Method and device for assessing a braking temperature, method and computer program product for assessing a braking coefficient

Abstract

A method for evaluating a brake temperature (T brk ) of a brake disc (10) of a vehicle, comprising the steps of virtually separating the brake disc (10) into a brake disc body (11) and a brake disc contact surface layer (12), and evaluating a temperature (T disc ) of the brake disc contact surface layer (12) from a temperature (T cont ) of the brake disc body (11) and an amount of heat input into the brake disc contact surface layer (12) due to a braking action, wherein the evaluated temperature (T cont ) of the brake disc contact surface layer (12) corresponds to the brake temperature (T brk ).

Description

Technical Field

[0001] This invention relates to a method for evaluating the braking temperature of a vehicle's brake disc, a method for evaluating the braking coefficient of a vehicle's disc brake, an apparatus for evaluating the braking temperature of a vehicle's brake disc, and a corresponding computer program product. Background Technology

[0002] The braking coefficient, which is the braking action that converts braking pressure into braking torque acting on the wheels, depends on the temperature of the brake. Therefore, the temperature of the brake can be measured using a suitable temperature sensor. However, such temperature sensors for brakes are expensive due to limited installation space, rotating parts, the high temperatures generated, and requirements regarding contaminants. The aforementioned problems with measuring brake temperature are exacerbated because the relevant brake temperature is obtained within the contact area between the brake disc and brake pads. Summary of the Invention

[0003] Therefore, one object of the present invention is to provide a method and apparatus for evaluating the braking temperature of a vehicle's brake disc, thereby enabling the evaluation of the braking coefficient in a simple manner.

[0004] This objective is achieved by a method for evaluating the braking temperature of a vehicle's brake disc according to claim 1, a method for evaluating the braking coefficient of a vehicle's disc brake according to claim 16, an apparatus for evaluating the braking temperature of a vehicle's brake disc according to claim 17, and a computer program product according to claim 18. Other aspects of the invention are the subject of the appended claims.

[0005] According to the present invention, the method for evaluating the braking temperature of a vehicle's brake disc includes the following steps:

[0006] Virtually separating the brake disc into the brake disc body and the brake disc contact surface layer; and

[0007] The temperature of the brake disc contact surface layer is evaluated based on the temperature of the brake disc body and the heat input generated in the brake disc contact surface layer due to braking action.

[0008] The evaluation temperature of the brake disc contact surface layer corresponds to the braking temperature.

[0009] Therefore, this invention provides a model-based method for assessing brake temperature. The brake disc as a whole exhibits relatively slow temperature dynamics, while the surface in contact with the brake pads has higher temperature dynamics. Therefore, this invention virtually divides the brake disc into a brake disc body and a brake disc contact surface layer. Considering that the brake disc contact surface layer of the brake disc body is relatively thin and of lower mass, the brake disc body can be assumed to be the entire brake disc for ease of calculation. The resulting limitations may be acceptable considering the accuracy required for different applications of the model results. However, for high accuracy, the brake disc body can be further specified, i.e., at least one brake disc contact surface layer can be explicitly subtracted. The temperature of the brake disc contact surface layer can now be assessed based on the temperature of the brake disc body and the heat input to the brake disc contact surface layer on the opposite side of the brake disc body due to braking action; the temperatures of the brake disc body and the brake disc contact surface layer can influence each other due to heat exchange. In other words, when the vehicle decelerates or travels downhill, the brake disc contact surface layer is sandwiched between the brake pads and the brake disc body. In such events, i.e., events related to any temperature dynamics, the brake disc body acts as a radiator.

[0010] The temperature of the brake disc contact surface layer, evaluated using the method described above, corresponds to the braking temperature, which is the temperature used to determine the braking coefficient. The term "corresponds" allows the braking temperature to be set to the temperature of the brake disc contact surface layer and / or adjusted, for example, based on a predetermined algorithm and / or coefficient adjustment. For instance, the braking temperature can be evaluated by multiplying the brake disc contact surface temperature by a correction factor based on empirical data. This correction factor can also vary depending on the temperature of the brake disc contact surface layer.

[0011] Due to the methods described above, brake temperature assessment can replace or supplement the use of expensive sensor technology. Brake temperature assessment can provide reliable temperature results, reduce complexity, and is therefore suitable for serial control devices.

[0012] In some embodiments, the temperature of the brake disc contact surface layer is evaluated by iteratively applying the following thermal balance equation:

[0013]

[0014] Where, m cont c is the mass of the contact surface layer of the brake disc, in kg. cont It is the heat capacity of the contact surface layer of the brake disc, in units of [J / (kgK)]. It is the temperature change of the contact surface layer of the brake disc, in [°C / s]; It is the heat input into the contact surface layer of the brake disc due to the braking action, and the unit is [J / s]; It is the heat loss generated by thermal radiation on the contact surface layer of the brake disc, in units of [J / s]; It is the heat loss generated by convection on the contact surface layer of the brake disc, expressed in [J / s]. It is the heat loss generated by conduction in the contact surface layer of the brake disc, in units of [J / s].

[0015] The thermal balance equation is based on the virtual separation of the brake disc contact surface layer from the brake disc body, and the corresponding heat input and heat loss, to balance changes in thermal energy. For a brake disc made of a single material, c cont equals c disc c disc This refers to the heat capacity of the brake disc, measured in J / (kgK). However, for coated brake discs or other materials, c... cont It may deviate from c disc .

[0016] Different parameters of the thermal balance equation for the temperature of the brake disc contact surface layer can be determined physically. For example, this determination can be based on measurement data and / or data sheets of the sensed brake disc.

[0017] Preferably, It can be calculated as:

[0018]

[0019] Where γ is the transition coefficient from the brake pad to the brake disc contact surface layer, P brk It is braking power.

[0020] The input heat is caused by the braking action, specifically due to the frictional contact between the brake pads and the brake disc contact surfaces. Therefore, the input heat can be determined based on the braking power P. brk Calculation. This is equivalent to... in, Due to braking power P brk The heat input into the brake pads.

[0021] The transition coefficient γ from the brake pad to the brake disc contact surface layer can be determined based on the thermal conductivity λ of the brake disc. disc and the thermal conductivity λ of the brake pad pad (Unit: [W / (m*K)]) and the temperature conductivity (also known as thermal diffusivity) of the brake disc, k disc and the temperature conductivity k of the brake pad pad (Unit is [m]) 2 The calculation is performed using the interim value of the thermal activity coefficient ∈ / s]), and the intermediate value of the thermal activity coefficient ∈ is used:

[0022]

[0023]

[0024] The thermal conductivity k can be calculated as:

[0025]

[0026] Where λ is thermal conductivity, with units of [W / (m*K)]; ρ is density, with units of [kg / m³]. 3 ]; c is the heat capacity.

[0027] In some embodiments, the braking power P brk It can be calculated as:

[0028]

[0029] Among them, dE kin / dt represents the change in kinetic energy; dE pot / dt represents the change in potential energy; m dyn It is the dynamic wheel load per axle; a veh g is the vehicle's acceleration; g is the acceleration due to gravity. It is a change in altitude.

[0030] Therefore, braking power P brk It's calculated based on the vehicle's energy. According to the energy method described above, for example, if the vehicle is going downhill, a change in altitude will occur. When considering the change in potential energy, the change in potential energy should be taken into account.

[0031] Alternative or additional braking power P brk It can be calculated as follows:

[0032]

[0033] Among them, F brk It is the braking force; Δv is the relative lateral (slipping) velocity between the brake pads and the brake disc; M brk It is braking torque; r dyn It refers to the dynamic wheel radius.

[0034] Based on braking torque M brk Calculate braking power P brk Based on the braking torque M brk A relatively precise understanding of this may not be possible, as the braking coefficient varies depending on temperature and other factors. Therefore, a more generally applicable method for calculating braking torque is the method described above, where braking power P is calculated. brk It is a function of energy change, in which variables are widely measured. However, this method does not consider braking torque M. brkThe method is not as detailed as it is because factors affecting braking distribution between wheels are not included.

[0035] In some embodiments, It can be calculated as follows:

[0036]

[0037] Where e is the radioactivity e∈[0,1]; δ is the Stefan-Boltzmann constant, constant δ=5.67*10 -8 W / (m 2 K 4 A cont It is the contact area of ​​the brake disc contact surface layer [m 2 ]; T env It refers to the ambient temperature.

[0038] In some embodiments, It can be calculated as follows:

[0039]

[0040] Among them, h cont It is the heat transfer coefficient of the brake disc contact surface layer, with units of [W / (m²)]. 2 K).

[0041] In some embodiments, It can be calculated as follows:

[0042]

[0043] Where λ is the thermal conductivity of the brake disc contact surface layer, with units of [W / (mK)]; d cont It is the thickness of the contact surface layer of the brake disc, in meters (m).

[0044] Advantageously, any of the above equations and / or T cont,n The initial conditions are predetermined, T cont,n+1 Calculated as It can also be calculated from the initial temperature of the brake disc and the contact surface layer.

[0045] For example, as the initial condition for all temperatures, T cont,0 And T disc,0 We can assume that the temperature is equal to the ambient temperature before the actuation. Therefore, the temperature T cont,n+1 It can be evaluated based on initial conditions. Generally, the temperature T of the brake disc contact surface layer... cont,n+1 Based on the previous temperature T cont,n and corresponding temperature changes The deviation between this theoretical assessment and the actual temperature can be reduced by choosing a small Δt value. However, the smaller the Δt value, the more computation and data transfer is required. Therefore, Δt can be chosen to obtain appropriate results within a limited computational load.

[0046] For the required temperature T of the brake disc body disc The calculation of T disc It can be detected by sensors.

[0047] Due to the temperature T of the brake disc body disc This is the inertial temperature of the entire brake disc; the sensor does not need to be positioned to measure the temperature of the contact surface between the brake disc and the brake pads. Instead, such a sensor can be arranged to detect the temperature T of the disc body based on the side of the brake disc body opposite to and / or the side moving laterally from there to the contact surface between the brake disc and the brake pads. disc The temperature T of the disk disc It can be equal to the detected temperature, or determined in other ways based on the detected temperature, such as by determining it as the average temperature over a predetermined time period or by multiplying the detected temperature by a predetermined coefficient.

[0048] Alternatively or additionally, the temperature T of the brake disc body disc The following heat balance equations can be used for evaluation through iterative application:

[0049]

[0050] Where, m disc c is the mass of the brake disc body, in [kg]; disc This is the heat capacity of the brake disc, expressed in [J / (kgK)]. This refers to the temperature change of the brake disc body, expressed in [°C / s]. It is the heat input generated in the brake disc body due to conduction of the contact surface layer of the brake disc, and the unit is [J / s]; It is the heat loss of the brake disc body due to thermal radiation, measured in [J / s]; It is the heat loss of the brake disc body due to convection, measured in [J / s]; It is the heat loss generated by conduction in the contact surface layer of the brake disc, in units of [J / s].

[0051] This temperature T of the brake disc disc The evaluation principle and the temperature T of the brake disc contact surface layer cont The evaluation principle is similar.

[0052] Temperature T of the brake disc disc Evaluation and sensor-based temperature Tdisc The combination of these can not only provide redundancy, but can also be applied to monitoring and / or adjusting the temperature for evaluation.

[0053] In some embodiments, It can be calculated as:

[0054]

[0055] Among them, A disc,out It is the external area of ​​the brake disc, measured in meters. 2 ].

[0056] The external area describes the surface of all areas facing away from the disk and therefore visible from the outside. For example, in a ventilated disk, the area of ​​the ventilation channels is not included. The reason is that, ideally, all radiant heat from the surface of the ventilation channels would directly heat the opposite area of ​​the disk, so this is only internal heat flow and does not change the overall equilibrium of the disk.

[0057] In some embodiments, It can be calculated as follows:

[0058]

[0059] Among them, h disc It is the heat transfer coefficient of the brake disc, with units of [W / (m³)]. 2 K)];A disc,in It is the internal area of ​​the brake disc, measured in meters. 2 ].

[0060] Internal area refers to the area within the ventilation duct.

[0061] In some embodiments, It can be calculated as follows:

[0062]

[0063] Among them, A axle It is the cross-sectional area of ​​the shaft, with units of [m]. 2 ]; T axle It is the temperature of the shaft, measured in [°C]; axle It is the length of the shaft, in meters (m).

[0064] Advantageous is that T disc,n and T cont,n and / or The initial conditions can be determined in advance, T disc,n+1 Calculated as

[0065] It can also be calculated based on the initial temperature of the disk and the contact surface layer.

[0066] Temperature T of the contact surface layer of the brake disc already described cont Similarly, temperature T disc,n+1 An evaluation can be made based on initial conditions. Similarly, the deviation from this theoretical evaluation to the actual temperature can be reduced by choosing a small Δt value. However, the smaller the value of Δt, the more computation and data transfer is required. Therefore, Δt can be chosen to obtain appropriate results within a limited computational load.

[0067] In another aspect, the present invention relates to a method for evaluating the braking coefficient of a vehicle's brake disc, wherein the braking coefficient is based on a braking temperature T evaluated using the method described above. brk It was determined that.

[0068] The braking coefficient can be evaluated based on the braking temperature T. brk It is calculated or selected from the corresponding database.

[0069] Another aspect of the invention relates to a method for evaluating the braking temperature T of a vehicle's brake disc. brk The device includes equipment configured to evaluate the temperature T of the brake disc contact surface layer as described above. cont The control device is configured to convert the temperature of the brake disc contact surface layer into a corresponding braking temperature.

[0070] As already discussed in the method of this invention, the braking temperature T brk The temperature of the brake disc contact surface layer can be converted by means of a temperature set to the brake disc contact surface layer and / or, for example, by adjusting a predetermined algorithm and / or coefficient. For example, the brake temperature T... brk It can be T brk =T cont or T brk =a*T cont Or it can be described using even more complex mathematical methods.

[0071] The present invention also relates to a computer program product comprising instructions that, when executed by a computer, cause the computer to perform actions for evaluating the brake temperature T of a vehicle's brake discs. brk The methods and / or methods for evaluating the braking coefficient of a vehicle's disc brakes are both as described above.

[0072] In summary, this invention is based on the virtual separation of the brake disc into a brake disc body and a brake disc contact surface layer. Vehicle braking torque or acceleration and altitude data, especially considering the distribution of braking force, are used as the braking temperature T of the brake disc. brkThe model's inputs. The corresponding assessment of brake temperature can be achieved through heat balance equations, assuming, for example, the point masses of the brake pads, brake disc contact surface layer, and brake disc body. These heat balance equations can be applied to the temperatures of the brake disc contact surface layer and / or the brake disc body. Heat flux can be distributed according to physical parameters. Attached Figure Description

[0073] Other advantages, aspects, and details of the invention are conferred by the claims, the following description of preferred embodiments applying the principles of the invention, and the accompanying drawings. In particular:

[0074] Figure 1 This is a schematic diagram of an exemplary brake disc and brake pads acting on such a brake disc; and

[0075] Figure 2 It is based on Figure 1 A schematic diagram of the actual separated components of the brake disc and brake pads, and also indicates the corresponding heat input and loss. Detailed Implementation

[0076] Figure 1 The diagram shows the brake disc 10 configured to rotate about the brake disc axis 13, as indicated by the arrow. This is due to the braking pressure p applied by the brake pads 20 to the brake disc 10. brk Brake disc 10 can be decelerated. Although Figure 1 Two brake pads 20 are shown, but the number of brake pads is not limited to this. The entire contact area between the brake pads 20 and the brake disc 10 can be considered as the brake disc contact surface layer 12. Accordingly, the brake disc contact surface layer 12 can also be formed by multiple individual brake disc contact surface layer segments distributed on the brake disc. The thickness of the brake disc contact surface layer 12 perpendicular to the contact area with the brake pads 20 is assumed to be significantly less than the thickness of the remaining brake disc 10, which is assumed to be the brake disc body 11. For example, the brake disc contact surface layer 12 can be assumed to be approximately 10% of the overall thickness.

[0077] To evaluate the braking temperature T of the brake disc 10 in this vehicle braking system brk ,according to Figure 2 The brake disc and interacting components are virtually separated from each other. Furthermore, the corresponding heat input and loss are indicated by indexed arrows.

[0078] The separate brake disc contact surface layer 12, which contacts the individual brake pads 20, varies according to the applied braking power P. brk Receives heat input. Braking power P brk It can be calculated as follows:

[0079]

[0080] Among them, dEkin / dt represents the change in kinetic energy; dE pot / dt represents the change in potential energy; m dyn It is the dynamic wheel load per axle; a veh g is the vehicle's acceleration; g is the acceleration due to gravity. It is a change in altitude. Alternatively or additionally, the braking power P brk It can be calculated as follows:

[0081]

[0082] Among them, F brk It is the braking force; Δv is the relative lateral (slip) velocity between the brake pads and the brake disc; M brk It is braking torque; r dyn It refers to the dynamic wheel radius.

[0083] Meanwhile, the separated brake disc contact surface layer 12 can transfer heat to the brake disc body 12 through conduction, for example:

[0084]

[0085] Where λ is the thermal conductivity of the brake disc contact surface layer, with units of [W / (mK)]; d cont It is the thickness of the contact surface layer of the brake disc, and the unit is [m].

[0086] Other heat losses due to radiation and / or convection can be considered.

[0087] Similarly, due to heat conduction from the brake disc contact surface to the brake disc body 11, the brake disc body 11 receives the pressure... The heat input. However, the brake disc body 11 also presses due to convection. Heat is transferred, and the temperature is adjusted according to radiation. Heat is transferred by conduction. Heat is transferred to shaft 13. In other words, the braking power P brk It is provided as energy input, while energy is discharged due to convection, radiation, and conduction.

[0088] Based on the separate brake disc contact surface layer 12 and brake disc body 11, a model can be established to evaluate the temperature T of the brake disc contact surface layer 12. cont The corresponding braking temperature T brk .

[0089] According to an exemplary embodiment, this model calculates the temperature T of the brake disc 11 based on braking power, preferably taking into account braking force distribution, using braking torque or acceleration and height data. disc Temperature T of the surface layer 12 in contact with the brake disccont .

[0090] According to Figure 2 The virtual separation can be calculated based on the iterative application of the following heat balance equations:

[0091] a) Regarding the temperature T of the brake disc body 11 disc

[0092]

[0093] Where, m disc c is the mass of the brake disc body, in [kg]; disc This is the heat capacity of the brake disc, expressed in [J / (kgK)]. This refers to the temperature change of the brake disc body, expressed in [°C / s]. It is the heat input generated in the brake disc body due to conduction of the contact surface layer of the brake disc, and the unit is [J / s]; It is the heat loss of the brake disc body due to thermal radiation, measured in [J / s]; It is the heat loss of the brake disc body due to convection, measured in [J / s]; It is the heat loss of the brake disc body due to conduction, and the unit is [J / s].

[0094] b) Regarding the temperature T of the brake disc contact surface layer 12 cont

[0095]

[0096] Where, m cont c is the mass of the contact surface layer of the brake disc, in kg. cont It is the heat capacity of the contact surface layer of the brake disc, in units of [J / (kgK)]. It is the temperature change of the contact surface layer of the brake disc, in [°C / s]; It is the heat input into the contact surface layer of the brake disc due to the braking action, and the unit is [J / s]; It is the heat loss generated by thermal radiation on the contact surface layer of the brake disc, in units of [J / s]; It is the heat loss generated by convection on the contact surface layer of the brake disc, expressed in [J / s]. It is the heat loss generated by conduction in the contact surface layer of the brake disc, in units of [J / s].

[0097] The corresponding heat loss can be calculated as follows:

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104] Where e is the radioactivity e∈[0,1]; δ is the Stefan-Boltzmann constant δ=5.67*10 -8 W / (m 2 K 4 A cont It is the contact area of ​​the brake disc contact surface layer, in units of [m²]. 2 ]; T env The ambient temperature; h disc It is the heat transfer coefficient of the brake disc body, with units of [W / (m³)]. 2 K)];A disc,in This refers to the internal area of ​​the brake disc body, in units of [m²]. 2 ];A axle It is the cross-sectional area of ​​the shaft, and the unit is [m]. 2 ]; T axle It is the temperature of the shaft, measured in [°C]; axle It is the length of the shaft, in meters (m); A cont It is the contact area of ​​the brake disc contact surface layer, and the unit is [m²]. 2 ]; h cont It is the heat transfer coefficient of the brake disc contact surface layer, with units of [W / (m²)]. 2 K)];λ is thermal conductivity, with units of [W / (mK)];d cont It is the thickness of the contact surface layer of the brake disc, and the unit is [m].

[0105] As an initial condition, T disc and T cont Assumed to be equal to ambient temperature T amb , It can be calculated from the initial temperature.

[0106] Therefore, the braking temperature can be evaluated by iteratively applying the following thermal balance equation: or Where n is an integer, n∈N0 + .

[0107] The assessed braking temperature T brkThis can be converted into a corresponding braking coefficient for application of control functions.

[0108] The present invention has been described herein in conjunction with various embodiments. However, those skilled in the art, upon studying the accompanying drawings, disclosure, and appended claims, will understand and implement other modifications to the disclosed embodiments when carrying out the claimed invention. Such modifications may involve other features already known in the art that can be used to replace or supplement the features already described herein. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite term "a" or "an" does not exclude a plurality.

[0109] List of reference numerals

[0110] 10 Brake disc

[0111] 11 Brake disc body

[0112] 12 Brake disc contact surface layer

[0113] 13 axes

[0114] 20 Brake pads

[0115] p brk Braking pressure

[0116] P brk Braking power

[0117] Heat loss due to conduction at the brake disc contact surface layer

[0118] Heat loss from the brake disc due to convection

[0119] Heat loss from the brake disc due to conduction

[0120] Heat loss from the brake disc due to radiation

Claims

1. A method for evaluating the braking temperature T of a vehicle's brake disc (10). brk The method includes the following steps: Virtually separating the brake disc (10) into a brake disc body (11) and a brake disc contact surface layer (12); and According to the temperature T of the brake disc body (11) disc The temperature T of the brake disc contact surface layer (12) is evaluated by the heat input due to braking action. cont , The evaluation temperature T of the brake disc contact surface layer (12) is... cont Corresponding to the braking temperature T brk .

2. The method according to claim 1, wherein, The temperature T of the brake disc contact surface layer (12) cont It is evaluated by iteratively applying the following heat balance equation: Where, m cont The mass of the brake disc contact surface layer (12) is expressed in kg; c cont It is the heat capacity of the contact surface layer (12) of the brake disc, in units of [J / (kgK)]; It is the temperature change of the contact surface layer (12) of the brake disc, in units of [℃ / s]; It is the heat input into the contact surface layer (12) of the brake disc due to the braking action, and the unit is [J / s]; It is the heat loss of the contact surface layer (12) of the brake disc due to thermal radiation, in units of [J / s]; It is the heat loss of the brake disc contact surface layer (12) due to convection, in units of [J / s]; It is the heat loss generated by conduction in the contact surface layer (12) of the brake disc, in units of [J / s].

3. The method according to claim 2, wherein, Calculated as: Wherein, γ is the transition coefficient from the brake pad (20) to the brake disc contact surface layer (12); P brk It is braking power.

4. The method according to claim 3, wherein, P brk Calculated as: Among them, dE kin / dt represents the change in potential energy; dE pot / dt represents the change in kinetic energy; m dyn This refers to the dynamic wheel load on each axle; a veh g is the vehicle's acceleration; g is the acceleration due to gravity. It is a change in altitude.

5. The method according to claim 3, wherein, P brk Calculated as: Among them, F brk It is the braking force; Δv is the relative lateral slip velocity between the brake pads and the brake disc; M brk It is braking torque; r dyn It refers to the dynamic wheel radius.

6. The method according to any one of claims 2 to 5, wherein, Calculated as: Where e is the radioactivity e∈[0,1]; It is the Stefan-Boltzmann constant. =5.67 10 -8 W / (m 2 K 4 A cont It is the contact area of ​​the brake disc contact surface layer (12), in units of [m²]. 2 ]; T env The ambient temperature.

7. The method according to any one of claims 2 to 6, wherein, Calculated as: Among them, h cont It is the heat transfer coefficient of the brake disc contact surface layer (12), with units of [W / (m²). 2 K)];A cont It is the contact area of ​​the brake disc contact surface layer (12), in units of [m²]. 2 ]; T env The ambient temperature.

8. The method according to any one of claims 2 to 7, wherein, Calculated as: Wherein, λ is the thermal conductivity of the brake disc contact surface layer (12), in units of [W / (mK)]; d cont It is the thickness of the brake disc contact surface layer (12), in [m]; A cont It is the contact area of ​​the brake disc contact surface layer (12), in units of [m²]. 2 ].

9. The method according to any one of claims 2 to 8, wherein, and / or T cont,n The initial conditions are predetermined, T cont,n+1 Calculated as: .

10. The method according to claim 8 or 9, wherein, T disc Detected by sensors.

11. The method according to any one of claims 8 to 10, wherein, The temperature T of the brake disc body (11) disc It is evaluated by iteratively applying the following heat balance equation: Where, m disc The mass of the brake disc body (11) is expressed in kg; c disc It is the heat capacity of the brake disc body (11), in units of [J / (kgK)]; It is the temperature change of the brake disc body (11), in units of [℃ / s]; It is the heat input generated in the brake disc body (11) due to conduction of the contact surface layer of the brake disc, and the unit is [J / s]; It is the heat loss of the brake disc body (11) due to thermal radiation, in units of [J / s]; It is the heat loss of the brake disc body (11) due to convection, in units of [J / s]; It is the heat loss generated by conduction in the contact surface layer (12) of the brake disc, in units of [J / s].

12. The method according to claim 11, wherein, Calculated as: Among them, A disc,out It is the external area of ​​the brake disc body (11), in units of [m²]. 2 e is the radioactivity e∈[0,1]; It is the Stefan-Boltzmann constant. =5.67 10 -8 W / (m 2 K 4 );T env The ambient temperature.

13. The method according to claim 11 or 12, wherein, Calculated as: Among them, h disc It is the heat transfer coefficient of the brake disc body (11), with units of [W / (m³). 2 K)];A disc,in It is the internal area of ​​the brake disc body (11), in units of [m²]. 2 ]; T env The ambient temperature; A disc,out It is the external area of ​​the brake disc body (11), in units of [m²]. 2 ].

14. The method according to claim 11 or 13, wherein, Calculated as: Among them, A axle It is the cross-sectional area of ​​the shaft, with units of [m]. 2 ]; T axle It is the temperature of the shaft, measured in [°C]; axle λ is the length of the shaft, in meters (m); λ is the thermal conductivity of the brake disc contact surface layer (12), in W / (mK).

15. The method according to any one of claims 11 to 14, wherein, T disc,n and T cont,n and / or The initial conditions are predetermined, T disc,n+1 Calculated as: .

16. A method for evaluating the braking coefficient of a disc brake in a vehicle, wherein, The braking coefficient is the braking temperature T evaluated according to the method described in any one of claims 1 to 15. brk It was determined that.

17. A method for evaluating the braking temperature T of a vehicle's brake disc (10). brk The device includes an instrument configured to evaluate the temperature T of the brake disc contact surface layer (12) by the method according to any one of claims 1 to 15. cont The controller, in which, The controller is configured to measure the temperature T of the brake disc contact surface layer (12). cont Converted to the corresponding braking temperature T brk .

18. A computer program product comprising instructions that, when executed by a computer, cause the computer to perform the method according to any one of claims 1 to 15 and / or 16.

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