Brake disc derusting method based on vehicle braking

Abstract

The invention discloses a brake disc derusting method based on vehicle braking, which comprises the steps that a brake disc derusting mode is set, and after a vehicle enters the brake disc derusting mode, if a braking demand of a user is received, a wheel end caliper braking mode is adopted to meet the braking demand. The method has the advantages that on the premise of not sacrificing a large amount of energy recovery efficiency and ensuring the driving economy, the brake disc can be effectively wiped and derusted through automatic wheel end caliper friction braking, the service life of a brake system is prolonged, and the driving safety of a driver is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automobile brake system control, in particular to a brake disc rust removal method based on vehicle braking. BACKGROUND

[0002] The automobile brake disc is an important component of the entire brake system, and its state will directly affect the braking effect and driving safety. The automobile brake disc is usually made of cast iron. If the automobile is parked in a high-temperature and rainy environment for a long time, the brake disc is prone to oxidation reaction in this environment and is corroded to form rust and other surface foreign matter. Rusty brake disc has a probability of producing squeal or friction sound when braking, which greatly affects the comfort of riding. In addition to the noise problem, the rough surface of the rusty brake disc will accelerate the wear of the brake pad, shorten the service life, and increase the cost of replacing parts. Rust will also reduce the friction coefficient between the brake disc and the friction plate, resulting in a decrease in braking efficiency and an increase in vehicle braking distance.

[0003] The surface of the brake disc that is used frequently can be kept relatively dry, and only a few normal wheel end caliper friction brakes are needed during driving to effectively remove surface foreign matter and reduce the possibility of rust. However, based on the current situation that energy recovery technology is widely used in new energy vehicles, vehicles equipped with this technology use the drive motor as a generator and shield the wheel end caliper friction brake during braking to improve vehicle energy efficiency. This is obviously different from traditional braking by contact friction brake disc deceleration.

[0004] It has become a trend to continuously reduce the proportion of wheel end caliper friction braking to improve the endurance of new energy vehicles through energy recovery technology. Existing energy recovery technology mainly uses motor reverse traction to achieve vehicle braking and deceleration, which will result in less frequency and lower intensity of brake disc friction braking. The brake pad and brake disc cannot be fully rubbed under motor braking, so the removal effect cannot be achieved. In this case, the brake disc of the new energy vehicle is more prone to accumulate rust and other surface foreign matter, especially in coastal areas, which undoubtedly poses a threat to driving safety. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the prior art and provide a brake disc rust removal method based on vehicle braking. By setting a rust removal mode, the rust removal control of the brake disc is realized. After detecting that the rust removal condition is met, the rust removal mode is actively started. In the rust removal mode, the wheel end caliper friction braking method meets the user's braking demand while achieving brake rust removal.

[0006] In order to achieve the above object, the technical scheme adopted by the present application is as follows: a brake disc rust removal method based on vehicle braking, comprising a brake disc rust removal mode, after the vehicle enters the brake disc rust removal mode, if the user's braking demand is received, the wheel end caliper braking mode is adopted to meet the braking demand.

[0007] According to the vehicle use environment data and the vehicle use state data, it is determined whether to automatically enter the rust removal mode or according to the opening state of the vehicle-mounted rust removal function switch, it is determined whether to enter the rust removal mode.

[0008] In the rust removal mode, the vehicle energy recovery function is prohibited to start or when the wheel end caliper braking cannot meet the user's braking force demand, the additional braking force is taken as the energy recovery braking force to control the vehicle to perform energy recovery braking.

[0009] After entering the rust removal mode, the braking times and / or braking intensity of the vehicle after entering the rust removal mode are collected and calculated, when the braking times and / or braking intensity reach the set threshold, the current friction state and the standard friction state are compared, and according to the difference between the two, it is determined whether to end the rust removal mode.

[0010] After entering the rust removal mode, the braking intensity value is calculated based on the wheel end caliper friction braking force and the braking speed, when the braking intensity value reaches the set intensity threshold, the current friction state and the standard friction state are compared.

[0011] The difference between the current friction state and the standard friction state is compared with the difference threshold to determine whether to end the rust removal mode, when the difference is less than the difference threshold, it is determined to end the rust removal mode, wherein the difference threshold is calculated by pre-calibration database.

[0012] According to the vehicle use environment data and the vehicle use state data, it is determined whether to automatically enter the rust removal mode, comprising: after the vehicle is powered on, the last power-off time is read and the time interval between the last power-off time and the current power-on is calculated, and the air humidity information is collected; when the air humidity data is greater than the set humidity threshold and the time interval is greater than the set time threshold, it is determined to enter the rust removal mode.

[0013] According to the vehicle use environment data and the vehicle use state data, it is determined whether to automatically enter the rust removal mode, further comprising: after the vehicle is started, the current weather condition is obtained; if the weather belongs to rainy weather, the air humidity or the wiper working state data is collected, when the air humidity is greater than the set humidity threshold or the wiper working time exceeds the threshold, it is determined to enter the rust removal mode.

[0014] When the air humidity is greater than a set humidity threshold or the wiper working time exceeds a threshold value, the rust removal mode is entered every set period under the current vehicle driving state, and after entering the rust removal mode, the wheel end caliper braking frequency threshold is calculated according to the current precipitation, air humidity and wiper working frequency, and when the braking frequency reaches the wheel end caliper braking frequency threshold, the difference between the current friction state and the standard friction state is compared and it is judged whether to end the rust removal mode.

[0015] According to the vehicle use environment data and the vehicle use state data, it is judged whether to automatically enter the rust removal mode, which further comprises: after the vehicle is powered on, it is judged whether the vehicle is started and run for the first time after the rain, and if so, it is judged to enter the rust removal mode.

[0016] The present application has the advantages that: on the premise of not greatly sacrificing the energy recovery efficiency and ensuring the driving economy, the automatic wheel end caliper friction braking can effectively wipe and remove the rust on the brake disc, prolong the service life of the braking system and ensure the driving safety of the driver. BRIEF DESCRIPTION OF DRAWINGS

[0017] The content expressed by each drawing of the present application and the marks in the drawings are briefly described as follows:

[0018] Figure 1 The rust removal control method flow chart corresponding to the rust removal mode starting mode one of the present application;

[0019] Figure 2 The rust removal control method flow chart corresponding to the rust removal mode starting mode two of the present application;

[0020] Figure 3 The rust removal control method flow chart corresponding to the rust removal mode starting mode three of the present application;

[0021] Figure 4 The rust removal control method flow chart corresponding to the rust removal mode starting mode four of the present application;

[0022] Figure 5 The control method flow chart of the rust removal mode automatic starting and ending of the present application. DETAILED DESCRIPTION

[0023] The specific embodiments of the present application are further described in detail by comparing the drawings and the description of the optimal embodiments.

[0024] The application provides a brake rust removal method of an energy recovery system, which can realize effective wiping and rust removal of a brake disc by automatic wheel end caliper friction braking under the premise of not greatly sacrificing the efficiency of energy recovery and ensuring driving economy, prolongs the service life of the braking system and ensures the driving safety of the driver. The working principle is to automatically determine whether the vehicle needs to switch the brake rust removal mode according to the weather environment and driving mode of the vehicle, when the vehicle performs the brake disc rust removal work, the energy recovery is not performed, the wheel end caliper friction braking force meets the braking demand, and the number of wheel end caliper friction braking is adjusted according to the braking force required by the driver, and meanwhile, the difference between the current friction state and the standard friction state is compared after different rust removal schemes are performed, the brake disc initialization work is ended within the set difference threshold, and the normal energy recovery is performed. The brake disc rust and surface foreign matter problems caused by long-term parking, humid environment, rainy and snowy weather and the like can be effectively solved.

[0025] The brake disc rust removal method based on vehicle braking provided in the scheme is used to solve the problem of brake disc rust caused by the weakening or even non-participation of wheel end caliper braking in braking due to the energy recovery braking of the prior art. A brake disc rust removal mode is arranged in the brake controller ECU, when the vehicle enters the brake disc rust removal mode, if the braking demand of the user is received, the wheel end caliper braking is adopted to meet the braking demand, and at this time, the energy recovery braking is not adopted. By arranging a special mode in the brake controller ECU, the energy recovery braking is prohibited after entering the mode, and only the wheel end caliper is used for braking, so that the purpose of rust removal can be realized on the basis of meeting the user braking.

[0026] In the scheme, the entering and exiting of the rust removal mode is the core, and by arranging the corresponding entering and exiting rust removal mode strategy, the purpose of braking and rust removal can be accurately and reliably achieved. After entering the rust removal mode, the caliper braking is controlled according to the braking demand of the user to meet the user braking force, and after exiting the rust removal mode, the energy recovery braking and / or caliper braking is controlled according to the pre-set braking strategy to meet the braking demand of the user.

[0027] In the embodiment, whether to automatically enter the rust removal mode is judged according to the use environment data and use state data of the vehicle, or whether to enter the rust removal mode is judged according to the opening state of the rust removal function switch on the vehicle. The rust removal mode is automatically entered according to the use environment and use state data of the vehicle, or the brake is manually opened by the user according to the rust removal function switch, realizes the opening of the rust removal mode in two ways of automatic and manual, realizes more accurate and reliable rust removal, meets the dual demands of intelligent brake rust removal and automatic operation of the user intention.

[0028] In the rust removal mode, the vehicle energy recovery function is prohibited to start or when the wheel end caliper brake cannot meet the user's braking force requirement, the additional braking force is controlled as an energy recovery braking force to brake the vehicle. Because the caliper brake is needed to brake the brake disc in the rust removal mode, the user's braking demand needs to be met by the wheel end caliper brake first, so that the rust removal is completed while the braking demand is met. Therefore, the energy recovery braking needs to be prohibited in the rust removal mode, and in some cases, the priority can be set, that is, the priority of the caliper brake in the rust removal mode is set to be greater than that of the energy recovery braking. When the braking force provided by the caliper brake cannot meet the user's braking demand, the additional braking force that cannot be met is allocated to the energy recovery braking, so that the user's braking demand is met as much as possible, and the caliper brake that is used first can also achieve the purpose of braking and rust removal.

[0029] After entering the rust removal mode, the number of braking times and / or the braking intensity of the vehicle after entering the rust removal mode are collected and calculated. When the number of braking times and / or the braking intensity reaches a set threshold value, the current friction state is compared with the standard friction state, and whether the rust removal mode is ended is determined according to the difference between the two. After the rust removal mode is ended, the brake controller ECU controls the caliper brake and / or the energy recovery brake to brake the vehicle according to the preset braking logic to meet the user's braking force demand. After entering the rust removal mode, whether the rust removal mode is ended is determined according to the number of braking times or the braking intensity. When the number of braking times is greater than a certain threshold value, the rust will also be removed. When the braking intensity reaches a certain intensity, the rust will also be removed. Therefore, both the two ways can achieve the determination of the exit of the rust removal mode.

[0030] After entering the rust removal mode, the braking intensity value is calculated based on the wheel end caliper friction braking force and the braking speed. When the braking intensity value reaches a set intensity threshold value, the current friction state is compared with the standard friction state. The difference between the current friction state and the standard friction state is compared with a difference threshold value to determine whether the rust removal mode is ended. When the difference is less than the difference threshold value, it is determined that the rust removal mode is ended, wherein the difference threshold value is calculated by a pre-calibration database.

[0031] The braking intensity is the integral value of the wheel end caliper friction braking force and the braking speed. The pre-calibration braking intensity threshold value is obtained according to a test database. The test database is the braking intensity required by the corresponding difference value to complete the rust removal work in the actual vehicle test.

[0032] The brake disc state can be predicted according to the weather, vehicle environment, etc., and the required braking cumulative times are estimated by the driver's braking force. After the vehicle friction braking force reaches a certain braking intensity, the difference between the current friction state and the standard friction state is compared. After the rust removal, the difference is within the set difference threshold value, and the brake disc rust removal work is ended.

[0033] In a preferred scheme, the vehicle friction braking force reaches a certain braking intensity, which refers to the calculated value between the vehicle wheel end caliper friction braking force and the braking vehicle speed reaching the preset ending threshold. The braking intensity is the integral value of the wheel end caliper friction braking force and the braking vehicle speed.

[0034] The brake disc friction state and the difference threshold are calculated based on the database of the brake disc data and related influencing factors under driving and braking conditions.

[0035] The standard friction state is established according to the design load of the vehicle, the rolling radius of the wheel, the brake parameter calculation theory and the actual pressure distribution model of the vehicle under different conditions.

[0036] The influencing factors of the brake disc friction state include friction coefficient, temperature, material characteristics, etc. Different brake disc friction states will affect the braking effect, so the torque fluctuation during braking can be used to infer the current brake disc friction state.

[0037] During braking, due to uneven friction material, thermal deformation or wear of the brake disc, the braking torque will fluctuate. These fluctuations contain information about the contact pressure distribution. By building a mathematical model and analyzing these fluctuations through a self-learning algorithm, the distribution of contact pressure can be inferred, and the state of the braking system can be evaluated, such as whether there is uneven wear or surface rust or foreign matter. If the deviation between the current friction state and the initial standard exceeds the threshold, the rust removal mode will continue.

[0038] The ending threshold is based on the difference between the current friction state and the standard friction state, and is valued according to the test database. The brake disc friction state database is established based on data statistics, including vehicle speed, deceleration and wheel end caliper friction braking force during driving, as well as vehicle stopping time, cloud environment, air humidity and other external signals.

[0039] The database needs to be established to cover the conventional conditions, with initial braking speed of 20-120kph, deceleration of 0.1g-1g, brake disc temperature of -40℃-300℃, road adhesion coefficient including dry / wet / ice (u=0.8 / 0.5 / 0.15), test vehicle equipped with infrared thermal imager to record temperature, torque sensor and dot matrix pressure film to generate contact pressure cloud map under various conditions. According to the design load of the vehicle, the rolling radius of the wheel, the brake parameter calculation theory, and the pressure distribution under different conditions of the actual vehicle, a large model database is established.

[0040] After entering the rust removal mode, when the driver brakes, the ECU matches the brake disc temperature with the corresponding model according to the current weather environment obtained, loads the preset contact pressure distribution template in the database according to the vehicle speed, deceleration and wheel end caliper friction braking force in the driving process, and compares.

[0041] In this embodiment, multiple ways of entering the rust removal mode are provided, including three automatic entering modes and one manual entering mode, as shown in the scheme of Figures 1-5 The following will be specifically introduced in combination with the drawings as follows:

[0042] As shown in Figure 1 After the vehicle is powered on, the air humidity information is automatically collected and calculated with the time interval since the last power-off. When it is determined that the vehicle has not been started for a long time in a humid environment, the brake ECU actively adjusts the braking mode to wheel end caliper friction braking. The number of times of wheel end caliper friction braking is automatically determined according to the driver's braking force demand. The difference between the current friction state and the standard friction state is compared. When the difference is within the set threshold, the brake disc rust removal operation is completed, and the brake ECU switches the braking mode to motor braking.

[0043] The standard friction state is established according to the designed load of the vehicle, the rolling radius of the wheel, the theoretical braking energy efficiency calculated from the brake parameters, and the actual pressure distribution model of the vehicle under different working conditions. The current friction state is inferred from the torque fluctuation during braking, and the pressure distribution under the standard friction state is compared to infer the current brake disc friction state.

[0044] The torque fluctuation or vehicle vibration during braking is recorded by the automobile self-provided wheel speed sensor and torque sensor. The ECU queries the large model database trained through a large number of tests. Whether the difference threshold is within the set range is compared. If it is determined that the standard friction state is reached, the rust removal mode is exited.

[0045] As shown in Figure 2 After the vehicle is started, the cloud weather is obtained. If the air humidity or the wiper working time exceeds the threshold value when the vehicle is driven and worked in overcast and rainy weather, the braking mode is actively adjusted to wheel end caliper friction braking by the brake ECU every interval during operation. The number of times of wheel end caliper friction braking is determined according to the current precipitation, air humidity and wiper working frequency. When the number of times of wheel end caliper friction braking by the driver meets the determination condition, the difference between the current friction state and the standard friction state is compared. When the difference is within the set threshold, the brake ECU automatically switches the braking mode to motor braking. The brake disc rust removal operation in this cycle is completed.

[0046] As shown in Figure 3As shown in the figure, when the vehicle is started for the first time after rain, the brake ECU actively adjusts the braking mode to wheel-end caliper friction braking, automatically determines the number of wheel-end caliper friction braking according to the driver's braking force demand, compares the difference between the current friction state and the standard friction state, and if the difference is within the set threshold, the rust removal operation is completed and the brake ECU switches the braking mode to motor braking.

[0047] like Figure 4 As shown, after the vehicle is started, the driver can choose to manually turn on the brake disc rust removal function switch. At this time, the brake ECU actively adjusts the braking mode to wheel-end caliper friction braking, automatically determines the number of wheel-end caliper friction braking according to the driver's braking force demand, compares the difference between the current friction state and the standard friction state, and if the difference is within the set threshold, the rust removal operation is completed, and the driver is automatically reminded that the brake disc rust removal is completed and the switch is turned off. The brake ECU switches the braking mode to motor braking.

[0048] This method automatically adjusts the brake disc rust removal strategy based on the external environment. First, humid environments can cause rust on cast iron brake discs. Whether the vehicle is stationary or operating in a humid environment, this condition is considered rusted by the humid environment. The probability and severity of rust are estimated based on air humidity and the time the vehicle has been in the vehicle. The brake ECU automatically controls the braking mode and determines the required number of brake cycles, taking into account the driver's braking force. Secondly, rainy conditions increase the risk of brake disc rust due to rain. If the vehicle is driven in the rain, friction braking with the wheel calipers is applied at intervals based on the duration of the rain. After rain, friction braking with the wheel calipers is applied first, and the cumulative number of brake replacements is determined based on the driver's braking force. Finally, the driver can activate the brake disc rust removal function as needed using the vehicle's soft switch. The system automatically turns off the brake disc rust removal function after the cleaning process is complete, notifying the driver.

[0049] The above method is actively controlled by the brake ECU. The brake ECU determines the braking mode and controls it based on the environmental data obtained from the sensor or the cloud. The specific method flow is as follows: Figure 5 .

[0050] This method takes environmental conditions into consideration, employing different brake disc rust removal methods for humid and rainy conditions. It intelligently adjusts the braking process based on driving conditions to maximize energy recovery efficiency while also removing rust from the brake disc and cleaning surface foreign matter to ensure driving safety. This method resolves the trade-off between brake disc rust removal and energy recovery, achieving greener travel.

[0051] The scheme can refer to the state and environment (air humidity, current and historical weather) of the vehicle, predict the brake disc state, estimate the required brake cumulative times through the driver braking force, compare the gap between the current friction state and the standard friction state, and within the set difference threshold, automatically switch the wheel end caliper friction brake and the motor brake through logical judgment, and realize the rust removal of the brake disc.

[0052] Obviously, the specific implementation of the present application is not limited by the above-mentioned manner, as long as various non-essential improvements are made by adopting the method concept and technical solutions of the present application, which are within the protection scope of the present application.

Claims

1. A method for removing rust from a brake disc based on vehicle braking, characterized in that: It includes a brake disc rust removal mode. After the vehicle enters the brake disc rust removal mode, if the user's braking demand is received, the wheel end caliper braking method is used to meet the braking demand.

2. The method for removing rust from a brake disc based on vehicle braking according to claim 1, characterized in that: Whether to enter the rust removal mode is determined automatically according to the vehicle's usage environment data and vehicle usage status data, or whether to enter the rust removal mode is determined according to the on-state of the vehicle's rust removal function switch.

3. A method for removing rust from a brake disc based on vehicle braking according to claim 1 or 2, characterized in that: In rust removal mode, the vehicle's energy recovery function is prohibited from starting or when the wheel-end caliper brakes cannot meet the user's braking force requirements, the additional braking force is used as energy recovery braking force to control the vehicle to perform energy recovery braking.

4. A method for removing rust from a brake disc based on vehicle braking according to claim 1 or 2, characterized in that: After entering the rust removal mode, the number of braking times and / or braking intensity of the vehicle after entering the rust removal mode are collected and calculated. When the number of braking times and / or braking intensity reaches the set threshold, the current friction state is compared with the standard friction state, and the difference between the two is used to determine whether to end the rust removal mode.

5. The method for removing rust from a brake disc based on vehicle braking according to claim 4, characterized in that: After entering the rust removal mode, the braking strength value is calculated based on the wheel-end caliper friction braking force and the braking vehicle speed. When the braking strength value reaches the set strength threshold, the current friction state is compared with the standard friction state.

6. The method for removing rust from a brake disc based on vehicle braking according to claim 4, characterized in that: The difference between the current friction state and the standard friction state is compared with the difference threshold to determine whether to end the rust removal mode. When the difference is less than the difference threshold, the rust removal mode is determined to be ended, where the difference threshold is calculated through a pre-calibrated database.

7. The method for removing rust from a brake disc based on vehicle braking according to claim 2, characterized in that: Determining whether to automatically enter the rust removal mode based on the vehicle's usage environment data and vehicle usage status data includes: after the vehicle is powered on, reading the last power-off time and calculating the time interval between the last power-off time and the current power-on time, and collecting air humidity information at the same time; when the air humidity data is greater than the set humidity threshold and the time interval is greater than the set time threshold, it is determined to enter the rust removal mode.

8. The method for removing rust from a brake disc based on vehicle braking according to claim 2, characterized in that: Determining whether to automatically enter the rust removal mode based on the vehicle's usage environment data and vehicle usage status data also includes: after the vehicle is started, obtaining the current weather conditions; if the weather is cloudy and rainy, collecting air humidity or wiper working status data, and when the air humidity is greater than the set humidity threshold or the wiper working time exceeds the threshold value, it is determined to enter the rust removal mode.

9. The method for removing rust from a brake disc based on vehicle braking according to claim 8, characterized in that: When the air humidity is greater than the set humidity threshold or the wiper operating time exceeds the threshold value, under the current vehicle driving state, the vehicle enters the rust removal mode once every set period. After entering the rust removal mode, the wheel end caliper braking number threshold is calculated based on the current precipitation, air humidity, and wiper operating frequency. When the braking number reaches the wheel end caliper braking number threshold, the difference between the current friction state and the standard friction state is compared to determine whether to end the rust removal mode.

10. The method for removing rust from a brake disc based on vehicle braking according to claim 2, characterized in that: Determining whether to automatically enter the rust removal mode based on the vehicle's usage environment data and vehicle usage status data also includes: After the vehicle is powered on, it is determined whether the vehicle is started for the first time after rain. If so, it is determined that the rust removal mode is entered at this time.

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