EP-4735275-A1 - METHOD FOR ESTIMATING THE VARIATION IN THE VOLUME OF AN INFLATABLE SYSTEM SUBJECTED TO AN EXTERNAL FORCE

EP4735275A1EP 4735275 A1EP4735275 A1EP 4735275A1EP-4735275-A1

Abstract

Disclosed is a method for estimating the variation in the volume ΔV of an inflatable system, the variation resulting from an external force being applied to the stationary inflatable system, the method comprising the following steps: applying the external force F to the deformable surface of the inflatable system; recording the internal temperature T in the fluidic cavity of the equipped inflatable system at an acquisition frequency F1; recording the internal pressure P in the fluidic cavity of the equipped inflatable system at a frequency F2; and evaluating a variation in the volume ΔV of the equipped inflatable system by means of the recorded internal temperature T and the recorded internal pressure P using a model of a fluid in adiabatic transformation, the fluid having a perfect gas behavior.

Inventors

QUADRINI, MATTHIEU
PERNOT, Alexandre
MARTIN, DENIS
BERLIOUX, LOIC

Assignees

COMPAGNIE GENERALE DES ETABLISSEMENTS MICHELIN

Dates

Publication Date: 20260506
Application Date: 20240625

Claims (14)

1. Method for estimating the variation in AV volume of an inflatable system generated by the application of an external force to the stationary inflatable system comprising the following steps: In the preliminary phase, - Equip the inflatable system with at least one temperature sensor, said sensor being capable of measuring the internal temperature of the fluid cavity of the inflation system delimited by at least one deformable surface of the inflatable system; - Equip the inflatable system with at least one pressure sensor, said sensor being capable of measuring the internal pressure of the fluid cavity of the inflation system; - Determine the initial load ZI exerted on the deformable surface of the inflatable system; - Determine the initial inflation pressure PI of the fluid cavity of the inflatable system; - Determine the initial internal temperature Tl of the fluid cavity of the inflatable system; - Evaluate the initial volume VI of the fluid cavity of the inflatable system using a first function comprising as parameter the volume VO of the fluid cavity of the unloaded inflatable system inflated to the initial pressure PI and the rigidity of the deformable surface of the inflatable system per unit volume Kp, - Evaluate the number of moles of fluid n in the fluid cavity of the inflatable system equipped from a model taking into account the inflation pressure PI, the initial volume VI, the temperature Tl; In the main phase: - Apply the external force on the deformable surface of the inflatable system; - Record the internal temperature T of the fluid cavity of the equipped inflatable system at an acquisition frequency Fl; - Record the internal pressure P of the fluid cavity of the equipped inflatable system at a frequency F2; and - Evaluate a variation in AV volume of the equipped inflatable system using the internal temperature T recorded and the internal pressure P recorded using a fluid model in adiabatic transformation, the fluid having ideal gas behavior.
2. Method for estimating the volume variation AV of an inflatable system generated by the application of an external force to the inflatable system when stationary according to claim 1, in which, in the preliminary phase, the method comprises a step of determining a law of evolution of the internal pressure P of the fluid cavity from the internal temperature T during an adiabatic transformation of the fluid of the fluid cavity of the inflatable system inflated and subjected to the load Zl, in the main phase, the method comprises a step of extracting the internal temperature variations T' generated by the sole adiabatic transformation of the fluid from the recording of the internal temperature T, the method comprises a step of determining an internal pressure P' of the fluid cavity of the inflatable system from the internal temperature T' and the law of evolution determined in the preliminary phase and the step of evaluating the volume variation AV of the inflatable system comprises a first phase where the evaluation is carried out with the extracted internal pressure P' and the determined internal temperature T' and at least one second phase where the evaluation is carried out with a part of the internal pressure P recorded outside a time frame corresponding to the extracted internal pressure variations P’ and a part of the recorded internal temperature T outside said time frame.
3. Method for estimating the volume variation AV of an inflatable system generated by the application of an external force to the inflatable system when stationary according to claim 1, in which, in the preliminary phase, the method comprises a step of determining a law of evolution of the internal temperature T of the fluid cavity from the internal pressure P during an adiabatic transformation of the fluid of the fluid cavity of the inflatable system inflated and subjected to the load Zl, in the main phase, the method comprises a step of extracting the internal pressure variations P' generated by the sole adiabatic transformation of the fluid from the recording of the internal pressure P, the method comprises a step of determining an internal temperature T' of the fluid cavity of the inflatable system from the internal pressure P' and the law of evolution determined in the preliminary phase and the step of evaluating the volume variation AV of the inflatable system comprises a first phase where the evaluation is carried out with the extracted internal temperature T' and the determined internal pressure P' and at least one second phase where the evaluation is carried out with part of the internal temperature T recorded outside a time frame of the extracted internal temperature variations T' and part of the recorded internal pressure P outside said time frame.
4. Method for estimating the variation in volume AV of an inflatable system generated by the application of an external force on the inflatable system when stationary according to claim 2, in which the extraction of the variation in internal temperature T' ends when 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.
5. Method for estimating the variation in volume AV of an inflatable system generated by the application of an external force to the inflatable system when stationary according to claim 3, in which the extraction of the variation in internal pressure P' ends when the recorded internal pressure P changes direction of variation or after a duration TO corresponding to the end of the adiabatic transformation of the fluid.
6. Method for estimating the variation in AV volume of an inflatable system generated by the application of an external force to the inflatable system when stationary according to one of claims 1 to 5 in which, before the main step, the equipped inflatable system is in a thermomechanically stabilized state.
7. Method for estimating the variation in volume AV of an inflatable system generated by the application of an external force on the inflatable system when stationary according to one of claims 1 to 6, in which the temperature sensor and the pressure sensor are placed in a subspace of the closed fluid cavity delimited by the deformable surface of the inflation system.
8. Method for estimating the variation in AV volume of an inflatable system generated by the application of an external force to the inflatable system when stationary according to one of claims 1 to 7, in which the temperature sensor operates with a resolution of less than one hundredth of a degree.
9. Method for estimating the variation in AV volume of an inflatable system generated by the application of an external force to the inflatable system when stationary according to one of the Claims 1 to 8 wherein the pressure sensor operates with a resolution of less than a millibar.
10. Method for estimating the variation in volume AV of an inflatable system generated by the application of an external force to the inflatable system when stationary according to one of claims 1 to 9, in which the determination of the initial volume V0 takes into account the geometry of the deformable surface of the inflatable system inflated to a reference pressure PO, preferably the reference pressure PO is the initial pressure PI.
11. Method for estimating the variation in AV volume of an inflatable system generated by the application of an external force to the inflatable system when stationary according to claim 10 in which the geometry of the deformable surface is determined using an identifier of the inflatable system, preferably obtaining the identifier of the inflatable system is carried out by a radiofrequency interrogation of an electronic device located in the inflatable system.
12. Method for estimating the variation in volume AV of an inflatable system generated by the application of an external force on the inflatable system when stationary according to one of claims 1 to 11 in which the load Z of the equipped inflatable system is estimated by a relationship according to the following formula: Z = K PP * P * A(F) = Kp P * P * (Fl - FO) [MATH1] where Kpp is the pneumatic stiffness of the deformable surface of the inflatable system per unit volume.
13. Method for estimating the volume variation AV of an inflatable system generated by the application of an external force on the inflatable system when stationary according to one of claims 1 to 12 in which the volume variation AVl of the fluid cavity of the equipped inflatable system is estimated by solving the following differential equation: [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.
14. Method for evaluating the variation in load AZ applied to an inflatable system comprising the method for evaluating the variation in volume AV according to one of claims 1 to 13 in which the method comprises a step of determining the variation in load AZ using a function F of which at least one parameter is the variation in volume AV of the fluid cavity of the inflatable system, preferably the function F is defined by a relation according to the following formula: [MATH4] where KSG is the stiffness of the deformable surface of the inflatable system per unit volume.

Description

DESCRIPTION TITLE: METHOD FOR ESTIMATING THE VARIATION IN VOLUME OF AN INFLATABLE SYSTEM SUBJECTED TO AN EXTERNAL FORCE Field of invention [0001] The present invention relates to the field of real-time determination of the quasi-static volume variation of an inflatable system up to the load variation generated by the application of an external force to the inflatable system. Technological background [0002] Obtaining the volume variation of an inflatable system by applying an external force to the inflatable system makes it possible to determine the new stability condition of the inflatable system, in other words its new functional equilibrium point. Knowledge of this new equilibrium point makes it possible to identify the new functional characteristics of the inflatable system, thus making it possible to anticipate its thermomechanical capabilities in the context of its use within a more complex system. Thus, for an automobile, a tire or air suspension will change its thermomechanical properties depending on the volume variation generated by the application of an external force to the vehicle by coupling a trailer to the vehicle or boarding passengers within the vehicle. Thus, in order to optimize the functional organs of the vehicle, which are increasingly electronically configurable, knowledge of the thermomechanical properties of the tire, such as the dynamic rigidities of the tire, is desirable in order to adapt the laws of evolution of certain organs of the vehicle to these thermomechanical properties in order to improve passenger comfort and/or vehicle behavior. To date, the settings of these devices in vehicles are fixed according to the degree of wear and aging of the tire or air suspension, which is not optimal in all circumstances and over time. However, for an inflatable system, its thermomechanical properties are a function of the pressure, temperature and volume occupied by the fluid in these inflatable systems. While the measurement of temperature and pressure are easily accessible by dedicated sensors, the evolution of the volume of the fluid cavity of these inflatable systems is not easy. [0003] The objects and methods of the invention which follow aim to solve the problem of measuring the variation in volume of an inflatable system in the absence of a measuring system external to the inflatable system, i.e. usable at any time without specific measuring means within the inflatable system. In addition, this evaluation is carried out instantly, allowing a rapid decision to be made on the safety criterion of the inflatable system, such as the load carried by a vehicle tire before any movement of the vehicle. Description of the invention [0004] The invention relates to a method for estimating the variation in AV volume of an inflatable system generated by the application of an external force to the stationary inflatable system comprising the following steps: • In the preliminary phase, • Equip the inflatable system with at least one temperature sensor, said sensor being capable of measuring the internal temperature of the fluid cavity of the inflation system delimited by at least one deformable surface of the inflatable system; • Equip the inflatable system with at least one pressure sensor, said sensor being capable of measuring the internal pressure of the fluid cavity of the inflation system; • Determine the initial load ZI exerted on the deformable surface of the inflatable system; • Determine the initial inflation pressure PI of the fluid cavity of the inflatable system; • Determine the initial internal temperature Tl of the fluid cavity of the inflatable system; • Evaluate the initial volume VI of the fluid cavity of the inflatable system at T using a first function comprising as parameter the volume V0 of the fluid cavity of the unloaded inflatable system inflated to the initial pressure PI and the rigidity of the deformable surface of the inflatable system per unit volume Kp, • Evaluate the number of moles of fluid n in the fluid cavity of the inflatable system equipped from a model taking into account the inflation pressure PI, the initial volume VI, the temperature Tl; • In the main phase: • Apply the external force on the deformable surface of the inflatable system; • Record the internal temperature T of the fluid cavity of the equipped inflatable system at an acquisition frequency Fl; • Record the internal pressure P of the fluid cavity of the equipped inflatable system at a frequency F2; and • Evaluate a variation in volume AV of the equipped inflatable system using the recorded internal temperature T and the internal pressure P recorded using a fluid model in adiabatic transformation, the fluid having ideal gas behavior. [0005] According to a first preferred embodiment, in the preliminary phase, the method comprises a step of determining a law of evolution of the internal pressure P of the fluid cavity from the internal temperature T during an adiabatic transformation of the flui