Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C19/00—Tyre parts or constructions not otherwise provided for
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
  • B60C11/24—Wear-indicating arrangements
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
  • B60C11/24—Wear-indicating arrangements
  • B60C11/246—Tread wear monitoring systems
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C23/00—Devices for measuring, signalling, controlling, or distributing tyre pressure or temperature, specially adapted for mounting on vehicles; Arrangement of tyre inflating devices on vehicles, e.g. of pumps or of tanks; Tyre cooling arrangements
  • B60C23/02—Signalling devices actuated by tyre pressure
  • B60C23/04—Signalling devices actuated by tyre pressure mounted on the wheel or tyre
  • B60C23/0408—Signalling devices actuated by tyre pressure mounted on the wheel or tyre transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C19/00—Tyre parts or constructions not otherwise provided for
  • B60C2019/004—Tyre sensors other than for detecting tyre pressure
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T2210/00—Detection or estimation of road or environment conditions; Detection or estimation of road shapes
  • B60T2210/10—Detection or estimation of road conditions
  • B60T2210/13—Aquaplaning, hydroplaning

Definitions

• the invention relates to a method for monitoring a vehicle tire, a method for monitoring a vehicle, a method for generating a vehicle-tire interaction model, and a method for generating a vehicle-tire reliability map.
• the invention relates to a vehicle diagnostic system.
• the tires of the vehicle wheels convey the contact between the road and the vehicle. They are of crucial importance for the safety and comfort of the vehicle.
• the tire is a complex component, the service life of which depends on numerous factors.
• a critical parameter for the tire condition is in particular the temperature in the tire shoulder, that is to say in the area of the transition between the side wall and the tread. In the event of overuse due to excessive vehicle loading, high lateral forces or insufficient air pressure, there are severe deformations that lead to high temperatures. If certain critical temperatures are exceeded, irreversible damage to the tire occurs, which can lead to the loss of its functionality. This can be due to both faulty tire parameters, such as too low air pressure, and faulty vehicle parameters, such as incorrect setting of the camber or lane.
• the invention has for its object to provide a remedy for the problems mentioned above.
• a first solution of the invention object is achieved with a method for monitoring a vehicle tire according to claim 1.
• the method according to claim 8 is directed to a further method for solving the object of the invention.
• a solution to the problem of the invention is also achieved with the features of claim 9.
• a further solution to the object of the invention is achieved with a tire diagnostic system according to claim 10.
• the claim 11 characterizes a vehicle diagnostic system for solving the task of the invention.
• FIG. 1 shows a half cross section through a vehicle tire mounted on a rim
• FIG. 2 schematically the influence of temperature and time on the damage to a tire
• FIG. 3 influencing variables on a diagnostic model
• Fig. 4 is a sketch for explaining the function of an inventive
• 5 and 6 are a block diagram of a diagnostic system
• FIG. 7 shows a half cross section through a vehicle tire mounted on a rim and modified from that of FIG. 1 with parts of a vehicle monitoring system
• Fig. 13 schematically shows a sensor
• Fig. 1 shows a cross section through a known radial design tire, which has a carcass 4, which is composed for example of two radially extending layers of rayon threads and ends radially inwards in beads 6.
• a belt 10 is arranged on the radially outer area of the carcass 4 and consists, for example, of two crossed layers of steel threads and two circumferential layers of nylon threads.
• a rubber layer 12 is vulcanized over the carcass or the belt 10 and forms the tread 14 in the radially outer region and belongs to relatively thin side walls 16 in the lateral region.
• the beads 6 are received in shoulders 18 of a rim 20 which is part of a wheel, not shown.
• the tire is airtight so that its interior can be pressurized with compressed air via a valve 22 inserted into the rim.
• the construction is just for example.
• the invention described below can be used for different types of tires.
• the tire durability is given by the abrasion of the material of the tread 14, depending on the route, the loads and the air pressure.
• the wear of the tread 14 can be easily recognized visually. More problematic are not easily recognizable damage to the tire from the outside, which are essentially dependent on the heat converted in the tire by power loss. Temperatures in the region of the lateral edges of the belt 10, which are generally the highest temperatures occurring in the tire, are particularly critical. The reason for this is that different elements of the tire, such as belt, carcass, side wall, tread, come together and shift relative to one another when the tire is deformed. Depending on the height and duration, high temperatures in this area can lead to material damage or even detachments that irreversibly damage the tire.
• a direct loading Mood is possible by attaching at least one temperature sensor 24 in the area of the belt edges, which is connected, for example, to a transponder arranged in the tire, via which the temperature value can be transmitted to the outside without contact and can be recorded by a vehicle-mounted antenna.
• further sensors can be arranged which, for example, mechanically deform the tire in the area of the tread, the temperature of the tread, the air pressure inside the tire, the number of revolutions of the tire Detect tire etc. and their measured values can be transmitted to the outside in a contactless manner known per se.
• the energy supply to the associated transponders can be carried out in a contactless, electromagnetically known manner from the outside.
• FIG. 2 illustrates the influence of the temperature T measured in the area of the belt edges or the transition between the tread and the side wall in the tire shoulder on the tire damage.
• the curve S indicates damage which leads to a serious malfunction of the tire, ie to a tire that has to be replaced. If a temperature Tj is exceeded, this means an increased load on the tire, which leads to the permissible damage being reached if the exposure time ⁇ t is long enough. The permissible exposure time decreases with increasing temperature. If a temperature T 2 is exceeded, there is a special load on the tire, which leads to a failure of the tire after a relatively short period of time .DELTA.t. To monitor the tire, it is therefore necessary to know the temperatures and their durations, the individual damage components acting integrally, ie adding up to an overall damage.
• a tire damage model can be determined on the test bench, through practical test runs or through model calculations, which, for example, defines a damage value SW as an integral over the temperature T, optionally provided with a weighting parameter a (T), over the respective time period at which the temperature is present, the tire is irreversibly damaged as soon as this damage value exceeds a maximum value.
• the wear of a tire depends first of all on vehicle parameters FP, which are vehicle-specific and indicate such sizes as, for example, the wheel load or the axle kinematics, which has an influence on the tire stress during compression, when turning the steering, etc.
• vehicle parameters FP which are vehicle-specific and indicate such sizes as, for example, the wheel load or the axle kinematics, which has an influence on the tire stress during compression, when turning the steering, etc.
• the tire load is also influenced by vehicle setting parameters, such as setting the camber, the track or an imbalance.
• Vehicle operating parameters FB which characterize the operation of the respective vehicle, such as loading, speed, wheel speed, yaw rate, lateral acceleration, slip, steering angle and slip, also have an influence on the tire stress.
• tire wear depends on vehicle setting parameters FE, such as camber, track, unbalance.
• Tire wear also depends on the respective tire itself, the parameters RP of which are incorporated into a tire wear or diagnostic model as type, size, DOT and the age of the tire and its mileage already traveled.
• the air pressure or the tire inflation pressure influences the wear of the tire, which is set, for example, at an air refill station in accordance with the operating instructions of the vehicle.
• the environmental parameters UP have an impact on tire wear, such as air temperature, wheelhouse temperature, ground or road temperature, sun intensity, etc.
• a diagnostic model can be derived from the parameters mentioned on the basis of model calculations and / or driving tests, which directly calculates tire wear and / or damage and / or can be calculated from the variables that are decisive for tire damage, such as the temperature of the belt edge, Temperature of the tread, average tire temperature, heat dissipation implemented in the tire, air pressure and expansion dynamically occurring in the tire or mechanical stress of the tire.
• the right-hand tire operating parameters RP can be calculated from the left-hand parameters using model calculations, which may be validated with test bench tests or derived from test bench tests:
• the damage value SW can be calculated.
• Some of the calculated tire operating parameters can additionally be measured directly on the tire by means of sensors, as explained with reference to FIG. 1, and compared in the diagnostic model with the calculated values, so that an adaptation of the diagnostic model is possible.
• the diagnostic model which indicates the relationships between the individual values of the parameters in the form of maps, algorithms, etc., can be used in both directions. If the parameter values on the left in FIG. 3 are known, the tire wear and / or a damage value of the tire can be calculated, wherein the reaching of a critical damage value can be indicated. Conversely, the parameter values shown on the right in FIG. 3 can be measured or determined indirectly, so that parameters from the left-hand side, in particular for example the vehicle setting parameters camber and lane, can be inferred from the diagnostic model, so that errors in the driving from the diagnostic model and the measurement of the tire operating parameters as well as further vehicle operating parameters and possibly environmental parameters can be recognized, displayed and corrected.
• the diagnostic model can be more or less detailed depending on the hardware complexity (number of sensors used) and software complexity.
• the vehicle operating parameters are constantly known, in particular in vehicles equipped with driving stability systems. The same applies to the tire parameters and the ambient air temperature parameters, as well as to the vehicle parameters, to which the target values of camber and lane can also be included.
• the tire operating parameters can be calculated from these data on the basis of the diagnostic model, it being expedient for the constant review of the diagnostic model to measure at least one of the tire operating parameters on the tire and to compare it with the calculated value. Constants or dependencies used in the diagnostic model are then adapted accordingly, so that the diagnostic model and its input variables, for example the mileage of the tire, are continuously updated. The more tire operating parameters on the right-hand side (FIG.
• FIG. 4 illustrates the function of a diagnostic system that works with the diagnostic model of FIG. 3.
• Some vehicle parameters are only shown as examples on the left. Some tire parameters are listed on the right as an example.
• the parameters on the left are fed to an evaluation unit 28, which in a manner known per se contains a microprocessor with associated memory devices in which the diagnostic model is stored, for example via a data bus 30.
• the tire parameters such as temperature, speed of rotation of the tire, and an identification code for identifying the tire, are transmitted to the expansion unit 28 from the respective tire via a contactless data transmission.
• distance 32 fed can take place, for example, according to the RFID method (radio frequency identification).
• warnings can be generated in the evaluation unit, which indicate faulty vehicle setting parameters, such as camber, toe or a worn or damaged tire.
• predictive values can be generated with regard to the tire over the remaining running time or damage that can still be used up, in order to ensure that the tire is changed in good time.
• the values of the tire-related parameters calculated in the diagnostic model can be transferred into the tire via the data transfer route 32 and can be stored there on a corresponding storage medium. In this way, each tire carries its data relevant for the assessment, which can be read out immediately.
• Figures 5 and 6 show a block diagram of a diagnostic system in an extensive construction stage.
• tire sensors 34 variables such as tire temperatures, wheel speeds, tire air pressure, vibrations or accelerations on the wheel and / or the contact force, the wheel load and / or deformations of the tire are recorded and fed to a tire data unit 38 via a data transmission system, generally referred to as tire sensor system 36 at least some of the tire operating parameters RB in FIG. 3 and tire setting parameters RE are determined and the tire parameters RP are stored. The determined and stored parameters are fed to an operating data unit 40.
• tire sensor system 36 at least some of the tire operating parameters RB in FIG. 3 and tire setting parameters RE are determined and the tire parameters RP are stored.
• the determined and stored parameters are fed to an operating data unit 40.
• variables are recorded, such as outside temperatures, the position of the sun, the intensity of the sun, wheel speeds and slip, variables relating to driving dynamics, such as steering angle, yaw rate, wheel position, speed, lateral acceleration and engine data, such as the torque.
• driving dynamics such as steering angle, yaw rate, wheel position, speed, lateral acceleration and engine data, such as the torque.
• vehicle data unit 46 supplied to a vehicle data unit 46 via a data transmission device designated as a vehicle sensor system 44, in which all or some of the vehicle operating parameters FB (FIG. 3), vehicle setting parameters FE, vehicle parameters FP and environmental parameters UP are determined, or as far as vehicle-specific, are saved beforehand.
• the parameters mentioned arrive in the operating data unit 40, which is connected to the computing and evaluation unit 28 (see also FIG. 4).
• the diagnostic system designated as a whole by 50, has warning and signaling devices 52, with which fault messages can be triggered immediately, for example, when the temperature in the tire is inadmissibly high.
• 5 mainly describes the sensory part of the diagnostic system.
• 6 mainly describes the simulation-related part of the diagnostic system 50.
• Vehicle operating parameters FB (FIG. 3) are input into a vehicle operating parameter unit 58.
• the vehicle parameters FE, FP are input into a vehicle parameter unit 60.
• the tire parameters RP are input into a tire parameter unit 62.
• the parameters mentioned can likewise already be contained in the tire data unit 38 and the vehicle data unit 46.
• a calculation unit 64 the forces and moments (66) effective in the tires are calculated from the data of the units 58, 60 and 62 with the aid of a model calculation, on the basis of which the power loss and the temperatures of the tire 70 are calculated in a tire power loss model 68.
• the respective ambient conditions are taken into account in an ambient temperature model 72, which can be connected to the air conditioning sensors via the dotted line, so that the variables calculated in the unit 70 can be corrected and in the virtual map unit 74 the tire power loss and the temperature distribution in the tire due to the adopted models can be calculated.
• test bench test 76 with a test vehicle 60 'corresponding to the vehicle parameters and equipped with tires 62' corresponding to the tire parameters, tests are carried out which correspond to the vehicle operating parameters and the power loss and the tire temperature distribution (78) are measured ,
• a simulation calculation (80) carried out taking into account the vehicle operating, vehicle and tire parameters, in which the tire temperatures and the power losses are also calculated, can be adapted on the basis of the test bench results, whereby the results can also be used to modify the model on which the calculation unit 64 is based ,
• results 78 can be used to generate a temperature and power loss map 78 or 82 which, taking environmental conditions (84) into account, leads to a real temperature and power loss map (86 ) can be converted, the real maps of the unit 86, in contrast to the virtual maps of the unit 74, being determined on the basis of test results.
• the two characteristic diagrams are combined in unit 88 to form an interaction model that combines tire-type-specific data with vehicle-specific data.
• Data calculated in the interaction model 88 can be supplemented with data from the vehicle operating parameter unit 46.
• a comparison unit 90 actual data from the operating data unit 40 can be compared with calculated target data from the unit 88. In the event of a deviation, a warning message can be generated immediately.
• characteristic diagrams or computing algorithms are generated in a characteristic diagram unit 90, which link the individual parameters with one another in accordance with tire-type-specific basic data and vehicle data.
• tire-type-specific reliability and service life models are derived in the unit 94, which are fed together with the characteristic maps of the unit 90 to the computing and evaluation unit 28, in which all There are links that are contained in systems of equations 1, 2 and 3, for example.
• the described diagnostic system can be used and modified in a variety of ways.
• the tire type-specific tire-vehicle interaction model 88 which collectively tion of the computing and evaluating unit 28 can be developed predominantly virtually (left branch of FIG. 6) or predominantly using real tests (right branch of FIG. 6) or by a combination of both methods.
• the tire temperatures or power losses predicted or calculated for a specific vehicle / tire combination with different parameter settings (loads) can be compared with the service life of the corresponding tire to be expected under these conditions (damage comparison). This results in the possibility of assessing the robustness of the tire in comparison with the loads to be expected in operation in combination with a specific type of vehicle.
• the design of tires and the coordination with the vehicle can be taken into account and tested at very early stages, especially if virtual methods are used to determine the maps before the first vehicle or tire pattern is available.
• the map-protected and model-protected development of the tire temperature and power loss enables the simulation of simultaneous adjustment of the temperature-dependent tire properties in tire simulation models that are indirect (e.g. when changing the interior air pressure kes) or directly (e.g. by changing the stiffness or the coefficient of friction) on driving behavior and performance (traction or transfer of lateral forces).
• the interaction model 88 can thus not only be used advantageously within the diagnostic system. It is also a development tool that can be used to advantage in the design of a tire for certain vehicles or vehicle types, for example, depending on the parameters of the tire and the vehicle, with which simulation calculations and test bench tests are based on the vehicle operating parameters for the tire damage and thus determine the durability of the tire relevant parameters.
• the tire type-specific reliability map (block 94) is determined from the test bench tests (block 92) with the tires operated under a predetermined load.
• the connection line contained in FIG. 6 to blocks 78 and 92 indicates, as already explained above, that the result matrix (block 78) can be used as the basis for the test bench tests (block 92).
• the tire type-specific reliability map / service life model (block 94), analogous to a strength map of mechanical components, indicates the service life of the tire in relation to the operating temperature as a load variable in the form of characteristic curves, as are shown, for example, in FIG. 2. This means that precise information about its service life and reliability can be made as early as the development phase of a tire.
• the speed of a tire can be determined directly using the tire sensor system or indirectly via the vehicle sensor system.
• sun intensity that is, the irradiated power per unit area
• the ambient temperature model works in the direct vicinity of the tire with a sufficiently good approximation, which assumes that the ambient temperature is a mean value of the ground temperature and the air temperature.
• the invention provides a flexibly usable diagnostic system, which enables warnings of dangerous conditions and a query of predicted remaining operating times or incorrect settings both in the vehicle via the sensors and the evaluation unit located there, and can also be read out in a workshop in order to Determine the maintenance needs of the vehicle.
• the maps, algorithms and dependencies used in the diagnostic model can be determined experimentally and / or obtained by simulation, CAD / FEM calculation, etc.
• sensors are used as sensors, such as temperature and pressure sensors, speed, speed, mileage, yaw rate sensors, etc.
• non-contact methods are used, for example based on inductive energy transmission and HF Technology.
• One of the key elements of the diagnostic system according to the invention is a sensor transponder unit applied in the tire, with which the operating parameters of the tire, such as internal air pressure, temperatures at various points, strains, forces, acceleration, etc., are recorded and advantageously transmitted to the evaluation unit in the vehicle in a contactless manner can be.
• FIG. 7 shows a view similar to FIG. 1 of a tire in which a sensor network 124 is arranged between the belt 10 and the carcass 4, for example laminated or vulcanized. is cannulated, which contains sensor units, not shown in FIG. 7.
• the sensor units can be read out by means of a vehicle-mounted antenna 126, which is connected via a data line 32 to a control unit 28 or an evaluation unit 28 (FIG. 4), the further inputs and outputs connected to vehicle sensors or other control units can have and is connected to the vehicle bus system 30 (FIG. 4).
• FIG. 8 schematically shows three antennas 126 which are spaced apart in the circumferential direction in a fender of a vehicle and, if necessary, also offset in the transverse direction of the vehicle, and which communicate with at least one transponder 136 contained in the sensor network 124 or with a transponder 136 connected to a node of the sensor network.
• the transponder or transponders more or less fixed antennas can be provided.
• FIGS. 9 to 11 show views of the sensor network 124 with the belt 10 located underneath from the inside of the tire.
• sensor units 138 contained in the sensor network 124 are each connected via a line 140 to a node 142 which contains the transponder 136.
• a plurality of sensors 138 arranged in series one behind the other are each connected to the transponder 136 via a common line 140.
• FIG. 11 shows an embodiment in which the lines 140 form a diamond-shaped network 141, which is connected to the node 142 with the transponder 136.
• the thread-like lines 140 advantageously consist of steel cable, carbon, conductive plastic and other electrical conductors known, for example, from aerospace, which are combined with other materials or fibers for the necessary insulation and strain relief, for example carbon, aramid, steel cable plastic, conductive plastic. Ceramic fiber, etc., whereby the composite threads or lines must be resistant to chemicals and heat in order not to be damaged when the tire is vulcanized, and mechanically see must have properties that withstand the stresses in the operation of the tire.
• each sensor unit 138 is connected to the central node 142 via one or more electrically insulated lines or are used jointly by the individual sensor units if the sensor units have their own processors, for example, and are used individually in multiplex or bus technology Transponder 136 can be queried.
• the circuit arrangements of FIGS. 8 or 9 can thus be implemented within the conductor or thread network 141.
• a conductor or thread network 141 is produced from the necessary conductors 140, which, equipped with the sensor units 138, forms the sensor network 124, which is arranged between the belt 10 and the carcass 4 and is vulcanized in the manufacture of the tire.
• the width of the sensor network 124 which is somewhat larger in FIG. 1 than that of the carcass 10, can, depending on the desired sensor units, extend into the side walls 16 or not completely cover the belt 10.
• the sensor network 124 does not necessarily have to extend around the entire circumference of the tire (viewed in the direction of travel thereof).
• the individual threads of the network can be multi-core.
• a mass for all sensor units 138 and transponder 136 can be formed by the steel position of belt 10, with which each sensor unit and transponder 136 are conductively connected.
• the node 142 forms, for example, a base substrate with conductor tracks for connecting the conductors 140 and the elements of the transponder, such as processor, memory, antenna and possibly energy supply, applied to the base substrate.
• mechanically stable threads can extend through the entire substrate or can be connected to expansion elements for force measurement, which are integrated in the substrate.
• the sensor units 138 can be of the most varied types depending on the physical quantities or operating parameters of the tire to be determined.
• the sensor units 138 can contain a plurality of sensor elements, for example one for measuring the temperature, one for measuring the tire air pressure, one for measuring the pressure acting from the belt, and strain measuring cells for measuring the forces acting on the threads or Strains (Fig. 11), which are a measure of the local strain of the tire structure.
• the information is available in a form that allows a representation of the respective measured size over the respective area. As will be explained below, these representations can be used in a variety of ways.
• Pressure measurements can be carried out, for example, using pressure-sensitive foils or micro measuring cells with piezo elements or capacitors. Strains in the tire structure can be measured with strain-sensitive foils or micro measuring cells (piezoelectric or according to the capacitor principle). The temperature distribution can be carried out in a similar manner piezoelectrically, by means of resistance measuring elements, etc. The measuring principles are known per se and are therefore not explained.
• FIG. 12 schematically shows a sensor unit 138 with a temperature measuring element 144, a pressure measuring element 146 and two strain measuring elements 148 and 150 arranged perpendicular to one another.
• transponder 136 which is assigned to the node 142 to which the sensor units 138 are connected.
• the transponder 136 is inductively supplied with current each time it moves past one of the antennas 126. It goes without saying that the transponder 136 is advantageously not arranged directly under the belt 10, but laterally next to the belt, so that it is not shielded from the antenna or antennas 26.
• the data transmission from the transponder 136 via the antenna or antennas 126 to the control device 128 can take place online by reading out one of the sensor units; in another method, the data of the individual sensor units are cyclically read in, buffer-stored and then read out, for example according to a sample-hold method, in a memory controlled by the processor of the transponder.
• the sensor units can be read out in a time- or speed-controlled manner.
• Transponders and the associated transmission technologies are known per se, so that they are not explained in detail. For example, a temperature value, pressure value, an elongation, etc. of a sensor can be read out for each wheel revolution, so that a complete image of the tire is obtained after a corresponding number of revolutions.
• Reading out the data via a transponder which is carried out by means of appropriate electronic equipment (memory, processor) via data processing capacity, is not mandatory.
• the individual sensor elements can, for example, have resonant circuits with sensor-specific resonance frequencies, so that the sensors can be read out directly in a frequency-specific manner.
• the measurement signal can be given by detuning the resonance frequency or by modulating the resonance frequency. With this type of data transmission, the central node 142 with the central transponder 136 assigned to it is not necessary.
• the thread or line network 141 is not mandatory. With the increasing miniaturization of transponders, in which sensor elements are integrated and which are bendable or flexible overall, and the low costs, it is possible to arrange a large number of individual sensor units with integrated transponders and, if necessary, additional own energy supply in the tire at appropriate locations and without contact read.
• Such flexible plastic chips with sufficient temperature resistance are described, for example, in the article by F. Miller “Polytronic: Chips from the Roll", Fraunhofer Magazin 4, 2001, pp. 8-12. Such chips can be inserted individually into the tire or arranged as a prefabricated assembly on a thread network.
• the control unit has a microprocessor and memory units, so that the operation of a read-out unit and evaluation unit contained in it is controlled and results are displayed on a display unit.
• the temperature profile of the tire can be stored, the decisive factor for the service life or damage to the tire is how long a temperature above a threshold value is present at one point on the tire shoulder. Insufficient air pressure in the tire can be inferred from an impermissibly high temperature.
• the invention not only opens up the possibility of detecting the static and dynamic stresses of the tire, and of determining its power loss; monitor the functionality of the tire and forecast its service life, but also the possibility of inferring errors on the vehicle from the evaluation of the ascertainable detailed tire data and monitoring their condition.
• the revolution measuring unit 152 contains a sensor element 154, which emits a signal every revolution of the tire.
• the sensor element 154 can contain, for example, a piezo element against which an inert mass with fluctuating force presses when the tire rotates, so that a voltage signal tapping at sensor element 154 fluctuates.
• the output signal of the sensor element 154 can be evaluated for energy supply, which energy is appropriately processed in a power supply unit 156, and can further be used to generate a signal that is integrated into the revolutions of the tire, in that each fluctuation in the output signal of the sensor element 154 caused by one rotation unites Count of a storage unit 158 increased by one.
• the tire itself contains a signal which, regardless of which vehicles the tire was used on, indicates the number of revolutions that the tire has traveled.
• the count of the storage unit 158 can be read out in workshops for this purpose. For security against manipulation, a reset of the storage unit 158 is not possible or only possible at particularly authorized locations.
• the revolution measuring unit can be integrated into a rim-fixed valve (e.g. valve 22 in FIG. 1).
• the sensors 138 and / or the transponder 143 can also be supplied with energy generated from the rotation of the tire.
• memory elements can be provided in which certain parameters critical to the condition of the tire are stored in the tire itself, so that quality monitoring of the tire, for example damage to the flanks or mechanical overloading of the tire itself, can be recognized by reading out the corresponding data memory.
• the warning messages (52 in FIG. 5) can be divided into two levels, namely warning of singular faults, such as incorrect tire pressure, incorrect axle settings, excessive wheel load, etc., or warning of combined faults in which several faults are superimposed and their mutual interactions can also create dangerous operating conditions, for example, incorrect wheel settings (camber, lane), high wheel loads can have an increased impact on the tire temperature.
• singular faults such as incorrect tire pressure, incorrect axle settings, excessive wheel load, etc.
• warning of combined faults in which several faults are superimposed and their mutual interactions can also create dangerous operating conditions, for example, incorrect wheel settings (camber, lane), high wheel loads can have an increased impact on the tire temperature.
• the described diagnostic system can be expanded by vibrations of the tire during driving operation by a warning possibility which recognizes an occurring or already occurred damage of the tire on the basis of the vibration course.
• the maps stored in the diagnostic system are preferably multidimensional, for example maps can be stored for the tire temperature, which maps the temperature as a function of camber, lane, weights, load distributions and ambient conditions as well as the current driving dynamics parameters such as speed, yaw rate.
• the minimal solution is suitable for determining the residual damage on the basis of the belt edge temperature and its time shares.
• the hardware equipment includes sensors for the tire belt edge temperature, the time and advantageously the running distance, a transmission unit, an evaluation unit with memory function and a warning device.
• the evaluation unit contains the characteristic map of the respective tire with regard to the belt edge temperature and its time components as well as the maximum possible damage or running distance.
• the sensors for the belt edge temperature are dispensed with and this variable is carried out arithmetically on the basis of the values of the relevant parameters.
• the power loss is the difference between the input and output power
• the power loss P loss can be broken down into 6 main components:
• roll x coordinate in the direction of the vehicle front (longitudinal)
• y coordinate in the direction of the vehicle side (lateral)
• z coordinate in the direction perpendicular to the top of the vehicle (vertical)
• the power loss can thus be calculated from purely mechanical parameters.
• M is the mass of the tire and c is the heat capacity of the tire.
• ⁇ 5,671E-08 W / (m K 4 ) the radiation constant
• ⁇ 0.95 the heat transfer coefficient of rubber
• T B the temperature of the ground
• a 2 the surface of the tire.
• the quasi-stationary end value of the tire temperature T R then results from an iterative calculation algorithm for solving the heat balance equation for a time t which is sufficiently long with regard to the transient process of the overall system.
• a, b, c, d, K and N are the type-specific parameters from map matrices, which are obtained by experiment or simulation.
• K can take the form of a constant correction term as well as a variable with combinations of several of the other parameters - also of higher order.
• the power loss P loss results, for example, from the model explained under A, which Ambient parameters of street or soil temperature T soil , air inflow temperature T inflow and solar radiation power P radiation (in the heat balance equation : P 0 ) result from measurements or from parameter estimates via databases or correlation models.
• the power loss P loss can alternatively also be based on a further empirical approach, for example the shape
• camber camber adjustment
• toe toe-in adjustment
• pressure tire air pressure
• Load load / tire vertical force
• Speed driving speed
• the characteristic values can either be measured data from test series or parameter estimates, e.g. be from driving dynamics regulations.
• K is the parameters from type-specific map matrices, which are obtained by experiment or simulation.
• K can take the form of a constant correction term as well as a variable with combinations of several of the other parameters - also of higher order.
• the empirical / statistical temperature model can also be used as a normalization model or correction model to take the environmental conditions into account.
• the above formula P gives a simple possibility for power dissipation calculation.
• the parameters s, t, p, 1, v, K represent the characteristic variable “power loss” N.
• the vehicle parameters FE, FP camber, toe, wheel load
• the vehicle operating parameters FP for example speed
• the tire parameters RP for example type
• tire setting parameters for example air pressure
• the power loss P loss thus calculated is used in the formula T for the tire temperature T R given above.
• the parameters a, b, c, d, K and N are known from the tire-type-specific vehicle interaction model 88 as a result of the virtual map determination 74 or real map determination 86, in each case for the parameter “temperature”.
• the environmental parameters UP such as T floor , T air flow , P radiation, are available, for example, from the data from vehicle sensors 44/42 (FIG. 5).
• a vehicle setting parameter FE e.g. the camber can be estimated by calculation in that the temperature map stored in the tire-type-specific vehicle-tire interaction model 88 (FIG. 6) shows the known temperature in the belt edge and additionally the necessarily known tire parameters RP and at least one further vehicle parameter FE, FP and Vehicle operating parameters FB are used.
• the diagnostic system described also opens up the possibility, after detection of the over- exceeding permissible values, for example in the case of tire operating parameters, to initiate suitable countermeasures with the help of an active or passive technical device.
• the tire temperature can be limited by changing the air flow (increasing the air speed and / or directing the air flow) in the vicinity of the tire by means of extendable aerodynamic guide devices (wings / slots) or by targeted cooling with an outflowing gas of low temperature.
• a low temperature gas can be generated on board by flowing an expanding, previously liquefied compressed gas onto the tire or from an air flow cooled by a heat exchanger, as is used in a similar manner to vehicle air conditioning.
• Another way to counteract an impermissibly high tire temperature is to increase the tire air pressure while driving in order to reduce the mechanical power loss converted into heat.
• a method for thermal conditioning of the operating environment in the vicinity of the tire is also possible in this way, to operate the tire in a thermally optimal working area.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Tires In General (AREA)
• Arrangements For Transmission Of Measured Signals (AREA)
• Measuring Fluid Pressure (AREA)

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• 2002
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