WO2017093921A1 - Fuel tank with integrated level sensors, in particular for aircraft - Google Patents

Fuel tank with integrated level sensors, in particular for aircraft

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Publication number
WO2017093921A1
WO2017093921A1 PCT/IB2016/057241 IB2016057241W WO2017093921A1 WO 2017093921 A1 WO2017093921 A1 WO 2017093921A1 IB 2016057241 W IB2016057241 W IB 2016057241W WO 2017093921 A1 WO2017093921 A1 WO 2017093921A1
Authority
WO
Grant status
Application
Patent type
Prior art keywords
fuel
fuel tank
sensors
preceding
tank
Prior art date
Application number
PCT/IB2016/057241
Other languages
French (fr)
Portuguese (pt)
Inventor
FERREIRA Nelson Jadir MENDES
SILVA Joaquim Miguel FONSECA
SILVA FERNANDES Christophe DA
SANTOS DUARTE CARVALHO Pedro DOS
CARVALHO GOMES João Manuel DE
RIBEIRO Miguel Bruno VIEIRA
de Matos Bruno Guilherme Gonçalves
MONTES Ana Rita BENTO
PINTO André Lourenço CALDEIRA
da Costa Pereira Pedro Miguel Gonçalves
CORREIA ARAÚJO BARBOSA José Manuel GUSMAN
Original Assignee
Centitvc- Centro De Nanotecnologia E Materiais Técnicos, Funcionais E Inteligentes
Critical Materials, S.A.
Ceiia - Centro Para A Excelência E Inovação Na Indústria Automóvel
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B64AIRCRAFT; AVIATION; COSMONAUTICS
    • B64DEQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLYING SUITS; PARACHUTES; ARRANGEMENTS OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
    • B64D37/00Arrangements in connection with fuel supply for power plant
    • B64D37/02Tanks
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01FMEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00Indicating or measuring liquid level, or level of fluent solid material, e.g. indicating in terms of volume, indicating by means of an alarm
    • G01F23/22Indicating or measuring liquid level, or level of fluent solid material, e.g. indicating in terms of volume, indicating by means of an alarm by measurement of physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
    • G01F23/26Indicating or measuring liquid level, or level of fluent solid material, e.g. indicating in terms of volume, indicating by means of an alarm by measurement of physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields
    • G01F23/263Indicating or measuring liquid level, or level of fluent solid material, e.g. indicating in terms of volume, indicating by means of an alarm by measurement of physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields using capacitors
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60KARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS, IN VEHICLES
    • B60K15/00Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks
    • B60K15/03Fuel tanks
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60KARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS, IN VEHICLES
    • B60K15/00Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks
    • B60K15/03Fuel tanks
    • B60K2015/0321Fuel tanks characterised by special sensors, the mounting thereof
    • B60K2015/03217Fuel level sensors
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60KARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS, IN VEHICLES
    • B60K15/00Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks
    • B60K15/03Fuel tanks
    • B60K2015/0321Fuel tanks characterised by special sensors, the mounting thereof
    • B60K2015/03217Fuel level sensors
    • B60K2015/03223Fuel level sensors comprising at least two level fuel sensors
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60YINDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY
    • B60Y2200/00Type of vehicle
    • B60Y2200/50Aeroplanes, Helicopters
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60YINDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY
    • B60Y2200/00Type of vehicle
    • B60Y2200/50Aeroplanes, Helicopters
    • B60Y2200/51Aeroplanes

Abstract

A substantially polyhedral liquid fuel tank comprises: a plurality of capacitive sensors for detecting the level of liquid, arranged along an edge of the fuel tank such that the capacitance of said sensors varies with the volume of fuel inside the fuel tank, comprising in particular a plurality of electrically insulating plates arranged between each of the capacitive sensors and the fuel tank, the insulating plates being made of glass fibres and the capacitive sensors being embedded in the electrically insulating plates and being produced by screen-printing on PET. Also described is a method for determining the volume of fuel, comprising: taking the readings of the capacitive sensors for detecting the level of liquid, arranged along the edges of the fuel tank; calculating the volume, corresponding to the fuel volume, of the geometric solid defined by the fuel tank and by the top fuel surface as defined by the liquid level readings from the capacitive sensors arranged along the edges of the tank.

Description

DESCRIPTION

FUEL TANK WITH INTEGRATED LEVEL SENSORS,

IN PARTICULAR VEHICLE AIR

technical sector

[0001] The present disclosure relates to a fuel tank, in particular a fuel tank for aircraft, in particular of composite material using integrated or embedded sensing for reading the amount of fuel.

Background

[0002] The document US2015274005 discloses a fuel tank comprising: a fuel tank; a liquid level detecting sensor disposed in a vertical orientation within the fuel tank and configured such that a capacitance of the liquid level detection sensor varies according to a range in which fuel is in contact with the sensor detecting liquid level; a tubular member extending vertically and laterally around the liquid level detection sensor; a fuel storage member that communicates with the interior of the tubular member and the interior of the fuel tank through a fuel input / output port and configured to store the fuel inside the fuel tank.

[0003] The US2015274005 document is not suitable for use in vehicles, in particular aircraft because it can not measure the volume of fuel precisely when the tank is not perfectly horizontal, and does not take into account the possibility of the liquid to be fluctuate due to vehicle motion.

[0004] The GB752699A discloses a fuel tank with measuring the fluid contents of an irregular container through the use of a condenser, the fluid having as its dielectric, and having an electrode with a shape such that the surface level of electrode contact with the medium is proportional to the surface area of ​​the fluid at that level, and wherein a linear relation is obtained between the capacity and quantity of fluid. The measuring condenser comprises vertical and coaxial cylindrical members, being covered with a conductive material, but with openings to allow fluid to pass into the space between the member and the interior having a conductive layer shaped in a rigid insulating member. In its circuit, the voltage measured on the capacitor is compared with a reference, and any voltage unbalance is amplified and fed to a servomotor, balancing the reference and adjusting the voltage between the reference arms, as well as triggering an indicator that indicates the contents of the tank fluid.

[0005] The GB752699A document is not suitable for use in vehicles, in particular aircraft, because it measures the volume of fuel precisely when the tank is not perfectly horizontal, and does not take into account the possibility of the liquid is to swing due to vehicle movement.

[0006] These facts are described to illustrate the technical problem solved by embodiments of the present document.

General description

[0007] The present disclosure includes a fuel tank of an aircraft, made of composite material, using embedded or integrated reading of the amount of fuel sensing.

[0008] The present disclosure arises from the need for weight reduction, critical factor in aircraft structures and also the precise determination of the fuel level.

[0009] The present disclosure comprises the use of different configurations of sensors embedded in laminated composite materials with different compositions. Different sequences are possible lamination and orientation of composite fibers as well as various materials and variation in the order of stacking materials. In order to integrate sensors in composite carbon fiber components, such as an aeronautical tank, laminates are described comprising stacking layers of fiberglass embedded in epoxy. Considering the difficulty of integrating a sensor directly in composite carbon fiber was used, in one embodiment, glass fiber monolithic plate, enabling the production of plates of the sensor measurement to be installed without affecting the production of the constituent components of the tank structure of fuel.

[0010] Throughout the description and claims the word "comprise" and variations of the word, are not intend to exclude other technical characteristics, as other components, or steps. Additional objects, advantages and features of the disclosure will become apparent to those skilled in the art upon examination of the description or may be learned by practice of the disclosure. The following examples and figures are provided in order to illustrate, and not intended to be limiting of this disclosure. Furthermore, the present disclosure includes all possible combinations of particular and preferred forms of embodiment described herein.

Brief Description of the Figures

[0011] For easier understanding, join attached figures, which represent preferred embodiments that are not intended to limit the object of the present description.

Figure 1: Schematic representation of one embodiment of a schematic embodiment of an interdigitated sensor.

Figure 2: Schematic representation of one embodiment of the integrated sensor configuration layout, in particular plate or monolithic laminated glass fiber wherein 21 represents sensor (level, temperature, NFC TAG) 22 is PET substrate level sensor 23 is fiberglass laminate 24 is sensor cable (level, temperature) and component 25 is of carbon fiber composite.

REPLACEMENT (RULE 26) SHEET Figure 3A-B: Schematic representation of an embodiment of the geometrical arrangement of the sensors in the fuel tank.

Figure 4: Schematic representation of one embodiment of the tank with the identification number of the sensors.

Figure 5: Schematic representation of roll and pitch nomenclature.

Figure 6: Schematic representation of one embodiment of the composite test pieces with glass fiber (yellow center) on the composite surface with carbon fiber.

Figure 7: Schematic representation of an embodiment of interdigitated geometry of the sensor end.

Figure 8A-B: Schematic representation of one embodiment of a tag of the NFC integration scheme without ferrite shielding 51 which is NFC TAG sensor 52 is fiberglass and carbon fiber 53 is of composite structure.

Figure 9: Schematic representation of one embodiment of array of level sensors and temperature at which 91 represents sensor (level, temperature), 92 is PET substrate level sensor 93 is laminate glass fiber 94 is cable and sensor 95 is composite carbon fiber component. C = 1 mm (reference); D = 2 mm.

Figure 10: Schematic layout of an embodiment of the integration of the integrated sensor on the glass fiber.

Figure 11: Schematic representation of an embodiment of the integration of the layout NFC TAG

Figure 12: Schematic representation of one embodiment of data flow.

Figure 13: Schematic representation of an embodiment of the fuel tank when the dark spot is the geometry of the volume of fuel that is in the tank.

Figure 14: Schematic representation of an embodiment of the fuel mass filtering.

Figure 15: Schematic representation of the sensor capacity as installed on a fiberglass composite substrate, for different fuel levels with and without carbon fiber composite (driver) earthed.

SUBSTITUTE SHEET (RULE 26) Detailed Description

[0012] No one embodiment the interdigitated capacitive sensors are used because they have great sensitivity and allow, by varying their dimensions, adjust the measured capacitance values. Pa ra construction of the capacitive sensors can be printed using different techniques, the task having been used during the screen printing technique for printing conductive material of the electrodes, in this case silver, on the desired substrate. In one embodiment, the sensors were printed on the PET tests geometry definition.

[0013] No one embodiment, the construction of the sensor can follow the following steps:

1. Printing the electrode with screen printing equipment with silver ink on the PET substrate.

2. curing of the ink at a temperature of 130 ° C for 15 minutes.

3. Encapsulation of the sensor with another PET sheet with a thermal adhesive to glue the two PET sheets after rolling, being the protected sensor.

4. Trimming of the sensors according to the required size (0.2 to 2 mm margin).

5. Contacts are made for example crimping, and are themselves welded cables for handling higher temperatures. The cables are protected by shielding.

[0014] No one embodiment, the geometric distribution of the level sensors in the tank is one of the main factors that determine the accuracy of the measuring system of the quantity of fuel. In order to define a distribution printed level sensors inside the tank allowing the continuous sensing of the fuel level, for different attitudes of the aircraft, different approaches have been analyzed.

[0015] Considering a distribution system redundancy combining with the ability of measuring the fuel level for different attitudes, minimizing the number of required sensors has been developed a structure based on the principle of sensing the totality of the tank edges. This option is based on the consideration that the volume of any geometric solid can be estimated from the lengths of its edges. This length can be obtained starting from the output signal of each of the interdigitated sensors. Given the geometry selected, in one embodiment, sensorizar to all edges of the model considered deposit sixteen sensors are required to operate independently, as can be seen in the diagram shown in Figure 3 and Figure 4.

[0016] In one embodiment, the distribution considered for the sensors makes the system redundant when coupled with information from the aircraft attitude information can be obtained from separate instruments, thereby improving the robustness and accuracy of the measurements made. This distribution also has the advantage of, for example, to actions in which the pitch angle or roll the aircraft are zero, there are always fully submerged sensors, thus enabling the dielectric constant measuring the fuel to be used in system calibration. In other situations, it is not necessary that the pitch or roll angles of the aircraft are both zero, just that only one sensor is fully submerged to be able to assess the measurement. This measurement of the dielectric constant gives an indication of the type of fuel being used. In Figure 4, the numbering of the sensors is identified. The determination that the sensor is immersed can be made from the own capacitance data obtained by reading the sensor, eliminating the use of the aircraft attitude data.

[0017] In one embodiment, the compatibility of the various sensors and the structure of the deposit, particularly as regards structural ribs lead to the existence of maximum and minimum fuel volume above which the sensing is not possible. This limitation is inherent to the fuel tanks currently used, as under normal operating conditions these are always a residual fuel level that is not used or encoder unit.

[0018] In one embodiment, in order to use this array of sensors, it was necessary to find a volume calculation method which allows starting capacity obtained on each sensor, determining the volume of fuel for the different attitudes of the aircraft. The calculation of the irregular polygon volume can be calculated by decomposing the polygon pyramids that share a common point (located inside or on the surface of the polygon). Adding the volumes of these pyramids can calculate the original polygon volume. It is necessary to identify the coordinates of the vertices and identify the vertices present in every face.

[0019] No one embodiment, the outputs of each sensor can, according to the geometry and position of the sensor and of the tank geometry, be converted to the coordinates of the vertices formed by the liquid, thus allowing the calculation of its volume.

[0020] Assays were performed in interdigitated capacitive sensors printed by screen printing, the substrate used was polyethylene terephthalate (PET) and the same material being used as encapsulating the sensor.

[0021] Typically, an aircraft deposit consists of aluminum or composite material, both conductive properties. The influence of the conductive composite material, which would be connected to ground potential / mass of the aircraft required the integration of the sensor away from the carbon composite plate in an embodiment of the present disclosure. Accordingly placed in a glass fiber composite layer (electrically insulating and non-earthed / mass) with a well defined thickness.

[0022] No one embodiment, the carbon fiber composite material with glass fiber composite layer is shown in the previous figure. assays and as in this case were made the sensor would not be in contact with the carbon fiber composite, due to the existence of a layer of insulating material of considerable thickness between the two, it was expected that there would not be interference in the measurement of the capacity of sensor. The results are shown in Figure 15.

[0023] No one embodiment, the intermediate layer of glass fiber between the conductor composite and the sensor it possible to reduce the effect of the field produced by the conductive composite, and a reduction of about 16% which, although higher than the reduction caused by other solutions studied at the level of electronics, it is enough to operate the sensors. Furthermore the behavior remains linear, it is concluded that it is not necessary, applying the glass fiber layer, use more complex electronics.

[0024] In one embodiment, the sensors following the integration of fiberglass and subsequent bonding of this layer to the carbon fiber composite itself were coated with a coating material for fuel tanks for aircraft industry. Due to their oleophobic properties, thin layers ensures that fuel does not remain on the surface of the sensors. This coating has a contribution to the sensor capacity and later to its sensitivity. As the sensors have the same linear dependence on the fuel level, the straight calibration was calculated and considered in the construction of the final system.

[0025] In one embodiment, the altered sensor geometry considering the following parameters: width sensors, distance between teeth and long teeth. In one embodiment, the geometry showed adequate sensitivity, has a width of 20 mm and length of 17.2 mm teeth, tooth width 0.8 mm and 0.4 mm distance between teeth is shown in Figure 7.

[0026] An embodiment includes the use of printed tracks for the driving signal so as to reduce the weight of the structure by removal of signal conducting wires with respective complex and encapsulation and protection to radiation. The first difficulty was against the fact that the printed system signal driving as the tracks of level sensors, be susceptible to electromagnetic interference creating eddy currents. In fact, the protection of printed structures carbon composite signal for driving, require the use of additional layers of fiberglass, with a greater thickness, significantly increasing the weight of all the final composite structure. In this sense, for the correct operation of the entire system, and recalling that there are several level sensors in the use of print technology, for which the use of this type of composite structure, making use of carbon fiber, provides an aggravating weight and rising cost of integration, going against one of the main functional objectives, that is, weight reduction throughout the structure. Thus, the use of conventional wiring, the use of composite structures with carbon fiber resource, is preferred.

[0027] In one embodiment, due to the possible exposure of the whole system on current and potential constant parasites in the acquisition circuit was necessary to find a type of wiring comprising an effective electromagnetic shielding and which simultaneously supports the 200 ° C temperature whereby the material must pass during the autoclave process necessary for the composition of the composite structure. Following these purposes the material was identified polytetrafluoroethylene (PTFE), commercially known as Teflon ®, as a great high strength polymer ideal for the process of integration and also adaptable to the use of ranges in the usual composite structure.

[0028] In one embodiment, the cable type can have a coaxial presentation comprises four layers of material. Inside has a metallic material of high electric conduction, followed by a PTFE layer, a metal mesh immediately follows it too high electrical conductivity and finally PTFE material has a layer of greater thickness. Thus we have a high strength cable, being ideal for simultaneous use in highly complex systems and subjected to different electromagnetic environments.

[0029] In one embodiment, for each print level sensor, the use of two cables are required, one for each electrode, and the shielding mesh of the cable must have the same potential as the acquisition system and the entire structure of the deposit .

[0030] In one embodiment, chosen by the direct integration of a RTD (Resistance Temperature Detector), for example a commercial RTD (PT-100) bulk, such as SMD sensor (surface mount device) platinum supplied by Innovative sensor Technology - IST. The P0K1.0805.3PB reference sensor is small (2 x 1.2 x 0.4 mm) to minimize the impact of direct integration. This sensor meets specifications set operation, namely the temperature range from -40 ° C to + 55 ° C.

[0031] The integration into the composite structure is made by level sensors. In one embodiment, two RTD sensors should be positioned to acquire temperature, one is nearest the base of the tank and the other should be in a higher position. In order to facilitate the integration of commercial RTD, this was soldered to a printed circuit board (PCB) of small dimensions which are subsequently welded connection cables and sensor communication. It is subsequently fully integrated into the composite structure.

[0032] In one embodiment, the RTD sensor (PT-100) was incorporated into the composite structure with four wires. Its connection to the data acquisition system is performed with the use of four-wire, to ensure an acquisition of more accurate data, and a PCB aid, for a correct electrical connection of the sensor and the respective wires.

[0033] In one embodiment, an NFC device (or interchangeably, RFID) is integrated in the tank in order to be able to identify the deposit and receiving any information about this. After this NFC some existing devices on the market were purchased, for example, NFC devices Circus 25 mm in diameter and adhesive substrate which allows an easy implementation and integration into the composite structure and glass fiber composite. In one embodiment, since this device can not be stuck to a conductive surface, these were placed on a glass fiber layer can then be laminated to the tank.

[0034] Accordingly, NFC devices used TAG, identified and specified need not possess any kind of preparation for the integration to be as straight as possible in the composite structure with carbon fiber. Accordingly, in one embodiment, conditions were created for the NFC TAG devices work, creating a layer of material onto glass fiber, of carbon composite structure so as to create a sufficient distance to eliminate the natural interference with presence of a difference of potential parasite.

[0035] No one embodiment, a possible alternative to this system is the use of N FC TAG properly prepared to be coupled to conductive surfaces. Not only allow for a more esthetic solution, as the positioning device being on the outside of the tank, but also in that the glass fiber layer coming to increase the weight of the composite structure. O ne example of such systems are the TAG NFC devices with a shielding layer composed of ferrite between the antenna device and the adhesive layer. This allows use of N FC TAG device directly bonded in an electrically conductive surfaces, as is the case of the composite structure of carbon fiber. Thus eliminates the need to carry out an integration process with the aid of fiberglass, this process can be seen in Figure 8 (AB). In the case of using an N FC TAG device with shielding diminishes complex and iterative integration steps, also reducing the direct weight of the composite structure by reduced use of material, in particular glass fiber composite.

[0036] No one embodiment, the selected device can be for example NTAG213 29mm round of RapidN FC company with an adhesive layer enables a fast and immediate integration, and subsequently glued with a specific adhesive, in order to provide adequate physical protection, and the conductive outer surface of the tank.

[0037] No one embodiment, the plate of acquisition and transmission of data has developed different alternatives. The first was composed of an electronic circuit incorporating passive components such as resistors and capacitors, and active components (microcontroller PIC16LF1829) IC for capacity measurement (eg. AD7746), the IC for temperature measurement (ex.MAX31865) the voltage regulator (MIC5236), an operational amplifier and a transceiver for further communication via RS485 for example. [0038] In one embodiment, the microcontroller design used for the acquisition of this plate was PIC16LF1829 for example. This IC has the function to collect the data from the integrated measurement using e.g. via I2C communication to acquire the ability to respective values, and SPI communication via for example temperature values. Subsequent to this acquisition, this IC makes the processing of data and takes the slave position. In this regard, according to the commands coming from the master, the processed data is sent via an RS485 bus for example, using a transceiver to use to perform this transfer of information. In one embodiment, the capacitance measurement derived by level sensors, is carried an assembly which combines an operational amplifier and the IC AD7746.

[0039] In one embodiment, the IC AD7746 is a CDC ( "Capacitance-to-Digital-Converter") with the ability to make power measurements in the range 8 pF, or can measure and convert capabilities whose variation is ± 4 pF considering a reference to 17 pF. However, the derivative need for capacity measurement values ​​exceeding these was added an operational amplifier for example to increase the range of acceptable values ​​for the AD7746. In this sense, the junction of these two components can perform required measurements in the system to develop.

[0040] In one embodiment, for measuring the temperature, for example MAX31865 used for measuring the variation of resistance that results from PT100. This IC has the ability to convert this variation directly into a corresponding digital value at a temperature, thus eliminating the need to add extra circuitry.

[0041] The card power level so as to incorporate this circuit board by the end system in one embodiment was also a need to incorporate a regulator which converts the voltage normally used in aircraft systems (28 V) to the supply voltage used by all said components (3.3 V). [0042] In one embodiment allows the board with shielding cable connections to minimize outside interference, whether the reading of the sensors or communication.

[0043] In one embodiment, after assembly of all the plates, they were fixed inside boxes for example ABS (acrylonitrile butadiene styrene), and then proceeded to the integration of these acquisition modules. Finally there were two buses, a power (VDD and GND), and other communications for example RS485 (A and B) using flexible cables to facilitate positioning and gluing the modules in the tank.

[0044] Given all the electronic complexity associated with data acquisition modules, and respective operating close to threshold values ​​into the tank, it is easier to plan the placement of the modules on the outer faces. Therefore in one embodiment the data acquisition modules are protected from external environments using a plastic box formed with ABS polymer, coated with a layer of aluminum or copper sticker attached to the composite material to create a physical barrier to the elements external.

[0045] In one embodiment, in addition to the box, all of the hardware contained in ABS box is encapsulated by an epoxy resin, preferably Flame Retardant, to be placed during the process of integration of all hardware.

[0046] In one embodiment, the glass fiber laminate, connecting member between sensor and composite component of carbon fiber, used in level and temperature sensors, is an inorganic compound resistant to high voltages and moisture, since does not alter the physical and / or chemical properties, representing also a low dielectric constant electrical insulator with low thermal expansion coefficient.

[0047] In one embodiment, in order to allow the integration of different sensors have been used in composite components adhesives, especially adhesives in the form of liquid adhesive and film. In composite parts tested was used in a structural adhesive film and connections between component liquid adhesive was used. Due to the nature of the fuel applying treatment to the inner surfaces tank is required to safeguard the structural strength of the constituent components of the tank. Thus, in one embodiment, three types of surface treatments are considered, including priming, coating and sealing structure using an adhesive sealant.

[0048] The use of primary coating and relates to the need to protect the inner surfaces from the corrosive environment in which they operate. The sealing of the tank is essential to ensure functionality to the structure.

Table 1 - laminate configuration for integrated sensors.

Figure imgf000016_0001

[0049] In Table 1 is shown the laminate configuration used for the composite component of glass fiber.

[0050] The orientation of the glass fiber laminate comprises in one embodiment the alignment of the fibers to 0 ° with the longitudinal length (greater dimension) of the laminate of Figure 9 for the glass fiber level sensor, as detailed in the layout. To this glass fiber laminate temperature sensor in the direction of alignment of the fibers to be used is detailed in Figure 9.

[0051] In order to facilitate the integration of the various sensors in the composite structure components tank was determined integration of the temperature sensors and level in that it mined fiberglass, reducing thus possible failure causes during the process of production.

[0052] No one embodiment, concerning the carbon fiber components of the laminate configuration is not shown in view that this is dependent on the specifications of the tank structure. For example, considered a monolithic structure of several layers comprising different carbon fiber orientations for the integral components of the tank.

[0053] As described in the previous chapter, the production process comprises the manufacture of printed level sensors in the PET substrate, a first phase, as well as, simultaneously, the production process of composite components constituting the carbon fiber final structure. In secu NDA phase proceeds to the production of integrated sensors fiberglass specifically, level sensors and temperature sensors.

[0054] After production of all constituents proceeds to the assembly of the components, the method comprising integration of sensors integrated in the glass fiber constituent components of the tank. Due to the specific functionality of the sensors, the final stage of the production process comprises treating the internal surfaces where there is contact with the fluid, i.e. fuel. As described, the production process comprises four steps, however, will now be discussed the production of composite components, namely prepreg comprising carbon fibers and glass fibers, respectively, components of integrated structure and tank sensors. The constituent components of the tank structure are composed mainly of carbon fiber prepreg cured using the autoclave. [0055] The production of integrated sensors comprises fiberglass lamination using the autoclave adopting a procedure similar to component carbon fiber. Lamination and curing were performed with integrated sensors use of complex surface patterns in a "U".

[0056] The integration of various sensors in the respective laminates is guaranteed through the use of existing epoxy prepregs in, to temperature sensors and level. Regarding the NFC tag to unity is ensured through the use of existing adhesive on the sensor itself being provided for the use of additional adhesive, if necessary.

[0057] The integration of sensors comprises laminating the joint between the sensor (level and temperature) and fiberglass prepreg is proceeding with the subsequent bonding of the composite, as shown in Figure 10.

[0058] The integration with use of the adhesive between integrated sensor fiberglass and tank component is performed between the rough surface of the carbon fiber laminate and the surface of the integrated sensor die to ensure the adherence and between surfaces.

[0059] As detailed in the layout configuration of the integrated sensor wiring location comprises alignment with the purpose of fiberglass laminate part. Due to the various constituent layers of the coating cabling used, its stripping is preferred to avoid the weakening of the area and therefore the print grid connectors.

[0060] The procedure is applied to the level and temperature sensors. However, and considering the specificity of the NFC tag to application of diameter approximately 3mm sensor is directly made in the composite component tank carbon fiber. Therefore the application must be made in order to understand the present layout in Figure 11. [0061] The integration of the NFC TAG carbon fiber component is ensured through the adhesive present on the sensor itself, however, and if necessary, can be apply additional adhesive.

[0062] The lamination process comprises the following steps: cutting the prepegs, manual laminating of layers on the mold, compacting, curing procedure for preparing pre-test and tests for curing.

[0063] The application of various surface treatments comprises the constant monitoring of the working conditions, especially the temperature and humidity control. Thus all procedures to be applied to the components comprising the tank should preferably be effected between 13 ° C and 35 ° C and a relative humidity of 20% to 85%.

[0064] After several tests with different sensor configurations where surface treatments have been tried was determined using the specific configuration setting that is a fuel tank. Thus it was determined the need for protection of the constituent components of the tank with a primary coating and wherein the sensors are subject only to the coating application.

[0065] The application of coating on the surface of the integrated sensor comprises the following steps. 1. Surface preparation for application: cleaning using a clean cloth soaked in solvent. 2. Preparation of the component to be applied (coating). 3. Application of the mixture: stirring in order to ensure that no solidification in the container bottom; applied mixture preferably up to 24 hours after cleaning the surface prepared in the previous paragraphs; Application preferably 1 to 2 layers as needed in order to ensure a uniform and continuous application of the mixture. 4. Greetings of the mixture curing times. [0066] After application of the coating proceeds to the sealant application. The procedure is performed after curing assembly for the previous process.

[0067] The sealing comprises applying on the interface areas as well as the limits concerning the couplings parts / components. Thus the limit sensors integrated into the glass fiber component when integrated on the carbon fiber must be sealed to ensure a "cord" uniform and continuous seal. In order to ensure proper sealing of the component parts and equipment should be free of contaminants (eg. Dust) and component must be completely fixed to the end of the curing process.

[0068] After the application process or sealant or coating is required the visual inspection to ensure compliance with specifications.

[0069] Due to the use of different materials with different thermal expansion coefficients of the twist has been found and is considered a component of the compliance criteria, since excessive bending impair the bond between plates composite glass fiber and carbon fiber. The cable insulation shall comprise curing temperatures in order to avoid damage arising from handling or arising from elevated temperatures. After integration of sensors, movement of the ropes must be limited for example by the application of adhesive. The sensors should be visually inspected and tested in order to determine its correct functionality before applying the surface treatment procedure.

[0070] Given the aim of integrating sensors into composite fuel tanks, the developed integration process comprises the use of level and temperature sensors integrated into a plate glass fiber, subsequently integrated in the carbon fiber composite. The adoption of this method of integrating sensors into 2 phases comes from studies and experiments carried out in which the deformation was found in the carbon fiber composite when the sensors are integrated directly.

[0071] With the software developed is intended to acquire and convert the information from the sensors installed in the most appropriate engineering units. To this it was developed following a software architecture shown in Figure 12.

[0072] In the developed application data have come from the sensors, then moving by various processing modules, to be transformed into information in the most appropriate engineering units, and the results presented in the viewer (GUI).

[0073] The interdigitated capacitive sensors have the function of measuring the fuel level in various orientations / positions of the fuel tank. The measured values ​​allow, after processing, calculating the fuel volume.

[0074] The temperature sensors allow the acquisition of fuel temperature that is used for calculating the density and the total mass thereof. This information is important, given the volume and dielectric constant of the fuel itself vary with temperature.

[0075] In this model information from the sensors interdigitated percentage indicates the area covered by fuel sensor.

[0076] It is also in this module where the processing is carried out information from the sensors at points of interdigitated fuel surface coordinates, this being the input of the fuel level optimizer module. The sensor system model requires information of the position sensors in the fuel tank as well as the connection between sensors (eg. A vertex sensors or sensor extension).

[0077] In actual measurement systems are not usually obtained four or more points belonging to a same plane that is coplanar due to sloshing phenomenon and error in the measurements of the sensors. Hence it is necessary to adopt a strategy to get an estimated plan. The optimizer module fuel plan has as main function to process the four-coordinate or more points and generate an optimized plan that best represents the coordinates of the points. The cutting plane generated by this module is used by the tank model module for estimating the volume of liquid therein.

[0078] This module requires information about the geometry of the tank. The geometry of the tank is loaded from for example of a file in XML format containing information on the tank side. This module through the tank model and the resultant plan, generates a solid geometry of the tank filled with fuel and then calculated the volume. In Figure 13, the darker the solid is set equal to the corresponding part of the fuel.

[0079] After removal of all the geometric information of the fuel volume occupied is necessary to estimate its value, taking into account the sources of noise introduced in the whole process. The estimator module volume is converted to fuel mass; the fuel mass is estimated using data processing techniques and are detected and quantified fuel leakage.

[0080] The volume is converted to mass to obtain an invariant magnitude with temperature, used in the aeronautical sector fuel, as this is a more accurate measure of the volume. Usually to carry out this conversion density is necessary, given the fuel temperature at any given moment.

[0081] For data filtering were implemented two types of filters: the Kalman filter and the moving average filter.

[0082] The moving average filter is implemented with a weight for each sample. The number of samples is a filter configuration parameter. [0083] The Kalman filter was implemented using a dynamic first order system wherein the control variable (μ ^ is fuel flow and the state variable (¾) is the mass of fuel. The system output is zk, Wk and Vk are the measure of variance of the mass flow and mass measurement in the fuel.

[0084] Figure 14 is a graph of an exemplary curves of two filters as well as the mass prior to filtration.

[0085] Leakage is calculated based on the sum of the difference in fuel flow to the output time of the deposit by the difference in mass in an initial state and the current estimated weight by sensors installed in the fuel tank.

Leakage M = {ss IS - SS M ^) - (^ .at Flow)

[0086] In applying Kalman filter can improve monitoring of the fuel level when compared to the moving average method. However you need information on fuel consumption.

[0087] Although the present disclosure has just shown and described particular embodiments thereof, those skilled in the art will appreciate introduce modifications and substitute some technical features in other equivalents, depending on the requirements of each case, without departing from the scope of protection defined by appended claims.

[0088] The presented embodiments are combinable with each other. The following claims define further embodiments.

[0089] The term "comprises" or "comprising" as used herein indicates the presence of stated features, elements, integers, steps and mentioned components but does not preclude the presence or addition of one or more features, elements, integers, steps , components, or groups thereof.

[0090] The described embodiments are combinable with each other.

[0091] The present invention is of course not in any way restricted to the embodiments described herein and a person of ordinary skill in the area can provide many modification possibilities thereof and technical characteristics other equivalent substitutions, depending on the requirements of each situation as defined in the appended claims.

[0092] The following claims define further embodiments of the disclosure.

Claims

CLAIMS MULTIFUNCTIONDISPLAYS
substantially polyhedral liquid fuel tank comprising: a plurality of capacitive sensors liquid level detection, each disposed along an edge of the fuel tank so that the capacitance of said sensor varies with the present fuel volume fuel tank.
Fuel tank according to the preceding claim, wherein along each edge of the fuel tank is disposed a capacitive sensor liquid level detection.
Fuel tank according to any one of the preceding claims, wherein the capacitive sensor comprises interdigitated electrodes.
Fuel tank according to any one of the preceding claims, wherein the fuel tank is electrically conductive and comprises a plurality of electrically insulating plates arranged each between each of the capacitive sensors and the fuel tank, in particular with insulating plates all the same thickness and / or the insulating plates and glass fiber, more particularly capacitive sensors being embedded in the electrically insulating plates.
Fuel tank according to any one of the preceding claims, wherein the sensors comprise capacitive electrodes obtained by screen printing, in particular by screen printing on PET polyethylene terephthalate.
Fuel tank according to any one of the preceding claims, wherein the capacitive sensors are encapsulated by lamination between two sheets of PET, polyethylene terephthalate, in particular by thermal lamination.
Fuel tank according to any one of the preceding claims, comprising one or more temperatu r sensors to calibrate the mass measurement of this fuel in the fuel tank, which in particular additionally comprises an electrically insulating plate for supporting each temperature sensor the fuel tank, and more particularly insulating boards of glass fiber, more in particular the temperature sensors being embedded in the fiberglass plates.
Fuel tank according to claims 4 and 7 wherein each electrically insulating plate having a temperature sensor also has a capacitive sensor.
Fuel tank according to any one of the preceding claims, wherein the capacitive sensors are electrically connected by crimping and / or welding.
Fuel tank according to any one of the preceding claims, wherein each capacitive sensor comprising two interdigitated electrodes, in particular 10-30m m wide each comprising teeth having length of 7-27mm, of 0,5-2mm distance between teeth width and 0.2-lmm.
Fuel tank according to any one of the preceding claims, comprising shielded wiring to connect said capacitive sensors, in particular wiring coated polytetrafluoroethylene, PTFE.
Fuel tank according to any one of the preceding claims, comprising one or more N CF for individual identification and / or storage of individual fuel tank data devices, in particular further comprising an electrically insulating plate for supporting each NFC device in the tank fuel, more in particular with the insulating boards of glass fiber, more particularly NFC devices being embedded in the fiberglass plates.
13. Fuel tank according to any one of the preceding claims, further comprising a sealant layer as a liner to isolate the capacitive sensors within the tank.
14. Fuel tank according to any one of the preceding claims, wherein the capacitive sensors are further coated with an oleophobic layer for contact with the fuel tank.
15. Fuel tank according to any one of the preceding claims for vehicles, particularly for aircraft.
16. Fuel tank manufacturing method according to any one of the preceding claims, comprising:
have electrodes by screen printing on sheets of PET, polyethyleneterephthalate, for capacitive sensors;
encapsulating each capacitive sensor with other PET sheet;
connect electrical connections to the electrodes of said capacitive sensors;
optionally have one or more temperature sensors on PET sheet; laminating glass fiber sheets, each with a capacitive sensor and, if necessary, with a temperature sensor;
paste composite laminated sheet constituting the fuel tank;
applying the primary constituent of the composite fuel tank;
coating the surface of the composite component sensors glued to the fuel tank and cure;
apply sealant in the areas of interface, limits and unions of fuel tank components.
17. Method for the volume of fuel from a fuel tank according to any one of claims 1-15, comprising:
to obtain reading capacitive sensors of the liquid level detection arranged in the fuel tank edges;
calculating the volume corresponding to the fuel, the geometrical solid defined by the fuel tank and the upper surface of the fuel as defined by the liquid level readings of the capacitive sensors at the edges of the tank.
18. Method according to the preceding claim, wherein the calculation of the geometric solid volume comprises:
decompose in pyramidal volumes the volume of said corresponding geometric solid the fuel; and
add the volume of these pyramids.
19. Method according to any one of claims 17-18, comprising: if the capacitive fluid level sensor readings are divergent in the definition of the upper surface of the fuel, then
estimating the upper surface of the fuel through the calculation of the upper surface that minimizes the error in the divergent readings of the liquid level of capacitive sensors.
20. Method according to any one of claims 17-19, comprising: if it is determined, starting from the capacitive sensor readings from the fuel tank, at least one capacitive sensor is fully submerged, then calibrate sensors based on capacitive measurement capacitance sensor or capacitive sensors which are fully submerged.
21. Method according to any one of claims 17-20, comprising: obtaining additional data reading angles of inclination and bearing fuel tank; calculating the volume corresponding to the geometric solid fuel from the capacitive readings of the sensors and from the data of the angles of inclination and bearing fuel tank.
22. Method according to the preceding claim, comprising:
if it is determined, from the data of the angles of inclination and bearing fuel tank, at least one capacitive sensor is fully submerged, then calibrate the capacitive sensor based on capacitance extent or capacitive sensors that fully meet submerged.
23. A method according to claim 21 or 22, comprising:
if it is determined, starting from the readings of the capacitive sensors of the fuel tank or from the data of the angles of inclination and bearing fuel tank, at least one capacitive sensor is fully submerged, then measuring the dielectric constant the fuel in the fuel tank based on the measurement capacitance sensor or capacitive sensors which are fully submerged.
24. A method for determining the type of fuel from a fuel tank according to the preceding claim, comprising:
determine the type of fuel present in the fuel tank based on the dielectric constant measured.
25. A method for determining the amount of mass fuel from a fuel tank according to any one of claims 17-24, comprising:
estimating the density of fuel from one or more temperature sensors placed in the fuel tank;
calculate the mass of fuel present in the fuel tank from the volume corresponding to the estimated density of the fuel and the fuel.
26. A method for determining the amount of mass fuel from a fuel tank according to the preceding claim, comprising:
measure or calculate the mass of fuel injected into the deposit;
measuring or calculating the mass of fuel removed from the tank;
using an estimator filter to calculate the mass of fuel present in the fuel tank from the calculated mass of fuel present in the tank, the fuel mass injected into the deposit and withdrawal of the fuel mass storage.
27. Method according to the preceding claim wherein the estimator is a Kalman filter or a moving average filter.
28. A method according to claim 26 or 27, comprising calculating the amount of fuel mass lost by leakage from the estimated mass of fuel present in the tank, the fuel mass injected into the deposit and withdrawal fuel mass deposit.
29. Non-transitory storage medium comprising programming instructions to implement a fuel metering system of a fuel tank, wherein the programming instructions include instructions executable to perform the method of any one of claims 17-28.
30. electronic data processor comprising storage means according to the preceding claim.
31. Aircraft fuel system comprising the electronic data processor according to the preceding claim and fuel tank according to any one of claims 1-15, wherein the electronic data processor is connected to capacitive sensors tank fuel.
PCT/IB2016/057241 2015-12-01 2016-12-01 Fuel tank with integrated level sensors, in particular for aircraft WO2017093921A1 (en)

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PT10899915 2015-12-01

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Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB752699A (en) 1953-06-11 1956-07-11 Engineering Res Corp Ltd Capacitance-type fluid contents measuring apparatus
US3377861A (en) * 1965-05-06 1968-04-16 Simmonds Precision Products Electronic liquid measuring system
JP2005181165A (en) * 2003-12-22 2005-07-07 Alps Electric Co Ltd Liquid level sensor
DE102004051641A1 (en) * 2004-10-23 2006-04-27 Füner, Thorsten Measuring device for determining amount of fluid e.g. fuel in tank for portable gas cell system, has conductive strips connecting electrically flat capacitive sensors and/or flat conductive sensors
EP1722203A2 (en) * 2005-05-13 2006-11-15 Joma-Polytec Kunststofftechnik GmbH Measuring system for measuring the fill level of a liquid in a container
US20070157718A1 (en) * 2006-01-09 2007-07-12 U.S.A. As Represented By The Administrator Of The National Aeronautics And Space Administration System and method for wirelessly determining fluid volume
KR20120105982A (en) * 2011-03-17 2012-09-26 (주)하이텍알씨디코리아 Fuel sensor for model airplane
WO2013188443A2 (en) * 2012-06-12 2013-12-19 CAPLAN, Jeffrey, Brian Fluid level and volume measuring systems and methods of making and using the same
US20150274005A1 (en) 2012-11-20 2015-10-01 Toyota Jidosha Kabushiki Kaisha Fuel tank structure

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB752699A (en) 1953-06-11 1956-07-11 Engineering Res Corp Ltd Capacitance-type fluid contents measuring apparatus
US3377861A (en) * 1965-05-06 1968-04-16 Simmonds Precision Products Electronic liquid measuring system
JP2005181165A (en) * 2003-12-22 2005-07-07 Alps Electric Co Ltd Liquid level sensor
DE102004051641A1 (en) * 2004-10-23 2006-04-27 Füner, Thorsten Measuring device for determining amount of fluid e.g. fuel in tank for portable gas cell system, has conductive strips connecting electrically flat capacitive sensors and/or flat conductive sensors
EP1722203A2 (en) * 2005-05-13 2006-11-15 Joma-Polytec Kunststofftechnik GmbH Measuring system for measuring the fill level of a liquid in a container
US20070157718A1 (en) * 2006-01-09 2007-07-12 U.S.A. As Represented By The Administrator Of The National Aeronautics And Space Administration System and method for wirelessly determining fluid volume
KR20120105982A (en) * 2011-03-17 2012-09-26 (주)하이텍알씨디코리아 Fuel sensor for model airplane
WO2013188443A2 (en) * 2012-06-12 2013-12-19 CAPLAN, Jeffrey, Brian Fluid level and volume measuring systems and methods of making and using the same
US20150274005A1 (en) 2012-11-20 2015-10-01 Toyota Jidosha Kabushiki Kaisha Fuel tank structure

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