Fuel tank structure

A fuel tank structure for a vehicle using gaseous fuel, has a plurality of cylindrical tank main bodies communicating from one another. The plurality of cylindrical tank main bodies are disposed at a fuel tank mount portion in a state of being adjoined from one another.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a fuel tank structure for use in a vehicle using gaseous fuel such as natural gas.

2. Description of the Related Art

Conventionally, among vehicles using gaseous fuel such as natural gas, there are vehicles on which a large-size fuel tank100is mounted as shown in FIG.16. The fuel tank100is usually configured in a cylindrical shape in order to uniformly disperse the pressure of fuel gas contained therein. Since the diameter of the fuel tank becomes large in order to secure a sufficient capacity, a large space such as a room110is utilized as a place where the fuel tank is mounted.

A partition plate111is provided at the rear side of the fuel tank100and the rear side of the partition plate is used as a practical portion for the trunk room110.

However, since there are many useless spaces at the mounting portion of such cylindrical fuel tank100with a large diameter, there arise problems that the space utilization factor is degraded and the space within the vehicle such as the trunk room110is reduced to a large extent. Further, when the size of the fuel tank100is reduced, there arises a problem that the capacity of the fuel gas inevitably is reduced.

Thus, there is proposed an example (JP-A-2000-219050) wherein the fuel tank100is divided into two tanks each having a relatively small diameter and the two tanks are disposed in a manner that the outer peripheral surface shapes thereof fit to the lower surface shape of a rear seat102. However, such an example is insufficient for the versatility and so is not satisfactory.

SUMMARY OF THE INVENTION

Accordingly, an object of the invention is to provide a fuel tank structure with a rigid structure which can be disposed freely at a mounting portion and can secure a sufficient capacity for fuel gas in a limited space.

In order to solve the aforesaid problems, according to the first aspect of the invention, there is provided a fuel tank structure for a vehicle using gaseous fuel, including: a plurality of cylindrical tank main bodies (for example, tank main bodies301,302,501,502,701,702in embodiments) communicating with one another, the plurality of cylindrical tank main bodies being disposed at a fuel tank mount portion in a state of being adjoined with one another.

According to such a configuration, the plural cylindrical tank main bodies are disposed closely with one another in correspondence with a tank mount portion in a stacked manner and the length thereof is adjusted, whereby the configuration of the fuel tank can be freely fit to the space of the tank mount portion of a vehicle while securing a fuel gas capacity.

The fuel tank structure according to the first aspect, further includes a plate member (for example, plate members321,322,52,721,722in the embodiments) provided so as to cross among the plural cylindrical tank main bodies, the plate member having a communication portion (for example, communication paths341,342,54,741,742in the embodiments) for communicating the respective tank main bodies, wherein the respective tank main bodies are attached to the fuel tank mount portion through the plate member so as to communicate with one another.

According to such a configuration, the respective tank main bodies can be coupled by the plate member and the respective tank main bodies can communicate with one another.

In the fuel tank structure according to the second aspect, the plate member is disposed at an intermediate region between both end portions in a longitudinal direction of the respective tank main bodies.

According to such a configuration, the both end portions of the respective tank main bodies can be changed at their positions and adjusted in their lengths in correspondence with the tank mount portion, whereby the configuration of the fuel tank can be fit more freely to the space of the tank mount portion for a vehicle.

According to the third aspect of the invention, there is provided a fixing structure for a fuel tank for use in a vehicle using gaseous fuel, the fuel tank formed by coupling plural cylindrical tank main bodies (for example, tank main bodies301,302,501,502,701,702in embodiments) so as to be coupled with one another is provided with a plate member (for example, a coupling plate361,362,761,762and a communication plate321,322,52,721,722in the embodiments) for coupling the tank main bodies so as to cross thereamong, whereby the fuel tank is fixed to the tank mount portion of the vehicle through the plate member.

According to such a configuration, the plural tank main bodies can be disposed so as to cope with a mount space for the fuel tank, and the configuration of the fuel tank can be freely fit to the configuration of the tank mount portion for a vehicle. Further, since the fuel tank is fixed to the tank mount portion for the vehicle so as to support the plate member provided to cross among the respective tank main bodies, a shock, vibration etc. applied to the fuel tank is inputted to the plate member in a dispersed manner, so that a load applied to the outer wall of the tank main bodies can be reduced.

In the fuel tank structure of the fourth aspect, a band member (for example, a band25in the embodiments) is attached to the plate member, and the fuel tank is fixed to the tank mount portion through the band member.

According to such a configuration, the fuel tank is fixed to the tank mount portion through the band member attached to the plate member, so that the holding force of the band member and a shock, vibration etc. from the vehicle applied to the fuel tank is inputted to the plate member in a dispersed manner, so that a load applied to the outer wall of the tank main bodies can be further reduced.

According to the fifth aspect of the invention, there is provided a fuel tank structure for a vehicle using gaseous fuel which structure includes a plurality of cylindrical tank main bodies (for example, tank main bodies701,702in an embodiment) respectively disposed within fuel tank mount portions of the vehicle so as to be aligned at their longitudinal direction, and cylindrical tank members (for example, tank members751,752in the embodiment) respectively disposed at space portions (for example, space portions K1, K2in the embodiment) caused at the peripheries of the plurality of tank main bodies so as to be aligned at their longitudinal direction with the tank main bodies, wherein each of the tank members has a diameter smaller than that of the tank main body, and the tank main bodies are respectively coupled with the tank members so as to communicate with one another.

According to such a configuration, the cylindrical tank main bodies can be disposed closely with one another so as to cope with the configuration of the fuel tank mount portion, and the cylindrical tank members each having a small diameter can be respectively disposed so as to fill the space portions caused at the peripheries of the plurality of tank main bodies, whereby the configuration of the fuel tank can be freely fit in a closed state to the configuration of the fuel tank mount portion of the vehicle.

Further, when the length of each of the tank main bodies and the tank members is adjusted, the configuration of the fuel tank can be more freely fit to the configuration of the fuel tank mount portion of the vehicle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a first embodiment of the invention will be explained with reference to the drawings.

FIG. 1is an explanatory side view of a vehicle using natural gas, for example, according to the invention.

As shown in this figure, a first fuel tank21formed by coupling a plurality of tank main bodies301each configured in a cylindrical shape with a small diameter is disposed at the rear side of the seat back4of the rear seat2of a vehicle1. A second fuel tank22formed like the first fuel tank21is disposed beneath the seat main body3of the rear seat2.

A trunk room10at the rear side of the seat back4is partitioned into two portions in the longitudinal direction of the vehicle by a partition plate11and the front side portion is used as a tank mount portion at which the first fuel tank21is mounted.

A supporting frame23coupled to a pair of side frames7,7extended in the longitudinal direction of the vehicle is disposed at the tank mount portion, and the first fuel tank21is fixed on the supporting frame23.

A floor panel5is coupled through a step portion to the rear floor6disposed at the rear side of the step portion. A space between a middle cross member8and a rear cross member9each disposed so as to cross between the side frames7at the lower surface side of the rear floor6is used as the tank mount portion for the second fuel tank22.

The second fuel tank22is sandwiched and fixed between the rear floor6and a pair of bands25,25(band members) which are attached from the lower side of the second fuel tank22.

Incidentally, since this tank mount portion is positioned beneath the vehicle floor (outside of the vehicle room), this tank mount portion is covered by a protector28from the lower side thereof, whereby the second fuel tank22is protected from the tipping, grounding etc. Further, a guard pipe29is disposed over the second fuel tank22so as to cross thereover in the longitudinal direction of the vehicle so that the guard pipe serves to enhance the rigidity of the vehicle body thereby to protect the tank mount portion.

The first fuel tank21is formed in a manner that the plurality of cylindrical tank main bodies301each having a small-diameter and extending in a vehicle width direction, that is, a direction perpendicular to the longitudinal direction of the vehicle are disposed in a zigzag fashion closely with one another. Also, the second fuel tank22is formed in a manner that a plurality of cylindrical tank main bodies302each having a small-diameter and extending in the vehicle width direction are disposed in a zigzag fashion closely with one another.

Each of the tank main bodies301,302is a hollow cylindrical member made of extruded aluminum, for example. In this embodiment, each of the tank main bodies301,302contains therein activated charcoal etc. for absorbing and reserving gaseous fuel therein.

The tank main bodies301communicate with one another through a communication plate321(plate member) described later, and also the tank main bodies302communicate with one another through a communication plate322(plate member) described later. Thus, each of the first fuel tank21and the second fuel tank22is constituted as an absorption type low-pressure gas tank of an integration type. Further, the first fuel tank21and the second fuel tank22communicate with each other to constitute a fuel tank20of the vehicle1.

FIG. 2is a perspective view of the first fuel tank21when seen from the left front side thereof.

As shown in the figure, the first fuel tank21is configured in a manner that the plurality of tank main bodies301stacked in the vertical direction are coupled and fixed to one another in a state of being aligned at their left side end portions thereof (a side shown by an arrow LH in the figure).

Specifically, the communication plate321made of aluminum, for example, is attached at the left side end portions of the tank main bodies301so as to cross thereamong and two coupling plates361,361(plate members) made of aluminum, for example, are attached at two intermediate regions at both end portions of the tank main bodies301so as to cross thereamong, respectively, thereby to join the tank main bodies301with one another.

A communication hole311is formed at the left side end portion of each of the tank main bodies301, and the tank main bodies301communicate with one another through a communication path341(communication portion) formed within the communication plate321.

Further, the extended position of the right side end portion of each of the tank main bodies301is individually changed so as to cope with the vehicle body configuration of the right side wall of the vehicle room thereby to cope with the change in the vehicle width direction of the configuration of the tank mount portion.

The first fuel tank21is mounted in a manner that the communication plate321and a coupling plate361on the right side in the vehicle width direction are supported by the side frames23c,23cof the supporting frame23each constituted in a cross shape.

Stays24a,24c, each formed by subjecting a steel plate to a bending molding process, for example, are fastened at the one end sides thereof by bolts and nuts to the front end portion of the communication plate321and the front end portion of the coupling plate361on the right side in the vehicle width direction, respectively. A bracket24b, having a forwardly protruded bolt attachment portion and formed by subjecting aluminum material to the bending molding process, for example, is joined by a welding process to the front end portion of the coupling plate361provided at the almost center portion in the vehicle width direction. Similarly, stays24d,24e, each formed by subjecting a steel plate to the bending molding process, for example, are fastened at the one end sides thereof by bolts and nuts to the rear end portion of the communication plate321and the rear end portions of the respective coupling plates361, respectively.

The other end sides of these stays24a,24cand the bolt attachment portion of the bracket24bare fastened to the front frame23aof the supporting frame23by means of bolts and nuts, and also the other end sides of these stays24d,24eare fastened to the rear frame23bof the supporting frame23by means of bolts and nuts, whereby the first fuel tank21is fixed on the supporting frame23.

A connector39and a pipe40are provided on the front side end surface (a side shown by an arrow FR in the figure) of the communication plate321thereby to form a communication path with the second fuel tank22.

FIG. 3is a perspective view of the second fuel tank22when seen from the right front side thereof.

As shown in the figure, the second fuel tank22is configured in a manner that the plurality of tank main bodies302stacked in three stages, for example, in the vertical direction are coupled and fixed from one another in a state of being aligned at their right side end portions thereof (a side shown by an arrow RH in the figure).

Specifically, the communication plate322made of aluminum, for example, is attached at the right side end portions of the tank main bodies302so as to cross thereamong and two coupling plates362,362(plate members) made of aluminum, for example, are attached at two intermediate regions at both end portions of the tank main bodies302so as to cross thereamong, respectively, thereby to join the tank main bodies302from one another.

A communication hole312is formed at the right side end portion of each of the tank main bodies302, and the tank main bodies302are communicated from one another through communication paths342(communication portions) formed within the communication plate322.

Further, the extended position of the left side end portion of each of the tank main bodies302is individually changed so as to cope with the change in the vehicle width direction of the adjacent side frame7thereby to cope with the change in the vehicle width direction of the configuration of the tank mount portion.

The outer configuration of each of the lower portions of the front and rear edge portions of the coupling plates362,362is formed in a taper shape expanding upward.

The aforesaid bands25,25are attached to the lower edge portions of the coupling plates362,362, respectively.

The band25is formed by a high tensile steel plate. The bands are bent upward from the lower edge portions of the corresponding coupling plates362so as to follow along the front and rear edge portions thereof. Further, the tip end portions of the bands25are bent in the front and rear directions thereby to form attachment portions25a,25bto be attached to the vehicle body, respectively.

Bolts25A are respectively passed through the attachment portions25a,25bfrom the lower direction thereof, and the bolts25A are fastened to the middle cross member8and the rear cross member9, whereby the second fuel tank22is pushed upward and so pressed against and fixed to the rear floor6.

Guide brackets27a,27b,27care attached to the lower edge portion of each of the coupling plates362in order to stably support the outer peripheral surface of the coupling plate362by the band25.

Each of the coupling plates362and the communication plates322is provided at its upper edge portion with abutment surfaces26abutting against the rear floor6, and each of the abutment surfaces26is provided with a cushion rubber26ato be inserted between the abutment surface and the rear floor6.

A connector39and a pipe40are provided on the front side end surface (a side shown by the arrow FR in the figure) of the communication plate322thereby to form a fuel gas supply path to an engine (not shown). Also, a connector39and a pipe40are also provided on the rear side end surface of the communication plate322thereby to form a communication path with the first fuel tank21.

FIG. 4is a plan view of the second fuel tank22and the peripheral portion thereof.

As shown in the figure, the second fuel tank22is disposed at a position surrounded by a pair of the side frames7,7extending in the longitudinal direction (in the left and right direction inFIG. 4) and the middle cross member8and the rear cross member9each extending in the vehicle width direction (elevational direction in FIG.4). Further, the extended position of the left side end portion of each of the tank main bodies302is individually changed so as to cope with the change in the vehicle width direction of the side frame7thereby to cope with the change of the configuration in the vehicle width direction of the tank mount portion.

The reference numeral29depicts the guard pipe formed in a U-shape and reference numeral12depicts an exhaust unit.

FIG. 5is a sectional diagram along a line V—V in FIG.1.

As shown in the figure, the first fuel tank21is disposed at the inside of a wheelhouse13expanding at the inside in the vehicle width direction. However, the extended position of the right side end portion of each of the tank main bodies301is individually changed so as to cope with the configuration of the right side wall of the vehicle room thereby to cope with the change of the configuration in the vehicle width direction of the tank mount portion.

Next, an explanation will be made as to the internal communication structure of each of the tank main bodies302of the second fuel tank22. Since the communication structure of the first fuel tank21is same as that of the second fuel tank22, the explanation thereof is omitted.

FIG. 6is a sectional diagram along a line VI—VI in FIG.3.

As shown in this figure, a cap38is jointed by a friction stirring welding, for example, to each of the opening portions of the both ends of the tank main body302.

The tank main body302is joined with the entire circumferential periphery of the through hole332of the communication plate322. Also, the tank main body302is entirely or partially joined with the circumferential peripheries of the through holes372,372of the coupling plates362,362.

A pair of the communication holes312,312are provided at the right side end portion of the tank main body302so as to oppose each other. The communication path342is provided at an almost intermediate portion in the thickness direction of the communication plate322so as to correspond to the communication hole312of the tank main body302.

A pair of the guide brackets27a,27aserving as a guide for the band25are fastened by means of bolts and nuts so as to sandwich the lower edge portion of each of the coupling plates362.

Each of the guide brackets27ais formed by a steel plate having been subjected to a press molding, for example. Each of the guide brackets27ais formed along the outer peripheral surface of the lower edge portion of the coupling plate362and is provided with a supporting wall27aA so as to broaden the width of this outer peripheral surface to cope with the width of the band25. Further, the side edge portion of each of the supporting walls27aA is bent toward the lower side (the band25side) to form a supporting wall27aB. A cushion rubber26bis inserted between the band25and the guide brackets27a,27aand the coupling plate362.

Thus, even if a tension is applied to the band25at the time of fixing the first fuel tank21, the band25is prevented from falling from the lower edge portion of the coupling plate362due to the presence of the supporting walls27aA of the respective guide brackets27a. Further, in that case, the band25is prevented from shifting in the vehicle width direction due to the presence of the supporting walls27aB, whereby the coupling plate362of the first fuel tank21can be stably supported.

In this respect, each of the guide brackets27b,27calso has the configuration similar to that of the guide bracket27a. As shown inFIG. 3, since these guide brackets27b,27care equally disposed along the front and rear edge portions from the lower edge portion of the coupling plate362, respectively, even if a tension is applied to the band25, the coupling plate362can be supported stably. Thus, the first fuel tank21can be stably fixed to the tank mount portion beneath the floor of the vehicle1.

FIG. 7is a sectional diagram along a line VII—VII in FIG.6.

As shown in this figure, the respective through holes332are provided so as to be stacked in three stages in a vertical direction. A communication path342is provided between adjacent through holes332,332at each stage of the through holes332so as to pass almost the center portion thereof, at a position extending along the front and rear (left and right inFIG. 5) end surfaces of the communication plate322.

Further, at each of the front and rear end portions of the communication plate322, two upper and lower communication paths352,352are formed so as to cross with the through holes332of the upper and lower stages and the communication path342of the middle stage and further are opened at a corresponding one of the front and rear end surfaces of the communication plate322.

Each of the tank main bodies302corresponding to the upper and lower communication paths352,352among all the tank main bodies302is provided with a communication hole312a. At each of the front and rear end surfaces of the communication plate322, a connector39is screwed to the opening portion of the communication path342of the intermediate stage and blocking plugs41are fixedly secured to the opening portions of the remaining communication paths342and the upper and lower communication paths352, respectively.

According to the aforesaid configuration, the plurality of tank main bodies301closely disposed in a stacked manner are coupled from one another by the coupling plates361and the communication plate321, and also the plurality of tank main bodies302closely disposed in a stacked manner are coupled with one another by the coupling plates362and the communication plates322. Further, the internal portions of the tank main bodies301,302each being blocked communicate by means of the communication plate321,322etc., respectively. Thus, the plurality of tank main bodies301,302are integrated as the single fuel tank20.

The configuration of the fuel tank20can be freely fitted to the configuration of the tank mount portion by adjusting the length to the end portion of each of the tank main bodies301,302and also by adjusting the number of the stacks of the tank bodies. Thus, the tank mount portions within the trunk room10and beneath the rear floor6can be made small while securing a sufficient fuel gas capacity, and the space within the vehicle room such as the trunk room10etc. can be secured sufficiently.

Further, a communication pipe etc. is not protruded from the end surface at the one end side of each of the tank main bodies301,302, and the extended position of the end portion at the other side of each of the tank main bodies can be individually changed, whereby the fuel tank mount portions can be utilized efficiently as the fuel gas containing portion without waste.

Further, the fuel tank20is fixed to the tank mount portion of the vehicle1through the coupling plates361,362and the communication plates321,322, which are provided so as to cross over the respective tank main bodies301,302. Thus, a shock, vibration etc. inputted from the vehicle1is not directly applied to the tank main bodies301,302but inputted to the coupling plates361,362and the communication plates321,322in a dispersed manner. Therefore, a load applied to the respective tank main bodies301,302can be reduced, and hence the light weighting and cost reduction of the fixing structure for the fuel tank can be attained while suppressing the intensity and rigidity of the respective tank main bodies301,302to a required minimum degree.

Further, the second fuel tank22mounted beneath the rear floor6is supported in a manner that each of the coupling plates362provided so as to cross over the respective tank main bodies302is supported so as to be pushed up at outer peripheral surface of the lower edge portion thereof by the band25and the outer peripheral surface of the lower edge portion of the coupling plate362is pushed against the rear floor6, whereby the second fuel tank22is fixed to the tank mount portions.

Thus, the holding force of the band25is not directly applied to the outer walls of the tank main bodies302but inputted to the coupling plate362in a dispersed manner. Therefore, a load applied to each of the tank main bodies302can be reduced, and hence the light weighting and cost reduction of the fixing structure for the fuel tank can be attained while suppressing the intensity and rigidity of the respective tank main bodies301,302to a required minimum degree.

In a modification of the first embodiment, as shown inFIG. 8, the communication plate321may not be provided at the end portion of the tank main bodies301but may be provided at the position where one of the coupling plates361is disposed, and also the communication plate322may not be provided at the end portion of the tank main bodies302but may be provided at the position where one of the coupling plates362is disposed.

According to such a configuration, in the first fuel tank21, the number of the coupling plates361can be reduced from two to one, and the extended position of the left side end portion of each of the tank main bodies301can be individually changed like the right side end portion thereof. Further, in the second fuel tank22, the number of the coupling plates362can be reduced from two to one, and the extended position of the right side end portion of each of the tank main bodies302can be individually changed like the left side end portion thereof.

Accordingly, the number of the parts of the fuel tank20can be reduced and the tank mount portions can be utilized further efficiently without waste as the fuel gas containing portion.

Next, a second embodiment according to the invention will be explained with reference toFIGS. 9 and 10.

In this embodiment, each of the tank main bodies301,302is changed from a cylindrical shape to a multi-cell configuration.

SinceFIG. 9is an explanatory side view corresponding toFIG. 1, portions identical to those ofFIG. 1are referred to by the common symbols, with explanation thereof being omitted.

As shown inFIG. 9, each of the tank main bodies501and the tank main bodies502is formed by extruded aluminum material, for example, of a multi-cell configuration. A plurality of the tank main bodies501are coupled to form the first fuel tank21and a plurality of the tank main bodies502are coupled to form the second fuel tank22.

Next, the inner communication structure of the respective tank main bodies502will be explained. Although the following explanation will be made as to the second fuel tank22as an example, since the inner communication structure of the first fuel tank21is similar to that of the second fuel tank, the explanation thereof will be omitted.

FIG. 10is a sectional diagram along a line X—X in FIG.9.

As shown in the figure, an integration type plate member52formed by extruded aluminum material, for example, and extended across the respective tank main bodies502is joined to the left side end surface of the tank main bodies502. Also, a plate58formed by aluminum, for example, is joined to the right side end surface of the tank main bodies502.

Two coupling plates56,56are fixed through a welding process to the tank main body502so as to cross over the intermediate regions between the both end portions of the tank main body502.

The plate member52is provided at its sectional area with two communication paths54,54(communication portions). These two communication paths54are provided at each of the tank main bodies502so as to extend over two cells502a,502aaligned in a direction perpendicular to the extending direction of the communication paths.

Since a communication hole54ais provided between the communication path54and each of the cells502a, the inner portions of the respective cells502aare integrated for each of the communication paths54. Further, since a notch55is provided at each of partition walls502bof the respective cells502awhich are aligned perpendicular to the communication paths54, the respective communication paths54communicate with one another.

According to the aforesaid configuration, a plurality of the tank main bodies501,502each formed in the multi-cell configuration are integrated as a single fuel tank20. Thus, like the first embodiment, the fuel tank mount portion within the trunk room10and beneath the rear floor6can be reduced and a sufficient space can be secured within the vehicle such as the trunk room10while securing a sufficient fuel gas capacity.

Further, since each of the tank main bodies501,502is formed as the multi-cell configuration, there is no space which is caused when the cylindrical tank main bodies301,302are disposed close to one another, and hence a smaller-sized fuel tank20with the same capacity can be realized. Thus, the tank mount portion can be further miniaturized and so a space for disposing various kinds of devices etc. can be secured.

Further, since the number of the parts can be reduced to a large extent, the cost at the time of an assembling procedure etc. can be reduced.

Next, a third embodiment of the invention will be explained with reference to the drawings.

FIG. 11is a side sectional view of a vehicle using natural gas, for example, according to the invention. SinceFIG. 11is an explanatory side view corresponding toFIG. 1, portions identical to those ofFIG. 1are referred to by the common symbols, with explanation thereof being omitted.

As shown in this figure, a first fuel tank21formed by coupling a plurality of cylindrical tank main bodies701and a plurality of tank members751each having a diameter smaller than that of the tank main body is disposed at the rear side of the seat back4of the rear seat2of a vehicle1. A second fuel tank22formed by coupling a plurality of cylindrical tank main bodies702and a plurality of tank members752each having a diameter smaller than that of the tank main body702is disposed beneath the seat main body3of the rear seat2.

A trunk room10at the rear side of the seat back4is partitioned into two portions in the longitudinal direction of the vehicle by a partition plate11. The front side portion thus partitioned, that is, a space which is sandwiched in the longitudinal direction between the seat back4and the partition plate11and sandwiched in the vertical direction between a rear shelf14and a rear floor6is used as a tank mount portion at which the first fuel tank21is mounted. The tank mount portion is formed to be narrow at its front side upper portion since the seat back4is slanted and the rear shelf14is extended downward so as to support the seat back4.

The first fuel tank21is configured in a manner that the plurality of cylindrical tank main bodies701extending in the vehicle width direction is provided as a major fuel gas containing portion and also the cylindrical tank members751each having a diameter smaller than that of the tank main body701is disposed as another fuel gas containing portion at space portions K1at the peripheries of the respective tank main bodies301, that is, space portions provided at the peripheries of the respective tank main bodies701when the tank main bodies701are disposed at the tank mount portion of the first fuel tank21.

Similarly, the second fuel tank22is configured by the plurality of cylindrical tank main bodies702extending in the vehicle width direction and the cylindrical tank members752each having a diameter smaller than that of the tank main body702disposed at space portions K2at the peripheries of the respective tank main bodies702.

In this respect, each of the tank main bodies701and702is set to have a diameter as large as possible so that the corresponding tank mount portion is divided into the minimum numbers of sections. Further, the diameter of each of the tank members751and752is set so as to correspond to a space portion available when the respective tank main bodies are disposed at the corresponding tank mount portion.

The first fuel tank21is arranged in a manner that the tank main bodies701of two stages and the tank main bodies701of three stages are disposed at the front side and the rear side, respectively, so as not to interfere with the seat back4and the rear shelf14constituting the tank mount portion. Further, in order to set the length of each of the tank main bodies701as long as possible (see FIG.15), each of the tank main bodies701is disposed at positions closer to the front side of the tank mount portion so as to avoid a trunk hinge15provided at the rear side upper portion of the tank mount portion.

The plurality of small-diameter tank members751are respectively disposed at the space portions K1at the peripheries of the tank main bodies701so as to fill up the spaces. The tank members751are also disposed so as to avoid the rear shelf14at the front side upper portion of the tank mount portion. At the rear side upper portion of the tank mount portion, the extending positions of the end portions of the tank members751are adjusted so as not to interfere with the trunk hinge15(see FIG.15).

In the second fuel tank22, the four tank main bodies702are disposed almost with a constant interval in the longitudinal direction within the tank mount portion and the tank members752are disposed at the space portions K2at the peripheries of the respective tank main bodies702. Each of the tank main bodies702and the tank members752is adjusted at the extended position of the end portions thereof so as to cope with the change of the tank mount portion in the vehicle width direction (see FIG.14).

Each of the tank main bodies701,702and the tank members751,752is a hollow cylindrical member made of extruded aluminum, for example. In this embodiment, each of the tank main bodies701,702and the tank members751,752contains therein activated charcoal etc. for absorbing and reserving gaseous fuel therein and is closed at the both ends.

The tank main bodies701and the tank members751of the first fuel tank21communicate with one another through a communication plate721(plate member) described later, and the tank main bodies702and the tank members752of the second fuel tank22communicate with one another through a communication plate722(plate member) described later. Thus, each of the first fuel tank21and the second fuel tank22is constituted as an absorption type low-pressure gas tank of an integration type. Further, the first fuel tank21and the second fuel tank22communicate with each other to constitute a fuel tank20of the vehicle1.

FIG. 12is a perspective view of the second fuel tank22when seen from the right front side thereof.

As shown in the figure, the second fuel tank22is configured in a manner that the plurality of tank main bodies702and the tank members752are coupled and fixed to one another in a state of being aligned at their right side end portions thereof (a side shown by an arrow RH in the figure).

Specifically, the communication plate722made of aluminum, for example, is attached at the right side end portions of the tank main bodies702and the tank members752so as to cross thereamong thereby to combine the tank main bodies702and the tank members752with the entire circumferential peripheries of the respective through holes of the communication plate722.

Coupling plates762,762(plate members) made of aluminum, for example, are attached at two intermediate regions at both end portions of the tank main bodies302and the tank members752so as to cross thereamong, respectively, thereby to combine the tank main bodies702and the tank members752with the entire circumferential peripheries of the respective through holes of the coupling plates762,762.

A communication hole712is formed at the right side end portion of each of the tank main bodies702and the tank members752, and the tank main bodies702and the tank members752communicate with one another through a communication path742formed within the communication plate722. Further, the length to the left side end portion of each of the tank main bodies702and the tank members752is determined so as to fit the space within which the second fuel tank22is disposed.

FIG. 13is a perspective view of the first fuel tank21when seen from the left front side thereof.

As shown in the figure, the first fuel tank21is configured in a manner that the plurality of tank main bodies701and the tank members751are coupled and fixed to one another in a state of being aligned at their right side end portions thereof (a side shown by an arrow LH in the figure).

Specifically, the communication plate721made of aluminum, for example, is attached at the left side end portions of the tank main bodies701and the tank members751so as to cross thereamong thereby to combine the tank main bodies701and the tank members751with the entire circumferential peripheries of the respective through holes of the communication plate721.

Coupling plates761,761(plate members) made of aluminum, for example, are attached at two intermediate regions at the both end portions of the tank main bodies701and the tank members751so as to cross thereamong, respectively, thereby to combine the tank main bodies701and the tank members751with the entire circumferential peripheries of the respective through holes of the coupling plates761,761.

A communication hole711is formed at the left side end portion of each of the tank main bodies701and the tank members751, and the tank main bodies701and the tank members751communicate with one another through a communication path741formed within the communication plate721. Further, the length to the right side end portion of each of the tank main bodies701and the tank members751is determined so as to fit the space within which the first fuel tank21is disposed.

FIG. 14is a plan view of the second fuel tank22and the peripheral portion thereof.

As shown in the figure, the second fuel tank22is disposed at a position surrounded by a pair of the side frames7,7extending in the longitudinal direction (in the left and right direction inFIG. 14) and the middle cross member8and the rear cross member9each extending in the vehicle width direction (elevational direction in FIG.14).

Here, the second fuel tank22is arranged in a manner that the extended position of the left side end portion of each of the tank main bodies702is individually changed so as to cope with a wheelhouse13and the change in the vehicle width direction of the side frame7so that the length of the tank main body702serving as the major fuel gas containing portion is made as long as possible. Further, in order to use the space portions K2at the peripheries of the tank main bodies702without waste as the fuel gas containing portion, the extended position of the left side end portion of each of the tank members752is individually changed so as to cope with the wheelhouse13and the change in the vehicle width direction of the side frame7so that the length of the tank member752is made as long as possible.

FIG. 15is a rear side view of the first fuel tank21and the peripheral portion thereof.

As shown in the figure, the first fuel tank21is disposed at the inside of the wheelhouse13expanding at the inside in the vehicle width direction.

Here, the first fuel tank21is arranged in a manner that the extended position of the right side end portion of each of the tank main bodies701is individually changed so as to cope with the vehicle body configuration of the right side wall of the vehicle room so that the length of the tank main body701serving as the major fuel gas containing portion is made as long as possible. Further, in order to use the space portions K1at the peripheries of the tank main bodies701without waste as the fuel gas containing portion, the extended position of the right side end portion of each of the tank members751is individually changed so as to cope with the trunk hinge15and the vehicle body configuration of the right side wall of the vehicle room so that the length of the tank member751is made as long as possible.

According to the aforesaid configuration, the plurality of tank main bodies701,702and the plurality of tank members751,752disposed densely are coupled and fixed to one another so as not to move relative to the plates761,762and the communication plates721,722, respectively. Further, since the tank main bodies701,702and the tank members751,752communicate with the communication plates721,722etc., the plurality of tank main bodies701,702and the plurality of tank members751,752are integrated as the single fuel tank20.

Since the extended position of the end portion of each of the tank main bodies701,702and the tank members751,752is individually changed and how to arrange these bodies and members and the numbers thereof to be arranged is adjusted, the configuration of the fuel tank can be freely adapted to the configuration of the fuel tank mount portion. Thus, the fuel tank mount portion can be used as the fuel gas containing portion without waste. Therefore, the fuel tank mount portion within the trunk room10and beneath the rear floor6can be reduced while securing a sufficient fuel gas capacity, and the space within the vehicle room such as the trunk room10etc. can be secured sufficiently.

Further, when the tank main bodies701,702and the tank members751,752are fixed rigidly, the intensity and the rigidity of the first fuel tank21and the second fuel tank22can be enhanced.

Particularly, since the outer diameter of each of the tank main bodies701,702is set to be as large as possible, the rigidity of the coupling portions between the communication plates721,722and the coupling plates761,762is enhanced. Further, in the case where a force is applied to the first fuel tank21and the second fuel tank22in a twist direction, the stress is also dispersed to the tank members751,752disposed at the peripheries of the tank main bodies701,702, whereby the torsional rigidity of the first fuel tank21and the second fuel tank22can be enhanced. Furthermore, the compression intensity in the longitudinal direction of these tanks can be enhanced.

In a modification of the third embodiment, the length of one end portion of each of the tank main bodies701,702and the tank members751,752may be determined in accordance with the space where the first and second fuel tanks are disposed in the same manner as the other end potions thereof instead of aligning the one end portions thereof.

According to such a configuration, in the first fuel tank21, the extended position of the left side end portion of each of the tank main bodies701can be individually changed like the right side end portions thereof. Also, in the second fuel tank22, the extended position of the right side end portion of each of the tank main bodies702can be individually changed like the left side end portions thereof. Thus, the fuel tank mount portion can be utilized further efficiently as the fuel gas containing portion without waste.

Incidentally, the invention is not limited to the aforesaid embodiment, and the respective numbers and the sizes etc. of the tank main bodies301,302,501,502,701,702and the tank members751,752can be suitably changed so as to cope with a vehicle, for example.

Further, although the aforesaid embodiment is configured as an absorption type low-pressure gas tank, the gas tank20according to the invention may be configured as a normal low-pressure gas tank containing no adsorbent such as activated charcoal etc.

Furthermore, the gas tank according to the invention may be configured as an absorption type high-pressure gas tank or a normal high-pressure gas tank containing no adsorbent. In this case, the material of the tank main bodies is preferably changed from aluminum to rigid material such as stainless steel.

Furthermore, the invention is applicable not only to a vehicle using natural gas but also to vehicles using gaseous fuel such as a fuel cell powered vehicle.