Vehicle underbody structure

A vehicle underbody structure includes a pair of rockers that are provided on both vehicle width direction sides of a vehicle underbody and extend in a vehicle front-rear direction, a battery that is disposed centrally in a vehicle width direction center between the pair of rockers and is disposed above a vehicle floor and on the lower side of a seat, a fuel tank that is disposed in the vehicle width direction center between the pair of rockers and is disposed under the vehicle floor and further toward a rear side of the vehicle than the battery, and a waste pipe that is coupled to a drive unit provided at a vehicle front side of the battery and extends in the vehicle front-rear direction between the battery and one of the rockers.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2018-150691 filed on Aug. 9, 2018, the disclosure of which is incorporated by reference herein.

BACKGROUND

Technical Field

The present disclosure relates to a vehicle underbody structure.

Related Art

Japanese Patent Application Laid-open (JP-A) No. 2017-081211 discloses a vehicle underbody structure where side sills (rockers) that extend along the vehicle front-rear direction are provided on both right and left sides of a vehicle underbody and where a hydrogen tank, a battery, and an exhaust gas pipe are disposed on the lower side of a floor panel that bridges the side sills.

However, in the related art described above, uneven portions are formed in the undersurface of the vehicle by vehicle body members mounted to the lower side of the floor panel and the air resistance of the vehicle underbody increases, whereby the aerodynamic performance of the vehicle is reduced.

Furthermore, when the height from the road surface to the vehicle undersurface is ensured, it becomes difficult to reduce the vehicle height.

SUMMARY

Thus, the present disclosure provides to obtain a vehicle underbody structure that can improve the aerodynamic performance of the underfloor and at the same time can reduce the vehicle height.

A vehicle underbody structure pertaining to a first aspect of the disclosure includes a pair of rockers that are provided at both vehicle width direction sides of a vehicle underbody and extend in a vehicle front-rear direction, a battery that is disposed centrally in a vehicle width direction between the pair of rockers and is disposed above a vehicle floor and at a lower side of a seat, a fuel tank that is disposed in the vehicle width direction center between the pair of rockers and is disposed under the vehicle floor and more in the vehicle rearward direction than the battery, and a waste pipe that is coupled to a drive unit provided at a vehicle front side of the battery and extends in the vehicle front-rear direction between the battery and one of the rockers.

In the vehicle underbody structure pertaining to the first aspect of the disclosure, the battery disposed in the vehicle width direction center between the pair of rockers is disposed above the vehicle floor and on the lower side of the seat. For this reason, compared to a case where the battery is disposed under the vehicle floor, uneven portions formed in the vehicle undersurface centered around the center of the vehicle underfloor are reduced. Moreover, the waste pipe coupled to the drive unit extends in the vehicle front-rear direction between the battery and one of the rockers, so compared to a structure where the waste pipe is disposed along the vehicle front-rear direction in the center of the vehicle underfloor, uneven portions formed in the center of the vehicle underfloor can be further reduced. Because of this, the aerodynamic performance of the underfloor is improved.

Furthermore, the structure of the vehicle underfloor can be thinned in the vehicle up and down direction in correspondence to the battery being disposed above the vehicle floor and on the lower side of the seat, so even if the height from the road surface to the vehicle undersurface is ensured, the vehicle height can be reduced.

A vehicle underbody structure pertaining to a second aspect of the disclosure is the vehicle underbody structure of the first aspect, wherein the battery and the fuel tank are disposed at positions that overlap with the rockers as seen in a vehicle side view.

In the vehicle underbody structure pertaining to the second aspect of the disclosure, the battery and the fuel tank are disposed at positions that overlap with the rockers as seen in a vehicle side view. For this reason, for example, compared to a configuration where the battery and the fuel tank are disposed on the lower side of the rockers as seen in a vehicle side view, the formation of dead space is inhibited. Furthermore, height differences in the installation positions of the battery and the fuel tank can be inhibited, so the formation of uneven portions can be reduced in a wide range of the vehicle undersurface centered around the center of the vehicle underfloor. Because of this, the aerodynamic performance of the underfloor is further improved.

A vehicle underbody structure pertaining to a third aspect of the disclosure is the vehicle underbody structure of the first aspect or the second aspect, further including a pair of first frame members that are respectively disposed between one or another of the pair of rockers and the battery and extend in the vehicle front-rear direction and second frame members that couple the first frame members to each other in the vehicle width direction and are respectively disposed at least between the battery and the drive unit and between the battery and the fuel tank as seen in a vehicle plan view.

In the vehicle underbody structure pertaining to the third aspect of the disclosure, the four sides of the battery are surrounded by frame members as seen in a vehicle plan view by the pair of first frame members that extend in the vehicle front-rear direction and the second frame members that couple the first frame members to each other in the vehicle width direction. Because of this, the battery can be protected from the load input to the vehicle body at the time of an impact to the vehicle.

A vehicle underbody structure pertaining to a fourth aspect of the disclosure is the vehicle underbody structure of any one of the first aspect to the third aspect, wherein the battery is disposed at a lower side of at least one of a driver's seat or a front passenger seat.

In the vehicle underbody structure pertaining to the fourth aspect of the disclosure, the battery is disposed at a lower side of at least one of the driver's seat or a front passenger seat, whereby the battery is disposed on the front side of the vehicle. Because of this, space for mounting the fuel tank under the rear seat or the luggage compartment on the vehicle rear side can be ensured, so the tank capacity can be sufficiently ensured.

A vehicle underbody structure pertaining to a fifth aspect of the disclosure is the vehicle underbody structure of any one of the first aspect to the fourth aspect, wherein the drive unit is configured to include an inverter, and the inverter and the battery are coupled to each other by a high-voltage cable.

In the vehicle underbody structure pertaining to the fifth aspect of the disclosure, the drive unit is provided on the vehicle front side of the battery, and the inverter and the battery that configure the drive unit are coupled to each other by the high-voltage cable. For this reason, compared to a structure where vehicle-mounted members such as the fuel tank are disposed between the drive unit and the battery, the distance between the battery and the inverter is short and the length of the high-voltage cable can be shortened. As a result, current loss between the battery and the inverter is inhibited.

A vehicle underbody structure pertaining to a sixth aspect of the disclosure is the vehicle underbody structure of any one of the first aspect to the fifth aspect, wherein the fuel tank is a gasoline tank, the drive unit is configured to include a gasoline engine, and the waste pipe is an exhaust gas pipe that discharges, to outside of the vehicle, exhaust gas from the gasoline engine.

In the vehicle underbody structure pertaining to the sixth aspect of the disclosure, uneven portions formed in the center of the vehicle undersurface are reduced and the vehicle underbody structure is thinned in the vehicle up and down direction in a hybrid vehicle where the gasoline tank and the battery are mounted to the vehicle underbody. Because of this, the aerodynamic performance of the underfloor of the hybrid vehicle can be improved and at the same time the vehicle height can be reduced.

A vehicle underbody structure pertaining to a seventh aspect of the disclosure is the vehicle underbody structure of any one of the first aspect to the fifth aspect, wherein the fuel tank is a hydrogen tank, the drive unit is configured to include a fuel cell stack, and the waste pipe is a water discharge pipe that discharges, to outside of the vehicle, waste water from the fuel cell stack.

In the vehicle underbody structure pertaining to the seventh aspect of the disclosure, uneven portions formed in the center of the vehicle undersurface are reduced and the vehicle underbody structure is thinned in the vehicle up and down direction in a fuel cell vehicle where the hydrogen tank and the battery are mounted to the vehicle underbody. Because of this, the aerodynamic performance of the underfloor of the fuel cell vehicle can be improved and at the same time the vehicle height can be reduced.

According to the vehicle underbody structure of the first aspect of the disclosure, the vehicle underbody structure has the superior effect that the aerodynamic performance of the underfloor can be improved and at the same time the vehicle height can be reduced.

According to the vehicle underbody structure of the second aspect of the disclosure, the vehicle underbody structure has the superior effect that the formation of uneven portions can be reduced in a wide range of the vehicle undersurface and the aerodynamic performance of the underfloor can be further improved.

According to the vehicle underbody structure of the third aspect of the disclosure, the vehicle underbody structure has the superior effect that the battery can be protected from the load input to the vehicle body at the time of an impact to the vehicle.

According to the vehicle underbody structure of the fourth aspect of the disclosure, the vehicle underbody structure has the superior effect that space for mounting the fuel tank under the rear seat or the luggage compartment on the vehicle rear side can be ensured and the tank capacity can be sufficiently ensured.

According to the vehicle underbody structure of the fifth aspect of the disclosure, the vehicle underbody structure has the superior effect that the length of the high-voltage cable can be shortened and current loss between the battery and the inverter can be inhibited because the distance between the battery and the inverter is short.

According to the vehicle underbody structure of the sixth aspect of the disclosure, the vehicle underbody structure has the superior effect that the aerodynamic performance of the underfloor of a hybrid vehicle can be improved and at the same time the vehicle height can be reduced.

According to the vehicle underbody structure of the seventh aspect of the disclosure, the vehicle underbody structure has the superior effect that the aerodynamic performance of the underfloor of a fuel cell vehicle can be improved and at the same time the vehicle height can be reduced.

DETAILED DESCRIPTION

First Embodiment

A first embodiment of a vehicle underbody structure pertaining to the disclosure will be described below on the basis ofFIG.1toFIG.4. It will be noted that, for convenience of description, arrow UP appropriately shown in the drawings indicates a vehicle body upward direction, arrow FR indicates a vehicle body forward direction, and arrow RH indicates a rightward direction in the vehicle width direction. Furthermore, when the directions of upper/lower, front/rear, and right/left are used with further specification in the following description, these will be understood to mean upper/lower in the vehicle body up and down direction, front/rear in the vehicle body front-rear direction, and right/left in the vehicle body right and left direction (the vehicle width direction). Furthermore, there are cases where some reference signs are omitted in the drawings to make it easier to see what is shown in the drawings.

FIG.1is a bottom view showing a vehicle underbody of a vehicle10equipped with the vehicle underbody structure pertaining to the present embodiment. As shown in this drawing, the vehicle10has, on the vehicle underbody, a right and left pair of rockers12, a right and left pair of side frames14, and plural (in the present embodiment, four) cross members16, all of which serve as frame members. Furthermore, a floor panel18is disposed on the vehicle upper side of the frame members.

Furthermore, the vehicle10is a hybrid vehicle and has two drive sources, a gasoline engine22and a traveling motor24, in a drive unit20provided in the vehicle front portion. The gasoline engine22is an internal combustion engine that uses gasoline retained in a gasoline tank26as fuel, and exhaust gas generated by the gasoline engine22is exhausted through an exhaust gas pipe28to the outside of the vehicle. Furthermore, the traveling motor24is driven when it receives a supply of electric power from a battery30via an inverter32in the drive unit20.

Each of the constituent elements will be described in detail below. It will be noted that the side frames14correspond to “first frame members” of the disclosure and that the cross members16correspond to “second frame members” of the disclosure. Furthermore, the floor panel18corresponds to a “floor” of the vehicle of the disclosure, the vehicle lower side of the floor panel18means “under the vehicle floor,” and the vehicle upper side of the floor panel18means “above the vehicle floor.” Furthermore, the exhaust gas pipe28corresponds to a “waste pipe” of the disclosure.

As shown inFIG.1toFIG.3, the rockers12are frame members that are provided as a right and left pair on both vehicle width direction sides of the vehicle underbody of the vehicle10and extend in the vehicle front-rear direction. The rockers12are disposed on the lower sides of side doors34of the vehicle10and configure doorsill portions between the vehicle interior and the vehicle exterior. It will be noted that, for convenience of description, illustration of an inlet pipe27is omitted inFIG.2andFIG.3.

As shown inFIG.4, each rocker12is formed in the shape of a hollow tube and has a rocker outer member36disposed on the vehicle width direction outer side and a rocker inner member38disposed on the vehicle width direction inner side. The cross section of the rocker outer member36perpendicular to the direction in which the rocker outer member36extends is formed in the shape of a hat that opens inward in the vehicle width direction and becomes convex outward in the vehicle width direction. The cross section of the rocker inner member38perpendicular to the direction in which the rocker inner member38extends is formed in the shape of a hat that opens outward in the vehicle width direction and becomes convex inward in the vehicle width direction. The rocker outer member36and the rocker inner member38are joined to each other at their respective upper end portions and lower end portions to form a closed cross section.

The floor panel18is formed substantially in the shape of a rectangular plate as seen in a plan view, and vehicle width direction outer end portions18A of the floor panel18are joined to the rocker inner members38of the right and left pair of rockers12. Because of this, the floor panel18bridges the pair of rockers12.

Furthermore, a substantially rectangular recess portion whose longitudinal direction coincides with the vehicle width direction is formed in the center of the front portion of the floor panel18, and the recess portion is configured to serve as a placement portion40for the battery30, which is disposed on top of the floor panel18. The placement portion40is provided on the inner side of the later-described right and left pair of side frames14as seen in a plan view. Furthermore, the middle portion of the floor panel18bulges convexly upward in the vehicle upward direction between the right and left rockers12, thereby forming a space portion42on the lower side of the floor panel18. The space portion42serves as a space for mounting the gasoline tank26. That is, the battery30and the gasoline tank26are disposed in such a way as to overlap (coincide with) the rockers12as seen from the side in the vehicle width direction.

As shown inFIG.3, a driver's seat44and a front passenger seat46are provided side by side in the vehicle width direction on the upper side of the placement portion40of the floor panel18. Furthermore, a rear seat48is provided on the upper side of the space portion42. Additionally, a luggage compartment49of the vehicle10is provided on the upper side of the rear portion of the floor panel18.

The right and left pair of side frames14are provided on the undersurface of the floor panel18on both vehicle width direction sides. The side frames14are frame members that extend in the vehicle front-rear direction. The side frames14are disposed on the vehicle width direction inner sides of the right and left pair of rockers12. The cross section of each side frame14perpendicular to the direction in which the side frame14extends is formed in the shape of a hat that opens in the vehicle upward direction and becomes convex in the vehicle downward direction. Additionally, both vehicle width direction right and left end portions of each side frame14are joined to the undersurface of the floor panel18.

Furthermore, plural cross members16that couple the pair of side frames14to each other in the vehicle width direction are provided between the right and left pair of side frames14. In the present embodiment, four cross members16bridge the right and left side frames14, so that a first member16A, a second member16B, a third member16C, and a fourth member16D are disposed in this order from the vehicle front side. The first member16A to the fourth member16D are each configured as a frame member whose cross section perpendicular to the direction in which the member extends is formed in a closed cross-sectional rectangular shape, and the first member16A to the fourth member16D bridge the pair of side frames14at intervals apart from each other in the vehicle front-rear direction. Because of this, a frame that is ladder-shaped as seen in a plan view is formed by the side frames14and the cross members16.

Furthermore, a right and left pair of inner side frames15that extend substantially parallel to the side frames14are provided on the vehicle width direction inner sides of the pair of side frames14. The inner side frames15branch inward in the vehicle width direction from the front end portions of the side frames14and extend in the vehicle rearward direction, and the rear end portions of the inner side frames15are coupled to the third member16C.

Furthermore, a right and left pair of front side members50are coupled to the front end portions of the side frames14. The front side members50extend in the vehicle front-rear direction, are disposed on the inner sides of a right and left pair of front wheels52, and configure frame members of the vehicle front portion. A bumper reinforcement54bridges the front end portions of the pair of front side members50. A right and left pair of rear side members56are coupled to the rear end portions of the side frames14. The rear side members56extend in the vehicle front-rear direction, are disposed on the inner sides of a right and left pair of rear wheels58, and configure frame members of the vehicle rear portion. Additionally, a bumper reinforcement54bridges the rear end portions of the pair of rear side members56. It will be noted that, as shown inFIG.1, the side frames14are offset outward in the vehicle width direction from the front side members50and the rear side members56as seen in a plan view.

As shown inFIG.1toFIG.4, the battery30and the gasoline tank26are both disposed in the vehicle width direction center and are arranged in this order from the vehicle front side. Furthermore, the battery30and the gasoline tank26are disposed more inward in the vehicle width direction than the right and left pair of side frames14.

The battery30is formed substantially in the shape of a rectangle whose vehicle width direction sides are longer than its vehicle body front-rear direction sides as seen in a plan view, and the battery30has numerous battery cells (not shown in the drawings) inside. As mentioned above, the battery30is accommodated in the placement portion40provided in the front portion and upper surface of the floor panel18. The battery30is secured via the floor panel18to the inner side frames15, which are disposed in such a way as to coincide with the placement portion40as seen in a plan view. Because of this, the battery30is disposed on the upper side of the floor panel18and on the lower side of the driver's seat44and the front passenger seat46. Furthermore, the battery30is disposed in such a way as to coincide with the rockers12as seen in a vehicle side view.

Moreover, in this state, the battery30is disposed between the first member16A and the second member16B that configure the cross members16as seen in a plan view. Because of this, the four sides of the battery30are surrounded by the pair of side frames14, the first member16A, and the second member16B as seen in a plan view.

The gasoline tank26is formed substantially in the shape of a trapezoid whose vehicle width direction sides are longer than its vehicle body front-rear direction sides as seen in a plan view, and the gasoline tank26can store gasoline inside. As mentioned above, the gasoline tank26is accommodated in the space portion42provided on the lower side of the middle portion of the floor panel18and is disposed in such a way as to coincide with the rockers12as seen in a vehicle side view. Furthermore, the third member16C and the fourth member16D that configure the cross members16are disposed in this order from the vehicle front side on both vehicle front-rear direction sides of the gasoline tank26. Because of this, the four sides of the gasoline tank26are surrounded by the pair of side frames14, the third member16C, and the fourth member16D as seen in a plan view. Furthermore, the gasoline tank26is secured to the third member16C and the fourth member16D via tank belts not shown in the drawings. Because of this, the gasoline tank26is supported by the frame members of the vehicle body. It will be noted that the rear end of the gasoline tank26is communicated, via an inlet pipe27, with a fuel fill inlet (not shown in the drawings) provided in the right side portion of the vehicle rear portion, so that gasoline can be supplied to the inside of the tank via this fuel fill inlet.

The drive unit20is provided on the front side of the battery30on the vehicle width direction inner sides of the right and left pair of front side members50. The drive unit20is configured to include the gasoline tank26, the traveling motor24, and the inverter32. As mentioned above, the battery30and the traveling motor24are connected to each other via the inverter32. Furthermore, the battery30and the inverter32are coupled to each other by a high-voltage cable60. By disposing the battery30on the rear side of the drive unit20in this way, the high-voltage cable60interconnecting the battery30and the inverter32can be shortened.

Furthermore, the gasoline engine22that configures the drive unit20is connected to the exhaust gas pipe28via a manifold not shown in the drawings. The exhaust gas pipe28comprises a cylindrical pipe and has the function of exhausting, to the outside of the vehicle, exhaust gas exhausted from the gasoline engine22that is an internal combustion engine.

The exhaust gas pipe28is disposed on the lower side of the floor panel18and extends from the drive unit20to the rear end of the vehicle10. Specifically, the part of the exhaust gas pipe28from its front end portion to its middle portion is disposed in such a way as to extend along the vehicle front-rear direction from the drive unit20, bend outward in the vehicle width direction on the front side of the battery30, and cross in front of the battery30as seen in a plan view. Then, the exhaust gas pipe28extends in the vehicle rearward direction along the vehicle width direction right side of the battery30and the gasoline tank26. In this way, the exhaust gas pipe28is disposed in avoidance of the vehicle width direction center of the undersurface of the floor panel18, so uneven portions resulting from the exhaust gas pipe28are not formed in the vehicle width direction center of the undersurface of the floor panel18.

Furthermore, the exhaust gas pipe28is disposed between the battery30and the gasoline tank26on one side and the side frame14on the other on the vehicle width direction right side of the battery30and the gasoline tank26. Consequently, if an impact load is input to the right side portion of the vehicle10, the load is transmitted to the side frame14as the rocker12becomes deformed inward in the vehicle width direction. Because of this, the battery30, the gasoline tank26, and the exhaust gas pipe28that are disposed on the vehicle width direction inner side of the side frames14are protected from the impact load. It will be noted that the exhaust gas pipe28may also be disposed between the rocker12and the side frame14on the vehicle width direction right side of the battery30and the gasoline tank26. Furthermore, the exhaust gas pipe28may also be disposed on the vehicle width direction left side of the battery30and the gasoline tank26.

Next, the action and effects of the vehicle underbody structure pertaining to the present embodiment will be described.

In the vehicle10to which the vehicle underbody structure pertaining to the present embodiment has been applied, the battery30is disposed in the vehicle width direction center between the pair of rockers12. The battery30is disposed on the vehicle upper side of the floor panel18and on the lower side of the driver's seat44and the front passenger seat46. For this reason, compared to a case where the battery30is disposed on the vehicle lower side of the floor panel18, uneven portions formed in the center of the lower side of the floor panel18are reduced. Moreover, the exhaust gas pipe28coupled to the drive unit20extends in the vehicle front-rear direction between the battery30and the rockers12. For this reason, for example, compared to a structure where the exhaust gas pipe is disposed on the lower side of the floor panel18and along the vehicle front-rear direction in the vehicle width direction center, uneven portions formed in the center of the lower side of the floor panel18can be further reduced. Because of this, the aerodynamic performance of the underfloor can be improved.

Furthermore, the structure of the lower side of the floor panel18can be thinned in the vehicle up and down direction in correspondence to the battery30being disposed on the vehicle upper side of the floor panel18and on the lower side of the driver's seat44and the front passenger seat46. For this reason, even if the height from the road surface to the vehicle undersurface is ensured, the vehicle height can be reduced.

Furthermore, in the present embodiment, the battery30and the gasoline tank26are disposed in such a way as to coincide with the rockers12as seen in a vehicle side view. For this reason, for example, compared to a configuration where the battery30and the gasoline tank26are disposed on the lower side of the rockers12as seen in a vehicle side view, the formation of dead space is inhibited. Furthermore, height differences in the installation positions of the battery30and the gasoline tank26can be inhibited, so the formation of uneven portions can be reduced in a wide range of the vehicle undersurface centered around the center of the lower side of the floor panel18. Because of this, the aerodynamic performance of the underfloor is further improved.

Furthermore, in the present embodiment, the four sides of the battery30are surrounded by frame members as seen in a vehicle plan view by the pair of side frames14that extend in the vehicle front-rear direction and the first member16A and the second member16B that couple the side frames14to each other in the vehicle width direction. Because of this, the battery30can be protected from the load input to the vehicle body at the time of an impact to the vehicle.

Furthermore, in the present embodiment, the battery30is disposed on the lower side of the driver's seat44and the front passenger seat46, whereby the battery30is disposed on the front side of the vehicle10. Because of this, space for mounting the gasoline tank26on the lower side of the rear seat48or the luggage compartment49on the vehicle rear side can be ensured, so the tank capacity can be sufficiently ensured.

Furthermore, in the present embodiment, the drive unit20is provided on the vehicle front side of the battery30, and the inverter32and the battery30that configure the drive unit20are coupled to each other by the high-voltage cable60. For this reason, compared to a structure where the gasoline tank26is disposed between the drive unit20and the battery30, the distance between the battery30and the inverter32is short and the length of the high-voltage cable60can be shortened. As a result, current loss between the battery30and the inverter32is inhibited.

In this way, in the present embodiment, the aerodynamic performance of the underfloor of the hybrid vehicle can be improved and at the same time the vehicle height can be reduced.

Moreover, in the present embodiment, the four sides of the gasoline tank26are surrounded by frame members as seen in a plan view by the pair of side frames14that extend in the vehicle front-rear direction and the third member16C and the fourth member16D that couple the side frames14to each other in the vehicle width direction. Because of this, the gasoline tank26can be protected from the load input to the vehicle body at the time of an impact to the vehicle.

Furthermore, in the present embodiment, the side frames14are offset outward in the vehicle width direction from the front side members50and the rear side members56as seen in a plan view. For this reason, in the center of the vehicle underbody the space on the inner side of the pair of side frames14is enlarged, resulting in enlarged capacities for the battery30and the gasoline tank26and an enhancement in design flexibility.

Furthermore, the distance between the rockers12and the side frames14is shortened in correspondence to the side frames14being offset outward in the vehicle width direction. For this reason, at the time of a side impact to the vehicle, the load input to the rockers12is transmitted at an early stage to the side frames14and is transmitted from the side frames14to the cross members16. Because of this, at the time of a side impact to the vehicle, intrusion of the impactor into the cabin space can be inhibited at an early stage.

Furthermore, in the present embodiment, the exhaust gas pipe28is disposed more inward in the vehicle width direction than the side frames14, so the exhaust gas pipe28can be protected by the side frames14at the time of a side impact to the vehicle.

Furthermore, in the present embodiment, the battery30is disposed on the vehicle upper side of the floor panel18, and the exhaust gas pipe28is disposed on the vehicle lower side of the floor panel18. Furthermore, the battery30and the exhaust gas pipe28are disposed in such a way as to not coincide with each other as seen in a plan view, and distance between the battery30and the exhaust gas pipe28is ensured. For this reason, heat damage to the battery30caused by the exhaust gas pipe28can be reduced.

Second Embodiment

Next, a vehicle70to which a vehicle underbody structure pertaining to a second embodiment has been applied will be described on the basis ofFIG.5andFIG.6. It will be noted that parts that are the same as those in the first embodiment are assigned the same reference signs, and detailed description (also including shared action) will be appropriately omitted. The vehicle70pertaining to the second embodiment differs from the vehicle10pertaining to the first embodiment in that it is a fuel cell vehicle, and hydrogen tanks72are mounted to the vehicle underbody.

As shown in these drawings, the vehicle70has, as a drive source, the traveling motor24in the drive unit20provided in the vehicle front portion. The traveling motor24is driven by optimally separately using electric power supplied from two energy sources, a fuel cell (FC) stack74and a battery76.

Specifically, electric energy and water are produced by a chemical reaction between oxygen and hydrogen taken into the FC stack74. Then, electric power is supplied from the FC stack74to the traveling motor24, and the traveling motor24is driven. It will be noted that some of the electric energy produced by the FC stack74is stored in the battery76, so that it is also possible to supply electric power to the traveling motor24from the battery76by separate use of the FC stack74and the battery76. Furthermore, supply of the hydrogen to the FC stack74is performed from the hydrogen tanks72, which are mounted to the lower side of the floor panel18. It will be noted that the hydrogen tanks72correspond to a “fuel tank” of the disclosure.

As shown inFIG.6, the battery76is disposed on the vehicle upper side of the front portion of the floor panel18as in the first embodiment. The battery76is disposed on the vehicle lower side of the driver's seat44and the front passenger seat46. In the present embodiment, two hydrogen tanks72are mounted in two places on the vehicle rear side of the battery76. The hydrogen tanks72are configured by a first hydrogen tank72A disposed on the vehicle front side and a second hydrogen tank72B disposed on the vehicle rear side of the first hydrogen tank72A. The first hydrogen tank72A and the second hydrogen tank72B are each formed in a hollow closed cylinder shape and disposed in such a way that their longitudinal direction coincides with the vehicle width direction.

The first hydrogen tank72A is disposed on the vehicle lower side of the middle portion of the floor panel18. The first hydrogen tank72A is positioned under the rear seat48of the vehicle70and is installed in such a way as to be accommodated in the space portion42formed on the lower side of the floor panel18. For this reason, the first hydrogen tank72A is disposed on the vehicle upper side of the rockers12as seen in a vehicle side view. The first hydrogen tank72A is disposed on the vehicle width direction inner side of the pair of side frames14of the vehicle70, and the second member16B and the third member16C that configure the cross members16are disposed in this order from the vehicle front side on both vehicle front-rear direction sides of the first hydrogen tank72A. Because of this, the first hydrogen tank72A is surrounded on four sides by the pair of side frames14, the second member16B, and the third member16C as seen in a plan view. It will be noted that the first hydrogen tank72A is secured to the second member16B and the third member16C via tank bands not shown in the drawings.

The second hydrogen tank72B is disposed on the vehicle lower side of the rear portion of the floor panel18. The second hydrogen tank72B is positioned under the luggage compartment49of the vehicle70and is disposed on the vehicle width direction inner side of the right and left pair of rear side members56as seen in a plan view. Furthermore, the fourth member16D that configures the cross members16is disposed on the front side of the second hydrogen tank72B, and the bumper reinforcement54is disposed on the rear side of the second hydrogen tank72B. Because of this, the second hydrogen tank72B is surrounded on four sides by the pair of rear side members56, the fourth member16D, and the bumper reinforcement54as seen in a plan view. It will be noted that the second hydrogen tank72B is secured to the rear side members56and the fourth member16D via tank bands not shown in the drawings.

As shown inFIG.5, the FC stack74that configures the drive unit20is connected to a water discharge pipe78. The water discharge pipe78comprises a cylindrical pipe and has the function of discharging, to the outside of the vehicle, waste water discharged from the FC stack74. It will be noted that the water discharge pipe78corresponds to the “waste pipe” of the disclosure.

The water discharge pipe78is disposed on the lower side of the floor panel18and extends from the drive unit20to the rear end of the vehicle70. Specifically, the part of the water discharge pipe78from its front end portion to its middle portion is disposed in such a way as to extend along the vehicle front-rear direction from the drive unit20, bend outward in the vehicle width direction on the front side of the battery76, and cross in front of the battery76as seen in a plan view. Then, the water discharge pipe78extends in the vehicle rearward direction along the vehicle width direction right side of the battery76, the first hydrogen tank72A, and the second hydrogen tank72B. Furthermore, the water discharge pipe78is disposed more inward in the vehicle width direction than the side frame14on the vehicle width direction right side of the battery76, the first hydrogen tank72A, and the second hydrogen tank72B. It will be noted that the water discharge pipe78may also be disposed between the side frame14and the rocker12and that the water discharge pipe78may also be disposed on the vehicle width direction left side of the battery76, the first hydrogen tank72A, and the second hydrogen tank72B.

Next, the action and effects of the vehicle underbody structure pertaining to the present embodiment will be described.

The configuration of the present embodiment differs from the configuration of the first embodiment in that the hydrogen tanks are mounted instead of the gasoline tank of the first embodiment to the vehicle underbody, but the same action and effects are obtained because it basically follows the configuration of the first embodiment.

Furthermore, in the present embodiment, the four sides of the first hydrogen tank72A are surrounded by the pair of side frames14, the second member16B, and the third member16C as seen in a plan view, so the first hydrogen tank72A can be protected from the load input to the vehicle body at the time of an impact to the vehicle.

Furthermore, in the present embodiment, the four sides of the second hydrogen tank72B are surrounded by the pair of rear side members56, the fourth member16D, and the bumper reinforcement54as seen in a plan view, so the second hydrogen tank72B can be protected from the load input to the vehicle body at the time of an impact to the vehicle.

Supplement to the Embodiments

It will be noted that the disclosure is not limited to the above embodiments.

For example, in the first embodiment, the battery30is disposed on the lower side of the driver's seat44and the front passenger seat46on the vehicle upper side of the floor panel18, but the disclosure is not limited to this. The battery30may also be disposed on the lower side of either one of the driver's seat44or the front passenger seat46. Alternatively, the battery30is not limited to being disposed on the lower side of the driver's seat44and the front passenger seat46and may also be disposed on the front side of the driver's seat and the front passenger seat (at the feet of the driver and the front passenger) on the upper side of the floor panel.

Furthermore, in the first embodiment, the battery30is disposed on the lower side of the driver's seat44and the front passenger seat46, and the gasoline tank26is disposed on the lower side of the rear seat48, but the disclosure is not limited to this. The battery may also be disposed on the upper side of the floor panel and on the lower side of the rear seat, and the gasoline tank may also be disposed on the lower side of the floor panel and on the lower side of the luggage compartment49.

Furthermore, in the second embodiment, two hydrogen tanks72are mounted to the underbody of the vehicle70, but the disclosure is not limited to this, and the number of hydrogen tanks mounted to the vehicle may also be one or may also be three or more.

Furthermore, in the second embodiment, the battery76is disposed on the lower side of the driver's seat44and the front passenger seat46on the vehicle upper side of the floor panel18, but the disclosure is not limited to this. The battery76may also be mounted to the lower side of the rear seat of the vehicle, with one hydrogen tank being mounted to the lower side of the luggage compartment49of the vehicle.