A braking energy recovery device and method for a multi-motor multi-gear heavy commercial vehicle

Abstract

The present invention discloses a braking energy recovery device and method for a multi-motor multi-gear heavy commercial vehicle, belonging to the field of new energy heavy commercial vehicles. The device of the present invention includes a mechanical friction braking system and a braking energy recovery electric braking system; the method of the present invention includes the following steps: identifying the braking intention of the driver and judging whether it is an emergency braking; taking the braking safety and stability of the vehicle as constraint conditions, performing braking force distribution among the steering axle, the front electric drive axle, the rear electric drive axle and the trailer axle; detecting and estimating whether the state of charge (SOC) of the battery is greater than or equal to 0.95; on the premise of safe braking, with the goal of maximizing the recovered braking energy, calculating and determining the electric braking force and the mechanical braking force of the front electric drive axle and the rear electric drive axle respectively. The braking energy recovery device and method for the multi-motor multi-gear electric heavy commercial vehicle of the present invention can increase the vehicle's cruising range on the premise of ensuring safety.

Description

Technical Field

[0001] The present invention belongs to the field of new energy heavy commercial vehicles, and particularly relates to a braking energy recovery device and method for a multi-motor multi-gear heavy commercial vehicle. Background Art

[0002] Fuel heavy commercial vehicles consume a large amount of fuel and emit a lot of pollutants. Electrification is an effective way to solve these problems, while the cruising range of electric heavy commercial vehicles is relatively short. The traditional friction braking of heavy commercial vehicles wastes the kinetic energy of the vehicle by converting it into heat, while the braking energy recovery technology can convert part of the kinetic energy of the vehicle into electrical energy for storage, thereby improving the energy utilization rate and increasing the cruising range of the vehicle.

[0003] Heavy commercial vehicles have a large range of power requirements. Their electric drive systems need to be equipped with multiple motors and multi-gear transmissions, and arranged on two drive axles to meet the vehicle's power requirements and improve the vehicle's economy. In addition, in addition to tractors, heavy commercial vehicles usually also include trailers. The braking systems of traditional heavy commercial vehicles are equipped with pneumatic braking systems on each axle of the tractor and trailer, and each wheel can provide braking force.

[0004] With the rapid development of motor control technology, the motors on new energy vehicles can be selected to operate in the motor state or the generator state according to the needs of the vehicle driving conditions, and can output the target driving torque or electric braking torque according to the requirements. On the one hand, it enables the vehicle to have good driving performance, and on the other hand, under braking conditions, the vehicle can convert part of the braking energy into electrical energy to charge the battery.

[0005] Electric heavy commercial vehicles are mostly used for medium and short-distance logistics transportation, and there are many braking conditions. Braking energy recovery plays an important role in improving its energy utilization rate and increasing the cruising range of the vehicle. Braking energy recovery relies on technologies such as driver intention recognition, motor control, and transmission control. Summary of the Invention

[0006] Aiming at the above technical problems existing in the prior art, the present invention proposes a braking energy recovery device and method for a multi-motor multi-gear heavy commercial vehicle, which is reasonably designed, overcomes the deficiencies of the prior art, and has good effects.

[0007] To achieve the above object, the present invention adopts the following technical solution: A braking energy recovery device for a multi-motor multi-gear heavy commercial vehicle, comprising a mechanical friction braking system and a braking energy recovery electric braking system; The multi-motor multi-gear heavy commercial vehicle includes two drive axles, one of the drive axles includes two motors and a three-speed transmission, and the other drive axle includes one motor and a two-speed transmission; The mechanical friction braking system includes a brake pedal, a brake controller and a pneumatic braking system; wherein, the brake pedal is configured to obtain the braking operation of the driver; the brake controller is configured to control the pneumatic braking system according to the vehicle controller instruction; the pneumatic braking system is configured to provide air pressure for each braking wheel brake; Each braking wheel includes two wheels of the tractor steering axle, two wheels of the front electric drive axle, two wheels of the rear electric drive axle, and each wheel of the tractor; The braking energy recovery electric braking system includes a battery, a motor controller, a dual-motor three-speed drive system of the front electric drive axle, and a single-motor two-speed electric drive system of the rear electric drive axle; The battery is configured to store and release electric energy; the motor controller is configured to control the motor; the dual-motor three-speed drive system of the front electric drive axle is configured to provide driving force and braking force for the heavy commercial vehicle; the single-motor two-speed electric drive system of the rear electric drive axle is configured to provide driving force and braking force for the heavy commercial vehicle.

[0008] In addition, the present invention also mentions a braking energy recovery method for a multi-motor multi-gear heavy commercial vehicle. This method uses a braking energy recovery device for a multi-motor multi-gear heavy commercial vehicle as described above, and specifically includes the following steps: S1: According to the depth and change speed of the brake pedal, determine whether the driver's braking intention is emergency braking or non-emergency braking. If it is emergency braking, execute step S2; if it is non-emergency braking, execute step S3; S2: Apply braking with the maximum braking force. Through the pneumatic braking system, provide decision-making braking force for the brake controller, and activate the anti-lock braking system to control the braking forces of the steering axle, front electric drive axle, rear electric drive axle, and trailer axle of the heavy commercial vehicle; S3: Through the brake controller, calculate and determine the total required braking force of the heavy commercial vehicle according to the driver's braking intention and the current vehicle state; S4: With the vehicle braking safety and stability as constraints, distribute the braking force among the steering axle, front electric drive axle, rear electric drive axle, and trailer axle, and detect and estimate whether the battery SOC is greater than or equal to 0.95. If the battery SOC is greater than or equal to 0.95, execute step S5; if the battery SOC is less than 0.95, execute step S6; S5: Through the pneumatic braking system, provide braking force for the steering axle, front electric drive axle, rear electric drive axle, and trailer axle of the heavy commercial vehicle; S6: Through the pneumatic braking system, provide braking force for the brake controller to make decisions on the steering axle and trailer axle of the heavy commercial vehicle; S7: Through the brake controller, on the premise of safe braking, with the goal of recovering the most braking energy, calculate and determine the electric braking force and mechanical braking of the front electric drive axle and the rear electric drive axle respectively.

[0009] Preferably, the braking energy recovery electric braking system participates in the braking of the heavy commercial vehicle during non-emergency braking and when the battery SOC is lower than 0.95.

[0010] Preferably, when the braking energy recovery electric braking system participates in braking, if the vehicle speed decreases, the voltage generated by the braking energy recovery electric braking system decreases. When this voltage is lower than the charging voltage required by the battery, the three-speed transmission of the front electric drive axle and the two-speed transmission of the rear electric drive axle downshift to increase the voltage generated by the braking energy recovery electric braking system and continue to charge the battery; when the three-speed transmission of the front electric drive axle and the two-speed transmission of the rear electric drive axle are both operating in their first gears and the vehicle speed is lower than 7 km / h, the braking energy recovery electric braking system no longer provides braking force, and all braking forces are provided by the mechanical friction braking system.

[0011] The beneficial technical effects brought by the present invention: The braking energy recovery device and method for the multi-motor multi-gear electric heavy commercial vehicle of the present invention can increase the vehicle's cruising range on the premise of ensuring safety. Description of the Drawings

[0012] Figure 1Schematic diagram of the composition of the braking energy recovery device for a multi-motor multi-gear heavy commercial vehicle according to the present invention.

[0013] Figure 2 Schematic diagram of the configuration of the electric drive system for a multi-motor multi-gear heavy commercial vehicle according to the present invention.

[0014] Figure 3 Basic flowchart of the braking energy recovery method according to the present invention. Specific embodiments

[0015] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments: Embodiment 1: As Figure 1 shown, a braking energy recovery device for a multi-motor multi-gear heavy commercial vehicle includes a mechanical friction braking system and a braking energy recovery electric braking system; the multi-motor multi-gear heavy commercial vehicle includes two drive axles, one of which includes two motors and a three-speed transmission, and the other drive axle includes one motor and a two-speed transmission; the mechanical friction braking system includes a brake pedal, a brake controller, and a pneumatic braking system; wherein, the brake pedal is configured to obtain the braking operation of the driver; the brake controller is configured to control the pneumatic braking system according to the vehicle controller instruction; the pneumatic braking system is configured to provide air pressure for each braking wheel brake; each braking wheel includes two wheels of the tractor steering axle, two wheels of the front electric drive axle, two wheels of the rear electric drive axle, and each wheel of the tractor; the braking energy recovery electric braking system includes a battery, a motor controller, a dual-motor three-speed drive system of the front electric drive axle, and a single-motor two-speed electric drive system of the rear electric drive axle; the battery is configured to store and release electric energy; the motor controller is configured to control the motor; the dual-motor three-speed drive system of the front electric drive axle is configured to provide driving force and braking force for the heavy commercial vehicle; the single-motor two-speed electric drive system of the rear electric drive axle is configured to provide driving force and braking force for the heavy commercial vehicle.

[0016] Figure 2 The basic configuration schemes of the dual-motor three-speed electric drive system of the front electric drive axle and the single-motor two-speed electric drive system of the rear electric drive axle are given; when the front electric drive axle and the rear electric drive axle need to provide electric braking force, Motors 1, 2, and 3 are controlled to operate in the generator state, and the three-speed transmission and the two-speed transmission are controlled to work in appropriate gears according to the required electric braking force.

[0017] Embodiment 2: On the basis of the above Embodiment 1, the present invention also mentions a braking energy recovery method for a multi-motor multi-gear heavy commercial vehicle, and its process is as Figure 3As shown in the figure, it specifically includes the following steps: S1: According to the depth and change speed of the brake pedal, determine whether the driver's braking intention is emergency braking or non-emergency braking. If it is emergency braking, execute step S2; if it is non-emergency braking, execute step S3; S2: Brake with the maximum braking force, and through the pneumatic braking system, provide the decision-making braking force for the brake controller, and start the anti-lock braking system to control the braking forces of the steering axle, front electric drive axle, rear electric drive axle and trailer axle of the heavy commercial vehicle; S3: Through the brake controller, calculate and determine the total required braking force of the heavy commercial vehicle according to the driver's braking intention and the current vehicle state; S4: With the vehicle braking safety and stability as constraints, distribute the braking force among the steering axle, front electric drive axle, rear electric drive axle and trailer axle, and detect and estimate whether the battery SOC is greater than or equal to 0.95. If the battery SOC is greater than or equal to 0.95, execute step S5; if the battery SOC is less than 0.95, execute step S6; S5: Through the pneumatic braking system, provide braking forces for the steering axle, front electric drive axle, rear electric drive axle and trailer axle of the heavy commercial vehicle; S6: Through the pneumatic braking system, provide braking forces for the brake controller to make decisions on the steering axle and trailer axle of the heavy commercial vehicle; S7: Through the brake controller, on the premise of safe braking, with the goal of maximizing the recovered braking energy, calculate and determine the electric braking force and mechanical braking of the front electric drive axle and the rear electric drive axle respectively.

[0018] The braking energy recovery electric braking system participates in the braking of the heavy commercial vehicle during non-emergency braking and when the battery SOC is lower than 0.95.

[0019] When the braking energy recovery electric braking system participates in braking, if the vehicle speed decreases, the voltage generated by the braking energy recovery electric braking system decreases. When this voltage is lower than the charging voltage required by the battery, the three-speed transmission of the front electric drive axle and the two-speed transmission of the rear electric drive axle downshift to increase the voltage generated by the braking energy recovery electric braking system and continue to charge the battery; when the three-speed transmission of the front electric drive axle and the two-speed transmission of the rear electric drive axle are both operating in their first gears and the vehicle speed is lower than 7 km / h, the braking energy recovery electric braking system no longer provides braking force, and all braking forces are provided by the mechanical friction braking system.

[0020] The braking energy recovery device and method for a multi-motor multi-gear electric heavy commercial vehicle of the present invention can increase the vehicle's cruising range on the premise of ensuring safety.

[0021] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the essence of the present invention should also fall within the protection scope of the present invention.

Claims

1. A braking energy recovery method for a multi-motor and multi-gear heavy commercial vehicle, characterized in that: Specifically, it includes the following steps: S1: According to the depth and change speed of the brake pedal, determine whether the driver's braking intention is emergency braking or non-emergency braking. If it is emergency braking, execute step S2; if it is non-emergency braking, execute step S3; S2: Brake with the maximum braking force. Through the pneumatic braking system, provide the decision-making braking force for the brake controller, and start the anti-lock braking system to control the braking forces of the steering axle, front electric drive axle, rear electric drive axle and trailer axle of the heavy commercial vehicle; S3: Through the brake controller, calculate and determine the total required braking force of the heavy commercial vehicle according to the driver's braking intention and the current vehicle state; S4: With the vehicle braking safety and stability as constraints, distribute the braking force among the steering axle, front electric drive axle, rear electric drive axle and trailer axle, and detect and estimate whether the battery SOC is greater than or equal to 0.

95. If the battery SOC is greater than or equal to 0.95, execute step S5; if the battery SOC is less than 0.95, execute step S6; S5: Through the pneumatic braking system, provide braking force for the steering axle, front electric drive axle, rear electric drive axle and trailer axle of the heavy commercial vehicle; S6: Through the pneumatic braking system, provide braking force for the brake controller to make decisions on the steering axle and trailer axle; S7: Through the brake controller, on the premise of safe braking, with the goal of maximizing the recovery of braking energy, calculate and determine the electric braking force and mechanical braking of the front electric drive axle and the rear electric drive axle respectively; The braking energy recovery electric braking system participates in the braking of the heavy commercial vehicle during non-emergency braking and when the battery SOC is lower than 0.95; When the braking energy recovery electric braking system participates in braking, if the vehicle speed decreases, the voltage generated by the braking energy recovery electric braking system decreases. When this voltage is lower than the charging voltage required by the battery, the three-speed transmission of the front electric drive axle and the two-speed transmission of the rear electric drive axle downshift to increase the voltage generated by the braking energy recovery electric braking system and continue to charge the battery. When the three-speed transmission of the front electric drive axle and the two-speed transmission of the rear electric drive axle are both running in their first gears and the vehicle speed is lower than 7 km / h, the braking energy recovery electric braking system no longer provides braking force, and all braking forces are provided by the mechanical friction braking system.

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