A vehicle and a regenerative braking assistance control method and system thereof
By obtaining the difference between the regenerative braking requested power and the battery's allowed recharge power, the engine exhaust braking and drive motor regenerative braking are controlled, and the engine speed is adjusted. This solves the problem of insufficient regenerative braking in new energy vehicles when the battery is fully charged or at low temperatures, achieving energy consumption reduction and consistent braking feel, and ensuring vehicle safety and energy utilization efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHENGZHOU YUTONG BUS CO LTD
- Filing Date
- 2023-02-07
- Publication Date
- 2026-08-04
AI Technical Summary
New energy vehicles have limited battery recharge capacity when the battery is fully charged or in low temperatures, which leads to weakened regenerative braking, increased energy consumption, inconsistent braking feel, and may cause mechanical braking overheating and regenerative braking failure when going downhill for a long time.
By obtaining the difference between the regenerative braking requested power and the battery's allowed recharge power, the engine exhaust braking and drive motor regenerative braking are controlled, and the engine speed is adjusted to achieve regenerative braking auxiliary control, including closing the exhaust brake valve and using the generator to drive the engine for kinetic energy conversion.
It solves the problem of insufficient regenerative braking caused by limited battery recharge capacity, reduces energy consumption, ensures consistent braking feel, avoids regenerative braking failure on long downhill sections, and improves vehicle braking safety and energy utilization efficiency.
Smart Images
Figure CN116653615B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a vehicle and its regenerative braking auxiliary control method and system, belonging to the fields of new energy regenerative braking systems and engine exhaust braking technology. Background Technology
[0002] New energy vehicles utilize regenerative braking, where the drive motor applies reverse braking torque to convert kinetic energy into electrical energy, which is then stored in the battery. Regenerative braking has become a crucial energy-saving technology for new energy vehicles and can also reduce brake pad wear. However, under conditions such as a fully charged battery or low temperatures, the battery's recharge capacity is limited, leading to weakened or unusable regenerative braking. This results in increased energy consumption, inconsistent braking feel, and, during prolonged downhill driving, overheating of the mechanical brakes, causing brake reduction and potentially leading to accidents.
[0003] Currently, new energy range-extended vehicles mainly use a compound braking method to address the problem of weakened regenerative braking. This involves adjusting the mechanical braking to supplement the reduced regenerative braking force, while maintaining a consistent braking feel. However, regenerative braking and mechanical braking operate on different principles. Compound braking cannot guarantee 100% braking consistency, and prolonged mechanical braking can cause brake fade, leading to reduced vehicle braking performance. Summary of the Invention
[0004] The purpose of this invention is to provide a vehicle and its regenerative braking auxiliary control method and system to solve the problems of weakened regenerative braking, increased vehicle energy consumption, and inconsistent braking caused by the limited recharge capacity of the vehicle battery.
[0005] To achieve the above objectives, the present invention includes:
[0006] A vehicle regenerative braking auxiliary control method of the present invention includes the following steps:
[0007] 1) When the vehicle brakes, obtain the regenerative braking request power and the battery's allowed recharge power;
[0008] 2) When the regenerative braking request power is greater than or equal to the battery's allowable recharge power, the engine exhaust braking power and the drive motor regenerative braking power are determined based on the difference between the regenerative braking request power and the battery's allowable recharge power. The drive motor is controlled to perform regenerative braking according to the determined regenerative braking power, and the exhaust braking valve is closed. The generator is controlled to drive the engine so that the engine speed reaches the speed value corresponding to the engine exhaust braking power.
[0009] Beneficial effects: The vehicle regenerative braking auxiliary control method of the present invention, when the regenerative braking request power is greater than or equal to the battery's allowable recharge power, drives the motor to perform regenerative braking, converting the vehicle's kinetic energy into electrical energy, and closes the exhaust brake valve, increasing the engine's internal resistance. Then, the generator drives the engine to supplement the vehicle's regenerative braking by consuming electricity, so that the engine speed reaches the set value corresponding to the engine's exhaust braking power. This solves the problem of insufficient regenerative braking caused by the limited battery recharge capacity when the battery is fully charged or at low temperature, reduces energy consumption, and avoids problems such as inconsistent braking feel and regenerative braking failure on long downhill slopes.
[0010] Furthermore, when the difference between the regenerative braking requested power and the battery's allowable recharge power is less than or equal to the minimum power when the engine exhaust braking is operating, the engine speed corresponding to the minimum power operation of the engine exhaust braking is controlled, and the regenerative braking power of the drive motor is made equal to the regenerative braking requested power.
[0011] Beneficial effects: By comparing the difference between the regenerative braking requested power and the battery's allowed recharge power with the minimum power when the engine exhaust braking is working, and based on the fact that the difference between the regenerative braking requested power and the battery's allowed recharge power is less than or equal to the minimum power when the engine exhaust braking is working, the engine speed corresponding to the minimum power when the engine exhaust braking is working is controlled, so that the exhaust braking can save electricity and solve the problem of excessive power consumption of exhaust braking leading to energy consumption.
[0012] Furthermore, when the difference between the regenerative braking requested power and the battery's allowed recharge power is greater than the maximum power when the engine exhaust braking is working, the engine speed corresponding to the engine exhaust braking working at maximum power is controlled, and the regenerative braking power of the drive motor is made equal to the sum of the battery's allowed power and the maximum power when the engine exhaust braking is working.
[0013] Beneficial effects: By comparing the difference between the regenerative braking request power and the battery's allowable recharge power with the maximum power when the engine exhaust braking is working, the engine speed corresponding to the maximum power of the engine exhaust braking is controlled, so that the exhaust braking can save electricity and solve the problem of excessive power consumption caused by exhaust braking.
[0014] Furthermore, when the difference between the regenerative braking requested power and the battery's allowable recharge power is within the engine exhaust braking power limit range, the exhaust braking power value is controlled to be equal to the difference between the regenerative braking requested power and the battery's allowable recharge power. The engine exhaust braking is controlled to operate at the engine speed corresponding to the exhaust braking power value, and the regenerative braking power of the drive motor is made equal to the regenerative braking requested power.
[0015] Beneficial effects: When the difference between the regenerative braking requested power and the battery's allowable recharge power is within the engine exhaust braking power limit, the exhaust braking power value is controlled to be equal to the difference between the regenerative braking requested power and the battery's allowable recharge power. The generator can adjust the engine exhaust braking speed according to different power demands, maximize the use of battery recharge, save vehicle energy consumption, and ensure vehicle braking safety.
[0016] Furthermore, the regenerative braking request power is determined based on the depth of the brake pedal.
[0017] This invention discloses a vehicle regenerative braking auxiliary control system. The system acquires a brake opening signal and a battery recharge signal. It processes the brake opening signal to obtain a regenerative braking request power and processes the battery recharge signal to obtain a battery rechargeable power. When the regenerative braking request power is greater than or equal to the battery rechargeable power, it determines the engine exhaust braking power and the drive motor regenerative braking power based on the difference between the regenerative braking request power and the battery rechargeable power. It generates a drive motor control signal to control the drive motor to perform regenerative braking according to the determined regenerative braking power, generates an engine exhaust braking valve control signal to control the engine exhaust braking valve to close, and generates a generator control signal based on the determined engine exhaust braking power to control the generator to drive the engine, causing the engine speed to reach the speed value corresponding to the engine exhaust braking power.
[0018] Beneficial Effects: The vehicle regenerative braking auxiliary control system of the present invention compares the requested regenerative braking power with the allowed battery recharge power. When the requested regenerative braking power is greater than or equal to the allowed battery recharge power, the drive motor is controlled to perform regenerative braking, converting the vehicle's kinetic energy into electrical energy. The engine's exhaust brake valve is closed, increasing the engine's internal resistance. The generator is then controlled to drive the engine, consuming electricity to supplement the vehicle's regenerative braking, bringing the engine speed to the set value corresponding to the engine's exhaust brake power. This system solves the problem of insufficient regenerative braking caused by limited battery recharge capacity when the battery is fully charged or at low temperatures. It also reduces energy consumption and avoids problems such as inconsistent braking feel and regenerative braking failure on long downhill slopes.
[0019] Furthermore, when the difference between the regenerative braking requested power and the battery's allowable recharge power is less than or equal to the minimum power when the engine exhaust braking is working, the engine speed corresponding to the minimum power when the engine exhaust braking is working is controlled, and the regenerative braking power of the drive motor is made equal to the regenerative braking requested power.
[0020] Beneficial effects: By comparing the difference between the regenerative braking requested power and the battery's allowed recharge power with the minimum power when the engine exhaust braking is working, and based on the fact that the difference between the regenerative braking requested power and the battery's allowed recharge power is less than or equal to the minimum power when the engine exhaust braking is working, the engine speed corresponding to the minimum power when the engine exhaust braking is working is controlled, so that the exhaust braking can save electricity and solve the problem of excessive power consumption of exhaust braking leading to energy consumption.
[0021] Furthermore, when the difference between the regenerative braking requested power and the battery's allowed recharge power is greater than the maximum power when the engine exhaust braking is working, the engine speed corresponding to the engine exhaust braking working at maximum power is controlled, and the regenerative braking power of the drive motor is made equal to the sum of the battery's allowed power and the maximum power when the engine exhaust braking is working.
[0022] Beneficial effects: By comparing the difference between the regenerative braking request power and the battery's allowable recharge power with the maximum power when the engine exhaust braking is working, the engine speed corresponding to the maximum power of the engine exhaust braking is controlled, so that the exhaust braking can save electricity and solve the problem of excessive power consumption caused by exhaust braking.
[0023] Furthermore, when the difference between the regenerative braking requested power and the battery's allowable recharge power is within the engine exhaust braking power limit range, the exhaust braking power value is controlled to be equal to the difference between the regenerative braking requested power and the battery's allowable recharge power. The engine exhaust braking is controlled to operate at the engine speed corresponding to the exhaust braking power value, and the regenerative braking power of the drive motor is made equal to the regenerative braking requested power.
[0024] Beneficial effects: When the difference between the regenerative braking requested power and the battery's allowable recharge power is within the engine exhaust braking power limit, the exhaust braking power value is controlled to be equal to the difference between the regenerative braking requested power and the battery's allowable recharge power. The generator can adjust the engine exhaust braking speed according to different power demands, maximize the use of battery recharge, save vehicle energy consumption, and ensure vehicle braking safety.
[0025] A vehicle according to the present invention includes an engine, a generator, a drive motor, a battery management system, and a power battery. The engine is connected to the generator, the generator is connected to the drive motor, the drive motor is used to drive the vehicle, and the battery management system is used to acquire state data of the power battery. The vehicle is characterized in that it further includes a regenerative braking assist control system, which is used to connect the drive motor, the battery management system, the brake pedal, the engine, and the generator. The regenerative braking assist control system is as described above.
[0026] Beneficial effects: The vehicle of the present invention, in addition to the existing device, also includes a regenerative braking assist control system. This system can effectively solve the problem of insufficient regenerative braking caused by the limited battery recharge capacity, while reducing energy consumption and avoiding problems such as inconsistent braking feel and regenerative braking failure during long downhill sections. Attached Figure Description
[0027] Figure 1 This is a control flowchart of the regenerative braking assist system in an embodiment of the method of the present invention;
[0028] Figure 2 This is a schematic diagram of the regenerative braking assist system in a vehicle embodiment of the present invention. Detailed Implementation
[0029] The present invention will now be described in further detail with reference to the accompanying drawings.
[0030] Example of a vehicle regenerative braking auxiliary control method:
[0031] like Figure 1 The method described is a vehicle regenerative braking auxiliary control method. When the vehicle brakes, it compares the requested electric braking power with the battery's allowed recharge power to determine whether to initiate auxiliary control regenerative braking. When auxiliary control regenerative braking is activated, the engine exhaust brake butterfly valve is closed, increasing the engine's internal resistance. This causes the generator to drive the engine, consuming power exceeding the battery's recharge capacity. Based on the required braking power, the engine speed is continuously adjusted to maximize battery recharge utilization. The specific implementation method is as follows:
[0032] 1. When the vehicle is in motion, after the brake pedal is depressed, the regenerative braking request power P is obtained. Brk and battery allowable recharge power P Charge .
[0033] The regenerative braking power request is determined by the depth of the brake pedal. The deeper the brake pedal is pressed, the greater the regenerative braking power request, and vice versa.
[0034] 2. When the regenerative braking request power is greater than or equal to the battery's allowable recharge power, the drive motor performs regenerative braking and closes the exhaust brake valve. The engine exhaust brake power is controlled according to the difference between the regenerative braking request power and the battery's allowable recharge power. The generator drives the engine to make the engine speed reach the set value corresponding to the engine exhaust brake power.
[0035] When the regenerative braking requested power is less than the battery's allowable recharge power (P) Brk <P ChargeWhen the regenerative braking auxiliary control is not performed, only regenerative braking is performed, and the regenerative braking power is equal to the regenerative braking request power P. Brk equal.
[0036] When the regenerative braking requested power is greater than or equal to the battery's allowable recharge power (P) Brk ≥P Charge When this occurs, the regenerative braking auxiliary control system is activated to provide auxiliary control for regenerative braking.
[0037] When the regenerative braking auxiliary control system is activated to perform auxiliary control of regenerative braking, the difference between the requested regenerative braking power and the battery's allowable recharge power (P) is compared. Brk -P Charg ) and engine exhaust braking power (P Eng )size.
[0038] Specifically, when the difference between the regenerative braking requested power and the battery's allowed recharge power is less than or equal to the minimum power (P) when the engine exhaust braking is operating. Brk -P Charg ≤P Eng-MIN When the exhaust brake butterfly valve is closed, the engine's internal resistance is increased. The generator (in this embodiment, the generator is an ISG) drives the engine to perform exhaust brake, replenishing the battery's recharge energy, and bringing the engine speed to the minimum speed Spd corresponding to the minimum power required for the engine's exhaust brake operation. Eng-MIN The generator is driven to perform regenerative braking, and the regenerative braking power of the drive motor is equal to the regenerative braking request power P. Brk equal.
[0039] When the difference between the regenerative braking requested power and the battery's allowed recharge power is within the power limit for engine exhaust braking (P... Eng-MIN ≤P Brk -P Charg ≤P Eng-MAX When the exhaust brake butterfly valve is closed, the ISG generator drives the engine to apply exhaust brake, bringing the speed to Spd. Eng Control the engine exhaust braking power P Eng-Brk The regenerative braking power is equal to the difference between the regenerative braking demand power and the battery's allowable recharge power. The generator adjusts the engine exhaust braking speed according to different power demands, driving the motor to perform regenerative braking, ensuring that the regenerative braking power of the drive motor equals the regenerative braking demand power P. Brk .
[0040] When the difference between the regenerative braking requested power and the battery's allowable recharge power is greater than the maximum power (P) when the engine exhaust braking is engaged... Brk -P Charg >P Eng-MAXWhen the exhaust brake butterfly valve is closed, the ISG lifts the engine to apply exhaust brake, bringing the engine speed to the maximum speed Spd corresponding to the maximum power output during exhaust brake operation. Eng-MAX The drive motor performs regenerative braking, making its regenerative braking power equal to the sum of the battery's allowable recharge power and the engine's maximum power during exhaust braking (P). Charget +P Eng-MAX ).
[0041] Vehicle Example:
[0042] like Figure 2 The vehicle shown includes a regenerative braking assist control system, an engine, a generator, a drive motor, a battery management system, a power battery, a mechanical brake pedal, and a vehicle controller.
[0043] The engine is connected to the vehicle controller, regenerative braking assist control system, and generator, etc. The generator is connected to the vehicle controller, regenerative braking assist control system, and drive motor, etc. The mechanical brake pedal is connected to the regenerative braking assist control system and vehicle controller, etc. The battery management system is connected to the power battery, vehicle controller, regenerative braking assist control system, etc. The power battery is connected to the battery management system and vehicle controller, etc.
[0044] When the vehicle brakes, after the driver presses the brake pedal, the mechanical brake foot valve transmits the brake opening signal to the regenerative braking assist control system. At this time, the battery management system transmits the power battery recharge permission signal to the vehicle controller, and the drive motor transmits signals such as motor speed and motor braking torque to the vehicle controller.
[0045] The regenerative braking assist control system can be located within the vehicle controller or connected to it. In this embodiment, the regenerative braking assist control system is located within the vehicle controller. This system can connect to the battery management system, mechanical brake foot valve, generator, engine, and drive motor. It receives brake opening signals from the brake foot valve, battery recharge permission signals from the battery management system, and motor speed signals from the drive motor. It processes the brake opening signals to obtain the regenerative braking request power and the battery recharge permission signals to obtain the battery recharge permission power. When the regenerative braking request power is greater than or equal to the battery recharge permission power, it determines the engine exhaust braking power and drive motor regenerative braking power based on the difference between the regenerative braking request power and the battery recharge permission power. It generates a drive motor control signal to control the drive motor to perform regenerative braking according to the determined regenerative braking power, generates an engine exhaust brake valve control signal to control the engine exhaust brake valve to close, and generates a generator control signal based on the determined engine exhaust braking power to control the generator to drive the engine, causing the engine speed to reach the speed value corresponding to the engine exhaust braking power. Specific implementation steps have been described in detail in the vehicle regenerative braking assist control method embodiment and will not be repeated here.
[0046] Example of a vehicle regenerative braking assist control system:
[0047] like Figure 2 The present invention relates to a vehicle regenerative braking assist control system, which has been described in detail in the vehicle embodiment. The specific implementation process is described in detail in the vehicle regenerative braking assist control method embodiment and the vehicle embodiment, and will not be repeated here.
Claims
1. A vehicle regenerative braking auxiliary control method, characterized in that, The vehicle is a new energy range-extended vehicle, and the following steps are included: 1) When the vehicle brakes, obtain the regenerative braking request power and the battery's allowed recharge power; 2) When the regenerative braking requested power is greater than or equal to the battery's allowable recharge power, the engine exhaust braking power and the drive motor regenerative braking power are determined based on the difference between the regenerative braking requested power and the battery's allowable recharge power. The drive motor is controlled to perform regenerative braking according to the determined regenerative braking power, and the exhaust braking valve is closed. The generator is controlled to drive the engine, so that the engine speed reaches the speed value corresponding to the engine exhaust braking power. The speed value is greater than or equal to the engine speed corresponding to the engine exhaust braking working at minimum power. When the difference between the regenerative braking requested power and the battery's allowable recharge power is greater than the maximum power when the engine exhaust braking is working, the regenerative braking power of the drive motor is made equal to the sum of the battery's allowable recharge power and the maximum power when the engine exhaust braking is working.
2. The vehicle regenerative braking auxiliary control method according to claim 1, characterized in that, When the difference between the regenerative braking requested power and the battery's allowable recharge power is less than or equal to the minimum power when the engine exhaust braking is working, the engine speed corresponding to the minimum power when the engine exhaust braking is working is controlled, and the regenerative braking power of the drive motor is made equal to the regenerative braking requested power.
3. The vehicle regenerative braking auxiliary control method according to claim 2, characterized in that, When the difference between the regenerative braking requested power and the battery's allowed recharge power is greater than the maximum power when the engine exhaust braking is working, the engine speed corresponding to the maximum power when the engine exhaust braking is working is controlled.
4. The vehicle regenerative braking auxiliary control method according to claim 1, characterized in that, When the difference between the regenerative braking requested power and the battery's allowable recharge power is within the engine exhaust braking power limit, the exhaust braking power value is controlled to be equal to the difference between the regenerative braking requested power and the battery's allowable recharge power. The engine exhaust braking is controlled to operate at the engine speed corresponding to the exhaust braking power value, and the regenerative braking power of the drive motor is made equal to the regenerative braking requested power.
5. The vehicle regenerative braking auxiliary control method according to any one of claims 1-4, characterized in that, The regenerative braking power request is determined based on the depth of the brake pedal.
6. A vehicle regenerative braking assist control system, characterized in that, The vehicle is a new energy range-extended vehicle. The auxiliary control system acquires the brake opening signal and the battery recharge signal. It processes the brake opening signal to obtain the regenerative braking request power and processes the battery recharge signal to obtain the battery's allowed recharge power. When the regenerative braking request power is greater than or equal to the battery's allowed recharge power, it determines the engine exhaust braking power and the drive motor regenerative braking power based on the difference between the regenerative braking request power and the battery's allowed recharge power. It generates a drive motor control signal to control the drive motor to perform regenerative braking according to the determined regenerative braking power, generates an engine exhaust braking valve control signal to control the engine exhaust braking valve to close, and generates a generator control signal based on the determined engine exhaust braking power to control the generator to drive the engine, causing the engine speed to reach the speed value corresponding to the engine exhaust braking power. This speed value is greater than or equal to the engine speed corresponding to the engine exhaust braking operating at minimum power. When the difference between the regenerative braking request power and the battery's allowed recharge power is greater than the maximum power when the engine exhaust braking is operating, it makes the drive motor's regenerative braking power equal to the sum of the battery's allowed recharge power and the engine exhaust braking's maximum power.
7. The vehicle regenerative braking assist control system according to claim 6, characterized in that, When the difference between the regenerative braking requested power and the battery's allowable recharge power is less than or equal to the minimum power when the engine exhaust braking is working, the engine speed corresponding to the minimum power when the engine exhaust braking is working is controlled, and the regenerative braking power of the drive motor is made equal to the regenerative braking requested power.
8. The vehicle regenerative braking assist control system according to claim 6, characterized in that, When the difference between the regenerative braking requested power and the battery's allowable recharge power is within the engine exhaust braking power limit, the exhaust braking power value is controlled to be equal to the difference between the regenerative braking requested power and the battery's allowable recharge power. The engine exhaust braking is controlled to operate at the engine speed corresponding to the exhaust braking power value, and the regenerative braking power of the drive motor is made equal to the regenerative braking requested power.
9. The vehicle regenerative braking assist control system according to claim 6, characterized in that, When the difference between the regenerative braking requested power and the battery's allowed recharge power is greater than the maximum power when the engine exhaust braking is working, the engine speed corresponding to the maximum power when the engine exhaust braking is working is controlled.
10. A vehicle comprising an engine, a generator, a drive motor, a battery management system, and a power battery, wherein the engine is connected to the generator, the generator is connected to the drive motor, the drive motor is used to drive the vehicle, and the battery management system is used to acquire state data of the power battery, characterized in that, It also includes a regenerative braking assist control system, which is used to connect the drive motor, the battery management system, the brake pedal, the engine and the generator, and the regenerative braking assist control system is the regenerative braking assist control system as described in any one of claims 6-9.