FIELD OF INVENTION:
[001] The present subject matter described herein, relates to a fuel tank structure of vehicles, and, in particular, to aerodynamic structure of fuel tank for reducing drag force at underbody of vehicle. More particularly, the present subject matter 5 relates to an aerodynamic structure of fuel tank which deflects air away from rear suspension region.
BACKGROUND AND PRIOR ART:
[002] In vehicles, fuel economy in relation with speed of vehicle is a prime concern. Improvement in the fuel economy can be achieved by modifying the 10 engine design and improvements in fuel composition. However, the size and shape of the vehicles plays a substantial role in fuel economy. Ultimately, drag is the greatest enemy to fuel economy and speed of vehicle. Therefore, fuel consumption is influenced by the amount of drag forces incurred by the vehicle while travelling. As the drag forces increase, fuel consumption also increases. 15
[003] There are several areas on the vehicle which contributes in the drag forces. Generally, drag forces is a function of two components, i.e., friction drag and pressure drag. Friction drag is a force that acts tangential to a surface of the body. Friction drag is increased by irregularities or roughness on the surface and decreased by making the surface more slippery. On the other hand, pressure drag 20 is a force that acts perpendicular to a surface. The pressure drag is a function of the surface area in the direction of travel as well as the velocity or speed at which the vehicle body is travelling.
[004] The vehicle, specifically, passenger vehicles, are designed to overcome the pressure drag. The structure and shape of fuel tank also plays an important role in 25 aerodynamic drag of vehicle.
[005] Referring to figure 1, the fuel tank mounting 100 beneath the vehicle floor is disclosed. The fuel tank 102 is mounted under the vehicle floor 101 facing the ground. A rear axle 103 is mounted on vehicle rear floor 104. Further, there is a
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area 105 in between the fuel tank 102 and the rear axle 103. Figure 2 and 3 illustrates isometric and side views of the fuel tank 102, 200. At beneath of the vehicle, air flow in the vicinity of the rear axle influences aerodynamic drag of the vehicle heavily. The air moves along surface of the fuel tank 102 and the fuel tank 102 directs the air towards the rear axle 103. The air moves and hits the rear axle 5 103 induces drag on vehicle as shown in the figure 9. In the figure 9, the air 106 moves and hit the rear axle 103 which induces drag on the vehicle and increases the consumption of the fuel. After the air 106 hits the rear axle 103 gets entrapped in the region/area 105 between the rear axle 103 and the under body 101 or the fuel tank 102 which further increases the aerodynamic drag. 10
[006] In the existing design and structure of the fuel tank 102, the fuel tank 102 only serves the basic purpose of storing the fuel of the vehicle. The fuel tank 102 increases the aerodynamic drag on the vehicle if not designed properly by directing the flow directly towards the rear suspension/axle 103.
[007] At high speeds, these conventional structure of the fuel tank develops a 15 substantial amount of turbulent airflow in and around the undercarriage or beneath of the vehicle. This turbulence results in significant aerodynamic drag which increases the fuel consumption and high emissions.
[008] It would, therefore, be desirable to provide a drag reduction structure for fuel tank for a vehicle that overcomes the aforesaid and other disadvantages. 20 Consequently, there is a need for making the under body fuel tank more aerodynamic to reduce the impact of the fuel tank on the overall drag of a vehicle. The fuel tank should be inexpensive, reliable, simple in manufacturing, and can be implemented on existing fuel tanks. Therefore, the present invention provides a solution by satisfying all the requirements which suited best for the automobile 25 industry.
OBJECTS OF THE INVENTION:
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[009] The principal objective of the present invention is to provide an aerodynamic structure of fuel tank for reducing the aerodynamic drag of the vehicle.
[0010] Another object of the present subject matter is to provide an aerodynamic structure of fuel tank which deflects air away from the rear axle. 5
[0011] Yet another object of the present subject matter is to provide an aerodynamic structure which can be mounted on fuel tank to improve the aerodynamic drag at underbody of the vehicle.
[0012] Yet another object of the present subject matter is to provide a simple, effective, and cost efficient aerodynamic structure of water tank to reduce the 10 aerodynamic drag at underbody of the vehicle to increase the fuel efficiency and balance of the vehicle on the road.
SUMMARY OF THE INVENTION:
[0013] The subject matter disclosed herein relates to an aerodynamic fuel tank structure of the vehicle for reducing aerodynamic drag coefficient of the vehicle. 15 The fuel tank has the general purpose of storing the fuel of the vehicle. The present fuel tank structure improves the underbody air flow behavior in the vicinity of the rear axle. The fuel tank is designed to provide an inclined bottom with an extended surface to deflect the air away from the of the rear axle and to minimize entrapment of air in the region. The fuel tank structure is also provided 20 with an integrated edge like structure that deflects air away from the rear suspension region by disturbing the flow at the separation points of the extended surface. The combined effect of the inclined bottom, extended surface and integrated edge reduces the direct hitting of air with the rear axle thereby reducing the aerodynamic drag coefficient of the vehicle. 25
[0014] In order to further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit scope of the present subject matter.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0015] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the 5 accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods in accordance with embodiments of the present subject matter are now described, by way of example, 10 and with reference to the accompanying figures, in which:
[0016] Fig. 1 illustrates fuel tank mounting at underbody of the vehicle as general art;
[0017] Fig. 2 illustrates isometric view of the fuel tank, as known in the art;
[0018] Fig. 3 illustrate side view of the fuel tank, as known in the art; 15
[0019] Fig. 4 illustrates aerodynamic structure of fuel tank mounted at underbody or beneath of the vehicle, in accordance with an embodiment of the present subject matter;
[0020] Fig. 5 illustrates isometric view of the aerodynamic structure of the fuel tank, in accordance with an embodiment of the present subject matter; 20
[0021] Fig. 6 illustrates side view of the aerodynamic structure of the fuel tank, in accordance with an embodiment of the present subject matter;
[0022] Fig. 7 illustrates cross section of the aerodynamic structure of the fuel tank, in accordance with an embodiment of the present subject matter;
[0023] Fig. 8 illustrates exploded view of the extended edge of the aerodynamic 25 structure of the fuel tank, in accordance with an embodiment of the present subject matter;
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[0024] Fig. 9 illustrates flow of air underbody of the vehicle with existing fuel tank as known in the art; and
[0025] Fig. 10 illustrates flow of air underbody of the vehicle with the aerodynamic structure of the fuel tank, in accordance with an embodiment of the present subject matter. 5
[0026] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein. 10
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[0027] The subject matter disclosed herein relates to an aerodynamic fuel tank structure for reducing aerodynamic drag coefficient beneath vehicle body. The fuel tank has the general purpose of storing the fuel of the vehicle. The present subject matter improves the underbody air flow behavior in the vicinity of the rear 15 axle in the vehicle. The aerodynamic fuel tank structure is a tank for fuel which is mounted to underbody of the vehicle body. The fuel tank has a leading face and a trailing face in the direction of travel of the vehicle. The fuel tank has upper surface and bottom surface. The bottom surface is inclined at an angle from the leading face to the trailing face to direct air flow away from rear axle. Further, the 20 bottom surface has an extended surface which is provided at edge of the trailing face to further deflect the air away from the rear axle and avoid hitting of air to the rear axle. In other words, the fuel tank is designed to provide an inclined bottom with an extended surface to deflect the air away from the rear axle and to minimize entrapment of air in the region between the fuel tank and the rear axle. 25 The fuel tank design is also provided with an integrated edge like structure that deflects air away from the rear suspension region by disturbing the flow at the separation points of the extended surface. The combined effect of the inclined bottom, extended surface, and integrated edge reduces the direct hitting of air with the rear axle thereby reducing the aerodynamic drag coefficient of the vehicle. 30
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[0028] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those 5 skilled in the art that by devising various assembly that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the 10 concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the 15 following description when considered in connection with the accompanying figures.
[0029] These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject 20 matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.
[0030] The present fuel tank is designed to reduce the aerodynamic drag coefficient of a vehicle by influencing the air flow near the vicinity of the rear 25 axle. The bottom surface of the fuel tank and the extended structure is designed in such a way that the air is guided away from hitting the rear axle directly.
[0031] Fig. 4 illustrates aerodynamic structure of fuel tank mounted at underbody or beneath of the vehicle, in accordance with an embodiment of the present subject matter. The assembly 400 includes vehicle floor 401, fuel tank 402, rear 30
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axle 403, and vehicle rear 404. The fuel tank 402 has the general purpose of storing the fuel of the vehicle. The fuel tank 402 is mounted on underbody or vehicle floor 401 of the vehicle. The rear axle 403 is mounted after the fuel tank 402 on the vehicle floor 401. Further, there is a gap in between the fuel tank 402 and the rear axle 403. The fuel tank 402 has aerodynamic structure for reducing 5 the aerodynamic drag coefficient.
[0032] Fig. 5 illustrates isometric view of the aerodynamic structure of the fuel tank, in accordance with an embodiment of the present subject matter. The aerodynamic fuel tank structure 500 is fuel tank 501 for storing the fuel of the vehicle. The fuel tank 501 has leading face 501a and a trailing face 501b in 10 direction of the vehicle. The fuel tank 501 has upper surface and a bottom surface 501c. The leading face 501a, the trailing face 501b, the upper surface, and the bottom surface 501c combined with each other and define a rectangular storage box or storage fuel tank. The fuel tank 501 has several mounting points for mounting the fuel tank 501 on the vehicle floor 401. The bottom surface 501c is 15 inclined at an angle from the leading face 501a to the trailing face 501b to direct air away from the rear axle 403 mounted behind the fuel tank 402, 501. The angle 505 is in range 5o to 25o as shown in the figure 6. Further, the inclined angle 505 can be optimized based on the dimensions of the vehicle and aerodynamic drag coefficient at underbody of the vehicle. 20
[0033] Referring to figure 6, an extended surface 504 is provided at edge of the bottom surface 501c at trailing face 501b. The extended surface 504 is extended away from the trailing face 501b towards the rear axle 403. The inclined bottom surface directs the flow of the air in down ward direction.
[0034] Referring to figure 7 and 8, the extended surface 504 has an edge 504a like 25 structure to further facilitate to deflect air away from rear axle 403 of the vehicle. The extended surface 504 and the edge 504a cumulatively help in minimizing the aerodynamic drag on the vehicle by deflecting the air away from the rear axle 403. The edge 504a is provided at bottom of the extended surface 504 to deflect air more effectively away from the rear axle. The edge 504a has height 504c which 30
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can be optimized based on the vehicle dimensions and the ground clearance of the vehicle. Length 504b of the extended surface 504 can also be optimized based on the vehicle dimensions and ground clearance. Further, the length of the extended surface 504 can be increased and decrease to improve the aerodynamic drag coefficient. For example, more the length, air deflection from the rear axle is 5 more, this concept is clearly visible from the figure 10.
[0035] The important parameters of the aerodynamic fuel tank structure are the angle of fuel tank bottom surface 505(α), length of extended surface (l) 504b, and the height (h) 504c of the edge 504a placed at the end of the extended surface 504 as shown in fig. 7 and 8. Maximum possible reduction in aerodynamic drag is 10 obtained by optimization of these parameters. The taper angle 505 should be in the range of 5 to 25 degree, preferably in range of 5 to 10 degree and it can vary with vehicle overall design. The length (l) and height (h) of the extended surface 504 and the edge 504a respectively are dependent on the styling of the vehicle and its ground clearance. 15
[0036] In another embodiment of the present subject matter, the inclined/sloping bottom surface and the extended surface with edge can also be employed as a separate part made of the same material as that of the tank. This aerodynamic jacket structure can be mounted on the bottom surface of the fuel tank of the vehicle. The aerodynamic jacket structure can be mounted on the existing fuel 20 tanks or on the fuel tank of the used vehicles. The aerodynamic jacket structure not only improves the air flow behavior in the underbody but also act as a tank guard to protect fuel tank. The aerodynamic jacket structure includes an inclined base surface mountable on the bottom surface of the fuel tank. The inclined base surface has an extended surface with an edge. The edge has a height which can be 25 adjust based on the vehicle dimensions and ground clearance. Upon mounting on the bottom surface of the fuel tank, the aerodynamic jacket structure deflects air flow away from rear axle and avoids hitting of the air flow on the rear axle and entrapping of air flow in between the fuel tank and the rear axle.
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[0037] Figure 9 illustrates the air flow path in the existing fuel tanks. In the existing designs, the fuel tank 200 directs the air 106 towards the rear axle 103. As shown in the figure, air 106 hits the rear axle as it comes from the front. The more the air that interacts with the rear axle 103, more is the amount of air that gets entrapped in between the area 105 thereby increasing the aerodynamic drag on the 5 vehicle.
[0038] Figure 10 illustrates the air flow path of in the present aerodynamic fuel tank structure. The fuel tank 500 has an inclined bottom surface with an extended surface and edge that guides the air 506 away from the rear axle 403 and thus reduces the entrapment of air in the underbody region thus reducing the 10 aerodynamic drag on the vehicle.
[0039] The present aerodynamic fuel tank structure or aerodynamic jacket structure is easy and fast to manufacture. Further, the present aerodynamic jacket structure can be mounted or assembled on the existing fuel tank to provide aerodynamic features. The aerodynamic fuel tank has inclined bottom surface due 15 to which air leaves the bottom surface at angle. Further, when the released air tries to move upward, the extended surface integrated with an edge further deflects the air flow away from the rear axle and thus further improving the drag of the vehicle.
[0040] The term “vehicle” as used throughout this detailed description and in the 20 claims refers to any moving vehicle that is capable of carrying one or more human occupants and is powered by any form of energy. The term “vehicle” is a motor vehicle which includes, but is not limited to: cars, trucks, vans, minivans, hatchback, sedan, MUVs, and SUVs.
[0041] It will be further appreciated that functions or structures of a plurality of 25 components or steps may be combined into a single component or step, or the functions or structures of one-step or component may be split among plural steps or components. The present invention contemplates all of these combinations. Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the invention, and other 30
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dimensions or geometries are possible. In addition, while a feature of the present invention may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof 5 also constitute methods in accordance with the present invention. The present invention also encompasses intermediate and end products resulting from the practice of the methods herein. The use of “comprising” or “including” also contemplates embodiments that “consist essentially of” or “consist of” the recited feature. 10
[0042] Although embodiments for the present subject matter have been described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/component 15 of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.

We claim:
1. An aerodynamic fuel tank structure (500) for reducing aerodynamic drag beneath vehicle body, the aerodynamic fuel tank structure (500) comprising:
a fuel tank (501) for a fuel mountable to underbody (401) of the vehicle body, the fuel tank (501) comprises: 5
a leading face (501a) and a trailing face (501b) in the direction of travel of the vehicle;
characterized in that
wherein bottom surface (501c) inclined at an angle (505) from the leading face (501a) to the trailing face (501b) to direct air away 10 from rear axle (403);
an extended surface (504) provided at edge of the bottom surface (501c) at the trailing face (501b) to deflect the air away from the rear axle (403) and avoid hitting of air from the rear axle (403). 15
2. The aerodynamic fuel tank structure (500) as claimed in claim 1, wherein the angle (504) is in range of 5o to 25o.
3. The aerodynamic fuel tank structure (500) as claimed in claim 1, wherein 20 the angle (504) depends on dimensions of the vehicle and aerodynamic drag coefficient at underbody (401) of the vehicle.
4. The aerodynamic fuel tank structure (500) as claimed in claim 1, wherein the extended surface (504) extended away from the trailing face (501b) 25 towards rear axle (403).
5. The aerodynamic fuel tank structure (500) as claimed in claim 1, wherein the extended surface (504) comprises an edge (504a) with height (504c).
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6. The aerodynamic fuel tank structure (500) as claimed in claim 1, wherein length (504b) and height (504c) of the extended surface (504) depends on styling and ground clearance of the vehicle.
7. An aerodynamic jacket structure () which mounted on bottom surface (501c) 5 of fuel tank (500) of vehicle to reduce aerodynamic drag, the aerodynamic jacket structure comprises:
an inclined base surface with an angle (504d, α) mountable of the bottom surface (501c) of the fuel tank (500); 10
wherein the inclined base surface has an extended surface with an edge, the edge has height which deflect the air;
upon mounting on the bottom surface of the fuel tank (500), the aerodynamic jacket structure deflects air flow away from rear axle and avoid hitting of the air flow on the rear axle and entrapping of air flow in 15 between the fuel tank and the rear axle.
8. The aerodynamic jacket structure () as claimed in claim 7, wherein the angle is in range of 5o to 25o.