New energy heavy truck braking energy recovery method and system and new energy heavy truck

Abstract

The invention discloses a new energy heavy truck braking energy recovery method and system and a new energy heavy truck. The method comprises the steps that the vehicle load and the vehicle speed are obtained; whether pneumatic braking is applied or not is determined according to whether the deceleration demand value is larger than a set threshold value or not; if the required value is lower than the threshold value and the vehicle speed is enough, first braking force is applied by the motor preferentially, then the difference value between the required deceleration and the actual deceleration is compared in real time, and if the difference value exceeds the threshold value and lasts for a certain time, pneumatic braking is started to supplement torque. The system comprises a brake pedal, an electronic brake system, a motor controller and a vehicle control unit, and electromechanical braking smooth coupling is achieved through cooperative control of an EBS and a VCU. The energy recovery efficiency is remarkably improved, the driving comfort is improved, the mechanical braking abrasion is reduced, the braking stability is preferentially guaranteed when the ABS / ESC is activated, and energy conservation, safety and economical efficiency are achieved.

Description

Technical Field

[0001] This invention belongs to the field of new energy technology, specifically relating to a method, system, and new energy heavy truck for brake energy recovery. Background Technology

[0002] With the increasing maturity of environmental protection policies, energy impact, and new energy control technologies, the proportion of new energy heavy trucks in the commercial vehicle sector has been rising continuously in recent years. Data shows that the proportion of new energy heavy trucks has reached 24%.

[0003] However, due to limitations in battery technology, new energy trucks are significantly heavier, weighing 1-1.5 tons more than traditional gasoline-powered vehicles. Furthermore, their range is limited by battery capacity, preventing them from meeting long-range requirements. Currently, new energy trucks primarily target the short-haul market and regional transportation. To ensure customer availability, energy recovery has become an indispensable system for new energy trucks, with regenerative braking accounting for approximately 25% of the total.

[0004] However, new energy heavy trucks do not only brake through energy recovery. Their traditional braking methods, such as air braking, are also important. However, when energy recovery braking and air braking are used in combination, braking jerking and poor comfort are prone to occur. Summary of the Invention

[0005] The purpose of this invention is to propose a method, system, and new energy heavy-duty truck for brake energy recovery, in order to solve the problems in the prior art.

[0006] Therefore, the present invention provides a method for recovering braking energy in new energy heavy-duty trucks, comprising:

[0007] Obtain vehicle load and speed;

[0008] Obtain the deceleration requirement value and determine whether the deceleration requirement value is greater than the deceleration threshold. If it is greater, apply a second braking force.

[0009] Based on the deceleration requirement value being less than the deceleration threshold and the vehicle speed being greater than the vehicle speed threshold, and based on the deceleration requirement value and the vehicle load, the motor applies a corresponding first braking force to obtain the actual deceleration value.

[0010] The difference between the required deceleration value and the actual deceleration value is obtained, and it is determined whether the difference is greater than a preset difference threshold within a preset time. If it is greater, a second braking force is applied simultaneously.

[0011] In one embodiment, when determining whether the difference within a preset time is greater than a preset difference threshold, it is simultaneously determined whether the active safety system is activated. If activated, the first braking force is stopped and the second braking force is continued to be applied.

[0012] In one embodiment, the deceleration requirement value includes a first deceleration requirement value. When the first deceleration requirement value is ≤0.2g, the braking force is the first braking force. When the deceleration requirement value and the actual deceleration value are greater than the preset difference threshold within a preset time, the braking force is the first braking force and the second braking force.

[0013] In one embodiment, the deceleration requirement value includes a second deceleration requirement value. When the second deceleration requirement value is 0.2g-0.4g, the braking force is the first braking force. When the deceleration requirement value and the actual deceleration value are greater than the preset difference threshold within a preset time, the braking force is the first braking force and the second braking force.

[0014] In one embodiment, the deceleration requirement value includes a third deceleration requirement value, and when the third deceleration requirement value is greater than 0.5g, the braking force is a second braking force.

[0015] In one embodiment, the first braking force is the negative torque applied by the motor, and the second braking force is at least a pneumatic brake.

[0016] In one embodiment, the deceleration is calibrated to correspond to the brake pedal opening.

[0017] On the other hand, a new energy heavy-duty truck braking energy recovery system is also provided, including:

[0018] A brake pedal, used to input a braking request;

[0019] An electronic braking system, the electronic braking system including an electronic control unit, the electronic control unit acquiring the braking request and pedal travel of the brake pedal and applying a second braking force to the vehicle;

[0020] A motor controller for controlling the negative torque of a motor to apply a first braking force to the vehicle;

[0021] The vehicle controller receives braking requests from the electronic braking system based on pedal travel and controls the motor controller to apply negative torque to the motor.

[0022] In one embodiment, the brake pedal includes a displacement sensor and a brake signal transmitter. The displacement sensor is used to detect the brake pedal slip rate and send a displacement voltage signal to the vehicle controller. The vehicle controller controls the motor controller to apply negative torque to the motor.

[0023] On the other hand, a new energy heavy truck is also provided, including a new energy heavy truck braking energy recovery system.

[0024] Beneficial effects:

[0025] This invention significantly improves the braking energy recovery efficiency of new energy heavy trucks through the coordinated control and redundant design of the EBS system, effectively solving the problem of jerking sensation during electromechanical braking coupling and greatly improving driving comfort. Simultaneously, the system maximizes the use of electric motor braking, significantly reducing wear on mechanical brakes, effectively extending their service life and reducing maintenance costs, and prioritizing braking stability when safety systems such as ABS / ESC are activated. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 A schematic flowchart of the new energy heavy truck braking energy recovery method provided by the present invention.

[0028] Figure 2 The calibration curves corresponding to deceleration and pedal opening in the new energy heavy truck braking energy recovery method provided by the present invention are shown.

[0029] Figure 3 This is a schematic diagram of the new energy heavy truck braking energy recovery system provided by the present invention.

[0030] Figure 4 This is a schematic diagram illustrating the interaction between the EBS (Energy Recovery System) and the vehicle in the new energy heavy-duty truck braking energy recovery system provided by this invention.

[0031] Figure 5 This is a schematic diagram of the brake pedal in the new energy heavy truck braking energy recovery system provided by the present invention.

[0032] In the diagram: 1. Brake pedal; 2. Electronic braking system; 3. Motor controller; 4. Vehicle controller; 5. Displacement sensor; 6. Brake signal transmitter. Detailed Implementation

[0033] The invention will be more readily understood by referring to the following detailed description of preferred embodiments and included examples. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of conflict, the definitions in this specification shall prevail.

[0034] like Figure 1As shown, a method for recovering braking energy in a new energy heavy-duty truck includes:

[0035] The vehicle load and speed are important information. New energy heavy trucks have a large self-weight and need to carry goods, so it is necessary to obtain the vehicle load to facilitate the subsequent application of braking force by the motor so that the vehicle can achieve the required deceleration value.

[0036] The deceleration requirement value is obtained, and it is determined whether the deceleration requirement value is greater than the deceleration threshold. If it is greater, a second braking force is applied. The deceleration requirement value can be determined by the opening degree of brake pedal 1 after the driver depresses it. This application determines the deceleration requirement value through the VCU (vehicle controller 4) after the driver depresses brake pedal 1 by calibrating the corresponding curve of braking deceleration and brake pedal 1 opening. When the deceleration requirement value is too large, the braking requirement cannot be met by energy recovery braking through the negative torque of the motor alone. In this case, there is no need to perform motor braking, and air braking is directly applied to ensure that the braking requirement is met and the vehicle driving safety is guaranteed.

[0037] When the deceleration demand is less than the deceleration threshold and the vehicle speed is greater than the vehicle speed threshold (i.e., when the deceleration demand is relatively small), the motor applies a corresponding first braking force based on the deceleration demand and vehicle load. The first braking force is the braking brought by the negative torque of the motor, which can ensure comfort during braking and reduce the feeling of braking jerking. The actual deceleration value is obtained after applying the first braking force. The vehicle speed threshold can be 4 km / h. When the vehicle speed is too low, the brake pedal 1 can be released directly, and energy recovery exits to the intervention value for driving.

[0038] The difference between the required deceleration value and the actual deceleration value is obtained, and it is determined whether the difference is greater than a preset difference threshold within a preset time. If it is greater, that is, when the braking demand cannot be fully met by the first braking force alone, the second braking force is applied at the same time. Under the combined action of the first braking force and the second braking force, braking is performed simultaneously. There is no need to apply the second braking force, such as mechanical braking, in the initial stage of braking, which can reduce the wear of mechanical brakes and improve the service life of the braking system.

[0039] In another embodiment, when determining whether the time difference is greater than a preset threshold, it is simultaneously determined whether the active safety system is activated. If activated, the first braking force is stopped, and the second braking force is applied. The first braking force is electric motor braking, and the second braking force is air braking. Specifically, when the ABS (Anti-lock Braking System), BA (Brake Assist System), and ESC (Electronic Stability Control System) are activated, regenerative braking is deactivated, and air braking is fully engaged. This effectively avoids any interference or conflict between the regenerative braking system and the precise and rapid active safety control, thus preventing any impact on driving safety.

[0040] In one embodiment, the deceleration requirement value includes a first deceleration requirement value. When the first deceleration requirement value is ≤0.2g, the braking force is the first braking force. When the deceleration requirement value and the actual deceleration value are greater than the preset difference threshold within a preset time, the braking force is the first braking force and the second braking force.

[0041] Specifically, when the driver requires a deceleration of ≤0.2g, the deceleration can be calibrated according to the motor's capability, such as... Figure 2 To suit the driver's driving habits, braking is entirely provided by the electric motor. In this state, if the driver activates the regenerative braking system (EBS), the EBS (Electronic Braking System 2) adds a 30% negative torque based on the real-time negative torque feedback from the VCU. For example, if the current negative torque is 15%, and 30% is needed to achieve 0.2g, then an additional 30% negative torque is added to ensure comfort during braking and reduce braking jerking. Conversely, if there is no motor negative torque, i.e., no braking force, the EBS requests a percentage of torque from the VCU for braking. When the required deceleration is greater than or equal to the actual deceleration exceeding 0.2m / s², the EBS will apply the additional torque. 2 If the delay exceeds 300ms, the EBS (Energy Recovery System) will switch to a supplemental air strategy, and air braking will begin to engage to meet deceleration requirements and ensure driving safety. In other words, if the energy recovery system can meet the braking demand, then braking will be entirely provided by the energy recovery system; if it cannot, then traditional mechanical braking will intervene to meet the braking demand, thereby increasing the proportion of energy recovery.

[0042] In one embodiment, the deceleration requirement value includes a second deceleration requirement value. When the second deceleration requirement value is 0.2g-0.4g, the braking force is the first braking force. When the deceleration requirement value and the actual deceleration value are greater than the preset difference threshold within a preset time, the braking force is the first braking force and the second braking force.

[0043] Specifically, when the driver requires a deceleration of 0.2g-0.4g, the EBS (Electronic Braking System) enters hybrid braking. If the driver activates regenerative braking at this time, the EBS superimposes the motor's negative torque based on the VCU (Vehicle Control Unit) feedback, ensuring comfort during braking and reducing braking jerkiness. If there is no motor negative torque at this time, the EBS requests a percentage of the VCU torque for braking. When the required deceleration is greater than or equal to the actual deceleration, the braking speed will exceed 0.2m / s². 2 If the delay exceeds 300ms, EBS will enter the air replenishment strategy, and air braking will begin to intervene.

[0044] In one embodiment, the deceleration requirement value includes a third deceleration requirement value, and when the third deceleration requirement value is greater than 0.5g, the braking force is a second braking force.

[0045] Specifically, when the driver needs a deceleration greater than 0.5g and the pedal is pressed quickly, the EBS will engage emergency braking and directly apply air braking to ensure braking safety.

[0046] It should be noted that the first, second, and third deceleration requirements can be calibrated according to actual needs.

[0047] In one embodiment, when the vehicle is on a long downhill slope and undergoes brief braking (the vehicle has not stopped yet, i.e., the driver presses and releases the brake pedal 1), if auxiliary brake energy recovery is activated at this time, EBS requests the negative torque to exit to the intervention value to ensure braking comfort. That is, the initial braking force of the motor is not instantly reduced to zero, but is smoothly weakened to a lower preset level, i.e., the intervention value, to avoid the vehicle accelerating due to a sudden loss of braking force, which would cause a jerking sensation.

[0048] like Figure 3-4 As shown, on the other hand, a new energy heavy-duty truck braking energy recovery system is also provided, including:

[0049] Brake pedal 1, which is used to input a braking request;

[0050] Electronic braking system 2, the electronic braking system 2 includes an electronic control unit, the electronic control unit acquires the braking request and pedal travel of brake pedal 1 and applies a second braking force to the vehicle;

[0051] Motor controller 3, the motor controller 3 being used to control the negative torque of the motor to apply a first braking force to the vehicle;

[0052] The vehicle controller 4 is used to receive braking requests sent by the electronic braking system 2 based on the pedal travel, and the vehicle controller 4 controls the motor controller 3 to apply negative torque to the motor.

[0053] like Figure 3 As shown, the displacement sensor 5 on the brake pedal 1 converts the driver's braking intention into a displacement voltage signal. This signal is first sent to the brake EBS for decision-making. The EBS calculates the required braking force based on this signal and sends a negative torque control request to the vehicle VCU. The VCU, as the coordination center, converts this request into specific execution instructions and sends them to the motor controller 3 MCU. Finally, the MCU controls the motor to generate precise negative torque, achieving braking and energy recovery.

[0054] In one embodiment, such as Figure 5As shown, the brake pedal 1 includes a displacement sensor 5 and a brake signal transmitter 6, and sends a displacement voltage signal to the vehicle controller 4. The vehicle controller 4 controls the motor controller 3 to apply negative torque to the motor. The brake pedal 1 retains the original displacement sensor 5. When the braking system malfunctions, the EBS energy recovery fails. The VCU requests energy recovery based on the displacement sensor 5 signal and monitors the slip ratio in real time to ensure a higher proportion of braking energy recovery. Specifically, the displacement sensor 5 signal is directly connected to the VCU. When the main braking EBS-ECU system malfunctions, the VCU can bypass the failed EBS and directly obtain the driver's original braking intention (displacement voltage signal). The VCU's internal algorithm directly calculates the required braking force and requests negative torque from the MCU to achieve energy recovery braking. Simultaneously, the VCU monitors the wheel slip ratio in real time and actively limits the motor's negative torque to prevent wheel lock-up. Therefore, while ensuring braking safety, it can still maintain a considerable level of energy recovery function, greatly improving the system's safety and reliability.

[0055] On the other hand, the present invention also provides a new energy heavy truck, which includes a new energy heavy truck braking energy recovery system.

[0056] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for recovering braking energy in a new energy heavy-duty truck, characterized in that, include: Obtain vehicle load and speed; Obtain the deceleration requirement value and determine whether the deceleration requirement value is greater than the deceleration threshold. If it is greater, apply a second braking force. Based on the deceleration requirement value being less than the deceleration threshold and the vehicle speed being greater than the vehicle speed threshold, and based on the deceleration requirement value and the vehicle load, the motor applies a corresponding first braking force to obtain the actual deceleration value. The difference between the required deceleration value and the actual deceleration value is obtained, and it is determined whether the difference is greater than a preset difference threshold within a preset time. If it is greater, a second braking force is applied simultaneously.

2. The recycling method according to claim 1, characterized in that, When determining whether the difference within a preset time period is greater than a preset difference threshold, it is also determined whether the active safety system is activated. If activated, the first braking force is stopped and the second braking force is applied.

3. The recycling method according to claim 1, characterized in that, The deceleration requirement value includes a first deceleration requirement value. When the first deceleration requirement value is ≤0.2g, the braking force is the first braking force. When the deceleration requirement value and the actual deceleration value are greater than the preset difference threshold within a preset time, the braking force is the first braking force and the second braking force.

4. The recycling method according to claim 1, characterized in that, The deceleration requirement value includes a second deceleration requirement value. When the second deceleration requirement value is 0.2g-0.4g, the braking force is the first braking force. When the deceleration requirement value and the actual deceleration value are greater than the preset difference threshold within a preset time, the braking force is the first braking force and the second braking force.

5. The recycling method according to claim 1, characterized in that, The deceleration requirement value includes a third deceleration requirement value. When the third deceleration requirement value is greater than 0.5g, the braking force is the second braking force.

6. The recycling method according to claim 1, characterized in that, The first braking force is the negative torque applied by the motor, and the second braking force is at least air braking.

7. The recycling method according to claim 1, characterized in that, The deceleration and brake pedal opening are calibrated so that the required deceleration value corresponds to the brake pedal opening.

8. A braking energy recovery system for new energy heavy-duty trucks, characterized in that, include: A brake pedal, used to input a braking request; An electronic braking system, the electronic braking system including an electronic control unit, the electronic control unit acquiring the braking request and pedal travel of the brake pedal and applying a second braking force to the vehicle; A motor controller for controlling the negative torque of a motor to apply a first braking force to the vehicle; The vehicle controller receives braking requests from the electronic braking system based on pedal travel and controls the motor controller to apply negative torque to the motor.

9. The recycling system according to claim 8, characterized in that, The brake pedal includes a displacement sensor and a brake signal transmitter, and sends a displacement voltage signal to the vehicle controller. The vehicle controller then controls the motor controller to apply negative torque to the motor.

10. A new energy heavy-duty truck, characterized in that, Includes the new energy heavy truck braking energy recovery system as described in claim 8.

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