CN-122009177-A - Vehicle composite braking control method and system and vehicle

Abstract

The application provides a vehicle composite braking control method and system and a vehicle. Vehicles include a variety of braking sources. The method comprises the steps of acquiring road information in front of a vehicle, determining whether the vehicle is in a normal running area or a long downhill area based on the road information in front of the vehicle, and executing torque distribution of various braking sources according to a short-distance braking algorithm when the vehicle is braked in the normal running area, wherein the torque distribution of the hydraulic retarder is limited when the vehicle is braked in the normal running area and a driver pulls down a retarder handle, and executing torque distribution of various braking sources according to a long-distance braking algorithm when the vehicle is braked in the long downhill area. The application solves the problem of the cooperative braking of multiple braking sources, realizes the reasonable distribution of multiple braking sources, and can improve the energy utilization rate of the whole vehicle while ensuring the braking effect.

Inventors

• HAN LELE
• SHI JUNPING
• SUN YAN
• HAN LINPEI
• TANG XIAOYONG

Assignees

• 浙江吉利控股集团有限公司
• 浙江远程新能源商用车集团有限公司
• 浙江远程商用车研发有限公司

Dates

Publication Date

20260512

Application Date

20260225

Claims (15)

1. 1. The vehicle composite brake control method is characterized in that the vehicle comprises a plurality of brake sources, the plurality of brake sources comprise mechanical brake, hydraulic retarder brake, motor brake controlled by a brake pedal and electric retarder brake, the electric retarder and the hydraulic retarder are controlled by retarder handles, and the motor brake controlled by the brake pedal and the electric retarder brake are realized by negative torque output of a motor, and the method comprises the following steps: acquiring road information in front of a vehicle; Determining whether the vehicle is in a normal driving area or a long downhill area based on the front road information; When the vehicle brakes in the normal running area, the torque distribution of the plurality of braking sources is executed according to a short-distance braking algorithm, wherein the torque distribution comprises the steps of limiting the braking torque of the hydraulic retarder when the vehicle brakes in the normal running area and a driver pulls down the retarder handle; when the vehicle is braked in the long downhill region, torque distribution of the plurality of brake sources is performed according to a long-distance braking algorithm.
2. 2. The method of claim 1, wherein said performing torque distribution of said plurality of brake sources according to a short range braking algorithm comprises: Under the condition that the vehicle brakes in the normal running area and the driver pulls down the retarder handle, when the current SOC of the battery is more than or equal to the maximum SOC, the total braking torque which can be used by the vehicle is equal to the sum of the mechanical braking torque and the hydraulic retarder braking torque, The hydraulic retarder braking torque is required to meet the requirement that the hydraulic retarder braking torque is smaller than zero and larger than the original hydraulic retarder braking torque determined based on the external hydraulic retarder braking characteristic, the external hydraulic retarder braking characteristic is related to the rotating speed of the hydraulic retarder, and the hydraulic retarder braking torque is limited through the magnitude of a torque coefficient corresponding to the current gear of the retarder handle when the gear of the retarder handle does not reach the highest gear.
3. 3. The method of claim 1, wherein said performing torque distribution of said plurality of brake sources according to a short range braking algorithm comprises: Under the condition that the vehicle brakes in the normal running area and the driver pulls down the retarder handle, when the current SOC of the battery is smaller than the maximum SOC, the total braking torque which can be used by the vehicle is equal to the sum of the mechanical braking torque, the hydraulic retarder braking torque, the electric retarder braking torque and the motor braking torque controlled by a brake pedal, Wherein the motor braking torque is equal to the sum of the electric retarder braking torque and the brake pedal controlled motor braking torque, the motor braking torque is required to satisfy more than a motor raw braking torque determined based on a motor out-of-braking characteristic, the motor out-of-braking characteristic being related to motor speed, and the motor braking torque is required to satisfy less than zero and more than a motor maximum braking torque limited by a battery maximum allowable charge power; The hydraulic retarder braking torque needs to meet the original braking torque of the hydraulic retarder, which is smaller than zero and larger than the original braking torque of the hydraulic retarder, which is determined based on the external characteristics of the hydraulic retarder, wherein the external characteristics of the hydraulic retarder relate to the rotating speed of the hydraulic retarder, the hydraulic retarder braking torque is limited by the magnitude of a torque coefficient corresponding to the current gear of a retarder handle, and the hydraulic retarder is not activated when the retarder handle is in a middle-low gear.
4. 4. The method of claim 3, wherein said performing torque distribution of said plurality of brake sources in accordance with a short range braking algorithm in combination with whether a driver pulls down said retarder handle comprises: In case the vehicle is braked in said normal driving zone, the driver pulls down said retarder handle, and the current SOC of the battery is smaller than said maximum SOC, When the retarder handle is in a high gear, the hydraulic retarder works; When the retarder handle is in a middle-low gear, but when the electric retarder cannot provide enough braking torque in the current gear, the hydraulic retarder is forced to intervene so as to compensate for the part of insufficient braking torque of the electric retarder.
5. 5. The method of claim 1, wherein said performing torque distribution for said plurality of brake sources according to a long range braking algorithm comprises: Calculating the recoverable braking energy of the long downhill when the vehicle brakes in the long downhill region; Calculating the allowable charging energy of the current battery; When the current battery allowable charge energy is smaller than the long downhill recoverable braking energy and a driver pulls down a retarder handle, the total braking torque which can be used by the vehicle is equal to the sum of mechanical braking torque, hydraulic retarder braking torque, electric retarder braking torque and motor braking torque controlled by a brake pedal, and active intervention is carried out on the hydraulic retarder braking torque and the electric retarder braking torque.
6. 6. The method of claim 5, wherein calculating long downhill recoverable braking energy comprises: when the vehicle is braked in the long downhill area, calculating motor recoverable braking power when the vehicle continuously descends at the current speed and is braked only by a motor without using the mechanical brake and the hydraulic retarder; And calculating the recoverable braking energy of the long downhill based on the recoverable braking power of the motor, the braking energy recovery efficiency and other power of the electric devices of the whole vehicle.
7. 7. The method of claim 5, wherein said actively intervening in said hydrodynamic retarder braking torque and said electric retarder braking torque comprises: calculating and continuously updating the recoverable braking energy from the continuous downhill of the electric retarder braking torque of the vehicle under the current retarder gear to the end of the downhill in real time; And if the allowable charging energy of the current battery is smaller than the recyclable braking energy from the continuous downhill to the end of the downhill of the braking torque of the electric retarder, adjusting the braking torque of the electric retarder in the long downhill area.
8. 8. The method of claim 7, wherein said adjusting said electric retarder braking torque of said long downhill region comprises: calculating the minimum available torque of the electric retarder according to the current battery allowable charge energy and an allowable electric energy recovery torque coefficient, wherein the allowable electric energy recovery torque coefficient is related to at least one of the current SOC of the battery, the remaining mileage, the temperature of the hydraulic retarder, the maximum allowable charge power of the battery and the allowable recovery power of the motor; and taking the maximum available torque of the electric retarder and the original braking torque of the electric retarder determined based on the external braking characteristics of the motor as the final braking torque of the electric retarder.
9. 9. The method of claim 8, wherein said actively intervening in said hydrodynamic retarder braking torque and said electric retarder braking torque comprises: When the driver operates the retarder handle to be in a 1-gear, the vehicle enters a constant-speed gear; And controlling the braking torque of the hydrodynamic retarder and the braking torque of the electric retarder according to a constant speed gear control strategy so as to ensure that the speed of the vehicle in the long downhill area is stabilized at a target speed.
10. 10. The method of claim 9, wherein said controlling said hydrodynamic retarder braking torque and said electric retarder braking torque in accordance with a constant speed gear control strategy comprises: Calculating the minimum braking torque available for the current electric retarder and the hydraulic retarder; Controlling the total target torque of the electric retarder and the hydraulic retarder corresponding to the retarder according to the deviation of the current vehicle speed and the constant speed gear control vehicle speed, wherein the constant speed gear control vehicle speed is the vehicle speed when a driver releases a throttle or brakes, and the total target torque of the electric retarder and the hydraulic retarder is not less than the minimum total target torque of the electric retarder and the hydraulic retarder; Taking the maximum available torque of the electric retarder, the original braking torque of the electric retarder determined based on the external braking characteristics of the motor and the minimum value of the total target torque of the electric retarder and the hydraulic retarder as the final braking torque of the electric retarder; and subtracting the final braking torque of the electric retarder from the total target torque of the electric retarder and the hydraulic retarder to obtain the final braking torque of the hydraulic retarder.
11. 11. The method of any one of claims 4, 8 and 10, wherein said performing torque distribution of said plurality of brake sources comprises: Detecting the actual feedback braking torque of the current gear of the hydrodynamic retarder; Determining whether the braking torque of the hydrodynamic retarder is limited or not based on the actual feedback braking torque of the current gear of the hydrodynamic retarder; When the braking torque of the hydraulic retarder is limited, transferring the limited braking torque part of the hydraulic retarder to the electric retarder; detecting the actual feedback braking torque of the current gear of the electric retarder after the hydraulic retarder is detected; determining whether the electric retarder braking torque is limited based on the actual feedback braking torque of the current gear of the electric retarder; And when the electric retarder braking torque is determined to be limited, transferring the limited part of the electric retarder braking torque to the electric retarder.
12. 12. The method of claim 11, wherein said determining whether said hydrodynamic retarder braking torque is limited based on an actual feedback braking torque of a current gear of said hydrodynamic retarder comprises: when the deviation between the actual feedback braking torque of the current gear of the hydrodynamic retarder and the braking torque of the hydrodynamic retarder is not larger than a braking torque deviation threshold value of the hydrodynamic retarder, determining that the braking torque of the hydrodynamic retarder is not limited; When the deviation between the actual feedback braking torque of the current gear of the hydrodynamic retarder and the braking torque of the hydrodynamic retarder is larger than the deviation threshold value of the braking torque of the hydrodynamic retarder, determining that the braking torque of the hydrodynamic retarder is limited, The determining whether the electric retarder braking torque is limited based on the actual feedback braking torque of the current gear of the electric retarder comprises: when the deviation between the actual feedback braking torque of the current gear of the electric retarder and the braking torque of the electric retarder is not larger than a motor braking torque deviation threshold value, determining that the braking torque of the electric retarder is not limited; And when the deviation between the actual feedback braking torque of the current gear of the electric retarder and the braking torque of the electric retarder is larger than the motor braking torque deviation threshold value, determining that the braking torque of the electric retarder is limited.
13. 13. The method according to claim 12, wherein, in case the hydrodynamic retarder braking torque is limited, the determining whether the electric retarder braking torque is limited based on the actual feedback braking torque of the electric retarder current gear comprises: And determining whether the braking torque of the electric retarder after the limited torque is transferred to the electric retarder by the hydraulic retarder is limited or not based on the actual feedback braking torque of the current gear of the electric retarder.
14. 14. A vehicle compound brake control system comprising a memory, a processor and a computer program stored on the memory, wherein the processor executes the computer program to implement the steps of the vehicle compound brake control method as claimed in any one of claims 1 to 13.
15. 15. A vehicle comprising a vehicle multiple brake control system according to claim 14.

Description

Vehicle composite braking control method and system and vehicle Technical Field The application relates to the technical field of vehicles, in particular to a vehicle composite braking control method and system and a vehicle. Background Because the pure electric vehicle cannot recover braking energy after the battery is fully charged, the pure electric vehicle needs to rely on the mechanical braking of a brake disc seriously when the vehicle runs down a long slope, but the braking performance can be degraded due to long-time mechanical braking. In order to solve the problem, a hydraulic retarder is installed on a vehicle, and the hydraulic retarder can solve the problem of braking, but the energy of the hydraulic retarder cannot be recovered generally, and the high-frequency use of the hydraulic retarder can cause the increase of energy consumption. Disclosure of Invention An object of an embodiment of the present application is to provide a vehicle composite brake control method and system, and a vehicle, which can solve at least one technical problem mentioned in the prior art. One aspect of the embodiments of the present application provides a vehicle compound brake control method. The vehicle includes a plurality of braking sources. The multiple braking sources comprise mechanical braking, hydraulic retarder braking, motor braking controlled by a brake pedal and electric retarder braking, the electric retarder and the hydraulic retarder are controlled by retarder handles, and the motor braking controlled by the brake pedal and the electric retarder braking are realized by negative torque output by a motor. The method comprises the steps of obtaining road information in front of a vehicle, determining whether the vehicle is in a normal running area or a long downhill area based on the road information in front of the vehicle, and executing torque distribution of the plurality of braking sources according to a short-distance braking algorithm when the vehicle is braked in the normal running area, wherein the method comprises the steps of limiting braking torque of the hydraulic retarder when the vehicle is braked in the normal running area and a driver pulls down a retarder handle, and executing torque distribution of the plurality of braking sources according to a long-distance braking algorithm when the vehicle is braked in the long downhill area. Further, the performing of the torque distribution of the plurality of braking sources according to the short-range braking algorithm includes that when the vehicle is braked in the normal driving area and the driver pulls down the retarder handle, the total braking torque which the vehicle can use is equal to the sum of the mechanical braking torque and the hydrodynamic retarder braking torque when the current SOC of the battery is greater than or equal to the maximum SOC, wherein the hydrodynamic retarder braking torque needs to satisfy a hydrodynamic retarder original braking torque which is smaller than zero and larger than a hydrodynamic retarder original braking torque determined based on a hydrodynamic retarder brake external characteristic, the hydrodynamic retarder brake external characteristic is related to the hydrodynamic retarder rotation speed, and the hydrodynamic retarder braking torque is limited by the magnitude of a torque coefficient corresponding to the current gear of the retarder handle when the gear of the retarder handle does not reach the highest gear. Further, the performing of the torque distribution of the plurality of brake sources according to the short-range braking algorithm comprises that when the vehicle is braked in the normal driving zone and the driver pulls down the retarder handle, the total braking torque that the vehicle can use is equal to the sum of the mechanical braking torque, the hydrodynamic retarder braking torque, the electric retarder braking torque and the brake pedal controlled motor braking torque when the current SOC of the battery is smaller than the maximum SOC, wherein the motor braking torque is equal to the sum of the electric retarder braking torque and the brake pedal controlled motor braking torque, the motor braking torque needs to satisfy a motor original braking torque that is determined based on a motor external braking characteristic that is related to a motor rotational speed, and the motor braking torque needs to satisfy a motor maximum braking torque that is smaller than zero and larger than a hydrodynamic retarder original braking torque determined based on a hydrodynamic retarder external braking characteristic that is related to a hydrodynamic retarder rotational speed, and the hydrodynamic retarder is not in the low hydraulic brake torque limit when the current retarder position is not in the low brake torque limit. Further, the torque distribution of the plurality of braking sources according to a short-range braking algorithm in combination with whether the driver pulls down the reta