SE541338C2

SE541338C2 - Vehicle fuel tank comprising a baffle

Info

Publication number: SE541338C2
Application number: SE1751231A
Authority: SE
Inventors: Anders Wedholm; Carl-Johan Waldner; Erik Andersson; Johan Göransson; Jonas Wikström; Rasmus Johansson; Sillén Wilhelm Af
Original assignee: Scania Cv Ab
Priority date: 2017-10-05
Filing date: 2017-10-05
Publication date: 2019-07-16
Also published as: DE102018007389A1; SE1751231A1

Abstract

A vehicle fuel tank, vehicle and method is provided. The vehicle fuel tank (2) comprises at least one tank baffle (5) with a wall portion extending in a third plane and at least one flange (9) with at least one peripheral flange surface (9a) arranged to at least partly face an inner surface (4a) of the shell (4) of the tank. The inner surface of the shell comprises a first set (6) of at least two distinct protrusions (16, 26), each with at least one first shell surface portion (16a, 26a) arranged to extend substantially in the longitudinal direction (L) and at least one second shell surface portion (16b, 26b) arranged with a first angle ( α) relatively the longitudinal direction. The at least one peripheral flange surface (9a) comprises at least two distinct recesses (15, 25), each recess comprises at least one first flange surface portion (15a, 25a) arranged to extend substantially in the longitudinal direction (L) and at least one second flange surface portion (15b, 25b) arranged with a second angle (α) relatively the longitudinal direction. Further the tank comprises an adhesive bond (10) between the second shell surface portion (16b, 26b) and the corresponding second flange surface portion (15b, 25b).

Description

Vehicle fuel tank comprising a baffle Field of the invention The present invention generally relates to a fuel tank for a vehicle. The invention also relates to a vehicle comprising a fuel tank and a method for manufacturing a fuel tank.

Background of the invention A baffle forms a flow obstructing panel inside a tank, such as a fuel tank. The baffle reduces, or prevents, large movements of liquid inside the tank when the tank is subjected to acceleration. The baffle is configured to admit limited passage of liquid past the baffle to allow emptying of all the liquid from the tank.

Tanks for commercial vehicles are typically made of aluminium or steel and the baffles are provided with flanges that are welded to the inside wall of the tank. Welding of baffles to the shell create residual stresses in flanges of the baffle and in the shell of the tank.

The forces on a baffle caused by sloshing fluid and movement of the tank during operation of the vehicle may cause mechanical fatigue in the tank. The fatigue may lead to cracks forming at the welds between the baffles and the shell. The cracks may in turn cause the fuel tank to leak.

JP2013035429 discloses a tubular fuel tank that has a rectangular cross section. The walls of the fuel tank include two protrusions protruding inwardly. A flange of a baffle is press-fitted between the protrusions to position the baffle inside the fuel tank. The baffle suppress movement of fuel in the fuel tank. Welding of the baffle is not required.

EP 24047766 A2 discloses a fuel tank for a vehicle with inner walls or baffles. The baffles have flanges that orient the baffle in the tank hull. The baffles are glued to the hull, either glue is added to the inner wall of the hull and the baffle is pushed in position where the it comes in contact with the glue, or the flange has a bulge, creating a cavity between the flange and the inner wall of the hull, that is filled with glue through a hole in the flange, once the baffle is positioned in the hull.

Welding the baffle to the inside of the fuel tank or adding glue to the inside of the fuel tank may also introduce complications with reach and sight during manufacturing, thereby increasing the complexity of manufacturing of a tank for a vehicle.

Summary of the invention It would be advantageous to achieve a tank and a method for manufacturing a tank overcoming, or at least alleviating, the above mentioned drawbacks. In particular, it would be desirable to enable a fuel tank that is more durable, in particular at the joints between the baffles and the shell, as well as a method for manufacturing a fuel tank that is less complex and/or more economically efficient. To better address one or more of these concerns, a tank and a method for manufacturing a tank having the features defined in the independent claims are provided. Preferable embodiments are defined in the dependent claims.

The applicant has discovered that geometrical form locks of baffles such as press fitting may initiate cracks in the tank due to frictional wear between the joined components.

Hence, according to an aspect, a vehicle fuel tank is provided. The tank comprises a tank body with a first end plate extending in a first plane, a second end plate extending in a second plane and a shell that extends in a longitudinal direction between the first plane and the second plane, such that inner surfaces of the first end plate, the second end plate and the shell forms an interior space for holding fuel. The tank further comprises at least one tank baffle with a wall portion extending in a third plane and at least one flange with at least one peripheral flange surface arranged to at least partly face the inner surface of the shell. The inner surface of the shell comprises a first set of at least two distinct protrusions, each with at least one first shell surface portion arranged to extend substantially in the longitudinal direction and at least one second shell surface portion arranged with a first angle relatively the longitudinal direction. The at least one peripheral flange surface comprises at least two distinct recesses, each recess comprises at least one first flange surface portion arranged to extend substantially in the longitudinal direction and at least one second flange surface portion arranged with a second angle relatively the longitudinal direction. Further the tank comprises an adhesive bond between the second shell surface portion and the corresponding second flange surface portion.

Since the shell comprises a first set of at least two distinct protrusions and the at least one peripheral flange surface comprises at least two distinct recesses, correct positioning of the baffle during manufacturing is facilitated.

By the connection between the protrusions and recesses in an angle to the longitudinal direction in which the flange and the inner surface of the wall is joined, good geometrical locking is achieved and the load on the adhesive bond is decreased. By combining form locking and adhesive locking, a bond is achieved that reduces the risk for cracks in the tank compared with welded bonds or geometrical, form locked, bonds, and less risk for the baffle coming loose than adhesive bonds.

In the present specification, the term protrusion may include any shape in which the inner surface of the shell may be reducing the radius of inner wall in certain positions. According to embodiments of the invention, the inward protrusions are embossings in the shell.

The invention may be particularly useful for commercial vehicle, especially heavy trucks, buses and lorries and for construction equipment, such as excavators. On trucks and lorries, the fuel tanks are typically shaped as right prisms with rectangular, D-shaped or circular side surfaces. The tank is usually attached to the frame of the vehicle with brackets. The brackets are connected to the shell of tank, often by bands clasping the tank shell. A typical tank of a heavy vehicle holds 200 - 1000 litres of fuel, typically a fluid hydrocarbon such as diesel, petrol or FAME.

In the present specification, the term fuel also relates to any fuel additive that is carried in a separate tank on the vehicle. Such additives are any ammonium salt solutions in water, such as urea solution AUS 32 in ISO 22241, commercially available as AdBlue<®>or DEF.

The fuel tanks of heavy vehicles are exposed to large forces from the relative motion between the tank and the frame of the vehicle, typically in the connection between the tank and the fastening means, e.g. the bands and the brackets. As mentioned above, the tank is also subjected to large forces from the sloshing of fuel in the tank during acceleration and deceleration of the vehicle. The baffles in a fuel tank reduces the sloshing and as they are provided with openings for the fuel to pass through, the fuel is kept at the same level in all sections of the tank created by the baffles. Such problems are generally not present for passenger cars and other vehicles with small tanks, as these tanks usually have other shapes and are exposed to much smaller forces.

Adhesive, i.e. glued, joints are strong in shearing, but weaker in cleavage and peeling stresses. The forces of the baffles are mainly longitudinal, and a typical adhesive joint between a baffle and a shell is between a longitudinal flange of the baffle and the inner wall of the shell. Flowever, the inventors of the present invention has realised that when the baffle is exposed to longitudinal forces, the forces on the joint between the baffle and the shell is to a high extent directed in the directions transverse to the longitudinal direction, i.e. in the plane of the baffle, as the baffle bulges or flexes under the forces from the sloshing fuel, thereby subjecting a baffle joint for cleavage and peeling stresses. A glued baffle may thereby come lose from the wall, and thereby not reduce the movements of liquid, resulting in breakage of the tank. The inventors has realised that by combining a geometrical form locking with an adhesive bond locking between two surfaces that are arranged at an angle relative to the longitudinal direction, the risk of friction wear between the baffle flange and the shell in the form locking is reduced, and as the adhesive bond is arranged at an angle to the longitudinal direction, the bond is mainly subjected to shearing stresses, thereby achieving a very strong adhesive bond.

The adhesive can be any suitable adhesive known in the art.

The at least one peripheral flange surface may be arranged to at least partly abut the inner surface of the shell.

Cracks in adhesive bonds often start in a single weak spot, e.g. where there are geometrical or material imperfections or impurities in the bond, and then the crack follows the joint until the end of the joint. Hence, by providing the peripheral flange surface with at least two distinct recesses and the inner surface of the shell with at least two distinct protrusions, the baffle is joined to the shell by distinct joints, thereby reducing the risk for cracks spreading in the tank.

According to an embodiment, the second shell surface portion and the second flange surface portion are complementary shaped relatively each other. Thereby a strong adhesive bond is achieved.

According to an embodiment, the first and second angles are 30° - 60°, more preferably 40° - 50°. With these angles, the cleavage and pealing stresses in the adhesive bond is reduced.

According to an embodiment, the first, second and third planes are substantially parallel relatively each other. By arranging the planes this way, the tank has the shape of a right prism and can be space effectively installed at the frame of a vehicle. Also, this facilitates that several tank sizes can be built by only changing the length of the shell of the tank, meaning that a cost effective modular tank system can be achieved.

According to an embodiment, the recesses in the flange are arranged at an edge of the flange in the longitudinal direction, so that the flange surface encloses less or equal to half of the circumference of the recesses. With the recesses open in one side, mounting of the baffle at manufacturing is simplified, as the baffle may be slid into position against the protrusions in the shell before the end wall is fitted to the shell. In a tank with two baffles, one baffle can be inserted from each open side of the shell before fitting the end walls of the tank. Further, by arranging the recesses with an open side, adhesive can be added to the second flange surface portion before the baffle is sled into place in the shell, without the adhesive getting in contact with the shell until the second flange surface portion abuts the second shell surface portion. Thereby, simplified joining of the baffles to the tank shell is facilitated compared with methods where the adhesive is added through holes in the shell or to the inside wall of the shell.

According to a preferred embodiment, the tank comprises a second tank baffle and the shell comprises a second set of at least two distinct protrusions. In trucks, the size of the tanks often makes two baffles a suitable compromise between strength and sloshing control on one hand, and cost and weight on the other hand. Further, as mentioned above, two baffles are suitable as they can be mounted from different sides of the shell, before attaching the end plates to the shell.

According to an embodiment, the end plates and the baffle wall portion are circular or oval. Circular baffles provides a tank with very good strength, as the forces from the moving (sloshing) fuel is relatively evenly distributed to the whole flange, and there is no corners where forces in different directions meet. According to a further embodiment, the baffle wall portion is substantially polygonal and the flange comprises a recess in each corner of the polygon. With the baffle wall portion and the first and second end plates substantially polygon, more effective usage of the space on the vehicle's frame is facilitated than with circular cross sections. Thereby the vehicle may carry more fuel and/or space on the frame that would otherwise be used for the fuel tank can be used for other components or cargo, thereby increasing the load capacity of the vehicle. The polygon can typically be rectangular or "D"-shaped. By arranging joints in the corners of the polygon, the negative effects of the corners can be significally reduced, thereby increasing the strength of the tank. The corners does not have to be sharp, but should preferably have a radius. The radius of the corner could preferably be 10 - 40% of the length of the side of the polygon, e.g. the width of the tank. According to a further embodiment, the baffle wall portion is a superellipse, and the flange comprises a recess where a flange radius, i.e. the radius of the superellipse, is at its minima. By arranging the recesses at radii minimas, the strength of the tank is improved.

According to an embodiment, the flange comprises a plurality of distinct indentions in the third plane. As an example, for a tank with a substantially square cross section, the flange may comprise an indention in every corner and one indention on every side, 8 indentions in total.

According to an embodiment, at least two different two adhesives is used in different adhesive bonds; a first adhesive with a first elastic modulus, and a second adhesive with a second elastic modulus. The second elastic modulus may be larger than the first elastic modulus, and the first adhesive may used in the adhesive bonds in stiff parts of the shell and/or the baffle such as in corners or radii minima, and the second adhesive may be used in less stiff regions of the shell and/or the baffle, such as near the centre of the sides or radii maxima. Stiffer, i.e. less elastic, adhesive gives a more rigid bond but is less flexible and have higher risk of cracking in presence of cleavage and pealing stresses due to large movements between the part of the joint. By combining less elastic adhesive in regions where the structure is stiffer, such as in the corners of polygonal baffles, with a more elastic adhesive in regions where the structure is more flexible, such as at the middle of the sides of a polygonal baffle, a tank may be achieved that is both rigid and withstand loads due to resilience of the components of the tank.

According to embodiments the end plates and the shell comprise aluminium. Tanks in aluminium, in the context of this specification, aluminium may also be any alloy where aluminium is the main component, provides a good compromise between weight, strength and cost. The shell can be made of any suitable material, such as high-tensile steel or reinforced composite, such as carbon fibre composite.

According to embodiments, the baffle and the shell are made of different materials with different mechanical properties. As an example the shell may be made from aluminium, while the baffle is made from composite. This may save weight, as the baffle does not have to carry as much static load as the shell and also does not have to be resistant to impact as it is protected inside the hull of the tank. In a steel tank, the baffle may be made of aluminium. By making the baffle in composite, the geometry of the baffle may be optimised, e.g. by varying thickness in different regions of the baffle. The baffle may be made in a material that is has different elasticity and/or stiffness than the shell. According to other embodiments, the baffle(s) are made from the same material as the shell but of different thickness than the shell. When welding the baffles to the shell, the baffle and the shell needs to be of approximately the same thickness. According to embodiments, the baffle(s) are thinner than the shell. This may save weight, as the baffle may be thinner as it does not have to carry as much static load as the shell and also does not have to be resistant to impact as it is protected inside the hull of the tank.

According to a second aspect, a vehicle comprising at least one tank according to any one of the aspects and/or embodiments discussed herein is provided. The vehicle is preferably a heavy vehicle such as a truck or a bus, as the tank discussed herein is particularly well suited to be mounted to a frame of the vehicle. The vehicle may also be any other type of vehicle with this type of tanks, such as construction vehicles e.g. excavators or mobile cranes, or boats or ships.

According to a third aspect, a method for manufacturing a tank according to any of the embodiments described herein is provided. The method comprises providing a shell, comprising a first set of at least two distinct protrusions, each with at least one first shell surface portion arranged to extend substantially in a longitudinal direction of the shell and at least one second shell surface portion arranged with a first angle relatively the longitudinal direction and also providing a baffle, with a wall portion extending in a third plane and at least one flange with at least one peripheral flange surface arranged to at least partly face the inner surface of the shell, the baffle comprising at least two distinct recesses, each recess comprises at least one first flange surface portion arranged to extend substantially in the longitudinal direction and at least one second flange surface portion arranged with a second angle relatively the longitudinal direction, the recesses being arranged at an edge of the flange in the longitudinal direction, so that the flange surface encloses less or equal to half of the circumference of the recesses. The method then comprises the step of adding adhesive to the second flange surface portion and further inserting the baffle into the shell until the second flange surface portions abuts the second shell surface portions, creating adhesive joints between said surface portions and finally the step of setting the adhesive joint.

It is noted that embodiments of the invention relates to all possible combinations of features recited in the claims. Further, it will be appreciated that the various embodiments described for the tank are all combinable with the method as defined in accordance with the third aspect of the present invention.

Brief description of the drawings Aspects of the invention will now be described in more detail in the following illustrative and non-limiting detailed description of embodiments, with reference to the appended drawings.

Fig. 1 shows a vehicle according to embodiments.

Fig. 2 shows a fuel tank body according to embodiments.

Fig. 3 shows a tank shell and a baffle according to embodiments in exploded view.

Fig. 4 shows a baffle according to embodiments.

Fig. 5 shows a tank shell and a baffle according to embodiments.

Fig. 6 shows a joint between a tank shell and a baffle flange according to embodiments.

Fig. 7 illustrates a method for manufacturing a fuel tank.

All the figures are schematic, not necessarily to scale, and generally only show parts which are necessary in order to elucidate the embodiments, wherein other parts may be omitted. Like reference numerals refer to like elements throughout the description.

Detailed description of embodiments Fig. l shows a vehicle 1 according to embodiments. The vehicle comprises a fuel tank 2 according to any one of embodiments discussed herein. The tank is attached to a frame 11 of the vehicle with installation bands that may extend at least partially around the fuel tank. The installation bands are attached to brackets (not shown), which brackets are attached to the frame.

Fig. 2 shows a fuel tank body 12 of the fuel tank 2 according to embodiments. The tank body comprises a first end plate 3a facing toward the front of the vehicle and a second end plate 3b facing aft of the vehicle. The end plates, or end walls, are joined by a shell 4. The volume of the tank body is typically 200 - 1000 litres. The end plates are typically welded to the shell. The end plates may be cambered or crowed in the longitudinal direction of the tank, the camber directed outward, forward and aft respectively.

The tank shell comprises sets of distinct, separate embossings 6, 7 creating inward protrusions in the shell as will be further discussed with reference to Figs. 3 - 6.

Fig. 3 shows a baffle 5 and a section of a shell 4 according to embodiments. Fig. 4 shows the baffle in more detail. The shell is provided with a plurality of inward directed embossings 16, 26. The embossings creates inward protrusions in the inner wall of the shell. The placement of the embossings and the number of embossings depends on the size and form of the tank. A typical installation comprises an embossing 25 in each corner of the shell and an embossing on every side. The baffle 5 comprises a wall portion 8 extending and a flange portion 9. The wall portion is typically cambered. The wall portion comprises a number of openings through which the fuel can flow. The sizes and position of the openings depend on the installation.

The baffle 5 comprises a flange 9. The baffle may be pressed from one sheet of metal. The flange comprises a number of embossings forming distinct recesses 15, 25 in a peripheral flange surface 9a. The positions of the recesses 15, 25 corresponds to the positions of the protrusions 16, 26 in the shell 4, as can be most clearly seen in Fig. 5.

Each protrusion has a first shell surface portion 16a, 26a that is substantially parallel with the shell wall 4a and that may be the portion of the protrusion that is furthest from the shell in a direction perpendicular to the shell. Each protrusion also has at least one second shell surface portion 16b, 26b that is arranged with an angle ?1relatively the longitudinal direction of the tank, i.e. a direction parallel with a line arranged between the centres of the endplates of the tank. The second surface may be positioned between the first shell surface portion and the shell. The second surface may be flat or curved. In case the surface is curved, the angle ?1is measured to the tangent in the position where the differential of the curvature changes sign.

Each indention has a first flange surface portion 15a, 25a that is substantially parallel with the flange and that may be the portion of the protrusion that is furthest from the flange in a direction perpendicular to the flange. Each indention also has at least one second flange surface portion 16b, 26b that is arranged with an angle ?2relatively the direction of the flange, and in mounted position, the longitudinal direction of the tank. The second flange surface may be positioned between the first flange surface portion and the flange. The second surface may be flat or curved, in case the surface is curved, the angle ?1may be measured to the tangent in the position where the differential of the curvature changes sign.

The recesses may be arranged at an edge of the flange in the longitudinal direction, so that the flange surface encloses less or equal to half of the circumference of the recesses, as can be clearly seen in Fig. 4. That is, the recesses has an open side. The baffle can thereby be slid into its intended position in the shell, where the second flange surface abuts the second shell surface.

As can be best seen in Fig. 6, the second shell surface portions 16b, 26b and the second flange surface portions 16b, 26b, are joined by an adhesive layer 10. The adhesive layer can be any suitable adhesive. Examples of suitable adhesives may be epoxies, anaerobics or modified phenolics. Suitable adhesives for each application are known to the skilled person and are not discussed further in this specification.

The baffle and the shell may be joined in a plurality of joints between recesses and protrusions.

An adhesive joint may be significally weakened if any part of the joint is separated. If the joint e.g. is separates in a corner of the joint, there is then a risk that the whole joint will be separated, even by relatively small peeling forces. By joining the baffle to the shell by means of a number of distinct, discreet joints, the effects of a crack in a joint may be isolated to that single joint. The number of protrusions/recesses in each set varies in depending on the size and shape of the tank. Depending on the application, the number and sizes of joints, i.e. the number of protrusions and recesses, will vary. It is advantageous that the distance between two adjacent joints are large enough that a peeling or cleaving joint does not easily spreads to the next joint. A suitable distance between two joints may be at least the width of the recesses.

As the second shell surface portion is positioned inward from the inner surface of the shell, an adhesive can be applied to the flange surface portions 16b, 26b before the baffle is positioned in the shell. Thereby application of the adhesive may be simplified during manufacturing, as the adhesive does not have to be applied to the inside of the shell.

The protrusions and indentions may have complementary shapes, which may facilitate strong joints both by form locking and adhesive locking. The second surface portion's angles ?1and ?2may be substantially identical. The angles are chosen so that the pealing and cleavage stresses in the adhesive joint may be minimized. In the illustrated embodiments, the angles may be 45°±5°.

A method according to another aspect will be described with reference to Fig. 7. In a step 120 an adhesive is applied to the second flange surface portion 15b, 25b. In a subsequent step 130, the baffle 5 is inserted into the shell 4 until the second flange surface portions 15b, 25b of the baffle abuts the second shell surface portions 16b, 26b of the shell. If the tank is to comprise a second baffle 5, the operation is repeated, inserting the second baffle from the other direction into the shell 4. Then the adhesive is let to set 140. Then the end plates are welded to the shell, closing the tank volume. Different adhesives may be used in different joints, as discussed above.

The person skilled in the art realizes that the present invention by no means is limited to the embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. For example, the tank does not have to be a right prism, and the plates and the baffle does not have to have the same cross section area. Further, the baffle does not have to be arranged perpendicular to the shell, but may be arranged at an angle, as long as the flange is also arranged at the same angle so that the flange and the shell abuts. The adhesive joint may also join the first shell surface portion and the first baffle shell portion. Further, the form fitted and adhesive joints can be combined with other types of joints. E.g. the flange may be spot welded to the shell in positions between the adhesive joints.

Claims

1. A vehicle fuel tank (2) comprising a tank body (12) with a first end plate (3a) extending in a first plane, a second end plate (3b) extending in a second plane and a shell (4) that extends in a longitudinal direction (L) between the first plane and the second plane, such that inner surfaces of the first end plate (3a), the second end plate (3b) and the shell (4) forms an interior space for holding fuel, at least one tank baffle (5) with a wall portion (8) extending in a third plane and at least one flange (9) with at least one peripheral flange surface (9a) arranged to at least partly face the inner surface (4a) of the shell (4), characterized in that the inner surface (4a) of the shell comprises a first set (6) of at least two distinct protrusions (16, 26), each with at least one first shell surface portion (16a, 26a) arranged to extend substantially in the longitudinal direction (L) and at least one second shell surface portion (16b, 26b) arranged with a first angle (?1) relatively the longitudinal direction(L); the at least one peripheral flange surface (9a) comprises at least two distinct recesses (15, 25), each recess comprises at least one first flange surface portion (15a, 25a) arranged to extend substantially in the longitudinal direction (L) and at least one second flange surface portion (15b, 25b) arranged with a second angle ( ) relatively the longitudinal direction (L); and in that the tank (2) comprises an adhesive bond (10) between the second shell surface portion (16b, 26b) and the corresponding second flange surface portion (15b, 25b).

2. The tank (2) according to claim 1, wherein the second shell surface portion (16b, 26b) and the second flange surface portion (15b, 25b) are complementary shaped relatively each other.

3. The tank (2) according to claim 1 or 2, wherein the angles ?x, ?yare 30° - 60°, more preferably 40° - 50°.

4. The tank (2) according to any of the preceding claims 1 - 3, wherein the first, second and third planes are substantially parallel relatively each other.

5. The tank (2) according to any of the preceding claims 1 - 4, wherein the recesses (15, 25) in the flange (9) are arranged at an edge of the flange (9) in the longitudinal direction (L), so that the flange surface (9a) encloses less or equal to half of the circumference of the recesses (15, 25).

6. The tank (2) according to any of the preceding claims 1 - 5, wherein the baffle wall portion (8) is substantially polygonal, and the flange (9) comprises a recess (25) in each corner of the polygon.

7. The tank (2) according to any of the preceding claims 1 - 5, wherein the baffle wall portion (8) is a superellipse, and the flange (9) comprises a recess (25) where a flange radius is at its minima.

8. The tank (2) according to any of the preceding claims 1 - 7, wherein the flange (9) comprises 4 - 12, preferably 8, distinct recesses (15, 25) in the third plane.

9. The tank (2) according to any of the preceding claims 1 - 8, wherein at least two different two adhesives is used in different adhesive bonds (10); a first adhesive with a first elastic modulus, and a second adhesive with a second elastic modulus.

10. The tank (2) according to claim 9, wherein the second elastic modulus is larger than the first elastic modulus, and the first adhesive is used in the adhesive bonds (10) in stiff parts of the shell (4) and/or the baffle (5) such as in corners or radii minima, and the second adhesive is used in less stiff regions of the shell (4) and/or the baffle (5), such as near the centre of the sides or radii maxima.

11. The tank (2) according to any of the preceding claims 1 - 10, wherein the baffle (5) and the shell (4) are made of different materials with different mechanical properties.

12. The tank (2) according to any of the preceding claims 1 - 11, wherein the tank comprises a second tank baffle (5) and the shell (4) comprises a second set (7) of at least two distinct protrusions (16.26).

13. A vehicle (1), preferably a heavy vehicle such as a truck or a bus, comprising a tank according to any of the preceding claims 1 - 12.

14. Method for manufacturing a fuel tank (2) according to any of the preceding claims 1 - 12, the method comprising the steps of: providing (100) a shell (4), comprising a first set (6) of at least two distinct protrusions (16, 26), each with at least one first shell surface portion (16a, 26a) arranged to extend substantially in a longitudinal direction of the shell (4) and at least one second shell surface portion (16b, 26b) arranged with a first angle ?1relatively the longitudinal direction, providing (110) a baffle (5), with a wall portion (8) extending in a third plane and at least one flange (9) with at least one peripheral flange surface (9a) arranged to at least partly face and abut the inner surface (4a) of the shell (4), the baffle (5) comprising at least two distinct recesses (15, 25), each recess comprises at least one first flange surface portion (15a, 25a) arranged to extend substantially in the longitudinal direction and at least one second flange surface portion (15b, 25b) arranged with a second angle ?2relatively the longitudinal direction, the recesses (15, 25) being arranged at an edge of the flange (9) in the longitudinal direction, so that the flange surface (9a) encloses less or equal to half of the circumference of the recesses (15, 25), adding (120) adhesive to the second flange surface portion (15b, 25b), - inserting (130) the baffle (5) into the shell (4) until the second flange surface portions (15b, 25b) abuts the second shell surface portions (16b, 26b), creating adhesive joints (10) between said surface portions, setting (140) the adhesive joint (10).