Fuel tank system for vehicle

Abstract

A fuel tank system (2) is provided with: a floor panel (P) arranged on a floor part of a vehicle; and a first fuel tank (4a) arranged below the floor panel (P) in a direction along a vehicle front-rear direction. The floor panel P has: a flat floor planar part (27); and a floor tunnel part (28) that protrudes upward in a vehicle vertical direction with respect to the floor planar part (27) and extends while inclining along the vehicle front-rear direction. The first fuel tank (4a) is arranged so as to be inclined within the floor tunnel part (28). The fuel tank system (2) can increase the capacity by increasing the total length of the first fuel tank (4a) that can be arranged in the floor tunnel part (28), and can generally increase the amount of fuel that can be loaded onto the vehicle.

Description

Vehicle fuel tank system

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

[0002] For example, Patent Document 1 discloses a configuration in which a hydrogen tank as a fuel tank is arranged along the longitudinal direction of the vehicle within a tunnel portion that bulges out from the floor of the vehicle compartment in the body of an automobile.

[0003] However, in Patent Document 1, no consideration is given to increasing the tank capacity of the fuel tank that is placed in the limited vehicle space.

[0004] That is, in a system having a fuel tank disposed within a limited vehicle space, there is room for further improvement in terms of increasing the capacity of the fuel tank.

[0005] Japanese Patent Application Laid-Open No. 2004-26117

[0006] The vehicle fuel tank system of the present invention includes a floor panel disposed on the floor of the vehicle and a fuel tank disposed below the floor panel and oriented along the vehicle longitudinal direction. The floor panel has a flat floor plane portion and a floor tunnel portion that protrudes upward in the vehicle vertical direction relative to the floor plane portion and extends at an angle along the vehicle longitudinal direction. The fuel tank is disposed at an angle within the floor tunnel portion.

[0007] According to the present invention, the overall length of the fuel tank that can be placed inside the floor tunnel section can be increased, thereby increasing the capacity, and the amount of fuel that can be carried in the vehicle can be increased overall.

[0008] 1 is an explanatory diagram showing a schematic overview of a fuel tank system for a vehicle according to the present invention. 2 is an explanatory diagram showing an enlarged view of the fuel tank system for a vehicle according to the present invention. 3 is an explanatory diagram showing an explanatory diagram of the arrangement of a fuel tank relative to a vehicle. 4 is an explanatory diagram showing an explanatory diagram of the arrangement of a fuel tank relative to a vehicle. 5 is an explanatory diagram showing a side view of the fuel tank system for a vehicle according to the present invention. 6 is an explanatory diagram showing an explanatory diagram of a support structure for the other end of a second fuel tank. 7 is an explanatory diagram showing an enlarged view of a fuel supply pipe in a fuel tank system. 8 is an explanatory diagram showing an explanatory diagram of the positional relationship between a first main stop valve, a second main stop valve, and a second fuel supply pipe. 9 is an explanatory diagram showing an explanatory diagram of the positional relationship between the first main stop valve, a second main stop valve, and a second fuel supply pipe. 10 is an explanatory diagram showing an explanatory diagram of the positional relationship between the first main stop valve, a second main stop valve, and a second fuel supply pipe. 11 is an explanatory diagram showing an explanatory diagram of the positional relationship between the first main stop valve, a second main stop valve, and a second fuel supply pipe in a comparative example.

[0009] An embodiment of the present invention will be described in detail below with reference to the drawings.

[0010] Fig. 1 is an explanatory diagram showing a schematic overview of a fuel tank system 2 of a vehicle 1 according to the present invention. Fig. 2 is an explanatory diagram showing an enlarged view of the fuel tank system 2. Figs. 3 and 4 are explanatory diagrams showing a schematic arrangement of a fuel tank 4 relative to the vehicle 1, with Fig. 3 being an explanatory diagram showing the vehicle 1 as viewed from the front (front), and Fig. 4 being an explanatory diagram showing the vehicle 1 as viewed from the side (side).

[0011] 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.

[0012] 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.

[0013] 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).

[0014] 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 .

[0015] 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.

[0016] 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 fuel tank 4 is disposed such that its central axis is aligned with the vehicle longitudinal direction.

[0017] In this embodiment, the multiple fuel tanks 4 include two fuel tanks: a first high-pressure fuel tank 4a located 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 with 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.

[0018] As shown in FIGS. 3 and 4, the first fuel tank 4a and the second fuel tank 4b are disposed below a floor panel P disposed on the floor of the vehicle 1.

[0019] The floor panel P has a flat floor plane portion 27 and a floor tunnel portion 28 that protrudes upward in the vehicle vertical direction relative to the floor plane portion 27 and extends at an angle along the vehicle longitudinal direction. The floor tunnel portion 28 is a protruding portion that bulges out with a U-shaped cross section so as to form a space inside, and is formed at the center of the floor panel P in the vehicle width direction. The floor tunnel portion 28 is what is known as the center tunnel of the car body (vehicle).

[0020] The floor tunnel section 28 has a pair of flat vertical walls 28a extending along the fore-and-aft direction of the vehicle, and a flat top wall 28b connected to the ends of the pair of vertical walls 28a and extending along the fore-and-aft direction of the vehicle.

[0021] The vertical wall 28a is formed so that its upper end (tip) is positioned higher relative to the flat floor portion 27 as it moves toward the front of the vehicle. In other words, as shown in Figure 4, the vertical wall 28a has a wedge shape (triangular shape) in a side view, and the amount of protrusion from the flat floor portion 27 decreases as it moves toward the rear of the vehicle.

[0022] The top wall 28b is formed to be inclined along the longitudinal direction of the vehicle so that the front side of the vehicle is positioned higher than the rear side of the vehicle.

[0023] The first fuel tank 4a and the second fuel tank 4b are disposed in a direction along the front-to-rear direction of the vehicle 1 (the up-and-down direction in FIG. 1 ), and are disposed adjacent to each other (side by side) 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.

[0024] The first fuel tank 4a is disposed within the floor tunnel portion 28 so that its tank central axis is inclined along the vehicle fore-and-aft direction. The tank central axis is the central axis of the fuel tank 4 along the longitudinal direction of the fuel tank 4, and is the central axis of the first fuel tank 4a. The first fuel tank 4a is disposed within the floor tunnel portion 28 so that its one end 22a, which is on the vehicle rear side, is positioned lower in the vehicle up-and-down direction (toward the vehicle lower side) than its other end 23a, which is on the vehicle front side. As a result, a gap with a wedge-shaped cross section (triangular cross section) is formed along the vehicle fore-and-aft direction below the other end 23a of the first fuel tank 4a.

[0025] The second fuel tank 4 b is disposed along the floor plane portion 27 and parallel to the floor plane portion 27 .

[0026] 5 is an explanatory diagram showing a schematic side view (view from the side) of the fuel tank system 2 of the present invention. The first fuel tank 4a and the second fuel tank 4b are located within the subframe 9 and are fixed to the box-shaped subframe 9 with a rectangular outline via brackets 24. The subframe 9 is mounted on the vehicle so as to be parallel to the floor plane portion 27 of the floor panel P.

[0027] The bracket 24 has an upper bracket piece 29 and a lower bracket piece 30 that sandwich the cylindrical (cylindrical) end of the one end 22 or the other end 23 of the fuel tank 4 from above and below (in the radial direction of the end), and supports the end of the one end 22 or the other end 23 of the fuel tank 4. More specifically, the upper bracket piece 29 and the lower bracket piece 30 each have a semicircular support surface that supports the end of the one end 22 or the other end 23 of the fuel tank 4. The lower bracket piece 30 supports the end of the one end 22 or the other end 23 of the fuel tank 4 from below and is fixed to the subframe 9 with bolts 35. The upper bracket piece 29 is located above the end of the one end 22 or the other end 23 of the fuel tank 4 and sandwiches and holds the end of the one end 22 or the other end 23 between the upper bracket piece 29 and the lower bracket piece 30. The upper bracket piece 29 is fixed to the lower bracket piece 30 with bolts 36.

[0028] An end of one end 22a of the first fuel tank 4a is fixed to a width direction member 32 of the subframe 9 by a bracket 24a having an upper bracket piece 29a and a lower bracket piece (not shown). An end of the other end 23a of the first fuel tank 4a is fixed to a width direction member 32 of the subframe 9 by a bracket 24b having an upper bracket piece 29b and a lower bracket piece 30b. An end of one end 22b of the second fuel tank 4b is fixed to a width direction member 32 of the subframe 9 by a bracket 24c having an upper bracket piece 29c and a lower bracket piece 30c. An end of the other end 23b of the second fuel tank 4b is fixed to a width direction member 32 of the subframe 9 by a bracket 24d having an upper bracket piece 29d and a lower bracket piece 30d, as shown in FIG. 6. FIG. 6 is an explanatory diagram schematically showing the support structure for the other end 23b of the second fuel tank 4b. The second fuel tank 4b is supported along and parallel to the bottom surface (lower surface) of the subframe 9 by brackets 24c, 24d that are fixed to width direction members 32b, 32b, respectively, that form the bottom surface (lower surface) of the subframe 9.

[0029] The fuel tank 4 is supported by the subframe 9 via the bracket 24, which improves the ease of mounting on the vehicle 1.

[0030] Brackets 24a and 24b are inclined in accordance with the inclination of first fuel tank 4a. More specifically, brackets 24a and 24b are inclined so as to be perpendicular to the central axis of the inclined first fuel tank 4a. Therefore, width direction members 32 to which lower bracket pieces 30 of brackets 24a and 24b are fixed are formed so as to have inclined surfaces to which the inclined lower bracket pieces 30 can be attached.

[0031] Furthermore, the bottom surface (lower surface) of the subframe 9 may be inclined, for example, along the ramp breakover angle of the vehicle 1. In this case, the subframe 9 will not be parallel to the floor plane portion 27 of the floor panel P, and the second fuel tank 4b within the subframe 9 will be mounted on the vehicle in a state inclined with respect to the ground surface of the vehicle 1.

[0032] 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 through a fill port 13 provided on the side (left side) of the vehicle 1 and via a first fuel supply pipe 6a (details of which will be described later).

[0033] The main stop valve 5 has the function of opening and closing the fuel tank 4, enabling the filling of the fuel tank 4 with fuel and the 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 an internal communication passage (not shown) that connects the first connection port 25 and the second connection port 26.

[0034] The main stop valves 5 include 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.

[0035] The fuel supply pipe 6 allows fuel to pass through it, 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. The fuel supply pipe 6 is a fuel supply path that supplies fuel to the fuel cell 3.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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 located downstream of the pressure reducing valve 7 in the fuel flow direction toward the fuel cell 3, and is a low-pressure pipe through which low-pressure fuel reduced by the pressure reducing valve 7 flows.

[0042] One end of the fifth fuel supply pipe 6e is connected to the fuel cell 3, and the other end is connected to the desulfurizer 8. In other words, one end of the fifth fuel supply pipe 6e is attached and fixed to the fuel cell 3, and the other end is 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.

[0043] The pressure reducing valve 7 reduces (adjusts) the pressure of the fuel from the fuel tank 4 to a predetermined pressure and supplies it downstream (to the fuel cell side).The pressure reducing valve 7 is located downstream of the fuel tank 4 and upstream of the desulfurizer 8 in the fuel flow direction toward the fuel cell 3.

[0044] The desulfurizer 8 corresponds to an on-vehicle component, and is disposed adjacent to the first fuel tank 4a on the opposite side (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 direction of fuel flow 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.

[0045] The desulfurizer 8 is located below the floor panel P. The desulfurizer 8 is disposed along the floor flat surface 27 of the floor panel P. The desulfurizer 8 is a component having an elongated shape along the vehicle longitudinal direction, and is disposed so that its end portion on the vehicle front side fits into a gap formed below the other end 23a of the first fuel tank 4a. That is, in a plan view, the desulfurizer 8 is disposed obliquely so that its end portion on the vehicle front side is located below the other end 23a of the first fuel tank 4a and overlaps with the first fuel tank 4a, and its end portion on the vehicle rear side is located outside the first fuel tank 4a and does not overlap with the first fuel tank 4a. In other words, a portion of the desulfurizer 8 on the vehicle front side is disposed below the other end 23a of the first fuel tank 4a in the vehicle vertical direction.

[0046] 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.

[0047] 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 multiple 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 multiple cross members 15 are connected to each other, forming an overall ladder shape.

[0048] 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 lidless rectangular box that surrounds the first and second fuel tanks 4a, 4b, the pressure reducing valve 7, and the desulfurizer 8. The subframe 9 is fixed to the cross member 15, for example.

[0049] 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.

[0050] The 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 width direction members 32 are connected to the one-side longitudinal direction member 31a and the other-side longitudinal direction member 31b on both sides, respectively.

[0051] The vertical members 33 are located, for example, at least at the four corners of the subframe 9 .

[0052] 7, 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. 7 is an explanatory diagram showing an enlarged view of the fuel supply pipe 6 of the fuel tank system 2.

[0053] 7, the rear width direction members 32a are 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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 in the vehicle vertical direction 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 are located higher than the height positions in the vehicle vertical direction 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 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 different height positions 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.

[0059] As shown in Fig. 8, the second fuel supply pipe 6b in the fuel tank system 2 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. 8. Fig. 8 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.

[0060] As shown in FIG. 8, 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.

[0061] 7 to 9, 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.

[0062] Fig. 9 is an explanatory diagram showing a schematic 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. 10 is an explanatory diagram showing a schematic 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.

[0063] 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.

[0064] 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.

[0065] The first bent portion 41 a is a bent portion on the XY plane that includes the X-axis and the Y-axis, and is a portion where the second fuel supply pipe 6 b extending from the first main stop valve 5 a along the vehicle width direction is bent rearward in the vehicle front-rear direction. The first bent portion 41 a is a two-dimensional bend on the XY plane.

[0066] The second bent portion 41b 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 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.

[0067] 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.

[0068] The fourth bent portion 41 d is a portion where the second fuel supply pipe 6 b, which extends obliquely from the second bent portion 41 b in the vehicle longitudinal direction and the vehicle vertical direction, is bent in the vehicle width direction and is bent so that its height position does not change in the vehicle vertical direction. The fourth bent portion 41 d is a three-dimensional bend that combines two-dimensional bending on the XY plane and two-dimensional bending on the YZ plane.

[0069] 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. Because 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, 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.

[0070] The first main stop valve 5a and the second main stop valve 5b may be partially overlapped in the vertical direction of the vehicle.

[0071] In the fuel tank system 2 of the above-described embodiment, for example, when the fuel tank is arranged horizontally in the floor tunnel portion 28, the fuel tank can be considered to be arranged along the base of a right triangle whose base is aligned with the bottom surface of the vehicle 1. On the other hand, the first fuel tank 4a of the above-described embodiment is arranged at an angle in the floor tunnel portion 28, and therefore can be considered to be arranged along the hypotenuse of a right triangle whose base is aligned with the bottom surface of the vehicle 1.

[0072] In other words, in the fuel tank system 2 of the above-described embodiment, by disposing the first fuel tank 4a at an angle within the floor tunnel portion 28, it is possible to increase the overall length of the first fuel tank 4a within the limited vehicle space without increasing the installation space length of the first fuel tank 4a along the fore-and-aft direction of the vehicle in a plan view of the vehicle.

[0073] That is, by arranging the first fuel tank 4a at an angle within the floor tunnel portion 28, the overall length that can be arranged within the floor tunnel portion 28 can be increased, thereby increasing the capacity, and overall the amount of fuel that can be carried in the vehicle 1. Note that the circumferential stress and axial stress due to internal pressure of the first fuel tank 4a are not affected by the tank length.

[0074] Furthermore, by arranging the first fuel tank 4a within the floor tunnel portion 28 of the floor panel P, the fuel tank system 2 can tilt the first fuel tank 4a while suppressing the impact (rebound) on the minimum ground clearance of the vehicle 1.

[0075] In the fuel tank system 2, the desulfurizer 8 is disposed at an angle in a plan view so that a portion of the desulfurizer 8 on the vehicle front side is located below the other end 23a of the first fuel tank 4a. In other words, the fuel tank system 2 can effectively utilize the space below the first fuel tank 4a that is created by disposing the first fuel tank 4a at an angle. As a result, the fuel tank system 2 can improve the layout freedom when arranging the desulfurizer 8 adjacent to the first fuel tank 4a. In other words, the fuel tank system 2 can improve the layout freedom when arranging the on-vehicle components to be disposed around the first fuel tank 4a.

[0076] In the fuel tank system 2, the fuel supply pipe 6 is fixed to the subframe 9, which is a vehicle structural member, and therefore vibrations of the fuel supply pipe 6 caused by pulsation when fuel is supplied from the fuel tank 4 to the fuel cell 3 are prevented from being transmitted into the vehicle cabin. Therefore, the fuel tank system 2 reduces vibrations and noise felt inside the vehicle cabin due to vibrations of the fuel supply pipe 6 caused by pulsation of fuel supplied to the fuel cell 3, thereby improving the ride comfort of passengers inside the vehicle 1.

[0077] If the position of the second main stop valve 5b attached to the second fuel tank 4b changes due to some external input, the first fuel supply pipe 6a will be twisted around the position of one end fixed to the second main stop valve 5b. However, since the attachment position relative to the second main stop valve 5b and the attachment position relative to the rear width direction member 32ab, which is a vehicle structural member, are at different positions (heights) in the vertical direction of the vehicle, it is possible to reduce buckling stress and improve durability and reliability.

[0078] Furthermore, if the position of the first main stop valve 5a attached to the first fuel tank 4a changes due to some external input, the second fuel supply pipe 6b will twist around the position of one end fixed to the first main stop valve 5a, but because the attachment position relative to the first main stop valve 5a and the attachment position relative to the rear width direction member 32aa, which is a vehicle structural member, are different positions (heights) in the vehicle up-down direction, buckling stress can be reduced and durability reliability can be improved. Furthermore, if the position of the second main stop valve 5b attached to the second fuel tank 4b changes due to some external input, the second fuel supply pipe 6b will twist around the position of the other end fixed to the second main stop valve 5b, but because the attachment position relative to the second main stop valve 5b and the attachment position relative to the rear width direction member 32aa, which is a vehicle structural member, are different positions (heights) in the vehicle up-down direction, buckling stress can be reduced and durability reliability can be improved.

[0079] In other words, in the fuel tank system 2, even if the position of the fuel tank 4 changes from its initial fixed position (arrangement position) due to an unintended external input or the like, the attachment position of the fuel supply pipe 6 to the main stop valve 5 of the fuel tank 4 and the attachment position of the fuel supply pipe 6 to the subframe 9, which is a vehicle structural member, are different positions in the vertical direction of the vehicle, so that buckling stress can be reduced and durability reliability can be improved.

[0080] 11 , 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 vehicle width direction, 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 an additional auxiliary bend 52 provided.

[0081] 11 is an explanatory diagram illustrating a comparative example in the above-described embodiment, in which the first main stop valve 5a and the second main stop valve 5b are positioned at the same height in the vehicle up-down direction, and the fuel supply pipe 51 is connected to the first main stop valve 5a and the second main stop valve 5b from the same direction in the vehicle width direction. In the comparative example shown in FIG. 11, 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 bend 52a and a second auxiliary bend 52b are formed so that the second main stop valve 5b can be moved in the vehicle up-down direction.

[0082] 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.

[0083] In contrast, in the fuel tank system 2 of the above-described embodiment, the 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. The fuel tank system 2 is arranged so that the pair of fuel tanks 4 have the first main stop valve 5a and the second main stop valve 5b 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.

[0084] 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 vertical 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.

[0085] 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 likely to be restricted by the main stop valve 5 compared to when the main stop valves 5 of a pair of adjacent fuel tanks 4 are at the same height position along the vehicle vertical 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.

[0086] 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, it is possible to combine fuel tanks 4 with the largest diameters appropriate for the installation position, thereby efficiently increasing the amount of fuel that can be carried.

[0087] 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.

[0088] For example, the first fuel supply pipe 6a and the second fuel supply pipe 6b may be fixed to the same rear width direction member 32a as long as the attachment position of the fuel supply pipe 6 relative to the main stop valve 5 and the attachment position of the fuel supply pipe 6 relative to the rear width direction member 32a can be at different heights in the vehicle up-down direction. In other words, the first fuel supply pipe 6a and the second fuel supply pipe 6b may be fixed to either the rear width direction member 32aa or the rear width direction member 32ab as long as the attachment position of the fuel supply pipe 6 relative to the main stop valve 5 and the attachment position of the fuel supply pipe 6 relative to the rear width direction member 32a can be at different heights in the vehicle up-down direction. In this case, the rear width direction member 32aa or the rear width direction member 32ab to which the first fuel supply pipe 6a and the second fuel supply pipe 6b are not fixed may be omitted. In other words, if the mounting position of the fuel supply pipe 6 relative to the main stop valve 5 and the mounting position of the fuel supply pipe 6 relative to the rear width direction member 32a can be at different height positions in the vertical direction of the vehicle, one of the rear width direction members 32aa and 32ab may be omitted.

[0089] For example, the fuel supply pipe 6 of the fuel tank system 2 may be fixed to the cross member 15 via the clip member 16 instead of the subframe 9. Furthermore, in the fuel tank system 2, the fuel supply pipe 6 may be fixed to the cross member 15 as long as the attachment position of the fuel supply pipe 6 relative to the main stop valve 5 and the attachment position of the fuel supply pipe 6 relative to the vehicle structural member are different positions in the vertical direction of the vehicle.

[0090] For example, the second fuel tank 4b may be disposed in a state inclined with respect to the longitudinal direction of the vehicle. In other words, the multiple fuel tanks 4 may be disposed horizontally, and at least one fuel tank 4 may be disposed in a state inclined with respect to the longitudinal direction of the vehicle in a plan view of the vehicle.

[0091] The fuel tank 4 that is disposed at an angle with respect to the vehicle's fore-and-aft direction in a plan view of the vehicle can increase the length of the fuel tank 4 while maintaining the length of the fuel tank installation space along the vehicle's fore-and-aft direction. In other words, the fuel tank 4 that is disposed at an angle with respect to the vehicle's fore-and-aft direction in a plan view of the vehicle can increase the length that can be placed in the fuel tank installation space, and therefore the capacity of the fuel tank 4 can be increased.

[0092] For example, as shown by the dashed line in Figure 8, the second fuel supply pipe 6b may pass below the first main stop valve 5a in the vertical direction of the vehicle and be connected to the second main stop valve 5b from the other side in the vehicle width direction.

[0093] 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.

Claims

1. A fuel tank system for a vehicle comprising: a floor panel arranged on the floor of the vehicle; and a cylindrical fuel tank arranged below the floor panel in a direction along the fore-and-aft direction of the vehicle, wherein the floor panel has a flat floor plane portion and a floor tunnel portion that protrudes upward in the vehicle's up-and-down direction relative to the floor plane portion and extends at an angle along the fore-and-aft direction of the vehicle, and wherein the fuel tank is arranged at an angle within the floor tunnel portion.

2. A fuel tank system for a vehicle as set forth in claim 1, wherein the floor tunnel section is formed at an incline so that the front side of the vehicle is positioned higher than the rear side of the vehicle, and the fuel tank is arranged at an incline so that one end located at the rear of the vehicle is positioned lower than the other end located at the front of the vehicle.

3. A vehicle fuel tank system as described in claim 2, further comprising a second fuel tank disposed below the floor panel in a direction along the vehicle longitudinal direction, the second fuel tank being adjacent to the fuel tank in the vehicle width direction and disposed along the floor plane.

4. A vehicle fuel tank system as described in claim 3, further comprising an on-board component arranged on the opposite side of the second fuel tank across the fuel tank in the vehicle width direction, the on-board component being arranged along the floor plane.

5. A vehicle fuel tank system as set forth in claim 3, comprising: a first main stop valve connected to the fuel tank; a second main stop valve connected to the second fuel tank; and a fuel pipe having one end connected to the fuel tank via the first main stop valve and the other end connected to the second fuel tank via the second main stop valve, wherein the fuel pipe is fixed to a vehicle structural member extending along the width direction of the vehicle.

6. A vehicle fuel tank system as described in claim 5, wherein the fuel pipe is connected to the first main stop valve and the second main stop valve from the same direction in the vehicle width direction, and the fuel tank and the second fuel tank are arranged so that the first main stop valve and the second main stop valve are located on the same side in the vehicle longitudinal direction, and the first main stop valve and the second main stop valve are located at different height positions in the vehicle vertical direction.

7. A fuel tank system for a vehicle according to claim 2, wherein an on-vehicle component is disposed below the other end of the fuel tank in the vertical direction of the vehicle.

Images