Assembly comprising a bladder for a fuel tank

Abstract

The invention relates to an assembly comprising a bladder (3) for a fuel tank, characterised in that the bladder (3) is configured to have a first configuration in which the bladder (3) is wound in on itself so as to confer thereon a first geometric shape which has a first volume, and a second configuration in which the bladder (3) is unwound so as to confer thereon a second geometric shape which has a second volume, the first volume being strictly smaller than the second volume, the assembly further comprising an attachment device configured to attach the assembly to a fuel tank inner wall (2).

Description

SET INCLUDING A BLADDER FOR FUEL TANK Technical field of the invention

[0001] The present invention relates generally to the control of the pressure of fuel vapors in a fuel tank of a fuel storage system for a vehicle with a thermal engine (also called an "internal combustion engine"), in particular, for a motor vehicle. The term "motor vehicle" means any mobile equipment, in particular, vehicles on road, rail, sea, air, space.

[0002] More particularly, the invention relates to an assembly comprising a bladder for a fuel tank for a thermal engine vehicle.

[0003] The invention also relates to an assembly according to the invention comprising a removable holding device.

[0004] The invention also relates to an assembly according to the invention comprising an anti-swaying device.

[0005] The invention also relates to a fuel storage system for a thermal engine vehicle comprising a fuel tank and at least one assembly according to the invention.

[0006] The invention also relates to a use of at least one assembly according to the invention in a fuel tank of a fuel storage system for a vehicle with a thermal engine.

[0007] The invention also relates to a kit for manufacturing a fuel storage system for a thermal engine vehicle comprising an anti-sloshing device and at least one assembly according to the invention.

[0008] The invention also relates to a vehicle with a thermal engine, in particular a motor vehicle, comprising a fuel storage system according to the invention. The invention finds particular application for hybrid vehicles. Hybrid vehicles are vehicles equipped with a thermal engine combined with one or more electric motors.

[0009] The invention also relates to a method for manufacturing a fuel storage system for a thermal engine vehicle comprising a fuel tank and at least one assembly according to the invention.

[0010] The invention also relates to a fuel storage system for a thermal engine vehicle obtained by implementing the manufacturing method according to the invention.

[0011] The invention finally relates to a method of operating a fuel storage system according to the invention.

[0012] The fuel stored in a fuel tank of a fuel storage system for a vehicle with a thermal engine is subject to temperature fluctuations mainly dependent on the outside temperature. Depending on the climate to which the vehicle is exposed, the temperature of the fuel can vary greatly, in particular if the vehicle is outside when it is moving and when it is parked. A rise in temperature of the fuel stored in the fuel tank generates an evaporation of a quantity of it. Since the fuel tank defines a predetermined, closed and sealed volume, the generation of fuel vapors causes a rise in pressure in the gaseous phase inside the fuel tank.High fuel vapor pressure generates mechanical stress on the walls of the fuel tank, which can damage them or even pose a risk of the fuel tank exploding if the pressure increase is not controlled. Technical background of the invention

[0013] It is known in the prior art, for example from document WO 2021 / 013940 A1, to place an inflatable bladder inside a fuel tank. This bladder is connected to an air inlet and outlet duct leaving the fuel tank and allows, alternatively, to supply the bladder with air or to evacuate part of the air contained in the bladder. In this way, depending on the fluctuation in the quantity of fuel vapors in the fuel tank, the bladder can inflate or deflate to modify the volume available for the fuel vapors and thus limit variations in fuel vapor pressure.

[0014] This bladder system does reduce the risk of experiencing pressure spikes in the fuel tank, but it does pose some problems. The relatively large volume of the bladder may be incompatible with the generally complex shape of the fuel tank or, conversely, may require the fuel tank to be shaped and sized to accommodate the bladder. For example, for a 45-litre fuel tank, the inflated bladder must have a volume of approximately 20 litres to have a significant beneficial effect, which requires a sufficiently large and clear area within the fuel tank to accommodate the bladder.In addition, the large volume of the bladder makes its introduction and fixing in the fuel tank complex to implement during the manufacture of the fuel tank, which implies an increase in the cost and manufacturing time of the fuel tank.

[0015] The invention aims in particular to solve the problems identified in the state of the art by limiting the rise in pressure of fuel vapors in the fuel tank and by avoiding or mitigating the disadvantages posed by the bladder of the state of the art and its large volume.

[0016] To this end, the invention relates to an assembly according to a first embodiment comprising a bladder for a fuel tank, characterized in that the bladder is configured to have:

[0017] - a first configuration in which the bladder is rolled up on itself, preferably around an axis X, so as to give it a first geometric shape having a first volume, and

[0018] - a second configuration in which the bladder is unrolled, preferably around the X axis, so as to give it a second geometric shape having a second volume,

[0019] the first volume being strictly less than the second volume,

[0020] the assembly further comprising a fastening device configured to secure the assembly to an internal wall of a fuel tank.

[0021] Thus, the bulky bladder of the prior art is here replaced by a bladder having a reduced volume when it is introduced and fixed in a fuel tank. This makes it easier to introduce the bladder inside a fuel tank through an opening made in a wall of the fuel tank, for example, a bung hole of the fuel tank. Furthermore, thanks to the fixing device, the bladder does not unroll anywhere in the fuel tank but in a predetermined space thereof, a space which did not require having to modify the shape of the fuel tank to receive the bladder. The predetermined space is chosen so that the bladder unrolls without hindrance in the fuel tank and, in the second configuration, does not interfere with the interior of the fuel tank, which could damage the bladder.Regarding the bung hole, it is used for the introduction into the fuel tank of one or more components internal to the fuel tank, for example, a fuel pump to be installed at the bottom of the fuel tank. After installation of the component(s) internal to the fuel tank and before putting the fuel tank into operation, the bung hole is hermetically sealed. In one example, the bung hole has a diameter of 130 mm.

[0022] Advantageously, the bladder is manufactured unrolled, which is its initial shape. Advantageously again, the bladder is manufactured from an elastic material, that is to say a flexible, deformable material that returns to its initial shape when it is no longer mechanically constrained. This allows the bladder thus manufactured to be "rollable". The "rollable" nature of the bladder corresponds to a capacity of the bladder to be able to pass from an unrolled configuration to a rolled configuration, and vice versa, without undergoing major plastic deformation, like a rollable mattress. In one example, the bladder is manufactured from a thermoplastic elastomer material, for example thermoplastic polyurethane (TPU). Thanks to this characteristic, the bladder is not only deformable when it is unrolled, it is also deformable when it is rolled up on itself, for example, in the first configuration, the bladder is still deformable in torsion and / or bending.

[0023] Alternatively, the bladder is made of polyethylene (PE), polyamide (PA), or as a multi-layer material comprising polyethylene (PE), preferably high-density polyethylene (HDPE), and ethylene vinyl alcohol (EVOH).

[0024] Preferably, the polyethylene is high density polyethylene (HDPE), and the polyamide is polyamide 6, 11 or 12 (PA6, PA11 or PA12).

[0025] Advantageously, the multilayer comprises an adhesive layer provided between the polyethylene (PE) layer, preferably high-density polyethylene (HDPE), and the ethylene vinyl alcohol (EVOH) layer.

[0026] Different materials can thus be chosen to make the bladder in order to give it a choice of characteristics, such as low cost, mechanical resistance, flexibility, deformability or impermeability to fuel.

[0027] Furthermore, the fact that the bladder is rolled up on itself in a first configuration allows the bladder to be introduced into the fuel tank after the fuel tank is manufactured and not necessarily during the fuel tank manufacture, which simplifies the fuel tank production line.

[0028] Preferably, the first geometric shape is a generally cylindrical shape.

[0029] Preferably, the second geometric shape is a generally prismatic, cylindrical or spherical shape.

[0030] The second volume is proportional to the volume of fuel in the fuel tank. Advantageously, the second volume is between 20% and 50% of the volume of fuel in which the bladder is immersed, preferably the second volume is between 20% and 30% of the volume of fuel in which the bladder is immersed.

[0031] The bladder can thus be easily sized according to specifications to which the fuel tank must conform. In other words, the shape and volume of the bladder can be easily adapted to take into account the architecture of the fuel tank, which illustrates the flexibility of use of the invention.

[0032] The term "fuel" means a hydrocarbon suitable for powering thermal engines. For particular engines, the fuel may be based on alcohol, for example, ethanol, bioethanol, butanol, methanol, or mixtures thereof, for example with hydrocarbons.

[0033] The term "tank" means a sealed container, capable of storing fuel under various and varied conditions of use and environment. The tank according to the invention comprises a wall, also called a casing, delimiting a hollow body. A tank wall comprises an inner wall and an outer wall. The inner wall faces the interior volume of the hollow body while the outer wall faces the volume outside the hollow body. The hollow body according to the invention is made of metal or plastic, preferably plastic. In the latter case, it comprises at least one synthetic resin polymer present in the solid state under ambient conditions. Hollow bodies made of plastic are preferred due to their greater elasticity and their superior ability to be formed into complex shapes.

[0034] A hollow plastic body can be produced using any known processing method. A known method is the injection process. Extrusion blow molding and rotational molding processes are also known.

[0035] The term "plastic material" refers to both the generally homogeneous material of a single-layer structure and the heterogeneous material of a multi-layer structure.

[0036] The hollow body advantageously comprises at least one thermoplastic polymer, that is to say, a polymer which, under the influence of heat, melts or softens sufficiently to allow it to be shaped.

[0037] The term "polymer" refers to both homopolymers and copolymers (binary or ternary in particular). Examples of such copolymers are, but are not limited to, random distribution copolymers, block copolymers, block copolymers and graft copolymers.

[0038] Any type of thermoplastic polymer or copolymer with a melting temperature below the decomposition temperature is suitable. Thermoplastic polymers with a melting range of at least 10 degrees Celsius (10°C) are particularly suitable. Examples of such materials include those with a polydispersity in their molecular weight.

[0039] In particular, polyolefins, thermoplastic polyesters, polyketones, polyamides and their copolymers may be used. A mixture of polymers or copolymers may also be used, as well as a mixture of polymeric materials with inorganic, organic and / or natural fillers such as, for example, but not limited to, carbon, salts and other inorganic derivatives, natural or polymeric fibers. It is also possible to use multilayer structures consisting of stacked and integral layers comprising at least one of the aforementioned polymers or copolymers.

[0040] A commonly used polymer is polyethylene. Excellent results have been achieved with high-density polyethylene (HDPE).

[0041] In one example, the hollow body comprises a multilayer structure comprising at least one layer of thermoplastic material and at least one additional layer which may advantageously be made of a barrier material to liquids and / or gases. Preferably, the nature and thickness of the barrier layer are chosen so as to limit as much as possible the permeability of liquids and gases in contact with the wall of the tank. Preferably, this layer is based on a barrier material, i.e. a fuel-impermeable resin such as EVOH for example (partially hydrolyzed ethylene-vinyl acetate copolymer). Alternatively, the hollow body may be subjected to a surface treatment (fluorination or sulfonation) with the aim of making it fuel-impermeable.

[0042] Advantageously, a local XYZ reference frame being linked to the bladder, the bladder is wound around an X axis in the first configuration, the bladder is unwound around the X axis in the second configuration and the bladder is configured to have a third configuration in which the bladder is compressed along a Y and / or Z axis so as to give it a third geometric shape having a third volume, the third volume being greater than or equal to the first volume and strictly less than the second volume.

[0043] Thus, when the bladder is in operation inside a fuel tank, the second configuration is a resting configuration of the bladder and the third configuration is a working configuration of the bladder. In the working configuration of the bladder, the bladder is deformed under the effect of the pressure inside the fuel tank. Preferably, the deformation of the bladder is a compression of the bladder along the Y and / or Z axis. The deformation of the bladder may additionally be a compression of the bladder along the X axis.

[0044] The invention also provides an assembly according to a first embodiment as mentioned above, characterized in that the assembly further comprises a removable device for holding the bladder in the first configuration.

[0045] The removable holding device is, for example, an elastic band, a string with a knot, a U-shaped clip or the like.

[0046] This ensures effective bladder retention in the first configuration and easy bladder release.

[0047] The invention also provides an assembly according to a first embodiment as mentioned above, characterized in that the fixing device comprises a member chosen from the group consisting of clipping, snap-fastening, interlocking, gluing, clamping, pinching and welding members, a member configured to fix the assembly to an internal wall of the fuel tank.

[0048] The invention also provides an assembly according to a first embodiment as mentioned above, characterized in that the assembly further comprises an anti-swaying device.

[0049] An anti-slosh baffle is designed to reduce the noise associated with waves created within a fuel tank when a vehicle accelerates sharply, brakes, or corners. This type of device is also known as an anti-slosh baffle.

[0050] In one exemplary embodiment, the anti-sway device is made of plastic, for example, polyoxymethylene (POM).

[0051] Advantageously, the anti-sway device carries the fixing device.

[0052] Advantageously, the anti-sway device is provided with a handle to allow manipulation of the anti-sway device inside the fuel tank, in particular, to fix the anti-sway device inside the fuel tank, for example, at the bottom of the fuel tank. For this purpose, a complementary part of the fixing device is configured to be arranged inside the fuel tank, for example, at the bottom of the fuel tank.

[0053] Preferably, the fixing device is manufactured in one piece with the anti-sway device. More preferably, the complementary part of the fixing device is welded to the bottom of the fuel tank.

[0054] Alternatively, the anti-sway device is provided with a spring device. In this case, the anti-sway device is made of two parts movable relative to each other and connected to each other by the spring device. The spring device is compressed in order to reduce the size of the anti-sway device and facilitate its insertion inside the fuel tank. The anti-sway device is positioned inside the fuel tank at a predetermined location, for example, at the bottom of the fuel tank. The spring device is decompressed in order to bring one movable part of the anti-sway device into abutment against a bottom wall of the fuel tank and the other movable part into abutment against a wall opposite the bottom wall of the tank.In this latter position, the anti-sway device is blocked between the bottom wall of the fuel tank and the wall opposite the bottom wall of the fuel tank. This type of anti-sway device, also called a "spring loaded baffle" in English, is described in document WO 2010 / 029103 A1.

[0055] The invention also provides an assembly according to a second embodiment comprising a bladder for a fuel tank, characterized in that the bladder is configured to have:

[0056] - a first configuration in which the bladder is compressed so as to give it a first geometric shape having a first volume, and

[0057] - a second configuration in which the bladder is decompressed so as to give it a second geometric shape having a second volume,

[0058] the first volume being strictly less than the second volume,

[0059] the assembly further comprising an anti-sway device.

[0060] Thanks to the anti-sloshing device, the assembly not only limits the rise in fuel vapor pressure in the fuel tank, but also reduces the noise associated with the waves that are created within a fuel tank.

[0061] Also provided according to the invention is an assembly according to a second embodiment as mentioned above, characterized in that the assembly further comprises a fixing device configured to fix the assembly to an internal wall of the fuel tank.

[0062] Thanks to the fastening device, the bladder does not unroll anywhere in the fuel tank but in a predetermined space thereof. The predetermined space is chosen so that the bladder unrolls unhindered in the fuel tank and, in the second configuration, does not interfere with the interior of the fuel tank, which could damage the bladder.

[0063] The invention also provides an assembly according to a second embodiment as mentioned above, characterized in that the fixing device comprises a member chosen from the group consisting of clipping, snap-fastening, interlocking, gluing, clamping, pinching and welding members, a member configured to fix the assembly to an internal wall of the fuel tank.

[0064] The invention also provides an assembly according to a second embodiment as mentioned above, characterized in that the bladder is configured to have a third configuration in which the bladder is compressed so as to give it a third geometric shape having a third volume, the third volume being greater than or equal to the first volume and strictly less than the second volume.

[0065] Thus, when the bladder is in operation inside a fuel tank, the second configuration is a resting configuration of the bladder and the third configuration is a working configuration of the bladder. In the working configuration of the bladder, the bladder is deformed under the effect of the pressure inside the fuel tank.

[0066] The invention also provides a fuel storage system for a thermal engine vehicle, comprising:

[0067] - a fuel tank, and

[0068] - at least one assembly conforming to a foregoing assembly extending inside the fuel tank, the fuel storage system being configured to store fuel inside the fuel tank and outside the bladder.

[0069] According to the invention, said at least one assembly extends inside the fuel tank in any configuration of the bladder, whether the first, second or third configuration.

[0070] In the case of a fuel storage system comprising at least one assembly according to the first embodiment as mentioned above, the fuel storage system is characterized in that, in the second configuration of the bladder, the bladder is unrolled, preferably around the X axis, inside the fuel tank.

[0071] Thus, the fuel storage system for a thermal engine vehicle of the prior art is here replaced by a fuel storage system for a thermal engine vehicle comprising at least one assembly comprising a bladder having a reduced volume during its introduction and its fixing inside the fuel tank. The introduction of said bladder inside the fuel tank having been carried out through an opening made in a wall of the fuel tank, opening hermetically closed before the fuel storage system is put into service. In one example, the aforementioned opening is a bung hole of the fuel tank. The assembly can combine a bladder with a removable bladder holding device in the first configuration and / or with an anti-swaying device, said at least one assembly having had a reduced volume during its introduction and its fixing inside the fuel tank.The introduction of said at least one assembly inside the fuel tank having been carried out through an opening provided in a wall of the fuel tank, opening hermetically sealed before the fuel storage system is put into service. In one example, the aforementioned opening is a bung hole of the fuel tank.

[0072] The term "fuel storage system for a vehicle with a thermal engine", also called "fuel system", means any device incorporated in the vehicle with a thermal engine whose function is to store, purify, measure or transport a fuel intended to supply the thermal engine. A fuel system comprises at least one fuel tank and a fuel supply line to the thermal engine. It may also include, in a non-limiting manner, one or more of the following accessories: fuel tank vent valve and line, filler pipe, canister, fuel filter, fuel pump, fuel tank gauge, electrical connector, closing cap as well as any member, in general, through which fuel passes in the liquid or gaseous state, for example, a fuel vapor circulation pipe.

[0073] The fuel storage system according to the invention further comprises a ventilation duct connecting the inside of the bladder to the outside of the fuel tank. In the case where the material of the bladder is impermeable to fuel and fuel vapors, the connection to the outside of the fuel tank opens into the atmosphere, thus the fuel storage system allows, alternatively, to supply the bladder with air or to evacuate part of the air contained in the bladder. In the case where the material of the bladder is permeable to fuel and / or fuel vapors, the connection to the outside of the fuel tank opens into a fuel vapor circulation duct towards a canister, thus the fuel storage system allows, alternatively, to supply the bladder with gas or to evacuate part of the gas contained in the bladder towards the canister.The gas feeding the bladder is either air coming directly from the atmosphere or air passing through the canister.

[0074] Preferably, in the second configuration, when the fuel tank is full of fuel, the bladder is completely submerged in the fuel.

[0075] Advantageously, the fuel storage system further comprises at least one heat storage member, extending inside the fuel tank, comprising a phase change material having a melting point of between 18° and 40°C, the phase change material being preferentially chosen from the following list: calcium chloride hexahydrate (CaCl2.6H2O), octadecane (C 18 H 38 ), cyclohexanol (C6H 12 O), a derivative of glycerin.

[0076] The at least one heat storage member makes it possible to absorb heat, in particular when the fuel has a temperature close to the melting point of the phase change material. Indeed, the fusion reaction being endothermic, it consumes heat from the fuel. The at least one heat storage member thus makes it possible to limit the rise in temperature of the fuel and therefore to limit the generation of fuel vapor in the fuel tank. Thanks to this limitation of the generation of fuel vapor, the bladder can be sized with a smaller volume, so that the disadvantages linked to the volume of the bladder are reduced, in particular the limitation of the useful volume of the tank. It is thus understood that the combined effects of the at least one heat storage member and the bladder surpass the effects provided by the at least one heat storage member and the bladder considered in isolation.

[0077] Advantageously, in the third configuration of the bladder, the bladder of a fuel storage system comprising an assembly according to the first embodiment as mentioned above is compressed along the Y and / or Z axis inside the fuel tank.

[0078] This helps limit the pressure buildup inside the fuel tank by allowing fuel vapors to occupy excess volume inside the fuel tank. The excess volume is provided by the bladder, in the third bladder configuration.

[0079] Additionally, compressing the bladder along the Y and / or Z axis within the fuel tank is more effective in reducing bladder volume. This is because, when the largest dimension of the bladder extends along the X axis, compressing the bladder wall along the Y and / or Z axis provides less resistance to deformation than compressing the bladder along the X axis.

[0080] The invention also provides for the use of at least one assembly, in accordance with a aforementioned assembly, in a fuel tank, the bladder being intended to limit the increase in pressure inside the fuel tank, in order to limit the mechanical stresses on the fuel tank.

[0081] The invention also provides a kit for manufacturing a fuel storage system for a thermal engine vehicle, the system comprising a fuel tank and at least one anti-sloshing device extending inside the fuel tank, the kit is characterized in that it comprises at least one assembly, conforming to a aforementioned assembly, the bladder being carried by the at least one anti-sloshing device.

[0082] Thus, a fuel tank equipped with at least one anti-sway device can easily be transformed into a fuel tank equipped with at least one anti-sway device carrying a bladder of an assembly according to the invention.

[0083] The invention also provides a thermal engine vehicle comprising a fuel storage system in accordance with one of the aforementioned systems.

[0084] A method of manufacturing a fuel storage system for a thermal engine vehicle is also provided, comprising the following steps:

[0085] a) make a fuel tank,

[0086] (b) manufacturing a bladder conforming to the aforementioned bladder,

[0087] c) maintain the bladder in the first configuration,

[0088] (d) insert the bladder inside the fuel tank through an opening in a wall of the fuel tank,

[0089] (e) securing the bladder inside the fuel tank such that the bladder extends inside the fuel tank,

[0090] f) releasing the bladder from the first configuration to the second configuration such that, in the second configuration, the bladder is unwound, preferably around the X axis, inside the fuel tank.

[0091] In one example, step d) of introducing the bladder inside the fuel tank through an opening provided in a wall of the fuel tank is carried out manually by an operator.

[0092] In a preferred embodiment, the unrolled shape of the bladder is the initial shape of said bladder, i.e. its shape at the end of manufacture. In addition, by manufacturing said bladder in an elastic material, a deformation thereof, for example by rolling said bladder on itself, becomes reversible. In this case, the transition from the first configuration to the second configuration is automatic. Indeed, after having released said bladder in step f), i.e. after having removed the mechanical constraint which forced said bladder to remain rolled on itself, it unrolls on its own to completely or almost completely return to its initial shape. In the case where said bladder almost completely returns to its initial shape, it can be helped to completely return to its initial shape by sending a pressurized gas into said bladder, for example pressurized air.

[0093] Advantageously, in the aforementioned method, step e) of fixing the bladder inside the fuel tank is carried out by means of clipping, snap-fastening, fitting, gluing, clamping, pinching or welding the bladder to an internal wall of the fuel tank.

[0094] Preferably, the inner wall of the fuel tank is a bottom wall of the fuel tank.

[0095] Advantageously, in the aforementioned method, step c) of maintaining the bladder in the first configuration is carried out by means of a removable maintaining device.

[0096] The invention also provides a method for manufacturing a fuel storage system for a thermal engine vehicle, comprising the following steps:

[0097] a) make a fuel tank,

[0098] (b) manufacture at least one assembly conforming to one of the aforementioned assemblies,

[0099] c) maintain the bladder in the first configuration,

[0100] (d) introducing the at least one assembly inside the fuel tank through an opening made in a wall of the fuel tank,

[0101] e) securing the at least one assembly inside the fuel tank such that the at least one assembly extends inside the fuel tank,

[0102] f) releasing the bladder to move it from the first configuration to the second configuration inside the fuel tank.

[0103] In one example, step d) of introducing the at least one assembly inside the fuel tank through an opening provided in a wall of the fuel tank is carried out manually by an operator.

[0104] In the case of a fuel storage system comprising at least one assembly according to the first embodiment as mentioned above, step f) of releasing the bladder in order to make it pass from the first configuration to the second configuration is carried out in such a way that, in the second configuration, the bladder is unwound, preferably around an axis X, inside the fuel tank.

[0105] In a preferred embodiment, the unrolled shape of the bladder is the initial shape of the bladder, i.e. its shape at the end of manufacture. In addition, by manufacturing said bladder in an elastic material, a deformation thereof, for example by rolling said bladder on itself, becomes reversible. In this case, the transition from the first configuration to the second configuration is automatic. Indeed, after releasing said bladder in step f), i.e. after removing the mechanical constraint which forced said bladder to remain rolled on itself, it unrolls on its own to completely or almost completely return to its initial shape. In the case where said bladder almost completely returns to its initial shape, it can be helped to completely return to its initial shape by sending a pressurized gas into said bladder, for example pressurized air.

[0106] Advantageously, in the aforementioned method, step e) of fixing the at least one assembly inside the fuel tank is carried out by means of clipping, snap-fastening, fitting, gluing, clamping, pinching or welding the at least one assembly to an internal wall of the fuel tank.

[0107] Preferably, the inner wall of the fuel tank is a bottom wall of the fuel tank.

[0108] Preferably, in the case of clamping the at least one assembly on a bottom wall of the fuel tank, said clamping is carried out by means of a spring device as described previously, such that said at least one assembly is blocked between the bottom wall of the fuel tank and a wall opposite the bottom wall of the fuel tank.

[0109] Advantageously, in the aforementioned method, step c) of maintaining the bladder in the first configuration is carried out by means of a removable maintaining device.

[0110] The invention also provides a fuel storage system for a vehicle with a thermal engine, characterized in that it is obtained by implementing an aforementioned manufacturing method.

[0111] Finally, according to the invention, there is provided a method of operating a fuel storage system in accordance with one of the aforementioned systems, characterized in that the method comprises, in response to an increase in the pressure inside the fuel tank, a step of deforming the bladder to pass from the second configuration to the third configuration.

[0112] The step of deforming the bladder to move from the second configuration to the third configuration is achieved by the sole increase in pressure inside the fuel tank.

[0113] Other features and advantages of the invention will become clear from the description given below, for information purposes only and in no way limiting, with reference to the appended drawings, in which:is an exploded perspective view of the main constituent elements of a fuel storage system according to the invention, in which the bladder is shown in the second configuration;is a view similar to the, in which the bladder is shown in the first configuration;is a view similar to the, in which the bladder is shown at the start of its coupling to the fuel tank;Figures 4 to 13 are sectional views along the plane T of the fuel tank of the, in which the bladder is shown in different successive positions of coupling to the fuel tank;is a perspective view of a vehicle with a thermal engine according to the invention.Detailed description of at least one embodiment of the invention

[0114] In the various figures, identical or similar elements bear the same references, possibly with the addition of an index. The description of their structure and function is therefore not systematically repeated.

[0115] In all that follows, the orientations are the orientations of the figures. In particular, the terms "upper", "lower", "left", "right", "above", "below", "forward" and "backward" are generally understood in relation to the direction in which the figures are represented.

[0116] Figures 1 and 2 illustrate the main constituent elements of a fuel storage system 1 according to the invention.

[0117] Among the main constituent elements of the fuel storage system 1 are a fuel tank 2 and a bladder 3.

[0118] The fuel tank 2, generally made of plastic, is configured to store the fuel that is used by the thermal engine vehicle, in particular for its propulsion, inside the fuel tank 2 and outside the bladder 3. The fuel tank 2 comprises a wall delimiting a hollow body defining an interior volume in which the fuel is stored both in liquid form and in gaseous form, according to a distribution depending in particular on the pressure and temperature conditions inside the fuel tank 2. The fuel tank generally comprises a filling duct, allowing the tank to be filled with fuel, a ventilation duct allowing the fuel vapors to be evacuated under certain conditions and an injection duct allowing the fuel to be conveyed to the engine of the thermal engine vehicle.These three conduits are well known in the state of the art, so they are not shown in the figures and will not be described further in the following.

[0119] The bladder 3 comprises an elastically deformable wall allowing it to unroll and roll up without it deforming plastically. The bladder is manufactured here unrolled, that is its initial shape, in an elastic material, that is to say a flexible, deformable material which returns to its initial shape when it is no longer mechanically constrained. In one example, the bladder is manufactured in a thermoplastic elastomer material, for example thermoplastic polyurethane (TPU).

[0120] In another example, the bladder is made of polyethylene (PE), polyamide (PA), or in the form of a multilayer comprising polyethylene (PE) and ethylene vinyl alcohol (EVOH). Preferably, the polyethylene is high-density polyethylene (HDPE), the polyamide is polyamide 6, 11 or 12 (PA6, PA11 or PA12), and the multilayer comprises an adhesive layer provided between a layer of high-density polyethylene and the layer of ethylene vinyl alcohol. Advantageously, the multilayer comprises an adhesive layer provided between the layer of polyethylene (PE), preferably high-density polyethylene (HDPE), and the layer of ethylene vinyl alcohol (EVOH).

[0121] According to the invention, the bladder 3 is configured to have a first configuration and a second configuration. In the first configuration, the bladder 3 is wound on itself around an axis X so as to give the bladder 3 a first geometric shape having a first volume (see). In the illustrated example, the first geometric shape is a generally cylindrical shape. In the second configuration, the bladder 3 is unwound around the axis X so as to give the bladder 3 a second geometric shape having a second volume (see). In the illustrated example, the second geometric shape is a generally prismatic shape. Alternatively, the second geometric shape is a generally cylindrical or spherical shape (not shown). In all cases, the first volume is strictly less than the second volume.

[0122] In practice, the second volume is proportional to the volume of fuel in the fuel tank 2. Advantageously, the second volume is between 20% and 50% of the volume of fuel in which the bladder 3 is immersed, preferably the second volume is between 20% and 30% of the volume of fuel in which the bladder 3 is immersed.

[0123] The maximum volume of the bladder 3 is chosen according to the volume and shape of the fuel tank 2, the range of values ​​proposed being able to be adapted to certain types of motor vehicle tanks.

[0124] The X axis is part of a local XYZ reference frame linked to the bladder 3. The bladder 3 is configured to have a third configuration. In the third configuration, the bladder 3 is compressed along the Y and / or Z axis so as to give it a third geometric shape having a third volume (not shown). The third volume is greater than or equal to the first volume and strictly less than the second volume.

[0125] In Figures 1 and 2, the bladder 3 is not yet coupled to the fuel tank 2.

[0126] Illustrates the start of the introduction of the bladder 3 inside the fuel tank 2 through an opening 6, i.e. the start of its coupling to the fuel tank 2. The opening 6 is a bung hole of the fuel tank.

[0127] Figures 4 to 13 illustrate different successive positions of the bladder 3 in the fuel tank 2 up to the final position, i.e. the position in which the coupling of the bladder 3 to the fuel tank 2 is completed.

[0128] As visible in Figures 11 and 12, the bladder 3 is part of an assembly further comprising a fixing device configured to fix the assembly to an internal wall of the fuel tank 2. The fixing device comprises a member chosen from the group consisting of clipping, snap-fastening, interlocking, gluing, clamping, pinching and welding members, a member configured to fix the assembly to an internal wall of the fuel tank 2. The assembly also comprises a removable holding device 4 for the bladder 3 in the first configuration, here a string with a knot, and an anti-swaying device 5 carrying the bladder 3. In one example, the anti-swaying device 5 is made of plastic, for example, polyoxymethylene (POM).

[0129] Alternatively to the string with a knot, the removable holding device 4 is an elastic band or a clip, for example, a U-shaped clip (not shown).

[0130] Figures 1 to 13 also illustrate steps of a method for manufacturing a fuel storage system 1 for a thermal engine vehicle comprising the aforementioned assembly. The method comprises the following steps:

[0131] a) manufacture a fuel tank 2 (illustrates the fuel tank 2 as manufactured),

[0132] (b) manufacture the aforementioned assembly (illustrates the aforementioned assembly as manufactured),

[0133] c) maintaining the bladder 3 in the first configuration (illustrates the aforementioned assembly in which the bladder 3 is maintained in the first configuration),

[0134] d) introducing the assembly inside the fuel tank 2 (figures 3 to 11 illustrate different steps of introduction inside the fuel tank 2 of the aforementioned assembly in which the bladder 3 is held in the first configuration), the introduction of the aforementioned assembly being carried out through the opening 6 made in a wall 7 of the fuel tank 2 (see),

[0135] e) securing the assembly inside the fuel tank 2 such that the assembly extends inside the fuel tank 2 (illustrates the aforementioned assembly in the secured position),

[0136] f) releasing the bladder 3 to move it from the first configuration to the second configuration such that, in the second configuration, the bladder 3 is unwound around the X axis inside the fuel tank 2 (illustrates the bladder unwound around the X axis inside the fuel tank 2).

[0137] Material interferences between the aforementioned assembly and the opening 6 are visible in Figures 3 to 10, these interferences are due to the fact that the bending deformation of the assembly is not illustrated in these figures. Indeed, in the fuel tank 2 as illustrated, the passage of the opening 6 through the aforementioned assembly requires bending the latter.

[0138] Step c) of holding the bladder 3 in the first configuration is carried out by means of a removable holding device 4, here a string with a knot.

[0139] Step e) of fixing the assembly inside the fuel tank 2 is carried out by means of a fixing device, here comprising a clipping member 8, of the assembly on an internal wall of the fuel tank 2 (illustrates the assembly before clipping while illustrates the assembly after clipping).

[0140] In the illustrated example, the clipping member 8 is a female part of a clip. The female part of the clip is carried by the anti-sway device 5 which also comprises a handle 9 to facilitate the handling of the anti-sway device 5 inside the fuel tank 2, in particular, to fix by clipping the anti-sway device 5 to the bottom of the fuel tank 2. For this purpose, the male part of the clip is arranged at the bottom of the fuel tank 2. Preferably, the female part of the clip is manufactured in one piece with the anti-sway device 5 and the male part of the clip is welded to the bottom of the fuel tank 2.

[0141] Alternatively to the fixing device comprising the clipping member 8, the fixing of the assembly inside the fuel tank 2 is carried out by means of a fixing device comprising a member for snapping, fitting, gluing, clamping, pinching or welding the assembly onto an internal wall of the fuel tank 2 (means not shown).

[0142] Step f) of releasing the bladder 3 here consists of untying the string.

[0143] Illustrates a fuel storage system 1 for a thermal engine vehicle obtained by implementing the aforementioned manufacturing method, system comprising a fuel tank 2 and the aforementioned assembly. The aforementioned assembly extends inside the fuel tank 2. In the second configuration, the bladder 3 is unwound around the X axis inside the fuel tank 2. In the third configuration, the bladder 3 is compressed along the Y and / or Z axis inside the fuel tank 2 (configuration not shown).

[0144] The use of the bladder 3 in the fuel tank 2 of the fuel storage system 1 for a thermal engine vehicle serves to limit the increase in pressure inside the fuel tank 2.

[0145] Indeed, when the fuel contained inside the fuel tank 2 rises in temperature, for example when the outside temperature becomes higher than the temperature of the fuel, part of the fuel is evaporated, which generates fuel vapors in the fuel tank 2. Given that the fuel tank 2 defines a closed and sealed volume, the increase in the quantity of fuel vapors causes the pressure in the gaseous phase inside the fuel tank 2 to increase. We will now describe how the fuel storage system 1 according to the invention makes it possible to limit this increase in pressure.

[0146] The bladder 3 is compressed under the action of the pressure in the gas phase inside the fuel tank 2. The wall of the bladder 3 being deformable, a balance of the stresses applied to the wall of the bladder 3 is established, this balance leads to the evacuation of all or part of the air contained in the bladder 3 by a ventilation duct 10. The ventilation duct 10 is connected, on one side, to the bladder 3, more precisely, to the interior volume of the bladder 3 via a first connection of the ventilation duct 10, and, on the other side, to the outside of the fuel tank 2 via a second connection 11 of the ventilation duct 10. In this way, the volume of the bladder 3 extending into the fuel tank 2 decreases, and the volume occupied by the fuel vapors increases, which results in a decrease in the fuel vapor pressure.When the fuel temperature eventually decreases, for example when the outside temperature becomes lower than the fuel temperature, some of the fuel vapors condense. The amount of fuel vapors in the fuel tank 2 then decreases, as does the fuel vapor pressure. A new equilibrium of the stresses on the wall of the bladder 3 is established, this equilibrium leading to a filling of the bladder 3 by the ventilation duct 10 and to an increase in the volume of the bladder 3 extending into the fuel tank 2. Although the ventilation duct 10 is not illustrated in all the figures, it is connected to the bladder 3 before the introduction of the bladder 3 inside the fuel tank 2. The ventilation duct 10 is made of a flexible material allowing it to be deformed with the bladder 3 during its introduction inside the fuel tank 2.

[0147] Thus, when the bladder 3 is in operation inside the fuel tank 2, the bladder 3 deforms in response to an increase in pressure inside the fuel tank 2 causing the bladder 3 to change from the second to the third configuration. The aforementioned deformation is part of a method of operation of the aforementioned fuel storage system 1.

[0148] In an alternative embodiment (not shown), the aforementioned assembly is replaced by the bladder 3 alone. In another alternative embodiment (not shown), the bladder 3 is coupled to one and / or the other of the removable holding device 4 and anti-balloting device 5.

[0149] Figures 1 to 13 finally illustrate a kit for manufacturing a fuel storage system 1 for a vehicle with a thermal engine. The fuel storage system 1 for a vehicle with a thermal engine comprises a fuel tank 2 and an anti-sway device 5 extending inside the fuel tank 2. The kit comprises the aforementioned assembly, the bladder 3 being carried by the anti-sway device 5.

[0150] Illustrates a vehicle 20 with a thermal engine comprising the aforementioned fuel storage system 1. List of references

[0151] 1: fuel storage system2: fuel tank3: bladder4: removable holding device5: anti-sway device6: opening7: wall8: clip9: handle10: ventilation duct11: ventilation duct connection20: vehicle

Claims

Assembly comprising a bladder (3) for a fuel tank, characterized in that the bladder (3) is configured to have:a first configuration in which the bladder (3) is rolled up on itself so as to give it a first geometric shape having a first volume, anda second configuration in which the bladder (3) is unrolled so as to give it a second geometric shape having a second volume, the first volume being strictly less than the second volume, the assembly further comprising a fixing device configured to fix the assembly to an internal wall of the fuel tank (2). Assembly according to claim 1, characterized in that, a local reference XYZ being linked to the bladder (3), the bladder (3) is wound around an X axis in the first configuration, the bladder (3) is unwound around the X axis in the second configuration and the bladder (3) is configured to have a third configuration in which the bladder (3) is compressed along a Y and / or Z axis so as to give it a third geometric shape having a third volume, the third volume being greater than or equal to the first volume and strictly less than the second volume. Assembly according to claim 1 or 2, characterized in that the fixing device comprises a member chosen from the group consisting of clipping, snap-fastening, interlocking, gluing, clamping, pinching and welding members, a member configured to fix the assembly to an internal wall of the fuel tank (2). Assembly according to any one of the preceding claims, characterized in that it further comprises an anti-swaying device (5). Assembly comprising a bladder (3) for a fuel tank, characterized in that the bladder (3) is configured to have:a first configuration in which the bladder (3) is compressed so as to give it a first geometric shape having a first volume, anda second configuration in which the bladder (3) is decompressed so as to give it a second geometric shape having a second volume, the first volume being strictly less than the second volume, the assembly further comprising an anti-swaying device (5). Assembly according to the preceding claim, characterized in that it further comprises a fixing device configured to fix the assembly to an internal wall of the fuel tank (2). Assembly according to the preceding claim, characterized in that the fixing device comprises a member chosen from the group consisting of clipping, snap-fastening, interlocking, gluing, clamping, pinching and welding members, a member configured to fix the assembly to an internal wall of the fuel tank (2). Assembly according to any one of claims 5 to 7, characterized in that the bladder (3) is configured to have a third configuration in which the bladder (3) is compressed so as to give it a third geometric shape having a third volume, the third volume being greater than or equal to the first volume and strictly less than the second volume. Fuel storage system (1) for a thermal engine vehicle, comprising:- a fuel tank (2), and- at least one assembly according to any one of the preceding claims extending inside the fuel tank (2), the fuel storage system being configured to store fuel inside the fuel tank and outside the bladder (3). Fuel storage system (1) according to the preceding claim, characterized in that the system further comprises a ventilation duct (10) connecting the interior of the bladder (3) to the exterior of the fuel tank (2). Use of at least one assembly according to any one of claims 1 to 8 in a fuel tank (2) of a fuel storage system (1) for a thermal engine vehicle, the bladder (3) being intended to limit the increase in pressure inside the fuel tank (2). Kit for manufacturing a fuel storage system (1) for a thermal engine vehicle, the system comprising a fuel tank (2) and at least one anti-sway device (5) extending inside the fuel tank (2), kit characterized in that it comprises at least one assembly according to any one of claims 1 to 8, the bladder (3) being carried by the at least one anti-sway device (5). Vehicle (20) with a thermal engine comprising a fuel storage system (1) according to claim 9 or 10. Method for manufacturing a fuel storage system (1) for a vehicle with a thermal engine, comprising the following steps: a) manufacturing a fuel tank (2), b) manufacturing at least one assembly according to any one of claims 1 to 8, c) maintaining the bladder (3) in the first configuration, d) introducing the at least one assembly inside the fuel tank (2) through an opening (6) provided in a wall (7) of the fuel tank (2), e) fixing the at least one assembly inside the fuel tank (2) such that the at least one assembly extends inside the fuel tank (2), f) releasing the bladder (3) in order to make it pass from the first configuration to the second configuration inside the fuel tank (2). Method for manufacturing a fuel storage system (1) for a thermal engine vehicle according to claim 14, in which step e) of fixing the at least one assembly inside the fuel tank (2) is carried out by means of clipping (8), snap-fastening, nesting, gluing, clamping, pinching or welding the at least one assembly on an internal wall of the fuel tank (2). Method for manufacturing a fuel storage system (1) for a thermal engine vehicle according to claim 14 or 15, in which step c) of holding the bladder (3) in the first configuration is carried out by means of a removable holding device (4). Fuel storage system (1) for a thermal engine vehicle, characterized in that it is obtained by implementing a manufacturing method according to any one of claims 14 to 16.

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