AU2018356859B2

AU2018356859B2 - Method for evaluating the performances of a tyre during use

Info

Publication number: AU2018356859B2
Application number: AU2018356859A
Authority: AU
Inventors: Nicolas Besnard; Olivier SPINNLER
Original assignee: Compagnie Generale des Etablissements Michelin SCA
Current assignee: Compagnie Generale des Etablissements Michelin SCA
Priority date: 2017-10-26
Filing date: 2018-10-25
Publication date: 2024-02-29
Anticipated expiration: 2038-10-25
Also published as: CL2020001081A1; WO2019081857A1; BR112020006274A2; CA3073917A1; CA3073917C; AU2018356859A1

Abstract

A method for determining a Tonne Kilometre Per Hour (TKPH) index of a tyre equipping a vehicle carrying out a plurality of rolling cycles when loaded and unloaded, in which the following steps are carried out: - Step A: for each cycle, acquiring data relating to the distance travelled when unloaded (

Description

METHOD FOR EVALUATING THE PERFORMANCES OF A TYRE DURING USE

[001] The invention relates to a method for estimating the performance of a tyre during use.

[002] Although not limited to this domain, the invention is more specifically concerned with the operation of civil engineering works tyres, particularly the tyres used on transport equipment of the dumper type in mines or in quarries.

[003] The particular features of these tyres is that they transport heavy loads at high speed over significant distances and that they run on ground that is often aggressive. This then results in an increase in temperature within the materials of which the tyre is formed, which increases liable to cause degradation to the tyre itself and place it out of action.

[004] So, users of such equipment, mindful of the productivity of their operations, pay particular attention to all the data originating from vehicles while they are running and which are liable to keep them informed of load or speed limits not to be exceeded.

[005] Numerous methods, associated with measurement devices, are available to them.

[006] Included among these methods are direct methods that allow the temperature of the materials to be evaluated. A method of this type is thus described in publication W02016151226.

[007] Other, more indirect, methods use the indications provided by the tyre manufacturer with reference to load and speed values not to be exceeded.

[008] Alternatively, one index often used is the Tonnes Kilometres per Hour index, more commonly referred to as TKPH, which is established by the manufacturer for a particular operating point of the tyre and which is based on knowledge of the limit temperature not to be exceeded in the tyre.

[009] This index is equal to the product of the mean load Qm borne by the tyre during a representative cycle and of the mean speed Vm during this cycle.

TKPHB = Qm X Vm

[0010] The mine and quarry operators thus calculate this index in order to ensure that the vehicle, and its tyres, remain within the limits specified by the tyre manufacturer.

[0011] This index exists in several forms in order to take account of the actual operating conditions. Thus, corrective coefficients are applied in order to make it possible to calculate a consistent parameter that allows an actual TKPH to be compared with the maximum TKPH obtained under stabilized and standardized running conditions and communicated by the tyre manufacturer. These corrective coefficients take account for example of the length of the cycle or else of the outside temperature.

[0012] However, the TKPH is, as a general rule, calculated at the end of each cycle without taking account of the values obtained in the previous cycles. In addition, the mean load and speed values used neglect observed variations associated with the stoppage times, the transient conditions or the temporary overloading observed during the cycle.

[0013] Embodiments of the present invention seek to provide a method for calculating the TKPH that makes it possible to obtain in real-time a value that is more objective so as to allow the operator to make optimum use of the tyres fitted to his vehicles.

[0014] In one aspect of the present invention, there is provided a method for determining a Tonne Kilometre Per Hour (TKPH) index for a tyre fitted to a vehicle effecting a plurality of running cycles laden and unladen. According to this method, the following steps are performed: - Step A : acquiring, for each cycle, the data relating to the distance covered unladen (Li), the distance covered laden (L2), the load borne unladen (Q1), and laden (Q2), and the total cycle time (TTC), and determining a value for the baseline TKPH (TKPHB):

TKPH_- QXL+Q 2 xL 2 TTC

- Step B: determining a value for the actual TKPH (TKPH) by multiplying the baseline product TKPH (TKPHB) by corrective coefficients (K2, R1), TKPHR = TKPHB x K2 x R1

- Step C : determining an integrated TKPH value (TKPH) by calculating a moving average, weighted over the plurality (n) of cycles performed during an earlier duration equal to a given integration duration (DI), of the actual TKPH values calculated for each of these cycles: TKPHJ= >-O(TTCi x TKPHR,) DI - Step D : comparing the value of the integrated TKPH (TKPH) with a stabilized maximum TKPH value permissible for the tyre (TKPHax), in order to adjust the conditions of operation of the vehicle or generate an alert if this is exceeded.

[0015] Calculating an integrated TKPH makes it possible to take account of the thermal history of the tyre in the cycles preceding the cycle observed, and during which the running or stoppage, laden or unladen times may have varied.

[0016] Through a careful choice of the values for the corrective coefficients R1 and K2, and that of the integration duration DI as will be seen later, this method offers the advantage, using a simple calculation that requires the acquisition of very little external data, of affording a good evaluation of the TKPH of a tyre while it is being operated over a plurality of cycles. Using a simple and known relationship, it is then possible to calculate, should the need to do so be felt, the actual temperature in the crown region, which is the region of the tyre that experiences the greatest heating.

[0017] The operator thus has access, at the end of each cycle, to a value that is a more precise approximation of the conditions of use of his vehicles and of the tyres with which they are fitted. He can then intervene on the operating parameters by altering the load or the speed of the truck, or by incorporating longer stoppage times.

[0018] In some embodiments, the method according to the invention may also comprise, alone or in combination, carrying out the following actions: - In step C, o determining an additional time (dt) such that the sum of the cycle times, increased by the additional time, is equal to the integration duration (DI= E=o(TTCj) + dt)) then, o in order to calculate the value of the integrated TKPH, (TKPH), increasing the sum of the products of the cycle times multiplied by the actual TKPH values (EnO(TTCi x) TKPHR) by the value of the product of the actual TKPH (TKPHRO) of the earliest cycle (io) over the integration duration (D) considered multiplied by the additional time (dt)

TKPHJ > i=1 (TTCi x TKPHR.) + dt x TKPHRo DI - In step B, the coefficient K2 is given by a first experimental law dependent on the ambient temperature of the outside air(ami)around the truck during the running cycle. - The first experimental law is of the type:

K2 -m )

m

in which the value of the coefficient m is comprised between 60 and 90. - The coefficient R1 is given, for a given running cycle, by a second experimental law dependent on the values observed during this cycle, on the unladen running time (t'), on the unladen stoppage time (t'), on the laden running time (t2), on the laden stoppage time t , and on the value of the integration duration (DO. - The second experimental law is of the type:

[ 2*t2 rt't 2*t2] 2*t,2 r21

[t~ ~ ++~ 1~eDI]l * eDI DI DT 1eDI]*eD

[ lt+t2 I2*tr 2*t,2 t~ 2 2* -2t4+*~t ~ 1-eI DI DI DI 1-e DI DI+DIIJ

in which the value of the coefficient n is comprised between 0.5 and 0.75.

- In step C, upon starting of the vehicle, and after a stoppage time greater than a first predetermined limit (T 1;2), the integrated TKPH, (TKPH ), 1 is determined for a duration equal to the integration duration (DI), on the basis of the (i) cycles performed, counted from the restarting of the vehicle, using the following law: >Z'O(TTCk x TKPHRk) TKPHI(i) = DI - The value of the first time limit (T2)is equal to the value of the integration duration multiplied by a coefficient p (T1 =p*DI), where the value of p is comprised between 2 and 5. - When the vehicle is stopped for duration greater than a second predetermined limit (T2,n2) and less than the first predetermined limit (T ii2) 1 , the TKPH at the end of the stoppage time ((TKPH(A)) is determined as a function of the integrated TKPH calculated for the last cycle before the stoppage (TKPH(to)), of the duration of the stoppage (t-to) and of the value of the integration duration DI, using a third experimental law of the type: 2(ti-to) TKP H1(A)= TKPH1(to) x e q*DI

in which the value of the coefficient q is comprised between 2 and 5. - When the vehicle restarts, the integrated TKPH, (TKPHj(i)), for a duration equal to the integration duration (DI), is determined on the basis of the (i) cycles performed, counted from the restarting of the vehicle, as a function of the integrated TKPH ((TKPH(A)) determined at the moment of the end of the stoppage time of the vehicle, of the integration duration (DI), and of the stoppage time (t-to) , using a fourth experimental law of the type: k=O(TTCk x TKPHRk) 10 TKPH 1(i)= ( DI + TKPH1(A) x (1 - tI DI - The integration duration (DI) corresponds to a multiple (k), comprised between 1 and 3, of a time (T) representative of the tyre temperature-rise time (DI = k * T).

- The integration duration (DI) is equal to twice the value (T) representative of the tyre temperature-rise time (DI= 2* T). - The integration duration (DI) is equal to the sum of the cycle times observed during the said integration duration (DI = yjo(TTCi)). - The tyre is mounted on a civil engineering equipment where the integration duration (DI) is comprised between 5 hours and 15 hours.

[0019] In a second aspect of the present invention, there is provided a device for implementing the method provided in accordance to the first aspect, the device comprising: - means for exchanging data with sensors (3) able to acquire values for temperature (0am,), for cycle time or cycle duration (t1,t1, t2, t, ,to),forload(QQ2) and for distance (L,, L2 ), that are to be processed, - at least one computer processing unit (2), and - coded instructions allowing the steps of the method to be executed.

[0020] In a third aspect of the present invention, there is provided a software containing the programmed code elements for running the method according to the first aspect when the said software is loaded into a computer processing unit and executed by the said processing unit, as well as the software, when the latter is in the form of a product recorded on a medium readable by a computer processing unit, containing the said programmed code elements.

[0021] The invention will be better understood from reading the following description and from the appended figures, which are provided by way of entirely nonlimiting example, in which: - Figure 1 depicts a dumper on which civil engineering tyres are fitted. - Figure 2 depicts a curve of the change in temperature of the crown of the tyre. - Figure 3 represents TKPH values obtained during the course of successive cycles.

[0022] The vehicle 10 illustrated in Figure 1 schematically depicts a site vehicle of dumper type commonly used in mines or quarries for transporting ores on the surface. This vehicle is equipped with means (30) for exchanging data with sensors (31, 32) able to acquire values for temperature (eami)31, for laden or unladen cycle time or cycle duration (t1, t1, t2, t2, ti, to), for load (Q', Q2) 32 and for distance (L,, L2 ). These sensors are generally routinely available on site vehicles and by default may undergo specific adaptation when the operator wishes to access finer detail of these values. They may equally come from external data such as GPS data, or else be the result of suitable analytical tools.

[0023] The vehicle also comprises a computer processing unit 20 able in real time or on demand to perform the operations and calculations that allow the TKPH to be obtained. It will be noted here that the calculation means are located in the dumper. As an equivalent, these data may be sent over a microwave radio channel, such as a Bluetooth or a 3G or 4G-type link, to a centre of operations housing computer processing units able to perform these same calculations and to transmit the operating orders to the drivers of the vehicles.

[0024] At the end of each cycle it is therefore possible to determine the integrated TKPH (TKPH) by performing the following steps.

[0025] The first step A consists in calculating a baseline TKPH, TKPHB

TTC TKPHB = in which formula Q, represents the load borne by the tyre when the vehicle is running unladen, and Q2 represents the load borne by the tyre when the vehicle is running bearing its commercial load, and in which L represents the distance covered unladen and L2 the distance covered when laden. TTC represents the total cycle time. This form of calculation makes it possible to differentiate between time spent running laden and time spent running unladen, rather than adopting mean values as is commonly done at present.

[0026] The next step B consists in weighting this first baseline TKPH to take account of the actual conditions of operation by multiplying this value by coefficients K2 and R1, which respectively signify the outside temperature and the stopping times, laden and unladen, observed during the cycle. This yields an actual TKPH, TKPHR, representing the conditions of operation during the cycle considered.

TKPHR = TKPHB x K2 x R1

[0027] These of coefficients are obtained experimentally and may be accessible via look up tables, via curves or charts, or else via equations that reflect the experimental curves obtained after numerous tests.

[0028] The value of the coefficient K2 may be obtained using a first experimental law of the type: K2 = 9 -_ ) (1)

Where ame represents the value of the main ambient temperature of the air for the duration of the cycle considered, and where m represents an adjustment coefficient according to whether the influence of the ambient temperature on the calculation of the actual TKPH is to be reduced or increased. The value of the coefficient m is beneficially comprised between 60 and 90; good results are obtained for a value of the coefficient m equal to 75.

[0029] The value of the coefficient R1 for a running cycle, may also be obtained via a second experimental law dependent on the values observed during this cycle, on the unladen running time (t'), on the unladen stoppage time (t'), on the laden running time (t2), on the laden stoppage time t , and on the value of the integration duration (D).

[0030] The second experimental law is of the type: t + tr + tl + t2 ] t+ + t

3012*t _ t t2*t 2*t _ t2] 2 2 DI *+DI DIDI W J DI*D *tr ___~~~~2 I DI *n * *7 + 2n 2e * & 2eDI (2) 1-e1

In which the coefficient n is an adjustment coefficient making it possible to reduce or increase the influence of the stoppage time on the calculation of the actual TK. This coefficient n is beneficially comprised between 0.5 and 0.75; good results are obtained for a value of the coefficient n equal to 0.625.

[0031] The next step C consists finally in calculating the integrated TKPH, TKPH, on the basis of the values of the real TKPH, TKPHR, observed during the n cycles preceding the last cycle considered, and performed during a predetermined integration duration DI.

TKPH = >-o(TTCi x TKPHR,) DI

[0032] Finally, in step D, knowing the value of the integrated TKPH (TKPH) allows this value to be compared with the stabilized maximum TKPH value permissible for the tyre (TKPHMax), in order to adjust the conditions of operation of the vehicle or generate an alert if this is exceeded.

[0033] As already been mentioned, these adjustments to the operating conditions may be made by the driver of the vehicle or at a remote centre of operations.

[0034] It is also possible to determine with a good level of precision the actual temperature OS in the crown of the tyre, by making use of a linear-interpolation law of the type: 0 OS= Amb+ TKPHI X AmM)

TKPHMax(Max - Ab) (5)

Where OS is the maximum permissible crown temperature and is determined by the manufacturer during the tyre design phase, as are the stabilized maximum TKPH values permissible for the tyre (TKPHax).

[0035] The choice of integration duration DIis of particular importance to the reliability and precision of the information supplied by implementing embodiments of the invention.

[0036] Specifically, too long an integration duration increases the risks of anomalies not being detected and lengthens the start-up period by delaying the moment beyond which the operator begins to obtain stable information. Too short an integration duration increases the risks of false detections of anomalies.

[0037] In practice, the integration duration is generally comprised between 5 hours and 15 hours.

[0038] When cycle times are short and regular, it may prove easier to consider the integration duration to be equal to the sum of the cycle times of the n cycles performed in a given duration preceding the cycle considered: DI = E(

[0039] In order not to lose precision in evaluating the TKPH, it is then appropriate for the number of cycles taken into consideration to be relatively high, and preferably greater than fifteen cycles or so, so that, on average, this integration time DI remains relatively constant.

[0040] Nevertheless, the approach that is the most productive and that makes it possible to obtain the best precision in the calculation of the integrated TKPH is to base the determination of the value of this integration duration on the value of a coefficient T

representative of the thermal operation of the tyre, such as its rise in temperature or its cooling.

[0041] Figure 2 illustrates a curve of the rise in temperature of a tyre, which curve is obtained under standardized running conditions for determining the value of the maximum TKPH not to be exceeded, TKPHm, and is supplied by the manufacturer. This standardized running is performed at an outside temperature equal to 380C, for a load equal to 0.8 times the nominal load of the tyre, and for a speed corresponding to the maximum speed at which it is possible to run without exceeding a maximum temperature in the crown of the tyre, and which is defined during the design of this tyre.

[0042] When this curve is being established, the temperature es is measured in the crown of the tyre at the point that is most sensitive to changes in temperature.

[0043] The curve of Figure 2 represents the ratio Os, /6ssab of the maximum temperature observed in the crown of the tyre at an instant t to the maximum temperature observed in the crown of the tyre when the temperature stabilizes. During stabilized running, when the thermal conditions are no longer changing, the ratio is equal to 1.

[0044] It is then possible to determine an experimental curve of the type:

Os t = (Osstab- 38)X ( - et) +38 (6)

[0045] Where t represents the time, and T the said value representative of the temperature rise time of the tyre.

[0046] This value of T evolves as a function of the type of build of the crown of the tyre, and in particular as a function of the thickness of the tread. For civil engineering tyres fitted to dumpers, this time is generally comprised between 3 hours and 6 hours.

[0047] This time T may be communicated by the manufacturer, when the latter has undertaken the series of experiments beforehand. It may also be the subject of an evaluation based on a comparison of the tyre considered against similar tyres for which the value of T is known.

[0048] In the preferred embodiment of the invention, a value chosen for the integration duration DI will be equal to an integer multiple k of this time T : DI = k * T. The coefficient k is beneficially comprised between 1 and 3, and preferably equal to 2. The value of the integration duration is then equal to twice the value of the time T, DI= 2* T.

[0049] It will be seen here that, when the value of the integration duration is equal to a value equal or close to twice the value representative of the temperature-rise time T of the tyre, the value of the correction coefficient R1 is then more precise and makes it possible to obtain a value for the actual TKPH of the observed cycle, TKPHR, that is as close as possible to the observed experimental values.

[0050] Additional precision may also be afforded to the model when the integration duration DI does not correspond to the cumulative time of an integer number of cycles.

[0051] As illustrated in Figure 3, during step C, it is beneficially possible to determine an additional time dt calculated so that the sum of the cycle times taken into consideration, increased by the additional time dt, is equal to the integration duration:

DI = >7_O(TTCj) + dt.

[0052] The calculation of the value of the integrated TKPH (TKPH) is then modified. The sum of the products of the cycle times multiplied by the actual TKPH values (O(TTCi x TKPH) TKPH) is then increased by the value of the product of the actual TKPH (TKPHRI) of the earliest cycle (io) over the integration duration (DI) considered multiplied by the additional time (dt)

TKPHJ= _ 1 (TTCi x TKPHR,) + dt x TKPHRio DI

[0053] This modified calculation that makes it possible to take partially into account the value of the integrated TKPH obtained for the first cycle (io) of the series, performed during the integration duration DI, and to keep an integration duration that remains constant in value throughout all the calculations performed.

[0054] Some embodiments of the invention also provide special arrangements for transient phases such as stoppages.

[0055] A first kind of stoppage, which are stoppages said to be of long-duration, during which the tyre is considered to experience a return of its temperature to a temperature close to the ambient temperature are singled out.

[0056] The second kind of stoppage relates to stoppages said to be of short-duration, the which are distinct from the loading or unloading stoppages performed during the work cycle (t1, t ), and which are characterized by a stoppage time comprised between two time limits, between which the tyre does not have time to cool completely.

[0057] The long-duration stoppages are the stoppages the duration of which exceeds a first time limit Tam.

[0058] When the vehicle is started, the integrated TKPH (TKPH) is determined on the basis of the (i) cycles performed, counted from the restarting of the vehicle, for a duration equal to the integration duration (DI), using the following formula: >Z-o(TTCk x TKPHRk) TKPHI(i) = DI

[0059] This has the effect of taking into account, during the integration duration, the time needed for the tyre to reach a stable temperature. The integrated TKPH values obtained during the first few cycles are therefore diminished in importance until the cumulative time of the cycles performed since starting of the vehicle exceeds the integration duration.

[0060] As a preference, a first time limit Tlu, chosen will be equal to the value of the integration duration multiplied by a coefficient p, beneficially comprised between 2 and 5 (T1 1i2= p*DI); good results are obtained for a value of p=5/ 2

.

[0061] It will be seen here that this value is equal to 5*T, when DI=2*. This value corresponds to the cooling times observed for outside temperatures of the order of 380C.

[0062] When the cumulative time of the cycles performed since the starting of the vehicle is greater than the integration duration DI, the calculation of the integrated TKPH is repeated in accordance with the process described for step C.

[0063] The short-duration stoppages are the stoppages the duration of which is interrupted between the first time limit Tlu, and the second time limit T2,i less than the first time limit Tin,.

[0064] Byway of example, the second time limit T2,i ,may beneficially be equal to one hour.

[0065] At the end of the stoppage time, upon the restarting of the vehicle, a TKPH value ((TKPH(A)) is determined as a function of the integrated TKPH obtained during the last cycle preceding the stop (TKPH(to)), of the duration of the stop (t-to), and of the value of the integration duration DI, using a third experimental law of the type: 2 (t i -to) TKPH(A)= TKPH(to) x e qDI (3) in which the coefficient q is an adjustment coefficient comprised between 2 and 5 depending on the more or less prudent weighting that is to be given to the value of (TKPH(A)). This coefficient q is beneficially comprised between 2 and 5; and good results are obtained for a value of q equal to 3.

[0066] Once the vehicle has restarted, and for a duration equal to the integration duration (DI), the integrated TKPH, (TKPH(i)), is determined on the basis of the (i) cycles performed, counted from the restarting of the vehicle, as a function of the integrated TKPH (TKPH(A)) determined at the moment of the end of the stoppage time of the vehicle, of the integration duration (DI), and of the stoppage time (t-to) , using a fourth experimental law of the type:

TKPH1(i) = Y=0(TTCDTKPHkDI+ TKPH(A) x (1 - DI ) (4)

[0067] When the cumulative time of the cycles performed since the restarting of the vehicle is greater than the integration duration DI, the calculation of the integrated TKPH is repeated in accordance with the process described step C.

[0068] It goes without saying that the said experimental laws (1, 2, 3, 4, 5, 6) proposed above needs to be understood to mean laws derived from observing thermal phenomena and changes therein. Also, it is possible to obtain substantially equivalent results using experimental laws that call upon distinct mathematical formulations producing similar results.

[0069] An aspect of the invention finally relates to the device for implementing the method as described hereinabove.

[0070] This device comprises: - means 20 for exchanging data with sensors 31, 32 able to acquire values for temperature (eami),for cycle time or cycle duration (tl, t1, t2, t,,to),forload(QQ2) and for distance (L,, L2 ), - at least one computer processing unit 20, and - coded instructions allowing the steps of the method according to the invention and which are described hereinabove to be executed.

[0071] Another aspect of the invention finally comprises software containing programmed code elements for running the method that forms the subject of the present description when the said software is loaded into a computer processing unit and executed by the said processing unit 20, as well as the said software, in the form of a product recorded on a medium readable by a computer processing unit, containing the said programmed code elements.

[0072] In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

[0073] It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

NOMENCLATURE (the units are given by way of example and do not limit the scope of the invention)

1 Site vehicle 2 Housing exchanging data with the sensors positioned on the vehicle 3 Computer processing unit Li Distance covered unladen (km) L2 Distance covered laden (km) Q1 Load borne by the tyre when unladen (t) Q2 Load borne by the tyre when laden (t) TTC Total cycle time (h) TKPHB Baseline TKPH (t.km/h) TKPHR Actual on-site TKPH (t.km/h) TKPH Integrated TKPH (t.km/h) TKPHma Stabilized maximum TKPH communicated by the manufacturer (t.km/h) TKPH(A) TKPH at the moment of the end of the vehicle stoppage time (t.km/h) TKPH1 (to)) Integrated TKPH at the moment of stoppage of the vehicle DI Integration duration (h) dt Additional time (h) 0am1 Ambient temperature (°C) es,tMaximum temperature observed in the crown of the tyre at an instant t '(°C) essro The maximum stabilized temperature observed in the crown of the tyre (°C) tlr Unladen running time (h) t' Unladen stoppage time (h) t ~r Laden running time (h) t ~a Laden stoppage time (h) T1am First time limit (h) T21m Second time limit (h) (t-to) Duration of a short-duration stoppage time (h) k Integer multiplying coefficient T Value representative of the tyre temperature-increased time (h) m, n, p, q Adjustment coefficients

Claims

1. Method for determining a Tonne Kilometre Per Hour (TKPH) index for a tyre fitted to a vehicle effecting a plurality of running cycles laden and unladen, and in which the following steps are performed: - Step A : acquiring, for each cycle, the data relating to the distance covered unladen (Li), the distance covered laden (L2), the load borne unladen (Q1), and laden (Q2), and the total cycle time (TTC), and determining a value for the baseline TKPH (TKPHB):

TKPHB - QTXL+Q 2 xL 2 TTC

- Step B: determining a value for the actual TKPH (TKPH) by multiplying the baseline product TKPH (TKPHB) by corrective coefficients (K2, R1), (TKPHR = TKPHB x K2 x R1),

- Step C : determining an integrated TKPH value (TKPHI) by calculating a moving average, weighted over the plurality (n) of cycles performed during an earlier duration equal to a given integration duration (DI), of the actual TKPH values calculated for each of these cycles: TKPH = >Z=O(TTCi x TKPHR,) DI - Step D : comparing the value of the integrated TKPH (TKPH) with a stabilized maximum TKPH value permissible for the tyre (TKPHax), in order to adjust the conditions of operation of the vehicle or generate an alert if this is exceeded.

2. Method according to Claim 1, in which, in step C, - an additional time (dt) such that the sum of the cycle times, increased by the additional time, is equal to the integration duration (DI = _O(TTCn)+dt)) is determined, and then, - in order to calculate the value of the integrated TKPH, (TKPH), the sum of the products of the cycle times multiplied by the actual TKPH values( (TTC x

TKPHR,)) is increased by the value of the product of the actual TKPH (TKPHO) of the earliest cycle (io) over the integration duration (DI) considered multiplied by the additional time (dt) :

TKPHJ= _1 (TTCi x TKPHR,) + dt x TKPHRio DI

3. Method according to either one of the preceding claims, in which, in step B, the coefficient K2 is given by a first experimental law dependent on the ambient temperature of the outside air(ami)around the truck during a running cycle.

4. Method according to Claim 3, in which the first experimental law (1) is of the type: K2 = 9 m-3) m

in which the value of the coefficient m is comprised between 60 and 90.

5. Method according to any one of the preceding claims, in which, in step B, the coefficient R1 is given, for a given running cycle, by a second experimental law dependent on the values observed during this cycle, on the unladen running time (t'), on the unladen stoppage time (t'), on the laden running time (t2), on the laden stoppage time t , and on the value of the integration duration (D).

6. Method according to Claim 5, in which the second experimental law (2) is of the type:

R,

[t~± + + ~ 2 E1-DI ]1 r=n* *L *# 2A t2l *eii DI

[ DI 2*t'2 t21]

[1 -e DI]* +2*n*

1-e DI+DI DI D 1-elDI DI DI D

in which the value of the coefficient n is comprised between 0.5 and 0.75.

7. Method according to any one of the preceding claims, in which, in step C, upon starting of the vehicle, and after a stoppage time greater than a first predeterminedlimit (T ,2), the integrated TKPH, (TKPHJ), is determined for a duration equal to the integration duration (DI), on the basis of the (i) cycles performed, counted from the restarting of the vehicle, using the following law: >Z-O(TTCk x TKPHRk) TKPHI(i) = DI

8. Method according to Claim 7, in which the value of the first time limit (T2) is equal to the value of the integration duration (DI) multiplied by a coefficient p (Ti=p*DI), and where the value of the coefficient p is comprised between 2 and 5.

9. Method according to Claim 7 or Claim 8, in which, when the vehicle is stopped for duration greater than a second predetermined limit (T2,i2) and less than the first predetermined limit (TIi) , the TKPH at the end of the stoppage time ((TKPH(A)) is determined as a function of the integrated TKPH calculated for the last cycle before the stoppage (TKPHI(to)), of the duration of the stoppage (t-to) and of the value of the integration duration DI, using a third experimental law (3) of the type: 2(ti-to)

TKPH(A)= TKPH1(to) x e q*DI

in which the value of the coefficient q is comprised between 2 and 5.

10. Method according to Claim 9, in which, when the vehicle restarts, the integrated TKPH, (TKPHj(i)), for a duration equal to the integration duration (DI), is determined on the basis of the (i) cycles performed, counted from the restarting of the vehicle, as a function of the integrated TKPH ((TKPH (A)) 1 determined at the moment of the end of the stoppage time of the vehicle, of the integration duration (DI), and of the stoppage time (t-to) , using a fourth experimental law (4) of the type: Z'=,(TTCk x TKPHIk) 10 TKPH 1(i)= ( DI + TKPH1(A) x (1 - tI DI

11. Method according to any one of Claims 1 to 10, in which the integration duration (DI) corresponds to a multiple (k), comprised between 1 and 3, of a time (T) representative of the tyre temperature-rise time (DI = k* T).

12. Method according to Claim 11, in which the integration duration (DI) is equal to twice the value (T) representative of the tyre temperature-rise time (DI= 2*T).

13. Method according to any one of Claims 1 to 10, in which the integration duration (DI) is equal to the sum of the cycle times observed during the said integration duration (DI= yi=o(TTCi)).

14. Method according to any one of the preceding claims, in which the tyre is mounted on a civil engineering equipment and in which the integration duration (DI) is comprised between 5 hours and 15 hours.

15. Device for implementing the method according to one of Claims 1 to 14, comprising: - means for exchanging data with sensors able to acquire values for temperature (eami),for cycle time or cycle duration (t, t1, t2, t 2, ti, to), for load (Q,, Q2) and for distance (L,, L 2 ), that are to be processed, - at least one computer processing unit, and - coded instructions allowing the steps of the method to be executed.

16. Software containing programmed code elements for running the method according to any one of Claims 1 to 14 when the said software is loaded into a computer processing unit and executed by the said processing unit.

17. Software in the form of a product recorded on a medium readable by a computer processing unit, containing the said programmed code elements according to Claim 16.