Method for estimating the vehicle-distributed load of a trailer coupled to the vehicle

Abstract

Disclosed is a method for estimating the variation in the load of a mounted assembly on a vehicle, the variation resulting from a trailer being coupled to the vehicle, the method comprising the following steps: ♦ coupling the trailer to the vehicle; ♦ recording the internal temperature T in the fluidic cavity of an equipped mounted assembly; ♦ ascertaining the internal pressure P in the fluidic cavity of the equipped mounted assembly using a specified law of change; ♦ evaluating a variation in the volume ΔV of the equipped mounted assembly by means of the recorded internal temperature T and the ascertained internal pressure P using a model of a fluid in adiabatic transformation, the fluid having a perfect gas behavior; and ♦ estimating a variation in the load ΔZ carried by the n equipped mounted assembly using a second function comprising, as a parameter, the evaluated intermediate variation in volume ΔV and the flattening stiffness of the tire of the mounted assembly per unit volume Kp.

Description

DESCRIPTION TITLE: METHOD FOR ESTIMATING THE LOAD DISTRIBUTED ON THE VEHICLE OF A TRAILER COUPLED TO THE VEHICLE Field of invention

[0001] The present invention relates to the field of real-time determination of the quasi-static load applied and in particular the load variation generated by the coupling of a trailer to a vehicle, in particular when the vehicle is stationary. Technological background

[0002] Obtaining the quasi-static load applied to a stationary vehicle makes it possible to determine whether the vehicle or each of the vehicle's axles is in a safe condition even before setting it in motion, which makes it more reliable and allows for compliance with safe traffic conditions. Indeed, determining the load applied to inflatable systems such as mounted assemblies generally requires a balancing scale; it is not easy to determine this load outside of very specific loading locations such as quarries where the trailer attached to the vehicle is loaded. In order to evaluate, outside of these specific locations, the load carried by the vehicle as well as by each axle of the vehicle, it is possible to evaluate the load carried by each mounted assembly of the vehicle through an indication of the tire's footprint on the ground.Although a measurement using a static pressure quantification system is possible by inserting the measurement system between the mounted assembly and the ground, its implementation is not simple and the accuracy of the measurement is subject to the correct positioning of the measurement system. Another alternative is to evaluate the dimension of the contact patch in rolling conditions by measuring the tire deformation at the wheel revolution in order to determine the dimension of the contact patch. Through a mathematical model, linking the type of tire, the inflation pressure and the external dimension of the footprint, we then go back to the load applied to the tire casing. Unfortunately, this measurement is in rolling conditions. As a result, the vehicle may no longer be within its safe operating range at the time of the measurement.Furthermore, the accuracy of these measurements is delicate for very heavy loads where the deformation of the tire which determines the load variations tends to stabilize according to the circumferential direction on which the evolution of the measurement of the deformation of the tire envelope generally relates.

[0003] The following objects and methods of the invention aim to solve the problem of measuring the load carried by the vehicle in the absence of a measuring system external to the vehicle, i.e. one that can be used at any time without specific measuring means. In addition, this evaluation is carried out while the vehicle is stationary, making it possible to decide on the safety criterion for loading the vehicle before any movement thereof. Description of the invention

[0004] The invention relates to a method for estimating the variation in load carried by a mounted assembly of a vehicle securely connected to a stationary trailer comprising the following steps: • In the preliminary phase, i.e. before coupling the trailer to the vehicle • Equip at least one mounted assembly of at least one axle of the vehicle not coupled to the trailer with at least one temperature sensor, said sensor being capable of measuring the internal temperature of the fluid cavity of the mounted assembly delimited by a pneumatic casing and a wheel, preferably at least one mounted assembly of each axle of the vehicle, very preferably all the mounted assemblies of all the axles of the vehicle; • Determine the initial load ZI applied to at least one mounted assembly equipped with the vehicle; • Determine the initial inflation pressure PI of at least one assembly fitted to the vehicle; • Determine the initial internal temperature Tl of at least one mounted assembly equipped with the vehicle; • Evaluate the initial volume VI of at least one mounted assembly equipped using a first function comprising as parameter the volume V0 of the fluid cavity of the mounted assembly unloaded and inflated to the initial pressure PI and the flattening rigidity of the tire of the mounted assembly per unit of volume Kp • Evaluate the number of moles of fluid n in the fluid cavity of each assembled assembly equipped from a model taking into account the inflation pressure PI, the initial volume VI, the temperature Tl; • Determine a law of evolution of the internal pressure P of the fluidic cavity from the internal temperature T during an adiabatic transformation for at least one assembled assembly, inflated and subjected to the load Zl, equipped with at least one pressure sensor; In the main phase, Attach the trailer to the vehicle at a geometry point M of the vehicle; • Record the internal temperature T of the fluidic cavity of at least one mounted assembly equipped at an acquisition frequency Fl; • Determine the internal pressure P of the fluid cavity of at least one equipped mounted assembly using the evolution law determined in the preliminary phase; • Evaluate an intermediate volume variation AV of at least one equipped assembly using the determined internal pressure P and the internal temperature T recorded using a fluid model in adiabatic transformation, the fluid having perfect gas behavior; and • Estimate a load variation AZ carried by each mounted assembly equipped using a second function including as parameter the intermediate volume variation AV evaluated, the flattening rigidity of the tire per unit of volume Kp.

[0005] According to a preferred embodiment, in the preliminary phase, the at least one mounted assembly equipped with the at least one axle of the trailer comprising a pressure sensor capable of measuring the internal pressure of the fluid cavity, the method comprises, in the main phase, a step for recording the internal pressure P of the fluid cavity of the at least one mounted assembly equipped when, at least the recorded internal temperature T changes direction of variation or after a duration T0 corresponding to the end of the adiabatic transformation of the fluid and the method comprises a second step of evaluating the intermediate volume variation AV2 of the at least one mounted assembly equipped taking into account the recorded internal pressure P, the recorded internal temperature T corresponds to the period of recording the internal pressure P using a fluid model in adiabatic transformation, the fluid having a perfect gas behavior.

[0006] The process of determining the variation of applied load comprises two successive phases. The first phase consists of identifying the intrinsic parameters of the assembled assembly before coupling the trailer to the vehicle. This constitutes an installation of the vehicle measurement system through the installation of measurement systems at the vehicle axles and the identification of the initial parameters of the mounted assemblies such as the volume of the fluid cavity, the quantity of fluid contained in the closed volume defined by the fluid cavity, the load initially applied to the mounted assembly by the uncoupled vehicle, the internal temperature of the fluid cavity and the inflation pressure of the fluid cavity of each mounted assembly. Intuitively, the nature of the fluid is assumed to be known to estimate the quantity of fluid trapped in the fluid cavity. It is also necessary to have a law of evolution of the variation of internal pressure P associated with the variation of internal temperature T of the mounted assembly when it is in use condition during an adiabatic transformation, in particular at the load ZI carried around the inflation pressure PI and the temperature Tl.This evolution law can be fixed or derived from an experimental characterization or a numerical simulation of the assembled assembly considered.

[0007] The second phase represents the step of evaluating the load variation applied to each mounted assembly equipped with an electronic device due to the coupling of the trailer to the vehicle. The electronic device including the temperature sensor manages and conditions the recording of the temperature measurement. Thus, recordings of the internal temperature of the fluid cavity of each mounted assembly equipped with an electronic device are made at the time of coupling the trailer to the vehicle. The temporal changes, in the transient phase, of the physical quantities of the fluid cavity are important. Coupling the trailer causes a first transformation corresponding to the work generated by this additional load which is similar to an adiabatic transformation, i.e. rapid and which is predominant compared to the second transformation.After the rapid transformation, a slower transformation follows, which corresponds to the thermal equilibrium of the fluid cavity with the external environment through the tire and the wheel. This equilibrium is necessary following the modification of the internal temperature of the fluid cavity associated with the work generated by the additional load. This thermal equilibrium is slower to be implemented due to the thermal inertia of the tire and the wheel. In addition, the thermal equilibrium is generally of smaller magnitude on the variation of volume of the fluid cavity than the transformation linked to the work. Preferably, the electronic device is fixed on the internal wall of the tire. The tire is in fact the most deformable element during the adiabatic transformation.Thus, the temperature sensor being further away from the wheel, the relative temperature variations compared to the absolute temperature measured are greater because the thermal inertia of the envelope is. less and that the wheel, especially the metal one, has by nature a greater inertia than that of the tire. As a result, this improves the accuracy of temperature measurement and therefore the quality of the load variation method.

[0008] Using the variation of the internal temperature of the fluid cavity, it is possible to determine the variation of the internal pressure of the fluid in the fluid cavity. For this purpose, the evolution law previously determined in the preliminary phase is used. It therefore converts the measurement of the internal temperature of the fluid in the fluid cavity and an evaluation of the internal pressure of the fluid generated by the adiabatic transformation alone.

[0009] Then, it is possible to evaluate a first intermediate volume variation using a fluid model undergoing an adiabatic transformation. Here, the term adiabatic means that the transformation that the fluid undergoes due to the coupling of the trailer to the vehicle is carried out without external heat exchange between the fluid cavity and the exterior of the mounted assembly, which assumes that it is rapid. Therefore, using only the variation of the measured internal temperature and the variation of internal pressure determined by the law of evolution from the variation of internal temperature of the fluid cavity, it is possible to estimate the first volume variation of the fluid cavity generated by the coupling of the trailer to the vehicle, the fluid having undergone an adiabatic transformation. We will make the entirely suitable assumption for air or nitrogen that the fluid, in the gaseous state, of the cavity of the equipped mounted assembly is an ideal gas.Of course, for this first evaluation of the volume variation corresponding to the adiabatic transformation of the fluid alone, it is appropriate to extract from the measured internal temperature variation only the changes associated with the adiabatic transformation. The end of the adiabatic transformation is characterized by a change in the internal temperature of the fluid cavity opposite to that of the adiabatic transformation. In addition, it is quite possible to estimate the duration T0 from which the adiabatic transformation of the fluid ends. Indeed, the event of coupling the loaded trailer to a vehicle is repeatable and reproducible, which makes it possible to set a duration T0 with precision and quality.

[0010] Preferably, a second intermediate volume variation is evaluated using a second transformation of the fluid. This second transformation is associated with the thermal equilibrium of the fluid with the exterior through the components of the mounted assembly. The second volume variation undergone by the mounted assembly following this second transformation is then evaluated using the variation in the internal temperature extracted from the initial recording of the internal temperature of the fluid cavity during the phase transient linked to the coupling of the trailer but subsequent to the first transformation of the fluid, that is to say when the temperature has reached the permanent regime or when the internal temperature of the fluid cavity changes evolution compared to the transformation linked to the work. In addition, the measurement of the internal pressure P(T) is used during this heat exchange to identify the second variation in volume. Taking into account this second variation in volume guarantees better precision in the evaluation of the variation in volume of the fluid cavity, which improves the precision of the measurement of the variation in load at the level of each equipped mounted assembly. However, the first intermediate variation in volume is sufficient for the estimation, to a first order of magnitude, of the overload applied to the mounted assembly.

[0011] It is necessary through the method, in preferential mode, to dissociate in the measurement of the internal temperature T of the fluidic cavity, the first transformation of the fluid, that qualified as adiabatic, from the second transformation of this same fluid which corresponds to the thermal equilibrium of the fluidic cavity with the external environment through the pneumatic envelope and the wheel. For this, the recording of the internal temperature of the fluidic cavity can indicate to us the passage from the first transformation to the second transformation by a change in the evolution of the internal temperature of the fluidic cavity. Indeed, the overload of a mounted assembly leads to a heating of the fluid of the fluidic cavity during the adiabatic transformation.Then, due to the thermal inertia of the pneumatic casing and the wheel, the thermal equilibrium of the second transformation of the fluid will tend to decrease the temperature reached at the end of the adiabatic transformation. Conversely, a discharge of the mounted assembly leads to the expansion of the fluid in the fluid cavity which cools during the adiabatic transformation. The thermal equilibrium which follows will lead to an increase in the temperature of the fluid in the fluid cavity by the external environment which is assumed to be at the initial temperature of the fluid before the discharge of the mounted assembly, therefore the external temperature is higher than the internal temperature at the end of the adiabatic transformation.

[0012] Of course, taking into account the variation in the external temperature of the mounted assembly resulting from the thermal equilibrium of the mounted assembly also makes it possible to refine the measurement of the second variation in volume, generated by the coupling of the trailer to the vehicle, at the level of each equipped mounted assembly. However, in a simplified approach, the mounted assembly being preferably in a thermomechanically stable state, it is possible to take as the external temperature the initial internal temperature Tl of the fluid of the fluid cavity of the mounted assembly.

[0013] These two fluid transformations can take place at each time increment or one after the other over a period of time measurements. These evaluations of the intermediate volume variation must be made with measurements during the transient period of loading of the vehicle until the establishment of mechanical and possibly thermal equilibrium of the mounted assemblies of the vehicle. Once these equilibria are established, the variations in temperature and therefore in pressure of the fluid cavity are infinitesimal, they are then in a new thermomechanically stable state.

[0014] Once the intermediate volume variation has been evaluated for the equipped mounted assembly, the associated static load variation resulting from coupling the trailer to the equipped mounted assembly of the vehicle must be evaluated. To do this, the intermediate volume variation of the equipped mounted assembly must be transformed into an equivalent load variation. To this end, a characteristic of the mounted assembly, in particular that of the tire, called flattening stiffness per unit volume Kp, must be taken into account. This quantity makes it possible to link the load carried by the mounted assembly to the volume variation of the fluid cavity generated by the load carried, the mounted assembly being crushed on a ground perpendicular to the applied load. This characteristic can of course be a fixed quantity or obtained by an experimental characterization of the mounted assembly or deduced from a numerical simulation campaign of the same mounted assembly.The assembled assembly must be in conditions of use close to those observed in the preliminary phase, that is to say around the internal temperature Tl and around the inflation pressure PI. Generally, this flattening rigidity of the assembled assembly is a quantity defined locally around the initial point of use of the assembled assembly in the reference frame associated with the internal pressure P, the internal temperature T and the volume of the fluid cavity V.

[0015] Preferably, before the main step, the at least one equipped mounted assembly is in a thermomechanically stabilized state.

[0016] It is preferable that the transient phenomena recorded at the level of the sensors of the electronic device are only due to the disturbance of the vehicle balance generated by the trailer coupling. Thus, the other disturbances do not influence the response of the sensors, which improves the accuracy of the load variation evaluated by the method. However, if the disturbance of the vehicle balance occurs on a different time scale than the disturbance associated with the trailer coupling or if this disturbance results in lower amplitudes of the responses of the sensors of the electronic device, the method remains entirely relevant.

[0017] Advantageously, the temperature sensor and the pressure sensor are placed in a subspace of the closed fluid cavity delimited by the pneumatic casing and the wheel.

[0018] It is advantageous for the sensors measuring low-amplitude transient phenomena to be placed close to the occurrence of these transient phenomena so as not to be drowned in the measurement noise. Thus, in the presence, for example, of a centralized inflation pressure system for the mounted assemblies, it is advantageous for the sensors to be located at the level of the mounted assembly and not at the level of the centralized system, generally far from the variation in volume of the mounted assembly. In the same logic, if the sensors are placed on the surface of the tire on the inside of the tire, the measurement will be more precise than if the sensors are mounted on the wheel rim due to the distance of the measurement from the occurrence of the physical phenomenon which acts on the deformation of the tire casing due to the transient nature of the physical phenomenon.Finally, preferably, the sensors, mainly due to the temperature sensor, are positioned far away from the wheel which has a higher thermal inertia than the tire.

[0019] Advantageously, the temperature sensor operates with a resolution of less than a hundredth of a degree.

[0020] Thus, it is possible to evaluate low volume variation and low load variation.

[0021] Advantageously, the acquisition frequency Fl is between 0.1 Hz and 10 Hz.

[0022] It is useful that the acquisition frequency Fl is high to capture the first transformation of the fluid which is rapid.

[0023] According to a particular embodiment, the determination of the initial volume V0 takes into account the geometry of a wheel rim and the geometry of an unloaded tire, mounted on a rim and inflated to a reference pressure PO, preferably the reference pressure PO is the initial pressure PI.

[0024] Advantageously, the geometry of the tire and / or the geometry of the rim is determined using an identifier of the tire and / or the wheel of the fitted assembly, preferably obtaining the identifier of said tire and / or said wheel is carried out by radiofrequency interrogation of an electronic device located on the fitted assembly.

[0025] To initiate the measurement system and in particular the determination of the initial volume VI of the fluid cavity, it is necessary to determine the volume V0 of the fluid cavity which corresponds to the volume delimited by the unloaded mounted assembly, i.e. the tire is mounted on the rim with a reference inflation pressure PO which is preferably the initial pressure PI.

[0026] To determine this volume V0, the axisymmetric geometry of the unloaded tire for a reference inflation pressure PO must be known. It is realistic to assume that the rim geometry is not influenced by the inflation pressure of the mounted assembly. These geometries can be accessed via a tire database. Knowing the identity of the tire and / or the wheel rim allows the correct geometries to be isolated in this database. The identity of the tire can be obtained through an optical reading of the regulatory markings affixed to the sidewall of the tire.The identity can also be transmitted by radio frequency interrogation of an electronic device present on the mounted assembly such as an RFID tag (acronym in English for Radio Frequency Identification), a TMS (acronym in English for "Tyre Mounted Sensor") mounted on the internal rubber of the tire or "inner liner" or a TPMS (acronym in English for "Tyre Pressure Monitoring System") mounted on the wheel rim for example.

[0027] Preferably, the Z load of each equipped mounted assembly is estimated by a Z = K PP * P * â(F) = Kpp * P * (Fl - F0) relation according to the following formula: [MATH1] ] , where Kpp is the flat-flat pneumatic stiffness of the assembled tire per unit volume.

[0028] This is a simple and elementary model that links the load Z applied to the tire to the variation in volume of the fluid cavity of the mounted assembly between a first state, for example unloaded, of volume V0 and a second state, for example loaded, of volume VI, the inflation pressure P of the fluid cavity and the pneumatic stiffness of the mounted assembly corresponding to the flattening of the mounted assembly on a plane. Through this model, we make the assumption that the structural stiffness of the mounted assembly is negligible compared to that of the pneumatic nature, which is a realistic assumption for a tire casing for a private vehicle. However, it is quite possible to take into account the structural stiffness of the tire in the previous formula by adding it to the product of the pneumatic stiffness by the inflation pressure.

[0029] According to an advantageous embodiment, the variation in volume AV of each equipped mounted assembly is estimated by solving a differential equation according to the form next: [MATH 2] and With [MATH 3] where P is the internal pressure, V is the internal volume and T is the internal temperature of the fluid cavity.

[0030] This differential equation translates the link between the parameters of the fluid in the cavity of the mounted assembly which are controlled on the one hand by an adiabatic transformation of the fluid and on the other hand by the fact that the fluid is a perfect gas.

[0031] The invention also relates to a method for estimating the load carried by a vehicle integrally connected to a trailer comprising the method for estimating the variation in the load carried by a mounted assembly of a vehicle generated by the coupling of a trailer when stationary, the method is characterized in that, in the preliminary phase, the method comprises a step of determining a first load distribution on each axle of the uncoupled vehicle, preferably on each mounted assembly of the vehicle, associated with the application of an additional load exerted at the coupling point M of the trailer on the uncoupled vehicle, optionally the method also comprises a step of determining a second load distribution on each axle of the uncoupled vehicle, preferably a second load distribution on each mounted assembly of the vehicle, associated with the weight of the uncoupled vehicle, in that, in the main phase,the method comprises a step of estimating the load Z carried by each mounted assembly of each axle i of the vehicle using the load variation AZ carried by the at least one equipped mounted assembly, the first load distribution associated with the application of an additional load to the coupling point M and the determination of the initial loads Zli of each mounted assembly of the uncoupled vehicle, optionally the step of estimating the load Z carried by each mounted assembly takes into account the second load distribution associated with the weight of the uncoupled vehicle, in that the method comprises a step of comparing to at least one threshold value S the load carried Z estimated at each axle i of the coupled vehicle and / or the total load carried of the, coupled vehicle which is the sum of the loads carried by each axle i of the vehicle, and when the at least one threshold value S is crossed, the mass content K of the trailer is adapted in the trailer during a secondary phase before carrying out again all the steps of the main phase.

[0032] By adding the load carried by the mounted assembly or the axle before the trailer is hitched, this makes it possible to evaluate the total load established at the level of the mounted assembly or axle i of the vehicle. The evaluation of the total load carried by the vehicle then comes down to simply adding the static loads established on all the axles i of the vehicle. It is then possible to verify that the loading conditions comply with the vehicle's safety instructions at the level of each mounted assembly, each axle of the vehicle and of course the vehicle before the vehicle even starts to roll.

[0033] By knowing the first load distribution at the level of the mounted assemblies or axles i of the vehicle associated with an overload applied to the coupling point M of the vehicle, it is possible to deduce from a single measurement on a mounted assembly equipped with the measuring device, the overloads on each mounted assembly or each axle of the vehicle linked to the trailer coupling. By adding this overload linked to the trailer coupling to the static load linked to the mass of the uncoupled vehicle seen from each mounted assembly, it is possible to estimate the total load applied to each mounted assembly or each axle i of the vehicle. Optionally, the static load linked to the mass of the uncoupled vehicle is obtained via the second load distribution on the mounted assemblies or axles i of the uncoupled vehicle associated with the mass of the uncoupled vehicle.

[0034] In the event that a safe driving condition is not obtained on the coupled vehicle, whether at the level of a mounted assembly, an axle or the complete vehicle. It is necessary to modify the arrangement of its contents, even if it means uncoupling the trailer from the vehicle, in order to shift the center of gravity of the trailer. This shift of the center of gravity of the trailer makes it possible to distribute differently on the vehicle the portion of the mass of the trailer taken up by the vehicle. Once the new arrangement has been made, it is necessary to repeat the process at the level of the main phase by coupling the trailer with its new arrangement and analyzing the load carried by each mounted assembly equipped with the vehicle. This new arrangement of the trailer can, for example, be a shift of the center of gravity of the contents of the trailer or a lightening of the contents of the trailer or the combination of the two.

[0035] The invention also relates to a system for implementing the method for estimating the variation in load carried by a mounted assembly of a vehicle securely connected to a trailer and / or the method for estimating the load carried by a vehicle securely connected to a trailer comprising: • a vehicle, fitted with a towing hook at a point M of the vehicle capable of receiving the attachment of a trailer, each axle i of which comprises at least one mounted assembly equipped with an electronic device; • the electronic device comprising at least one temperature sensor, at least one electronic chip, at least one memory space capable of recording the signals from the sensor, and at least one first means of radiofrequency communication at least in transmission, preferably, the electronic device is fixed on the internal wall of the tire, very preferably at the level of the crown of the tire; • At least one means of calculation; and • at least one display means comprising at least one second radiofrequency communication means at least in reception

[0036] As mentioned by the method, the temperature sensor should be located on the mounted assembly which is rotated relative to the vehicle. In order to move away from the elements of the mounted assembly with the highest thermal inertia, the electronic device is fixed to the inner wall of the tire at the level of the crown of the tire. Therefore, the electronic device conditioning at least the signals from the temperature sensor should be provided with a means of communication, for example radio frequency, in transmission to simply transmit the data beyond the mounted assembly where at least the display means will be located. Indeed, an alternative consists of integrating the calculation means, the one which calculates the variation in volume of the internal cavity of the mounted assembly at the level of the mounted assembly. This can be integrated into the electronic device or be in wired communication with the electronic device.So, the electronic device radio frequency communication means is useful for transmitting the results of calculations beyond the mounted assembly. The radio frequency communication from the electronic device of the mounted assembly can be to the vehicle or outside the vehicle to a device separate from the vehicle such as a mobile phone, a tablet, a computer. These three elements can then represent the display means. However, the display means can also be a graphical interface of the vehicle at the dashboard level for example.

[0037] Therefore, the proposed structural form allows it to adapt to several possible technical configurations while being functional for implementing the said process.

[0038] Preferably, the system comprises an analysis means capable of analyzing a result output from at least one calculation means.

[0039] The result of the calculation means is the variation in load carried by each mounted assembly equipped with the electronic device. If we want to obtain the total load and compare this quantity with a threshold S, an operation must be carried out before sending a message to the display means. This optional element of the system, which provides a service to the vehicle user, must be positioned between the calculation means and the display means. Structurally, it can be associated with one and / or the other by a wired connection or be physically dissociated from these elements by means of radiofrequency communication means.

[0040] According to a first particular embodiment, the at least one calculation means comprises at least one third radiofrequency transmission / reception communication means.

[0041] In the case where the calculation means is physically separated from the electronic device on the one hand and from the display means on the other hand, it is appropriate that the latter can communicate with the other two elements. This is the case, for example, when the calculation means is on the vehicle; it retrieves the pressure data from the electronic device via radio frequency communication with the latter. On the other hand, if the display means is on a mobile telephone, it transmits the calculation results to the display means via this radio frequency communication.

[0042] According to a second particular embodiment, the at least one analysis means comprises at least a fourth radiofrequency transmission / reception communication means.

[0043] In the case where the analysis means is physically separated from the calculation means and from the display means, it should be able to communicate with the other two elements. This is the case, for example, when the analysis means is on a server remote from the vehicle; it retrieves the loads applied to the various assemblies mounted on the vehicle. originating from the computing means present on the vehicle through radio frequency communication with the latter. On the other hand, if the display means is on a mobile phone, or any other electronic device equipped with a screen, it transmits the messages resulting from the comparison to the display means by radio frequency communication.

[0044] According to a third particular embodiment, the system comprises at least one reading means capable of at least reading data contained in the at least one memory space of the electronic device, comprising at least a fifth radiofrequency transmission / reception communication means.

[0045] In the case where the electronic device has a communication range that is not sufficient to ensure communication to the display means, it is appropriate to use a reading means to retrieve the data from the electronic device. This reading means ensures the function of capturing the measurement data. It then transfers them to the display means or any other element of the system requiring the data by radiofrequency communication for the rest of the process. This is a role of relaying the information by optimizing the communication coverage in relation to the electronic device present in the mounted assembly. Indeed, in order to reduce the mass of the electronic device at the tire level, it is appropriate to limit the energy source necessary for the transmission of data which is the energy-consuming function of the electronic device.

[0046] Preferably, part of the communication carried out by the communication means from and to the elements included in the group comprising the electronic device, the at least one calculation means, the at least one display means, the at least one analysis means and the at least one reading means is carried out by UHF radiofrequency waves, preferably in BLE (acronym in English for “Bluetooth Low Emission”).

[0047] The UHF band (acronym for Ultra High Frequencies) allows for significant data transmission with an interesting throughput, this is even more true in the high frequencies of the UHF band such as the BLE band (acronym in English for "Bluethooth Low Emission"). It is classically used in transport applications, which allows the system's communication means to be shared with those already present on the vehicle or in road infrastructures.

[0048] Advantageously, the at least one display means is included in the group comprising a telephone, a computer, a human-machine interface located on the vehicle, preferably located on the vehicle's instrument cluster.

[0049] The display means is used to warn the individual who is conducting operations on the vehicle of the safety of his convoy, whether he is the driver behind his driving position or another person responsible for the conformity of the convoy.

[0050] According to an advantageous embodiment, a part of the at least one reading means is located on the vehicle.

[0051] According to another advantageous embodiment, a part of the at least one calculation means and / or a part of the at least one analysis means is located on the vehicle, preferably located on the mounted assembly.

[0052] The vehicle is a natural information relay instrument since the mounted assembly is connected to it and the security condition is applied to it. Therefore, that the structural devices of the system are located on the vehicle is entirely desirable although the alternative is also possible. However, the vehicle allows to ensure a certain confidentiality of the data unlike communications to servers for example, unless secure communication protocols are implemented. Of course, in order to minimize the impact of this system in the vehicle environment which is today complex and loaded, the localization of the functions at the level of the mounted assembly makes it possible to limit interference with the other structural components of the vehicle. Brief description of the drawings

[0053] The invention will be better understood on reading the following description, given solely as a non-limiting example and made with reference to the appended figures in which the same reference numbers designate identical parts throughout and in which: • Fig. 1 presents a system for implementing the method for estimating the variation in load or the load carried by a mounted assembly of a vehicle securely connected to a trailer according to the first embodiment of the invention; • Fig. 2 shows another system configuration according to the second embodiment of the invention; • Fig. 3 presents a block diagram of the method for estimating the variation in load carried by a mounted assembly of a vehicle securely connected to a trailer and of the method for estimating the load carried by a mounted assembly of a vehicle securely connected to a trailer according to the invention; • Fig. 4 shows a temporal evolution of the internal temperature of the fluidic cavity at the outlet of the temperature sensor; • Fig. 5 shows a temporal evolution of the internal pressure of the fluid cavity at the outlet of the temperature sensor; • Fig. 6 presents a temporal estimate of the variation in volume of the fluidic cavity according to the invention; • Fig. 7 shows a time estimate of the load variation of a mounted assembly of the vehicle associated with the coupling of the trailer to the vehicle. Detailed description of the embodiments

[0054] Fig. 1 illustrates an example of a system 2000 enabling the implementation of the method for estimating the load carried by a mounted assembly of a vehicle securely connected to a trailer. This system 2000 comprises a vehicle 2001 comprising four mounted assemblies 2006 distributed over the two axles of the vehicle, the front axle and the rear axle following the direction of the vehicle 2001 in forward motion. The vehicle comprises a point M at the rear of the vehicle which allows the attachment of a trailer not shown in the figure. However, this trailer exerts an external force AZ on the vehicle 2001 at point M. The vehicle 2001 not coupled to the trailer comprises a center of gravity G where the weight P of the vehicle is applied which corresponds to the force generated by the total mass of the uncoupled vehicle taking into account the gravity of the Earth.This weight P is balanced by reaction forces exerted on the mounted assemblies 2006 of the vehicle which are called ZAV and ZAR depending on the axle where the mounted assembly 2006 is connected. The presence of an external force AZ on the point M of the vehicle, which corresponds to the ball joint of the trailer coupling of the vehicle 2001, causes the appearance of an additional reaction force AZAV and AZAR on the mounted assemblies 2006 of each respective axle which stabilize when the permanent regime is reached to balance the external force AZ.

[0055] The objective of the method is to determine the reaction forces on each mounted assembly of the vehicle which are stabilized when the steady state is reached.

[0056] At least one mounted assembly 2006 per axle of the vehicle 2001 is equipped with an electronic device 2007. This electronic device 2007 is located in the fluid cavity of the mounted assembly 2006. Here, the electronic device 2007 is placed on the inner wall of the tire in line with the tread of the tire casing which ensures contact between the ground and the tire casing. It would have been possible to install the electronic device at the wheel rim of the mounted assembly, while remaining in the fluid cavity of the mounted assembly 2006. For example, the electronic device could have been integrated into the rim valve like certain TPMS systems (Tyre Pressure Monitoring Systems).

[0057] This electronic device 2007 comprises a temperature sensor associated with a microcontroller and a radiofrequency device at least in transmission. The radiofrequency device therefore comprises a radio wave generator and a radiocommunication antenna for transmitting the generated radio waves. The radiofrequency device may also, optionally, comprise a radio wave receiver for receiving instructions from the outside in order, for example, to launch a measurement. This electronic device 2007 also comprises a memory space for storing the measurement data from the temperature sensor before transmitting them in the form of radio waves. The electronic device may transmit the raw measurement data or the data filtered by the microcontroller.Here, the electronic device 2007 emits radio waves in the UHF frequency band (acronym in English for Ultra High Frequency) and particularly in the BLE band (acronym in English for Bluetooth Low Emission).

[0058] Here, the exterior comprises at least the vehicle 2001. This vehicle 2001 firstly comprises a radio data reader 2005, operating in the UHF range, the antennas of which are located near the mounted assemblies 2006 in order to recover the measurement data generated by the electronic device 2007. The data are then transferred, here by wire, to the calculation means 2002 located in the vehicle 2001. A radio frequency transmission using specific means of communication would also have been possible.This calculation means 2002 includes memory space and a processor to carry out its tasks: identify the quantities of the assembled assembly corresponding to the initial state, solve the differential equation which leads to the determination of the variation in volume of the fluidic cavity of each assembled assembly equipped with an electronic device 2007, and finally calculate the variation in load associated with the variation in volume having previously recovered the quantities of the tires necessary for this final task.

[0059] The results, and in particular the last data, are sent to an analysis means 2004. Here, the transmission of this data is done by wire, but radio frequency communication could have been set up. The analysis means 2004 makes comparisons between the results of the calculation means 2002 and threshold values ​​previously entered. These threshold values, such as the maximum authorized load per axle of the vehicle or the maximum total load of the vehicle or the maximum authorized load per mounted assembly, are possibly transmitted by hard-entering this data into the vehicle 2001 or by querying a database remote from the vehicle 2001. Of course, the analysis means 2004 can be integrated into the calculation means 2002.

[0060] Finally, the various output data from this analysis means 2004 are transmitted to display means 2003 via a fourth communication means 2104 which is embodied, among other things, by the radiocommunication antenna of the vehicle 2001 and a second communication means 2102 present on the display means 2003.

[0061] These means of communication 2104 and 2102 transfer their data via a communication network to a tablet or smartphone 2003 in order to warn of the conformity or non-conformity of the vehicle's loading in relation to the threshold values ​​admissible by the vehicle 2001 according to the legislation in force.

[0062] In the event of non-compliance with the vehicle load, the trailer must be unhitched from the vehicle in order to modify the load, whether this involves reducing the mass of the load or changing the position of the load in the trailer in order to load the vehicle less when the trailer is hitched. The main phase of the process for estimating the load carried by a mounted assembly of a vehicle securely connected to a trailer must then be repeated in order to check the compliance of the vehicle loads with the legislation in force. If unhitching the trailer is preferred to modify the trailer load, this operation remains optional.It is perfectly possible to continue recording the measurement signals from the electronic device 2007 while the trailer load is being modified and then wait for the overall balance of the coupled vehicle 2001 to estimate the load carried by each mounted unit 2006 equipped with an electronic device 2007 of the vehicle 2001. Then compare these new loads with the threshold values ​​previously used in order to check the conformity of the vehicle 2001 with the legislation in force.

[0063] Fig. 2 shows another configuration of the system 2000. This system 2000 comprises a vehicle 2001 comprising four mounted assemblies 2006 distributed on the two axles of the vehicle, the front axle and the rear axle following the direction of the vehicle 2001 in forward motion. The vehicle includes a point M at the rear of the vehicle which allows the attachment of a trailer not shown in the figure. However, this trailer exerts an external force AZ on the vehicle 2001 at point M.

[0064] At least one mounted assembly 2006 per axle of the vehicle 2001 is equipped with an electronic device 2007. This electronic device 2007 is located in the fluid cavity of the mounted assembly 2006. Here, the electronic device 2007 is placed on the inner wall of the tire in line with the tread of the tire casing which ensures contact between the ground and the tire casing. It would have been possible to install the electronic device at the wheel rim of the mounted assembly, while remaining in the fluid cavity of the mounted assembly 2006. For example, the electronic device could have been integrated into the rim valve like certain TPMS systems (Tyre Pressure Monitoring Systems).

[0065] This electronic device 2007 comprises a temperature sensor associated with a microcontroller and a radiofrequency device at least in transmission. The radiofrequency device therefore comprises a radio wave generator and a radiocommunication antenna for transmitting the generated radio waves. The radiofrequency device can also, optionally, comprise a radio wave receiver for receiving instructors from the outside in order, for example, to launch a measurement. This electronic device 2007 also comprises a memory space for storing the measurement data from the temperature sensor before transmitting them in the form of radio waves. The electronic device can transmit the raw measurement data or the data filtered by the microcontroller.Here, the electronic device 2007 emits radio waves in the UHF frequency band (acronym in English for Ultra High Frequency) and particularly in the BLE band (acronym in English for Bluetooth Low Emission).

[0066] Here, the exterior comprises at least the vehicle 2001. This vehicle 2001 firstly comprises a radio data reader 2005, operating in the UHF range, whose reception antennas 2105 are located near the mounted assemblies 2006 in order to recover the measurement data generated by the electronic device 2007. The data are then transferred, here by wire, to the transmission antenna of the communication means 2105 associated with the data reader 2005 located in the vehicle 2001. A radio frequency transmission using specific communication means would also have been possible between the transmission communication means 2105 and the data reader 2005.

[0067] The data is then transmitted to physical means remote from the vehicle 2001.

[0068] The first means is a calculation means 2002 comprising transmission / reception communication means 2102. These communication means 2102 receive the radio waves emitted by the transmission communication means 2105 to transform them into digital data usable by the calculation means 2002. The calculation means 2002 comprises memory space and a processor to carry out its tasks: identify the quantities of the mounted assembly corresponding to the initial state, solve the differential equation which leads to the determination of the variation in volume of the fluid cavity of each mounted assembly equipped with an electronic device 2007, and finally calculate the variation in load associated with the variation in volume having previously recovered the quantities of the tires necessary for this final task.

[0069] The results and in particular the last data are sent to a second means which corresponds to an analysis means 2004. Here, the transmission of these data is done by means of a radio frequency communication. The analysis means 2004 makes comparisons between the results of the calculation means 2002 which they recover by radio frequency transmission from the calculation means 2002 using reception communication means 2104 and the threshold values ​​previously entered. These threshold values ​​such as the maximum authorized load per axle of the vehicle or the maximum total load of the vehicle or the maximum authorized load per mounted assembly are possibly transmitted by querying a remote database containing data on the vehicle 2001. Of course, according to another embodiment, the analysis means 2004 can be integrated into the calculation means 2002.

[0070] Finally, the various output data from this analysis means 2004 are transmitted to display means 2003 via a fourth communication means 2104 in transmission and a second communication means 2102 present on the display means 2003. Here, the display means are twofold. Firstly, a digital tablet 2003 possibly remote from the vehicle 2001 and a man-machine interface 2003 within the vehicle 2001 comprising a display screen on the dashboard of the vehicle 2001.

[0071] The 2003 display means aim to warn of the conformity or non-conformity of the vehicle loading in relation to the threshold values ​​admissible by the 2001 vehicle according to the legislation in force.

[0072] Of course, these two embodiments of the system for implementing the method for estimating the load carried by a mounted assembly of a vehicle securely connected to a trailer are only illustrative examples of the system which are not limited to these two configurations. A first extreme configuration consists of integrating all of the calculation and analysis means within the electronic device on board the mounted assembly which transmits the results to a display means remote from the vehicle. The other extreme configuration consists of transferring by radio waves the measurement data recorded at the electronic device and carrying out the other steps of the method on means remote from the vehicle, without ever passing through the vehicle.

[0073] Fig. 3 shows a block diagram of the process for estimating the load variation and / or the load carried by a mounted assembly equipped with a vehicle securely connected to a stationary trailer. This process comprises several phases.

[0074] The first is a preliminary phase which includes at least actions 1 to 6 which follow one another through a continuous line link system. This preliminary phase which focuses on the vehicle not coupled to the trailer obviously includes the equipment of the vehicle, ideally at the level of the mounted assemblies, by the installation of a temperature sensor capable of measuring the internal temperature of the fluid cavity delimited by the internal surface of the tire and the wheel rim by means of a dedicated electronic device. The first steps, noted 1 and 2, consist of determining the physical quantities of the fluid cavity of the mounted assemblies equipped with the measuring device such as the inflation pressure PI and the internal temperature TL Preferably, these determinations can be made as a lump sum or through a specific measurement.Step 3 consists of determining the load carried ZI by the assembled assembly equipped with the measuring device of the uncoupled vehicle. This determination can be made on a flat-rate basis by making assumptions about the distribution of the total load of the vehicle between the various axles of the vehicle. The total load of the vehicle being a given, for example from the manufacturer, corresponds for example to the unladen mass of the vehicle as specified by the technical instructions of the vehicle manufacturer. Of course, it is also possible to include a full tank of fuel, luggage in the trunk of the vehicle. Step 4 corresponds to obtaining specific quantities of the assembled assembly equipped with a measuring device.One of these quantities is the volume V0 which corresponds to the volume occupied by the fluid cavity of the assembled assembly when the assembled assembly is inflated to pressure PI, strictly speaking, under the internal temperature Tl, but in the absence of any load carried, i.e. not resting on the ground. The second quantity is the rigidity of. flattening of the pneumatic envelope of the mounted assembly per unit of volume Kp, possibly depending on the inflation pressure PI, the internal temperature Tl and the load carried Zl. Finally, a third set of quantities are those associated with the ideal gas behavior laws for the nature of the gas contained in the fluidic cavity of the mounted assembly. And the penultimate step of the preliminary phase, referenced 5, is a step of determining the volume occupied VI by the fluidic cavity of the instrumented mounted assembly subjected to the load Zl and under the inflation pressure PI and the temperature Tl. Finally, the last step, noted 6, of the preliminary phase is the evaluation of the quantity of gas contained in the fluidic cavity of the instrumented mounted assembly by determining the number of moles of gas n present within the volume VI.Here, the assumptions associated with the ideal gas condition apply well, it is still necessary to identify the nature of the composition of the gas, i.e. a monatomic gas or a gas mixture. In addition, it is important in this preliminary phase, although not shown, to determine the evolution law linking the variation of internal pressure P to the variation of internal temperature T for the fluid of the fluidic cavity of the mounted assembly considered during an adiabatic transformation around the operating point of the mounted assembly, i.e. the pressure PI, the temperature Tl and the load Zl. Finally, in the preliminary phase, it is necessary, although not shown, to determine the load distribution on each axle of the vehicle, preferably on each mounted assembly of the vehicle, associated with a load applied to the coupling point M of the vehicle.Optionally, a second load distribution on each axle of the vehicle, preferably on each mounted assembly of the vehicle, the vehicle being uncoupled, can be considered. This second load distribution is linked to the total mass of the uncoupled vehicle.

[0075] Then we move on to the main step, the beginning of which corresponds to the coupling of the trailer to said vehicle. Necessarily, we record the temporal variation of the temperature T(t) of each instrumented mounted assembly of the vehicle, which are of the order of a hundredth of a degree for passenger vehicles and trailers adapted to this type of vehicle. These recordings are then stored in a memory space to first filter the raw data using a low-pass filter to eliminate high-frequency phenomena, which corresponds to step referenced 11. Then we determine the temporal variation of internal pressure P(t) of the fluid cavity using the temporal variation of internal temperature T(t) by using the evolution law determined in the preliminary step, which corresponds to step 12. Optionally, we record the temporal variation of the internal pressure P(t) of each instrumented mounted assembly of the vehicle, if it is equipped with a pressure sensor, which corresponds to step 12. In this option, the internal pressure variation P(t) is used to evaluate the second transformation of the fluid corresponding to the thermal equilibrium of the fluid of the fluidic cavity of the equipped mounted assembly and the environment external to the mounted assembly which is made necessary by the transformation linked to the work of the fluid associated with the coupling of the trailer to the vehicle. The connection system between optional steps and the steps essential to the process are illustrated with gray colored lines instead of being black. But, the connection systems of the main phase are illustrated by dotted lines, while those of the preliminary phase are solid lines. Finally, as will be seen later, the secondary phase has a connection system in the form of dashed lines.

[0076] One of the important steps of the main phase is the determination of the volume variation AV of the fluid cavity of each instrumented mounted assembly through step 13. This corresponds to taking into account at least the transformation linked to the work of the fluid of the fluid cavity due to the instantaneous attachment of the trailer to the vehicle which modifies the thermomechanical equilibrium of all the mounted assemblies of the vehicle and consequently of the fluid trapped in each fluid cavity of the mounted assemblies. In addition, the fluid is assumed to follow the behavior of an ideal gas. From the internal temperature variation T(t) of each instrumented mounted assembly, it is possible to determine the internal pressure variation P(t) through the devolution law identified in the preliminary phase for an adiabatic transformation of the fluid.

[0077] Using the variation of the internal pressure and the internal temperature, it is possible to feed a differential equation taking into account the previous hypotheses. The resolution by time increment of the differential equation makes it possible to obtain an estimate of the associated time variation of the volume of the fluidic cavity AV(t). Optionally, the method can be completed by the measurement of the variation of the internal pressure P of the fluidic cavity in order to evaluate a second variation of volume of the fluidic cavity associated with the transformation corresponding to the thermal equilibrium of the fluid with the external environment due to the heat exchange which is established between the fluidic cavity of the mounted assembly and the external environment through the components of the mounted assembly; that is to say the pneumatic casing and the wheel.This second transformation is generally subsequent to the transformation linked to work since it is the variation in temperature. generated by the adiabatic transformation which is at the origin of the thermal imbalance between the fluidic cavity and the external environment.

[0078] Another important step in the main phase is the evaluation of the load variation AZ associated with the single volume variation previously evaluated AV which corresponds to step 14. For this, it is necessary to take into account again the flattening rigidity of the assembled assembly Kp per unit of volume. This rigidity can include a pneumatic component and a structural component. Taking into account a single pneumatic component Kpp can be sufficient for a reliable estimation of the load variation AZ.

[0079] From this variation in load carried AZ, the initial load carried ZI must be added to obtain the load carried by the instrumented mounted assembly in step 15. From this quantity on the scale of the mounted assembly, it is easy to return to the load carried by axle load i of the vehicle and therefore to the total load carried by the vehicle. For this, assuming that only one or a few mounted assemblies, but not all of the vehicle, are equipped with a measuring device, the method comprises in a preliminary phase an estimation of the load distribution on each mounted assembly or each axle of the vehicle associated with an overload applied to the coupling point M of the uncoupled vehicle. Optionally, a second load distribution can be used to estimate the initial load of each mounted assembly or each axle of the uncoupled vehicle associated with the mass of the uncoupled vehicle alone.

[0080] The last step, noted 16, is the comparison of the load carried Z with respect to a threshold S at the level of each mounted assembly, but also in the same way for each axle i of the vehicle and finally at the level of the complete vehicle. Generally, these thresholds S can be the safety conditions specific to each national legislation for the circulation of the vehicle.

[0081] According to the result of this comparison, the vehicle is fit to take the road with the trailer coupled to the vehicle since all the safety conditions are respected according to step 17 of the main phase. Otherwise, a secondary phase is followed comprising at least step 20 in which the loading of the coupled trailer is adapted. This adaptation of the loading can take place while the trailer remains coupled. It may also be considered to uncouple the trailer from the vehicle during this adaptation of the trailer loading. The adaptation of the loading consists of a modification of the location of the load in the trailer and / or a modification of the contents of the load in order, for example, to reduce the mass of the load. Once step 20 is completed, it is appropriate to repeat the main step, if necessary reattaching the trailer to the vehicle and recording the internal temperature of each instrumented assembly of the vehicle, which corresponds to step 11 of the synopsis. This secondary phase is repeated until the criteria authorizing the execution of step 17 are met.

[0082] Fig. 4 shows the time evolution of the temperature delivered by the temperature sensor of the electronic device placed on a mounted assembly of the vehicle. The curve consisting of points 10 is the raw measurement of the temperature sensor while curve 11 corresponds to the time evolution of the filtered internal temperature, which is cleaned of high-frequency noise. It is this second curve which will then be used in the synoptic of figure 3.

[0083] This time recording of the internal temperature of the fluid cavity of the mounted assembly begins in the preliminary phase before the trailer is hitched to the vehicle. The moment of hitching of the trailer corresponds to the abscissa of point 100 which marks the beginning of the main phase. From this point 100, a rapid drop in the internal temperature of the fluid cavity is observed until point 101 where the drop in temperature stops and even increases to a lesser extent. This point 101 marks the transition between the work of the fluid associated with the hitching of the trailer which corresponds to a first transformation of the fluid which is similar to a transformation linked to the work generated by the applied overload then the heat exchange towards the outside which corresponds to a second transformation of the fluid. The abscissa of this point 101 corresponds to the duration T0 taking as the origin of the times the abscissa of point 100.Thus, the preliminary phase 50 ends at the abscissa of point 100. It precedes the main phase which is separated into two successive phases. The first phase 51 is similar to an adiabatic transformation of the fluid corresponding to the work of the fluid following the coupling of the trailer. The second phase 52 corresponds to a thermal exchange of the fluid with the exterior.

[0084] Fig. 5 shows the time evolution of the internal pressure of the fluid cavity. Here, this time evolution is either delivered by a pressure sensor of the electronic device arranged on a mounted assembly of the vehicle as illustrated by curve 12.

[0085] This evolution of the internal pressure 12 of the fluid cavity of the mounted assembly begins in the preliminary phase before the trailer is coupled to the vehicle. The moment of coupling of the trailer corresponds to the abscissa of point 100 which marks the beginning of the main phase. From this point 100, we then observe a rapid drop in the internal pressure of the fluid cavity up to point 101 where the drop in pressure stops and then increases to a certain extent. This point 101 marks the transition between the work of the fluid associated with the coupling of the trailer which corresponds to a first transformation of the fluid which is similar to an adiabatic transformation and the heat exchange towards the outside which corresponds to a second transformation of the fluid. The abscissa of this point 101 corresponds to the duration T0 taking as the origin of the times the abscissa of the point 100. Thus, the preliminary phase 50 ends at the abscissa of the point 100. It precedes the main phase which is separated into two successive phases. The first phase 51 is similar to an adiabatic transformation of the fluid corresponding to the work of the fluid following the coupling of the trailer. The second phase 52 corresponds to a heat exchange of the fluid with the outside.

[0086] Fig. 6 shows the time evolution of the internal volume of the fluid cavity. Here, this time evolution, represented by the curve, is the output of the calculation of the volume variation by the proposed differential equation, also taking into account the thermal equilibrium with the external environment.

[0087] This evolution of the internal volume of the fluid cavity of the mounted assembly begins in the preliminary phase before the trailer is hitched to the vehicle. The moment of hitching of the trailer corresponds to the abscissa of point 100 which marks the beginning of the main phase. From this point 100, we then observe a rapid increase in the internal volume of the fluid cavity up to point 101 where the increase in the internal volume stops and then decreases to a certain extent. This point 101 marks the transition between the work of the fluid associated with the hitching of the trailer which corresponds to a first transformation of the fluid which is similar to an adiabatic transformation then the heat exchange towards the outside which corresponds to a second transformation of the fluid. The abscissa of this point 101 corresponds to the duration T0 taking as the origin of the times the abscissa of point 100. Thus, the preliminary phase 50 ends at the abscissa of point 100.It precedes the main phase which is separated into two successive phases. The first phase 51 is similar to an adiabatic transformation of the fluid corresponding to the work of the fluid following the coupling of the trailer. The second phase 52 corresponds to a thermal exchange of the fluid with the exterior.

[0088] It is noted that at the end of phase 51, a good estimate of the variation in volume of the mounted assembly is obtained, which clearly shows that the work generated by the variation in load subjected to the mounted assembly occurs mainly during phase 51. The variations or oscillations observed correspond to the fluctuations of the transient phase corresponding to thermal equilibrium. Therefore, the method described here produces a continuous measurement of the variation in the internal volume of the mounted assembly in the time domain.

[0089] Fig. 7 shows the time evolution of the load variation applied to a mounted assembly equipped with the electronic device. Here, this time evolution, represented by curve 14, is the output of the calculation of the volume variation by the proposed differential equation taking into account the thermal equilibrium with the external environment which is multiplied by the flattening rigidity of the mounted assembly. Here, the rigidity taken is that which is locally identified at the level of the initial pressure of the mounted assembly, of the initial load applied to the mounted assembly and corresponding to the initial temperature. We could have taken into account the global rigidity defined by the proposed formula which would already have given a good order of magnitude.

[0090] This evolution of the charge 14 of the fluid cavity of the mounted assembly begins in the preliminary phase before the trailer is coupled to the towing vehicle. The moment of coupling of the trailer corresponds to the abscissa of point 100 which marks the beginning of the main phase. From this point 100, a rapid decrease in the charge is observed, corresponding to a discharge in this case, up to point 101 where the drop in the load stops and then decreases to a certain extent. This point 101 marks the transition between the work of the fluid associated with the coupling of the trailer, which corresponds to a first transformation of the fluid similar to an adiabatic transformation, and the heat exchange towards the outside, which corresponds to a second transformation of the fluid. The abscissa of this point 101 corresponds to the duration T0 taking as the origin of the times the abscissa of point 100. Thus, the preliminary phase 50 ends at the abscissa of point 100.It precedes the main phase which is separated into two successive phases. The first phase 51 is similar to an adiabatic transformation of the fluid corresponding to the work of the fluid following the coupling of the trailer. The second phase 52 corresponds to a thermal exchange of the fluid with the exterior.

[0091] It is noted that at the end of phase 51, a good estimate of the load variation applied to the mounted assembly is obtained, which clearly shows that the work generated by the load variation occurs mainly during phase 51. The variations or oscillations observed correspond to the fluctuations of the transient phase corresponding to the thermal equilibrium. Therefore, the method described here produces a continuous measurement of the temporal load variation of the mounted assembly in the time domain. Curve 80 corresponds to the measurement on a ground scale of the overload applied to the mounted assembly of the trailer, which guarantees a reasonable estimate of the overload applied to the equipped mounted assembly. In conclusion, the applied load variation is well captured by the proposed method.

Claims

CLAIMS 1. Method for estimating the variation in load carried by a mounted assembly of a vehicle generated by the coupling of a trailer when stationary, comprising the following steps: In the preliminary phase, - Equip at least one mounted assembly of at least one axle of the vehicle not coupled to the trailer with at least one temperature sensor, said sensor being capable of measuring the internal temperature of the fluid cavity of the mounted assembly delimited by a pneumatic casing and a wheel, preferably at least one mounted assembly of each axle of the vehicle, very preferably all the mounted assemblies of all the axles of the vehicle; - Determine the initial load ZI applied to at least one mounted assembly equipped with the uncoupled vehicle, - Determine the initial inflation pressure PI of the fluid cavity of at least one mounted assembly equipped with the vehicle; - Determine the initial internal temperature Tl of the fluid cavity of at least one mounted assembly equipped with the vehicle; - Evaluate the initial volume VI of at least one equipped mounted assembly using a first function comprising as parameter the volume VO of the fluid cavity of the unloaded mounted assembly inflated to the initial pressure PI and the flattening rigidity of the tire of the mounted assembly per unit of volume Kp, - Evaluate the number of moles of fluid n in the fluid cavity of each assembled assembly equipped from a model taking into account the inflation pressure PI, the initial volume VI, the temperature Tl; - Determine a law of evolution of the internal pressure P of the fluidic cavity from the internal temperature T during an adiabatic transformation for the at least one assembled assembly, inflated and subjected to the load Zl, equipped with at least one temperature sensor; In the main phase: - Attach the trailer to the vehicle at a geometry point M of the vehicle - Record the internal temperature T in the fluid cavity of at least one mounted assembly equipped at an acquisition frequency Fl; - Determine the internal pressure P of the fluid cavity of at least one equipped mounted assembly using the evolution law determined in the preliminary phase; - Evaluate an intermediate volume variation AV of at least one equipped assembly using the determined internal pressure P and the internal temperature T recorded using a fluid model in adiabatic transformation, the fluid having a perfect gas behavior; and - Estimate a load variation AZ carried by the at least one mounted assembly equipped using a second function comprising as parameter the intermediate AV volume variation evaluated and the flattening rigidity of the tire of the mounted assembly per unit of volume Kp.

2. Method for estimating the variation in the load carried by a mounted assembly of a vehicle generated by the coupling of a trailer when stationary according to claim 1 in which, in the preliminary phase, the at least one mounted assembly equipped with the at least one axle of the trailer comprising a pressure sensor capable of measuring the internal pressure of the fluid cavity, the method comprises, in the main phase, a step for recording the internal pressure P of the fluid cavity of the at least one mounted assembly equipped when, at least the recorded internal temperature T changes direction of variation or after a duration TO corresponding to the end of the adiabatic transformation of the fluid and the method comprises a second step of evaluating the intermediate volume variation AV2 of the at least one mounted assembly equipped taking into account the recorded internal pressure P,the recorded internal temperature T corresponds to the recording period of the internal pressure P using a fluid model in adiabatic transformation, the fluid having an ideal gas behavior., 3. Method for estimating the load carried by a mounted assembly of a vehicle generated by the coupling of a trailer when stationary according to one of claims 1 to 2 in which, before the main step, the at least one equipped mounted assembly is in a thermomechanically stabilized state.

4. Method for estimating the variation in the load carried by a mounted assembly of a vehicle generated by the coupling of a trailer when stationary according to one of claims 1 to 3 in which the temperature sensor and / or the pressure sensor are placed in a sub-space of the closed fluid cavity delimited by the pneumatic casing and the wheel.

5. Method for estimating the variation in the load carried by a mounted assembly of a vehicle generated by the coupling of a trailer when stationary according to one of claims 1 to 4 in which the acquisition frequency Fl is between 0.1 Hz and 10 Hz.

6. Method for estimating the variation in the load carried by a mounted assembly of a vehicle generated by the coupling of a trailer when stationary according to one of claims 1 to 5 in which the determination of the initial volume V0 takes into account the geometry of a wheel rim and the geometry of an unloaded tire, mounted on a rim and inflated to a reference pressure PO, preferably the reference pressure PO is the initial pressure PI.

7. Method for estimating the variation in the load carried by a mounted assembly of a vehicle generated by the coupling of a trailer when stationary according to claim 6 in which the geometry of the tire and / or the geometry of the rim is determined using an identifier of the tire and / or the wheel of the equipped mounted assembly, preferably obtaining the identifier of said tire and / or said wheel is carried out by a radiofrequency interrogation of an electronic device located on the mounted assembly.

8. Method for estimating the variation in the load carried by a mounted assembly of a vehicle generated by the coupling of a trailer when stationary according to one of claims 1 to 7 in which the load Z of each equipped mounted assembly is estimated by a relationship according to the following formula: [MATH1] Z = K p * P * A(F) = K P * P * (Fl - FO) Where Kpp is the flat tire stiffness of the assembled tire per unit volume.

9. Method for estimating the load carried by a mounted assembly of a vehicle securely connected to a trailer according to one of claims 1 to 8 in which the variation in volume AV of each equipped mounted assembly is estimated by solving the following differential equation: [MATH 2] With [MATH 3] where P is the internal pressure, V is the internal volume and T is the internal temperature of the fluid cavity.

10. Method for estimating the load carried by a vehicle integrally connected to a trailer comprising the method for estimating the variation in the load carried by a mounted assembly of a vehicle generated by the coupling of a trailer when stationary according to one of claims 1 to 9, the method is characterized in that, in the preliminary phase, the method comprises a step of determining a first load distribution on each axle of the uncoupled vehicle, preferably on each mounted assembly of the vehicle, associated with the application of an additional load exerted at the coupling point M of the trailer on the uncoupled vehicle, optionally the method also comprises a step of determining a second load distribution on each axle of the uncoupled vehicle, preferably a second load distribution on each mounted assembly of the vehicle, associated with the weight of the uncoupled vehicle, in that, in the main phase,the method comprises a step of estimating the load Z carried by each mounted assembly of each axle i of the vehicle using the load variation AZ carried by the at least one equipped mounted assembly, the first load distribution associated with the application of an additional load to the coupling point M and the determination of the initial loads Zli of each mounted assembly of the uncoupled vehicle, optionally the step of estimating the load Z carried by each mounted assembly takes into account the second load distribution associated with the weight of the uncoupled vehicle, in that the method comprises a step of comparing to at least one threshold value S the load carried Z estimated at each axle i of the coupled vehicle and / or the total load carried by the coupled vehicle which is the summation of the loads carried by each axle i of the vehicle, and when the at least one threshold value S is crossed,the mass content K of the trailer is adapted in the trailer during a secondary phase before carrying out all the steps of the main phase again., 11. System (2000) for implementing the method (1000) for estimating the variation in load carried by a mounted assembly of a vehicle securely connected to a trailer according to one of claims 1 to 9 and / or the method for estimating the load carried by a vehicle securely connected to a trailer according to claim 10 comprising: - a vehicle (2001), provided with a towing hook at a point M of the vehicle capable of receiving the attachment of a trailer, each axle i of which comprises at least one mounted assembly (2006) equipped with an electronic device (2007); the electronic device (2007) comprising at least one temperature sensor, at least one electronic chip, at least one memory space capable of recording the signals from the sensor, and at least one first radiofrequency communication means (2101) at least in transmission; at least one calculation means (2002); and at least one display means (2003) comprising at least one second radiofrequency communication means (2102) at least in reception 12. System (2000) for implementing the method for estimating the variation in load and / or the load carried by a mounted assembly of a vehicle securely connected to a trailer according to claim 11 in which the system (2000) comprises an analysis means (2004) capable of analyzing a result output from the at least one calculation means (2002).

13. System (2000) for implementing the method (1000) for estimating the variation in load and / or the load carried by a mounted assembly of a vehicle securely connected to a trailer according to one of claims 11 to 12 in which the at least one calculation means (2002) comprises at least one third radiofrequency transmission / reception communication means (2103).

14. System (2000) for implementing the method (1000) for estimating the variation in load and / or the load carried by a mounted assembly of a vehicle securely connected to a trailer according to claim 13 in which the at least one analysis means (2004) comprising at least a fourth radiofrequency transmission / reception communication means (2104) 15. System (2000) for implementing the method (1000) for estimating the variation in load and / or the load carried by a mounted assembly of a vehicle securely connected to a trailer according to one of claims 11 to 14 in which the system (2000) comprises at least one reading means (2005) capable of at least reading data contained in the at least one memory space of the electronic device (2007) comprising at least one fifth communication means (2105) at least in reception.

16. System (2000) for implementing the method (1000) for estimating the variation in load and / or the load carried by a mounted assembly of a vehicle securely connected to a trailer according to one of claims 11 to 15 in which part of the communication carried out by the communication means (2101, 2102, 2103, 2104, 2105) from and to the elements included in the group comprising the electronic device (2007), the at least one calculation means (2002), the at least one display means (2003), the at least one analysis means (2004) and the at least one reading means (2005) is carried out by UHF radiofrequency waves, preferably in BLE.

17. System (2000) for implementing the method (1000) for estimating the variation in load and / or the load carried by a mounted assembly of a vehicle securely connected to a trailer according to one of claims 11 to 16 in which the at least one display means (2003) is included in the group comprising a telephone, a computer, a human-machine interface located on the vehicle (2001), preferably located on the instrument cluster of the vehicle (2001).

18. System (2000) for implementing the method (1000) for estimating the variation in load and / or the load carried by a mounted assembly of a vehicle securely connected to a trailer according to one of claims 11 to 17 in which a part of the at least one reading means (2005) is located on the vehicle (2001).

19. System (2000) for implementing the method (1000) for estimating the variation in load and / or the load carried by a mounted assembly of a vehicle securely connected to a trailer according to one of claims 11 to 18 in which a part of the at least one calculation means (2002) and / or a part of the at least one analysis means (2004) is located on the vehicle (2001), preferably located on the mounted assembly (2006).

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