A method for energy management of range-extended electric vehicles

Abstract

This invention belongs to the field of hybrid electric vehicle technology, specifically providing a method for energy management of a range-extended electric vehicle, including the following steps: After the vehicle is powered on, the average speed and maximum speed over the nearest S kilometers are calculated in real time; when the average speed of the vehicle is higher than a first threshold and the maximum speed is higher than a second threshold, the vehicle enters normal operating mode; in normal operating mode, the engine output power benchmark is calculated using the vehicle's historical average power consumption array, and the engine output power is calculated by combining the engine output power SOC change compensation value, the engine output power PID compensation value, and the engine output power drive motor compensation value, thereby realizing that the engine output power adaptively follows the vehicle's power demand. It can predict the vehicle's current power demand. While ensuring the engine's response speed and operating stability, it improves the vehicle's energy utilization efficiency.

Description

Technical Field

[0001] This invention relates to the field of hybrid electric vehicle technology, and more specifically to a method for managing the energy of a range-extended electric vehicle. Background Technology

[0002] In recent years, global energy and environmental pollution pressures have intensified, prompting governments worldwide to formulate a series of new energy policies to promote the development of new energy vehicles. Among these, range-extended electric vehicles (REEVs) have gained widespread market acceptance due to their fuel economy and elimination of range anxiety. Compared to traditional hybrid vehicles, REEVs have a simpler structure, decoupling the range extender from the integrated transmission mechanism, allowing the engine to operate within a high-efficiency, low-emission range.

[0003] Range-extended electric vehicles (REEVs) have two energy sources: an engine and a battery. Properly allocating energy between these two sources is crucial for improving fuel economy and driving range. When the vehicle's power demand exceeds the engine's output, the battery discharges; when the vehicle's power demand is less than the engine's output, the battery charges to store excess charge. During operation, a good energy management strategy for REEVs needs to consider maintaining the engine in its high-efficiency range to reduce fuel consumption and ensure fuel economy; minimizing the number of battery charge / discharge cycles to reduce energy loss during charging and discharging, while extending battery life; and minimizing engine start-stop cycles to reduce energy and fuel loss during start-stop operations and extend the lifespan of engine start-stop components. Current REEV energy management strategies have the following problems:

[0004] 1. The engine uses a single operating mode in the control strategy, without setting a specific operating mode for specific operating conditions.

[0005] 2. The engine output power follows the instantaneous power of the vehicle's drive motor, resulting in frequent changes in the engine's operating conditions. This makes it impossible to guarantee that the engine is operating in its optimal operating range, thus increasing fuel consumption.

[0006] 3. The engine power follows the power battery's SOC and operates under fixed conditions. The engine output power cannot keep up with the vehicle's power demand, resulting in large fluctuations in the power battery's SOC. This increases the number of charge and discharge cycles of the power battery and the energy loss during the charging and discharging process.

[0007] 4. The calculation of the vehicle's required power is based on the current or historical power consumption of the vehicle's drive motors, ignoring the power consumption of auxiliary equipment in the vehicle, which leads to a large deviation in the calculation results.

[0008] 5. Frequent engine start-stop during vehicle operation wastes electrical energy and fuel, and reduces the lifespan of engine start-stop components.

[0009] 6. It requires load and slope sensors, the algorithm is relatively complex, the implementation cost is high, and it is not conducive to industrial promotion. Summary of the Invention

[0010] To address the problem that current management methods, where engine output power follows the instantaneous power of the vehicle's drive motor, lead to frequent changes in engine operating conditions and an inability to guarantee that the engine operates within its optimal range, thus increasing fuel consumption, this invention provides an effective and easy-to-implement energy management strategy for range-extended electric vehicles. This strategy utilizes a power adaptive mode under normal operating conditions and a power adaptive mode with low SOC compensation for the power battery, supplemented by engine output power SOC change compensation, engine output power PID compensation, and engine output power drive motor compensation. This achieves adaptive engine power following the vehicle's power demand.

[0011] The present invention provides a method for energy management of a range-extended electric vehicle, comprising the following steps:

[0012] After the vehicle is powered on, the average speed and maximum speed over the nearest S kilometers are calculated in real time.

[0013] When the average speed of the vehicle exceeds the first threshold and the maximum speed exceeds the second threshold, the vehicle enters normal operating mode.

[0014] In normal operating mode, the engine output power benchmark is calculated using the vehicle's historical average power consumption array. Combined with the engine output power SOC change compensation value, engine output power PID compensation value, and engine output power drive motor compensation value, the engine output power is calculated to achieve adaptive engine output power following the vehicle's power demand.

[0015] As a further limitation of the technical solution of the present invention, the engine output power benchmark is obtained by processing the average power consumption of the vehicle over multiple historical periods using a certain algorithm to obtain a predicted value of the vehicle's power demand at the current moment, and this predicted value is set as the engine output power benchmark. The calculation method of the engine output power benchmark includes:

[0016] The average power consumption of the vehicle over multiple historical periods is processed to obtain a predicted value of the vehicle's power demand at the current moment. This predicted value is then set as the benchmark for engine output power. The specific calculation method includes:

[0017] Calculate and store the average power consumption data of the whole vehicle for multiple historical periods, i.e., the average power consumption array of the whole vehicle vecAvgPw.

[0018] When the variance of the average power array of the whole vehicle energy consumption is less than or equal to the first limit, the algorithm of Engine_OutPw_Basic for engine output power is a weighted average algorithm.

[0019] Engine_OutPw_Basic =vecAvgPw(1)*W1+ vecAvgPw(2)*W2+…+ vecAvgPw(N)*W N Among them, W1~W N These are the weighting coefficients, and 1>W1>W2>…>W N >0, W1+W2+…W N-1 +W N =1.

[0020] Where vecAvgPw(1) is the average power consumption of the vehicle in the most recent cycle, and vecAvgPw(N) is the average power consumption of the vehicle in the furthest cycle.

[0021] When the variance of the vehicle energy consumption average power array is greater than the first limit, the average value of the vehicle energy consumption average power of the most recent i periods and the average value of the vehicle energy consumption average power of the adjacent long-term periods are subtracted; if the difference is greater than the first threshold, the weighted average value of the most recent vehicle energy consumption average power is used as the benchmark for engine output power.

[0022] Otherwise, calculate the average vehicle energy consumption power of the average vehicle energy consumption power of the i+p recent periods and the average vehicle energy consumption power of the adjacent long-term periods. If the difference is greater than the second threshold, the weighted average of the recent vehicle energy consumption power is used as the engine output power benchmark. This calculation is repeated multiple times. If the difference between the final average of the recent vehicle energy consumption power and the average of the adjacent long-term periods is less than the Mth threshold, the weighted average of the vehicle energy consumption power of all periods is used as the engine output power benchmark.

[0023] The average power consumption array for the entire vehicle is set to a length of f, defined in the near term as the period from the first cycle to the Mth cycle, and in the long term as the period from the (M+1)th cycle to the fth cycle. and , All are natural numbers;

[0024] The average power consumption of the vehicle in the most recent cycle is vecAvgPw(1), and the average power consumption of the vehicle in the furthest cycle is vecAvgPw(f). The calculation of the engine output power benchmark is expressed by the formula:

[0025] The recent average power consumption is AvgPwNear = vecAvgPw (1)

[0026] Long-term average energy consumption power AvgPwPast=vecAvgPw(2:4) / 3

[0027] If |AvgPwNear - AvgPwPast| ≥ C1, then Engine_OutPw_Basic = AvgPwNear

[0028] otherwise:

[0029] The recent average power consumption AvgPwNear = vecAvgPw(1:2) / 2

[0030] Long-term average energy consumption AvgPwPast = vecAvgPw(3:6) / 4

[0031] If |AvgPwNear - AvgPwPast| ≥ C2, then Engine_OutPw_Basic = AvgPwNear

[0032] otherwise:

[0033] The recent average power consumption AvgPwNear = vecAvgPw(1:3) / 3

[0034] Long-term average energy consumption power AvgPwPast = vecAvgPw(4:7) / 4

[0035] If |AvgPwNear - AvgPwPast| ≥ C3, then Engine_OutPw_Basic = AvgPwNear

[0036] otherwise:

[0037] …

[0038] The recent average power consumption AvgPwNear = [vecAvgPw(1) + ... vecAvgPw(e)] / e

[0039] Long-term average power consumption AvgPwPast = [vecAvgPw(e+1) + ... vecAvgPw(f)] / (fe)

[0040] If |AvgPwNear-AvgPwPast|≥C e Then the engine output power base is Engine_OutPw_Basic = AvgPwNear

[0041] otherwise:

[0042] Engine output power base Engine_OutPw_Basic=[vecAvgPw(1)+...vecAvgPw(f)] / f

[0043] Where: 0 < C1 < C2 … < C e <C e+1 …<C f and .

[0044] As a further limitation of the technical solution of the present invention, the method also includes:

[0045] When the vehicle is powered on, the stored average power consumption array of the vehicle is read and the current engine output power benchmark is calculated.

[0046] After power-on, the vehicle starts running. If the vehicle speed is greater than or equal to the speed threshold and the duration exceeds the time threshold, the average power consumption of the vehicle in a single cycle will be calculated. After each calculation cycle, the average power consumption array of the vehicle and the engine output power benchmark will be updated synchronously and a new calculation cycle will begin until the vehicle is powered off.

[0047] After the vehicle is powered off, the average power consumption array of the whole vehicle is written into the memory.

[0048] As a further limitation of the technical solution of the present invention, the method for calculating the average power consumption of the whole vehicle within a single cycle includes:

[0049] The average power consumption of the whole vehicle in a single cycle = the average power of the engine in a single calculation cycle - (the change in the remaining charge of the power battery in a single calculation cycle / cycle time).

[0050] As a further limitation of the technical solution of the present invention, the method also includes:

[0051] In normal operating mode, when the SOC of the power battery is greater than B1, the power battery has sufficient charge and the charging power is low. The engine stops and the vehicle operates in pure electric mode.

[0052] When the SOC of the power battery is greater than B2 but not greater than B1, the engine runs at idle speed to prevent the power battery charge from being too high and to maintain a certain kinetic energy recovery capability of the drive motor.

[0053] When the SOC of the power battery is greater than B3 but not greater than B2, the engine operates at its highest efficiency power.

[0054] When the SOC of the power battery is greater than B4 but not greater than B3, the battery charge is moderate, and the engine operates in power adaptive mode. In power adaptive mode, the engine's output power adaptively follows the power demand of the vehicle, and the SOC of the power battery fluctuates slightly around the target SOC. The engine's output power is set as the sum of the engine output power baseline, the engine output power SOC change compensation value, the engine output power PID compensation value, and the engine output power drive motor compensation value.

[0055] When the SOC of the power battery is less than or equal to B4, the engine operates in a low SOC compensation power adaptive mode. In this mode, while the engine's output power adaptively follows the vehicle's power demand, appropriate compensation power is added to accelerate the charging speed of the power battery while ensuring the engine's power generation efficiency, thereby raising the power battery's SOC to the target value. The engine output power is set as the sum of the engine output power baseline, the engine output power SOC change compensation value, the engine output power PID compensation value, the engine output power drive motor compensation value, and the engine output power low SOC compensation value.

[0056] As a further limitation of the technical solution of this invention, the engine output power SOC change compensation value is determined as follows: when the power battery SOC changes rapidly, it indicates a significant gap between the engine's output power and the current power demand of the vehicle. Therefore, the engine's output power needs to be corrected to reduce the rate of change of the power battery SOC, allowing the engine's output power to follow the vehicle's power demand. The calculation method for the engine output power SOC change compensation value includes:

[0057] Calculate the change in SOC of the power battery ΔSOC within the most recent set time in power adaptive mode and low SOC compensation mode.

[0058] When ΔSOC≥0, obtain the engine output power SOC change compensation value corresponding to the ΔSOC change when SOC rises;

[0059] The compensation value for changes in engine output power SOC is corrected based on the current SOC of the power battery and the current high-efficiency power range of the engine.

[0060] Output the corrected engine output power SOC change compensation value;

[0061] When ΔSOC < 0, obtain the engine output power SOC change compensation value corresponding to the decrease in SOC; execution steps: correct the engine output power SOC change compensation value based on the current SOC of the power battery and the current high-efficiency power range of the engine.

[0062] When ΔSOC ≥ 0, the compensation value is negative. When the SOC of the power battery is less than the target SOC, the lower the SOC of the power battery, the greater the compensation value. When the SOC of the power battery is greater than the target SOC, the higher the SOC of the battery, the smaller the compensation value. When ΔSOC < 0, the compensation value is positive. When the SOC of the power battery is less than the target SOC, the lower the SOC of the power battery, the greater the compensation value. When the SOC of the power battery is greater than the target SOC, the higher the SOC of the power battery, the smaller the compensation value.

[0063] The engine output power low SOC compensation value is a positive compensation value added to the engine's set power when the power battery SOC is low. The lower the SOC, the larger the compensation value.

[0064] As a further limitation of the technical solution of the present invention, the method for calculating the compensation value of the engine output power drive motor includes:

[0065] The input power reference of the drive motor is obtained by subtracting the power of the auxiliary components from the output power reference of the engine.

[0066] Subtract the drive motor's input power reference from the real-time input power of the drive motor to obtain the real-time difference in engine output power based on the drive motor's input power.

[0067] The real-time difference in engine output power is corrected to obtain the compensation value for the engine output power drive motor.

[0068] As a further limitation of the technical solution of the present invention, the engine output power PID compensation value is to set a target SOC of the power battery, and then calculate the difference between the current SOC of the power battery and the target SOC through the PID algorithm, and then add a PID compensation value based on the target SOC of the power battery to the engine output power.

[0069] The calculation method for the PID compensation value of engine output power includes:

[0070] Obtain the current SOC and target SOC of the power battery;

[0071] The difference between the current SOC and the target SOC of the power battery is used to calculate the PID compensation value of the engine output power through a PID algorithm.

[0072] The PID compensation value of the engine output power is corrected based on the current SOC of the power battery and the current high-efficiency power range of the engine, and the output engine output power is based on the PID compensation value of the target SOC.

[0073] The PID compensation value for engine output power is the output value obtained by inputting the target SOC and the current SOC of the power battery into the PID calculator. When switching between power adaptive mode, low SOC compensation power adaptive mode, and other modes, the output value of the PID module is reset to 0.

[0074] As a further limitation of the technical solution of the present invention, the calculation method for the high-efficiency power range of the engine includes:

[0075] Based on the current operating environment and the operating status of the engine and power battery, obtain the engine power generation efficiency Map and the power battery charge and discharge efficiency Map under different SOCs.

[0076] The power generation efficiency Map of the vehicle is obtained by multiplying the engine power generation efficiency Map with the charge and discharge efficiency Map of the power battery under different SOCs.

[0077] By combining the engine output power benchmark, the high-efficiency power range of the engine is obtained by generating the maximum and minimum operating power of the engine.

[0078] Within this high-efficiency power range, the engine can quickly respond to the vehicle's power demands while also ensuring the vehicle's power generation efficiency.

[0079] As a further limitation of the technical solution of the present invention, the method also includes:

[0080] When the average speed of the vehicle is lower than the first threshold and the maximum speed is lower than the second threshold, the vehicle operates in low-speed mode.

[0081] In low-speed operating mode, the engine output power is set according to the SOC of the power battery;

[0082] When the vehicle is running in normal operating mode, if the parking time is detected to be greater than the set time threshold and the power battery charge is not greater than the charging threshold within a single vehicle energy consumption average power calculation cycle, the vehicle enters parking charging mode.

[0083] In parking charging mode, the engine is set to run at its highest efficiency power; the parking time is the continuous time during which the vehicle speed is below the vehicle speed threshold.

[0084] When the vehicle is running in normal operating mode, if the engine or power battery reports a level 2 fault, the vehicle will run in level 2 fault mode.

[0085] In Level 2 fault mode, the engine is set to operate at its highest efficiency power.

[0086] It enables the differentiation and identification of the vehicle's operating conditions, allowing for the implementation of specific operating modes for different conditions. Under all operating conditions, it improves the vehicle's power generation efficiency, enhances the vehicle's operating economy, reduces pollutant emissions, achieves efficient and stable engine operation, reduces the number of charge and discharge cycles of the power battery, and extends the lifespan of engine start-stop components and the power battery.

[0087] In all vehicle operating modes, if the SOC of the power battery is low, the output power of the engine will be limited to reduce the charging speed of the power battery and extend its life. At the same time, the rate of change of engine power also needs to be limited to further improve the stability of engine operating conditions.

[0088] When the vehicle is running in pure electric mode, the engine remains off, and the power battery provides all the energy for the vehicle's operation.

[0089] When the SOC of the power battery drops to a certain level and the power battery reports a power limit fault, if the vehicle does not report a low fuel level fault, the engine will start and operate at its highest efficiency power to prevent the power battery from running out of power and to maintain vehicle operation. When the SOC of the power battery recovers to a certain level, the engine will be shut off.

[0090] As can be seen from the above technical solutions, the present invention has the following advantages:

[0091] This strategy categorizes the vehicle's operating modes into low-speed operating modes such as those at ports, normal operating modes, parking and charging modes, and secondary fault modes for the engine and power battery, thus enabling operating condition identification and allowing the vehicle to operate in a specific mode under different operating conditions.

[0092] In low-speed operating conditions such as those at ports, the vehicle's energy consumption is low. Using the battery's State of Charge (SOC) as a single condition, the engine operates at a fixed power output at different SOCs, ensuring stable low-power, high-efficiency engine operation. In parking charging mode, power generation efficiency is improved while reducing engine noise, enhancing passenger comfort. In engine and battery level-two fault modes, vehicle operating time is maximized, minimizing the possibility of breakdowns. In both normal operating conditions and low battery SOC compensation modes, the average historical energy consumption power of the vehicle over multiple cycles is calculated. Using the engine output power benchmark algorithm in this strategy, the current power demand of the vehicle can be predicted. Supplemented by engine output power SOC change compensation, engine output power PID compensation, and engine output power drive motor compensation, the engine power adaptively follows the vehicle's power demand. Based on the vehicle's power generation efficiency, the engine's high-efficiency power range is obtained. Using this high-efficiency power range, the above compensation values ​​and the final engine output are corrected, improving the vehicle's energy utilization efficiency while ensuring engine response speed and operational stability.

[0093] During vehicle operation, the engine can operate almost continuously, significantly reducing energy waste from frequent engine start-stop cycles. In different operating modes, the engine operates within its high-efficiency power range, improving overall vehicle energy utilization efficiency while reducing harmful gas emissions. The engine's operating power and the battery's state of charge (SOC) fluctuate minimally, reducing the number of battery charge-discharge cycles and extending the lifespan of the engine start-stop components.

[0094] This method eliminates the need for vehicle-mounted load sensors, slope sensors, cloud-based GPS, and other equipment, resulting in low implementation costs. The algorithm is simple, reliable, and effective, and can perform real-time offline calculations, making it easy to promote and possessing high commercial value.

[0095] Furthermore, the design principle of this invention is reliable, the structure is simple, and it has a very wide range of application prospects.

[0096] Therefore, it is evident that the present invention has outstanding substantive features and significant progress compared with the prior art, and the beneficial effects of its implementation are also obvious. Attached Figure Description

[0097] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0098] Figure 1 This is a schematic diagram of the energy flow of a range-extended electric vehicle provided in an embodiment of the present invention.

[0099] Figure 2 This is a schematic diagram of the engine output power benchmark calculation process provided in an embodiment of the present invention.

[0100] Figure 3 This is a schematic diagram of the engine output power benchmark calculation algorithm provided in an embodiment of the present invention.

[0101] Figure 4 This is a schematic diagram of the calculation process for the engine output power SOC change compensation value provided in an embodiment of the present invention.

[0102] Figure 5 This is a schematic diagram of the calculation process for the PID compensation value of engine output power provided in an embodiment of the present invention.

[0103] Figure 6 This is a schematic diagram of the calculation process for the compensation value of the engine output power drive motor provided in an embodiment of the present invention.

[0104] Figure 7 This is a schematic diagram of the calculation process for the high-efficiency power range of an engine provided in an embodiment of the present invention.

[0105] Figure 8 This is a schematic diagram of the calculation process for low SOC compensation value of engine output power provided in an embodiment of the present invention.

[0106] Figure 9 This is a diagram illustrating actual vehicle operation data provided by the method in this embodiment of the invention. Detailed Implementation

[0107] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0108] Figure 1 This is a schematic diagram of the energy flow in a range-extended electric vehicle (REEV). In a REEV, the electricity generated by the engine can be directly supplied to the vehicle's drive motor and auxiliary machinery. Excess electricity generated by the engine can also directly charge the battery. In pure electric mode or when the engine's power generation is lower than the vehicle's power consumption, the battery provides power to the drive motor and auxiliary machinery. During braking and coasting, the energy recovered by the drive motor is fed back into the battery. Specifically, the motor's recoverable power is ≤ (maximum rechargeable power of the battery - engine's power generation).

[0109] After the vehicle is powered on, it enters either pure electric mode or hybrid mode depending on the status of the hybrid switch. In pure electric mode, the engine stops, and the battery provides all the energy for the vehicle's operation. When the battery charge drops below 20% and the vehicle does not report a low fuel level fault, the engine automatically starts to operate at its highest efficiency power to prevent the battery from running out of power and affecting the vehicle's operation and battery life.

[0110] After the vehicle is powered on, the average speed and maximum speed over the nearest S kilometers are calculated and determined in real time. It is then checked whether the average speed is less than V1 and the maximum speed is less than V2. If so, the vehicle enters a low-speed operating mode. In this mode, the engine's operating power is determined by the battery charge; when the battery charge is high, the engine operates at lower power, and when the battery charge is low, the engine operates at higher power. If not, the vehicle enters a normal operating mode. In this mode, the engine output power benchmark is calculated using the vehicle's historical average power consumption array. This benchmark is then combined with compensation values ​​for engine output power SOC changes, engine output power PID compensation values, and engine output power drive motor compensation values ​​to calculate the engine's output power, enabling the engine output power to adaptively follow the vehicle's power demand.

[0111] When calculating the average vehicle speed, data with a speed of ≤2km / h are excluded.

[0112] In low-speed operating conditions such as at ports, the engine's operating power is determined solely by the state of charge (SOC) of the power battery. When the SOC of the power battery is low, the engine operates at higher power; when the SOC of the power battery is high, the engine operates at lower power.

[0113] The normal operating modes are divided into pure electric mode, idle mode, highest efficiency power operation mode, power adaptive mode and power adaptive mode with low SOC compensation of the power battery, based on the power battery SOC range.

[0114] For example, the power battery SOC-engine output power map is shown in Table 1:

[0115] Table 1

[0116] Power battery SOC / % 0 15 20 40 60 80 85 90 100 Engine output power / kW / h 20 20 45 40 30 25 20 0 0

[0117] When the vehicle's average speed and maximum speed exceed a certain limit, the vehicle will enter normal operating mode. Normal operating mode is further divided into pure electric operation mode, idle operation mode, maximum efficiency power operation mode, power adaptive mode, and power adaptive mode with low battery SOC compensation, depending on the state of charge (SOC) of the power battery.

[0118] For example, the relationship between the power battery SOC and the mode, and the engine output power are shown in Table 2 below:

[0119] Table 2

[0120]

[0121] When the vehicle is running, if the vehicle speed is less than 2 km / h for more than 2 minutes, and the current SOC of the power battery is less than 80%, the vehicle enters the parking charging mode. In this mode, the engine operates at its highest efficiency power.

[0122] When a level 2 fault is detected in the engine or power battery while the vehicle is running, the engine will still operate at its highest efficiency power.

[0123] Figure 2 This document details the calculation process for the engine output power benchmark in this embodiment. The average real-time engine output power within a single calculation cycle is subtracted from (change in remaining battery charge during this calculation cycle / cycle time) at the end of the cycle to obtain the average vehicle energy consumption power within that cycle. In this embodiment, the engine output power benchmark is calculated using the average vehicle energy consumption power over the most recent 10 calculation cycles.

[0124] When the vehicle is powered on, the historical energy consumption array vecAvgPw (length 10) stored in memory is first read, and the current engine output power benchmark is calculated. After power-on, the vehicle starts running. If the vehicle speed is ≥2km / h and lasts for more than 2 seconds, the average power consumption of the vehicle within a single cycle is calculated. After each calculation cycle, the historical energy consumption array and the engine output power benchmark are updated synchronously, and a new calculation cycle begins until the vehicle is powered off. After the vehicle is powered off, the historical energy consumption array is written back to memory.

[0125] Within a single vehicle energy consumption average power calculation cycle, if the vehicle speed is <2km / h and the duration is ≥2min, the current calculation cycle is paused, and updates to the historical energy consumption array and engine output power benchmark are suspended. Simultaneously, the vehicle enters parking charging mode, and the engine operates at maximum efficiency power. The calculation for this cycle resumes only when the vehicle speed is ≥2km / h and remains at that speed for more than 2 seconds.

[0126] Figure 3 This is a schematic diagram of the engine output power benchmark calculation algorithm in this embodiment. When the variance of the historical energy consumption average power array vecAvgPw is ≤50, the algorithm for the engine output power benchmark is a weighted average algorithm. This algorithm is suitable for scenarios where the vehicle's operating conditions do not change significantly.

[0127] For example, Engine_OutPw_Basic =

[0128] vecAvgPw(1)*0.24+vecAvgPw(2)*0.18+vecAvgPw(3)*0.15+vecAvgPw(4)*0.12 +vecAvgPw(5)*0.1+vecAvgPw(6)*0.08+vecAvgPw(7)*0.06+vecAvgPw(8)*0.04+ vecAvgPw(9)*0.02+vecAvgPw(10)*0.01.

[0129] Where vecAvgPw(1) is the average power consumption of the vehicle in the most recent cycle, and vecAvgPw(10) is the average power consumption of the vehicle in the furthest cycle.

[0130] When the variance of the historical average energy consumption power array vecAvgPw is greater than 50, the engine output power benchmark calculation method is as follows: The average vehicle energy consumption power of one or more recent periods is subtracted from the average vehicle energy consumption power of several adjacent periods. If the difference is large, the weighted average of the recent vehicle energy consumption power is used as the engine output power benchmark. Otherwise, the difference between the average vehicle energy consumption power of more recent periods and the average vehicle energy consumption power of several adjacent periods is calculated. If the difference is large, the weighted average of the recent vehicle energy consumption power is used as the engine output power benchmark. This calculation is repeated multiple times. If the final difference between the average recent vehicle energy consumption power and the average vehicle energy consumption power of several adjacent periods is small, the weighted average of the average vehicle energy consumption power of all periods is used as the engine output power benchmark.

[0131] For example, Table 3 shows the correspondence between the recent average vehicle energy consumption power and the long-term average vehicle energy consumption power. As shown in Table 3, firstly, the recent average vehicle energy consumption power and the long-term average vehicle energy consumption power are calculated according to the formula in Condition 1, and the difference between the two is calculated. If the absolute value of the difference is greater than or equal to the comparison value, then the engine output power benchmark = the recent average vehicle energy consumption power calculated in Condition 1. If the absolute value of the difference is less than the comparison value, then it is calculated and compared again according to Condition 2, until Condition 7 is compared. Finally, if the absolute value of the difference between the recent average vehicle energy consumption power and the long-term average vehicle energy consumption power in Condition 7 is less than the comparison value in Condition 7, then the engine output power benchmark = vecAvgPw(1:10) / 10.

[0132] Table 3

[0133] condition Recent average power consumption of the whole vehicle Long-term average power consumption of the whole vehicle Comparison value 1 vecAvgPw(1) / 1 vecAvgPw(2:4) / 3 Maximum power in the engine's high-efficiency power range: 1.85 2 vecAvgPw(1:2) / 2 vecAvgPw(3:6) / 4 Engine high-efficiency power range maximum power / 4 3 vecAvgPw(1:3) / 3 vecAvgPw(4:7) / 4 Engine's highest power output in its efficient power range / 6.5 4 vecAvgPw(1:4) / 4 vecAvgPw(5:8) / 4 Maximum power output in the engine's high-efficiency power range: 9.6 5 vecAvgPw(1:5) / 5 vecAvgPw(6:10) / 5 Maximum power in the engine's high-efficiency power range: 13.3 6 vecAvgPw(1:6) / 6 vecAvgPw(7:10) / 4 Engine high-efficiency power range maximum power / 18 7 vecAvgPw(1:7) / 7 vecAvgPw(8:10) / 3 Engine high-efficiency power range maximum power / 24

[0134] When the SOC of the power battery changes too quickly, it indicates that the operating conditions of the vehicle have changed significantly, and the output power of the engine needs to be corrected so that the engine output power can keep up with the power demand of the vehicle. Figure 4This is a schematic diagram illustrating the calculation process for the engine output power SOC change compensation value. The calculation calculates the recent SOC change value ΔSOC of the power battery in power adaptive mode and low SOC compensation mode. When ΔSOC ≥ 0, the compensation value for engine output power SOC change corresponding to ΔSOC when SOC increases is looked up from a table. In this case, the compensation value is negative, and when the power battery SOC is less than the target SOC, the lower the power battery SOC, the larger the compensation value; when the power battery SOC is greater than the target SOC, the higher the battery SOC, the smaller the compensation value. When ΔSOC < 0, the compensation value for engine output power SOC change corresponding to ΔSOC when SOC decreases is looked up from a table. In this case, the compensation value is positive, and when the power battery SOC is less than the target SOC, the lower the power battery SOC, the larger the compensation value; when the power battery SOC is greater than the target SOC, the higher the power battery SOC, the smaller the compensation value.

[0135] Figure 5 This is the calculation process for the PID compensation value of engine output power. In this embodiment, the target SOC of the power battery is set to 75%. After inputting the current SOC of the power battery into the PID calculator, the PID calculation value can be obtained. When switching between the power adaptive mode and the low SOC compensation power adaptive mode and other modes, the output value of the PID module is reset to 0. When the difference between the SOC of the power battery and the target SOC is large, the upper and lower limits of the PID calculation value are appropriately increased; similarly, when the difference between the SOC of the power battery and the target SOC is small, the upper and lower limits of the PID calculation value are appropriately decreased. At the same time, when the maximum power of the engine's high-efficiency power range is large, the upper and lower limits of the PID calculation value are appropriately increased; similarly, when the maximum power of the engine's high-efficiency power range is small, the upper and lower limits of the PID calculation value are appropriately decreased. The corrected PID calculation value is the PID compensation value for engine output power. Through correction, the stability of engine operating conditions is ensured while preserving the engine response speed to the maximum extent.

[0136] When the vehicle is running in normal operating mode, if a level 2 fault is detected in the engine or power battery, the vehicle will run in level 2 fault mode. In this mode, the engine will run at its highest efficiency power to extend the running time of the engine and power battery as much as possible and avoid the vehicle breaking down on the road.

[0137] During vehicle operation, the drive motor is the most significant energy-consuming component. To ensure the engine's output power follows the vehicle's energy consumption, the power variation of the drive motor must be considered. In this embodiment, the input power reference of the drive motor is approximated by subtracting the auxiliary power Acc_OutPw_Current from the engine's output power reference Engine_OutPw_Basic (the predicted power demand of the vehicle at the current moment). Subtracting the drive motor's input power reference from the real-time input power of the drive motor yields the real-time difference in engine output power based on the drive motor's input power. Correcting this real-time difference using a lookup table yields the engine output power drive motor compensation value Engine_Pw_Motor_Cmpst. Figure 6 A schematic diagram illustrating the calculation process for the compensation value of the motor driven by the engine output power.

[0138] Engine power generation efficiency is a key parameter affecting overall vehicle energy consumption. The overall vehicle power generation efficiency depends on both the engine's power generation efficiency and the charging / discharging efficiency of the battery. By calculating the overall vehicle power generation efficiency, the engine's high-efficiency power range can be obtained. The general calculation process is as follows: Figure 7 As shown. Based on the current operating environment and the operating status of the engine and power battery, the engine power generation efficiency Map and the power battery charge / discharge efficiency Map under different SOCs are obtained. Multiplying the engine power generation efficiency Map and the power battery charge / discharge efficiency Map under different SOCs yields the vehicle's power generation efficiency Map. Combining the engine output power baseline Engine_OutPw_Basic with the vehicle's power generation efficiency Map yields the engine's high-efficiency power range. Within this high-efficiency power range, it is ensured that the engine can quickly respond to the vehicle's power demands while maintaining the vehicle's power generation efficiency.

[0139] When the battery charge is low, a positive compensation value needs to be added to the engine output power to accelerate the battery charging speed. A schematic diagram of the calculation process for the low SOC compensation value of engine output power is shown below. Figure 8 As shown in Table 4, for example, the low SOC compensation values ​​for engine output power are:

[0140] Table 4

[0141] Power battery SOC / % 0 20 25 30 40 50 60 65 80 100 Low SOC compensation value (maximum value in the high-efficiency power range) 0 0.04 0.16 0.16 0.12 0.08 0.04 0.02 0 0

[0142] In power adaptive mode and low SOC compensation power adaptive mode, the final output engine operating power is corrected by the engine's high-efficiency power range.

[0143] In all operating modes, when the SOC of the power battery is at a low level, the output power of the engine is limited, the charging speed of the power battery is reduced, and the life of the power battery is extended.

[0144] In all the above modes, the engine's variable power speed is limited to further improve the stability of the engine's operating conditions.

[0145] Real-world driving data of a vehicle equipped with this range-extended electric vehicle energy management strategy is as follows: Figure 9 As shown. From top to bottom, the curves represent: Vehicle Speed, Battery SOC (Bat_SOC), Average Vehicle Energy Consumption Power (vecAvgPwResult01) for the latest calculation cycle, Real-time Engine Output Power (Engine_ActualPw), Engine Output Power Baseline (Engine_OutPw_Basic), Engine Output Power PID Compensation Value (Engine_Pw_SOC_PID_Cmpst), Engine Output Power SOC Change Compensation Value (Engine_Pw_SOC_ChgCmpst), Engine Output Power Drive Motor Compensation Value (Engine_Pw_MotorPw_Cmpst), Engine Output Power Low SOC Compensation Value (Engine_Pw_LowSOC_Cmpst), and Vehicle Operating Mode (VCU_Engine_Pw_Mode).

[0146] At the start of the trip, the initial SOC of the power battery was 56.5%, the engine operating mode (VCU_Engine_Pw_Mode) was 7, and the vehicle operating mode was low SOC compensation power adaptive mode. Around 41 minutes, the power battery SOC rose to 70%, the vehicle operating mode switched to power adaptive mode, and the engine operating mode (VCU_Engine_Pw_Mode) value was 6. At 63 minutes, the power battery SOC reached the target value of 75%. From 63 minutes to 113 minutes, the power battery SOC fluctuated slightly around 75%, indicating that the engine's output power could follow the vehicle's power demand in real time, and the number of charge / discharge cycles of the power battery remained at a low level. At 113 minutes, the driver stopped for a rest. At 115 minutes, the vehicle's parking time exceeded 2 minutes, the engine operating mode (VCU_Engine_Pw_Mode) value changed to 3, the vehicle switched to parking charging mode, and the engine output power (FC_ActualPw) was set to the highest efficiency power. At 117 minutes, the driver finished resting, and the vehicle continued driving. At this point, the SOC of the power battery is 77%, and the engine operating mode VCU_Engine_Pw_Mode value changes back to 6, with the vehicle operating in power adaptive mode. After 121 minutes, the driver turns on the pure electric switch, the engine operating mode VCU_Engine_Pw_Mode value changes to 1, and the vehicle operates in pure electric mode until the end of the trip.

[0147] As can be seen from the engine's real-time output power curve, the engine's output power curve is smooth during operation, the engine's operating conditions are stable, and it operates within the engine's high-efficiency power range. This demonstrates that the energy management strategy of this range-extended electric vehicle is highly effective, reducing overall fuel consumption, improving overall vehicle operating economy, and extending the lifespan of the engine and power battery.

[0148] The range-extended electric vehicle energy management method of the present invention, comprising the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein, can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of each example have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of the present invention.

[0149] Although the present invention has been described in detail with reference to the accompanying drawings and preferred embodiments, the invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the invention should also be covered within the protection scope of the invention. Therefore, the protection scope of the invention should be determined by the scope of the claims.

Claims

1. A method for energy management of a range-extended electric vehicle, characterized in that, Includes the following steps: After the vehicle is powered on, the average speed and maximum speed over the nearest S kilometers are calculated in real time. Determine if the average vehicle speed is less than V1 and the maximum vehicle speed is less than V2. If yes, the vehicle enters low-speed operating mode; otherwise, the vehicle enters normal operating mode. Under normal operating conditions, when the SOC of the power battery is greater than B1, the engine stops and the vehicle operates in pure electric mode. When the SOC of the power battery is greater than B2 but not greater than B1, the engine runs at idle speed. When the SOC of the power battery is greater than B3 but not greater than B2, the engine operates at its highest efficiency power. When the SOC of the power battery is greater than B4 but not greater than B3, the engine operates in power adaptive mode. In power adaptive mode, the engine output power is set as the sum of the engine output power reference, the engine output power SOC change compensation value, the engine output power PID compensation value, and the engine output power drive motor compensation value. When the SOC of the power battery is less than or equal to B4, the engine operates in a low SOC compensation power adaptive mode. In the low SOC compensation power adaptive mode, the engine output power is set as the sum of the engine output power reference, the engine output power SOC change compensation value, the engine output power PID compensation value, the engine output power drive motor compensation value, and the engine output power low SOC compensation value.

2. The energy management method for a range-extended electric vehicle according to claim 1, characterized in that, The calculation methods for engine output power benchmarks include: The average power consumption of the vehicle over multiple historical periods is processed to obtain a predicted value of the vehicle's power demand at the current moment. This predicted value is then set as the benchmark for engine output power. The specific calculation method includes: Calculate and store the average power consumption data of the whole vehicle for multiple historical periods, i.e., the average power consumption array of the whole vehicle. When the variance of the average power array of the whole vehicle energy consumption is less than or equal to the first limit, the algorithm for the engine output power benchmark adopts the weighted average algorithm. When the variance of the vehicle energy consumption average power array is greater than the first limit, the average value of the vehicle energy consumption average power of the most recent i periods and the average value of the vehicle energy consumption average power of the adjacent long-term periods are subtracted; if the difference is greater than the first threshold, the weighted average value of the most recent vehicle energy consumption average power is used as the benchmark for engine output power. Otherwise, calculate the average vehicle energy consumption power of the average vehicle energy consumption power of the i+p recent periods and the average vehicle energy consumption power of the adjacent long-term periods. If the difference is greater than the second threshold, the weighted average of the recent vehicle energy consumption power is used as the engine output power benchmark. This calculation is repeated multiple times. If the difference between the final average of the recent vehicle energy consumption power and the average of the adjacent long-term periods is less than the Mth threshold, the weighted average of the vehicle energy consumption power of all periods is used as the engine output power benchmark. The average power consumption array for the entire vehicle is set to a length of f, defined in the near term as the period from the first cycle to the Mth cycle, and in the long term as the period from the (M+1)th cycle to the fth cycle. and , All are natural numbers.

3. The energy management method for a range-extended electric vehicle according to claim 2, characterized in that, The method also includes: When the vehicle is powered on, the stored average power consumption array of the vehicle is read and the current engine output power benchmark is calculated. After power-on, the vehicle starts running. If the vehicle speed is greater than or equal to the speed threshold and the duration exceeds the time threshold, the average power consumption of the vehicle in a single cycle will be calculated. After each calculation cycle, the average power consumption array of the vehicle and the engine output power benchmark will be updated synchronously and a new calculation cycle will begin until the vehicle is powered off. After the vehicle is powered off, the average power consumption array of the whole vehicle is written into the memory.

4. The energy management method for a range-extended electric vehicle according to claim 3, characterized in that, Methods for calculating the average power consumption of a vehicle within a single cycle include: The average power consumption of the whole vehicle in a single cycle = the average power of the engine in a single calculation cycle - (the change in the remaining charge of the power battery in a single calculation cycle / cycle time).

5. The energy management method for a range-extended electric vehicle according to claim 4, characterized in that, The calculation methods for the engine output power SOC change compensation value include: Calculate the change in SOC of the power battery ΔSOC within the most recent set time in power adaptive mode and low SOC compensation mode. When ΔSOC≥0, obtain the engine output power SOC change compensation value corresponding to the ΔSOC change when SOC rises; The engine output power SOC change compensation value is corrected based on the current SOC of the power battery; The engine output power SOC change compensation value is corrected based on the current engine high-efficiency power range. Output the corrected engine output power SOC change compensation value; When ΔSOC < 0, obtain the engine output power SOC change compensation value corresponding to the decrease in SOC; execution steps: correct the engine output power SOC change compensation value based on the current SOC of the power battery.

6. The energy management method for a range-extended electric vehicle according to claim 5, characterized in that, The calculation methods for the engine output power drive motor compensation value include: The input power reference of the drive motor is obtained by subtracting the power of the auxiliary components from the output power reference of the engine. Subtract the drive motor's input power reference from the real-time input power of the drive motor to obtain the real-time difference in engine output power based on the drive motor's input power. The real-time difference in engine output power is corrected to obtain the compensation value for the engine output power drive motor.

7. The energy management method for a range-extended electric vehicle according to claim 6, characterized in that, The calculation method for the PID compensation value of engine output power includes: Obtain the current SOC and target SOC of the power battery; The difference between the current SOC and the target SOC of the power battery is used to calculate the PID compensation value of the engine output power through a PID algorithm. The PID compensation value for engine output power is corrected based on the current SOC of the power battery and the current high-efficiency power range of the engine. The output power of the engine is based on the PID compensation value of the target SOC.

8. The energy management method for a range-extended electric vehicle according to claim 7, characterized in that, The calculation methods for the engine's high-efficiency power range include: Based on the current operating environment and the operating status of the engine and power battery, obtain the engine power generation efficiency Map and the power battery charge and discharge efficiency Map under different SOCs. The power generation efficiency Map of the vehicle is obtained by multiplying the engine power generation efficiency Map with the charge and discharge efficiency Map of the power battery under different SOCs. By combining the engine output power benchmark, the high-efficiency power range of the engine is obtained by generating the maximum and minimum operating power of the engine.

9. The energy management method for a range-extended electric vehicle according to claim 1, characterized in that, The method also includes: When the average speed of the vehicle is lower than the first threshold and the maximum speed is lower than the second threshold, the vehicle operates in low-speed mode. In low-speed operating mode, the engine output power is set according to the power battery SOC; When the vehicle is running in normal operating mode, if the parking time is detected to be greater than the set time threshold and the power battery charge is not greater than the charging threshold within a single vehicle energy consumption average power calculation cycle, the vehicle enters parking charging mode. In parking charging mode, the engine is set to operate at its highest efficiency power; the parking time is the continuous time during which the vehicle speed is below the vehicle speed threshold. When the vehicle is running in normal operating mode, if a level 2 fault is detected in the engine or power battery, the vehicle will run in level 2 fault mode. In Level 2 fault mode, the engine is set to operate at its highest efficiency power.

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