FR3059418B1 - LIQUID STORAGE SYSTEM COMPRISING AN INTEGRATED GAUGE ENCLOSURE, AND AIRCRAFT - Google Patents

Abstract

The present invention relates to a storage system (10) which is provided with an envelope (15) delimiting an internal space (12) for containing a liquid (14), said envelope (15) comprising an inner wall (16). A gauging device (30) comprises at least two flexible capacitive sensors (31) each secured to said inner wall (16), each capacitive sensor (31) emitting a signal (33) representing a level of said liquid in a detection zone of this capacitive sensor (31), said capacitive sensors (31) being distant from each other.

Description

Liquid storage system comprising an integrated gauge envelope, and aircraft

The present invention relates to a liquid storage system comprising an integrated gauge envelope, a vehicle provided with this reservoir, and the gauging method applied. In particular, the storage system may include a fuel tank. The invention is in the field of fuel gauging systems, and in particular vehicle gauging systems. Such a vehicle may especially be an aircraft, and possibly a rotorcraft.

A vehicle having a fuel engine usually has a fuel tank for the engine. In addition, the vehicle may include a gauging system for measuring the amount of fuel contained in the tank, namely the mass and / or the volume of fuel contained.

A first gauging system is provided with a float connected to a position sensor.

A second gauging system comprises an ultrasonic system provided with a transmitter and an ultrasonic receiver.

A third gauging system includes an optical system.

A fourth gauging system comprises a capacitive probe. An aircraft capacitive sensor used to evaluate a quantity of fuel is conventionally referred to as a "gauging cane".

A gauging rod is thus inserted into a tank containing fuel and air. The gauging rod comprises a capacitor provided with two metal frames. For example, the gauging cane has two concentric metal tubes which respectively form an outer frame surrounding an inner frame. The outer frame and the inner frame are radially separated from each other by an internal space.

In addition, the outer frame is provided with at least one opening for communicating the internal space of the gauging rod with the interior of the tank. When the gauging rod is immersed in a tank containing fuel, this fuel enters the internal space via the openings of the outer frame.

The capacitance of the capacitor varies according to the dielectric permittivity of the medium present in the internal space. This dielectric permittivity thus depends on the dielectric permittivity of the fuel in the immersed part of the gauging rod and the dielectric permittivity of the air above this immersed part. Since the dielectric permittivity of a fuel is much greater than the dielectric permittivity of the air, the dielectric permittivity of the medium present in the internal space of the gauging rod varies substantially as the fuel level between the reinforcements varies.

Thus, when the fuel level between the capacitor plates varies, the dielectric permittivity of the medium present in the internal space of the gauging rod varies, and therefore the electrical capacity of the gauging rod varies. The height of the fuel present between the metal reinforcements of the gauging rod can then be deduced from this electrical capacitance. For this purpose, the capacitor can be electrically powered by an alternating electric current to emit a level signal which is a function of the capacitance of the capacitor, and therefore of the fuel level.

The volume of the fuel present in the tank can then be deduced from this level signal according to various parameters. On an aircraft, a mathematical relation can for example give this volume of fuel as a function of the geometry of the tank, the angle of pitch of the aircraft, the angle of roll of the aircraft, and accelerations undergone. by the aircraft. The fuel mass is obtained from the fuel volume and the density of the fluid used.

The gauging rods installed in the usual tanks are sufficiently precise in terms of regulatory requirements.

However, depending on the location of the gauging rod and the geometry of the reservoir, the measurements made by a gauging can may have a degraded accuracy for certain inclinations in roll and / or pitch of the reservoir. A risk of under-gauging or over-gauging is possible with some tanks and with particular attitudes of this tank.

In another aspect, as a gauging rod comprises capacitive probes immersed in the tank, each gauging rod is adapted to a particular tank, particularly in terms of attachment in the tank as well as depending on the shape of the tank. In addition, each new gauging rod must then be certified by the relevant aeronautical authorities in order to meet safety and measurement accuracy criteria.

In particular, a gauging rod with metal tubes must not damage the tank in the event of a crash. Thus, the tubes of a gauging can may have a fuse zone to break in case of a crash to reduce the risk of perforation of the tank.

In addition, the arrangement of a gauging rod in a flexible tank can be tricky. Without particular provision, a flexible tank may tend to deform, and may damage for example a gauging rod arranged in the tank.

The document FR2672389 describes a gauging system provided with optical sensors.

FR2892508 discloses a capacitive gauge which is provided with a measuring capacitor and a reference capacitor and a standard capacitor.

The document FR2908511 describes a gauging system comprising means indicative of the height of the liquid, means indicative of the pitch angle of the tank and / or means indicative of the roll angle of the tank. A calculator calculates the volume of liquid according to a predetermined relationship having as parameters at least said height as well as said pitch angle and / or said roll angle.

The object of the present invention is therefore to propose a storage system for containing a liquid, and in particular fuel, this storage system comprising a gauging device tending to limit the risks of over-gauging or under-gauging.

According to the invention, a storage system is provided with an envelope delimiting an internal space intended to contain a liquid, this envelope comprising an internal wall facing the internal space, the storage system comprising a gauging device for estimating the amount of liquid contained in the envelope.

The gauging device comprises at least two flexible capacitive sensors each secured to said inner wall, each capacitive sensor emitting a signal representing a level of said liquid in a detection zone of this capacitive sensor, said capacitive sensors being distant from each other.

For example, at least three flexible capacitive sensors are each secured to said inner wall, each capacitive sensor emitting a signal representing a level of said liquid in a detection zone of this capacitive sensor, said capacitive sensors being distant from each other.

The detection zone of a capacitive sensor is advantageously distinct from the detection zone of another capacitive sensor.

Optionally, the gauging device comprises a computer connected to each capacitive sensor for making a first estimate of said quantity as a function of said signals.

The term "solidarized" means that a capacitive sensor is disposed in or against the inner wall. A capacitive sensor is thus for example either an integral part of a tank shell, or carried by the inner wall.

Optionally, the first estimate can be made based on said signals only. The expression "based on said signals only" means that the signals emitted by the capacitive sensors represent the only variables used to determine the quantity of liquid, namely the volume and / or the mass of the liquid. These variables are injected into a mathematical model by the calculator to deduce the amount of liquid.

This mathematical model can take various forms such as a database providing information on the quantity of liquid as a function of the measurements made by the capacitive sensors, a mathematical law, a series of operations performed by the calculator, etc.

In this context, the gauging device comprises capacitive sensors that equip an envelope. Such an envelope may represent a reservoir pre-equipped with several flexible capacitive sensors.

Such capacitive sensors may for example be of the type known under the trademark Kapflex®, or described in document WO 2009/122061 for example.

A capacitive sensor may have the advantage of being traversed by a low intensity electric current. As a result, such a sensor can be arranged in or near a fuel. In addition, the flexibility of the capacitive sensor also allows it to be folded and therefore to be integrated in a flexible envelope. In addition, these capacitive sensors are light which allows to arrange several without significantly burdening the storage system.

In addition, an electrical power supply beam and measured data transmissions equip one end of each capacitive sensor. The beams are then connected to a computer. This calculator comprises a subset of electric power transmission and a computer for calculating the level of liquid in the envelope. Therefore, each capacitive sensor has an electrical capacitance which varies according to the height of the liquid near this capacitive sensor. When the height of the liquid in the envelope varies, the capacitance of the capacitive sensor varies, and the electrical signal transmitted by the capacitive sensor to the computer varies. A capacitive sensor therefore has a mode of operation similar to the operation of a gauging rod.

By providing at least two capacitive sensors on the envelope itself, the gauging device makes it possible to estimate the position of the liquid surface plane from the measurements made by the set of capacitive sensors, possibly only with these measurements, and 'deduce the amount of liquid. The surface plane represents the surface of the liquid in contact with the ambient air in the internal space. One such a surface plane of the liquid is referred to as "level line" for convenience and by analogy with a water line of a pool for example.

A rotorcraft often has a relatively low roll angle. Therefore, by arranging two capacitive sensors distant from each other along the roll axis, the invention can provide relatively accurate results.

The measurement signals emitted by the capacitive sensors may be sufficient for calculating the volume and / or mass of the liquid contained in the envelope. The use of pitch angle and roll measurements as well as acceleration is no longer imperative. On a vehicle, the data of the attitude of the vehicle, its acceleration or engine data (s) are no longer essential because the measurements from the capacitive sensors arranged on or in the inner wall become necessary and possibly sufficient in themselves for calculate the volume and / or the mass of the onboard liquid. Optionally, the gauging device may comprise a compensator or a density sensor for deriving the mass of the liquid from the volume of liquid.

By using at least three capacitive sensors, the accuracy of the gauging device is increased. The current estimated position of the surface plane is actually more precise.

By using at least four capacitive sensors, the fault detection of a capacitive sensor is facilitated which makes it possible to secure the gauging device.

Compared to a system using a gauging rod, the invention may have various advantages.

Indeed, an envelope can be pre-equipped with flexible capacitive sensors. Therefore, the arrangement of the gauging device on a vehicle is in fact facilitated.

In addition, the capacitive sensors can be integrated into the envelope. This possible integration of the capacitive sensors in a reservoir further itself allows a table mounting of the storage system. The skins materialized by the envelope can be delivered already equipped with a part of the gauging device. Such a method is absolutely not possible with a gauging can which on the one hand can perforate and / or damage the tank because of its rigidity and, on the other hand, be damaged in itself. because of its rigidity.

These advantages result in time savings in the assembly line of a vehicle, and optimization of the costs of the storage system.

Moreover, the arrangement of at least two or even at least three capacitive sensors on or in the inner wall as such, and not in the middle of the internal space can significantly improve the accuracy of the estimation of the amount of liquid.

In another aspect, the use of flexible capacitive sensors may tend to reduce the risk of perforation of the envelope in case of an accident, compared to a system equipped with rigid gauging rods.

In addition, the storage system may be devoid of a platen carrying a gauging cane.

Furthermore, the gauging device optionally comprises a display connected to the computer. This display shows the value of the estimated liquid quantity.

This quantity can take the form of a volume of the liquid possibly expressed in liter (s), or a mass possibly expressed in kilogram (s).

The storage system may further include one or more of the following features.

Thus, the envelope can be flexible, the envelope being reversibly foldable by an operator to be mounted in a reservoir compartment or unfolded to be extracted from said reservoir compartment. The envelope can thus represent a flexible collapsible reservoir and equipped with gauges, namely capacitive sensors. The invention can indeed be used to equip outside a vehicle a flexible tank, unlike solutions cane that present risks of perforation for example.

In another aspect, the inner wall may comprise a plurality of faces, two adjacent faces meeting at a corner of the envelope, at least one of said sensors may be arranged on a corner.

Capacitive sensors are thus distributed for example in the corners of the envelope to optimize the measurement of the amount of liquid. This arrangement tends to reduce the risk of oversampling or under-gauging.

In another aspect, the envelope may comprise a bottom surmounted by the inner wall, at least one of the capacitive sensors may be secured to the bottom and to said inner wall.

A tank usually has a substantially planar bottom, a side inner wall that extends in elevation from the bottom and a substantially planar ceiling. A capacitive sensor of the invention can thus extend in elevation on the inner wall and on the bottom.

Thus, the bottom of the envelope can also be equipped with flexible capacitive sensors.

By arranging a capacitive sensor on the bottom of the casing and on its inner wall, the invention can make it possible to measure the level line of the liquid, even when the casing has tilting angles which usually make it difficult to measure properly.

The installation of capacitive sensors in the bottom of the tank allows to refine the measurements.

According to another aspect, at least one of said capacitive sensors may be embedded in said inner wall, and optionally optionally in the bottom of the envelope.

Some capacitive sensors do not necessarily need to be in contact with the liquid to measure a height of this liquid. Such a capacitive sensor can thus be integrated into the envelope, being arranged between two layers of the envelope, at least locally.

Alternatively or additionally, the envelope comprises at least one fastening system for a capacitive sensor, this fixing system holding the associated capacitive sensor against the inner wall in a predetermined position. The envelope comprises, for example, as many fixing systems as capacitive sensors, each fixing system fixing a single capacitive sensor against the inner wall. A fixing system can guarantee the absence of folds of the capacitive sensor on itself, and of course a good reading of the liquid level.

A fastening system may for example comprise a guide secured to the inner wall in which the capacitive sensor is slid. As an example of mounting, each corner of a tank shell is equipped with a slide, each capacitive sensor being slid into a slide.

Another alternative or complementary attachment system may comprise at least one link, for example a link provided with a system with loops and hooks. In one embodiment, an upper attachment system and a lower attachment system hold a capacitive sensor in position. The upper fastening system and the lower fastening system then ensure the maintenance of the capacitive sensor possibly in a strict vertical position when the envelope is mounted in a compartment.

In another aspect, the storage system may include a first measurement unit for measuring at least one roll or pitch angle of the envelope, the storage system may include a second measurement unit for measuring at least one acceleration of the envelope, the first measurement unit and the second measurement unit are for example connected to the computer. Therefore, the computer can perform at least one verification of the first estimate using said at least one roll angle or pitch and said at least one acceleration, the computer being connected to an alert system to generate a alert based on at least one predetermined criterion applied during said verification.

The storage system can estimate the amount of liquid contained in the envelope by soliciting the capacitive sensors, and for example only the capacitive sensors.

On the other hand, the attitude angles and accelerations experienced by the envelope can be used to control the accuracy of the first estimate. For example, a verification calculation made from the first estimation of the quantity of liquid associated with the acceleration and attitude of the helicopter in real time must lead to results that correspond to those obtained by the capacitive sensors. . For example, the position within the envelope of a surface plane of the liquid is determined using the capacitive sensors and the verification calculation. If a difference between the two positions does not belong to a margin of error previously established, the gauging device deduces the presence of an error in the measurements made by the capacitive sensors.

In another aspect, an aircraft may be provided with a storage system according to the invention, in particular for containing fuel. The invention also relates to a method for gauging a quantity of liquid in a storage system according to the invention.

This method comprises the following steps: measuring a piece of information relating to a height of liquid with each of said capacitive sensors, each capacitive sensor providing information relating to a height of the liquid in a measurement zone of said internal space, determination of a first estimate of the amount of liquid using said information and a predetermined mathematical model. The expression "measurement of information relating to a height" refers to the signal emitted by a capacitive sensor, this signal varying according to said height.

Each capacitive sensor thus emits a relative signal at the level of the liquid near this capacitive sensor. The calculator of the gauging device then processes the received signals to estimate the quantity of liquid through a mathematical model, this mathematical model being qualified as the first mathematical model for convenience. The first mathematical model thus makes it possible to deduce the quantity of liquid from the information transmitted by the capacitive sensors, with regard to the geometry of the envelope.

This first mathematical model can take various forms such as a database providing the current position of the liquid according to the measurements made by the capacitive sensors, a mathematical law, a series of operations performed by the computer, etc. The determination step of said first estimate may comprise the following steps: - estimation of a current position of a surface plane in which the surface of said liquid in said envelope is contained by using said measured heights and a predetermined mathematical model, - determination of said first estimating using said current position and a predetermined mathematical model.

For example, each capacitive sensor emits an electrical signal under a voltage that varies with the height of the liquid near the capacitive sensor. The computer deduces a height information used to determine the position of the surface plane called "current position".

During a first calculation, the computer is then able to estimate the position of the surface plane of the liquid embedded in the envelope. The architecture of the envelope deployed in the vehicle being stored in a memory unit of the computer, a second calculation then makes it possible to estimate with the same precision the volume and / or the mass of the liquid via a predetermined mathematical model. This predetermined mathematical model can be called "second mathematical model". In addition, the second mathematical model can take various forms such as a database providing information on the quantity of liquid as a function of the current position of the liquid, a mathematical law, a series of operations performed by the calculator, etc.

Furthermore, the method may comprise the following verification steps: - measurement of at least one roll angle or pitch of the envelope, - measurement of at least one acceleration of the envelope, - determination of a position theoretical of the surface plane using said at least one measured roll or pitch angle as well as said at least one measured acceleration. By way of example, the capacitive sensors make it possible to estimate that the surface plane is in a current position in the aircraft's reference frame and that the envelope contains 300 liters of fuel.

During the verification step, the computer determines a theoretical position of the surface plane reached by a fuel volume of 300 liters with the roll angle and / or measured pitch and measured accelerations. This calculation can be performed using a predetermined mathematical model and stored. For example, the surface plane has in the theoretical position a non-zero angulation with the current position which can possibly mean the presence of a malfunction.

If the acceptable margin of error is respected, the avionics system of the helicopter therefore benefits from a safer measurement of the fuel level than that obtained by the prior art because it has not only been calculated but verified by an algorithm additional.

According to an alternative, if a difference between said current position and said theoretical position is not within a predetermined range of measurements, the method may comprise a step of issuing an alert.

The difference can be estimated in different ways, for example through an angle and / or a distance.

According to the example, if said inclination is not present in the stored range, an alert is generated.

Alternatively or additionally, if a difference between said current position and said theoretical position is not within a predetermined range of measurements, the method may include a step of searching for a malfunction for each capacitive sensor.

According to the example, if said inclination is not present in the stored range, a step of finding a malfunction is implemented for each sensor.

This step of searching for a malfunction can for example be undertaken if the gauging device comprises more than two capacitive sensors, or even more than three capacitive sensors. The step of searching for a malfunction of a capacitive sensor may comprise the following steps: measuring a piece of information relating to a height of liquid with each of the capacitive sensors that are not the subject of the verification step, estimating an alternative position of a surface plane of said liquid in the envelope by using said liquid heights measured with each of the capacitive sensors not being the subject of the verification step - if a difference between said position alternative and said theoretical position is not within said predetermined range of measurements, the capacitive sensor subject to the verification step is considered defective.

According to this variant, an additional step is implemented to estimate which capacitive sensor malfunctions. If the gauging device makes it possible to estimate the correct amount of fuel without using a particular capacitive sensor, the gauging device indicates that this capacitive sensor was at the origin of the problem encountered.

In addition, the measurements from the capacitive sensors can be used for example to estimate the attitude of a vehicle, and to determine if these estimates correlate with the avionics system of the vehicle. The invention and its advantages will appear in more detail in the following description with examples given by way of illustration with reference to the appended figures which represent: FIG. 1, a diagram showing a storage system, FIG. 2, a diagram showing a capacitive sensor arranged on an inner wall and a bottom, - Figure 3, a diagram illustrating various components of the gauging device, and - Figure 4, a diagram illustrating the process applied by the invention.

The elements present in several separate figures are assigned a single reference.

Three directions X, Y and Z orthogonal to each other are shown in some figures.

The first direction X is called longitudinal. The term "longitudinal" is relative to any direction parallel to the first direction X. A roll axis of the envelope shown may be parallel to this first direction X.

The second direction Y is called transverse. The term "transverse" is relative to any direction parallel to the second direction Y. A pitch axis of the envelope shown may be parallel to this second direction Y.

Finally, the third direction Z is said in elevation. The expression "in elevation" relates to any direction parallel to the third direction Z. A yaw axis of the envelope shown may be parallel to this third direction Z.

Figure 1 shows a storage system 10 according to the invention. This storage system 10 is intended to contain a liquid 14, such as fuel supplying a motor 5 for example. The storage system 10 may for example be arranged on a vehicle, and in particular on an aircraft 1. Such an aircraft 1 may in particular be a rotorcraft.

The storage system 10 is provided with a reservoir 11. This reservoir 11 can be arranged in a reservoir compartment 2 of a vehicle.

The reservoir 11 comprises an envelope 15 which delimits an internal space 12. For this purpose, the envelope 15 comprises multiple walls. For example, the envelope 15 is provided with a wall called "inner wall 16" which extends in elevation from a bottom 17 to an apex 18.

The inner wall 16 is laterally facing the internal space. This inner wall 16 may comprise several faces 161 to laterally delimit the internal space 12. Two adjacent faces 161 meet for example forming a corner 162 of the envelope 15. The inner space 12 is then delimited in elevation by the bottom 17 and the top 18. For example, the vertex 18 is substantially planar. The bottom 17 may have several inclined facets directed towards a low point of the envelope 15. Optionally, the storage system 10 comprises a fuel plate 20 at this low point. Such a fuel plate 20 may comprise, by way of example, a drainage tap, a purge valve, a pump 21, a pipe 22 directed towards a motor 5 .... From then on, a liquid 14 and a gas 13 can The interface surface between the gas 13 and the liquid 14 is referred to as the surface plane 100 for convenience. Such a gas 13 may be air, the envelope optionally comprising a conventional venting system.

In this context, the envelope 15 can be made of a rigid material, for example plastic. However, the envelope can be flexible by taking the form of a flexible seam. The envelope 15 can thus be folded to be introduced into the reservoir compartment 2, or to be extracted outside this reservoir compartment 2.

Furthermore, the storage system 10 comprises a gauging device 30 for estimating the quantity of the liquid 14 contained in the envelope 15. This quantity can be expressed in the form of a mass or a volume.

The gauging device 30 comprises at least two capacitive sensors 31, and for example two or at least three or at least four capacitive sensors 31. These capacitive sensors are flexible, unlike a gauging rod, and can therefore be optionally folded on themselves.

Each capacitive sensor 31 is further secured to at least the inner wall 16. For example, at least one capacitive sensor 31 or all the capacitive sensors 31 extend vertically along a corner 162 of the inner wall 16.

According to the first variant of FIG. 1, the capacitive sensors are only integral with the internal wall 16.

On the other hand, according to the second variant of FIG. 2, at least one of the capacitive sensors 31 or all the capacitive sensors is secured to the bottom 17 and to the inner wall 16. This arrangement can optimize the measurement when the surface plane is in a position 101 or when this surface plane touches the bottom, for example with a small amount of liquid and a roll angle or pitch Ω non-negligible.

Regardless of the variant and with reference to FIG. 1, at least one of the capacitive sensors 31 can be secured to the inner wall 16 or even to the bottom 17, being embedded in this inner wall 16 or even at the bottom 17.

According to another approach, the envelope 15 may be equipped with at least one fastening system 35 which is fixed to the inner wall 16 or to the bottom 17. A fastening system 35 keeps the capacitive sensor 31 against the inner wall or against the bottom in a predetermined position. An attachment system 35 may for example take the form of a link or a slide. As an illustration, an upper fastening system 36 and a lower fastening system 37 or even at least one intermediate fastening system 38 maintain in position a capacitive sensor 31 against the side wall.

In another aspect, the capacitive sensors 31 are distant from each other. Each capacitive sensor 31 then emits a signal 33 relating to the height of the liquid 14 in a predetermined detection zone of this capacitive sensor 31.

With reference to FIG. 3, the gauging device 30 comprises a computer 40 for processing these signals 33. For example, the computer 40 comprises a unit which is fixed to the fuel plate 20 and connected to each capacitive sensor by links 32 .

The computer 40 may comprise for example a processor, an integrated circuit, a programmable system, a logic circuit, these examples not limiting the scope given to the expression "calculator". As an illustration, the computer 40 may comprise at least one processor 42 communicating a memory unit 43. The memory unit 43 may comprise one or more memory strips for example.

In addition, the computer 40 may include input / output interfaces 41. For example, the input interfaces are connected to the capacitive sensors 31 to receive information relating to the height of the liquid at various measurement points, for example in the form of an electrical voltage.

Similarly, input interfaces may be connected to a first measurement unit 60 which measures at least one roll or pitch angle of the envelope. Such a first measurement unit 60 may take the form of an inertial unit, inclinometers ... The first measurement unit 60 then transmits to the computer information relating to a roll angle and / or a pitch angle of the 'envelope.

Input interfaces may be connected to a second measurement unit 70 which measures at least one acceleration of the envelope 15. Such a second measurement unit 70 may take the form of accelerometers ... The second measurement unit 70 for example, transmits to the computer information relating to an acceleration along a pitch axis of the envelope, and / or an acceleration along a rolling axis of the envelope, and / or an acceleration along a yaw axis of the envelope .

In addition, the gauging device 30 may comprise a display 50 and an alert system 80 integrated in the computer 40 or in communication with the computer via wired or wireless links and output interfaces.

A display 50 may for example include a screen displaying the amount of liquid. An alert system 80 can comprise a visual, audible or tactile alert means for generating an alert. Therefore, the computer injects in at least one mathematical model the information received, to deduce the amount of liquid or to generate an alert if a malfunction is detected.

Each mathematical model used can take various forms such as a database providing data as a function of input information, a mathematical law, a series of operations performed by the computer, etc.

In particular, the computer makes a first estimate of the quantity of liquid contained in the envelope as a function of the signals 33 emitted by the capacitive sensors 31. In addition, the computer verifies the first estimate using the roll angle and / or the measured pitch angel (s) as well as each measured acceleration, the calculator 40 generating an alert based on at least one predetermined criterion applied during said verification.

Figure 4 illustrates the process that can be applied.

During a first measurement step STP1, each capacitive sensor 31 measures information relating to a height of the liquid in a measurement zone of the associated internal space of the capacitive sensor.

During a step of estimating the amount of liquid STP2, the computer 40 determines a first estimate of the quantity of liquid using the information from the capacitive sensors 31 and a predetermined mathematical model.

For example, during a preliminary stage STP 2.1, the calculator 40 estimates the position of the surface plane 100, called "current position" for convenience. A first mathematical model taking into account the geometry of the envelope 15 makes it possible to determine this current position by means of at least two information of heights of the liquid given by the said at least two capacitive sensors 31.

During a step of calculating the first estimate STP 2.2, the calculator 40 calculates the first estimate by injecting the current position into a second predetermined mathematical model. The second mathematical model can be predetermined depending on the geometry of the envelope.

Optionally, the computer 40 can then implement verification steps to verify the first estimate.

During a second measurement step STP3, the first measurement means 60 estimates a roll angle and / or pitch of the envelope.

During a third measurement step STP4, the second measurement means 70 estimates at least one acceleration of the envelope.

During an intermediate step STP5, the calculator determines a theoretical position of the surface plane 100 by injecting into a third mathematical model the first estimate, the roll angle and / or the measured pitch angel (s), and each measured acceleration .

The third mathematical model can be predetermined depending on the geometry of the envelope.

During a consistency check step STP6, the computer determines whether a difference between the current position and the theoretical position is within a predetermined range of measurements.

If yes, no malfunction is detected and the amount of liquid can be displayed on the display during a first STP7 display step.

If not, a step of issuing an alert is implemented. For example, the computer communicates with the display to display the amount of liquid corresponding to the first estimate. Nevertheless, the computer communicates with the alert system to generate an alert.

Optionally and in particular in the presence of at least three or four capacitive sensors, during a step of searching for an STP8 malfunction, the computer tests the capacitive sensors one after the other.

For each capacitive sensor tested, the computer 40 requests a measurement of information relating to a height of liquid with each of the capacitive sensors 31 not being tested. Therefore, the calculator estimates an alternative position of the surface plane 100 in the envelope 15 using these heights.

If a difference between the alternating position and said theoretical position is not within said predetermined range of measurements, the capacitive sensor 31 being tested is considered defective.

Optionally and during a step of estimating a minimum quantity STP9, the computer 40 determines the quantity of liquid using the alternative position inducing the lowest amount of liquid.

This amount of liquid is then displayed on the display during a second STP10 display step, at the same time an alert is generated.

Naturally, the present invention is subject to many variations as to its implementation. Although several embodiments have been described, it is well understood that it is not conceivable to exhaustively identify all the possible modes. It is of course conceivable to replace a means described by equivalent means without departing from the scope of the present invention.

Claims (11)

A storage system (10) provided with an envelope (15) delimiting an internal space (12) for containing a liquid (14), said envelope (15) comprising an inner wall (16) facing said internal space ( 12), said storage system (10) having a gauging device (30) for estimating the quantity of liquid (14) contained in the envelope (15), characterized in that said gauging device (30) comprises at least two flexible capacitive sensors (31) each secured to said inner wall (16), each capacitive sensor (31) emitting a signal (33) representing a level of said liquid in a detection zone of this capacitive sensor (31), said capacitive sensors (31) being spaced apart from each other, said gauging device (30) comprising a calculator (40) connected to each capacitive sensor (31) for making a first estimate of said quantity as a function of said signals (33), said storage (10) a first measurement unit (60) for measuring at least one roll or pitch angle of the envelope, said storage system (10) having a second measurement unit (70) for measuring at least one acceleration of the envelope (15), said first measurement unit (60) and said second measurement unit (70) being connected to the computer (40), said computer (40) performing at least one verification of the first estimate using said at least one roll or pitch angle and said at least one acceleration, said calculator (40) being connected to an alert system (80) for generating an alert based on at least one predetermined criterion applied during said checking. 2. Storage system according to claim 1, characterized in that said gauging device (30) comprises at least three flexible capacitive sensors (31) each secured to said inner wall (16), said capacitive sensors (31) being remote from each other. each other. 3. Storage system according to any one of claims 1 to 2, characterized in that said envelope (15) is flexible, said envelope (15) being reversibly foldable by a cpérateur to be mounted in a reservoir compartment ( 2) or unfolded to be extracted from said reservoir compartment (2). 4. Storage system according to any one of claims 1 to 3, characterized in that said inner wall (16) comprising olusieurs faces (161), two adjacent faces (161) joining at a corner (162). ) of the envelope (15), at least one of said capacitive sensors (31) is arranged on a corner (162). 5. Storage system according to any one of claims 1 to 4, characterized in that said envelope (15) comprising a bottom (7) surmounted by said inner wall (16), at least one of said capacitive sensors (31) is secured to the bottom (17) and to said inner wall (16). 6. Storage system according to any one of the claims 1 to 5, characterized in that at least one of said capacitive sensors (31) 9st embedded in said internal wall (16). 7. Storage system according to any one of claims 1 to 5, characterized in that said casing (15) comprises at least one fastening system (35) for a capacitive sensor (31), this fastening system (35). now the capacitive sensor (31) associated against an inner wall (16) in a predetermined position. Aircraft (1) provided with a storage system (10), characterized in that said storage system (10) is according to any one of claims 1 to 7. 9. A method for measuring a quantity of liquid in a storage system (10), characterized in that the storage system (10) according to any one of claims 1 to 7, said method comprises the following steps: information relating to a liquid height with each of said capacitive sensors (31), each capacitive sensor (31) providing information relating to a height of the liquid in a measurement zone of said internal space (12), - determining a first estimation of the quantity of liquid using said information and a predetermined mathematical model, the step of determining said first estimate comprises the following steps: estimating a current position of a surface plane (100) in which is contained the surface of said liquid (14) in said envelope (15) using said measured heights and a predetermined mathematical model, o determining the said first estimate using said current position and a predetermined mathematical model, edit method comprising the following verification steps: - measuring at least one roll or pitch angle of the envelope - measuring at least one acceleration of the envelope (15), - determining a theoretical position of said surface plane (100) using said at least one measured roll or pitch angle as well as said at least one measured acceleration and said first estimate, - transmitting an alert if a difference between said current position and said theoretical position is not within a predetermined range of measurements. 10. Method according to claim 9, characterized in that, if a difference between said current position and said theoretical position is not included in a predetermined measurement range, the gauging device comprising at least three capacitive sensors said method comprises a step of searching for a malfunction for each capacitive sensor (31). 11. Method according to claim 10, characterized in that said step of seeking a malfunction of a capacitive sensor (31) comprises the following steps: measuring a piece of information relating to a height of liquid with each of the capacitive sensors (31) not subject to the verification step, - estimating an alternative position of a surface plane (100) of said liquid in the envelope (15) using said liquid heights measured with each capacitive sensors (31) not subject to the verification step, - if a difference between said alternating position and said theoretical position is within said predetermined range of measurements, the capacitive sensor (31) being subjected to of the verification step is considered defective.