Tire temperature estimation method and tire temperature estimation device

Abstract

To provide a tire temperature estimation method and a tire temperature estimation device that can estimate a surface temperature of a tire with good accuracy.SOLUTION: A tire temperature estimation device 100 estimates a surface temperature of a tire 2 of a vehicle 1 by using a processor 10. The processor 10 calculates a heat generation amount of the tire 2 on the basis of longitudinal force and lateral force generated in the tire 2 and a slip velocity of the tire 2, acquires a previous temperature estimation value of the surface temperature, acquires a road surface temperature which is a temperature of a road surface R on which the vehicle 1 travels, acquires any one or both of an ambient temperature and an internal temperature of the tire 2 as an environmental temperature, calculates a first heat radiation amount of the tire on the basis of a temperature difference between the previous temperature estimation value and the road surface temperature, calculates a second heat radiation amount of the tire on the basis of a temperature difference between the previous temperature estimation value and the environmental temperature, then calculates a temperature change amount of the surface temperature on the basis of the heat generation amount, the first heat radiation amount and the second heat radiation amount, and estimates the surface temperature on the basis of the previous temperature estimation value and a temperature change amount.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a tire temperature estimation method and a tire temperature estimation device. [Background technology]

[0002] The tire temperature detection means included in the vehicle control device described in Patent Document 1 calculates the amount of heat dissipated from the tire based on the road surface temperature in order to estimate the tire temperature. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-51837 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the tire temperature detection method of Patent Document 1, the amount of heat dissipation is calculated based only on the road surface temperature, so there are cases in which the tire temperature cannot be estimated with sufficient accuracy.

[0005] An object of the present invention is to provide a tire temperature estimation method and a tire temperature estimation device that can estimate the surface temperature of a tire with high accuracy. [Means for solving the problem]

[0006] The present invention solves the above problem by calculating a first heat dissipation amount of the tire based on the temperature difference between the road surface temperature and the previous temperature estimate of the tire surface temperature, calculating a second heat dissipation amount of the tire based on the temperature difference between the previous temperature estimate and either or both of the outside air temperature and the internal temperature of the tire, and estimating the surface temperature based on the heat generation amount, the first heat dissipation amount, and the second heat dissipation amount. Effect of the Invention

[0007] According to the present invention, the amount of heat dissipation is calculated based on either or both of the outside air temperature and the internal temperature of the tire in addition to the road surface temperature, so that the tire surface temperature can be estimated with high accuracy. [Brief description of the drawings]

[0008] [Figure 1] 1 is a block diagram showing a configuration of a tire temperature estimation device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing a schematic diagram of heat generation and heat dissipation in tires of a vehicle during travel. [Diagram 3] 3A and 3B are diagrams showing the change in vertical load acting on each tire of a vehicle, where FIG. 3A shows the change in vertical load caused by longitudinal acceleration, and FIG. 3B shows the change in vertical load caused by lateral acceleration. [Figure 4] 4 is a flowchart showing the steps of a tire temperature estimation method executed by the tire temperature estimation device shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in Fig. 1, a vehicle 1 has a tire temperature estimation device 100. The tire temperature estimation device 100 estimates the surface temperatures of tires 2 (right front tire 2a, left front tire 2b, right rear tire 2c, and left rear tire 2d) at a predetermined cycle (for example, 10 [msec]). The vehicle 1 also has a steering angle sensor 31, an acceleration sensor 32, a vehicle speed sensor 33, a driving force sensor 34, a road surface temperature sensor 35, an outside air temperature sensor 36, and a TPMS 37 (Tire Pressure Monitoring System). The vehicle 1 also has a driving control device 40 for controlling the driving of the vehicle 1.

[0010] The steering angle sensor 31 detects the steering angle of the tires 2 of the vehicle 1 . The acceleration sensor 32 detects longitudinal acceleration (longitudinal G) and lateral acceleration (lateral G) acting on the vehicle 1. The longitudinal direction is the front-rear direction of the vehicle 1, and the lateral direction is the width direction of the vehicle 1. The vehicle speed sensor 33 detects the speed of the vehicle 1 . The driving force sensor 34 detects the magnitude of the driving force input from a driving source such as an engine or an electric motor.

[0011] The road surface temperature sensor 35 detects the road surface temperature Troad of the road surface R on which the vehicle 1 runs. The road surface temperature sensor 35 is a non-contact temperature sensor attached to the lower part of the body of the vehicle 1. The road surface temperature sensor 35 is disposed at a position facing the road surface R on which the vehicle 1 runs. The outside air temperature sensor 36 is attached to the outside of the vehicle 1 and detects the outside air temperature Tair. The TPMS 37 measures the air pressure of the tires 2 of the vehicle 1 and detects the internal temperature Tinneri of the tires 2 . The means for detecting the road surface temperature Troad, the outside air temperature Tair, and the internal temperature Tinneri of the tire 2 are not limited to the above-mentioned road surface temperature sensor 35, outside air temperature sensor 36, and TPMS 37, and may be other detection devices.

[0012] The driving control device 40 controls the driving of the vehicle 1 based on the surface temperature of the tire 2 estimated by the tire temperature estimation device 100. For example, when the vehicle 1 is an autonomous vehicle with an autonomous driving level of 3 or higher, the driving control device 40 controls the operation of the drive mechanism and the brake operation for adjusting the acceleration / deceleration and the vehicle speed based on the temperature of the tire 2. Also, the driving control device 40 executes steering control of the vehicle 1 by controlling the operation of the steering actuator based on the temperature of the tire 2. Also, when the vehicle 1 is an autonomous driving vehicle with an autonomous driving level of 2 or lower, the driving control device 40 assists the driver in manually driving the vehicle 1 based on the temperature of the tire 2. As a result, even if the characteristics of the tire 2 change depending on the temperature of the tire 2, the driving control device 40 can control the driving of the vehicle 1 so that the behavior of the vehicle 1 is stable.

[0013] The tire temperature estimation device 100 includes a processor 10. The processor 10 includes a ROM (Read Only Memory) in which a program is stored, a CPU (Central Processing Unit) that executes the program stored in the ROM, and a RAM (Random Access Memory) that functions as an accessible storage device. The processor 10 includes a vehicle state acquisition unit 11, a heat generation amount calculation unit 12, a previous temperature estimated value acquisition unit 13, a road surface temperature acquisition unit 14, an environmental temperature acquisition unit 15, a heat dissipation amount calculation unit 16, a temperature change amount calculation unit 17, and a surface temperature estimation unit 18. The processor 10 executes the functions of the vehicle state acquisition unit 11, the heat generation amount calculation unit 12, the previous temperature estimated value acquisition unit 13, the road surface temperature acquisition unit 14, the environmental temperature acquisition unit 15, the heat dissipation amount calculation unit 16, the temperature change amount calculation unit 17, and the surface temperature estimation unit 18 by using the CPU to execute the program stored in the ROM.

[0014] The configuration of the processor 10 will be described in detail below. The vehicle state acquisition unit 11 acquires the steering angle of the vehicle 1 from the steering angle sensor 31. The vehicle state acquisition unit 11 also acquires the longitudinal acceleration (longitudinal G) and lateral acceleration (lateral G) acting on the vehicle 1 from the acceleration sensor 32. The vehicle state acquisition unit 11 also acquires the vehicle speed of the vehicle 1 from the vehicle speed sensor 33. The vehicle state acquisition unit 11 also acquires the magnitude of the driving force from the driving force sensor 34. The vehicle state acquisition unit 11 outputs the steering angle, longitudinal acceleration (longitudinal G), lateral acceleration (lateral G), vehicle speed of the vehicle 1, and the magnitude of the driving force to the heat generation amount calculation unit 12 as vehicle state information.

[0015] The heat generation amount calculation unit 12 calculates the heat generation amount Qg of the tire 2 shown in FIG.

[0016] A specific method for calculating the heat generation amount Qg will be described below. First, the heat generation amount calculation unit 12 calculates the vertical loads Fzfr[N], FzfL[N], Fzrr[N], and FzrL[N] acting on the right front tire 2a, the left front tire 2b, the right rear tire 2c, and the left rear tire 2d, respectively, based on the vertical acceleration (vertical G) and the lateral acceleration (lateral G). Specifically, first, as shown in FIG. 3(a), the vehicle 1 is subjected to a vertical acceleration ax [m / s 2 ], the heat generation amount calculation unit 12 calculates the vertical acceleration ax [m / s 2 The change amount ΔFz [N] of the vertical load Fz [N] caused by the load ΔFz [N] is calculated by the following formula (1), where m [kg] is the mass of the vehicle 1, L [m] is the length of the wheelbase, and hcg [m] is the height of the center of gravity of the vehicle 1.

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[0017] In addition, as shown in FIG. 3(b), vehicle 1 experiences a lateral acceleration ay [m / s 2 ], the calorific value calculation unit 12 calculates the lateral acceleration ay [m / s 2 The amount of change ΔFz [N] in the vertical load Fz [N] caused by the load d [m] is calculated using the following formula (2), where d [m] is the horizontal distance between the left and right wheels of the vehicle 1.

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[0018] Therefore, vehicle 1 experiences a longitudinal acceleration ax [m / s 2 ] and lateral acceleration ay [m / s 2 In the case where vertical loads Fzfr[N], FzfL[N], Fzrr[N], and FzrL[N] acting on the right front tire 2a, the left front tire 2b, the right rear tire 2c, and the left rear tire 2d are calculated by the following formulas (3) to (6). As shown in FIG. 3(a), Lf[m] is the horizontal distance between the front axle and the center of gravity of the vehicle. Furthermore, Lr[m] is the horizontal distance between the rear axle and the center of gravity of the vehicle.

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[0019] The heat generation amount calculation unit 12 also calculates the lateral forces Fyfr[N], Fyfl[N], Fyrr[N], and Fyrl[N] generated in each of the right front tire 2a, the left front tire 2b, the right rear tire 2c, and the left rear tire 2d based on the total lateral force Fytotal[N] of the tire 2 using the following equations (7) to (10). The total lateral force Fytotal of the tire 2 is calculated based on the lateral acceleration ay[m / s 2 ] and the load m [kg] of vehicle 1.

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[0020] The heat generation amount calculation unit 12 calculates each of the longitudinal forces Fxi [N] generated in each of the right front tire 2a, the left front tire 2b, the right rear tire 2c, and the left rear tire 2d by the following formula (11). The total longitudinal force Fxtotal [N] of the tires 2 is calculated based on the driving force of the vehicle 1. Furthermore, FxDestributionRatioi is the driving force distribution ratio of each of the right front tire 2a, the left front tire 2b, the right rear tire 2c, and the left rear tire 2d.

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[0021] Then, the heat generation amount calculation unit 12 refers to the map stored in the database and obtains the longitudinal heat storage coefficient Wx [N·m / °C] for each tire 2 based on the longitudinal forces Fxi [N] and the vertical loads Fzfr [N], Fzfl [N], Fzfr [N], Fzfl [N], and Fzfl [N] generated in each of the right front tire 2a, the left front tire 2b, the right rear tire 2c, and the left rear tire 2d. In addition, the heat generation amount calculation unit 12 refers to a map and obtains the lateral heat storage coefficient Wy [N·m / ℃] for each tire 2 based on the lateral forces Fyfr[N], Fyfl[N], Fyfr[N], Fyfl[N] and vertical loads Fzfr[N], Fzfl[N], Fzfr[N], Fzfl[N] generated in each of the right front tire 2a, left front tire 2b, right rear tire 2c and left rear tire 2d. The map used to acquire the longitudinal heat storage coefficient Wx [N·m / °C] and the lateral heat storage coefficient Wy [N·m / °C] is a map created to reflect the fact that the heat generation amount Qg of the tire 2 becomes saturated when a large load (vertical load, longitudinal force and lateral force generated in the tire 2) equal to or greater than a predetermined value is applied to the tire 2. Therefore, the longitudinal heat storage coefficient Wx [N·m / °C] and the lateral heat storage coefficient Wy [N·m / °C] acquired by the heat generation amount calculation unit 12 are values ​​that take into account the inflection point of the heat generation amount Qg.

[0022] Furthermore, the heat generation amount calculation unit 12 calculates the longitudinal slip speed Vslipxi [m / s] and the lateral slip speed Vslipyi [m / s] based on the steering angle of the vehicle 1 and the vehicle speed of the vehicle 1.

[0023] Then, the heat generation amount calculation unit 12 calculates the heat generation amount Qg based on the longitudinal force Fxi [N] (longitudinal force) which is the longitudinal force generated in the tire 2, the lateral force Fyi [N] which is the lateral force generated in the tire 2, the longitudinal heat storage coefficient Wx [N·m / °C], the lateral heat storage coefficient Wy [N·m / °C], the longitudinal slip speed Vslipxi [m / s], and the lateral slip speed Vslipyi [m / s], using the following equation (12):

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[0024] 1 acquires the previous temperature estimate Ti [°C] of the surface temperature from the surface temperature estimation unit 18. The previous temperature estimate acquisition unit 13 acquires the outside air temperature data read from the CAN as the initial value of the previous temperature estimate Ti [°C].

[0025] In addition, the road surface temperature acquisition unit 14 acquires the road surface temperature Troad [° C.] from the road surface temperature sensor 35.

[0026] Moreover, the environmental temperature acquisition unit 15 acquires the outside air temperature Tair [°C] as the environmental temperature from the outside air temperature sensor 36. The outside air temperature Tair [°C] is the temperature of the atmosphere in the wheel house 1a of the vehicle 1 (see FIG. 2). Furthermore, the environmental temperature acquisition unit 15 acquires the internal temperature Tinneri [°C] of each tire 2 as the environmental temperature from the TPMS 37. Note that the environmental temperature acquisition unit 15 may acquire only either the outside air temperature Tair [°C] or the internal temperature Tinneri [°C] of the tire 2.

[0027] The heat dissipation amount calculation unit 16 includes a first heat dissipation amount calculation unit 16a and a second heat dissipation amount calculation unit 16b. The first heat dissipation amount calculation unit 16a calculates the first heat dissipation amount Qd1 (see FIG. 2), which is the amount of heat dissipated from the tire 2 to the road surface R, by the following formula (13) based on the previous temperature estimation value Ti [°C] and the road surface temperature Troad [°C]. Note that the coefficient k1 [1 / s] may be set to be larger as the road surface temperature Troad [°C] is lower.

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[0028] The second heat dissipation amount calculation unit 16b calculates the second heat dissipation amount Qd2 (see FIG. 2) by the following formula (14) based on the previous temperature estimation value Ti [°C], the outside air temperature Tair [°C], and the internal temperature Tinneri [°C] of the tire 2. The second heat dissipation amount Qd2 includes the heat dissipation amount Qd21 from the surface of the tire 2 to the outside air and the heat dissipation amount Qd22 from the surface of the tire 2 to the inside. That is, the second heat dissipation amount calculation unit 16b calculates the second heat dissipation amount Qd2 based on a value obtained by multiplying the temperature difference between the previous temperature estimation value Ti [°C] and the outside air temperature Tair [°C] by a predetermined heat dissipation coefficient k2 [1 / s], and a value obtained by multiplying the temperature difference between the previous temperature estimation value Ti [°C] and the internal temperature Tinneri [°C] of the tire 2 by a predetermined heat dissipation coefficient k3 [1 / s]. The heat dissipation coefficient k2[1 / s] when the outside air temperature Tair[°C] is a first temperature is larger than the heat dissipation coefficient k2[1 / s] when the outside air temperature Tair[°C] is a second temperature higher than the first temperature. That is, the lower the outside air temperature Tair[°C] is, the larger the heat dissipation coefficient k2[1 / s] is. Similarly to the heat dissipation coefficient k2[1 / s], the heat dissipation coefficient k3[1 / s] may be set to be larger as the internal temperature Tinneri[°C] of the tire 2 is lower.

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[0029] The second heat dissipation amount calculation unit 16b may calculate the second heat dissipation amount Qd2 based only on a value obtained by multiplying a temperature difference between the previous temperature estimation value Ti [°C] and the outside air temperature Tair [°C] by a predetermined heat dissipation coefficient k2 [1 / s]. The second heat dissipation amount calculation unit 16b may calculate the second heat dissipation amount Qd2 based only on a value obtained by multiplying a temperature difference between the previous temperature estimation value Ti [°C] and the internal temperature Tinneri [°C] of the tire 2 by a predetermined heat dissipation coefficient k3 [1 / s].

[0030] Then, the temperature change amount calculation unit 17 calculates the temperature change amount dTi / dt by the following formula (15). That is, the temperature change amount calculation unit 17 calculates the temperature change amount dTi / dt of the surface temperature of the tire 2 based on the heat generation amount Qg, the first heat dissipation amount Qd1(k1(Ti-Troad)), and the second heat dissipation amount Qd2(k2(Ti-Tair)+k3(Ti-Tinneri)). Note that the temperature change amount dTi / dt is the amount of change in the surface temperature of the tire 2 per unit time (for example, 1 second).

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[0031] In other words, the temperature change calculation unit 17 calculates the temperature change dTi / dt by the following equation (16).

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[0032] 1 estimates the surface temperature of each tire 2, i.e., the latest temperature estimated value Ti' [°C], based on the previous temperature estimated value Ti [°C] and the temperature change amount dTi / dt. The surface temperature estimator 18 outputs the estimated value of the surface temperature of the tire 2 (temperature estimated value Ti' [°C]) to the driving control device 40.

[0033] The units of the elements constituting the above formulas (1) to (16) are not limited to those in the above embodiment. In the following description, the units of the elements constituting the above formulas (1) to (16) are omitted.

[0034] Next, the procedure of the tire temperature estimation method executed by the processor 10 of the tire temperature estimation device 100 will be described with reference to the flowchart of FIG. First, in step S1, the heat generation amount calculation unit 12 estimates the forces (longitudinal force Fxi, lateral force Fyi) generated in each tire 2. Note that the longitudinal force Fxi is the longitudinal force generated in each tire 2. Next, in step S2, the heat generation amount calculation unit 12 estimates the vertical loads Fzfr, FzfL, Fzrr, and FzrL of each tire 2. Further next, in step S3, the heat generation amount calculation unit 12 calculates the longitudinal heat storage coefficient Wx and the lateral heat storage coefficient Wy based on the longitudinal force Fxi, the lateral force Fyi and the vertical loads Fzfr, FzfL, Fzrr, and FzrL of each tire 2. Next, in step S4, the heat generation amount calculation section 12 calculates the longitudinal slip speed Vslipxi and the lateral slip speed Vslipyi of each tire 2. The processes of steps S1 to S3 may be executed after the process of step S4, or the processes of steps S1 to S3 and step S4 may be executed simultaneously.

[0035] Then, in step S5, the heat generation amount calculation section 12 calculates the heat generation amount Qg based on the longitudinal force Fxi, the lateral force Fyi, the longitudinal heat storage coefficient Wx, the lateral heat storage coefficient Wy, the longitudinal slip speed Vslipxi, and the lateral slip speed Vslipyi.

[0036] Next, in step S6, the road surface temperature acquisition unit 14 acquires the road surface temperature Troad. Furthermore, in step S7, the environmental temperature acquisition unit 15 acquires the outside air temperature Tair as the environmental temperature. In addition, in step S8, the environmental temperature acquisition unit 15 acquires the internal temperature Tinneri of the tire 2 as the environmental temperature. The processes of steps S6 to S8 may be executed in any order, or may be executed simultaneously. Also, only one of the processes of steps S7 and S8 may be executed.

[0037] Then, in step S9, the heat dissipation amount calculation unit 16 calculates the first heat dissipation amount Qd1 based on the temperature difference between the previous temperature estimate value Ti and the road surface temperature Troad. The heat dissipation amount calculation unit 16 also calculates the second heat dissipation amount Qd2 based on the temperature difference between the previous temperature estimate value Ti and the outside air temperature Tair and the temperature difference between the previous temperature estimate value Ti and the internal temperature Tinneri of the tire 2.

[0038] Then, in step S10, the temperature change amount calculation unit 17 calculates the temperature change amount dTi / dt of the surface temperature of the tire 2 by the following equation (17).

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[0039] Then, next, in step S11, the surface temperature estimating unit 18 estimates the surface temperature of the tire 2 based on the temperature change dTi / dt of the surface temperature of the tire 2. That is, the surface temperature estimating unit 18 calculates the latest temperature estimated value Ti′ of the surface temperature of the tire 2. Then, the process returns to step S1, and the processor 10 repeatedly executes the processes of steps S1 to S11 at a predetermined cycle (for example, 10 [msec]). In addition, the processing of steps S1 to S5 for estimating the heat dissipation amount Qg may be performed after the processing of steps S6 to S9 for estimating the heat dissipation amount (first heat dissipation amount Qd1, second heat dissipation amount Qd2), or the processing of steps S1 to S5 and the processing of steps S6 to S9 may be performed simultaneously.

[0040] As described above, the tire temperature estimation device 100 according to the present embodiment acquires the road surface temperature Troad, and acquires either or both of the outside air temperature Tair and the internal temperature Tinneri of the tire 2 as the environmental temperature. The tire temperature estimation device 100 calculates the first heat dissipation amount Qd1 of the tire 2 based on the temperature difference between the previous temperature estimation value Ti and the road surface temperature Troad, and calculates the second heat dissipation amount Qd2 of the tire 2 based on the temperature difference between the previous temperature estimation value Ti and the environmental temperature. The tire temperature estimation device 100 then calculates the temperature change amount dTi / dt of the surface temperature of the tire 2 based on the heat generation amount Qg, the first heat dissipation amount Qd1, and the second heat dissipation amount Qd2 of the tire 2, and estimates the surface temperature based on the previous temperature estimation value Ti and the temperature change amount. As a result, the tire temperature estimation device 100 calculates the heat dissipation amount based on not only the road surface temperature Troad, but also either or both of the internal temperature Tinneri and the outside air temperature Tair of the tire 2, so that the surface temperature of the tire 2 can be accurately estimated. Furthermore, when acquiring the internal temperature Tinneri of the tire 2 as the environmental temperature, the tire temperature estimation device 100 can accurately estimate the surface temperature of the tire 2 even when heat dissipation from the surface of the tire 2 to the inside is particularly large, such as when the vehicle 1 is performing sports driving under high G or high load conditions. Furthermore, since the tire temperature estimation device 100 can accurately estimate the surface temperature of the tire 2 based on the amount of heat generated and dissipated by the tire 2, there is no need to install a sensor for detecting the surface temperature of the tire 2.

[0041] In addition, the tire temperature estimation device 100 calculates the second heat dissipation amount Qd2 based on a value obtained by multiplying the temperature difference between the previous temperature estimate value Ti and the outside air temperature Tair by a predetermined heat dissipation coefficient k2, and the heat dissipation coefficient k2 when the outside air temperature Tair is a first temperature is larger than the heat dissipation coefficient k2 when the outside air temperature Tair is a second temperature higher than the first temperature. In other words, the lower the outside air temperature Tair, the larger the heat dissipation coefficient k2. This allows the tire temperature estimation device 100 to estimate the surface temperature of the tire 2 based on the tendency that the lower the outside air temperature Tair, the larger the amount of heat dissipation from the surface of the tire 2.

[0042] The tire temperature estimation device 100 also calculates the longitudinal heat storage coefficient Wx based on the vertical load and longitudinal force Fxi acting on the tire 2, and calculates the lateral heat storage coefficient Wy based on the vertical load and lateral force Fyi. The tire temperature estimation device 100 also calculates the longitudinal slip speed Vslipxi and the lateral slip speed Vslipyi. The tire temperature estimation device 100 then calculates the heat generation amount Qg by the following equation (18) based on the longitudinal force Fxi, the lateral force Fyi, the longitudinal heat storage coefficient Wx, the lateral heat storage coefficient Wy, the longitudinal slip speed Vslipxi, and the lateral slip speed Vslipyi.

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[0043] Further, the tire temperature estimation device 100 estimates the temperature change amount dTi / dt based on the heat generation amount Qg, the previous temperature estimate value Ti, the road surface temperature Troad, the outside air temperature Tair, and the internal temperature Tinneri, using the following equation (19).

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[0044] Furthermore, the tire temperature estimation device 100 may calculate the second heat dissipation amount Qd2 based only on the temperature difference between the previous temperature estimate value Ti and the outside air temperature Tair. In this way, the tire temperature estimation device 100 calculates the heat dissipation amount based on not only the road surface temperature Troad but also the outside air temperature Tair, so that the surface temperature of the tire 2 can be estimated with high accuracy.

[0045] Furthermore, the tire temperature estimation device 100 may calculate the second heat dissipation amount Qd2 based only on the temperature difference between the previous temperature estimation value Ti and the internal temperature Tinneri of the tire 2. In this way, the tire temperature estimation device 100 calculates the heat dissipation amount based not only on the road surface temperature Trod but also on the internal temperature Tinneri of the tire 2, and can accurately estimate the surface temperature of the tire 2. Furthermore, the tire temperature estimation device 100 can accurately estimate the surface temperature of the tire 2 even when heat dissipation from the surface to the inside of the tire 2 is particularly large, such as when the vehicle 1 is performing sports driving under conditions of high G or high load. [Explanation of symbols]

[0046] 100...Tire temperature estimation device 1. Vehicle 2. Tires 12...Heat calculation section 13…Previous temperature estimate acquisition section 14...Road surface temperature acquisition section 15…Environmental temperature acquisition section 16a...First heat radiation calculation section 16b...Second heat radiation calculation section 17...Temperature change calculation section 18...Surface temperature estimation section Ti: Previous temperature estimate Troad…Road surface temperature Tair…Outside temperature Tinneri…internal temperature Qg…calorific value Qd1…1st heat dissipation amount Qd2…Second heat radiation amount

Claims

1. 1. A tire temperature estimation method for estimating a surface temperature of a tire of a vehicle using a processor, comprising: The processor, calculating a heat generation amount of the tire based on a longitudinal force and a lateral force generated in the tire and a slip speed of the tire; obtaining a previous temperature estimate of the surface temperature; A road surface temperature, which is the temperature of the road surface on which the vehicle is traveling, is acquired; Acquire either or both of an outside air temperature and an internal temperature of the tire as an environmental temperature; calculating a first heat dissipation amount of the tire based on a temperature difference between the previous temperature estimate value and the road surface temperature; calculating a second heat dissipation amount of the tire based on a temperature difference between the previous temperature estimate value and the environmental temperature; calculating an amount of change in the surface temperature based on the amount of heat generated, the first amount of heat dissipation, and the second amount of heat dissipation; the surface temperature is estimated based on the previous temperature estimate and the amount of temperature change.

2. The processor, calculating the second amount of heat radiation based on a value obtained by multiplying a temperature difference between the previous temperature estimate value and the outside air temperature by a predetermined heat radiation coefficient; The tire temperature estimation method according to claim 1 , wherein the heat dissipation coefficient when the outside air temperature is a first temperature is greater than the heat dissipation coefficient when the outside air temperature is a second temperature higher than the first temperature.

3. The tire temperature estimation method according to claim 1 , wherein the processor calculates the second heat dissipation amount based on a temperature difference between the previous temperature estimate and the outside air temperature.

4. The tire temperature estimation method according to claim 1 , wherein the processor calculates the second heat dissipation amount based on a temperature difference between the previous temperature estimate and the internal temperature.

5. A tire temperature estimation device for estimating a surface temperature of a tire of a vehicle, comprising: a heat generation amount calculation unit that calculates a heat generation amount of the tire based on a longitudinal force and a lateral force generated in the tire and a slip speed of the tire; a previous temperature estimate value acquisition unit that acquires a previous temperature estimate value of the surface temperature; a road surface temperature acquisition unit that acquires a road surface temperature, which is the temperature of a road surface on which the vehicle runs; an environmental temperature acquisition unit that acquires either an outside air temperature or an internal temperature of the tire as an environmental temperature; a first heat dissipation amount calculation unit that calculates a first heat dissipation amount of the tire based on a temperature difference between the road surface temperature and the previous temperature estimation value; a second heat dissipation amount calculation unit that calculates a second heat dissipation amount of the tire based on a temperature difference between the environmental temperature and the previous temperature estimation value; a temperature change amount calculation unit that calculates a temperature change amount of the surface temperature based on the heat generation amount, the first heat dissipation amount, and the second heat dissipation amount; a surface temperature estimating unit that estimates the surface temperature based on the previous temperature estimated value and the amount of temperature change.

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