Hybrid vehicle torque distribution control method, device, and vehicle

Abstract

This invention discloses a torque distribution control method for hybrid vehicles, comprising: acquiring the total required torque of the vehicle and the vehicle's current operating mode; allocating the target torque of the engine, the target torque of the generator, and the total torque of the drive motors based on the relationship between the total required torque of the vehicle and the economic torque of the engine, combined with the state of charge of the power battery; acquiring the real-time operating parameters of the front and rear axle drive motors; calculating the optimal torque distribution coefficient of the front and rear axle drive motors based on the total torque of the drive motors, the real-time operating parameters, efficiency weights, and temperature weights; and finally distributing the total torque of the drive motors to the front and rear axle drive motors. This invention introduces a temperature penalty factor mechanism to optimize the torque distribution strategy by combining the hybrid vehicle's operating mode and motor temperature changes, ensuring that the power system always operates in a state of optimal overall efficiency, effectively improving the driving range. This invention also discloses a control device and a vehicle.

Description

Technical Field

[0001] This invention belongs to the field of automotive technology. Specifically, this invention relates to a torque distribution control method, device, and vehicle for hybrid vehicles. Background Technology

[0002] Hybrid electric vehicles (HEVs) offer advantages such as energy conservation and emission reduction, range anxiety-free driving, and fast power response. They typically have multiple operating modes, including pure electric, series, and parallel operation. The vehicle's torque distribution strategy is the core of its energy management and directly determines the vehicle's energy consumption and driving range.

[0003] However, existing torque distribution methods are mainly designed for pure electric vehicles and fail to take into account the characteristics of various operating modes of hybrid vehicles. They also ignore the impact of motor temperature characteristics on system efficiency, resulting in limited application scope and difficulty in achieving optimal energy consumption control in hybrid vehicles.

[0004] This invention provides a torque distribution control method for hybrid vehicles, specifically regarding how to optimize the torque distribution strategy by combining the hybrid vehicle's operating mode and motor temperature changes, thereby reducing vehicle energy consumption and effectively improving driving range. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention provides a torque distribution control method for hybrid vehicles, which aims to optimize the torque distribution strategy by combining the hybrid vehicle's operating mode and motor temperature changes, thereby reducing vehicle energy consumption and effectively improving driving range.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a torque distribution control method for hybrid vehicles, comprising: Obtain the total required torque T for the entire vehicle and the current operating mode of the vehicle; Based on the relationship between the total required torque T of the vehicle and the economic torque T1 of the engine, and combined with the state of charge of the power battery, the target torque of the engine, the target torque of the generator and the total torque T2 of the drive motor are allocated. The real-time operating parameters of the front axle drive motor and the rear axle drive motor are obtained, and the real-time operating parameters include at least real-time temperature and real-time efficiency. Based on the total torque T2 of the drive motor, the real-time operating parameters, and the preset efficiency weight and temperature weight, the optimal torque distribution coefficient of the front and rear axle drive motors is calculated. According to the optimal torque distribution coefficient, the total torque T2 of the drive motor is distributed to the front axle drive motor and the rear axle drive motor.

[0007] The vehicle's current operating modes include parallel mode, series mode, and pure electric mode.

[0008] The calculation process for the optimal torque distribution coefficient y includes: Front axle torque distribution coefficient y front The variable is used to iterate within the range of 0 to 1 with a preset step size; For each front axle torque distribution coefficient y encountered during the iteration front Calculate the target torque T of the front axle motor. front and the target torque T of the rear axle motor rear T front =T2*y front T rear =T2*(1-y front ); According to the target torque T of the front axle motor front Target torque T of the rear axle motor rear In addition to the real-time speeds of the front axle drive motor and the rear axle drive motor, the corresponding front axle motor efficiency (eff) is obtained by querying the motor efficiency MAP. front and rear axle motor efficiency rear ; Based on the real-time temperatures of the front axle drive motor and the rear axle drive motor, and the preset temperature limits, calculate the comprehensive temperature penalty factor temp. penalty ; According to the front axle motor efficiency eff front Rear axle motor efficiency rear Comprehensive temperature penalty factor temp penalty Calculate candidate efficiency values ​​using preset efficiency weight η and preset temperature weight α. eff(y) ; Determine the candidate efficiency value. eff(y) The largest distribution coefficient is taken as the optimal torque distribution coefficient y.

[0009] The comprehensive temperature penalty factor temp penalty The calculation process includes: Calculate the front axle motor temperature penalty factor temp penaltyfront =max(0, (front temp -temp limit ) / 10), where front temp temp is the real-time temperature of the front axle drive motor. limit The preset temperature limit value; Calculate the temperature penalty factor temp for the rear axle motor penaltyrear =max(0, (rear temp -temp limit ) / 10), where rear temp This refers to the real-time temperature of the rear axle drive motor. Calculate the comprehensive temperature penalty factor temp penalty =α*(temp penaltyfront +temp penaltyrear ), where α is the preset temperature weight.

[0010] The candidate efficiency value eff(y) The calculation formula is: candidate eff(y) =η*(T front +T rear ) / (T front / eff front +T rear / eff rear )-temp penalty Where η is the preset efficiency weight.

[0011] When the vehicle is in parallel mode and the total required torque of the vehicle T is greater than the economic torque of the engine T1, the target torque of the engine is T1, the target torque of the generator is 0, and the total torque of the drive motor T2 = T - T1.

[0012] When the vehicle is in series mode, the total torque of the drive motor is T2=T, the target torque of the engine is T1, and the target torque of the generator is determined based on the economic torque of the engine T1 and the state of charge of the power battery.

[0013] When the vehicle is in pure electric mode, the target torque of the engine is 0, the target torque of the generator is 0, and the total torque of the drive motor is T2=T.

[0014] The engine's economic torque T1 is determined through the following steps: Obtain fuel consumption rate data of the engine at different speeds; The engine speed range is traversed with a preset step size to determine the torque value with the lowest fuel consumption rate at each speed. Based on the torque value with the lowest fuel consumption rate at each speed, an engine economic torque MAP is generated. Based on the current engine speed, the engine's economic torque T1 is obtained by querying the engine's economic torque MAP.

[0015] The present invention also provides a control device for executing the aforementioned hybrid vehicle torque distribution control method, comprising: The data acquisition module is used to acquire the total required torque T of the vehicle, the current working mode of the vehicle, the state of charge of the power battery, the economic torque T1 of the engine, and the real-time operating parameters of the front axle drive motor and the rear axle drive motor. The real-time operating parameters include at least real-time temperature and real-time efficiency. The first allocation module is used to allocate the target torque of the engine, the target torque of the generator and the total torque of the drive motor T2 according to the relationship between the total demand torque T of the vehicle and the economic torque T1 of the engine, and in combination with the state of charge of the power battery. The second allocation module is used to calculate the optimal torque allocation coefficient y of the front and rear axle drive motors based on the total torque T2 of the drive motor, the real-time operating parameters, and preset efficiency weights and temperature weights, and to allocate the total torque T2 of the drive motor to the front axle drive motor and the rear axle drive motor according to the optimal torque allocation coefficient y.

[0016] The present invention also provides a vehicle including the aforementioned control device.

[0017] The torque distribution control method for hybrid vehicles of the present invention introduces a temperature penalty factor mechanism. When the motor temperature approaches or exceeds the limit value, the torque distribution ratio is automatically adjusted to allocate more torque to the motor with a lower temperature. This optimizes the torque distribution strategy by combining the hybrid vehicle's operating mode and motor temperature changes, ensuring that the power system always operates in a state of optimal overall efficiency, reducing vehicle energy consumption, and effectively improving driving range. Attached Figure Description

[0018] Figure 1 This is a flowchart of the torque distribution control method for hybrid vehicles according to the present invention; Figure 2 This is a flowchart illustrating the method for determining the torque distribution coefficient between the front and rear axles. Figure 3 This is a flowchart of the method for determining the economic torque of an engine. Detailed Implementation

[0019] To facilitate understanding of the present invention, a more comprehensive description of the present invention will be given below with reference to the accompanying drawings, which illustrate several embodiments of the present invention. However, the present invention can be implemented in different forms and is not limited to the embodiments described in the text. Rather, these embodiments are provided to make the disclosure of the present invention more thorough and complete.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly associated with those skilled in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0021] The technical concept of this invention includes: Hybrid electric vehicles (HEVs), as a key technology bridging traditional gasoline vehicles and pure electric vehicles, possess significant advantages such as energy saving and emission reduction, range anxiety-free driving, and rapid power response. They can effectively adapt to the current complex and diverse driving scenarios and infrastructure conditions, resulting in a continuously increasing market penetration rate. The power system of a HEV typically integrates an engine, drive motor, power battery, and corresponding transmission mechanism, and can flexibly switch between various operating modes such as pure electric drive, series drive, and parallel drive according to driving conditions. The vehicle torque distribution strategy, as the core of the HEV energy management system, directly determines the output torque ratio and operating point selection of the engine and each drive motor, thus decisively affecting the vehicle's energy utilization efficiency, fuel economy, and driving range. Currently, the field of torque distribution technology for HEVs is showing a diversified development trend, with various optimization algorithms and control strategies emerging. Among them, torque distribution methods based on motor system efficiency optimization have been widely studied and applied due to their clear principles and good real-time performance. However, in practical applications, the aforementioned existing technologies still have obvious defects and shortcomings. On the one hand, most existing torque distribution methods based on motor system efficiency optimization are designed for pure electric vehicles, considering only the efficiency characteristics of one or more motors in pure electric drive mode. They do not specifically optimize for the complex operating conditions of hybrid electric vehicles, which involve multiple power source couplings and multiple operating modes. This makes it impossible to achieve efficient matching between the engine and motor, resulting in limited energy consumption optimization when directly applied to hybrid electric vehicles, severely restricting their application scope. On the other hand, existing technologies generally ignore the impact of motor temperature characteristics on the actual operating efficiency of the motor when calculating torque distribution. In fact, the copper losses, iron losses, and permanent magnet demagnetization characteristics of the motor are all closely related to temperature. Under low-temperature cold start or high-temperature continuous high-load operation conditions, the actual efficiency of the motor will deviate significantly from the efficiency MAP chart calibrated at room temperature. If the real-time changes in motor temperature are not considered, the torque distribution strategy based on a fixed efficiency model will cause the actual operating point of the power system to deviate from the optimal range. This not only fails to achieve the expected energy-saving effect but may also increase the overall vehicle energy consumption, shorten the driving range, and even cause reliability problems due to motor overheating. Therefore, how to combine the characteristics of various operating modes of hybrid electric vehicles, while fully considering the impact of motor temperature on system efficiency, and propose a torque distribution control method that can optimize the overall operating efficiency of the vehicle to further reduce energy consumption and increase driving range has become a pressing technical problem in this field. The technical solution of this invention is as follows: A method for torque distribution in a hybrid vehicle is provided, comprising: Based on the vehicle's required torque T and operating mode, determine whether the engine and drive motor provide torque; When both the engine and the drive motor provide torque, the portion of the vehicle's required torque T that exceeds the engine's economic torque T1 is allocated to the drive motor. That is, the engine's requested target torque is T1, and the total torque of the drive motor is determined to be T2 = T - T1. Based on the torque allocation coefficient y, the total torque T2 of the drive motor is allocated to the front axle drive motor and the rear axle drive motor. When the required torque T of the whole vehicle is less than the economic torque T1 of the engine, the target torque requested by the engine is determined to be T1, and the part of the economic torque T1 of the engine that exceeds the required torque T of the whole vehicle is allocated to the generator in combination with the state of charge of the power battery. When only the drive motor provides torque, the total torque T2 of the drive motor determines the vehicle's required torque T, and T2 is distributed to the front and rear axle drive motors according to the torque distribution coefficient y. The engine's economic torque T1 is determined through the following steps: Obtain the vehicle's operating mode; Obtain the state of charge of the vehicle's power battery; Obtain the vehicle's engine speed; Based on the above conditions, determine the engine's economic torque.

[0022] The front-to-rear axle distribution coefficient y of the total torque T2 of the drive motor is obtained through the following steps: Obtain the front axle drive motor current and voltage, front drive motor speed n1, torque t1, and real-time efficiency eff. front Real-time temperature front temp data; Obtain the rear axle drive motor current and voltage, rear drive motor speed n2, torque t2, and real-time efficiency eff. rear Real-time temperature temp data; Obtain the efficiency weight setting, temperature weight setting, wheel end speed N, and total drive motor torque T2; Based on the above conditions, determine the front and rear axle distribution coefficient y of the total torque T2 of the drive motor.

[0023] In practical implementation, the torque distribution control method described in this invention relies on the vehicle's existing sensor network and control unit. Multiple high-precision sensors are pre-installed on the vehicle, including but not limited to: a pedal position sensor for monitoring the accelerator pedal position, wheel speed sensors for monitoring wheel speed, an engine control unit (ECU) for monitoring real-time engine speed and torque, a motor controller (MCU) for monitoring the operating status of the drive motor and generator, a battery management system for monitoring the state of charge (SOC) of the power battery, and temperature sensors for monitoring the real-time temperature of the front and rear axle drive motors. These sensors collect data in real time at a millisecond-level sampling frequency and transmit the data to the vehicle control unit (VCU) via a controller area network (CAN) bus. The VCU, as the core control unit, embeds the torque distribution control algorithm of this invention. It analyzes, judges, and calculates the received real-time data, ultimately generating precise control commands, which are then sent to the engine control unit, motor controller, and battery management system for execution via the CAN bus. Specifically, in a first aspect, embodiments of the present invention provide a torque distribution control method for a hybrid vehicle, comprising the following steps: S1. Obtain the total required torque T for the entire vehicle and the current operating mode of the vehicle; S2. Based on the relationship between the total required torque T of the vehicle and the economic torque T1 of the engine, and combined with the state of charge of the power battery, allocate the target torque of the engine, the target torque of the generator and the total torque T2 of the drive motor. S3. Obtain the real-time operating parameters of the front axle drive motor and the rear axle drive motor. The real-time operating parameters shall include at least the real-time temperature and the real-time efficiency. S4. Based on the total torque T2 of the drive motor, real-time operating parameters, and preset efficiency and temperature weights, the optimal torque distribution coefficient y of the front and rear axle drive motors is calculated. S5. Based on the optimal torque distribution coefficient y, the total torque T2 of the drive motor is distributed to the front axle drive motor and the rear axle drive motor.

[0024] In this embodiment of the invention, by introducing a temperature weighting factor and combining the hybrid vehicle's operating mode and the drive motor torque distribution coefficient, a temperature rise penalty mechanism is established, a system efficiency optimization model is constructed, and the torque of the engine and drive motor is adjusted so that the engine and drive motor operate in the optimal economic point area, thereby reducing the vehicle's energy consumption and increasing the driving range.

[0025] This invention applies to a dual-motor four-wheel-drive hybrid vehicle with three operating modes: pure electric drive, series drive, and parallel drive. The vehicle's powertrain mainly consists of an engine, generator, front axle drive motor, rear axle drive motor, and power battery. The Vehicle Control Unit (VCU) serves as the core control unit, communicating with the Engine Control Unit (ECU), Motor Controller (MCU), Battery Management System (BMS), and various sensors via a Controller Area Network (CAN) bus. It collects vehicle operating status parameters in real time and executes the torque distribution control method described in this invention. The vehicle's current operating mode can include parallel mode, series mode, and pure electric mode.

[0026] The engine's output shaft is connected to the generator's rotor shaft via a clutch, and simultaneously coupled to the output shaft of the front axle drive motor via a transmission mechanism, ultimately connecting to the front axle differential. This allows the engine to directly drive the front wheels. The generator can function as either an electric motor, providing starting torque when the engine starts, or as a generator, converting excess mechanical energy into electrical energy during engine operation to charge the battery or directly power the drive motors. Both the front and rear axle drive motors are permanent magnet synchronous motors. The output shaft of the front axle drive motor is coupled to the engine's output shaft and connected to the front axle differential, while the output shaft of the rear axle drive motor is directly connected to the rear axle differential, enabling dual-motor four-wheel drive. The battery is electrically connected to the generator, front axle drive motor, and rear axle drive motor via a high-voltage distribution box, providing power to each motor and storing electrical energy generated by the generator and the regenerative braking system.

[0027] The vehicle controller communicates with the engine control unit (ECU), generator controller (GCU), motor controller, and battery management system (BMS) via a controller area network (CAN) bus. The vehicle controller collects real-time operating status parameters of each component, executes the torque distribution control algorithm described in this embodiment, generates corresponding control commands, and sends them to each execution unit to achieve unified and coordinated control of the powertrain system.

[0028] In addition, the vehicle is equipped with various sensors to collect vehicle operating status information, including: pedal position sensors to collect the driver's acceleration and braking intentions; wheel speed sensors, installed on the four wheels, to collect wheel speed signals; engine speed sensors to collect the real-time engine speed; motor speed sensors to collect the real-time speed of each motor; multiple temperature sensors to collect the real-time temperature of components such as the engine, generator, front axle drive motor, rear axle drive motor stator, and power battery; and current and voltage sensors, installed in the high-voltage distribution box and inside each motor controller, to collect the current and voltage signals of the high-voltage bus and each motor.

[0029] In this embodiment of the invention, when the vehicle is in parallel mode and the total required torque T of the vehicle is greater than the economic torque T1 of the engine, the target torque of the engine is T1, the target torque of the generator is 0, and the total torque of the drive motor is T2 = T - T1.

[0030] When the vehicle is in series mode, the total torque of the drive motor is T2=T, the target torque of the engine is T1, and the target torque of the generator is determined based on the economic torque of the engine T1 and the state of charge of the power battery.

[0031] When the vehicle is in pure electric mode, the engine target torque is 0, the generator target torque is 0, and the total torque of the drive motor is T2=T.

[0032] In this embodiment of the invention, the engine's economic torque T1 is determined through the following steps: Obtain fuel consumption rate data of the engine at different speeds; The engine speed range is traversed with a preset step size to determine the torque value with the lowest fuel consumption rate at each speed. A MAP of engine economic torque is generated based on the torque value with the lowest fuel consumption rate at each speed. Based on the current engine speed, the engine economic torque T1 is obtained by querying the engine economic torque MAP.

[0033] The calculation process for the optimal torque distribution coefficient y includes: Front axle torque distribution coefficient y front The variable is used to iterate within the range of 0 to 1 with a preset step size; For each front axle torque distribution coefficient y encountered during the iteration front Calculate the target torque T of the front axle motor. front and the target torque T of the rear axle motor rear T front =T2*y front T rear =T2*(1-y front ); Based on the target torque T of the front axle motor front Target torque T of the rear axle motor rear In addition to the real-time speeds of the front axle drive motor and the rear axle drive motor, the corresponding front axle motor efficiency (eff) is obtained by querying the motor efficiency MAP. front and rear axle motor efficiency rear ; Based on the real-time temperatures of the front axle drive motor and the rear axle drive motor, and the preset temperature limits, calculate the comprehensive temperature penalty factor temp. penalty ; Based on the front axle motor efficiency eff frontRear axle motor efficiency rear Comprehensive temperature penalty factor temp penalty Calculate candidate efficiency values ​​using preset efficiency weight η and preset temperature weight α. eff(y) ; Determine the candidate efficiency value. eff(y) The largest distribution coefficient is taken as the optimal torque distribution coefficient y.

[0034] In this embodiment of the invention, the comprehensive temperature penalty factor temp is used. penalty The calculation process includes: Calculate the front axle motor temperature penalty factor temp penaltyfront =max(0, (front temp -temp limit ) / 10), where front temp temp is the real-time temperature of the front axle drive motor. limit The preset temperature limit value; Calculate the temperature penalty factor temp for the rear axle motor penaltyrear =max(0, (rear temp -temp limit ) / 10), where rear temp This refers to the real-time temperature of the rear axle drive motor. Calculate the comprehensive temperature penalty factor temp penalty =α*(temp penaltyfront +temp penaltyrear ), where α is the preset temperature weight.

[0035] In this embodiment of the invention, the candidate efficiency value is... eff(y) The calculation formula is: candidate eff(y) =η*(T front +T rear ) / (T front / eff front +T rear / eff rear )-temp penalty Where η is the preset efficiency weight.

[0036] Figure 1 This is a flowchart illustrating a torque distribution method according to an exemplary embodiment. This method can be applied to hybrid vehicles, particularly plug-in or non-plug-in hybrid vehicles that support multiple operating modes such as pure electric, series, and parallel operation. When the vehicle is in Eco driving mode, the hybrid vehicle torque distribution control method described in this embodiment specifically includes the following steps: Step S1: Obtain the total torque requirement T of the vehicle and the current operating mode of the vehicle.

[0037] When the vehicle is in Eco mode, the vehicle controller first uses a sensor network to detect and analyze the driver's intentions in real time, obtaining parameters such as the total torque demand T and the rate of change of accelerator pedal opening. The total torque demand T is usually obtained by interpolating the accelerator pedal opening and the current vehicle speed using a preset driver torque demand map.

[0038] For example, the accelerator pedal opening signal is acquired via a pedal position sensor, while the vehicle controller acquires the wheel rotation speed signal via wheel speed sensors to obtain the vehicle speed. Based on the accelerator pedal opening value and vehicle speed, the vehicle controller queries a pre-calibrated driver demand torque MAP and calculates the total vehicle demand torque T using two-dimensional linear interpolation. The driver demand torque MAP is obtained through vehicle calibration tests; its horizontal axis represents vehicle speed, and its vertical axis represents accelerator pedal opening, with each coordinate point corresponding to a total vehicle demand torque value. This MAP fully considers the driver's power needs at different vehicle speeds and accelerator pedal openings, accurately reflecting the driver's driving intentions.

[0039] In addition, the vehicle controller also receives vehicle operating status parameters from the engine control unit, motor controller and battery management system via the CAN bus, including engine speed, engine coolant temperature, power battery state of charge (SOC) and the operating status of each motor, and combines these parameters to make a preliminary judgment on the vehicle's current possible operating mode.

[0040] Step S2: Based on the relationship between the total required torque T of the vehicle and the economic torque T1 of the engine, and in conjunction with the state of charge of the power battery, allocate the target torque of the engine, the target torque of the generator, and the total torque T2 of the drive motor.

[0041] The vehicle controller first obtains the engine's economic torque T1 under the current operating conditions. The engine's economic torque T1 refers to the torque value with the lowest fuel consumption rate at the current engine speed.

[0042] Then, the vehicle controller compares the total required torque T with the pre-calibrated engine economic torque T1. Based on the relationship between the total required torque T and the engine economic torque T1, and combined with the power battery SOC value compared with multiple preset thresholds, it determines the current operating mode the system should enter. Specifically: Parallel Mode Judgment and Execution: When the total demand torque T is greater than the engine's economic torque T1, and the battery SOC value is greater than the preset lower limit threshold for parallel operation (e.g., SOC > 30%, the lower limit threshold for parallel operation is preset to 30%), the vehicle controller determines that the vehicle has entered parallel mode. In this mode, the vehicle controller sends a command to the engine control unit, requesting the engine to output its economic torque T1, ensuring that the engine operates in the high-efficiency range with the lowest fuel consumption. At the same time, the vehicle controller calculates the torque that the drive motor needs to supplement, i.e., the total torque of the drive motor T2 = T - T1.

[0043] When the vehicle enters parallel mode, the vehicle controller sends a torque command to the engine control unit, controlling the engine to output a target torque of T1, thus keeping the engine operating in its most fuel-efficient range. At this time, the vehicle controller also sends a command to the generator controller, controlling the generator to output a target torque of 0, and the generator does not participate in energy conversion. This power distribution method fully utilizes the engine's high efficiency and the electric motor's rapid response to supplement power, meeting the driver's high power demands while maximizing fuel economy.

[0044] Series Mode Judgment and Execution: When the vehicle controller determines that the vehicle has entered series mode, it typically applies to two typical operating conditions: one is when the vehicle is traveling at low speed and requires high torque, in which case the direct drive efficiency of the engine is low; the other is when the battery SOC value is low, i.e., the power battery SOC < series start threshold, requiring engine assistance for charging. In series mode, the vehicle controller sets the total torque T2 of the drive motor to the total torque demand of the vehicle, i.e., T2 = T, and the vehicle is driven entirely by the drive motor. Simultaneously, the engine still starts and operates near the economic torque T1, but the engine does not directly drive the wheels; instead, it drives the generator to generate electricity. The generator torque is dynamically adjusted according to the engine's economic torque T1, the battery SOC state, and the vehicle's power demand. Part of the generated electricity is directly supplied to the drive motor, and the other part is used to charge the power battery.

[0045] Pure Electric Mode Judgment and Execution: When the vehicle controller determines that the vehicle is entering pure electric mode, i.e., the required torque T of the vehicle is relatively low (e.g., less than the lower limit of the engine's high-efficiency range) and the battery SOC value is sufficient, and the battery SOC value is greater than the preset lower limit threshold for pure electric mode (e.g., SOC > 50%, the lower limit threshold for pure electric mode is pre-calibrated to 50%), the system enters pure electric mode. In this mode, the engine torque is 0, and it is in a stopped or fuel-cut-off state. The vehicle controller sets the total torque T2 of the drive motor to the total required torque T of the vehicle, i.e., T2 = T. Pure electric mode is mainly suitable for starting, low-speed crawling, or constant-speed driving in congested urban traffic conditions. It can achieve zero emissions and low-noise operation, effectively reduce frequent engine start-stop and idling fuel consumption, and can significantly improve the fuel economy and ride comfort of the vehicle.

[0046] After determining the total torque T2 of the drive motors, regardless of whether the vehicle is in parallel mode or pure electric mode, as long as both motors are involved in the drive, the total torque T2 needs to be further rationally distributed to the front and rear axle drive motors to improve the overall efficiency of the electric drive system. This invention proposes a dynamic allocation method based on real-time temperature and efficiency MAP optimization.

[0047] Step S3: Obtain the real-time operating parameters of the front axle drive motor and the rear axle drive motor. The real-time operating parameters include at least the real-time temperature and the real-time efficiency.

[0048] After determining the total torque T2 of the drive motors, regardless of whether the vehicle is in parallel mode or pure electric mode, as long as both motors are involved in driving, the total torque T2 needs to be further distributed to the front axle drive motor and the rear axle drive motor. To achieve optimal torque distribution, the vehicle controller first needs to obtain the real-time operating parameters of the front and rear axle drive motors.

[0049] The vehicle controller sends data request commands to the front axle motor controller and the rear axle motor controller via the CAN bus. Upon receiving the commands, the front and rear axle motor controllers transmit the collected motor operating status parameters to the vehicle controller via the CAN bus. The real-time operating parameters of the front and rear axle drive motors specifically include: Real-time speed n1 of the front axle drive motor, real-time torque t1 of the front axle drive motor, and real-time temperature front of the front axle drive motor. temp Real-time efficiency of the front axle drive motor front The value is calculated by the front axle motor controller based on the motor speed, torque, and a pre-calibrated motor efficiency MAP. Real-time speed n2 of rear axle drive motor, real-time torque t2 of rear axle drive motor, real-time temperature rear of rear axle drive motor. temp Real-time efficiency of the rear axle drive motor rear The value is calculated by the rear axle motor controller based on the motor speed, torque, and a pre-calibrated motor efficiency MAP.

[0050] In addition, the vehicle controller also reads pre-stored system calibration parameters from its memory, including efficiency weight η, temperature weight α, and temperature limit temp. limit Efficiency weight η and temperature weight α are used to balance the importance of system efficiency and thermal load in the optimization objective. They are typically determined based on vehicle calibration tests. In this embodiment, the efficiency weight η is pre-calibrated to 0.7, and the temperature weight α is pre-calibrated to 0.3. Temperature limit temp limitis the highest temperature threshold at which the motor is allowed to operate stably for a long time. Exceeding this temperature will cause problems such as accelerated aging of the motor insulation and demagnetization of the permanent magnet, seriously affecting the service life and reliability of the motor. In this embodiment, the temperature limit temp limit is pre-calibrated to 120 °C.

[0051] Step S4: Based on the total torque T2 of the drive motor, the real-time operating parameters, and the preset efficiency weight and temperature weight, calculate the optimal torque distribution coefficient y of the front and rear axle drive motors.

[0052] The vehicle controller calculates the optimal torque distribution coefficient y of the front and rear axle drive motors by using the method of traversing and optimizing according to the obtained total torque T2 of the drive motor, the real-time operating parameters of the front and rear axle drive motors, and the system calibration parameters. Specifically, the calculation process of the optimal torque distribution coefficient y includes the following sub-steps: S41: Take the front axle torque distribution coefficient y front as a variable and traverse it within the range of 0 to 1 with a preset step size; Specifically, the front axle torque distribution coefficient y front represents the proportion of the torque borne by the front axle drive motor in the total torque T2 of the drive motor, and its value range is 0 to 1, y front = y.

[0053] When y = 0, all driving torques are borne by the rear axle drive motor; when y = 1, all driving torques are borne by the front axle drive motor; when 0 < y < 1, the driving torque is borne by the front and rear axle drive motors together.

[0054] In the embodiment of the present invention, to balance the calculation accuracy and the controller operation load, the traversing step size is preset to 0.05. Therefore, the possible values of y are 0, 0.05, 0.1, 0.15,..., 0.95, 1, a total of 21 value points.

[0055] S42: For each traversed front axle torque distribution coefficient y front , calculate the target torque T front of the front axle motor and the target torque T rear of the rear axle motor, T front = T2 * y front , T rear = T2 * (1 - y front ); S43: According to the target torque T front of the front axle motor, the target torque T rear of the rear axle motor, and the real-time speeds of the front axle drive motor and the rear axle drive motor, query the motor efficiency MAP diagram to obtain the corresponding front axle motor efficiency eff front and the rear axle motor efficiency eff rear; The motor efficiency MAP is obtained in advance through motor bench calibration tests. Its horizontal axis represents motor speed, and its vertical axis represents motor torque. Each coordinate point corresponds to a motor efficiency value. The motor efficiency MAP is stored in the vehicle controller's memory in the form of a two-dimensional array.

[0056] For the front axle drive motor, the vehicle controller calculates the target torque T of the front axle drive motor based on the real-time speed n1 of the front axle drive motor. front By querying the front axle motor efficiency MAP, the front axle motor efficiency eff can be obtained through two-dimensional linear interpolation. front .

[0057] Similarly, for the rear axle drive motor, the vehicle controller calculates the target torque T of the rear axle motor based on the real-time speed n2 of the rear axle drive motor. rear By querying the rear axle motor efficiency MAP, the rear axle motor efficiency eff is obtained through two-dimensional linear interpolation. rear .

[0058] S44: Calculate the comprehensive temperature penalty factor temp based on the real-time temperatures of the front axle drive motor and the rear axle drive motor, and the preset temperature limit values. penalty ; To fully consider the impact of motor temperature on system efficiency and reliability, and to prevent prolonged motor overheating, this invention introduces the concept of a temperature penalty factor. When the motor temperature approaches or exceeds the temperature limit, the temperature penalty factor increases, thereby reducing the candidate efficiency value corresponding to the allocation coefficient, allowing the system to automatically select a torque allocation scheme with lower thermal load. In this invention embodiment, the comprehensive temperature penalty factor temp... penalty The calculation process includes: Calculate the front axle motor temperature penalty factor temp penaltyfront =max(0, (front temp -temp limit ) / 10), where front temp temp is the real-time temperature of the front axle drive motor. limit This is a preset temperature limit value; the meaning of this formula is that only when the motor's real-time temperature is at a certain limit will the limit be applied. temp Exceeding the temperature limit (temp) limit The penalty factor is generated only when the temperature exceeds a certain threshold. The more the temperature exceeds a certain threshold, the larger the penalty value becomes. The step size is 1 for every 10°C exceeding the threshold.

[0059] Calculate the temperature penalty factor temp for the rear axle motor penaltyrear =max(0, (rear temp -temp limit ) / 10), where rear temp This refers to the real-time temperature of the rear axle drive motor. Calculate the comprehensive temperature penalty factor temp penalty =α*(temp penaltyfront +temp penaltyrear ), where α is the preset temperature weight. The larger this value is, the less ideal the current motor thermal load condition is, and the corresponding score will be deducted in the subsequent evaluation function.

[0060] The comprehensive temperature penalty factor is a weighted sum of the temperature penalty factors of the front and rear axle motors. The larger the temperature weight α, the greater the influence of temperature on the optimization objective.

[0061] S45: Based on the front axle motor efficiency eff front Rear axle motor efficiency rear Comprehensive temperature penalty factor temp penalty Calculate candidate efficiency values ​​using preset efficiency weight η and preset temperature weight α. eff(y) ; For the currently traversed allocation coefficient y, the system calculates T. front and T rear The efficiency maps of the front and rear axle motors, pre-calibrated and stored in the vehicle controller, are queried. Using a two-dimensional linear interpolation method, the efficiency point (eff) of the front axle motor at the current drive motor speed and torque is obtained. front and the efficiency point of the rear axle motor. rear .

[0062] To quantify the overall system efficiency under different allocation coefficients, this embodiment of the invention constructs a candidate efficiency evaluation function to calculate the candidate efficiency value. eff(y) Candidate efficiency value eff(y) Taking into account both system efficiency and heat load, a larger value indicates better overall system performance under that allocation coefficient. This function is based on the principle of electrical power conservation and will output mechanical power (T... front +T rear ) and input electrical power (T) front / eff front +T rear / eff rear The ratio of () to () is used as an evaluation index for system efficiency, and the comprehensive temperature penalty factor temp is subtracted. penalty Simultaneously, an efficiency weight η is introduced for overall scaling. Candidate efficiency value eff(y) The calculation formula is: candidate eff(y) =η*(T front +T rear ) / (T front / eff front +Trear / eff rear )-temp penalty Where η is the preset efficiency weight.

[0063] S46: Determine the candidate efficiency value. eff(y) The largest distribution coefficient is taken as the optimal torque distribution coefficient y; The vehicle controller iterates through all possible y-values ​​(from 0 to 1, with a step size of 0.05) and calculates the candidate corresponding to each y-value. eff(y) And use a comparison method to record the candidate eff(y) Find the maximum value of y. The y value corresponding to this maximum value is the optimal front axle torque distribution coefficient y under the current operating conditions. opt This means obtaining the optimal torque distribution coefficient between the front and rear axle drive motors. Finally, the vehicle controller will assign the optimal front axle torque distribution coefficient y... opt As control commands, they are sent to the front and rear axle motor controllers via the CAN bus to achieve real-time optimized torque distribution.

[0064] Step S5: Based on the optimal torque distribution coefficient, distribute the total torque T2 of the drive motor to the front axle drive motor and the rear axle drive motor; The vehicle controller uses the optimal torque distribution coefficient y between the front and rear axle drive motors. opt Calculate the final target torque T of the front axle motor. front_opt and the target torque T of the rear axle motor rear_opt : T front_opt = T2 × y opt T rear_opt = T2 × (1 - y opt ) Then, the vehicle controller sends the final target torque T for the front axle motor to the front axle motor controller via the CAN bus. front_opt Send the final target torque T of the rear axle motor to the rear axle motor controller. rear_opt After receiving the target torque command, the front axle motor controller and the rear axle motor controller precisely adjust the output torque of the motors so that the actual output torque of the motors tracks the target torque, ultimately achieving the optimal torque distribution between the front and rear axle drive motors.

[0065] The engine's economic torque T1 is a key benchmark value in the control strategy of this invention, and its accuracy directly affects the fuel economy of the entire vehicle. Figure 3 This is a flowchart illustrating the engine economic torque determination method according to an embodiment of the present invention. This method is typically completed during the engine bench calibration phase, and the results are stored in the vehicle controller in the form of a MAP (Map of Engines). Figure 3 As shown, the engine's economic torque T1 is determined through the following steps: First, in engine bench testing, the engine is controlled by a dynamometer to operate within a wide range of speeds and torques. Typically, engine speeds are traversed in 500 rpm increments, covering the entire range from idle to maximum speed; at each speed point, engine torque is traversed from minimum torque to maximum torque in increments of 10 Nm. During this process, a high-precision fuel consumption meter records the engine fuel consumption rate b (in g / kWh) at each operating point in real time.

[0066] Subsequently, the collected data was processed to record the fuel consumption rate *b* at different engine speeds and torques. Based on the vehicle's actual operating requirements, the torque point with the lowest fuel consumption rate at different engine speeds needs to be identified. That is, for each engine speed *n*... ICE_i Find the torque value T that minimizes b. ICE_i_min This torque value is the economic torque at that speed. These discrete (n) values... ICE_i T ICE_i_min Connecting these points forms the engine's optimal economic curve. In actual vehicle control, the vehicle controller can obtain the engine's economic torque T1 under the current operating conditions by querying this MAP or curve based on the current engine speed.

[0067] Secondly, embodiments of the present invention also provide a control device for executing the above-described torque distribution control method for hybrid vehicles. This control device is integrated into the vehicle controller or functions as an independent control unit, and mainly includes: The data acquisition module is used to acquire the total required torque T of the vehicle, the current working mode of the vehicle, the state of charge of the power battery, the economic torque T1 of the engine, and the real-time operating parameters of the front axle drive motor and the rear axle drive motor. The real-time operating parameters include at least real-time temperature and real-time efficiency. The first allocation module is used to allocate the target torque of the engine, the target torque of the generator and the total torque of the drive motor T2 according to the relationship between the total demand torque T of the vehicle and the economic torque T1 of the engine, combined with the state of charge of the power battery. The second allocation module is used to calculate the optimal torque allocation coefficient y of the front and rear axle drive motors based on the total torque T2 of the drive motor, real-time operating parameters, and preset efficiency and temperature weights, and to allocate the total torque T2 of the drive motor to the front and rear axle drive motors according to the optimal torque allocation coefficient y.

[0068] In this embodiment of the invention, the data acquisition module is used to collect vehicle operating status parameters via the CAN bus and acquire pre-stored system calibration parameters and MAP data. Specifically, the data acquisition module mainly includes: The driver intent acquisition unit is used to acquire accelerator pedal opening signals and brake pedal opening signals, etc. The engine status acquisition unit is used to collect parameters such as engine speed, engine coolant temperature, and engine torque. The motor status acquisition unit is used to collect parameters such as speed, torque, temperature, and efficiency of the front and rear axle drive motors and generators; The battery status acquisition unit is used to collect parameters such as voltage, current, SOC, and temperature of the power battery. The parameter storage unit is used to store the efficiency weight η, temperature weight α, and temperature limit temp. limit System calibration parameters such as threshold values ​​for each mode, as well as stored driver demand torque MAP, engine economic torque MAP, and front and rear axle motor efficiency MAP.

[0069] The data acquisition module filters, verifies, and normalizes the acquired raw signals to remove noise and interference, ensuring the accuracy and reliability of the data. It then converts the data into parameters usable by the algorithm, such as total torque demand T, battery SOC, motor temperature, and engine speed.

[0070] In this embodiment of the invention, the first allocation module is electrically connected to the data acquisition module and is used to determine the current working mode of the vehicle based on the total torque demand T of the vehicle, the economic torque T1 of the engine and the SOC of the power battery, and allocate the target torque of the engine, the target torque of the generator and the total torque T2 of the drive motor.

[0071] In this embodiment of the invention, the second allocation module is electrically connected to the first allocation module and the data acquisition module, and is used to calculate the optimal torque allocation coefficient y based on the total torque T2 of the drive motor, the real-time operating parameters of the front and rear axle drive motors, and the system calibration parameters. opt And according to y opt T2 is assigned to the front axle drive motor and the rear axle drive motor.

[0072] The first and second allocation modules are the core components of the device, consisting of a high-performance microprocessor and embedded software. These modules integrate the aforementioned torque distribution control algorithm. Based on parameters input from the sensor module, they first determine the operating mode and calculate the requested engine torque and the total drive motor torque T2. Subsequently, they initiate a motor torque distribution coefficient optimization algorithm, which, through iterative calculations and comparisons, determines the optimal distribution coefficient y. opt Finally, all calculation results are packaged to generate the final control commands.

[0073] The second distribution module generates control commands, such as target torque for the engine, generator, front axle motor, and rear axle motor, and sends them to the corresponding execution units via the CAN bus in a standardized message format. Upon receiving the commands, the engine control unit and motor controller precisely drive the actuators (such as fuel injectors and inverters) through internal current and speed closed-loop control, ultimately achieving accurate torque output.

[0074] Through the complete closed-loop control process achieved by the above modules, the technical solution of this invention can optimize the torque distribution of the engine and dual motors in real time and dynamically during actual vehicle operation, ensuring that the entire hybrid system always operates near the optimal economic operating point under the current conditions.

[0075] In summary, this invention, through the introduction of a temperature penalty factor based on real-time temperature and a motor torque distribution algorithm based on efficiency MAP optimization, combined with the accurate calculation of engine economic torque, constructs a comprehensive system efficiency optimization model. This solution effectively solves the problems of neglecting temperature characteristics and limited application scope in torque distribution in existing technologies, achieving significant technical effects of reducing overall vehicle energy consumption and increasing driving range.

[0076] Thirdly, embodiments of the present invention also provide a vehicle including a control device with the above-described structure. The vehicle is a hybrid vehicle, and since the vehicle of the present invention includes the control device and control method described in the above embodiments, it possesses all the advantages of the aforementioned control device and control method.

[0077] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A torque distribution control method for a hybrid vehicle, characterized in that, include: Obtain the total required torque T for the entire vehicle and the current operating mode of the vehicle; Based on the relationship between the total required torque T of the vehicle and the economic torque T1 of the engine, and combined with the state of charge of the power battery, the target torque of the engine, the target torque of the generator and the total torque T2 of the drive motor are allocated. The real-time operating parameters of the front axle drive motor and the rear axle drive motor are obtained, and the real-time operating parameters include at least real-time temperature and real-time efficiency. Based on the total torque T2 of the drive motor, the real-time operating parameters, and the preset efficiency weight and temperature weight, the optimal torque distribution coefficient of the front and rear axle drive motors is calculated. According to the optimal torque distribution coefficient, the total torque T2 of the drive motor is distributed to the front axle drive motor and the rear axle drive motor.

2. The torque distribution control method for hybrid vehicles according to claim 1, characterized in that, The calculation process for the optimal torque distribution coefficient includes: Front axle torque distribution coefficient y front The variable is used to iterate within the range of 0 to 1 with a preset step size; For each front axle torque distribution coefficient y encountered during the iteration front Calculate the target torque T of the front axle motor. front and the target torque T of the rear axle motor rear T front =T2*y front T rear =T2*(1-y front ); According to the target torque T of the front axle motor front Target torque T of the rear axle motor rear In addition to the real-time speeds of the front axle drive motor and the rear axle drive motor, the corresponding front axle motor efficiency (eff) is obtained by querying the motor efficiency MAP. front and rear axle motor efficiency rear ; Based on the real-time temperatures of the front axle drive motor and the rear axle drive motor, and the preset temperature limits, calculate the comprehensive temperature penalty factor temp. penalty ; According to the front axle motor efficiency eff front Rear axle motor efficiency rear Comprehensive temperature penalty factor temp penalty Calculate candidate efficiency values ​​using preset efficiency weight η and preset temperature weight α. eff(y) ; Determine the candidate efficiency value. eff(y) The largest distribution coefficient is taken as the optimal torque distribution coefficient y.

3. The torque distribution control method for hybrid vehicles according to claim 2, characterized in that, The comprehensive temperature penalty factor temp penalty The calculation process includes: Calculate the front axle motor temperature penalty factor temp penaltyfront =max(0, (front temp -temp limit ) / 10), where front temp temp is the real-time temperature of the front axle drive motor. limit The preset temperature limit value; Calculate the temperature penalty factor temp for the rear axle motor penaltyrear =max(0, (rear temp -temp limit ) / 10), where rear temp This refers to the real-time temperature of the rear axle drive motor. Calculate the comprehensive temperature penalty factor temp penalty =α*(temp penaltyfront +temp penaltyrear ), where α is the preset temperature weight.

4. The torque distribution control method for hybrid vehicles according to claim 3, characterized in that, The candidate efficiency value eff(y) The calculation formula is: candidate eff(y) =η*(T front +T rear ) / (T front / eff front +T rear / eff rear )-temp penalty Where η is the preset efficiency weight.

5. The torque distribution control method for hybrid vehicles according to any one of claims 1 to 3, characterized in that, When the vehicle is in parallel mode and the total required torque of the vehicle T is greater than the economic torque of the engine T1, the target torque of the engine is T1, the target torque of the generator is 0, and the total torque of the drive motor T2 = T - T1.

6. The torque distribution control method for hybrid vehicles according to any one of claims 1 to 3, characterized in that, When the vehicle is in series mode, the total torque of the drive motor is T2=T, the target torque of the engine is T1, and the target torque of the generator is determined based on the economic torque of the engine T1 and the state of charge of the power battery.

7. The torque distribution control method for hybrid vehicles according to any one of claims 1 to 3, characterized in that, When the vehicle is in pure electric mode, the target torque of the engine is 0, the target torque of the generator is 0, and the total torque of the drive motor is T2=T.

8. The torque distribution control method for hybrid vehicles according to any one of claims 1 to 3, characterized in that, The engine's economic torque T1 is determined through the following steps: Obtain fuel consumption rate data of the engine at different speeds; The engine speed range is traversed with a preset step size to determine the torque value with the lowest fuel consumption rate at each speed. Based on the torque value with the lowest fuel consumption rate at each speed, an engine economic torque MAP is generated. Based on the current engine speed, the engine's economic torque T1 is obtained by querying the engine's economic torque MAP.

9. A control device for implementing the torque distribution control method for a hybrid vehicle according to any one of claims 1 to 8, characterized in that, include: The data acquisition module is used to acquire the total required torque T of the vehicle, the current working mode of the vehicle, the state of charge of the power battery, the economic torque T1 of the engine, and the real-time operating parameters of the front axle drive motor and the rear axle drive motor. The real-time operating parameters include at least real-time temperature and real-time efficiency. The first allocation module is used to allocate the target torque of the engine, the target torque of the generator and the total torque of the drive motor T2 according to the relationship between the total demand torque T of the vehicle and the economic torque T1 of the engine, and in combination with the state of charge of the power battery. The second allocation module is used to calculate the optimal torque allocation coefficient y of the front and rear axle drive motors based on the total torque T2 of the drive motor, the real-time operating parameters, and preset efficiency weights and temperature weights, and to allocate the total torque T2 of the drive motor to the front axle drive motor and the rear axle drive motor according to the optimal torque allocation coefficient y.

10. A vehicle, characterized in that, Includes the control device as described in claim 9.

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