positions in the fore-and-aft direction of the vehicle.

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