Braking energy recovery system and braking recovery method for pure electric vehicle

Abstract

The invention belongs to the technical field of pure electric vehicles, and particularly relates to a pure electric vehicle braking energy recovery system and a braking recovery method. The system comprises a frame, an accelerator pedal, a brake pedal, a control host, an accelerator signal sensor, a brake signal sensor, a power generation and energy storage system, a brake system, four motors, four tires, a tire pressure sensor and a tire pressure data processing module, and further comprises a friction coefficient fusion module and four road surface friction coefficient sensors. Through independent transmission of four motors and four tires, based on real-time tire pressure, tire adhesive force is calculated, power output and braking power are dynamically distributed, the wheel slipping phenomenon in the braking process is reduced, efficient energy recovery is achieved, and the vehicle braking safety and cruising ability are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of pure electric vehicles, and in particular relates to a brake energy recovery system and a brake recovery method for a pure electric vehicle. Background Art

[0002] With the rapid development of new energy vehicle technology, pure electric vehicles (BEVs), owing to their zero-emission and low-energy consumption advantages, have become a core driver of the automotive industry's transformation. However, range and braking safety remain key issues hindering their widespread adoption. Braking energy regeneration technology, a key means of improving range, can increase vehicle range by 10%-20% by converting wasted kinetic energy during braking into stored electrical energy, making it a hot topic in industry research.

[0003] Existing pure electric vehicle brake energy recovery systems mostly use centralized motor drive or dual-motor axle control mode. The braking force distribution relies on a fixed ratio (such as 6:4 for front and rear axles) or a simple judgment of braking intensity. The centralized motor recovery mode cannot optimize the recovery intensity based on the adhesion differences of each wheel. If a wheel has low adhesion but is forced to recover, energy will be wasted due to slippage, and even the braking effect will be adversely affected. Summary of the Invention

[0004] The purpose of the present invention is to provide a pure electric vehicle braking energy recovery system and braking recovery method, which can...

[0005] The technical solutions adopted by the present invention are as follows:

[0006] A pure electric vehicle braking energy recovery system includes a vehicle frame, on which are mounted an accelerator pedal, a brake pedal, a control host, an accelerator signal sensor, a brake signal sensor, a power generation and energy storage system, a braking system, four motors, and four tires;

[0007] The power generation and energy storage system, braking system, motor, throttle signal sensor, and brake signal sensor are all electrically connected to the control host;

[0008] The system also includes four tire pressure sensors and a tire pressure data processing module. The tire pressure sensors are electrically connected to the tire pressure data processing module. The tire pressure data processing module is built into the control host. The four tire pressure sensors respectively monitor the real-time tire pressure of the four tires and send the real-time tire pressure to the tire pressure data processing module.

[0009] The four motors are independently driven by the four tires;

[0010] The motor includes a power output mode and a power recovery mode;

[0011] When the motor is in power output mode, it converts the electrical energy of the power generation and energy storage system into rotational kinetic energy and outputs it to the wheels;

[0012] When the motor is in the power recovery mode, it recovers the wheel rotational kinetic energy to apply braking force to the wheel, and converts the recovered rotational kinetic energy into electrical energy and stores it in the power generation and energy storage system;

[0013] There are four brake systems, one for each of the four tires, which can drive the brake hydraulic valve to apply adjustable resistance to the wheels according to the command of the control host;

[0014] The control host distributes the kinetic energy output of the four motors according to the throttle signal of the throttle signal sensor and the adhesion calculated based on the four tire pressures;

[0015] The control host distributes the braking power of the four braking systems and four motors according to the brake signal of the brake signal sensor and the adhesion calculated based on the four tire pressures.

[0016] Furthermore, a friction coefficient fusion module and four road friction coefficient sensors are installed on the vehicle frame. The road friction coefficient sensors are electrically connected to the friction coefficient fusion module, and the friction coefficient fusion module is electrically connected to the control host.

[0017] The road friction coefficient sensor is used to collect wheel speed and road image data and send them to the friction coefficient fusion module;

[0018] The friction coefficient fusion module is used to calculate the slip rate based on the wheel speed, determine the road type based on the road image data, and output the real-time friction coefficient between the four wheels and the road surface;

[0019] The control host is used to calculate adhesion according to the throttle signal or brake signal, combined with the four tire pressures and real-time friction coefficients, and distribute the kinetic energy output or braking power of the four motors.

[0020] Furthermore, the road friction coefficient sensor includes a wheel speed sensor and a camera.

[0021] A method for recovering braking energy of a pure electric vehicle comprises the following steps:

[0022] Step 1: Signal acquisition: The throttle signal sensor collects the throttle signal, the brake signal sensor collects the brake signal, and the tire pressure sensor collects the four tire pressures and sends them to the control host through the tire pressure data processing module;

[0023] Step 2: Adhesion calculation: The control host calculates the adhesion of each tire based on the four tire pressures;

[0024] Step 3: Power distribution: If the vehicle is in driving mode, the control unit determines the kinetic energy demand based on the throttle signal and distributes the power output of the four motors according to the adhesion, with more power allocated to wheels with high tire pressure and sufficient adhesion.

[0025] Step 4: Braking recovery: If the vehicle is in braking state, the control host determines the braking power requirement based on the brake signal, and distributes the braking power of the four braking systems and four motors according to the adhesion. The motor braking power is preferentially distributed to the wheels with high adhesion to recover energy, ensuring that the braking power of each wheel does not exceed its adhesion.

[0026] A method for recovering braking energy of a pure electric vehicle comprises the following steps:

[0027] Step 1: Signal acquisition: The throttle signal sensor collects the throttle signal, the brake signal sensor collects the brake signal, and the tire pressure sensor collects the four tire pressures and sends them to the control host through the tire pressure data processing module;

[0028] Step 2: Adhesion calculation: The control host calculates the adhesion of each tire by combining the tire pressures of the four tires and the real-time friction coefficient output by the friction coefficient fusion module;

[0029] Step 3: Power distribution: If the vehicle is in driving mode, the control unit determines the kinetic energy demand based on the throttle signal and distributes the power output of the four motors according to the adhesion, with more power allocated to wheels with high tire pressure and sufficient adhesion.

[0030] Step 4: Braking recovery: If the vehicle is in braking state, the control host determines the braking power requirement based on the brake signal, and distributes the braking power of the four braking systems and four motors according to the adhesion. The motor braking power is preferentially distributed to the wheels with high adhesion to recover energy, ensuring that the braking power of each wheel does not exceed its adhesion.

[0031] Furthermore, in step 4, the control host determines the braking power requirement according to the brake signal:

[0032] If there is a light braking demand, only the motor switches to the power recovery mode, and the braking system does not intervene. Braking and energy recovery are achieved through the motor's reverse resistance torque.

[0033] If the braking demand is moderate, the motor will first switch to the power recovery mode to operate at the maximum recovery torque. If the braking force is insufficient, the braking system will supplement the braking force.

[0034] If it is an emergency braking requirement, only the braking system will implement braking.

[0035] The technical effects achieved by the present invention are:

[0036] A pure electric vehicle braking energy recovery system and braking recovery method of the present invention achieves dynamic distribution of power and braking force by independently controlling four motors and calculating adhesion based on tire pressure (or tire pressure + road friction coefficient), thereby improving braking safety and energy recovery efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1It is a structural diagram of the first embodiment of the present invention;

[0038] Figure 2 It is a structural diagram of the second embodiment of the present invention. DETAILED DESCRIPTION

[0039] In order to make the purpose and advantages of the present invention more clearly understood, the present invention is described in detail below with reference to the following examples. It should be understood that the following text is only used to describe one or more specific embodiments of the present invention and does not strictly limit the scope of protection of the present invention.

[0040] Example 1:

[0041] like Figure 1 As shown, a pure electric vehicle brake energy recovery system includes a vehicle frame, on which are mounted an accelerator pedal, a brake pedal, a control host, an accelerator signal sensor, a brake signal sensor, a power generation and energy storage system, a braking system, a tire pressure sensor, a tire pressure data processing module, a motor, and four tires. The power generation and energy storage system, the braking system, the tire pressure data processing module, the motor, the accelerator signal sensor, and the brake signal sensor are all electrically connected to the control host, and the tire pressure sensor and the tire pressure data processing module are electrically connected;

[0042] It should be noted that in the attached Figure 1 In the diagram, the motor is represented by the symbol M.

[0043] There are four wheels, which are mounted on both sides of the frame respectively.

[0044] There are four tire pressure sensors, which monitor the tire pressures of the four tires respectively and send the real-time tire pressures of the four tires to the tire pressure data processing module.

[0045] The tire pressure data processing module is built into the control host and is used to send the tire pressures of the four tires to the host;

[0046] The motor is fixedly connected to the vehicle frame, and there are four motors. The four motors are independently driven by the four wheels, and the speeds of the four motors can be controlled according to the needs, thereby controlling the speeds of the four wheels.

[0047] The power generation and energy storage system is fixedly connected to the vehicle frame, and the four motors are electrically connected to the power generation and energy storage system. The motors include a power output mode and a power recovery mode.

[0048] When the motor is in power output mode, the motor converts the electrical energy inside the power generation and energy storage system into rotational kinetic energy and outputs it to the wheels to drive the wheels to rotate.

[0049] When the motor is in the power recovery mode, the motor recovers the rotational kinetic energy of the wheels to apply braking power to the wheels, and converts the recovered rotational kinetic energy into electrical energy and stores it in the power generation and energy storage system.

[0050] Among them, the power generation and energy storage system includes a rectifier, a filter, a potentiometer and a battery. The motor is electrically connected to the battery through the rectifier, the filter and the potentiometer in sequence to achieve rectification, filtering and voltage stabilization storage of electric energy.

[0051] In power output mode, the motor operates as an electric motor. The energized coil is forced to rotate in the magnetic field, converting electrical energy into mechanical energy (rotational kinetic energy) to drive the wheels.

[0052] In power recovery mode, the motor operates as a generator, the wheels drive the motor rotor to rotate, and the rotor cuts the magnetic lines of force to generate induced electromotive force (back electromotive force), converting mechanical energy (wheel kinetic energy) into electrical energy to achieve energy recovery.

[0053] The switching between the two modes is completed through the electronic commutation of the motor control circuit, without the need for mechanical structure switching, with fast response speed, and can be converted in real time according to the instructions of the control host.

[0054] There are four braking systems, each corresponding to one of four tires. The braking system is used to apply adjustable resistance to the tires to achieve braking of the tires.

[0055] Specifically, the braking system includes a brake hydraulic valve and an ABS sliding mode controller. When the ABS sliding mode controller receives a brake signal sent by the control host, it drives the brake hydraulic valve to apply resistance to the wheel for braking. The amount of resistance applied to the wheel is determined according to the transmitted brake signal.

[0056] The throttle signal sensor is installed on the throttle pedal and is used to collect the throttle signal and send it to the control host;

[0057] The control host is used to determine the kinetic energy demand of the vehicle when driving based on the throttle signal collected by the throttle signal sensor, calculate the adhesion of the four tires based on the real-time tire pressure, and distribute the kinetic energy output of the four motors based on the adhesion of the four tires;

[0058] Specifically, the control host allocates more power to wheels with high tire pressure and sufficient adhesion, and less power to wheels with low tire pressure. This not only prevents slipping but also ensures that the power is accurately "on the ground", reducing power consumption and improving endurance.

[0059] It should be noted that the power distributed to the tire cannot exceed the adhesion of the tire to reduce wheel slippage.

[0060] The brake signal sensor is installed on the brake pedal and is used to collect the brake signal and send it to the control host;

[0061] The control host is used to determine the braking power requirement of the vehicle when driving based on the brake signal collected by the brake signal sensor, calculate the adhesion of the four tires based on the real-time tire pressure, and distribute the braking power applied to the wheels by the four braking systems and four motors according to the adhesion of the four tires, ensuring that the braking power borne by each wheel is within its adhesion range, thereby effectively preventing wheel slippage, improving the stability and controllability of the vehicle during braking, and reducing the risk of loss of control due to wheel slippage;

[0062] Braking force is distributed according to the adhesion of each wheel. During regenerative braking, braking force is preferentially allocated to wheels with high adhesion, allowing the motor to recover energy more efficiently on these wheels. For example, during light braking, the control unit can increase the braking torque of the motor on wheels with normal tire pressure and high adhesion to recover more energy, while appropriately reducing the braking torque of the motor on wheels with low adhesion to prevent slippage. This achieves precise adaptation of regenerative braking force and braking force distribution, improving energy recovery efficiency.

[0063] The working principle of this technical solution is:

[0064] Power output mode: When the driver steps on the accelerator pedal, the throttle signal sensor sends a signal to the control host. The control host obtains the pressure of the four tires through the tire pressure data processing module, calculates the adhesion of each tire (the higher the tire pressure, the greater the adhesion), and sends instructions to the four motors - the motor corresponding to the wheel with high tire pressure and sufficient adhesion outputs more power, and the motor with low tire pressure outputs less power, ensuring that the power does not exceed the adhesion, avoiding slipping and reducing energy waste.

[0065] Power recovery mode: When the driver steps on the brake pedal, the brake signal sensor sends a signal to the control host, which then determines the braking intensity:

[0066] During light braking, the control unit distributes the braking power of the four motors according to adhesion. The motor corresponding to the wheel with high adhesion (normal tire pressure) enters the recovery mode first, applying the brake by recovering the wheel's rotational kinetic energy (kinetic energy is converted into electrical energy through a rectifier, filter, and potentiometer and stored in the battery). The motor braking power is reduced for the wheel with low adhesion (abnormal tire pressure), and the braking system supplements it to prevent slipping.

[0067] During moderate / emergency braking, the control host coordinates the motor and the braking system. The motor braking power does not exceed the upper limit of adhesion. The remaining braking power is provided by the braking system through the ABS sliding mode controller to control the brake hydraulic valve to ensure smooth braking.

[0068] Example 2:

[0069] like Figure 2 As shown, the difference between this embodiment and the first embodiment is that a friction coefficient fusion module and four road friction coefficient sensors are further installed on the vehicle frame, the four road friction coefficient sensors are electrically connected to the friction coefficient fusion module, and the friction coefficient fusion module is electrically connected to the control host;

[0070] The four road friction coefficient sensors are used to monitor four wheels respectively, and the road friction coefficient sensors include wheel speed sensors and cameras;

[0071] Wherein, the wheel speed sensor is used to collect the wheel speed and send it to the friction coefficient fusion module;

[0072] Wherein, the camera is used to collect image data of the road surface on which the wheels are traveling and send it to the friction coefficient fusion module;

[0073] Among them, the friction coefficient fusion module is used to calculate the slip rate based on the wheel speed, and determine the road surface type based on the driving road surface image data (such as whether the road surface is dry or wet or ice and snow, or whether the road surface is a cement road surface, a dirt road surface, or an asphalt road surface), and then output the real-time friction coefficient between the four wheels and the road surface based on the slip rate and road surface type.

[0074] The control host is used to determine the kinetic energy demand of the vehicle when driving according to the throttle signal collected by the throttle signal sensor, calculate the adhesion of the four tires according to the real-time tire pressure and real-time friction coefficient of the tires, and distribute the kinetic energy output of the four motors according to the adhesion of the four tires;

[0075] The control host is used to determine the braking power requirement of the vehicle when it is driving based on the brake signal collected by the brake signal sensor, calculate the adhesion of the four tires based on the real-time tire pressure and real-time friction coefficient of the tires, and distribute the braking power of the wheels applied by the four braking systems and four motors based on the adhesion of the four tires, ensuring that the braking power borne by each wheel is within its adhesion range, thereby effectively avoiding wheel slippage, improving the stability and controllability of the vehicle during braking, and reducing the risk of loss of control due to wheel slippage.

[0076] The working principle of this technical solution is:

[0077] When driving, if a wheel is on a road with a low friction coefficient (such as water), even if the tire pressure is normal, the control host will reduce its motor power output to avoid slipping;

[0078] When braking, the driver presses the brake pedal, and the brake signal sensor sends a signal to the control host, which determines the braking intensity:

[0079] During light braking, the control host distributes the braking power of the four motors according to adhesion. The motor corresponding to the wheel with high adhesion (normal tire pressure / no water on the road) enters the recovery mode first, applying the brake by recovering the wheel's rotational kinetic energy. The motor braking power is reduced for the wheel with low adhesion (abnormal tire pressure / water on the road), and the braking system supplements it to prevent slipping.

[0080] During moderate / emergency braking, the control host coordinates the motor and the braking system. The motor braking power does not exceed the upper limit of adhesion. The remaining braking power is provided by the braking system through the ABS sliding mode controller to control the brake hydraulic valve to ensure smooth braking.

[0081] Example 3:

[0082] A pure electric vehicle braking recovery method, using a pure electric vehicle braking energy recovery system, is characterized by comprising the following steps:

[0083] Step 1: Signal acquisition: The throttle signal sensor collects the throttle signal, the brake signal sensor collects the brake signal, and the tire pressure sensor collects the four tire pressures and sends them to the control host through the tire pressure data processing module;

[0084] Step 2: Adhesion calculation: The control host calculates the adhesion of each tire based on the four tire pressures;

[0085] Step 3: Power distribution: If the vehicle is in driving mode, the control unit determines the kinetic energy demand based on the throttle signal and distributes the power output of the four motors according to the adhesion, with more power allocated to wheels with high tire pressure and sufficient adhesion.

[0086] Step 4: Braking recovery: If the vehicle is in braking state, the control host determines the braking power requirement based on the brake signal, and distributes the braking power of the four braking systems and four motors according to the adhesion. The motor braking power is preferentially distributed to the wheels with high adhesion to recover energy, ensuring that the braking power of each wheel does not exceed its adhesion.

[0087] It should be noted that if the system includes a friction coefficient fusion module and a road friction coefficient sensor, in step 2, the control host calculates the adhesion of each tire based on the four tire pressures and the real-time friction coefficient output by the friction coefficient fusion module.

[0088] In step 4, the control host determines the braking power requirement based on the brake signal:

[0089] If there is a light braking requirement, only the motor switches to power recovery mode, the braking system does not intervene, and braking and energy recovery are achieved through the motor's reverse resistance torque.

[0090] If the braking demand is moderate, the motor will first switch to power recovery mode to operate with maximum recovery torque. If the braking force is insufficient, the braking system will supplement the braking force.

[0091] If emergency braking is required, only the braking system will implement braking through the ABS sliding mode controller to ensure safety.

[0092] In summary, this technical solution achieves dynamic distribution of power and braking force through independent control of four motors and calculation of adhesion based on tire pressure (or tire pressure + road friction coefficient), thereby improving braking safety and energy recovery efficiency.

[0093] The foregoing is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications are also within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described or explained herein shall, unless otherwise specified or limited, be implemented in accordance with conventional means in the art.

Claims

1. A pure electric vehicle braking energy recovery system, characterized by: The vehicle comprises a frame on which an accelerator pedal, a brake pedal, a control host, an accelerator signal sensor, a brake signal sensor, a power generation and energy storage system, a braking system, four motors and four tires are installed; The power generation and energy storage system, braking system, motor, throttle signal sensor, and brake signal sensor are all electrically connected to the control host; The system also includes four tire pressure sensors and a tire pressure data processing module. The tire pressure sensors are electrically connected to the tire pressure data processing module. The tire pressure data processing module is built into the control host. The four tire pressure sensors respectively monitor the real-time tire pressure of the four tires and send the real-time tire pressure to the tire pressure data processing module. The four motors are independently driven by the four tires; The motor includes a power output mode and a power recovery mode; When the motor is in power output mode, it converts the electrical energy of the power generation and energy storage system into rotational kinetic energy and outputs it to the wheels; When the motor is in the power recovery mode, it recovers the wheel rotational kinetic energy to apply braking force to the wheel, and converts the recovered rotational kinetic energy into electrical energy and stores it in the power generation and energy storage system; There are four brake systems, one for each of the four tires, which can drive the brake hydraulic valve to apply adjustable resistance to the wheels according to the command of the control host; The control host distributes the kinetic energy output of the four motors according to the throttle signal of the throttle signal sensor and the adhesion calculated based on the four tire pressures; The control host distributes the braking power of the four braking systems and four motors according to the brake signal of the brake signal sensor and the adhesion calculated based on the four tire pressures.

2. The pure electric vehicle braking energy recovery system according to claim 1, characterized in that: The frame is also equipped with a friction coefficient fusion module and four road friction coefficient sensors, the road friction coefficient sensors are electrically connected to the friction coefficient fusion module, and the friction coefficient fusion module is electrically connected to the control host; The road friction coefficient sensor is used to collect wheel speed and road image data and send them to the friction coefficient fusion module; The friction coefficient fusion module is used to calculate the slip rate based on the wheel speed, determine the road type based on the road image data, and output the real-time friction coefficient between the four wheels and the road surface; The control host is used to calculate adhesion according to the throttle signal or brake signal, combined with the four tire pressures and real-time friction coefficients, and distribute the kinetic energy output or braking power of the four motors.

3. The pure electric vehicle braking energy recovery system according to claim 2, characterized in that: The road friction coefficient sensor includes a wheel speed sensor and a camera.

4. A pure electric vehicle braking energy recovery system according to any one of claims 1 to 3, characterized in that: The braking system includes a brake hydraulic valve and an ABS sliding mode controller, and the ABS sliding mode controller is electrically connected to a control host.

5. A pure electric vehicle braking energy recovery system according to any one of claims 1 to 3, characterized in that: The power generation and energy storage system includes a rectifier, a filter, a potentiometer and a battery, and the motor is electrically connected to the battery via the rectifier, the filter and the potentiometer in sequence.

6. A method for recovering braking energy of a pure electric vehicle, using the pure electric vehicle braking energy recovery system according to claim 1, characterized in that: The following steps are involved: Step 1: Signal acquisition: The throttle signal sensor collects the throttle signal, the brake signal sensor collects the brake signal, and the tire pressure sensor collects the four tire pressures and sends them to the control host through the tire pressure data processing module; Step 2: Adhesion calculation: The control host calculates the adhesion of each tire based on the four tire pressures; Step 3: Power distribution: If the vehicle is in driving mode, the control unit determines the kinetic energy demand based on the throttle signal and distributes the power output of the four motors according to the adhesion, with more power allocated to wheels with high tire pressure and sufficient adhesion. Step 4: Braking recovery: If the vehicle is in braking state, the control host determines the braking power requirement based on the brake signal, and distributes the braking power of the four braking systems and four motors according to the adhesion. The motor braking power is preferentially distributed to the wheels with high adhesion to recover energy, ensuring that the braking power of each wheel does not exceed its adhesion.

7. A method for recovering braking energy of a pure electric vehicle, using the pure electric vehicle braking energy recovery system according to claim 2, characterized in that: The following steps are involved: Step 1: Signal acquisition: The throttle signal sensor collects the throttle signal, the brake signal sensor collects the brake signal, and the tire pressure sensor collects the four tire pressures and sends them to the control host through the tire pressure data processing module; Step 2: Adhesion calculation: The control host calculates the adhesion of each tire by combining the tire pressures of the four tires and the real-time friction coefficient output by the friction coefficient fusion module; Step 3: Power distribution: If the vehicle is in driving mode, the control unit determines the kinetic energy demand based on the throttle signal and distributes the power output of the four motors according to the adhesion, with more power allocated to wheels with high tire pressure and sufficient adhesion. Step 4: Braking recovery: If the vehicle is in braking state, the control host determines the braking power requirement based on the brake signal, and distributes the braking power of the four braking systems and four motors according to the adhesion. The motor braking power is preferentially distributed to the wheels with high adhesion to recover energy, ensuring that the braking power of each wheel does not exceed its adhesion.

8. A method for recovering braking energy of a pure electric vehicle according to any one of claims 6-7, characterized in that: In step 4, the control host determines the braking power requirement based on the brake signal: If there is a light braking demand, only the motor switches to the power recovery mode, and the braking system does not intervene. Braking and energy recovery are achieved through the motor's reverse resistance torque. If the braking demand is moderate, the motor will first switch to the power recovery mode to operate at the maximum recovery torque. If the braking force is insufficient, the braking system will supplement the braking force. If it is an emergency braking requirement, only the braking system will implement braking.

Images