An optimization method for electronically controlled hydraulic braking of new energy light passenger vehicles

Abstract

The present invention provides a method for optimizing electronically controlled hydraulic braking of new energy light commercial vehicles. The method monitors the brake pedal position through a high-precision sensor and corrects the signal in combination with the vehicle speed and load information, identifies the driver's braking intention and calculates the required braking force, utilizes electric motor braking to recover energy, dynamically adjusts the regenerative braking power according to the braking force demand, and smoothly transitions to hydraulic braking when necessary. The method shortens the braking response time and reduces the braking distance through rapid pressure building technology and optimized design. The method intelligently adjusts the braking strategy according to different road conditions. For example, on slippery roads, electric motor braking is reduced to avoid skidding, and on long downhill sections, electric motor braking is increased to reduce the risk of thermal attenuation, thereby achieving the dual goals of improving braking performance and efficient energy utilization.

Description

Technical Field

[0001] The present invention relates to the field of automobile braking technology, and in particular to a method for optimizing electronically controlled hydraulic braking of a new energy light passenger vehicle. Background Art

[0002] With the development of new energy vehicle technology, the requirements for braking systems are getting higher and higher. Traditional hydraulic braking systems face new challenges on new energy buses, such as low energy recovery efficiency, slow braking response, and long braking distance. At the same time, since new energy buses are usually equipped with electric motors as drive devices, how to effectively use electric motors for energy recovery and improve overall braking performance has become one of the key technical issues.

[0003] Existing braking systems often fail to fully utilize the regenerative braking function of electric motors, resulting in a large amount of kinetic energy being lost in the form of heat energy during braking, reducing energy utilization efficiency. The response time of traditional hydraulic braking systems is relatively long, especially when emergency braking is required, which may lead to an increase in braking distance, thereby reducing driving safety. Under different road conditions, the performance of the braking system varies significantly, especially the efficiency and stability of electric motor regenerative braking will be greatly affected. During long-term or continuous braking, traditional friction braking systems are prone to overheating, resulting in reduced braking efficiency and increased safety hazards.

[0004] At present, many braking systems are unable to flexibly adjust the braking force distribution according to the driver's intentions and the actual working conditions of the vehicle, making it difficult to achieve the best braking effect. In the process of switching from electric motor braking to hydraulic braking, sudden changes in braking effect are prone to occur, affecting driving comfort and safety. Summary of the invention

[0005] The purpose of the present invention is to provide a method for optimizing electronically controlled hydraulic braking of a new energy light commercial vehicle.

[0006] The problem to be solved by the present invention is: to solve the braking efficiency problem of new energy light commercial vehicles under different driving conditions, and to achieve efficient energy recovery, shorten the braking distance, reduce the risk of thermal attenuation, and improve driving safety and stability under slippery and long downhill complex road conditions by optimizing the electronically controlled hydraulic braking system.

[0007] A method for optimizing the electronically controlled hydraulic brake of a new energy light passenger vehicle, the technical solution adopted is as follows:

[0008] S1: Brake pedal position signal acquisition, obtain information about the degree of the driver's brake pedal depression, use a high-precision brake pedal position sensor to monitor the position change of the brake pedal in real time, and convert it into an electrical signal, detect the converted electrical signal and correct the signal according to the vehicle speed and load;

[0009] S2: Braking intention recognition and braking force calculation, recognize the driver's braking intention according to the pedal position signal, and calculate the required braking force based on the vehicle speed and load, calculate the required braking force based on the pedal position signal, match the driver's braking needs, evaluate the vehicle state speed and load at the initial braking stage, and determine the initial working mode of the motor and engine;

[0010] S3: Smooth intervention of electric motor braking energy recovery and electronically controlled hydraulic braking. When the driver's braking intention is detected at the initial stage of braking, energy recovery is first performed through the electric motor. The regenerative braking power of the electric motor is dynamically adjusted according to the required braking force. When the electric motor braking cannot meet the braking force requirement, a smooth transition to hydraulic braking is performed. The solenoid valve in the electronically controlled hydraulic braking system is used to dynamically adjust the hydraulic pressure according to the braking force requirement. The rapid pressure building technology is used to build up a pressure of 10MPa within 200ms. Braking decoupling is achieved under specific conditions, that is, only the electric motor is used for braking at a deceleration of 0.2g. The vehicle state and braking force requirement are judged. At low deceleration, only the electric motor is used for braking. At high deceleration, the electronically controlled hydraulic braking system automatically intervenes to smoothly transition the braking response between electric motor braking and hydraulic braking.

[0011] S4: Braking response optimization, optimizes the response time of the entire braking system, optimizes the design of the hydraulic pump and accumulator, improves the response speed of the solenoid valve, and adopts fast pressure building technology to achieve fast response and smooth transition between the power system and the braking system in emergency braking, thereby reducing the braking distance;

[0012] S5: Adjusts braking strategy according to different road conditions. On slippery roads, reduces the use of electric motor braking and increases the proportion of hydraulic braking. On long downhill sections, increases electric motor braking to reduce the risk of thermal attenuation of the friction brake system. Intelligently adjusts the output of the brake system according to road conditions to adapt to changing driving conditions.

[0013] Furthermore, the S1 detects the converted electrical signal and corrects the signal according to the vehicle speed and load, including:

[0014] S11: Use a low-pass filter to remove high-frequency noise in the signal, and use an amplifier to amplify the weak signal output by the sensor;

[0015] S12: Compare the data of the vehicle speed sensor to see whether the logic of the converted electrical signal change is consistent with the vehicle speed change, and observe whether there is any signal offset;

[0016] S13: reducing the gain of the brake pedal position signal when driving at low speed and with light load, and increasing the gain of the brake pedal position signal when driving at high speed and with heavy load, and establishing a three-dimensional lookup table including vehicle speed, load and corresponding gain coefficient.

[0017] Furthermore, the step S2 calculates the required braking force based on the pedal position signal and determines the initial working mode of the motor and the engine, including:

[0018] S21: Identify the driver's braking intention based on the rate of change and absolute position of the pedal position, and calculate the required target deceleration based on the vehicle's current speed and load status ;

[0019] S22: Calculate the effective mass of the vehicle , ,in is the unloaded mass, is the load mass;

[0020] S23: Calculate the required target deceleration , , , ,in and is the deceleration constant, which indicates the deceleration change per unit pedal position signal. The brake pedal position sensor outputs a signal ranging from 0 to 1, where 0 indicates that the brake pedal is not depressed and 1 indicates that the brake pedal is fully depressed. is the speed influence coefficient, which indicates the influence of speed on the required deceleration. is the load influence factor, which indicates the effect of the load on the required deceleration, is the current speed of the vehicle;

[0021] S24: Calculate the required braking force ;

[0022] S25: Setting the braking force threshold determines the initial working mode of the motor and the engine, and the minimum braking force requirement threshold , maximum braking force requirement threshold ,when , only the regenerative braking of the motor is adopted, when The regenerative braking of the motor and the hydraulic braking system work together. , the regenerative braking of the electric motor works together with the hydraulic braking system and activates the hydraulic braking system in advance.

[0023] Furthermore, judging the vehicle state and braking force requirement in S3 and smoothly transitioning the braking response between electric motor braking and hydraulic braking includes:

[0024] S31: Initial low deceleration stage, only motor braking is used to dynamically adjust the motor braking power. ,in is the motor braking deceleration, The maximum deceleration of the motor brake;

[0025] S32: When the electric motor braking cannot meet the braking force requirement, the electronically controlled hydraulic braking system is started, and the solenoid valve is used to dynamically adjust the hydraulic pressure according to the braking force requirement. ,in is the hydraulic brake deceleration;

[0026] S33: Smooth transition between motor braking and hydraulic braking. When the required deceleration is greater than the maximum deceleration of motor braking, hydraulic braking is gradually started. ,in is the maximum deceleration of hydraulic brake, It is the smooth transition point between electric motor braking and hydraulic braking.

[0027] Furthermore, the output of the braking system is intelligently adjusted according to the road condition characteristics in S5 to adapt to the changing driving conditions, including:

[0028] S51: using a wheel speed sensor and a lateral acceleration sensor to identify road condition characteristics and determine whether the road section the vehicle is traveling on is a slippery road or a long downhill section;

[0029] S52: For slippery roads, the electric motor braking power is reduced to the minimum effective value, the hydraulic brake pressure is dynamically adjusted through the electronic control unit, the ABS system monitors the wheel speed, adjusts the hydraulic pressure, and calculates the slip rate based on the wheel speed and vehicle speed. , ,in is the vehicle speed, For wheel speed, set the slip ratio The threshold is 15%. When the slip rate exceeds 15%, the hydraulic pressure is reduced through the solenoid valve. When the slip rate returns to below 15%, the hydraulic pressure is increased through the solenoid valve and the process is repeated.

[0030] S53: For long downhill sections, the motor braking power is increased to maintain a constant speed while descending. The motor braking power is dynamically adjusted by the electronic control unit according to the changes in slope and speed. , ,in is the vehicle speed, is the slope, monitors the temperature of the brake system, sets the temperature threshold, and adjusts the motor braking power. When the temperature of the brake system does not exceed the threshold, the motor braking power is When the temperature of the braking system exceeds the threshold, the motor braking power is , ,in is the current temperature of the brake system, is the temperature threshold, is the temperature-dependent power reduction factor.

[0031] The beneficial effects of the present invention are as follows: by accurately identifying the driver's braking intention and quickly calculating the required braking force, the braking response is ensured to be rapid and accurate, thereby shortening the braking distance and improving driving safety; by utilizing the rapid pressure building technology of the electronically controlled hydraulic braking system, sufficient hydraulic pressure can be achieved in a very short time, ensuring the instant response of the braking system in an emergency; reducing the use of electric motor braking on slippery roads, increasing the proportion of hydraulic braking, effectively preventing wheel locking, and improving the stability and controllability of the vehicle;

[0032] Intelligently adjust the output of the braking system according to different road conditions, so that the vehicle can maintain good braking performance under various complex conditions. Increasing the use of electric motor braking on long downhill sections helps reduce the risk of thermal attenuation of the friction braking system and extend the service life of the braking system.

[0033] Prioritizing the use of electric motor braking for energy recovery not only reduces energy consumption, but also converts the energy generated during braking into electrical energy for storage and reuse, improving the overall energy utilization efficiency. Through sophisticated control strategies, a smooth transition between electric motor braking and hydraulic braking is achieved, avoiding energy waste and further improving energy utilization.

[0034] By accurately correcting the brake pedal position signal and comprehensively considering vehicle speed and load factors, a more linear braking feel can be provided, improving the driver's operating experience. The smooth braking transition reduces the impact during braking and makes the ride more comfortable. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The figure is a flow chart of an optimization method for electronically controlled hydraulic braking of a new energy light commercial vehicle. DETAILED DESCRIPTION

[0036] The present invention is further clearly and completely described below, but the protection scope of the present invention is not limited thereto.

[0037] A method for optimizing the electronically controlled hydraulic brake of a new energy light passenger vehicle, the technical solution adopted is as follows:

[0038] S1: Brake pedal position signal acquisition, obtain information about the degree of the driver's brake pedal depression, use a high-precision brake pedal position sensor to monitor the position change of the brake pedal in real time, and convert it into an electrical signal, detect the converted electrical signal and correct the signal according to the vehicle speed and load;

[0039] S2: Braking intention recognition and braking force calculation, recognize the driver's braking intention according to the pedal position signal, and calculate the required braking force based on the vehicle speed and load, calculate the required braking force based on the pedal position signal, match the driver's braking needs, evaluate the vehicle state speed and load at the initial braking stage, and determine the initial working mode of the motor and engine;

[0040] S3: Smooth intervention of electric motor braking energy recovery and electronically controlled hydraulic braking. When the driver's braking intention is detected at the initial stage of braking, energy recovery is first performed through the electric motor. The regenerative braking power of the electric motor is dynamically adjusted according to the required braking force. When the electric motor braking cannot meet the braking force requirement, a smooth transition to hydraulic braking is performed. The solenoid valve in the electronically controlled hydraulic braking system is used to dynamically adjust the hydraulic pressure according to the braking force requirement. The rapid pressure building technology is used to build up a pressure of 10MPa within 200ms. Braking decoupling is achieved under specific conditions, that is, only the electric motor is used for braking at a deceleration of 0.2g. The vehicle state and braking force requirement are judged. At low deceleration, only the electric motor is used for braking. At high deceleration, the electronically controlled hydraulic braking system automatically intervenes to smoothly transition the braking response between electric motor braking and hydraulic braking.

[0041] S4: Braking response optimization, optimizes the response time of the entire braking system, optimizes the design of the hydraulic pump and accumulator, improves the response speed of the solenoid valve, and adopts fast pressure building technology to achieve fast response and smooth transition between the power system and the braking system in emergency braking, thereby reducing the braking distance;

[0042] S5: Adjusts braking strategy according to different road conditions. On slippery roads, reduces the use of electric motor braking and increases the proportion of hydraulic braking. On long downhill sections, increases electric motor braking to reduce the risk of thermal attenuation of the friction brake system. Intelligently adjusts the output of the brake system according to road conditions to adapt to changing driving conditions.

[0043] Furthermore, the S1 detects the converted electrical signal and corrects the signal according to the vehicle speed and load, including:

[0044] S11: Use a low-pass filter to remove high-frequency noise in the signal, and use an amplifier to amplify the weak signal output by the sensor;

[0045] S12: Compare the data of the vehicle speed sensor to see whether the logic of the converted electrical signal change is consistent with the vehicle speed change, and observe whether there is any signal offset;

[0046] S13: reducing the gain of the brake pedal position signal when driving at low speed and with light load, and increasing the gain of the brake pedal position signal when driving at high speed and with heavy load, and establishing a three-dimensional lookup table including vehicle speed, load and corresponding gain coefficient.

[0047] Furthermore, the step S2 calculates the required braking force based on the pedal position signal and determines the initial working mode of the motor and the engine, including:

[0048] S21: Identify the driver's braking intention based on the rate of change and absolute position of the pedal position, and calculate the required target deceleration based on the vehicle's current speed and load status ;

[0049] S22: Calculate the effective mass of the vehicle , ,in is the unloaded mass, is the load mass;

[0050] S23: Calculate the required target deceleration , , , ,in and is the deceleration constant, which indicates the deceleration change per unit pedal position signal. The brake pedal position sensor outputs a signal ranging from 0 to 1, where 0 indicates that the brake pedal is not depressed and 1 indicates that the brake pedal is fully depressed. is the speed influence coefficient, which indicates the influence of speed on the required deceleration. is the load influence factor, which indicates the effect of the load on the required deceleration, is the current speed of the vehicle;

[0051] S24: Calculate the required braking force ;

[0052] S25: Setting the braking force threshold determines the initial working mode of the motor and the engine, and the minimum braking force requirement threshold , maximum braking force requirement threshold ,when , only the regenerative braking of the motor is adopted, when The regenerative braking of the motor and the hydraulic braking system work together. , the regenerative braking of the electric motor works together with the hydraulic braking system and activates the hydraulic braking system in advance.

[0053] Furthermore, judging the vehicle state and braking force requirement in S3 and smoothly transitioning the braking response between electric motor braking and hydraulic braking includes:

[0054] S31: Initial low deceleration stage, only motor braking is used to dynamically adjust the motor braking power. ,in is the motor braking deceleration, The maximum deceleration of the motor brake;

[0055] S32: When the electric motor braking cannot meet the braking force requirement, the electronically controlled hydraulic braking system is started, and the solenoid valve is used to dynamically adjust the hydraulic pressure according to the braking force requirement. ,in is the hydraulic brake deceleration;

[0056] S33: Smooth transition between motor braking and hydraulic braking. When the required deceleration is greater than the maximum deceleration of motor braking, hydraulic braking is gradually started. ,in is the maximum deceleration of hydraulic brake, It is the smooth transition point between electric motor braking and hydraulic braking.

[0057] Furthermore, the output of the braking system is intelligently adjusted according to the road condition characteristics in S5 to adapt to the changing driving conditions, including:

[0058] S51: using a wheel speed sensor and a lateral acceleration sensor to identify road condition characteristics and determine whether the road section the vehicle is traveling on is a slippery road or a long downhill section;

[0059] S52: For slippery roads, the electric motor braking power is reduced to the minimum effective value, the hydraulic brake pressure is dynamically adjusted through the electronic control unit, the ABS system monitors the wheel speed, adjusts the hydraulic pressure, and calculates the slip rate based on the wheel speed and vehicle speed. , ,in is the vehicle speed, For wheel speed, set the slip ratio The threshold is 15%. When the slip rate exceeds 15%, the hydraulic pressure is reduced through the solenoid valve. When the slip rate returns to below 15%, the hydraulic pressure is increased through the solenoid valve and the process is repeated.

[0060] S53: For long downhill sections, the motor braking power is increased to maintain a constant speed while descending. The motor braking power is dynamically adjusted by the electronic control unit according to the changes in slope and speed. , ,in is the vehicle speed, is the slope, monitors the temperature of the brake system, sets the temperature threshold, and adjusts the motor braking power. When the temperature of the brake system does not exceed the threshold, the motor braking power is When the temperature of the braking system exceeds the threshold, the motor braking power is , ,in is the current temperature of the brake system, is the temperature threshold, is the temperature-dependent power reduction factor.

[0061] The present invention provides a method for optimizing electronically controlled hydraulic braking of new energy light commercial vehicles. The method monitors the brake pedal position through a high-precision sensor and corrects the signal in combination with the vehicle speed and load information, identifies the driver's braking intention and calculates the required braking force, utilizes electric motor braking to recover energy, dynamically adjusts the regenerative braking power according to the braking force demand, and smoothly transitions to hydraulic braking when necessary. The method shortens the braking response time and reduces the braking distance through rapid pressure building technology and optimized design. The method intelligently adjusts the braking strategy according to different road conditions. For example, on slippery roads, electric motor braking is reduced to avoid skidding, and on long downhill sections, electric motor braking is increased to reduce the risk of thermal attenuation, thereby achieving the dual goals of improving braking performance and efficient energy utilization.

Claims

1. A method for optimizing the electronically controlled hydraulic brake of a new energy light passenger vehicle, the technical solution adopted is as follows: S1: Brake pedal position signal acquisition, obtain information about the degree of the driver's brake pedal depression, use a high-precision brake pedal position sensor to monitor the position change of the brake pedal in real time, and convert it into an electrical signal, detect the converted electrical signal and correct the signal according to the vehicle speed and load; S2: Braking intention recognition and braking force calculation, recognize the driver's braking intention according to the pedal position signal, and calculate the required braking force based on the vehicle speed and load, calculate the required braking force based on the pedal position signal, match the driver's braking needs, evaluate the vehicle state speed and load at the initial braking stage, and determine the initial working mode of the motor and engine; S21: Identify the driver's braking intention based on the rate of change and absolute position of the pedal position, and calculate the required target deceleration based on the vehicle's current speed and load status ; S22: Calculate the effective mass of the vehicle , ,in is the unloaded mass, is the load mass; S23: Calculate the required target deceleration , , , ,in and is the deceleration constant, which indicates the deceleration change per unit pedal position signal. The brake pedal position sensor outputs a signal ranging from 0 to 1, where 0 indicates that the brake pedal is not depressed and 1 indicates that the brake pedal is fully depressed. is the speed influence coefficient, which indicates the influence of speed on the required deceleration. is the load influence factor, which indicates the effect of the load on the required deceleration. is the current speed of the vehicle; S24: Calculate the required braking force ; S25: Setting the braking force threshold determines the initial working mode of the motor and the engine, and the minimum braking force requirement threshold , maximum braking force requirement threshold ,when , only the regenerative braking of the motor is adopted, when The regenerative braking of the motor and the hydraulic braking system work together. , the regenerative braking of the electric motor works together with the hydraulic braking system and activates the hydraulic braking system in advance; S3: Smooth intervention of electric motor braking energy recovery and electronically controlled hydraulic braking. When the driver's braking intention is detected at the initial stage of braking, energy recovery is first performed through the electric motor. The regenerative braking power of the electric motor is dynamically adjusted according to the required braking force. When the electric motor braking cannot meet the braking force requirement, a smooth transition to hydraulic braking is performed. The solenoid valve in the electronically controlled hydraulic braking system is used to dynamically adjust the hydraulic pressure according to the braking force requirement. The rapid pressure building technology is used to build up a pressure of 10MPa within 200ms. Braking decoupling is achieved under specific conditions, that is, only the electric motor is used for braking at a deceleration of 0.2g. The vehicle state and braking force requirement are judged. At low deceleration, only the electric motor is used for braking. At high deceleration, the electronically controlled hydraulic braking system automatically intervenes to smoothly transition the braking response between electric motor braking and hydraulic braking. S31: Initial low deceleration stage, only motor braking is used to dynamically adjust the motor braking power. ,in is the motor braking deceleration, The maximum deceleration of the motor brake; S32: When the electric motor braking cannot meet the braking force requirement, the electronically controlled hydraulic braking system is started, and the solenoid valve is used to dynamically adjust the hydraulic pressure according to the braking force requirement. ,in is the hydraulic brake deceleration; S33: Smooth transition between motor braking and hydraulic braking. When the required deceleration is greater than the maximum deceleration of motor braking, hydraulic braking is gradually started. ,in is the maximum deceleration of hydraulic brake, It is a smooth transition point between electric motor braking and hydraulic braking; S4: Braking response optimization, optimizes the response time of the entire braking system, optimizes the design of the hydraulic pump and accumulator, improves the response speed of the solenoid valve, and adopts fast pressure building technology to achieve fast response and smooth transition between the power system and the braking system in emergency braking, thereby reducing the braking distance; S5: Adjusts braking strategy according to different road conditions. On slippery roads, reduces the use of electric motor braking and increases the proportion of hydraulic braking. On long downhill sections, increases electric motor braking to reduce the risk of thermal attenuation of the friction brake system. Intelligently adjusts the output of the brake system according to road conditions to adapt to changing driving conditions.

2. A new energy light passenger vehicle electronically controlled hydraulic brake optimization method as claimed in claim 1, characterized in that: The S1 detects the converted electrical signal and corrects the signal according to the vehicle speed and load, including: S11: Use a low-pass filter to remove high-frequency noise in the signal, and use an amplifier to amplify the weak signal output by the sensor; S12: Compare the data of the vehicle speed sensor to see whether the logic of the converted electrical signal change is consistent with the vehicle speed change, and observe whether there is any signal offset; S13: reducing the gain of the brake pedal position signal when driving at low speed and with light load, and increasing the gain of the brake pedal position signal when driving at high speed and with heavy load, and establishing a three-dimensional lookup table including vehicle speed, load and corresponding gain coefficient.

3. The method for optimizing the electronically controlled hydraulic brake of a new energy light passenger vehicle according to claim 1, characterized in that: The S5 intelligently adjusts the output of the braking system according to the road condition characteristics to adapt to the changing driving conditions, including: S51: using a wheel speed sensor and a lateral acceleration sensor to identify road condition characteristics and determine whether the road section the vehicle is traveling on is a slippery road or a long downhill section; S52: For slippery roads, the electric motor braking power is reduced to the minimum effective value, the hydraulic brake pressure is dynamically adjusted through the electronic control unit, the ABS system monitors the wheel speed, adjusts the hydraulic pressure, and calculates the slip rate based on the wheel speed and vehicle speed. , ,in is the vehicle speed, For wheel speed, set the slip ratio Threshold value, when the slip ratio exceeds the threshold value, the hydraulic pressure is reduced through the solenoid valve, and when the slip ratio returns to below the threshold value, the hydraulic pressure is increased through the solenoid valve, and the process is repeated; S53: For long downhill sections, the motor braking power is increased to maintain a constant speed while descending. The motor braking power is dynamically adjusted by the electronic control unit according to the changes in slope and speed. , ,in is the vehicle speed, is the slope, monitors the temperature of the brake system, sets the temperature threshold, and adjusts the motor braking power. When the temperature of the brake system does not exceed the threshold, the motor braking power is When the temperature of the braking system exceeds the threshold, the motor braking power is , ,in is the current temperature of the brake system, is the temperature threshold, is the temperature-dependent power reduction factor, The amount of motor braking power that needs to be adjusted.

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