Electronic parking high-temperature re-clamping control method, system, vehicle and storage medium

Abstract

The present invention discloses a high-temperature re-clamping control method, system, vehicle, and storage medium for electronic parking. The method comprises: determining the brake disc temperature T0 at the moment the vehicle is parked and the speed is zero (i.e., immediately after parking); if the vehicle state at the moment the vehicle is parked and the speed is zero meets the activation conditions for the high-temperature re-clamping function, determining and storing the number of re-clamping operations n and the corresponding n re-clamping time intervals based on T and T0; and then controlling the left and right calipers to perform n re-clamping operations at a preset maximum clamping force according to the n re-clamping time intervals. This invention can save energy while ensuring that the vehicle does not roll down a slope.

Description

Technical Field

[0001] The present invention belongs to the field of automobile brake system control, and in particular relates to an electronic parking high-temperature re-clamping control method, system, vehicle and storage medium. Background Art

[0002] Repeated braking while driving can cause the brake discs to overheat. Due to thermal expansion and contraction, the parking brake force may diminish over time. To prevent the vehicle from rolling down a slope, the electronic parking system requires multiple re-clamping cycles to ensure the required parking brake force is maintained.

[0003] There are two main existing re-clamping schemes: the first continuously calculates the brake disc temperature after the user parks the vehicle. Based on the real-time brake disc temperature, it determines whether the re-clamping trigger condition is met. It also calculates whether the temperature drop is sufficient, and if so, re-clamps. The second determines the current actual vehicle braking force by analyzing the relationship between the brake disc temperature and the brake disc thickness deformation, combined with the initial vehicle braking force. During the temperature drop process, when the actual braking force approaches the slope drag force, the re-clamping action is initiated (for example, CN115384464A discloses an electronic parking high-temperature re-clamping control method, device, vehicle, and storage medium). Both schemes continuously calculate or detect the brake disc temperature after parking to confirm whether the vehicle currently requires re-clamping. The electronic parking system wakes up all controllers equipped with NM network management, preventing the entire vehicle from completing sleep mode. Each controller consumes power, posing a risk of power supply failure and high energy consumption. Summary of the Invention

[0004] The object of the present invention is to provide an electronic parking high-temperature re-clamping control method, system, vehicle and storage medium to save electric energy while ensuring that the vehicle does not roll down a slope.

[0005] The electronic parking high-temperature re-clamping control method of the present invention includes:

[0006] Determine the brake disc temperature T0 when the vehicle is parked and the vehicle speed is 0 (i.e., immediately after parking).

[0007] If the vehicle state at the time when the vehicle is parked and the speed is 0 meets the activation conditions of the high-temperature re-clamping function, the number of re-clamping times n and the corresponding n re-clamping time intervals are determined and stored based on T and T0; where T is the ambient temperature at the time when the vehicle is parked and the speed is 0.

[0008] The left caliper and the right caliper are controlled to perform n re-clamping actions according to the n re-clamping time intervals and with a preset maximum clamping force.

[0009] Preferably, the method for determining the number of re-clamping times n and the corresponding n re-clamping time intervals is:

[0010] According to the ambient temperature T when the vehicle is parked and the vehicle speed is 0, the stored brake disc cooling curve group is searched to obtain the brake disc cooling curve corresponding to the ambient temperature T.

[0011] If T0-T thr ≤T1, then n=1 (i.e., one re-clamping action is performed), and the time t1 required for the brake disc temperature to drop from T0 to T0-T1 is found on the brake disc cooling curve, and t1 is used as the re-clamping time interval relative to the current moment (i.e., the moment when the vehicle is parked and the speed is 0). That is, based on the current moment, after waiting for t1 time, one re-clamping action is performed with the preset maximum clamping force.

[0012] If T1<T0-T thr ≤2T1, then n=2 (i.e., performing two re-clamping actions), find the time t1 required for the brake disc temperature to drop from T0 to T0-T1 and the time t2 required for the brake disc temperature to drop from T0 to T0-2T1 on the brake disc cooling curve, and use t1 and t2 as the two re-clamping time intervals relative to the current moment, that is, t1 is used as the first re-clamping time interval relative to the current moment, and t2 is used as the second re-clamping time interval relative to the current moment, which is equivalent to waiting for t1 time on the basis of the current moment and performing one re-clamping action with the preset maximum clamping force, and waiting for t2 time on the basis of the current moment and performing one re-clamping action with the preset maximum clamping force, for a total of two re-clamping actions.

[0013] If T0-T thr >2T1, then n=3 (i.e., three re-clamping actions are performed). The time t1 required for the brake disc temperature to decrease from T0 to T0-T1, the time t2 required for the brake disc temperature to decrease from T0 to T0-2T1, and the time t3 required for the brake disc temperature to decrease from T0 to T0-3T1 are found on the brake disc cooling curve, and t1, t2, and t3 are respectively used as the three re-clamping time intervals relative to the current moment, that is, t1 is used as the first re-clamping time interval relative to the current moment, t2 is used as the second re-clamping time interval relative to the current moment, and t3 is used as the third re-clamping time interval relative to the current moment. This is equivalent to performing one re-clamping action with the preset maximum clamping force after waiting for t1 time at the current moment, performing one re-clamping action with the preset maximum clamping force after waiting for t2 time at the current moment, and performing one re-clamping action with the preset maximum clamping force after waiting for t3 time at the current moment, based on the current moment, for a total of three re-clamping actions.

[0014] Among them, T thr Indicates the preset disk temperature threshold, T1 indicates the preset temperature threshold, T thr≥3T1, the brake disc cooling curve is the corresponding relationship curve between the brake disc temperature and time.

[0015] Preferably, the method for determining the brake disc temperature T0 when the vehicle is parked and the vehicle speed is 0 comprises the following steps:

[0016] S1. Determine whether the brake disc temperature signal is valid. If so, execute S2; otherwise, execute S3.

[0017] S2. Determine whether the brake disc temperature in the previous cycle is less than T. If so, execute S3; otherwise, execute S4. The initial value of the brake disc temperature is equal to the ambient temperature.

[0018] S3, make the brake disc pretreatment temperature T cs Equal to T, then execute S5.

[0019] S4, make the brake disc pretreatment temperature T cs Equal to the brake disc temperature of the previous cycle, then execute S5.

[0020] S5. Calculate the temperature rise of the hydraulic brake disc △T i and dynamic brake disc temperature rise △T j , then execute S6.

[0021] S6. Using the formula: T lim =T cs +△T i +△T j , calculate the estimated brake disc temperature T after braking lim , then execute S7.

[0022] S7. Use the formula: △T fall =k1*(T lim -T), calculate the brake disc temperature drop △T fall , and then execute S8. Wherein, k1 represents the disk temperature cooling coefficient, which is obtained by querying a preset coefficient table according to the vehicle speed. The preset coefficient table is a correspondence table between the vehicle speed and the disk temperature cooling coefficient.

[0023] S8. Using the formula: T end =T lim -△T fall , calculate the final brake disc temperature T end , then execute S9.

[0024] S9, determine whether the final temperature of the brake disc is T end is greater than T, if so, execute S10, otherwise execute S11.

[0025] S10, the final temperature of the brake disc T endThe process ends with the brake disc temperature T0 at the time when the vehicle is parked and the vehicle speed is 0.

[0026] S11. Set T as the brake disc temperature T0 when the vehicle is parked and the vehicle speed is 0, and then end.

[0027] Preferably, the formula is used: ΔT i =k2*F*P, calculate the hydraulic brake disc temperature rise △T i Where k2 represents the preset temperature rise coefficient, F represents the hydraulic pressure, and P represents the number of wheel speed pulses. F and P are obtained from the CAN bus, and the hydraulic pressure F and the number of wheel speed pulses P are sent to the CAN bus by ESP. Using the formula: △T j =k2*(V t-1 2 -V t 2 ), calculate the dynamic brake disc temperature rise △T j ; Among them, V t-1 Indicates the vehicle speed in the previous cycle, V t Indicates the vehicle speed in the current cycle.

[0028] Preferably, if conditions 1a to 1f are met when the vehicle is parked and the speed is 0, it means that the vehicle state at the time of parking and the speed is 0 meets the activation conditions of the high-temperature re-clamping function. Among them, condition 1a is: the vehicle is in a stationary state. Condition 1b is: the power supply of the entire vehicle is normal; condition 1c is: the left caliper and the right caliper are not damaged and are in a clamped state. Condition 1d is: the clamping request signal is valid. Condition 1e is: the left caliper drive motor and the right caliper drive motor are both in an available state. Condition 1f is: the brake disc temperature T0 is greater than the preset disc temperature threshold T thr (i.e. T0-T thr >0).

[0029] Preferably, the preset disk temperature threshold T thr The preset temperature threshold T1 is 100°C.

[0030] The electronic parking high temperature re-clamping control system of the present invention comprises an electronic parking controller which is programmed to execute the steps of the electronic parking high temperature re-clamping control method.

[0031] The vehicle of the present invention includes the above-mentioned electronic parking high-temperature re-clamping control system.

[0032] The storage medium of the present invention stores a computer-readable program therein, and when the computer-readable program is called, the steps of the above-mentioned electronic parking high-temperature re-clamping control method can be executed.

[0033] The present invention has the following effects:

[0034] (1) After the high-temperature re-clamping function activation conditions are met, the number of re-clamping times n and the corresponding n re-clamping time intervals are determined according to the ambient temperature T and the brake disc temperature T0, and stored. Then, n re-clamping actions are performed at the preset maximum clamping force according to the n re-clamping time intervals, thereby ensuring that the vehicle does not roll down the slope.

[0035] (2) When executing the re-clamping action, it is executed n times according to the stored n re-clamping time intervals with the preset maximum clamping force. After the clamping time interval and the number of executions are determined, there is no need to detect and calculate the brake disc temperature in real time. After parking, except for the module that needs to perform the clamping function, other controllers can go into sleep mode, thereby saving energy and reducing the risk of power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Flowchart of the electronic parking high temperature re-clamping control method in this embodiment.

[0037] Figure 2 Flowchart of the method for determining the brake disc temperature T0 when the vehicle is parked and the vehicle speed is 0 in this embodiment.

[0038] Figure 3 Flowchart of the method for determining the number of re-clamping times n and the corresponding n re-clamping time intervals in this embodiment.

[0039] Figure 4 This is a partial brake disc temperature drop curve diagram in the brake disc temperature drop curve group stored in this embodiment. DETAILED DESCRIPTION

[0040] In this embodiment, the electronic parking controller will obtain the required signals from the sensors on the CAN bus or related hard-wired connections, such as ambient temperature, wheel speed, vehicle speed, gear position, hydraulic pressure, wheel speed pulse number, vehicle power supply status signal, left and right caliper status signal, brake disc temperature validity signal, clamping request signal validity signal, and left and right caliper drive motor availability signal.

[0041] like Figure 1 、 Figure 2 As shown, the electronic parking high temperature re-clamping control method in this embodiment includes:

[0042] The first step is to determine the brake disc temperature T0 when the vehicle is parked and the speed is 0, and then execute the second step.

[0043] like Figure 2 As shown in FIG, the method for determining the brake disc temperature T0 when the vehicle is parked and the vehicle speed is 0 specifically includes the following steps:

[0044] S1. Determine whether the brake disc temperature signal is valid. If so, execute S2; otherwise, execute S3.

[0045] S2. Determine whether the brake disc temperature in the previous cycle is less than T. If so, proceed to S3; otherwise, proceed to S4. Where T is the ambient temperature when the vehicle is parked and the speed is zero. The initial value of the brake disc temperature is equal to the ambient temperature.

[0046] S3, make the brake disc pretreatment temperature T cs Equal to T, then execute S5.

[0047] S4, make the brake disc pretreatment temperature T cs Equal to the brake disc temperature of the previous cycle, then execute S5.

[0048] S5. Calculate the temperature rise of the hydraulic brake disc △T i and dynamic brake disc temperature rise △T j , then execute S6. Specifically:

[0049] Using the formula: △T i =k2*F*P, calculate the hydraulic brake disc temperature rise △T i Where k2 represents the preset temperature rise coefficient, F represents the hydraulic pressure, and P represents the number of wheel speed pulses. Using the formula: △T j =k2*(V t-1 2 -V t 2 ), calculate the dynamic brake disc temperature rise △T j ; Among them, V t-1 Indicates the vehicle speed in the previous cycle, V t Indicates the vehicle speed in the current cycle.

[0050] S6. Using the formula: T lim =T cs +△T i +△T j , calculate the estimated brake disc temperature T after braking lim , then execute S7.

[0051] S7. Use the formula: △T fall =k1*(T lim -T), calculate the brake disc temperature drop △T fall , then execute S8; wherein k1 represents the disk temperature cooling coefficient, k1 is obtained by querying a preset coefficient table according to the vehicle speed (in the current cycle), and the preset coefficient table is a correspondence table between the vehicle speed and the disk temperature cooling coefficient (obtained through calibration).

[0052] S8. Using the formula: T end =T lim-△T fall , calculate the final brake disc temperature T end , then execute S9.

[0053] S9, determine whether the final temperature of the brake disc is T end is greater than T, if so, execute S10, otherwise execute S11.

[0054] S10, the final temperature of the brake disc T end The process ends with the brake disc temperature T0 at the time when the vehicle is parked and the vehicle speed is 0.

[0055] S11. Set T as the brake disc temperature T0 when the vehicle is parked and the vehicle speed is 0, and then end.

[0056] The second step is to determine whether the vehicle state at the moment of parking and vehicle speed being 0 satisfies the activation condition of the high-temperature re-clamping function. If so, execute the third step, otherwise end.

[0057] If conditions 1a to 1f are met when the vehicle is parked and the speed is 0, it means that the vehicle state at the time of parking and the speed is 0 meets the activation conditions of the high-temperature re-clamping function. Otherwise, it means that the vehicle state at the time of parking and the speed is 0 does not meet the activation conditions of the high-temperature re-clamping function. Among them, condition 1a is: the vehicle is in a stationary state. Condition 1b is: the power supply of the entire vehicle is normal; condition 1c is: the left caliper and the right caliper are not damaged and are in a clamped state. Condition 1d is: the clamping request signal is valid. Condition 1e is: the left caliper drive motor and the right caliper drive motor are both in an available state. Condition 1f is: the brake disc temperature T0 is greater than the preset disc temperature threshold T thr (i.e. T0-T thr >0).

[0058] Step 3: According to T and T0, determine the number of re-clamping times n and the corresponding n re-clamping time intervals, store them, and then execute step 4.

[0059] like Figure 3 As shown, the method for determining the number of re-clamping times n and the corresponding n re-clamping time intervals is:

[0060] S21, according to T, search the stored brake disc cooling curve group (see part of Figure 4 ), obtain the brake disc cooling curve corresponding to T, and then execute S22. The brake disc cooling curve group consists of multiple brake disc cooling curves, and one ambient temperature range corresponds to one brake disc cooling curve (for example Figure 4The three ambient temperature ranges in the figure (-20°C to -16°C, 23°C to 27°C, and 40°C to 44°C) correspond to three brake disc cooling curves, respectively. First, find the ambient temperature range to which T belongs. Then, use the brake disc cooling curve corresponding to that ambient temperature range as the brake disc cooling curve corresponding to T. The brake disc cooling curve is a curve (obtained through calibration) that shows the relationship between brake disc temperature and time.

[0061] S22, determine whether T0-T thr ≤T1, if yes, execute S23, otherwise execute S24.

[0062] S23, set n = 1 (i.e., perform one re-clamping action), find the time t1 required for the brake disc temperature to drop from T0 to T0-T1 on the brake disc cooling curve corresponding to T, and use t1 as the re-clamping time interval relative to the current moment (i.e., when the vehicle is parked and the speed is 0). That is, based on the current moment, wait for t1 time before performing one re-clamping action. Where, T thr Indicates the preset disk temperature threshold. In this embodiment, T thr =300°C, T1 represents a preset temperature threshold, and in this embodiment, T1=100°C.

[0063] S24, determine whether T1 < T0-T thr ≤2T1, if yes, execute S25, otherwise (i.e. T0-T thr >2T1) execute S26.

[0064] S25. Set n=2 (i.e., perform two re-clamping actions), and find the time t1 required for the brake disc temperature to drop from T0 to T0-T1 and the time t2 required for the brake disc temperature to drop from T0 to T0-2T1 on the brake disc cooling curve corresponding to T, and use t1 and t2 as the two re-clamping time intervals relative to the current moment, that is, use t1 as the first re-clamping time interval relative to the current moment, and use t2 as the second re-clamping time interval relative to the current moment. This is equivalent to executing one re-clamping action after waiting for t1 time based on the current moment, and executing one re-clamping action after waiting for t2 time based on the current moment, and executing two re-clamping actions in total.

[0065] S26. Set n=3 (i.e., perform three re-clamping actions). On the brake disc cooling curve corresponding to T, find the time t1 required for the brake disc temperature to drop from T0 to T0-T1, the time t2 required for the brake disc temperature to drop from T0 to T0-2T1, and the time t3 required for the brake disc temperature to drop from T0 to T0-3T1. Use t1, t2, and t3 as the three re-clamping time intervals relative to the current moment, that is, use t1 as the first re-clamping time interval relative to the current moment, use t2 as the second re-clamping time interval relative to the current moment, and use t3 as the third re-clamping time interval relative to the current moment. This is equivalent to executing one re-clamping action after waiting for t1 time at the current moment, executing one re-clamping action after waiting for t2 time at the current moment, and executing one re-clamping action after waiting for t3 time at the current moment, for a total of three re-clamping actions.

[0066] Step 4: Control the left and right calipers to re-clamp n times at a preset maximum clamping force, following n re-clamping intervals, and then terminate. The preset maximum clamping force is the maximum clamping force required to ensure the vehicle does not roll when parked on a slope, after confirming the brake type and load conditions. This is determined through actual vehicle calibration.

[0067] When executing the re-clamping action, it is executed n times according to the stored n re-clamping time intervals with the preset maximum clamping force. After the clamping time interval and the number of executions are determined, there is no need to detect and calculate the brake disc temperature in real time. After parking, except for the module that executes the clamping function, other controllers can go into sleep mode, thereby saving energy and reducing the risk of power supply.

[0068] The electronic parking high-temperature re-clamping control system in this embodiment includes an electronic parking controller, which is programmed to execute the steps of the above-mentioned electronic parking high-temperature re-clamping control method.

[0069] This embodiment also provides a vehicle, which includes the above-mentioned electronic parking high-temperature re-clamping control system.

[0070] This embodiment further provides a storage medium storing a computer-readable program. When the computer-readable program is called, the steps of the above-mentioned electronic parking high-temperature re-clamping control method can be executed.

Claims

1. A high temperature re-clamping control method for an electronic parking brake, characterized in that: include: Determine the brake disc temperature T0 when the vehicle is parked and the speed is 0; If the vehicle state at the time of parking and the vehicle speed being 0 satisfies the activation condition of the high-temperature re-clamping function, the number of re-clamping times n and the corresponding n re-clamping time intervals are determined and stored according to T and T0; Controlling the left caliper and the right caliper to perform n re-clamping actions at the preset maximum clamping force according to the n re-clamping time intervals; The method for determining the number of re-clamping times n and the corresponding n re-clamping time intervals is as follows: According to T, search the stored brake disc cooling curve group to obtain the brake disc cooling curve corresponding to T; If T0-T thr ≤T1, then n=1, find the time t1 required for the brake disc temperature to drop from T0 to T0-T1 on the brake disc cooling curve, and use t1 as the re-clamping time interval relative to the current moment; If T1<T0-T thr ≤2T1, then n=2, find the time t1 required for the brake disc temperature to drop from T0 to T0-T1 and the time t2 required for the brake disc temperature to drop from T0 to T0-2T1 on the brake disc cooling curve, and use t1 and t2 as the two re-clamping time intervals relative to the current moment respectively; If T0-T thr >2T1, then n=3, find the time t1 required for the brake disc temperature to drop from T0 to T0-T1, the time t2 required for the brake disc temperature to drop from T0 to T0-2T1, and the time t3 required for the brake disc temperature to drop from T0 to T0-3T1 on the brake disc cooling curve, and use t1, t2, and t3 as the three re-clamping time intervals relative to the current moment respectively; Where T is the ambient temperature when the vehicle is parked and the speed is 0, T thr Indicates the preset disk temperature threshold, T1 indicates the preset temperature threshold, T thr ≥3T1, the brake disc cooling curve is the corresponding relationship curve between the brake disc temperature and time.

2. The electronic parking high temperature re-clamping control method according to claim 1, characterized in that: The method for determining the brake disc temperature T0 when the vehicle is parked and the vehicle speed is 0 includes: S1: Determine whether the brake disc temperature signal is valid. If so, execute S2; otherwise, execute S3. S2. Determine whether the brake disc temperature in the previous cycle is less than T. If so, execute S3; otherwise, execute S4. S3, make the brake disc pretreatment temperature T cs Equal to T, then execute S5; S4, make the brake disc pretreatment temperature T cs Equal to the brake disc temperature of the previous cycle, then execute S5; S5. Calculate the temperature rise of the hydraulic brake disc △T i and dynamic brake disc temperature rise △T j , then execute S6; S6. Using the formula: T lim =T cs +△T i +△T j , calculate the estimated brake disc temperature T after braking lim , then execute S7; S7. Use the formula: △T fall =k1*(T lim -T), calculate the brake disc temperature drop △T fall , then execute S8; wherein k1 represents the disk temperature cooling coefficient, k1 is obtained by querying a preset coefficient table according to the vehicle speed, and the preset coefficient table is a correspondence table between the vehicle speed and the disk temperature cooling coefficient; S8. Using the formula: T end =T lim -△T fall , calculate the final brake disc temperature T end , then execute S9; S9, determine whether the final temperature of the brake disc is T end is greater than T, if so, execute S10, otherwise execute S11; S10, the final temperature of the brake disc T end As the brake disc temperature T0 when the vehicle is parked and the vehicle speed is 0, then end; S11. Set T as the brake disc temperature T0 when the vehicle is parked and the vehicle speed is 0, and then end.

3. The electronic parking high temperature re-clamping control method according to claim 2, characterized in that: Using the formula: △T i =k2*F*P, calculate the hydraulic brake disc temperature rise △T i ; Wherein, k2 represents the preset temperature rise coefficient, F represents the hydraulic pressure, and P represents the number of wheel speed pulses; Using the formula: △T j =k2*(V t-1 2 -V t 2 ), calculate the dynamic brake disc temperature rise △T j ; Among them, V t-1 Indicates the vehicle speed in the previous cycle, V t Indicates the vehicle speed in the current cycle.

4. The electronic parking high temperature re-clamping control method according to any one of claims 1 to 3, characterized in that: If the vehicle is parked and the speed is 0 and conditions 1a to 1f are met, it means that the vehicle state at the time of parking and the speed is 0 meets the activation conditions of the high-temperature re-clamping function; Condition 1a is: the vehicle is stationary; Condition 1b: The vehicle power supply is normal; Condition 1c: The left and right calipers are undamaged and both are in the clamped state; Condition 1d is: the clamping request signal is valid; Condition 1e: both the left caliper drive motor and the right caliper drive motor are in an available state; Condition 1f is: the brake disc temperature T0 is greater than the preset disc temperature threshold T thr .

5. The electronic parking high temperature re-clamping control method according to any one of claims 1 to 3, characterized in that: The preset disk temperature threshold T thr is 300℃.

6. The electronic parking high temperature re-clamping control method according to claim 5, characterized in that: The preset temperature threshold T1 is 100°C.

7. An electronic parking high-temperature re-clamping control system, including an electronic parking controller, characterized in that: The electronic parking controller is programmed to execute the steps of the electronic parking high temperature re-clamping control method according to any one of claims 1 to 6.

8. A vehicle, characterized in that: It includes the electronic parking high temperature re-clamping control system as claimed in claim 7.

9. A storage medium, characterized in that: A computer-readable program is stored therein, and when the computer-readable program is called, the steps of the electronic parking high-temperature re-clamping control method according to any one of claims 1 to 6 can be executed.

Images