Hybrid lean vehicle

Abstract

[Problem] To provide a hybrid lean vehicle that comprises an engine, a power storage, and a fuel tank and that suppresses variation in the position of the center of gravity due to fuel consumption while ensuring maneuverability. [Solution] A hybrid lean vehicle comprises: an engine; a drive motor; a drive wheel driven by the engine and the drive motor; a power storage for supplying power to the drive motor; and a fuel tank for supplying fuel to the engine. When the lean vehicle is in an upright state, the uppermost end of the fuel tank is located at a position higher than the lowermost end of the power storage provided above the engine, and the lowermost end of the fuel tank is located at a position lower than the lowermost end of the power storage.

Description

Hybrid lean vehicles

[0001] This disclosure relates to a hybrid lean vehicle comprising an engine, a drive motor, drive wheels driven by them, a power storage device that supplies power to the drive motor, and a fuel tank that supplies fuel to the engine.

[0002] [Power Storage Layout in Hybrid Lean Vehicles] A lean vehicle (Italian: veicolo inclinabile) is a vehicle designed to tilt inward when the vehicle is in motion, especially when turning. Lean vehicles have a lighter and more compact body structure than automobiles, and the placement of power storage (e.g., battery) has a significant impact on the vehicle's characteristics. In particular, since power storage such as batteries is heavy, its mounting position affects the vehicle's weight balance and behavior. In automobiles, it is common to place power storage in the lower part of the body, which offers relatively more flexibility, but in lean vehicles, placement must be tailored to the size of the lean vehicle within the limited wheelbase and body width. A challenge unique to lean vehicles is the leaning characteristic during turning, which is the characteristic of the vehicle body tilting when cornering. When the rider is cornering, it is necessary to adjust the balance between the centrifugal force acting on the center of gravity and gravity. In this case, the mounting position of the power storage significantly affects the center of gravity, so it is necessary to position it in a way that matches the vehicle's tilt characteristics during cornering. Furthermore, the weight of the power storage also affects the suspension behavior and pitching characteristics (longitudinal sway characteristics), so it is important to consider the front-to-rear weight distribution when positioning it. In addition, in lean vehicles, it is necessary to efficiently position major components such as the engine, motor, and power storage within the limited space of the vehicle body. Thus, the layout of power storage in lean vehicles must satisfy a wide range of requirements, including weight balance and maintainability, within the limited space of the vehicle body. Therefore, positioning power storage that is appropriate for the size of a lean vehicle and fully considers the characteristics of a lean vehicle is a technical challenge in the design of hybrid lean vehicles. [Commercially available hybrid lean vehicles] In lean vehicles, the mounting position of the power storage significantly affects the center of gravity, so it is necessary to position it in a way that matches the vehicle's tilt characteristics during cornering.Non-patent document 1 proposes that, while maintaining the conventional fuel tank placement on the upper part of the main frame, similar to conventional engine-lean vehicles, a battery for power storage is newly positioned above the rear wheels. Referring to non-patent documents 1 and 2, we compare currently available hybrid-lean vehicles with vehicles equipped with engines that produce equivalent output and torque. These vehicles have equivalent maximum system output (approximately 50 kW) and maximum system torque (approximately 60 N・m), as well as equivalent ground clearance (130 mm) and seat height (approximately 790 mm). Furthermore, the fuel tank capacity is almost identical for both vehicles, approximately 14-15 L. However, the hybrid-lean vehicle's weight increases by approximately 34 kg due to the addition of power storage and motors. Additionally, the wheelbase is extended by approximately 125 mm to accommodate these components. (See Figure 6: Comparison table of specifications for hybrid-lean and engine-lean vehicles).

[0003] Kawasaki Ninja 7 Hybrid | Change the Game | New Generation Motorcycle URL: https: / / www.kawasaki-motors.com / ja-jp / motorcycle / hybrid-and-electric / hev / ninja-7-hybrid Model Comparison | Motorcycle Hybrid-And-Electric Comparison of Ninja 7 Hybrid and Ninja 650 URL: https: / / www.kawasaki-motors.com / ja-jp / purchase-tools / compare-vehicles / motorcycle / hybrid-and-electric

[0004] This extension of the wheelbase increases the minimum turning radius to 3.4 m, which may affect maneuverability in urban areas compared to the 2.8 m of a vehicle equipped only with an engine. This can be cited as an example of the problems brought about by the installation of a hybrid system in a lean vehicle, particularly the arrangement of power storage. The method of extending the wheelbase to obtain equivalent output characteristics suggests that there is room for further technical improvement in the original characteristic of high maneuverability of lean vehicles compared to automobiles.

[0005] It is an object of the present invention to provide a hybrid lean vehicle with high maneuverability, which has a power storage layout different from that of the hybrid lean vehicle described in the background art.

[0006] [Effects of one aspect of this disclosure] (1) In one aspect of this disclosure, by taking into account the characteristics of each heavy component, such as the engine, power storage, and fuel tank, and by devising their respective arrangements, it is possible to effectively suppress the variation in center of gravity position (VCGP) during the operation unique to lean vehicles. Generally, a lean vehicle, that is, a vehicle that tilts its body when cornering, has a length that is long in the longitudinal direction, short in the lateral direction, and an intermediate size in the vertical direction. The technical concept of one aspect of this disclosure is to utilize the longitudinal and lateral directions while focusing on the vertical direction in accordance with the characteristics of each heavy component, such as the engine, power storage, and fuel tank. The core of the technical concept of one aspect of this disclosure lies in combining the shape characteristics of a lean vehicle with the arrangement relationship of heavy components. Specifically, by defining the vertical positional relationship between the fuel tank, which is a variable-weight component whose weight changes depending on the usage state, and the engine and power storage, which are fixed-weight components whose weight does not change or changes less depending on the usage state compared to variable-weight components, design flexibility in other directions is ensured. Specifically, the engine and power storage are fixed-weight components whose weight basically does not change during use, and they are fixedly positioned within the vehicle. On the other hand, although the fuel tank is a heavy object, it is a variable-weight component whose weight decreases as fuel is consumed during use. In one aspect of this disclosure, the lowest end of the fuel tank is positioned lower than the lowest end of the power storage, thereby obtaining the following effect. According to one aspect of this disclosure, in the vertical direction of the vehicle, at least a portion of the fuel tank is located between the engine and the power storage. When the fuel tank is full, the fuel tank is a heavy object and a portion of it is located between the engine and the power storage, but as fuel is consumed, the weight at that position gradually decreases. However, because the engine and power storage, which do not change in weight, are located in fixed positions, vertical changes in the center of gravity due to fuel consumption are suppressed.This configuration enables the placement of the fuel tank, which is a variable weight object, between predetermined weight objects in the vertical direction, thereby forming a mechanism that structurally suppresses fluctuations in the center of gravity. This configuration makes it possible to minimize vertical fluctuations in the vehicle's center of gravity regardless of the remaining fuel level. Furthermore, since the engine and power storage do not change weight during use, changes in the center of gravity are suppressed, and the fluctuations in the center of gravity caused by the lighter fuel tank are compensated for by the engine and power storage. Lean vehicles have the characteristic of leaning their body when cornering, so the center of gravity affects the handling characteristics. One aspect of this disclosure can suppress the impact on handling characteristics by suppressing fluctuations in the center of gravity due to fuel consumption. In this way, by understanding the characteristics of the heavy objects, the engine, power storage, and fuel tank, and devising their arrangement relationships, it is possible to suppress the center of gravity fluctuations unique to lean vehicles. Furthermore, in one aspect of this disclosure, the engine and power storage have a low degree of design freedom for their external shape due to functional constraints and are fixed-shape components. On the other hand, a fuel tank, being a liquid storage component, is a flexible-shape component that can be molded into complex shapes by utilizing dead space, i.e., unused space created by the shape constraints of other components, compared to a fixed-shape heavy object. In addition, in one aspect of this disclosure, at least a portion of the fuel tank is located between the engine and power storage in the vertical direction of the vehicle. Both of these features make it possible to provide a lean vehicle with a high degree of freedom in wheelbase design and good maneuverability. One aspect of this disclosure is based on the fundamental technical idea of ​​suppressing fluctuations in the center of gravity by defining the arrangement relationship of heavy objects in the vertical direction, and as a result provides a solution that takes advantage of the structural characteristics of a lean vehicle, ensuring design freedom in the longitudinal and lateral directions. [Effects of other aspects of this disclosure] (2) In other aspects of this disclosure, the following effects can be obtained by forming the fuel tank asymmetrically in a front view of the vehicle. Lean vehicles are generally most constrained in lateral dimensions due to their structure.In the left-right direction, where constraints are greatest, an asymmetrical shape for the fuel tank makes it possible to maximize the use of the limited space. In particular, when combined with the vertical arrangement (where the top of the fuel tank is higher than the bottom of the power storage, and the bottom of the fuel tank is lower than the bottom of the power storage), the following effects can be obtained. Firstly, by adopting an asymmetrical shape in the left-right direction, where constraints are greatest, it is possible to secure the necessary fuel capacity while avoiding interference with certain heavy objects such as the engine and power storage. The adoption of this asymmetrical shape, combined with the vertical arrangement freedom mentioned above, greatly improves the design freedom in the limited vehicle space. Secondly, by combining this left-right asymmetrical shape with the vertical arrangement, it is possible to suppress the change in the center of gravity due to fuel movement when tilting, that is, the change in the center of gravity caused by the fuel shifting to one side when a lean vehicle is tilted, while maintaining the effect of suppressing the vertical center of gravity position change. Thus, the left-right asymmetrical shape of the fuel tank improves the design freedom in the left-right direction, where constraints are greatest in lean vehicles, while complementing the effect of suppressing the vertical center of gravity position change. These two features improve the design freedom of the wheelbase. As a result, it becomes possible to arrange heavy objects in a limited vehicle space and to achieve the excellent maneuverability of a lean vehicle. For example, by achieving a short wheelbase, good handling in city driving can be obtained. [Effects of other embodiments of the present disclosure] (3) In other embodiments of the present disclosure, the following effects can be obtained by arranging at least a portion of the fuel tank in at least one direction, either to the right or to the left, in the side region of the power storage located above the engine. In a lean vehicle, the power storage is generally a heavy object with a high degree of freedom in shape. In this embodiment, the following effects can be obtained by effectively utilizing the side region of this power storage. Firstly, by arranging the fuel tank on the side of the power storage while maintaining the vertical arrangement configuration (the uppermost end of the fuel tank is higher than the lowest end of the power storage, and the lowest end of the fuel tank is lower than the lowest end of the power storage), it becomes possible to distribute the heavy objects in the longitudinal direction. This improves the design freedom in the longitudinal direction.Secondly, by positioning the fuel tank to the side of the power storage, the fuel tank's high degree of design freedom can be utilized to efficiently use the limited space around the power storage. This contributes to miniaturization of the vehicle while maintaining the effect of suppressing fluctuations in the vertical center of gravity. Thus, this embodiment improves the design freedom in the longitudinal direction while maintaining the basic effect of suppressing fluctuations in the vertical center of gravity. Both of these features improve the design freedom of the wheelbase, and as a result, it becomes possible to achieve compact vehicle packaging and excellent maneuverability. For example, by achieving a short wheelbase, it is possible to reduce the minimum turning radius and improve maneuverability in city driving. [Effects of other embodiments of this disclosure] (4) In other embodiments of this disclosure, the fuel lid of the fuel tank can be positioned to the right or left in the peripheral area of ​​the power storage located above the engine, thereby obtaining the following effects. In lean vehicles, the fuel lid needs to be accessed when refueling, and its position greatly affects workability. In this embodiment, the following effects can be obtained by placing the fuel lid in the area surrounding the power storage. Firstly, it is possible to ensure access to the fuel filler while maintaining the vertical arrangement configuration (the uppermost point of the fuel tank is higher than the lowest point of the power storage, and the lowest point of the fuel tank is lower than the lowest point of the power storage). This has the effect of improving practicality while appropriately maintaining the center of gravity of the fuel tank. Secondly, by placing the fuel lid in the area surrounding the power storage, the fuel supply path can be simplified. This increases the degree of freedom in the shape of the fuel tank and increases the degree of freedom in placement within the limited vehicle space. In particular, by efficiently arranging the fuel tank in accordance with the vehicle structure while ensuring convenience during refueling, the design freedom in the longitudinal direction is improved. Thus, this embodiment maintains the basic effect of suppressing fluctuations in the center of gravity in the vertical direction while increasing the design freedom in the longitudinal direction and practical convenience.These two features increase the design flexibility of the wheelbase, making it possible to achieve both maintainability and excellent maneuverability. For example, it is possible to achieve a short wheelbase while providing the practical value of easy refueling. [Effects of other embodiments of the disclosure] (5) In other embodiments of the disclosure, the following effects can be obtained by placing the power storage on the centerline of the vehicle body and the fuel lid to the right or left of the peripheral area of ​​the power storage. In lean vehicles, the power storage is heavy and its placement has a significant impact on the vehicle's behavior. In this embodiment, the following effects can be obtained by placing the power storage on the centerline of the vehicle body and the fuel lid in its peripheral area. Firstly, by placing the heavy power storage on the centerline of the vehicle body, it becomes easier to achieve lateral weight balance. In addition to this arrangement, the vertical arrangement (placing the top of the fuel tank above the bottom of the power storage, and the bottom of the fuel tank below the bottom of the power storage) enhances the effect of suppressing fluctuations in the center of gravity. Secondly, by placing the power storage on the vehicle's centerline, a clear space is secured in the surrounding area for installing the fuel lid. This improves the design freedom of the fuel supply route and increases the freedom of the vehicle layout in the front-rear direction. In particular, it becomes possible to place the fuel tank in a position suitable for the vehicle structure while ensuring convenience during refueling. Thus, this embodiment makes it easier to balance the weight on the left and right sides by centrally placing the power storage, and also enables the placement of the fuel lid in the surrounding area. These features improve the design freedom of the wheelbase, making it possible to achieve both suppression of fluctuations in the center of gravity and excellent maneuverability. Specifically, it is possible to suppress fluctuations in the center of gravity during lean driving while maintaining a short wheelbase and ensuring ease of refueling. [Effects of other embodiments of the present disclosure] (6) In other embodiments of the present disclosure, at least a portion of the power storage is located between the control device that controls the drive motor and the fuel tank in the front view of the vehicle.In lean vehicles, power storage is heavy, and its placement significantly affects the vehicle's behavior. Therefore, this embodiment provides the following benefits. Firstly, by placing the heavy power storage between the control unit and the fuel tank in a front view, it becomes easier to achieve vertical and lateral weight balance. This further enhances the suppression of center of gravity fluctuations caused by the vertical placement configuration (where the top of the fuel tank is higher than the bottom of the power storage, and the bottom of the fuel tank is lower than the bottom of the power storage). Secondly, by placing the power storage between the control unit and the fuel tank in a front view, the distance between the control unit and the motor can be shortened. This improves the reliability of the electrical connection between the control unit and the motor, and increases the freedom of the vehicle layout in the longitudinal direction. In particular, it becomes possible to position the fuel tank in accordance with the vehicle structure while ensuring controllability. Thus, this embodiment achieves both the ease of weight balance by placing the power storage between the control unit and the fuel tank in a front view and the efficiency of the wiring route from the control unit to the motor. Both of these features improve the design freedom of the wheelbase, and as a result, it becomes possible to achieve excellent maneuverability while suppressing center of gravity fluctuations. For example, it is possible to achieve a short wheelbase while simultaneously suppressing changes in the center of gravity position during lean driving and improving controllability. [Effects of other embodiments of the present disclosure] (7) In other embodiments of the present disclosure, the following effects can be obtained by arranging at least a portion of the fuel tank so as to overlap with at least a portion of the damper (shock-absorbing device) in a view of the vehicle body from side to side. In lean vehicles, the damper deforms, so it is necessary to secure space around it to allow for deformation. In this embodiment, by utilizing the design freedom of the shape of the fuel tank and arranging the fuel tank so as to overlap with the damper in a view of the vehicle body from side to side, the following effects can be obtained. Firstly, by arranging the fuel tank so as to overlap with the damper in a view of the vehicle body from side to side, the space around the damper can be effectively utilized. This further enhances the effect of suppressing changes in the center of gravity position due to the arrangement configuration in the vertical direction (arrangement in which the uppermost end of the fuel tank is higher than the lowest end of the power storage, and the lowest end of the fuel tank is lower than the lowest end of the power storage).Secondly, by positioning the fuel tank so that it overlaps with the shock absorber when viewed from the left and right, space in the longitudinal direction of the vehicle body can be secured. This improves the design freedom in the placement of the fuel tank and shock absorber, and increases the freedom of the vehicle layout in the longitudinal direction. In particular, it becomes possible to position the fuel tank in accordance with the vehicle structure while ensuring the performance of the shock absorber. Thus, this embodiment achieves both effective use of space through the overlapping arrangement of the fuel tank and shock absorber and securing space in the longitudinal direction of the vehicle body. Due to both of these features, the design freedom of the wheelbase is improved, and as a result, it becomes possible to achieve excellent maneuverability while suppressing fluctuations in the center of gravity. For example, it is possible to achieve a short wheelbase while simultaneously suppressing fluctuations in the center of gravity during lean driving and ensuring the performance of the shock absorber. [Effects of other embodiments of this disclosure] (8) In other embodiments of this disclosure, the following effects can be obtained by positioning the uppermost end of the fuel tank so that it is located in front of the vehicle than its lowermost end. In a lean vehicle, the fuel tank is a component that affects the space in the longitudinal direction of the vehicle. Compared to conventional fuel tanks that are long in the front-to-rear direction, this embodiment provides the following advantages by positioning the upper end of the fuel tank forward of its lower end. Firstly, by positioning the upper end of the fuel tank forward of its lower end, the space at the rear of the vehicle can be effectively utilized. This further enhances the effect of suppressing fluctuations in the center of gravity caused by the vertical arrangement (the upper end of the fuel tank is higher than the lower end of the power storage, and the lower end of the fuel tank is lower than the lower end of the power storage). Secondly, by positioning the upper end of the fuel tank forward of its lower end, the fuel tank can be efficiently positioned along the shape of the vehicle. This improves the design freedom in fuel tank placement compared to long fuel tanks in the front-to-rear direction, and increases the freedom of vehicle layout in the front-to-rear direction. In particular, it becomes possible to position the fuel tank in accordance with the vehicle structure while improving its conformity to the shape of the vehicle. Thus, this embodiment achieves both effective utilization of space at the rear of the vehicle and fuel tank placement that conforms to the shape of the vehicle.These two features increase the design flexibility of the wheelbase, making it possible to achieve excellent maneuverability while suppressing fluctuations in the center of gravity. For example, it is possible to achieve a short wheelbase while simultaneously suppressing fluctuations in the center of gravity during lean driving and improving the arrangement efficiency of the fuel tank. [Upright state of a leaning vehicle] The upright state means that the body of a leaning vehicle is not tilted relative to the vertical line, and the line connecting the contact points of the left and right tires is parallel to the horizontal plane. Specifically, it refers to a posture in which the center line of the vehicle frame is parallel to the vertical line, and the plane containing the contact points of the left and right wheels is horizontal. This state corresponds to, for example, the posture when a leaning vehicle is parked on a flat horizontal surface and balanced on both feet. [Leaning vehicle] A leaning vehicle (Italian: veicolo inclinabile) is a vehicle designed so that the body tilts inward towards the curve when the vehicle is driving, especially when turning. This lean vehicle can be implemented as a straddle-type vehicle (veicolo tipo straddle), where the rider straddles the vehicle, or as a sit-in type vehicle (veicolo tipo seduto), where the rider is seated while driving. Typical examples include motorcycles (motocicletta), three-wheeled vehicles (veicolo a tre ruote), and scooters (scooter). In the case of three-wheeled vehicles, either a two-front-wheel type (tipo a due ruote anteriori) or a two-rear-wheel type (tipo a due ruote posteriori) configuration is possible. This technology is particularly effective in straddle-type vehicles, but it can also be applied to sit-in type vehicles.

[0007] In one aspect of this disclosure, at least a portion of the fuel tank is located between the engine and the power storage in the vertical direction of the vehicle. Both of these features allow for greater design freedom of the wheelbase and enable the provision of a lean vehicle with good maneuverability. Thus, one aspect of this disclosure provides a solution that takes advantage of the structural characteristics of a lean vehicle, based on the fundamental technical idea of ​​suppressing fluctuations in the center of gravity by defining the arrangement of heavy objects in the vertical direction, while also ensuring design freedom in the longitudinal and lateral directions.

[0008] Right side view and left side view of a hybrid lean vehicle according to one aspect of this disclosure Right side view, left side view, front view and top view of a hybrid lean vehicle according to another aspect of this disclosure Right side view, left side view, front view and top view of a hybrid lean vehicle according to another aspect of this disclosure Right side view, left side view, front view and top view of a hybrid lean vehicle according to another aspect of this disclosure Top view of a hybrid lean vehicle according to another aspect of this disclosure Comparison table of specifications of hybrid lean vehicles and engine lean vehicles

[0009] [Summary of the Disclosure] A lean vehicle 1 in one aspect of the Disclosure has a structure that tilts the vehicle body when turning by front wheels 10 positioned on the left and right sides of the vehicle. This vehicle employs a hybrid structure equipped with an engine 2 and a drive motor 3 as a drive source. The drive motor 3 is positioned on the same side of the vehicle as the engine 2, and both are appropriately positioned considering the center of gravity G. Power storage 4 is located on the upper part of the vehicle body to supply power to the drive motor 3, and its lowest end is indicated as BEPS. Fuel tank 5 is located on the upper part of the vehicle body near the seat rail 8, and its uppermost and lowermost ends are defined as TEFT and BEFT, respectively. Fuel is supplied via a fuel lid 6. Frame 7 functions as the vehicle body skeleton that supports these components. Drive wheels 9 are attached to the vehicle body via a rear swing arm assembly 11 and transmit power from the engine 2 and drive motor 3 to the road surface. The front wheels 10 are responsible for steering the vehicle and also function as part of the lean mechanism when turning. Regarding the arrangement of the drive motor 3, its lowest end is indicated as BETM and its uppermost end as TETM, and the positional relationship in the height direction is determined considering the vehicle's center of gravity G. The control device 13 performs coordinated control of the engine 2 and the drive motor 3 to realize power distribution according to the driving conditions. In addition, the shock absorber 12 mitigates shocks from the road surface. [One aspect of the present disclosure] Figure 1 shows the right side view (R) and the left side view (L) of a hybrid lean vehicle 1 according to the first aspect of the present disclosure. The hybrid lean vehicle 1 of this embodiment includes an engine 2, a drive motor 3, drive wheels 9 driven by them, a power storage 4 that supplies power to the drive motor 3, and a fuel tank 5 that supplies fuel to the engine 2. The engine 2 generates main power as an internal combustion engine, and the drive motor 3 generates auxiliary power as an electric motor. These powers are transmitted to the drive wheels 9 via the transmission, and this transmitted power becomes the propulsion force of the vehicle. The power storage 4 is an energy storage device such as a lithium-ion battery or capacitor, and supplies the power necessary to operate the drive motor 3. The fuel tank 5 stores the fuel necessary to operate the engine 2.When the lean vehicle 1 is in an upright position, the uppermost end (TEFT) of the fuel tank 5 is positioned higher than the lowest end (BEPS) of the power storage 4 located above the engine 2, and the lowest end (BEFT) of the fuel tank 5 is positioned lower than the lowest end (BEPS) of the power storage 4. By arranging a predetermined weight (power storage 4) and a variable weight (fuel tank 5) in this way, fluctuations in the center of gravity (G) due to fuel consumption are suppressed. [Supplementary explanation of one aspect of the present disclosure] As shown in the right side view (R) and left side view (L) of Figure 1, the drive motor 3 and the engine 2 have the following characteristic positional relationship. The uppermost end (TETM) and lowest end (BETM) of the drive motor 3 are set lower than the uppermost end of the engine 2. This allows for efficient power transmission to the drive wheels 9 while avoiding interference with the power storage 4 located above the engine 2. This arrangement, when combined with the positional relationship of the fuel tank 5 in one aspect of this disclosure (where the uppermost TEFT of the fuel tank 5 is higher than the lowest BEPS of the power storage 4, and the lowest BEFT of the fuel tank 5 is lower than the lowest BEPS of the power storage 4), produces the following synergistic effects. Firstly, by positioning the drive motor 3 above the transmission of the engine 2, the fuel tank 5 can effectively utilize the space formed between the drive motor 3 and the power storage 4. Furthermore, by positioning the drive motor 3 above the transmission of the engine 2, the fuel tank 5 can effectively utilize the space formed around the drive motor 3 between the engine 2 and the power storage 4. As a result, the fuel tank 5 can secure the necessary capacity while maintaining its vertical positional relationship with the power storage 4. Secondly, this arrangement allows for the placement of the heavy components of the fuel tank 5, power storage 4, engine 2, and drive motor 3 while ensuring the rigidity of the vehicle body structure composed of the seat rails 8 and the frame 7. This achieves both efficient power transmission to the drive wheels 9 via the rear swing arm assembly 11 and vehicle maneuverability. [Second aspect of the present disclosure] Figure 2 shows a second aspect of the present disclosure. In this embodiment, as shown in the front view (F) of Figure 2, the fuel tank 5 is formed asymmetrically.The fuel tank 5 is a container for storing liquid fuel, and its asymmetrical shape ensures the necessary capacity while avoiding interference with fixed-shape components such as the engine 2 and power storage 4. This asymmetrical structure efficiently utilizes the limited space of the vehicle body. [Third aspect of the disclosure] In the third aspect of the disclosure shown in Figure 3, a portion of the fuel tank 5 is located to the right in the side region of the power storage 4, as shown in the front view (F). The power storage 4 is heavy and has little freedom in shape, while the fuel tank 5 has a high degree of freedom in shape, allowing for effective use of the side space of the power storage 4. This arrangement improves space efficiency while ensuring weight balance. In some cases, a portion of the fuel tank 5 may be located to the left. [Fourth aspect of the disclosure] In the fourth aspect of the disclosure shown in Figure 3, the fuel tank 5 includes a fuel lid 6, and as shown in the front view (F), the fuel lid 6 is located to the right in the peripheral region of the power storage 4. The fuel lid 6 constitutes the fuel filler port and is a component that requires periodic access. This arrangement ensures ease of operation during refueling while avoiding interference with the power storage 4. The fuel lid 6 may also be located on the left. [Fifth aspect of the disclosure] In the fifth aspect of the disclosure shown in Figure 4, the power storage 4 is located on the vehicle body centerline (CL), and the fuel lid 6 is located to the right of the area surrounding the power storage 4. The power storage 4 is one of the heaviest parts in the vehicle, and its central positioning makes it easier to balance the weight between the left and right sides. In addition, the lateral positioning of the fuel lid 6 ensures ease of refueling. The fuel lid 6 may also be located on the left. [Sixth aspect of the disclosure] As shown in the front view (F) of Figure 4, a part of the power storage 4 is located between the control device 13 and the fuel tank 5. The control device 13 is a controller that controls the operation of the drive motor 3, and requires an electrical connection with the power storage 4. This arrangement minimizes the wiring route and achieves both controllability and space efficiency. The control device 13 is located on the left, and the fuel tank 5 is located on the right. In some cases, the control device 13 may be located on the right and the fuel tank 5 on the left.[Seventh aspect of the present disclosure] As shown in the right side view (R) of Figure 4, a portion of the fuel tank 5 overlaps with the shock absorber 12 when viewed from the left to right of the vehicle body. The shock absorber 12 is a shock absorber that absorbs shocks from the road surface, and requires operating space around it. Because the fuel tank 5 has a high degree of freedom in shape, it is positioned to overlap while avoiding this operating space, thereby efficiently utilizing the limited space of the vehicle body. The shock absorber 12 is positioned on the vehicle centerline CL. In addition, the shock absorber 12 may be positioned at an offset to the right or left of the vehicle centerline CL. [Eighth aspect of the present disclosure] As shown in the right side view (R) of Figure 4, the uppermost end (TEFT) of the fuel tank 5 is located in front of the vehicle than its lowermost end (BEFT). Compared with conventional fuel tank structures that are long in the front-to-rear direction, this forward-tilting arrangement allows for effective use of space at the rear of the vehicle body. This allows for efficient placement in accordance with the vehicle body shape while maintaining the effect of suppressing fluctuations in the center of gravity due to the vertical positional relationship with the power storage 4 (the uppermost end of the fuel tank 5 is higher than the lowest end of the power storage 4, and the lowest end of the fuel tank 5 is lower than the lowest end of the power storage 4). This forward-tilting arrangement improves the design freedom for arranging the fuel tank 5 in accordance with the vehicle structure and increases the freedom of vehicle layout in the longitudinal direction. As a result, it is possible to achieve a short wheelbase while simultaneously suppressing fluctuations in the center of gravity during lean driving and improving the placement efficiency of the fuel tank 5. [Ninth Embodiment of the Disclosure] Figure 5 is a plan view (P) showing the ninth embodiment of the Disclosure. In this embodiment, the fuel tank 5 is divided and arranged on both the left and right sides of the power storage 4 which is located on the vehicle body centerline (CL). Specifically, the fuel tank 5 consists of a left side tank and a right side tank, each located in the side region of the power storage 4. By dividing and arranging the fuel tank 5 in this way, the following effects can be obtained. Firstly, the heavy power storage unit 4 can be positioned on the vehicle's centerline (CL), while the space on either side can be effectively utilized. This makes it possible to secure the necessary capacity of the fuel tank 5 while suppressing the vehicle's dimensions in the longitudinal direction.Secondly, the left and right fuel tanks 5 maintain a basic positional relationship with the power storage 4 in the vertical direction (the uppermost point of the fuel tank 5 is higher than the lowest point of the power storage 4, and the lowermost point of the fuel tank 5 is lower than the lowest point of the power storage 4). This arrangement allows for maintaining the left-right weight balance during fuel consumption while suppressing fluctuations in the center of gravity (G). Furthermore, the left and right fuel tanks 5 are connected by a connecting section, and this connecting structure automatically equalizes the fuel level through the action of gravity. As a result, the fuel level is automatically equalized on both sides. This structure minimizes fluctuations in the left-right weight balance during refueling and fuel consumption.

[0010] Figure 6 shows a comparison of the specifications of the hybrid lean vehicle and the engine lean vehicle described in the background technology section. This comparison chart shows the main specifications of both vehicles, including engine displacement, minimum ground clearance, seat height, wheelbase, minimum turning radius, fuel tank capacity, vehicle weight, maximum system output, and maximum system torque.

[0011] CL: Vehicle Centerline: Vehicle Centerline BEPS: Bottom Edge of the Power Storage: Bottom Edge of the Power Storage BEFT: Bottom Edge of the Fuel Tank: Bottom Edge of the Fuel Tank TEFT: Top Edge of the Fuel Tank: Top Edge of the Fuel Tank BETM: Bottom Edge of the Traction Motor: Bottom Edge of the Traction Motor TETM: Top Edge of the Traction Motor: Top Edge of the Traction Motor 1: Lean Vehicle: Lean Vehicle 2: Engine: Internal Combustion Engine 3: Traction Motor: Traction Motor 4: Power Storage: Accumulatore di Energia: Power Storage 5: Fuel Tank: Serbatoio Carburante: Fuel Tank 6: Fuel Lid: Sportello Carburante: Fuel Lid 7: Frame: Telaio: Frame 8: Seat Rail: Guida del Sedile: Seat Rail 9: Drive Wheel: Ruota Motrice: Drive Wheel 10: Front Wheel: Ruota Anteriore: Front Wheel 11: Rear Swing Arm Assembly: Gruppo Forcellone Oscillante: Rear Swing Arm Assembly12: Shock Absorber: Ammortizzatore: Shock absorber 13: Control Unit: Control Unit: Control Unit G: Center of Gravity: Center of Gravity R: Right side view: Vista Laterale Destra: Right side view L: Left side view: Vista Laterale Sinistra: Left side view F: Front view: Vista Frontale: Front view P: Plan View: Vista in Pianta: Plan view VCGP: Variation in Center of Gravity Position: Variation in Center of Gravity Position

Claims

1. A hybrid lean vehicle comprising an engine, a drive motor, drive wheels driven by them, a power storage unit that supplies power to the drive motor, and a fuel tank that supplies fuel to the engine, wherein the fuel tank is positioned such that, when the lean vehicle is in an upright position, its uppermost end is higher than the lowest end of the power storage unit located above the engine, and its lowermost end is lower than the lowest end of the power storage unit located above the engine.

2. A hybrid lean vehicle according to claim 1, wherein the fuel tank is formed asymmetrically when viewed from the front of the vehicle.

3. A hybrid lean vehicle according to claim 1 or 2, wherein the fuel tank is provided such that at least a portion thereof is located in at least one direction, to the right or to the left, in the lateral region of the power storage provided above the engine.

4. A hybrid lean vehicle according to claim 1, 2, or 3, wherein the fuel tank includes a fuel lid, and the fuel lid is positioned to the right or left in the area surrounding the power storage located above the engine, in a front view of the vehicle.

5. A hybrid lean vehicle according to claim 4, wherein the fuel lid is positioned to the right or left in the area surrounding the power storage located on the centerline of the vehicle body when viewed from the front of the vehicle.

6. A hybrid lean vehicle according to claim 1, 2, 3, 4, or 5, wherein the power storage is provided such that, in a front view of the vehicle, at least a portion thereof is located between the control device for controlling the drive motor and the fuel tank.

7. A hybrid lean vehicle according to claim 1, 2, 3, 4, 5, or 6, wherein at least a portion of the fuel tank overlaps with at least a portion of the shock absorber when viewed from the left to right of the vehicle body.

8. A hybrid lean vehicle according to claim 1, 2, 3, 4, 5, 6, or 7, characterized in that the fuel tank is provided such that its uppermost end is located forward of the vehicle above its lowermost end.

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