Tire surface temperature control method and apparatus

Abstract

The present invention provides a tire surface temperature control method and apparatus capable of maintaining the forces that a tire can generate within a favorable range. [Solution] A vehicle equipped with a front and rear wheel load adjustment device that allows adjustment of the load on the front wheels 2FR, 2FL and the rear wheels 2RR, 2RL, and the tire surface temperature T of each wheel 2i i When controlling the tire surface temperature T of each wheel 2i, i The calculated tire surface temperature T i Tire surface temperature T of front and rear wheels 2F, 2R i Temperature difference ΔT FR The first difference between front and back is a predetermined value ΔT FR01 If the above conditions are met, the load on the front and rear wheels is controlled by the front and rear wheel load adjustment device so that the load on the front wheels 2FR and 2FL is increased.

Description

[Technical Field]

[0001] This invention relates to a method and apparatus for controlling tire surface temperature. [Background technology]

[0002] Since the magnitude of the force that can be generated by the tires mounted on the wheels of a vehicle changes depending on the tire surface temperature, Patent Document 1 below discloses a technology for switching the vehicle's motion state control according to the tire surface temperature when controlling the vehicle's motion state. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2012-71678 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, for the force that the tire can generate to be satisfactory, it is desirable that the tire surface temperature be within a predetermined range, but the above-mentioned Patent Document 1 does not control the tire surface temperature. Therefore, there is a possibility that the tire surface temperature may fall outside the range in which the force that the tire can generate to be satisfactory, in which case it may not be possible to obtain the desired vehicle motion state. The present invention aims to provide a tire surface temperature control method and apparatus capable of maintaining the forces that can be generated by a tire within a favorable range. [Means for solving the problem]

[0005] One aspect of the present invention relates to controlling the surface temperature of tires mounted on each wheel of a vehicle equipped with front and rear wheel load adjustment means capable of adjusting the loads of the front and rear wheels. The gist of this invention is to calculate the surface temperature of the tire on each wheel, and if the front-to-rear temperature difference between the front and rear tire surface temperatures of the front and rear wheels is greater than or equal to a first predetermined front-to-rear difference, to control the loads of the front and rear wheels by the front and rear wheel load adjustment means so as to increase the load on the front wheel. [Effects of the Invention]

[0006] According to one aspect of the present invention, the surface temperature of the front tires, which tend to have a higher surface temperature, can be lowered by increasing the load on the front tires, thereby making it possible to maintain the force that the tires can generate within a favorable range. [Brief explanation of the drawing]

[0007] [Figure 1] This is a system configuration diagram showing a tire surface temperature control system, which is one embodiment of the present invention. [Figure 2] Figure 1 shows the configuration of the front and rear wheel load adjustment device and the left and right wheel friction force adjustment device in the vehicle shown. [Figure 3] This is an explanatory diagram of the change in vertical load on each wheel of the vehicle shown in Figure 1. [Figure 4] This is an explanatory diagram of the heat generation and heat dissipation in a wheel tire. [Figure 5] Figure 1 is a flowchart of the calculation process performed in the tire surface temperature calculation unit. [Figure 6] This is an explanatory diagram of the tire temperature dependence model. [Figure 7] This is a control map for the front wheel load increase correction amount in response to the temperature difference between the front and rear wheels. [Figure 8] This is a control map for the correction amount for the increase in inner ring friction force in response to the temperature difference between the left and right sides. [Figure 9] Figure 1 is a flowchart of the calculation process performed in the different tire type detection unit. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below with reference to the drawings. The vehicle 1 of the embodiment shown in Figure 1 has four wheels 2i (i=FR~RL) such as the front right wheel 2FR, front left wheel 2FL, rear right wheel 2RR, and rear left wheel 2RL, similar to a typical passenger vehicle. This vehicle 1 is equipped with a driving control device 31 for automatic driving of the vehicle 1. The vehicle 1 is also equipped with a drive device for driving the vehicle 1. This drive device is equipped with a drive electric motor as a drive source / braking source 12, and the operating state of this drive electric motor is controlled by a braking force controller 12a. By regenerating the drive electric motor, which is the drive source / braking source 12, braking force can be applied to each wheel 2i, so in this embodiment, the braking force of the vehicle 1 can be adjusted by the drive source / braking source 12. Furthermore, this vehicle 1 is equipped with a braking device for braking the vehicle 1 and a steering device for steering the vehicle 1, and also has controllers for controlling each device (neither of which are shown). Vehicle 1 is also equipped with an environmental recognition system for recognizing the surrounding environment, and a communication system for vehicle-to-infrastructure and vehicle-to-vehicle communication, as well as controllers for controlling each of these systems (none of which are shown). The driving control device 31 for autonomous driving of Vehicle 1, for example, based on control inputs such as surrounding environment information obtained from the environmental recognition system and communication information obtained from the communication system, it manages the control state of the controlled objects in the drive system, braking system, and steering system, and outputs control commands to the drive controller, braking controller, and steering controller based on the driving action plan used in current autonomous driving logic of Level 3 or higher. As shown in Figure 4, each wheel 2i is fitted with a tire (pneumatic tire) 3.

[0009] As shown in Figure 2, this vehicle 1 is equipped with front and rear wheel load adjustment devices that adjust the load on each wheel 2i, and left and right wheel friction force adjustment devices that adjust the friction force on each wheel 2i, located at the position of each wheel 2i. In this embodiment, a drive motor, which is a drive source / braking source 12, is connected to the drive shaft 37 of each wheel 2i. As described above, the braking force controller 12a controls the operating state of the drive motor, which is a drive source / braking source 12, to adjust the braking force of the vehicle 1, thereby adjusting the load (wheel load) of the front wheels 2FR, 2FL and the rear wheels 2RR, 2RL. That is, if the driving force of the vehicle 1 is applied or increased, the load of the rear wheels 2RR, 2RL increases, and if the braking force is applied or increased, the load of the front wheels 2FR, 2FL increases. Accordingly, a front and rear wheel load adjustment device is configured that controls the amount of front and rear wheel load adjustment to adjust the load of the front wheels 2FR, 2FL and the rear wheels 2RR, 2RL by controlling the drive source / braking source 12 with the braking force controller 12a. The braking force of the vehicle 1 may be adjusted by operating a hydraulic brake device (not shown) provided on each wheel 2i. In this embodiment, a canard 30, which is a movable wing, is provided at the position of each wheel 2i. This canard 30 is arranged on the vehicle 1 so as to be exposed to the airflow at the position of each wheel 2i, and as shown in Figure 2b, it is provided to be rotatable in a clockwise (counterclockwise) direction in a side view of the vehicle around a rotation axis that extends in the vehicle width direction. The rotation axis of this canard 30 is the output shaft of a canard motor 13, which is composed of an electric motor, and by controlling the rotation state (operating state) of this canard motor 13 with an aerodynamic controller 13a, the resistance of the canard 30 to the airflow changes, which in turn changes the so-called downforce, making it possible to adjust the load and frictional force of each wheel 2i. Here, the aerodynamic controller 13a controls the canard motor 13, which in turn controls the front and rear wheel load adjustment amount to adjust the load on the front wheels 2FR, 2FL and the rear wheels 2RR, 2RL, and the left and right wheel friction force adjustment amount to adjust the friction force on the right wheels 2FR, 2RR and the left wheels 2FL, 2RL. Both the load and friction force on each wheel 2i increase as the downforce from the canard 30 increases.In other words, the canard 30, canard motor 13, and aerodynamic controller 13a constitute a front and rear wheel load adjustment device and a left and right wheel friction force adjustment device, and the canard motor 13 constitutes an aerodynamic adjustment means that adjusts the load of the front and rear wheels 2i aerodynamically. In this example, the canard 30 is positioned above each wheel 2i, but the canard 30 can be positioned anywhere as long as it is possible to adjust the downforce at the position of each wheel 2i. Furthermore, the aerodynamic adjustment means that adjusts the load of the front and rear wheels 2i aerodynamically may include a diffuser or air duct with movable parts.

[0010] Furthermore, in this embodiment, an active suspension, such as the one described in Japanese Patent Application Publication No. 2009-35219, is provided on each wheel 2i. This active suspension is configured by interposing a hydraulic cylinder 33 and a coil spring 34 between a suspension arm (wheel-side member) 32 and a vehicle body (vehicle-side member) 38, and the hydraulic cylinder 33 is arranged so that the cylinder rod extends in the vertical direction. The hydraulic pressure in the pressure chamber of the hydraulic cylinder 33 can be adjusted by a hydraulic control valve 14, thereby allowing adjustment of the height of the vehicle body 38 at the position of each wheel 2i, for example. An accumulator 37 for absorbing unsprung vibrations is connected to the pressure chamber of the hydraulic cylinder 33 via a throttle 36. With the active suspension, for example, by detecting irregularities in the road surface and adjusting the height of the vehicle body 38 at the position of each wheel 2i according to these irregularities, vibrations of the vehicle body 38 can be suppressed to improve ride comfort, and the road-following ability of each wheel 2i can be improved. The hydraulic pressure supplied to the hydraulic cylinder 33 by the hydraulic control valve 14 (operating state) is controlled by the suspension controller 14a. For example, by adjusting the gain of the primary leading component (velocity component) with respect to the displacement of the road surface, the damping force against vertical vibration of each wheel 2i can be adjusted. Specifically, by reducing the gain of the primary leading component with respect to the displacement of the road surface, the damping force can be reduced (improving road surface following ability), and by increasing the gain, the damping force can be increased. Therefore, the smaller the damping force against vibration of the wheel 2i, the better the road surface following ability and the greater the frictional force of the wheel 2i. In addition, with this active suspension, the roll angle of the vehicle body 38 can also be adjusted by adjusting the height of the vehicle body 38 during cornering. During cornering of the vehicle 1, for example as shown in Figure 3b, centrifugal force due to inertia acts on the vehicle body 38, causing the vehicle body 38 to tilt (roll) so that the outside of the vehicle body 38 is lower. In this state, the frictional force of the outer turning wheel is large. If the inclination angle of the vehicle body 38 is defined as the roll angle, the roll angle of the vehicle body 38 can be adjusted by adjusting the height of the vehicle body 38 at the position of each wheel 2i during turning.Here, the frictional force of the turning inner wheel can be increased by adjusting the roll angle so that the roll angle of the vehicle body 38 during turning is reduced, or so that a roll in the opposite direction to the original roll is generated. Accordingly, by adjusting the hydraulic pressure supplied to the hydraulic cylinder 33 by controlling the hydraulic control valve 14 by the suspension controller 14a, the damping force against vibration of each wheel 2i and the roll angle of the vehicle body 38 can be adjusted, thereby controlling the left and right wheel friction force adjustment amount, which adjusts the frictional force of the right wheels 2FR, 2RR and the left wheels 2FL, 2RL in particular. In other words, the active suspension consisting of the hydraulic cylinder 33, hydraulic control valve 14, and suspension controller 14a constitutes the front and rear wheel load adjustment device and the left and right wheel friction force adjustment device. Examples of suspension systems capable of controlling damping force and roll angle include a combination of coil springs, electronically controlled shock absorbers, and active stabilizers.

[0011] Returning to Figure 1, this vehicle 1 is equipped with a tire surface temperature control device 4 that supplies the surface temperature of the tires 3 of each wheel 2i to the aforementioned driving control device 31, and also controls the surface temperature of the tires 3 of each wheel 2i. This tire surface temperature control device 4 is configured as a functional unit comprising a tire surface temperature calculation unit 6 that calculates the surface temperature of each wheel 2i and a tire surface temperature control unit 7. Before explaining the specific configuration and operation of these tire surface temperature calculation unit 6 and tire surface temperature control unit 7, an overview of the tire surface temperature control performed in this embodiment will be described. First, generally, the front wheels 2FR and 2FL, which are steering wheels, have a larger slip angle than the rear wheels 2RR and 2RL, which are driven wheels, so the tire surface temperature of the front wheels 2FR and 2FL tends to be higher than the tire surface temperature of the rear wheels 2RR and 2RL. Also, during cornering, as mentioned above, the vehicle body 38 rolls and the load on the cornering outer wheels increases, so the tire surface temperature of the cornering outer wheels becomes higher than the tire surface temperature of the cornering inner wheels. As shown in Figure 6, in a typical tire, there is a correlation between the tire's maximum friction coefficient and the tire surface temperature, which is called the tire temperature-dependent model. However, if the tire surface temperature becomes too high, the tire's maximum friction coefficient decreases. When the tire's maximum friction coefficient decreases, for example, when the driving control device 31 controls the behavior (motion) state of the vehicle 1, the ideal behavior (motion) state may not be obtained. Therefore, in this embodiment, the tire surface temperature is controlled so that the tire surface temperature of each wheel 2i does not become too high. Specifically, if the temperature difference between the front and rear wheel 2i (front-to-rear temperature difference) exceeds a predetermined value, the load on the front wheels 2FR and 2FL is increased (resulting in increased frictional force) to reduce the tire surface temperature of the front wheels 2FR and 2FL. Also, if the temperature difference between the left and right wheel 2i (left-to-right temperature difference) exceeds a predetermined value, the frictional force of the turning inner wheel is increased to reduce the tire surface temperature of the turning outer wheel. In this embodiment, when increasing the load on the front wheels 2FR and 2FL, aerodynamic adjustment by the canard 30 (aerodynamic adjustment means) and adjustment of the braking force of the drive electric motor, which is the drive source / braking source 12 (braking force adjustment means) can be applied.In this embodiment, when increasing the frictional force of the turning inner wheel, the aerodynamic adjustment by the canard 30 (aerodynamic adjustment means), the damping force adjustment for the vibration of the wheel 2i by the active suspension (damping force adjustment means), and the roll angle adjustment of the vehicle body 38 by the active suspension (roll angle adjustment means) can be applied.

[0012] In this embodiment, since it is intended to perform the control of the tire surface temperature by these adjustments without notifying the vehicle 1 occupants, the load adjustment and the frictional force adjustment of each wheel 2i should be selected or added from those that cause no discomfort or little discomfort. For example, when adjusting the load of the wheel 2i, the front and rear wheel load adjustment by aerodynamic adjustment and the front and rear wheel load adjustment by drive and braking force adjustment are less uncomfortable in that order. Also, when adjusting the frictional force of the wheel 2i, the left and right wheel frictional force adjustment by aerodynamic adjustment, the left and right wheel frictional force adjustment by damping force adjustment, and the left and right wheel frictional force adjustment by roll angle adjustment are less uncomfortable in that order. FIG. 7 is a control map, which graphically shows the front wheel load increase correction amount for the front and rear temperature difference, and FIG. 8 is a control map, which graphically shows the turning inner wheel frictional force increase correction amount for the left and right temperature difference. In FIG. 7, the front and rear temperature difference ΔT FR is greater than or equal to the first front and rear difference predetermined value ΔT FR01 and less than the second front and rear difference predetermined value ΔT FR01 which is larger than the first front and rear difference predetermined value ΔT FR02 in which case the front and rear wheel load adjustment by aerodynamic adjustment is selected, and when the front and rear temperature difference ΔT FR is greater than or equal to the second front and rear difference predetermined value ΔT FR02 and less than the third front and rear difference predetermined value ΔT FR02 which is larger than the second front and rear difference predetermined value ΔT FR03 in which case the front and rear wheel load adjustment by drive and braking force adjustment is additionally selected. The front wheel load increase correction amount (front and rear wheel load adjustment amount) by aerodynamic adjustment and the front wheel load increase correction amount (front and rear wheel load adjustment amount) by drive and braking force adjustment both increase monotonically as the front and rear temperature difference ΔT FR increases, and in this embodiment, it is assumed that those increase correction amounts increase at the same rate with respect to the increase in the front and rear temperature difference ΔT FR . Also, in the region where the front and rear temperature difference ΔT FR is greater than the second front and rear difference predetermined value ΔT FR02 the front wheel load increase correction amount by aerodynamic adjustment is the second front and rear difference predetermined value ΔTFR02 The front wheel load increase correction amount is maintained. Also, the front-to-rear temperature difference ΔT FR The third difference is a predetermined value ΔT FR03 In a larger range, the amount of correction for the increase in front wheel load due to braking and driving force adjustment is the third front-to-rear difference predetermined value ΔT. FR03 The front wheel load increase correction amount is maintained at this value. Here, the second front-to-rear difference predetermined value ΔT FR02 The amount of front wheel load increase correction due to aerodynamic adjustment is set according to the tire specifications so as to suppress the load on the tires. When the load on the front wheels 2FR and 2FL is increased, it is possible to reduce the tire surface temperature of the front wheels 2FR and 2FL up to a certain load as the frictional force increases, but beyond that load, the load increases too much, and there is a risk that the tire surface temperature will actually increase. This "certain load" is determined according to the tire specifications, so the amount of front wheel load increase correction is regulated by this "certain load" according to the tire specifications. In addition, the third front-to-rear difference predetermined value ΔT FR03 The amount of front wheel load increase correction due to brake / drive force adjustment is specified so that the amount of front wheel load increase correction due to brake / drive force adjustment is less than or equal to the amount of front wheel load increase correction that does not cause discomfort to the occupants of vehicle 1.

[0013] Similarly, in Figure 8, the temperature difference ΔT between the left and right sides LR The first left-right difference is a predetermined value ΔT LR01 The above and the first left-right difference predetermined value ΔT LR01 The second left-right difference is a predetermined value ΔT which is larger than this. LR02 If the value is less than ΔT, select aerodynamic adjustment to adjust the left and right wheel friction force, and the left and right temperature difference ΔT LR The second left-right difference is a predetermined value ΔT LR02 The above and the second left-right difference predetermined value ΔT LR02 The third left-right difference is a predetermined value ΔT which is greater than the third left-right difference. LR03 If the value is less than the left / right wheel friction force adjustment by damping force adjustment, select the option to adjust the left / right temperature difference ΔT LR The third left-right difference is a predetermined value ΔT LR03 The above and the third left-right difference predetermined value ΔT LR03 The fourth left-right difference, a predetermined value ΔT, is greater than this. LR04If it is less than [value], select the option to adjust the left and right wheel friction force by adjusting the roll angle. The amount of correction for the increase in cornering inner wheel friction force due to aerodynamic adjustment (left and right wheel friction force adjustment amount), the amount of correction for the increase in cornering inner wheel friction force due to damping force adjustment (left and right wheel friction force adjustment amount), and the amount of correction for the increase in cornering inner wheel friction force due to roll angle adjustment (left and right wheel friction force adjustment amount) are all related to the left and right temperature difference ΔT. LR As the value increases, it increases monotonically, and in this embodiment, the amount of these increasing corrections is the left-right temperature difference ΔT LR It was decided that the increase would be the same rate of increase for an increase in . Also, the temperature difference between the left and right sides ΔT LR The second left-right difference is a predetermined value ΔT LR02 In larger regions, the amount of correction for the increase in inner wheel friction force during cornering due to aerodynamic adjustment is the second left-right difference predetermined value ΔT. LR02 The amount of correction for the increase in the inner ring friction force during turning is maintained. Also, the left-right temperature difference ΔT LR The third left-right difference is a predetermined value ΔT LR03 In larger regions, the correction amount for the increase in inner wheel friction force during cornering due to damping force adjustment is the third left-right difference predetermined value ΔT. LR03 The amount of correction for the increase in the inner ring friction force during turning is maintained. Also, the left-right temperature difference ΔT LR The fourth left-right difference is a predetermined value ΔT LR04 In larger regions, the correction amount for the increase in inner wheel friction force during turning due to roll angle adjustment is the fourth left-right difference predetermined value ΔT. LR04 The amount of correction for the increase in the inner ring friction force during turning is maintained. Here, the second left-right difference predetermined value ΔT LR02 The amount of correction for the increase in inner wheel friction force during cornering due to aerodynamic adjustment is set according to the tire specifications so as described above, in order to suppress the load on the tire. Also, the third front-to-rear difference predetermined value ΔT LR03 The amount of correction for the increase in inner wheel friction force during cornering due to damping force adjustment is specified so that the amount of correction for the increase in inner wheel friction force during cornering due to damping force adjustment is less than or equal to the amount of correction for the increase in inner wheel friction force during cornering that does not cause discomfort to the occupants of vehicle 1. Also, the fourth front-to-rear difference predetermined value ΔT LR04 The amount of correction for the increase in turning inner wheel friction force due to roll angle adjustment is specified so that the amount of correction for the increase in turning inner wheel friction force due to roll angle adjustment is less than or equal to the amount of correction for the increase in turning inner wheel friction force that does not cause discomfort to the occupants of vehicle 1.

[0014] Returning to Figure 1, in order to enable the tire surface temperature control device 4, the vehicle 1 is equipped with a steering angle sensor 21, an acceleration sensor 22, a speed sensor 23, a drive force sensor 24, a road surface temperature sensor 25, an outside air temperature sensor 26, and a TPMS (Tire Pressure Monitoring System) 27. The steering angle sensor 21 detects the steering angle (turning angle) δ of the front wheels 2FR and 2FL, which are the steering wheels of the vehicle 1. The acceleration sensor 22 detects the longitudinal acceleration a generated in the vehicle 1. X and the acceleration a in the width direction (lateral direction) of vehicle 1 Y The speed sensor 23 detects the vehicle's speed V. The drive force sensor 24 detects the drive force and braking force (braking force) F generated in the vehicle 1. XTTL The sensors detect the road surface temperature T of the road surface on which the vehicle 1 is traveling. ROAD It detects the temperature in [°C] and is composed of, for example, a non-contact temperature sensor. The road surface temperature T detected by this road surface temperature sensor 25 ROAD This is acquired by a road surface temperature acquisition unit 18 built within the processor 5, which will be described later. The outside air temperature sensor 26 detects the outside air temperature T outside the vehicle 1. AIR The TPMS (Tire Pressure Monitoring System) detects the temperature in [°C], and in this embodiment, it is installed on a part facing the inside of the wheel well of the vehicle 1 to detect the temperature around the tire 3 of the wheel 2i inside the wheel well. The TPMS 27 detects the air pressure of the tire 3 of each wheel 2i, as well as the internal temperature of the tire 3 (tire internal temperature) T INR It detects the temperature in [°C] and is attached to the wheel of each wheel 2i, for example. The ambient temperature T detected by the ambient temperature sensor 26 AIR and the internal tire temperature T detected by TPMS27 INR This is obtained by the ambient temperature acquisition unit 19 built within the processor 5, which will be described later. Note that the tire internal temperature T INR This is used with the subscript i indicating the position of each wheel 2i.

[0015] The tire surface temperature control device 4 has a processor 5 with advanced arithmetic processing capabilities. The processor 5 includes a ROM (Read Only Memory) where programs are stored, a CPU (Central Processing Unit) that executes the programs stored in the ROM, and RAM (Random Access Memory) that functions as an accessible storage device. The tire surface temperature calculation unit 6, which is provided in the processor 5 as a functional unit, has a vehicle state acquisition unit 17, a heat generation amount calculation unit 8, a previous temperature acquisition unit 20, a road surface temperature acquisition unit 18, an ambient temperature acquisition unit 19, a heat dissipation amount calculation unit 9, a temperature change amount calculation unit 10, and a surface temperature calculation unit 11. The heat dissipation amount calculation unit 9 further has a first heat dissipation amount calculation unit 9a and a second heat dissipation amount calculation unit 9b. The tire surface temperature control unit 7 has a tire temperature difference calculation unit 7a, a front and rear wheel load control unit 7b, and a left and right wheel friction force control unit 7c. These functional units operate when the CPU executes programs stored in the ROM within the processor 5.

[0016] The following describes how the tire surface temperature calculation unit 6 estimates the surface temperature of the tire 3. The vehicle state acquisition unit 17 of the tire surface temperature calculation unit 6 obtains the steering angle (turning angle) δ of the vehicle 1 from the steering angle sensor 21 and the longitudinal acceleration (longitudinal acceleration) a of the vehicle 1 from the acceleration sensor 22. X and the acceleration (lateral acceleration) in the width direction (lateral direction) of vehicle 1 a Y The speed sensor 23 transmits the vehicle's travel speed V, and the drive force sensor 24 transmits the braking force F. XTTL The magnitude of the vehicle is obtained, and this information is output to the heat generation calculation unit 8 as vehicle state information. The heat generation calculation unit 8 calculates the heat generation of the tires 3 of each wheel 2i based on the input vehicle state information. The heat generation is calculated as follows. First, the heat generation calculation unit 8 calculates the vertical acceleration a as shown in Figure 3a. X [m / s 2 Change in vertical load ΔF due to ] Z-X [N] is calculated according to the following formula. In the formula, M[kg] is the mass of vehicle 1, L[m] is the wheelbase (farthest axle distance) of vehicle 1, H CG [m] is the height of the center of gravity of vehicle 1. Similarly, as shown in Figure 3b, the lateral acceleration a Y [m / s2 Change in vertical load ΔF due to ] Z-Y [N] is calculated according to the following two formulas. In the formulas, D[m] is the tread of vehicle 1 (distance between the centers of the contact surfaces of the left and right wheels).

[0017]

number

[0018] Then, using these vertical load changes, the vertical load of each wheel 2i, i.e., the front right wheel load F, is calculated. ZFR [N], front left wheel load F ZFL [N], rear right wheel load F ZRR [N], rear left wheel load F ZRL [N] is calculated according to the following equations 3 to 6. Note that in the equations, L R [m] is the distance between the center of gravity and the rear axle of vehicle 1, L F [m] is the distance between the center of gravity and the front axle of vehicle 1.

[0019]

number

[0020] Furthermore, the heat generation calculation unit 8 calculates the total lateral force F of the vehicle 1 (all wheels 2i). YTTL [N] is distributed to each wheel 2i, and the lateral force of each wheel 2i, i.e., the lateral force F of the front right wheel, is distributed in this manner. YFR [N], Front left wheel lateral force F YFL [N], Rear right wheel lateral force F YRR [N], rear left wheel lateral force F YRL [N] is calculated according to equations 7-10 below. Note that the total lateral force F of vehicle 1 YTTL [N] represents the mass M [kg] of vehicle 1 and the lateral acceleration a Y [m / s 2 It is the product of ].

[0021]

number

[0022] Furthermore, the heat generation calculation unit 8 calculates the braking and driving force F of the vehicle 1 (all wheels 2i).XTTL Distribute [N] to each wheel 2i in such a manner that the vertical force of each wheel 2i, that is, the vertical force of the front right wheel F XFR [N], the vertical force of the front left wheel F XFL [N], the vertical force of the rear right wheel F XRR [N], the vertical force of the rear left wheel F XRL [N] is calculated according to the following equation (11). In the equation, DR is the ratio of the braking and driving force distribution to each wheel 2i, and the subscript i represents the position of the wheel 2i, that is, FR which means the front right, FL which means the front left, RR which means the rear right, and RL which means the rear left.

[0023]

Equation

[0024] Then, the heat generation amount calculation unit 8 refers to a pre-stored map based on the vertical force F Xi [N] of each wheel 2i and the vertical load F Zi [N] to obtain the longitudinal heat storage coefficient (which is also the heat capacity) W Xi [N·m / ℃] of the tire 3 of each wheel 2i. Similarly, the heat generation amount calculation unit 8 refers to a pre-stored map based on the lateral force F Yi [N] of each wheel 2i and the vertical load F Zi [N] to obtain the lateral heat storage coefficient (heat capacity) W Yi [N·m / ℃] of the tire 3 of each wheel 2i. The map used to obtain the longitudinal heat storage coefficient (hereinafter referred to as the tire longitudinal heat storage coefficient) W Xi and the lateral heat storage coefficient (tire lateral heat storage coefficient) W Yi of the tire 3 of each wheel 2i is a map created by reflecting the fact that when a load (vertical load, longitudinal force, and lateral force) greater than a predetermined value is applied to each tire 3, the heat generation amount QG of the tire 3 saturates. Therefore, the tire longitudinal heat storage coefficient W Xi and the tire lateral heat storage coefficient W Yi obtained by the heat generation amount calculation unit 8 increase as the load increases, but the rate of increase gradually becomes smaller, similar to the heat generation amount QG iIt becomes a value affected by the inflection point of (see FIG. 4). Note that the different types of tires are unknown tires that are not genuine tires, but it is assumed that all four wheels have the same tires.

[0025] Next, the heat generation amount calculation unit 8 calculates the heat generation amount QG of the tire 3 of each wheel 2i i In order to calculate, based on the steering angle δ and the traveling speed V of the vehicle 1, for example, from a two-wheel model, the longitudinal slip speed V of each wheel 2i (of the tire 3) SLPXi and the lateral slip speed V SLPYi are calculated. Then, as shown in FIG. 4, this longitudinal slip speed V SLPXi and the lateral slip speed V SLPYi and the longitudinal force F of each wheel 2i (of the tire 3) Xi and the lateral force F Yi and the tire longitudinal heat storage coefficient W Xi and the tire lateral heat storage coefficient W Yi are used to calculate the heat generation amount (tire heat generation amount) QG generated between the tire 3 of each wheel 2i and the road surface according to the following equation (12). Here, as is clear from the unit of the tire heat generation amount QG i [°C / s]. The calculated tire heat generation amount QG i is the temperature increase amount of the tire 3 per unit time, that is, what can be called the tire temperature increase rate.

[0026]

Equation

[0027] Next, the previous temperature acquisition unit 20 shown in FIG. 1 acquires the surface temperature of the tire 3 of each wheel 2i calculated by the surface temperature calculation unit 11 described later as the previous surface temperature (previous tire surface temperature) T of the tire 3 of each wheel 2i 0i [°C]. The initial value of the previous tire surface temperature T 0i is the outside air temperature T detected by the outside air temperature sensor 26 AIR . Using this previous tire surface temperature T 0i ​​​​Calculate the [℃ / s]. First tire heat dissipation QD1 i As shown in Figure 4, this is the amount of heat dissipated from the tires 3 of each wheel 2i to the road surface, and the road surface temperature T obtained by the road surface temperature acquisition unit 18. ROAD The following 13 equations are used to obtain the result. Note that the road surface heat dissipation coefficient κ1 [1 / s] in the equation may be set to be larger as the road surface temperature decreases. In addition, the second heat dissipation amount calculation unit 9b in the heat dissipation amount calculation unit 9 uses the previous tire surface temperature T 0i Using this, the second heat dissipation amount (second tire heat dissipation amount) QD2 of the tire 3 of each wheel 2i is calculated. i Calculate the [℃ / s]. This is the heat dissipation of the second tire QD2. i This refers to the ambient temperature T obtained by the ambient temperature acquisition unit 19. AIR and tire internal temperature T INRi Based on this, the following equation 14 is obtained, and as shown in Figure 4, it includes the amount of heat dissipated from the tire 3 of each wheel 2i to the outside air QD21 (first term on the right side of equation 14) and the amount of heat dissipated from the tire 3 to the air inside the tire QD22 (second term on the right side of equation 14). Note that the outside air heat dissipation coefficient κ2 in the equation is the outside air temperature T AIR The smaller the value, the larger the value is set. Also, the internal heat dissipation coefficient κ3 in the formula is the internal temperature of the tire T INRi It may be set so that the smaller the value, the larger the value becomes.

[0028]

number

[0029] Here, the heat dissipation amount of the first tire QD1 i and second tire heat dissipation QD2 i As is clear from the units, the calculated first tire heat dissipation QD1 i and second tire heat dissipation QD2 i This is the amount of temperature decrease of tire 3 per unit time, or what can be called the tire temperature decrease rate. Note that only the amount of heat dissipated from tire 3 to the outside air QD21 or the amount of heat dissipated from tire 3 to the air inside the tire QD22 is referred to as the second tire heat dissipation QD2 i This may also be done. The temperature change amount calculation unit 10 calculates the tire heat generation amount QG i From the first tire heat dissipation QD1i and second tire heat dissipation QD2 i Subtracting this, the temperature change (tire temperature change) dT of the surface temperature of the tire 3 of each wheel 2i is calculated according to the following equation 15. i Calculate / dt[℃ / s]. Also, the tire heat generation QG of type 15. i Substituting equation 12 into the given equation yields equation 16 below. Here, tire temperature change dT i As is clear from the unit / dt, the calculated tire temperature change amount dT i / dt represents the rate of change in tire temperature 3 per unit time, or the tire temperature change rate. The surface temperature calculation unit 11 then calculates the previous tire surface temperature T 0i and tire temperature change dT i Based on / dt, the surface temperature of each wheel 2i tire 3 (tire surface temperature T) i Calculate.

[0030]

number

[0031] The calculation process in the above-mentioned functional unit is shown in the flowchart of Figure 5. In the calculation process according to this flowchart, first in step S1, the heat generation unit 8 calculates the vertical load F of each wheel 2i according to equations 1 to 6 above. Zi Next, in step S2, the heat generation calculation unit 8 calculates the longitudinal force F of each wheel 2i according to equations 7 to 11 above. Xi and lateral force F Yi Next, in step S3, the heat generation calculation unit 8 calculates the vertical load F of each wheel 2i by referring to the map above. Zi and vertical force F Xi and lateral force F Yi The heat storage coefficient W of the tire 3 of each wheel 2i corresponds to Xi , W Yi Next, in step S4, the heat generation calculation unit 8 calculates the slip speed V of each wheel 2i. SLPXi , V SLPYi Next, in step S5, the heat generation calculation unit 8 calculates the longitudinal force F of each wheel 2i according to the above equation 12. Xi and lateral force FYi The heat storage coefficient W of the tire 3 of each wheel 2i Xi , W Yi , slip speed V of each wheel 2i SLPXi , V SLPYi QG of tire heat generation for each wheel 2i according to the corresponding values i Next, in step S6, the road surface temperature acquisition unit 18 calculates the road surface temperature T ROAD Next, in step S7, the ambient temperature acquisition unit 19 obtains the outside air temperature T AIR Next, in step S8, the ambient temperature acquisition unit 19 obtains the internal tire temperature T of each wheel 2i. INRi The following is obtained. Here, the processes in steps S6 to S8 may be executed in any order, or they may be executed simultaneously. Also, either step S7 or step S8 may be performed alone. Next, in step S9, the heat dissipation amount calculation unit 9 obtains the previous tire surface temperature T 0i and road surface temperature T ROAD Using the above formula 13, the heat dissipation QD1 of the first tire of each wheel 2i i In addition to calculating the previous tire surface temperature T 0i and outside air temperature T AIR and tire internal temperature T INRi Using the above formula 14, the heat dissipation QD2 of the second tire of each wheel 2i i The following is calculated. As mentioned above, the heat dissipation amount of the second tire QD2 i This may be only the first term on the right-hand side of the above equation 14, or only the second term. Next, in step S10, the temperature change amount calculation unit 10 calculates the tire heat generation amount QG i , 1st tire heat dissipation QD1 i , and the heat dissipation of the second tire QD2 i Using the above equations 15 to 16, the change in tire temperature dT of each wheel 2i i / dt is calculated. Then, in step S11, the surface temperature calculation unit 11 calculates the previous tire surface temperature T of each wheel 2i. 0i and tire temperature change dT i Tire surface temperature T using / dt i Calculate.

[0032] Next, an overview of the calculation processes performed in each functional unit of the tire surface temperature control unit 7 will be described. In the tire temperature difference calculation unit 7a of the tire surface temperature control unit 7, the front tire surface temperature T of the front wheels 2FR and 2FL is calculated. F Rear tire surface temperature T RE The difference value is the temperature difference ΔT before and after. FR In addition to calculating the tire surface temperature T of the left wheel 2FL and 2RL L The tire surface temperature of the right wheel 2FR and 2RR is T RI The difference in temperature between the left and right sides ΔT LR The front and rear wheel load control unit 7b calculates the front and rear temperature difference ΔT. FR The first difference between front and back is a predetermined value ΔT FR01 In the above cases, the temperature difference ΔT is determined according to the control map in Figure 7 described above. FR Accordingly, the system selects between front and rear wheel load adjustment by aerodynamic adjustment and front and rear wheel load adjustment by braking force adjustment, and outputs control commands to the braking force controller 12a and aerodynamic controller 13a according to the amount of front wheel load increase correction in the selected front and rear wheel load adjustment. In addition, the left and right wheel friction force control unit 7c controls the left and right temperature difference ΔT LR The first left-right difference is a predetermined value ΔT LR01 In the above cases, the left-right temperature difference ΔT is determined according to the control map in Figure 8 described above. LR Accordingly, the system selects between left and right wheel friction force adjustment by aerodynamic adjustment, left and right wheel friction force adjustment by damping force adjustment, and left and right wheel friction force adjustment by roll angle adjustment. It also outputs control commands to the aerodynamic controller 13a and suspension controller 14a corresponding to the amount of correction for the increase in inner wheel friction force during cornering in the selected left and right wheel friction force adjustment. This calculation process is summarized in the flowchart of Figure 9. This calculation process is executed, for example, by a timer interrupt process with a predetermined sampling period.

[0033] In this calculation process, first in step S21, the tire surface temperature T of each wheel 2i, calculated by the surface temperature calculation unit 11, is used. i The data is then read. Next, the process moves to step S22, and the front tire surface temperature T of the front wheels 2FR and 2FL, which was read in step S21, is read. F Rear tire surface temperature T REThe difference value is the temperature difference ΔT before and after. FR The following is calculated. In the calculation, for example, the tire surface temperature T of the front wheels 2FR and 2FL is used. FR , T FL The average value of the front tire surface temperature T F The tire surface temperature T of the rear wheels 2RR and 2RL respectively. RR , T RL The average value of the rear tire surface temperature T RE Examples include the above. Next, proceed to step S23, and the temperature difference ΔT calculated in step S22 is used. FR The first difference between front and back is a predetermined value ΔT FR01 Determine whether the above is true or not, and the temperature difference ΔT before and after. FR The first difference between front and back is a predetermined value ΔT FR01 If the above is true, proceed to step S24; otherwise, proceed to step S25. In step S24, the temperature difference ΔT is determined according to the control map in Figure 7. FR The front wheel load increase correction amount and the front and rear wheel load adjustment amounts (= front wheel load increase correction amount) based on the respective front and rear wheel load adjustments are calculated. In step S25, the left wheel tire surface temperature T of the left wheel 2FL and 2RL read in step S21 is calculated. L The right wheel 2FR, 2RR right wheel tire surface temperature T RI The difference in temperature between the left and right sides ΔT LR The following is calculated. For example, the tire surface temperature T of the left wheel 2FL and 2RL is used in the calculation. FL , T RL The average value of the left wheel tire surface temperature T L The tire surface temperatures T for the right wheel 2FR and 2RR respectively. FR , T RR The average value of the right wheel tire surface temperature T RI Examples include the following. Next, proceed to step S26, and the left-right temperature difference ΔT calculated in step S25 is used. LR The first left-right difference is a predetermined value ΔT LR01 Determine whether the above is true or not, and the temperature difference between the left and right sides ΔT LR The first left-right difference is a predetermined value ΔT LR01If the above is true, proceed to step S27; otherwise, proceed to step S29. In step S27, identify either the left wheel 2FL, 2RL or the right wheel 2FR, 2RR as the turning inner wheel. For identification, for example, the output of the steering angle sensor 21 can be used. Also, the left wheel tire surface temperature T L and the right wheel tire surface temperature T RI The smaller of the two wheels 2i may be designated as the inner turning wheel. Next, proceed to step S28, and according to the control map in Figure 8, the left-right temperature difference ΔT LR The system calculates the amount of correction for the increase in turning inner wheel friction force and the amount of adjustment for the left and right wheel friction force due to the adjustment of each turning inner wheel friction force (= turning inner wheel friction force correction amount). Next, the system moves to step S29, where it outputs control commands to each controller 12a to 14a according to the front and rear wheel load adjustment amount calculated in step S24 and the left and right wheel friction force adjustment amount calculated in step S28, and then returns to the starting position.

[0034] According to this calculation process, the calculated temperature difference ΔT FR The first difference between front and back is a predetermined value ΔT FR01 If the above conditions are met, the temperature difference ΔT will be controlled according to the control map in Figure 7. FR The corresponding front wheel load increase correction amount and the front and rear wheel load adjustment amounts based on the respective front and rear wheel load adjustments are calculated. Similarly, the left-right temperature difference ΔT is calculated. LR The first left-right difference is a predetermined value ΔT LR01 If the above conditions are met, the left-right temperature difference ΔT will be controlled according to the control map in Figure 8. LR The amount of correction for the increase in turning inner wheel friction force and the amount of adjustment for the left and right wheel friction force based on the adjustment of each turning inner wheel friction force are calculated accordingly. Then, control commands corresponding to the calculated front and rear wheel load adjustment amounts and left and right wheel friction force adjustment amounts are output to each controller 12a to 14a. Accordingly, each controller 12a to 14a performs aerodynamic adjustment by the canard 30, damping force adjustment for vibration of the wheel 2i by the active suspension, and roll angle adjustment of the vehicle body 38 by the active suspension. As a result, front wheel load increase correction and / or turning inner wheel friction force increase correction are performed, and the front wheel tire surface temperature T of the front wheels 2FR and 2FL is reduced. FThe maximum friction coefficient of the tires 3 of each wheel 2i is maintained in a good state by reducing the friction force of the turning outer wheel and by reducing the tire surface temperature of the turning outer wheel. In one example, the above control method made it possible to reduce the temperature difference between the tire surface temperatures of the front and rear wheels, and also to reduce the temperature difference between the tire surface temperatures of the left and right wheels (turning inner and outer wheels). More specifically, the temperature difference between the tire surface temperatures of the front and rear wheels was reduced by increasing the load on the front wheel through aerodynamic adjustment, and the temperature difference between the tire surface temperatures of the front and rear wheels was reduced by increasing the load on the front wheel through braking and driving force adjustment. Furthermore, during turning, the temperature difference between the tire surface temperatures of the left and right wheels (turning inner and outer wheels) was reduced by increasing the friction force of the turning inner wheel through aerodynamic adjustment, the temperature difference between the tire surface temperatures of the left and right wheels (turning inner and outer wheels) was reduced by increasing the friction force of the turning inner wheel through damping force adjustment, and the temperature difference between the tire surface temperatures of the left and right wheels (turning inner and outer wheels) was reduced by increasing the friction force of the turning inner wheel through roll angle adjustment.

[0035] Thus, in this embodiment, the tire surface temperature T of each wheel 2i of a vehicle equipped with a front and rear wheel load adjustment device that can adjust the load of the front wheels 2FR, 2FL and the rear wheels 2RR, 2RL is measured. i When controlling the tire surface temperature T of each wheel 2i, i The calculated tire surface temperature T i Tire surface temperature T of front and rear wheels 2F, 2R i Temperature difference ΔT FR The first difference between front and back is a predetermined value ΔT FR01 If the above conditions are met, the load on the front and rear wheels is controlled by the front and rear wheel load adjustment device so that the load on the front wheels 2FR and 2FL is increased. This increases the tire surface temperature T i For the front 2FR and 2FL tires, which tend to have a higher temperature, increasing the load on the front 2FR and 2FL tires will increase the tire surface temperature T F This allows for a reduction in the force that can be generated by tire 3, and as a result, it becomes possible to keep the force within a good range. Furthermore, the front and rear wheel load adjustment device includes an aerodynamic adjustment means for adjusting the load on the front and rear wheels by aerodynamics, and a braking force adjustment means for adjusting the load on the front and rear wheels by the braking force of the vehicle, with a front-to-rear temperature difference ΔTFR The first difference between front and back is a predetermined value ΔT FR01 The above and the second front-to-back difference predetermined value ΔT FR02 If the value is less than the specified value, the load adjustment of the front and rear wheels by the aerodynamic adjustment means is selected, and the second front-to-rear difference is a predetermined value ΔT. FR02 The above and the third front-to-back difference predetermined value ΔT FR03 If the tire surface temperature T is less than the specified value, the load adjustment of the front and rear wheels by the braking and driving force adjustment means is selected, and the load adjustment of the front and rear wheels by the aerodynamic adjustment means and the braking and driving force adjustment means is selected or added in order of least unnaturalness in vehicle behavior. This allows the tire surface temperature T to be determined without the occupants of vehicle 1 knowing. i It can be kept within an appropriate range.

[0036] Also, the temperature difference ΔT FR As the aerodynamic adjustment mechanism increases, the amount of load adjustment on the front and rear wheels is monotonically increased, thereby adjusting the tire surface temperature T i It can be kept within an appropriate range. Furthermore, the second predetermined value of the difference between front and rear ΔT FR02 By setting the load adjustment amount of the front and rear wheels by the aerodynamic adjustment means in accordance with the specifications of tire 3 so as to suppress the load on tire 3, the tire surface temperature T of the front wheels 2FR and 2FL is reduced. i This can prevent the problem from increasing. Also, the temperature difference ΔT FR As the value increases, the amount of load adjustment on the front and rear wheels by the braking and driving force adjustment means is monotonically increased, thereby adjusting the braking and driving force to change the tire surface temperature T i It can be kept within an appropriate range. Furthermore, the third predetermined value of the difference between front and rear ΔT FR03 The amount of load adjustment of the front and rear wheels by the braking and driving force adjustment means is defined so that the amount of load adjustment of the front and rear wheels by the braking and driving force adjustment means is less than or equal to the amount of load adjustment that does not cause discomfort to the vehicle occupants, thereby preventing the occupants of vehicle 1 from knowing about the tire surface temperature T i It can be kept within an appropriate range.

[0037] Furthermore, it has a left and right wheel friction force adjustment means that can adjust the friction force of the left and right wheels, and the calculated tire surface temperature T iTire surface temperature T of left and right wheels 2L, 2RI i The temperature difference between the left and right sides ΔT LR The first left-right difference is a predetermined value, and the left-right temperature difference is ΔT. LR01 If the above conditions are met, the friction force of the left and right wheels is controlled by the left and right wheel friction force adjustment device so that the load on the turning inner wheel is increased. This increases the tire surface temperature T i By increasing the frictional force of the inner turning wheel relative to the outer turning wheel tire 3, which is prone to temperature increases, the tire surface temperature of the inner turning wheel can be lowered, and as a result, the force that the tire 3 can generate can be kept within a good range. Furthermore, the left and right wheel friction force adjustment device includes an aerodynamic adjustment means for adjusting the friction force of the left and right wheels by aerodynamics, a damping force adjustment means for adjusting the friction force of the left and right wheels by the damping force against vertical vibration of each wheel, and a roll angle adjustment means for adjusting the friction force of the left and right wheels by the roll angle of the vehicle body, and the left and right temperature difference ΔT LR The first left-right difference is a predetermined value ΔT LR01 The above and the second left-right difference predetermined value ΔT LR02 If it is less than the value, the friction force adjustment of the left and right wheels by the aerodynamic adjustment means is selected, and the second left-right difference predetermined value ΔT LR02 The above and the third left-right difference predetermined value ΔT LR03 If it is less than the third left-right difference predetermined value ΔT, the damping force adjustment means is selected to adjust the friction force of the left and right wheels. LR03 The above and the fourth left-right difference predetermined value ΔT LR04 If the tire surface temperature T is less than the specified value, the friction force adjustment of the left and right wheels using the roll angle adjustment means is selected, and the friction force adjustment of the left and right wheels using the aerodynamic adjustment means, damping force adjustment means, and roll angle adjustment means is selected or added in order of least discomfort with the vehicle's behavior. This allows the tire surface temperature T to be adjusted without the occupants of vehicle 1 knowing. i It can be kept within an appropriate range.

[0038] Also, the temperature difference between the left and right sides ΔT LR As the aerodynamic adjustment mechanism increases, the amount of frictional force adjustment between the left and right wheels is monotonically increased, thereby adjusting the tire surface temperature T i It can be kept within an appropriate range. Furthermore, the second left-right difference predetermined value ΔT LR02By setting the amount of frictional force adjustment between the left and right wheels by the aerodynamic adjustment means according to the specifications of tire 3 so as to suppress the load on tire 3, the tire surface temperature T of the turning inner wheel is reduced. i This can prevent the problem from increasing. Also, the temperature difference between the left and right sides ΔT LR As the value increases, the amount of friction force adjustment between the left and right wheels by the damping force adjustment means is monotonically increased, thereby adjusting the damping force to control the tire surface temperature T i It can be kept within an appropriate range. Furthermore, the third left-right difference is a predetermined value ΔT LR03 The amount of friction force adjustment of the left and right wheels by the damping force adjustment means is defined so that the amount of friction force adjustment of the left and right wheels by the damping force adjustment means is less than or equal to the amount of friction force adjustment that does not cause discomfort to the vehicle occupants, thereby preventing the occupants of vehicle 1 from knowing about the tire surface temperature T i It can be kept within an appropriate range. Also, the temperature difference between the left and right sides ΔT LR As the roll angle increases, the amount of frictional force adjustment between the left and right wheels by the roll angle adjustment means is monotonically increased. As a result, the tire surface temperature T is increased by adjusting the roll angle. i It can be kept within an appropriate range. Furthermore, the fourth left-right difference predetermined value ΔT LR04 The amount of frictional force adjustment between the left and right wheels by the roll angle adjustment means is defined so that the amount of frictional force adjustment between the left and right wheels by the roll angle adjustment means is less than or equal to the amount of frictional force adjustment that does not cause discomfort to the vehicle occupants. As a result, the tire surface temperature T is not noticed by the occupants of vehicle 1. i It can be kept within an appropriate range.

[0039] Although the tire surface temperature control system according to the embodiment has been described above, the present invention is not limited to the configuration described in the above embodiment, and various modifications are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0040] 1...Vehicle, 2i...Wheel, 3...Tire, 4...Tire surface temperature control device, 5...Processor (arithmetic processing unit), 6...Tire surface temperature calculation unit, 7...Tire surface temperature control unit, 7a...Tire temperature difference calculation unit, 7b...Front and rear wheel load control unit, 7c...Left and right wheel friction force control unit, 8...Heat generation amount calculation unit, 9...Heat dissipation amount calculation unit, 10...Temperature change amount calculation unit, 11...Surface temperature calculation unit, 12...Drive source (front and rear wheel load adjustment device, braking force adjustment means), 12a...Breaking force controller (front and rear wheel load adjustment device, braking force adjustment means), 13...Canard motor (front and rear wheel load adjustment (Adjustment device, left and right wheel friction force adjustment device, aerodynamic adjustment means), 13a...Aerodynamic controller (front and rear wheel load adjustment device, left and right wheel friction force adjustment device, aerodynamic adjustment means), 14...Hydraulic control valve (left and right wheel friction force adjustment device, damping force adjustment means, roll angle adjustment means), 14a...Suspension controller (left and right wheel friction force adjustment device, damping force adjustment means, roll angle adjustment means), 30...Canard (front and rear wheel load adjustment device, left and right wheel friction force adjustment device, aerodynamic adjustment means), 33...Hydraulic cylinder (left and right wheel friction force adjustment device, damping force adjustment means, roll angle adjustment means), 38...Vehicle body

Claims

1. A tire surface temperature control method for controlling the surface temperature of tires mounted on each wheel of a vehicle equipped with front and rear wheel load adjustment means capable of adjusting the load on the front and rear wheels, A tire surface temperature calculation step for calculating the surface temperature of the tire on each wheel, A tire surface temperature control method characterized by comprising: a wheel load control step, which controls the loads of the front and rear wheels by the front and rear wheel load adjusting means so as to increase the load of the front wheel when the front and rear temperature difference between the front and rear tire surface temperatures of the front and rear wheels in the calculated tire surface temperature is greater than or equal to a first front-to-rear difference predetermined value.

2. The front and rear wheel load adjustment means comprises an aerodynamic adjustment means for adjusting the load of the front and rear wheels by aerodynamics, and a braking force adjustment means for adjusting the load of the front and rear wheels by the braking force of the vehicle. The tire surface temperature control method according to claim 1, characterized in that the wheel load control step selects to adjust the load of the front and rear wheels by the aerodynamic adjustment means when the front-to-rear temperature difference is greater than or equal to a first predetermined front-to-rear difference value and less than a second predetermined front-to-rear difference value that is greater than the first predetermined front-to-rear difference value, selects to adjust the load of the front and rear wheels by the braking force adjustment means when the front-to-rear temperature difference is greater than or equal to a second predetermined front-to-rear difference value and less than a third predetermined front-to-rear difference value that is greater than the second predetermined front-to-rear difference value, and selects or adds the load adjustments of the front and rear wheels by the aerodynamic adjustment means and the braking force adjustment means in order of least discomfort to the vehicle behavior.

3. The tire surface temperature control method according to claim 2, characterized in that the amount of load adjustment of the front and rear wheels by the aerodynamic adjustment means is monotonically increased as the front-to-rear temperature difference increases.

4. The tire surface temperature control method according to claim 2, characterized in that the amount of load adjustment of the front and rear wheels by the aerodynamic adjustment means at the second predetermined front-to-rear difference is set according to the specifications of the tire so as to suppress the load on the tire.

5. The tire surface temperature control method according to claim 2, characterized in that the amount of load adjustment of the front and rear wheels by the braking force adjustment means is monotonically increased as the temperature difference between the front and rear increases.

6. The tire surface temperature control method according to claim 2, characterized in that the amount of load adjustment of the front and rear wheels by the braking and driving force adjustment means at the third predetermined front-to-rear difference is defined such that the amount of load adjustment of the front and rear wheels by the braking and driving force adjustment means is less than or equal to an amount of load adjustment that does not cause discomfort to the occupants of the vehicle.

7. The vehicle has a left and right wheel friction force adjustment means that can adjust the friction force of the left and right wheels, The tire surface temperature control method according to claim 1, further comprising a friction force control step in which, if the left-right temperature difference between the surface temperatures of the left and right wheels in the calculated tire surface temperature is greater than or equal to a first left-right difference predetermined value, the friction force of the left and right wheels is controlled by the left-right wheel friction force adjustment means so as to increase the load on the turning inner wheel.

8. The left and right wheel friction force adjusting means includes an aerodynamic adjusting means for adjusting the friction force of the left and right wheels by aerodynamics, a damping force adjusting means for adjusting the friction force of the left and right wheels by damping force against vertical vibration of each wheel, and a roll angle adjusting means for adjusting the friction force of the left and right wheels by the roll angle of the vehicle body. The friction force control step is characterized in that, when the left-right temperature difference is greater than or equal to a first predetermined left-right difference value and less than a second predetermined left-right difference value greater than the first predetermined left-right difference value, the friction force adjustment of the left and right wheels by the aerodynamic adjustment means is selected; when the temperature difference is greater than or equal to a second predetermined left-right difference value and less than a third predetermined left-right difference value greater than the second predetermined left-right difference value, the friction force adjustment of the left and right wheels by the damping force adjustment means is selected; when the temperature difference is greater than or equal to a third predetermined left-right difference value and less than a fourth predetermined left-right difference value greater than the third predetermined left-right difference value, the friction force adjustment of the left and right wheels by the roll angle adjustment means is selected or added in order of least unnaturalness in vehicle behavior.

9. The tire surface temperature control method according to claim 8, characterized in that the amount of frictional force adjustment between the left and right wheels by the aerodynamic adjustment means is monotonically increased as the temperature difference between the left and right wheels increases.

10. The tire surface temperature control method according to claim 8, characterized in that the amount of frictional force adjustment of the left and right wheels by the aerodynamic adjustment means at the second predetermined left-right difference is set according to the specifications of the tire so as to suppress the load on the tire.

11. The tire surface temperature control method according to claim 8, characterized in that the amount of friction force adjustment of the left and right wheels by the damping force adjustment means is monotonically increased as the temperature difference between the left and right wheels increases.

12. The tire surface temperature control method according to claim 8, characterized in that the amount of friction force adjustment of the left and right wheels by the damping force adjustment means at the third predetermined left-right difference is defined such that the amount of friction force adjustment of the left and right wheels by the damping force adjustment means is less than or equal to the amount of friction force adjustment that does not cause discomfort to the occupants of the vehicle.

13. The tire surface temperature control method according to claim 8, characterized in that the amount of frictional force adjustment of the left and right wheels by the roll angle adjustment means is monotonically increased as the temperature difference between the left and right sides increases.

14. The tire surface temperature control method according to claim 8, characterized in that the amount of frictional force adjustment of the left and right wheels by the roll angle adjustment means at the fourth predetermined left-right difference is defined such that the amount of frictional force adjustment of the left and right wheels by the roll angle adjustment means is less than or equal to the amount of frictional force adjustment that does not cause discomfort to the occupants of the vehicle.

15. A tire surface temperature control device that controls the surface temperature of tires mounted on each wheel of a vehicle equipped with front and rear wheel load adjustment means capable of adjusting the load on the front and rear wheels and left and right wheel friction force adjustment means capable of adjusting the friction force on the left and right wheels, using a controller, The aforementioned controller, A tire surface temperature calculation unit that calculates the surface temperature of the tire on each wheel, If the front-to-rear temperature difference between the front and rear tire surface temperatures of the front and rear wheels in the calculated tire surface temperature is greater than or equal to a first front-to-rear difference predetermined value, the wheel load control unit controls the load of the front and rear wheels by the front and rear wheel load adjustment means so as to increase the load on the front wheel. A tire surface temperature control device comprising: a friction force control unit that controls the friction force of the left and right wheels by a left and right wheel friction force adjustment means so as to increase the friction force of the turning inner wheel when the left and right temperature difference between the surface temperatures of the left and right wheels of the calculated tire surface temperature is greater than or equal to a first left-right difference predetermined value.

Images