WO2023134414A1 - Brake disc temperature determining method and apparatus, and vehicle - Google Patents

Abstract

A brake disc temperature determining method and apparatus, and a vehicle. The brake disc temperature determining method comprises: when a high-temperature re-clamping function is available, determining an initialization temperature of a brake disc according to a relationship between a brake disc temperature of a previous period and an ambient temperature; in a non-dynamic braking working condition, determining a raised temperature of the brake disc according to a wheel speed pulse and a wheel cylinder pressure, or in a dynamic braking working condition, determining a raised temperature of the brake disc according to a vehicle speed; determining a reduced temperature of the brake disc according to a relationship of temperature reduction of the brake disc along with the vehicle speed; and determining the temperature of the brake disc according to the initialization temperature and a difference between the raised temperature of the brake disc and the reduced temperature of the brake disc.

Description

Brake disc temperature determination method, device and vehicle

This application claims the priority of the Chinese patent application with application number 202210047035.5 submitted to the China Patent Office on January 14, 2022, the entire content of which is incorporated herein by reference.

technical field

The present application relates to the technical field of vehicle braking, for example, to a method and device for determining the temperature of a brake disc, and a vehicle.

Background technique

In the automotive field, the electronic parking brake (Electrical Park Brake, EPB) system can not only provide safety for the vehicle, but also provide driving assistance for the driver, such as automatically releasing the brake when the vehicle starts, or starting on an inclined slope. Realize ramp control etc.

However, during the running of the vehicle, frequent braking will cause a severe temperature rise of the brake disc and friction lining in the EPB system, and the expansion coefficient of the brake disc will also be in a state of continuous change. When the temperature of the brake disc drops, due to thermal expansion and contraction, the brake disc will shrink adaptively. At this time, the actual clamping force of the caliper is less than the clamping force required by the EPB system, so there are risks such as sliding slopes. Based on this, the EPB system needs to perform a high-temperature re-clamp operation, and the high-temperature re-clamp operation requires confirmation of the brake disc temperature. However, the method for confirming the temperature of the brake disc is difficult to implement and is prone to misalignment, such as confirming the temperature of the brake disc through a temperature sensor.

Contents of the invention

The present application provides a brake disc temperature determination method, device and vehicle, to reduce the implementation difficulty of the brake disc temperature confirmation, improve the confirmation accuracy of the brake disc temperature, facilitate the EPB system to perform high temperature re-clamping operations, and avoid vehicle slippage. slope risk.

In a first aspect, the present application provides a method for determining the temperature of a brake disc, including:

When the high temperature reclamp function is available, the initialization temperature of the brake disc is determined according to the relationship between the brake disc temperature and the ambient temperature in the last cycle;

In the case of non-dynamic braking, the temperature rise of the brake disc is determined according to the wheel speed pulse and the pressure of the wheel cylinder, or in the case of dynamic braking, the temperature rise of the brake disc is determined according to the vehicle speed;

Determine the cooling of the brake disc according to the cooling relationship of the brake disc with the speed of the vehicle;

The temperature of the brake disc is determined according to the initialization temperature and the result of subtracting the temperature reduction of the brake disc from the temperature rise of the brake disc.

Brake disc heating is determined based on wheel speed pulses and wheel cylinder pressure, including:

The temperature rise of the current brake disc is equal to the temperature generated by the wheel cylinder pressure and the wheel speed pulse work.

The wheel cylinder pressure per unit and the temperature generated by pulse work per wheel speed are determined in the following manner:

In the formula, F _x represents the longitudinal force of the wheel, d represents the radius of the caliper piston, μ represents the friction coefficient of the friction plate, re represents the effective radius of the brake disc, R ₀ represents the rolling radius of the wheel, and W ₁ represents the The wheel cylinder pressure and the work done by the unit wheel speed pulse, S represents the braking distance, _T1 represents the temperature rise of the brake disc, and _M1 represents the conversion coefficient of heat energy converted into temperature rise.

In dynamic braking conditions, the temperature rise of the brake disc is determined according to the vehicle speed, including:

If dynamic braking is performed and the vehicle speed in the previous cycle is greater than the current cycle speed, the heat of the brake disc heating up is the heat generated by the kinetic energy of the speed drop;

If dynamic braking is performed and the vehicle speed in the last cycle is lower than the vehicle speed in the current cycle, the heating heat of the brake disc is 0.

If dynamic braking is applied and the vehicle speed in the previous cycle is greater than the vehicle speed in the current cycle, the temperature rise of the brake disc is determined as follows:

In the formula, W2 represents the amount of heat energy converted from kinetic energy, K2 represents the conversion coefficient of kinetic energy into heat energy, V2 represents the kinetic energy at the vehicle speed of the previous cycle, and V1 represents the kinetic energy at the vehicle speed of the current cycle.

It also includes: when the brake disc temperature is greater than the maximum value of the external environment temperature, the brake disc temperature is lower than the minimum value of the external environment temperature, when the brake disc temperature value is wrong or when the brake disc temperature is unreliable, the preset temperature is used as the temperature of the brake disc.

According to the relationship between the brake disc temperature in the last cycle and the ambient temperature, determine the initialization temperature of the brake disc, including:

When the brake disc temperature is lower than the external ambient temperature, the initialization temperature of the brake disc is equal to the external ambient temperature;

When the temperature of the brake disc is higher than the temperature of the external environment, the initial temperature of the brake disc is equal to the temperature of the brake disc in the last cycle minus the temperature ΔT that decreases with the sleep time, where the temperature ΔT is the difference between the temperature of the brake disc in the last cycle and The difference in ambient temperature.

The cooling of the brake disc is determined in the following way:

T ₂ =K ₃ ·ΔT

In the formula, T ₂ represents the temperature drop of the brake disc, and K ₃ represents the temperature drop coefficient of the brake disc with the vehicle speed.

In a second aspect, the present application also provides a brake disc temperature determination device, including:

The initialization temperature confirmation module is set to determine the initialization temperature of the brake disc according to the relationship between the brake disc temperature and the ambient temperature in the previous cycle when the high temperature re-clamp function is available;

The temperature rise determination module is configured to determine the temperature rise of the brake disc according to the wheel speed pulse and wheel cylinder pressure in non-dynamic braking conditions, or determine the temperature rise of the brake disc according to the vehicle speed in dynamic braking conditions;

The cooling determination module is configured to determine the cooling of the brake disc according to the cooling relationship of the brake disc with the speed of the vehicle;

The temperature confirmation module is configured to determine the temperature of the brake disc according to the initialization temperature and the result of the temperature rise of the brake disc minus the temperature drop of the brake disc.

In a third aspect, the present application also provides a vehicle, which is integrated with the brake disc temperature determination device provided in the present application.

In a fourth aspect, the present application further provides a computer-readable storage medium storing a computer program, and when the program is executed by a processor, the method for determining the brake disc temperature provided in the present application is realized.

Description of drawings

FIG. 1 is a flow chart of a method for determining the temperature of a brake disc provided in an embodiment of the present application;

FIG. 2 is a flow chart of another method for determining the temperature of a brake disc provided in an embodiment of the present application;

Fig. 3 is a flow chart of another method for determining the temperature of a brake disc provided in an embodiment of the present application;

Fig. 4 is a flow chart of another method for determining the temperature of a brake disc provided in an embodiment of the present application;

Fig. 5 is a schematic structural diagram of a brake disc temperature determination device provided by an embodiment of the present application.

Detailed ways

The application will be described below in conjunction with the accompanying drawings and embodiments. The specific embodiments described herein are for illustration of the application only. For ease of description, only parts relevant to the present application are shown in the drawings.

Figure 1 is a flow chart of a method for determining the temperature of a brake disc provided by the embodiment of the present application. This embodiment is applicable to the confirmation of the temperature of the brake disc of any vehicle equipped with a brake system composed of brake discs, friction plates, etc. Scenarios, vehicles such as automobiles, motorcycles, etc., the method can be executed by, but not limited to, the device for determining the temperature of the brake disc in the embodiment of the present application as the execution subject, and the execution subject can be implemented in the form of software and/or hardware. As shown in Figure 1, the method for determining the brake disc temperature includes the following steps:

S110. When the high-temperature re-clamp function is available, determine the initialization temperature of the brake disc according to the relationship between the brake disc temperature and the ambient temperature in the last cycle.

, The high temperature re-clamping function means that when the vehicle is in the parking state, the temperature of the brake disc exceeds the preset temperature and meets the set time limit, and the EPB system controls the caliper to clamp again for parking. Therefore, the high-temperature re-clamping function may mean that the EPB system can effectively control the caliper to re-clamp and park after the vehicle-related parameters meet the aforementioned conditions.

The temperature of the brake disc in the last cycle can be the temperature of the brake disc at any time before the current cycle. For example, compared with the temperature of the brake disc in the current cycle, the temperature of the brake disc in the last cycle can be, but not limited to, 500ms ago, Brake disc temperature 2s ago or 4s ago. In the embodiment of the present application, the temperature of the brake disc in the last cycle may be the temperature of the brake disc 1 second ago.

In addition, the brake disc can include a left rear brake disc and a right rear brake disc. The structure of the brake disc can be a solid disc, a hollow disc, a perforated disc or a perforated and lined disc, etc. The material of the brake disc Can be but not limited to cast iron, carbon fiber and ceramics.

The relationship between the brake disc temperature and the ambient temperature in the last cycle can include three situations, that is, the brake disc temperature in the last cycle is greater than the ambient temperature, the brake disc temperature in the last cycle is equal to the ambient temperature, and the brake disc temperature in the last cycle is equal to the ambient temperature. The temperature of the moving plate is lower than the ambient temperature. The initialization temperature of the brake disc is the temperature of the brake disc at the end of the previous cycle and the beginning of the current cycle.

S120. In the non-dynamic braking condition, determine the temperature rise of the brake disc according to the wheel speed pulse and the wheel cylinder pressure, or determine the temperature rise of the brake disc according to the vehicle speed in the dynamic braking condition.

Non-dynamic braking conditions refer to the conditions in which the driver depresses the brake pedal for braking. When the driver steps on the brake pedal, the left front brake disc, the right front brake disc, the left rear brake disc and the right rear brake disc are all under the action of the brake oil pressure and brake through friction heat generation. The kinetic energy of the vehicle converted into the total temperature rise heat energy of the brake disc is equal to the sum of the temperature rise heat energy of the left front brake disc, right front brake disc, left rear brake disc and right rear brake disc, therefore, by converting into the total temperature rise of the brake disc It is difficult to calculate the temperature rise heat energy of the left rear brake disc and the right rear brake disc controlled by the EPB system from the vehicle kinetic energy of heat energy. In view of this, the method of determining the temperature rise of the brake disc according to the wheel speed pulse and the wheel cylinder pressure provided by this embodiment can better meet the actual working conditions of the non-dynamic braking of the EPB system, and can effectively improve the temperature of the left rear brake disc and the right brake disc. The calculation accuracy of the heat energy of the temperature rise of the rear brake disc can accurately calculate the temperature rise of the left rear brake disc and the right rear brake disc.

In addition, the wheel speed pulse refers to the wheel speed signal detected by the wheel speed sensor, and the pulse signal generated after processing the input channel. Exemplarily, the wheel speed sensor configured to generate wheel speed pulses may be a magnetoelectric wheel speed sensor, a Hall wheel speed sensor, or the like.

The wheel cylinder pressure refers to the pressure of the brake wheel cylinder, and the formation process of the wheel cylinder pressure can include mechanical, electromagnetic or fluid links. Exemplarily, the intermediate link formed by the wheel cylinder pressure may include a small hole flow link, a brake wheel cylinder pressure change link, a brake wheel cylinder piston movement link, and the like.

Dynamic braking conditions refer to the conditions in which the driver activates the EPB system to achieve vehicle braking, and the driver activates the EPB system and depresses the accelerator pedal. When the driver activates the EPB system to brake the vehicle, the heating heat of the left and right rear brake discs of the vehicle is converted from part of the kinetic energy of the vehicle; when the driver activates the EPB system and depresses the accelerator pedal, the EPB system Automatic release, the vehicle is in normal driving state. In view of this, for dynamic braking conditions, this embodiment can determine the temperature rise of the left rear brake disc and the right rear brake disc according to the vehicle speed, and can ensure the calculation accuracy of the temperature rise of the above brake discs.

S130. Determine the temperature drop of the brake disc according to the temperature drop relationship of the brake disc with the vehicle speed.

S140. Determine the temperature of the brake disc according to the initialization temperature and the temperature rise of the brake disc minus the temperature drop of the brake disc.

Determining the temperature of the brake disc based on the initialization temperature and the temperature rise of the brake disc minus the temperature drop of the brake disc means that the temperature of the brake disc is equal to the sum of the initialization temperature and the temperature rise of the brake disc, and then calculated with The difference obtained from the cooling of the brake disc.

In the embodiment of the present application, when the high-temperature reclamp function is available, the initialization temperature of the brake disc is determined according to the relationship between the brake disc temperature and the ambient temperature in the last cycle; in non-dynamic braking conditions, according to the wheel speed pulse and The wheel cylinder pressure determines the temperature rise of the brake disc, or in dynamic braking conditions, determines the temperature rise of the brake disc according to the vehicle speed; determines the temperature drop of the brake disc according to the relationship between the temperature drop of the brake disc and the speed of the vehicle; The temperature rise of the rotor minus the cooling of the brake disc determines the temperature of the brake disc. It can be seen that the embodiment of the present application divides the temperature of the brake disc into three components, that is, the initialization temperature, the temperature rise of the brake disc, and the temperature drop of the brake disc. The heating of the disc and the cooling of the brake disc are confirmed in sequence, and finally the temperature of the brake disc is determined. Based on this, the embodiment of the present application can effectively reduce the difficulty of confirming the brake disc temperature and improve the confirmation accuracy of the brake disc temperature, which is beneficial to the EPB system to perform precise high-temperature re-clamping operations and avoid the risk of vehicle slipping.

Any cycle in the embodiment of the present application can be refined into multiple signal sub-cycles. Exemplarily, any cycle can be refined into 100 signal sub-cycles. When the cycle length is 1s, the signal sub-cycle length is 10ms. Based on this, in one cycle, when the number of timed signal sub-cycles is less than 100, the embodiment of the present application only continuously accumulates the heat energy of the temperature rise of the left rear brake disc and the right rear brake disc, and does not calculate and output each The temperature of the brake disc under each signal sub-period, thus helping to reduce the calculation and communication pressure of the brake temperature confirmation device.

On the basis of the above-mentioned embodiments, the embodiments of the present application also illustrate the methods for determining the heating and cooling of the brake disc, which will be described below.

Fig. 2 is a flow chart of another method for determining the temperature of the brake disc provided in the embodiment of the present application. As shown in Fig. 2, the method for determining the temperature of the brake disc includes the following steps:

S210. When the high-temperature re-clamp function is available, determine the initialization temperature of the brake disc according to the relationship between the brake disc temperature and the ambient temperature in the last cycle.

S220. In non-dynamic braking conditions, the temperature rise of the current brake disc is equal to the temperature generated by the wheel cylinder pressure and the wheel speed pulse work, and if dynamic braking is performed and the vehicle speed in the previous cycle is greater than the current cycle speed, the temperature of the brake disc The heating heat is the heat generated by the speed drop kinetic energy; if dynamic braking is performed and the vehicle speed in the previous cycle is lower than the current cycle speed, the heating heat of the brake disc is 0.

The current temperature rise of the brake disc refers to the temperature rise of the brake disc in the current cycle.

In one cycle, the number of wheel speed pulses corresponding to different vehicle speeds is not the same. Based on this, in the non-dynamic braking condition, this embodiment takes 1Bar wheel cylinder pressure and 1 wheel speed pulse as an example. The method of confirming the wheel cylinder pressure and the temperature generated by the wheel speed pulse work is explained as follows:

The temperature generated by unit wheel cylinder pressure and unit wheel speed pulse work is determined by the following method:

In the formula, F _x represents the longitudinal force of the wheel, d represents the radius of the caliper piston, μ represents the friction coefficient of the friction plate, re represents the effective radius of the brake disc, R ₀ represents the rolling radius of the wheel, W ₁ represents the unit wheel cylinder pressure and unit The magnitude of the work done by the wheel speed pulse, S represents the braking distance, T ₁ represents the temperature rise of the brake disc, and M ₁ represents the conversion coefficient of heat energy converted into temperature rise.

The wheel longitudinal force refers to the component of the force acting on the wheel by the road surface along the longitudinal direction of the wheel coordinate system; the value range of μ can be 0.25~0.3, 0.35~0.5 or 0.55~0.6, etc.; for a vehicle, d, The values of re, R ₀ and M ₁ are relatively fixed; S is the braking distance under unit wheel cylinder pressure and unit wheel speed pulse.

It can be seen that, according to the wheel cylinder pressure and the number of wheel speed pulses in one cycle, by accumulating the temperature generated by the unit wheel cylinder pressure and the unit wheel speed pulse work, this embodiment can know the brake with high precision. Plate heating.

In addition, for dynamic braking conditions, if dynamic braking is performed and the vehicle speed in the previous cycle is greater than the current cycle speed, it means that the vehicle is in a braking state, that is, the driver activates the EPB system to achieve vehicle braking. working conditions. At this time, the EPB system controls the left rear brake disc and the right rear brake disc to generate heat by friction with the corresponding friction plates, and then converts part of the kinetic energy of the vehicle into the temperature rise heat of the brake disc, while the left front brake disc and the right front brake disc The moving disc does not play a braking role. Based on this, if dynamic braking is applied and the speed of the previous cycle is greater than the speed of the current cycle, the temperature rise of the brake disc is determined as follows:

In the formula, W ₂ represents the amount of thermal energy converted from kinetic energy, K ₂ represents the conversion coefficient of kinetic energy into heat energy, V ₂ represents the kinetic energy at the vehicle speed of the previous cycle, and V ₁ represents the kinetic energy at the vehicle speed of the current cycle.

The calculation principle of V ₂ and V ₁ can be half of the product of the square of the vehicle speed and the vehicle mass under the corresponding cycle.

Adaptively, if dynamic braking is performed and the vehicle speed in the previous cycle is lower than the vehicle speed in the current cycle, it means that the vehicle is in an accelerating state, that is, the aforementioned driver activates the EPB system and depresses the accelerator pedal. At this time, since the left rear brake disc and the right rear brake disc do not rub against the friction plate, the heating heat of the brake disc is zero.

S230. Determine the cooling of the brake disc according to the cooling relationship of the brake disc with the vehicle speed.

During the driving process of the vehicle, the vehicle speed is the core factor affecting the cooling of the brake disc. The higher the vehicle speed, the greater the cooling rate of the brake disc.

The cooling of the brake discs is determined as follows:

T ₂ =K ₃ ·ΔT

In the formula, _T2 represents the cooling of the brake disc, and _K3 represents the cooling coefficient of the brake disc with the speed of the vehicle.

In addition, ΔT is the difference between the brake disc temperature and the external environment temperature in the last cycle.

S240. Determine the temperature of the brake disc according to the initialization temperature and the temperature rise of the brake disc minus the temperature drop of the brake disc.

To sum up, the embodiment of the present application divides the temperature of the brake disc into initialization temperature, heating up of the brake disc, and cooling down of the brake disc. On the basis of confirming the heating of the moving disc and the cooling of the brake disc in sequence, the determination of the temperature of the brake disc is realized, which effectively reduces the difficulty of confirming the temperature of the brake disc and improves the confirmation of the temperature of the brake disc Accuracy is conducive to the EPB system to perform precise high-temperature re-clamping operations and avoid the risk of vehicle slippage.

M ₁ , K ₂ and K ₃ can all be confirmed through real vehicle calibration, and K ₃ can also be confirmed through the look-up table method. Based on this, as an example, Table 1 is a data table of the vehicle speed and the cooling coefficient of the brake disc with the vehicle speed provided by the embodiment of the present application.

Table I

Vehicle speed/0.1km·h -1	Cooling coefficient of brake disc with vehicle speed
0	14
50	16
200	18
400	twenty one
800	29
1000	30
1200	31

See Table 1, the speed of the vehicle is proportional to the cooling coefficient of the brake disc with the speed of the vehicle, and the cooling coefficient of the brake disc increases with the increase of the speed of the vehicle.

On the basis of the above-mentioned embodiments, the method for confirming the initialization temperature of the brake disc and the method for confirming the temperature of the brake disc when the high-temperature reclamp function is not available will be described below.

Fig. 3 is a flowchart of another method for determining the temperature of the brake disc provided in the embodiment of the present application. As shown in Fig. 3, the method for determining the temperature of the brake disc includes the following steps:

S310. When the high-temperature re-clamping function is available, when the temperature of the brake disc is lower than the temperature of the external environment, the initialization temperature of the brake disc is equal to the temperature of the external environment.

The external ambient temperature may be obtained by measuring any temperature sensor of the vehicle itself, such as a thermocouple temperature sensor and the like. Exemplarily, the operating condition in which the temperature of the brake disc is lower than the ambient temperature may be that the vehicle has just left the cold storage.

When the temperature of the brake disc is lower than the temperature of the external environment, this embodiment increases the temperature of the brake disc from the source by setting the initial temperature of the brake disc to the temperature of the external environment. The contact between the brake disc and the friction plate is closer, which increases the parking force and helps to avoid the risk of the vehicle slipping.

S320. When the temperature of the brake disc is higher than the temperature of the external environment, the initialization temperature of the brake disc is equal to the temperature of the brake disc in the last cycle minus the temperature ΔT that decreases with the rest time.

The method for calculating the temperature drop of temperature ΔT with rest time may be, but not limited to, multiplying temperature ΔT by the temperature drop coefficient of brake disc temperature with rest time.

S330. In non-dynamic braking conditions, the temperature rise of the current brake disc is equal to the temperature generated by the wheel cylinder pressure and wheel speed pulse work, and if dynamic braking is performed and the vehicle speed in the previous cycle is greater than the current cycle speed, the temperature of the brake disc The heating heat is the heat generated by the speed drop kinetic energy; if dynamic braking is performed and the vehicle speed in the previous cycle is lower than the current cycle speed, the heating heat of the brake disc is 0.

S340. Determine the cooling of the brake disc according to the cooling relationship of the brake disc with the vehicle speed.

S350. Determine the temperature of the brake disc according to the initialization temperature and the temperature rise of the brake disc minus the temperature drop of the brake disc.

S360. When the brake disc temperature is greater than the maximum value of the external environment temperature, the brake disc temperature is lower than the minimum value of the external environment temperature, when the brake disc temperature value is wrong or when the brake disc temperature is unreliable, use the preset temperature as the control The temperature of the moving plate.

The preset temperature may be any temperature value, such as 200°C, 300°C, and so on.

The temperature of the brake disc is higher than the maximum value of the external environment temperature, the temperature of the brake disc is lower than the minimum value of the external environment temperature, when the value of the brake disc temperature is wrong, or when the temperature of the brake disc is not credible, it means that the high temperature re-clamping function of the vehicle is not available. At this time, this embodiment also increases the temperature of the brake disc from the source by directly setting the temperature of the brake disc to the preset temperature. When the EPB system performs high-temperature re-clamping operation, the brake disc is in contact with the friction plate. It is more compact, which is conducive to increasing the parking force and avoiding the risk of vehicle slipping.

The embodiment of the present application may, but is not limited to, confirm the temperature rise of the brake disc first, and then confirm the temperature drop of the brake disc. Exemplarily, in the embodiment of the present application, the temperature drop of the brake disc can be confirmed first, and then the temperature rise of the brake disc can be confirmed; or the initialization temperature, temperature rise and temperature drop of the brake disc can be confirmed at the same time.

On the basis of the above embodiments, Fig. 4 is a flow chart of another method for determining the temperature of the brake disc provided in the embodiment of the present application. As shown in Fig. 4, the method for determining the temperature of the brake disc includes the following steps:

S410. Obtain input parameters required for determining the temperature of the brake disc.

The input parameters can be but not limited to the preset temperature, the conversion coefficient of heat energy into temperature rise, the conversion coefficient of kinetic energy into heat energy, whether the high-temperature re-clamping function of the left rear brake disc and right rear brake disc is available, and the external ambient temperature , The temperature drop coefficient of the temperature of the left rear brake disc and the right rear brake disc with the sleep time, the temperature drop coefficient of the temperature of the left rear brake disc and the right rear brake disc with the vehicle speed, the vehicle speed, the left rear wheel and the right rear wheel The wheel speed pulse of the wheel, the wheel cylinder pressure of the left rear wheel and the right rear wheel, and the dynamic braking flags of the left rear wheel and the right rear wheel, etc. Exemplarily, the method for acquiring the above input parameters may be based on existing input parameters or actual vehicle calibration.

S420. When the high-temperature re-clamping function is available, when the temperature of the brake disc is lower than the temperature of the external environment, the initialization temperature of the brake disc is equal to the temperature of the external environment.

S430. When the temperature of the brake disc is higher than the temperature of the external environment, the initialization temperature of the brake disc is equal to the temperature of the brake disc in the last cycle minus the temperature ΔT that decreases with the rest time.

S440. In non-dynamic braking conditions, the temperature rise of the current brake disc is equal to the temperature generated by the wheel cylinder pressure and wheel speed pulse work, and if dynamic braking is performed and the vehicle speed in the previous cycle is greater than the current cycle speed, the temperature of the brake disc The heating heat is the heat generated by the speed drop kinetic energy; if dynamic braking is performed and the vehicle speed in the previous cycle is lower than the current cycle speed, the heating heat of the brake disc is 0.

S450. Determine the temperature drop of the brake disc according to the temperature drop relationship of the brake disc with the vehicle speed.

S460. Determine the temperature of the brake disc according to the initialization temperature and the temperature rise of the brake disc minus the temperature drop of the brake disc.

S470. When the brake disc temperature is greater than the maximum value of the external environment temperature, the brake disc temperature is less than the minimum value of the external environment temperature, when the brake disc temperature value is wrong or when the brake disc temperature is unreliable, use the preset temperature as the control The temperature of the moving plate.

The embodiment of the present application effectively reduces the difficulty of confirming the temperature of the brake disc, improves the accuracy of the confirmation of the temperature of the brake disc, and is beneficial for the EPB system to perform precise high-temperature re-clamping operations and avoid the risk of the vehicle sliding downhill.

In the actual construction process of the brake disc temperature determination method, the software engineer can build the software architecture of the brake disc temperature determination method based on the existing input parameters without performing real vehicle calibration. By confirming the brake disc temperature under different working conditions The initialization temperature of the brake disc, the heating of the brake disc and the cooling of the brake disc are used to verify whether the method of determining the temperature of the brake disc is feasible. After the software engineer confirms that the method of determining the brake disc temperature is feasible, the matching engineer performs real vehicle calibration according to the specific vehicle model to confirm the input parameters such as the conversion coefficient of heat energy converted into temperature rise and the conversion coefficient of kinetic energy into heat energy of the real vehicle, and finally Determine the brake disc temperature determination method for a specific car model.

Fig. 5 is a schematic structural diagram of a device for determining the temperature of a brake disc provided in an embodiment of the present application, and the device may be implemented by means of software and/or hardware. As shown in FIG. 5 , the brake disc temperature determination device provided in this embodiment includes an initialization temperature confirmation module 510 , a temperature rise determination module 520 , a temperature drop determination module 530 and a temperature confirmation module 540 .

The initialization temperature confirmation module 510 is configured to determine the initialization temperature of the brake disc according to the relationship between the brake disc temperature and the ambient temperature in the last cycle when the high temperature re-clamp function is available. The temperature rise determining module 520 is configured to determine the temperature rise of the brake disc according to the wheel speed pulse and the wheel cylinder pressure in non-dynamic braking conditions, or determine the temperature rise of the brake disc according to the vehicle speed in dynamic braking conditions. The temperature drop determination module 530 is configured to determine the temperature drop of the brake disc according to the temperature drop relationship of the brake disc with the vehicle speed. The temperature confirmation module 540 is configured to determine the temperature of the brake disc according to the initialization temperature and the result of subtracting the temperature reduction of the brake disc from the temperature rise of the brake disc.

In the non-dynamic braking condition, the temperature increase determination module 520 is configured to determine that the current temperature increase of the brake disc is equal to the temperature generated by the wheel cylinder pressure and the work done by the wheel speed pulse.

The temperature generated by unit wheel cylinder pressure and unit wheel speed pulse work is determined by the following method:

In the formula, F _x represents the longitudinal force of the wheel, d represents the radius of the caliper piston, μ represents the friction coefficient of the friction plate, re represents the effective radius of the brake disc, R ₀ represents the rolling radius of the wheel, W ₁ represents the unit wheel cylinder pressure and unit The magnitude of the work done by the wheel speed pulse, S represents the braking distance, T ₁ represents the temperature rise of the brake disc, and M ₁ represents the conversion coefficient of heat energy converted into temperature rise.

In dynamic braking conditions, if dynamic braking is performed and the vehicle speed in the last cycle is greater than the current cycle speed, the temperature rise determination module 520 is configured to determine that the heat of the brake disc is the heat generated by the kinetic energy of the speed drop; The vehicle speed in the previous cycle is lower than the vehicle speed in the current cycle, and the temperature rise determination module 520 is configured to determine that the heat of the brake disc is zero.

If dynamic braking is performed and the vehicle speed in the last cycle is greater than the vehicle speed in the current cycle, the temperature rise determination module 520 determines the temperature rise of the brake disc in the following manner:

In the formula, W ₂ represents the amount of thermal energy converted from kinetic energy, K ₂ represents the conversion coefficient of kinetic energy into heat energy, V ₂ represents the kinetic energy at the vehicle speed of the previous cycle, and V ₁ represents the kinetic energy at the vehicle speed of the current cycle.

Also includes a brake disc temperature confirmation module 540, the brake disc temperature confirmation module 540 is set to the brake disc temperature is greater than the maximum value of the external environment temperature, the brake disc temperature is less than the minimum value of the external environment temperature, when the brake disc temperature value False or when the brake disc temperature is not plausible, the preset temperature is used as the brake disc temperature.

When the brake disc temperature is lower than the external environment temperature, the initialization temperature confirmation module 510 is set to determine that the initialization temperature of the brake disc is equal to the external environment temperature; when the brake disc temperature is higher than the external environment temperature, the initialization temperature confirmation module 510 is set to The initialization temperature of the brake disc is determined to be equal to the temperature of the brake disc in the last cycle minus the temperature that the temperature ΔT decreases with the sleep time, where the temperature ΔT is the difference between the temperature of the brake disc in the last cycle and the external environment temperature.

The temperature reduction determination module 530 determines the temperature reduction of the brake disc in the following manner:

T ₂ =K ₃ ·ΔT

In the formula, _T2 represents the cooling of the brake disc, and _K3 represents the cooling coefficient of the brake disc with the speed of the vehicle.

The brake disc temperature determination device provided in the embodiment of the present application, when the high-temperature re-clamp function is available, determines the initialization temperature of the brake disc through the initialization temperature confirmation module according to the relationship between the brake disc temperature and the ambient temperature in the previous cycle; In the non-dynamic braking condition, the temperature rise of the brake disc is determined by the temperature rise determination module according to the wheel speed pulse and the wheel cylinder pressure, or in the dynamic braking condition, the temperature rise of the brake disc is determined by the temperature rise determination module according to the vehicle speed; The temperature drop determination module determines the temperature drop of the brake disc according to the temperature drop relationship of the brake disc with the speed of the vehicle; the temperature confirmation module determines the temperature of the brake disc according to the initialization temperature and the temperature rise of the brake disc minus the temperature drop of the brake disc.

It can be seen that the device divides the temperature of the brake disc into three components, namely, the initialization temperature, the temperature rise of the brake disc, and the temperature drop of the brake disc. The temperature rise and the temperature drop of the brake disc were confirmed in sequence, and finally the temperature of the brake disc was determined. Based on this, the embodiment of the present application can effectively reduce the difficulty of confirming the brake disc temperature and improve the confirmation accuracy of the brake disc temperature, which is beneficial to the EPB system to perform precise high-temperature re-clamping operations and avoid the risk of vehicle slipping.

The embodiment of the present application also provides a vehicle integrated with the device for determining the temperature of the brake disc provided in any embodiment of the present application. The technical principle and the achieved effect are similar and will not be repeated here.

The embodiment of the present application also provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, the method for determining the temperature of the brake disc as provided in any embodiment of the present application is implemented.

The computer storage medium in the embodiments of the present application may use any combination of one or more computer-readable media. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or device, or any combination thereof. Examples (non-exhaustive list) of computer-readable storage media include: electrical connections with one or more conductors, portable computer disks, hard disks, Random Access Memory (RAM), Read Only Memory (Read Only) Memory, ROM), erasable programmable read-only memory (Erasable Programmable Read-Only Memory, EPROM or flash memory), optical fiber, portable compact disk read-only memory (Compact Disc-Read Only Memory, CD-ROM), optical storage device , a magnetic storage device, or any suitable combination of the above. In this document, a computer-readable storage medium may be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

A computer readable signal medium may include a data signal carrying computer readable program code in baseband or as part of a carrier wave. Such propagated data signals may take many forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the foregoing. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device. .

Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wire, optical cable, radio frequency (Radio Frequency, RF), etc., or any suitable combination of the above.

Computer program codes for performing the operations of the embodiments of the present application may be written in one or more programming languages or combinations thereof, the programming languages including object-oriented programming languages—such as Java, Smalltalk, C++, including A conventional procedural programming language - such as "C" or a similar programming language. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In cases involving a remote computer, the remote computer can be connected to the user's computer through any kind of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or it can be connected to an external computer ( For example, use an Internet service provider to connect via the Internet).

Claims (11)

1. A method for determining the temperature of a brake disc, comprising:

   When the high-temperature re-clamp function is available, determine the initialization temperature of the brake disc according to the relationship between the brake disc temperature and the ambient temperature in the last cycle;

   In the case of non-dynamic braking conditions, the temperature rise of the brake disc is determined according to the wheel speed pulse and the wheel cylinder pressure, or in the case of dynamic braking conditions, according to the vehicle speed;

   Determine the cooling of the brake disc according to the cooling relationship of the brake disc with the speed of the vehicle;

   The temperature of the brake disc is determined according to the initialization temperature and the temperature rise of the brake disc minus the temperature drop of the brake disc.
2. The method according to claim 1, wherein said determining the temperature rise of the brake disc according to the wheel speed pulse and the wheel cylinder pressure comprises:

   The temperature rise of the brake disc is equal to the temperature generated by the wheel cylinder pressure and the work done by the wheel speed pulse.
3. The method according to claim 2, wherein the unit of the wheel cylinder pressure and the temperature generated by the unit of the wheel speed pulse work are determined by the following method:

   

   In the formula, F _x represents the longitudinal force of the wheel, d represents the radius of the caliper piston, μ represents the friction coefficient of the friction plate, re represents the effective radius of the brake disc, R ₀ represents the rolling radius of the wheel, and W ₁ represents the The wheel cylinder pressure and the work done by the unit wheel speed pulse, S represents the braking distance, _T1 represents the temperature rise of the brake disc, and _M1 represents the conversion coefficient of heat energy converted into temperature rise.
4. The method according to claim 1, wherein said determining the temperature rise of the brake disc according to the vehicle speed in the case of a dynamic braking condition comprises:

   In the case of dynamic braking and the vehicle speed in the previous cycle is greater than the current cycle speed, the heat of the brake disc heating is the heat generated by the kinetic energy of the speed drop;

   In the case of dynamic braking and the vehicle speed in the previous cycle is lower than the vehicle speed in the current cycle, the heating heat of the brake disc is 0.
5. The method according to claim 4, wherein when dynamic braking is performed and the vehicle speed in the previous cycle is greater than the vehicle speed in the current cycle, the temperature rise of the brake disc is determined by the following method:

   

   In the formula, W ₂ represents the size of heat energy converted from kinetic energy, K ₂ represents the conversion coefficient of kinetic energy into heat energy, V ₂ represents the kinetic energy at the vehicle speed of the previous cycle, V ₁ represents the kinetic energy at the vehicle speed of the current cycle, and T ₁ Indicates the temperature rise of the brake disc.
6. The method of claim 1 further comprising:

   When the temperature of the brake disc is greater than the maximum value of the external environment temperature, the temperature of the brake disc is lower than the minimum value of the external environment temperature, the value of the temperature of the brake disc is wrong, or the temperature of the brake disc is unreliable, the preset temperature is used as the control system. The temperature of the moving plate.
7. The method according to claim 1, wherein said determining the initialization temperature of the brake disc according to the relationship between the temperature of the brake disc in the last cycle and the ambient temperature comprises:

   When the temperature of the brake disc is lower than the temperature of the external environment, the initialization temperature of the brake disc is equal to the temperature of the external environment;

   When the temperature of the brake disc is higher than the temperature of the external environment, the initialization temperature of the brake disc is equal to the temperature of the brake disc in the last cycle minus the temperature ΔT that decreases with the sleep time, wherein the temperature ΔT is the last cycle The difference between the cyclic brake disc temperature and the ambient temperature.
8. The method according to claim 1, wherein the cooling of the brake disc is determined by:

   T ₂ =K ₃ ·ΔT;

   In the formula, T ₂ represents the temperature drop of the brake disc, K ₃ represents the cooling coefficient of the brake disc with the speed of the vehicle, and ΔT is the difference between the temperature of the brake disc in the last cycle and the temperature of the external environment.
9. A device for determining the temperature of a brake disc, comprising:

   The initialization temperature confirmation module is set to determine the initialization temperature of the brake disc according to the relationship between the brake disc temperature and the ambient temperature in the last cycle when the high temperature re-clamp function is available;

   The temperature rise determination module is configured to determine the temperature rise of the brake disc according to the wheel speed pulse and the wheel cylinder pressure in the case of non-dynamic braking conditions, or to determine the temperature rise of the brake disc according to the vehicle speed in the case of dynamic braking conditions. heating up;

   The cooling determination module is configured to determine the cooling of the brake disc according to the cooling relationship of the brake disc with the speed of the vehicle;

   The temperature confirmation module is configured to determine the temperature of the brake disc according to the initialization temperature and the result of the temperature rise of the brake disc minus the temperature drop of the brake disc.
10. A vehicle integrated with the device for determining the brake disc temperature as claimed in claim 9 .
11. A computer-readable storage medium, storing a computer program, and implementing the method for determining the temperature of a brake disc according to any one of claims 1-8 when the program is executed by a processor.

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