Automatic cruise torque control method and device

Abstract

The invention relates to an automatic cruise torque control method and device, and relates to the field of pure electric heavy commercial vehicles using lithium iron phosphate batteries, and the automatic cruise torque control method comprises the following steps: judging whether the current gradient is greater than-1% or not; judging the real-time speed of the vehicle in the current state; if the current vehicle speed is smaller than the set target cruising vehicle speed, the next step is executed, and otherwise, the next step is skipped; the vehicle is accelerated by means of gravitational potential energy; firstly, the allowable maximum recovery torque is calculated, then the energy recovery torque requested by the vehicle control unit and the maximum energy recovery torque allowed by the power battery management system are compared, the larger value is selected and sent to the motor controller, and meanwhile no matter how large a deceleration request is sent to the electronic braking system by the vehicle control unit, the deceleration request is not responded. Gravitational potential energy can be fully utilized through the conditions of the vehicle and energy recovery limitation of the power battery, the energy utilization rate in the low-temperature environment is increased, and mechanical braking loss is reduced.

Description

Technical Field

[0001] The invention relates to an electric-driven commercial automatic cruise energy-saving control system, in particular to a pure electric heavy-duty commercial vehicle using a lithium iron phosphate battery. Background Art

[0002] Currently, most heavy-duty commercial vehicles on the market are equipped with a cruise control system, which allows the vehicle to run at the speed set by the driver, reducing driver fatigue and avoiding unnecessary speed changes.

[0003] However, for electric commercial vehicles, due to the low-temperature activity of lithium ions, the energy recovery of power batteries in low-temperature environments is greatly reduced. When the vehicle is in a low-temperature environment and driving downhill, in order to maintain the target cruising speed, only part of the gravitational potential energy is converted into electrical energy through the motor, and the rest is converted into heat energy through the braking system. Summary of the invention

[0004] The present invention aims to provide an automatic cruise torque control method and device, which fully utilizes gravitational potential energy through vehicle conditions and power battery energy recovery restrictions, improves energy utilization in low temperature environments, and reduces mechanical braking losses.

[0005] In order to achieve the above object, the technical solution of the present invention provides an automatic cruise torque control method, which comprises the following steps:

[0006] Step 1: Determine the slope i of the current vehicle position n Is it greater than -1%? If so, the motor and brake system torque request issued by the vehicle control unit VCU is not identified and processed. Otherwise, the next step is entered;

[0007] Step 2: Determine the vehicle's real-time speed v in the current state n Whether it is between 70km / h and 90km / h. If not, the motor and brake system torque request issued by the vehicle control unit VCU is not identified and processed. Otherwise, the next step is entered;

[0008] Step 3: If the current vehicle speed v n Less than the set target cruising speed v t When , execute step 4, otherwise execute step 5;

[0009] Step 4: filter the torque request sent by the vehicle control unit VCU to the motor controller MCU, and actually send a T mn = 0 signal, that is, the vehicle is accelerated by gravity potential energy;

[0010] Step 5: First, calculate the maximum allowable regenerative torque T according to the current state of the battery, input current limit, voltage and motor speed. bl =I l ×U n / n n ×9550, then compare the energy recovery torque T requested by the vehicle control unit VCU mr and the maximum energy recovery torque T allowed by the power battery management system BMS bl , select a larger value to send to the motor controller MCU, and no matter how much deceleration request a the vehicle control unit VCU sends to the electronic brake system EBS br , do not respond, that is, T mn =Max(T mr , T bl ), a bn =0.

[0011] Preferably, when the vehicle adaptive cruise control function ACC is activated and the advanced driving assistance system ADAS calculates and feedbacks that the time tn between the current state and the collision with the preceding vehicle is greater than a set threshold tc, the torque control method is activated.

[0012] The technical solution of the present invention also provides an automatic cruise torque control device, which can execute the above-mentioned automatic cruise torque control method.

[0013] Preferably, the torque control device is electrically connected to the VCU, MCU, EBS, BMS, and ADAS.

[0014] In summary, the present invention includes the following beneficial technical effects:

[0015] The present invention can make full use of gravitational potential energy through the vehicle's condition and the power battery energy recovery limit, improve the energy utilization rate in a low temperature environment, and reduce mechanical braking loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a connection diagram of the automatic cruise torque control device in the present invention;

[0017] Figure 2 It is a control logic diagram of the automatic cruise torque control method in the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] The present invention comprises an automatic cruise torque control device and a set of drive motor and brake torque control methods;

[0020] The control device has the functions of data storage, calculation, real-time positioning and communication with VCU, MCU, EBS, BMS and ADAS, among which:

[0021] VCU: Vehicle Control Unit is one of the core components in modern automotive electronic control systems. It is responsible for receiving and processing signals from various sensors and executing various control instructions to ensure the stable operation of the vehicle.

[0022] MCU: Motor Control Unit is an electronic device used to control the operation of a motor. It receives input signals and precisely controls the motor to adjust parameters such as motor speed, torque, and direction.

[0023] EBS: Electronic Brake System is an advanced active safety device for automobiles. It monitors and analyzes the vehicle's speed, weight, road conditions, etc. in real time through sensors, controllers and other electronic devices, and then sends control instructions to the brake system to achieve a more accurate and safer braking effect.

[0024] BMS: The Battery Management System (BMS) is a system for monitoring and managing batteries. It collects and calculates parameters such as voltage, current, temperature, and SOC, and then controls the battery's charge and discharge process to protect the battery and improve the battery's overall performance. It is an important link between on-board power batteries and electric vehicles.

[0025] ADAS: Advanced Driving Assistance System uses a variety of sensors installed on the car (millimeter wave radar, lidar, monocular / binocular cameras and satellite navigation) to sense the surrounding environment at any time during driving, collect data, identify, detect and track static and dynamic objects, and combine navigation map data to perform systematic calculations and analysis, so as to make the driver aware of possible dangers in advance, effectively increasing the comfort and safety of car driving.

[0026] The control device communicates with VCU, MCU, EBS and BMS through CAN line, such as Figure 1As shown in Figure 2, when the vehicle's adaptive cruise control (ACC) function is activated and ADAS calculates and feedbacks the current state and the collision time t of the front vehicle n Greater than the set threshold t c , the torque control method is also activated.

[0027] The specific control logic of the torque control method is as follows: Figure 2 As shown:

[0028] in:

[0029] v n : Indicates the current speed of the vehicle;

[0030] v t : Indicates the target cruising speed set by ACC;

[0031] i n : Indicates the road slope at the current location;

[0032] I l : Indicates the maximum charging current limit set by the BMS according to the current battery status;

[0033] U n : Indicates the current voltage of the power battery;

[0034] n n : Indicates the current speed of the drive motor;

[0035] T mr : Indicates the torque request sent by VCU to MCU;

[0036] T mn : Indicates the torque request actually sent by the control device to the MCU;

[0037] T bl : Indicates the maximum regenerative torque calculated based on the BMS and the current state of the motor;

[0038] a br : Indicates the braking deceleration request sent by VCU to EBS;

[0039] a bn : Indicates the braking deceleration request actually sent by the control device to the EBS.

[0040] The specific working steps are as follows:

[0041] 1) Determine the slope i of the vehicle’s current position n Is it greater than -1%? If so, the motor and brake system torque request from the VCU will not be identified and processed. Otherwise, the next step is entered;

[0042] 2) Determine the real-time speed v of the vehicle in the current staten Is it between 70km / h and 90km / h? If not, the motor and brake system torque request from the VCU will not be identified and processed. Otherwise, the next step is entered;

[0043] 3) If the current vehicle speed v n Less than the set target cruising speed v t When , execute step 4, otherwise execute step 5;

[0044] 4) The system only filters the torque request sent by VCU to MCU and actually sends T mn = 0 signal, that is, the vehicle is accelerated by gravity potential energy;

[0045] 5) At this time, the system will first calculate the maximum allowable regenerative torque T according to the current state of the battery: input current limit, voltage and motor speed. bl =I l ×U n / n n ×9550, then the system will compare the energy recovery torque T requested by the VCU mr and the maximum energy recovery torque T allowed by the BMS bl , select a larger value and send it to MCU. At the same time, no matter how large the deceleration request a is sent by VCU to EBS br , do not respond, that is, T mn =Max(T mr , T bl ), a bn =0.

[0046] Finally, it should be noted that the above 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 aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An automatic cruise torque control method, characterized in that: The following steps are involved: Step 1: Determine the slope i of the current vehicle position n Is it greater than -1%? If so, the motor and brake system torque request issued by the vehicle control unit VCU is not identified and processed. Otherwise, the next step is entered; Step 2: Determine the vehicle's real-time speed v in the current state n Whether it is between 70km / h and 90km / h. If not, the motor and brake system torque request issued by the vehicle control unit VCU is not identified and processed. Otherwise, the next step is entered; Step 3: If the current vehicle speed v n Less than the set target cruising speed v t When , execute step 4, otherwise execute step 5; Step 4: filter the torque request sent by the vehicle control unit VCU to the motor controller MCU, and actually send a T mn = 0 signal, that is, the vehicle is accelerated by gravity potential energy; Step 5: First, calculate the maximum allowable regenerative torque T according to the current state of the battery, input current limit, voltage and motor speed. bl =I l ×U n / n n ×9550, then compare the energy recovery torque T requested by the vehicle control unit VCU mr and the maximum energy recovery torque T allowed by the power battery management system BMS bl , select a larger value to send to the motor controller MCU, and no matter how much deceleration request a the vehicle control unit VCU sends to the electronic brake system EBS br , do not respond, that is, T mn =Max(T mr , T bl ), a bn =0.

2. The automatic cruise torque control method according to claim 1, characterized in that: When the vehicle's adaptive cruise control function ACC is activated and the advanced driving assistance system ADAS calculates and feedbacks that the current state and the collision time tn with the preceding vehicle are greater than the set threshold tc, the torque control method is activated.

3. An automatic cruise torque control device, characterized in that: The automatic cruise torque control method as claimed in claim 1 or 2 can be executed.

4. The automatic cruise torque control device according to claim 3, characterized in that: The torque control device is electrically connected to the VCU, MCU, EBS, BMS, and ADAS.

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