Dual-motor hybrid system energy management method and system and dual-motor hybrid system

Abstract

This application discloses an energy management method, system, and dual-motor hybrid system for a dual-motor hybrid system, belonging to the field of hybrid vehicle technology. The method includes the following steps: obtaining a target value for the battery state of charge (SOC) of the target road segment based on navigation information and the current SOC of the battery; controlling the engine start or stop of the dual-motor hybrid system based on the current SOC and the target SOC; wherein the engine start includes series mode start and parallel mode start. This application, through the above method, incorporates navigation information of future target road segments into global energy management, avoiding temporary inefficient charging and significantly improving fuel economy. Optimizing the engine start / stop timing based on the current SOC and the target SOC effectively reduces the frequency of start / stop in inefficient areas, thereby improving NVH performance.

Description

Technical Field

[0001] This application relates to the field of hybrid vehicle technology, specifically to a dual-motor hybrid system energy management method, system, and dual-motor hybrid system. Background Technology

[0002] Hybrid vehicle energy management is mostly based on past parameters such as vehicle speed, weight, driver power demand, and battery SOC (State of Charge) for optimal control. However, there is a risk of insufficient energy reserve prediction, leading to situations where the vehicle is charged while driving at high power in urban areas, which worsens fuel economy and NVH (Noise, Vibration, Harshness). Summary of the Invention

[0003] This application provides an energy management method, system, and dual-motor hybrid system for a dual-motor hybrid system. It incorporates future road conditions into the global optimal energy management, improves energy management efficiency, and thereby optimizes the economy and NVH of hybrid vehicles.

[0004] To achieve the above objectives, according to a first aspect of this application, an energy management method for a dual-motor hybrid system is provided, comprising the following steps:

[0005] Based on the navigation information of the target road segment and the current value of the battery state of charge, obtain the target value of the battery state of charge of the target road segment;

[0006] Based on the current value of the battery state of charge and the target value of the battery state of charge, the engine of the dual-motor hybrid system is controlled to start or stop; wherein, the engine starting includes series mode starting and parallel mode starting.

[0007] In some embodiments, obtaining the target value of the battery state of charge for the target road segment based on navigation information and the current value of the battery state of charge includes:

[0008] Based on the navigation information of the target road segment, the target road segment is divided into n sub-segments, and the navigation information of each sub-segment is obtained, where n is a positive integer;

[0009] Based on the navigation information of each road segment, obtain the estimated battery state of charge for each road segment;

[0010] Based on the current value of the battery state of charge and the estimated value of the battery state of charge for the n road segments, the target value of the battery state of charge for the target road segment is obtained.

[0011] In some embodiments, obtaining the estimated battery state of charge for each of the sub-segments based on the navigation information of each sub-segment includes:

[0012] Based on the navigation information of each road segment, the average vehicle speed of each road segment is obtained;

[0013] Based on the average vehicle speed of each road segment, the expected energy consumption of each road segment is obtained;

[0014] Based on the expected energy consumption of each of the sub-segments, the estimated state of charge of the battery for each sub-segment is obtained.

[0015] In some embodiments, obtaining the target value of the battery state of charge for the target road segment based on the current value of the battery state of charge and the estimated values ​​of the battery state of charge for n road segments includes:

[0016] Based on the average vehicle speed and expected energy consumption of each road segment, the energy efficiency level of each road segment is assessed, and the energy efficiency level includes low efficiency range, medium efficiency range, medium-high efficiency range, and high efficiency range.

[0017] For any current sub-segment among all the sub-segments, if the energy efficiency level of the current sub-segment is in the low-efficiency range or the medium-efficiency range, the target value of the battery state of charge is determined as the critical value of insufficient battery state of charge.

[0018] When the energy efficiency level of the current road segment is in the medium-high efficiency range or the high efficiency range, the target value of the battery state of charge is determined as a first battery state of charge value or a second battery state of charge value. The first battery state of charge value is the sum of the estimated battery state of charge values ​​of the candidate road segments and the current battery state of charge value. The second battery state of charge value is the sum of the additional energy stored in the current road segment and the current battery state of charge value. The candidate road segments are those in the target road segment that are in the low efficiency range and / or the medium efficiency range. The additional energy stored in the current road segment is the difference between the total energy of the current road segment in its maximum high efficiency range and the expected energy consumption of the current road segment.

[0019] In some embodiments, when the energy efficiency level of the current branch segment is in the medium-high efficiency range or the high efficiency range, determining the target value of the battery state of charge as a first battery state of charge value or a second battery state of charge value includes:

[0020] If the current branch segment is a branch segment with an energy efficiency level in the medium-high efficiency range or the high efficiency range, and the additional energy stored in the current branch segment exceeds the total energy consumption of the alternative branch segments, the target value of the battery state of charge is determined as the maximum value between the first battery state of charge value and the second battery state of charge value.

[0021] If the current branch segment is a branch segment with an energy efficiency level in the medium-high efficiency range or the high efficiency range, but the total energy consumption of the candidate branch segment exceeds the additional energy stored in the current branch segment, the comprehensive efficiency of the current branch segment and the comprehensive efficiency of the candidate branch segment are obtained.

[0022] If the overall efficiency of the current branch segment is greater than the overall efficiency of the candidate branch segment, the target value of the battery state of charge is determined as the first battery state of charge value.

[0023] If the overall efficiency of the current branch segment is less than the overall efficiency of the alternative branch segment, the target value of the battery state of charge is determined as the second battery state of charge value.

[0024] In some embodiments, when the energy efficiency level of the current branch segment is in the medium-high efficiency range or the high efficiency range, determining the target value of the battery state of charge as a first battery state of charge value or a second battery state of charge value further includes:

[0025] If there are no alternative sub-segments in the target road segment, the target value of the battery state of charge is determined as the maximum value between the second battery state of charge value and the current battery state of charge value; wherein, the additional energy stored in the current sub-segment is the difference between the minimum high-efficiency interval total energy of the current sub-segment and the expected energy consumption of the current sub-segment.

[0026] In some embodiments, controlling the engine start or stop of the dual-motor hybrid system based on the current value of the battery state of charge and the target value of the battery state of charge includes:

[0027] If the current value of the battery state of charge is less than the target value of the battery state of charge, the engine is controlled to start;

[0028] If the current value of the battery state of charge is greater than or equal to the target value of the battery state of charge, the engine is controlled to stop.

[0029] In some embodiments, controlling the engine to start includes:

[0030] Get the vehicle's current speed;

[0031] If the current vehicle speed is less than the vehicle speed corresponding to the lowest engine speed in the parallel mode, the engine is controlled to enter the series mode for startup.

[0032] When the current vehicle speed is greater than or equal to the vehicle speed corresponding to the lowest engine speed in the parallel mode, and the target value of the battery state of charge is greater than the current value of the battery state of charge, the engine is controlled to enter the parallel mode for startup.

[0033] In some embodiments, controlling the engine to start in series mode includes:

[0034] Determine the total power requirement of the entire vehicle;

[0035] Based on the total power demand of the vehicle, the optimal power generation point of the engine in series mode is determined;

[0036] Based on the optimal power generation point, the target speed and target torque of the engine are determined.

[0037] In some embodiments, controlling the engine to enter parallel mode for startup includes:

[0038] Determine the total power requirement of the entire vehicle;

[0039] The optimal efficiency range of the engine is determined based on the universal characteristic diagram of the engine.

[0040] Based on the current vehicle speed and the optimal efficiency range, determine the maximum torque at the current vehicle speed;

[0041] Based on the current vehicle speed and the total power demand of the vehicle, determine the expected torque of the current engine;

[0042] The target torque of the engine is determined based on the maximum torque and the expected torque.

[0043] In some embodiments, after controlling the engine to start, the method further includes: switching modes within the target road segment;

[0044] The mode switching within the target road segment includes:

[0045] Control the engine to maintain its current power;

[0046] Control the engine torque to reduce to the minimum torque required for mode switching;

[0047] The allowable charging and discharging power of the motor connected to the engine drive increases from zero to its maximum value;

[0048] Obtain the current allowable charging and discharging power of the entire vehicle;

[0049] Based on the vehicle's permissible charging and discharging power and the motor's permissible charging and discharging power, the charging and discharging power during the mode switching process is obtained, wherein the charging and discharging power during the mode switching process is the difference between the vehicle's permissible charging and discharging power and the motor's permissible charging and discharging power.

[0050] According to a second aspect of this application, a dual-motor hybrid system energy management system is provided, comprising:

[0051] The acquisition unit is used to acquire the target value of the battery state of charge of the target road segment based on the navigation information of the target road segment and the current value of the battery state of charge.

[0052] The control unit is used to control the start or stop of the engine of the dual-motor hybrid system based on the current value of the battery state of charge and the target value of the battery state of charge, wherein the engine start includes series mode start and parallel mode start.

[0053] According to a third aspect of this application, a dual-motor hybrid system is provided, applied to the energy management method of the dual-motor hybrid system described in any of the foregoing embodiments. The dual-motor hybrid system includes: an engine, a first motor, a second motor, a first clutch, and a second clutch. The output end of the engine is drivenly connected to the input end of the first clutch. The output end of the first motor is drivenly connected to the output end of the first clutch and the input end of the second clutch, respectively. The output end of the second motor is drivenly connected to the output end of the second clutch and the front axle wheel of the vehicle, respectively.

[0054] This application provides an energy management method, system, and dual-motor hybrid system for a dual-motor hybrid system. The method includes the following steps: obtaining a target value for the battery state of charge (SBC) of the target road segment based on navigation information and the current SBC value; and controlling the engine start or stop of the dual-motor hybrid system based on the current SBC value and the target SBC value. The engine start includes series mode start and parallel mode start. This application, through the above method, can determine the target SBC value for the future target road segment based on navigation information and the current SBC value, and then rationally control the engine start / stop accordingly. It switches between pure electric, series, and parallel modes based on energy consumption requirements, achieving better energy management. By incorporating the navigation information of the future target road segment into global energy management, temporary inefficient charging can be avoided, significantly improving economy. Optimizing the engine start / stop timing based on the current SBC value and the target SBC value effectively reduces the frequency of start / stop in inefficient areas, thereby improving NVH performance. Attached Figure Description

[0055] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0056] Figure 1This is a flowchart illustrating an energy management method for a dual-motor hybrid system provided in some embodiments of this application;

[0057] Figure 2 This is a schematic flowchart of step S100 of an energy management method for a dual-motor hybrid system provided in some embodiments of this application;

[0058] Figure 3 This is a schematic flowchart of step S120 of an energy management method for a dual-motor hybrid system provided in some embodiments of this application;

[0059] Figure 4 This is a schematic flowchart of step S130 of an energy management method for a dual-motor hybrid system provided in some embodiments of this application;

[0060] Figure 5 This is a schematic flowchart of step S133 of an energy management method for a dual-motor hybrid system provided in some embodiments of this application;

[0061] Figure 6 This is a schematic flowchart of step S200 of an energy management method for a dual-motor hybrid system provided in some embodiments of this application;

[0062] Figure 7 This is a schematic flowchart of step S210 of an energy management method for a dual-motor hybrid system provided in some embodiments of this application;

[0063] Figure 8 This is a schematic flowchart of step S213 of an energy management method for a dual-motor hybrid system provided in some embodiments of this application;

[0064] Figure 9 This is a detailed flowchart illustrating step S214 of an energy management method for a dual-motor hybrid system provided in some embodiments of this application;

[0065] Figure 10 This is another schematic flowchart of an energy management method for a dual-motor hybrid system provided in some embodiments of this application;

[0066] Figure 11 This is a schematic flowchart of step S300 of an energy management method for a dual-motor hybrid system provided in some embodiments of this application;

[0067] Figure 12 This is a structural diagram of a dual-motor hybrid system provided in some embodiments of this application;

[0068] Figure 13 This is a structural diagram of an energy management system for a dual-motor hybrid system provided in some embodiments of this application.

[0069] Explanation of reference numerals in the attached figures:

[0070] 1. Engine; 2. First motor; 3. Second motor; 4. First clutch; 5. Second clutch; 6. Front axle wheel; 7. Acquisition unit; 8. Control unit. Detailed Implementation

[0071] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0072] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0073] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0074] The use of "applies to" or "configured to" in this application implies open and inclusive language, which does not exclude the applicability to or configuration to devices performing additional tasks or steps. Additionally, the use of "based on" implies openness and inclusivity, because processes, steps, calculations, or other actions "based on" one or more of the stated conditions or values ​​may in practice be based on additional conditions or values ​​beyond those stated.

[0075] In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use this application. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be made without using these specific details. In other instances, well-known structures and processes are not described in detail to avoid obscuring the description of this application with unnecessary detail. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0076] In related technologies, hybrid vehicle energy management is mostly based on current real-time parameters such as vehicle speed, weight, driver power demand, and battery state of charge for optimal control. It does not take future road conditions into account in the global optimal energy management, which may lead to insufficient energy reserves and situations where the vehicle is charged while driving at high power in urban areas, thus worsening economy and NVH. Moreover, most of these technologies mainly consider the optimal efficiency of the engine itself, without considering the optimal performance of the entire hybrid system (motor + engine), resulting in "oil at optimal efficiency becoming electricity at the worst efficiency", and the overall energy consumption is not ideal.

[0077] In view of this, embodiments of this application provide an energy management method, system, and dual-motor hybrid system for a dual-motor hybrid system, aiming to solve at least one of the above problems.

[0078] According to a first aspect of this application, an energy management method for a dual-motor hybrid system is provided, such as... Figure 1 As shown, it includes the following steps:

[0079] S100: Based on the navigation information of the target road segment and the current value of the battery state of charge, obtain the target value of the battery state of charge for the target road segment.

[0080] In this step, the current state of charge (SOC) of the battery is the current SOC, and the target SOC is the target SOC. By combining future road conditions with energy reserve targets, the current lack of global planning is addressed, forming the global decision-making basis for energy management in this application's embodiments. This effectively avoids the problem of insufficient energy reserve prediction.

[0081] The core value of navigation information lies in providing energy consumption influencing factors for the target route, including but not limited to:

[0082] Road type (highway / urban / suburban): Highways (e.g., 120 kph) are in the high-efficiency range of the system, where the engine and dual motors work together efficiently; urban areas (e.g., 20 kph congestion) are in the low-efficiency range of the system, where the engine alone is inefficient.

[0083] Traffic congestion (no / mild / severe): Congestion increases energy consumption due to frequent acceleration and deceleration, requiring additional reserve power.

[0084] Gradient / Elevation: Energy consumption increases sharply on uphill sections, so it is necessary to replenish energy in advance to avoid running out of power midway.

[0085] S200: Based on the current value of the battery state of charge and the target value of the battery state of charge, control the engine of the dual-motor hybrid system to start or stop; wherein, the engine start includes series mode start and parallel mode start.

[0086] In this step, by setting energy targets, the engine start-stop is precisely controlled to minimize inefficient engine operation in the inefficient range, thereby improving engine efficiency and ensuring that energy reserves meet the targets.

[0087] In this embodiment, based on navigation information of the future target road segment and the current battery state of charge (SBC), a target SBC value for the future target road segment can be determined. This allows for corresponding and reasonable control of engine start-stop, switching between pure electric, series, and parallel modes according to energy consumption demands, achieving better energy management. By incorporating navigation information of the future target road segment into global energy management, temporary inefficient charging can be avoided, significantly improving fuel economy. Optimizing engine start-stop timing based on the current and target SBC values ​​effectively reduces the frequency of start-stop cycles in inefficient zones, thereby improving NVH performance. Simultaneously, it optimizes system efficiency, preventing the waste of high-efficiency engine fuel converted into inefficient electric motor power, effectively improving overall energy efficiency. Furthermore, optimizing the target SBC value reduces the possibility of power interruption due to insufficient battery charge, ensuring power continuity and enhancing the driving experience.

[0088] like Figure 2 As shown, in some embodiments, based on the navigation information of the target road segment and the current value of the battery state of charge, a target value of the battery state of charge for the target road segment is obtained, including:

[0089] S110: Based on the navigation information of the target road segment, divide the target road segment into n sub-segments and obtain the navigation information of each sub-segment, where n is a positive integer.

[0090] In this step, by dividing the target road segment into n sub-segments and obtaining the corresponding navigation information for each sub-segment, complex road conditions can be broken down into smaller segments. Specifically, road segments can be divided according to differences in road conditions, thereby enabling a more accurate determination of factors affecting energy consumption.

[0091] The main basis for segmentation is the difference in navigation information characteristics of the target road segments, specifically including but not limited to: changes in road type (e.g., highway to suburban to urban, the energy consumption of the three types of road segments differs significantly and needs to be segmented), changes in congestion level (e.g., no congestion to slight congestion to severe congestion, congestion increases acceleration and deceleration energy consumption and needs to be segmented), and changes in gradient / altitude (e.g., flat road to uphill to downhill, uphill will increase energy consumption and needs to be segmented). The main segmentation principle is: n is a positive integer, the more complex the road conditions, the greater the difference, and the larger the corresponding value of n. For example, a cross-city road segment may be segmented into 5 segments, and a single highway segment into 1 segment, ensuring that the navigation information characteristics within each segment are consistent. For example, a segment may be characterized as all highways, no congestion, and flat roads. The corresponding output is the exclusive navigation information for each segment, such as segment N1 being a highway, no congestion, flat road segment, and segment N2 being an urban, severely congested, and slightly uphill road segment.

[0092] This application effectively avoids energy consumption prediction errors caused by mixing the conditions of the entire road segment by dividing the target road segment into sections.

[0093] S120: Based on the navigation information of each road segment, obtain the estimated battery state of charge for each road segment.

[0094] In this step, the estimated state of charge of the battery is denoted as δSOC. By dividing the target road segment into parts and obtaining the estimated state of charge of the battery for each segment, a more accurate prediction result can be obtained, thus providing a more accurate reference for subsequent energy management.

[0095] like Figure 3 As shown, in some embodiments, S120: Based on the navigation information of each road segment, obtain the estimated battery state of charge for each road segment, specifically including the following steps:

[0096] S121: Based on the navigation information of each road segment, obtain the average vehicle speed of each road segment.

[0097] In this embodiment of the application, by obtaining the navigation information of each road segment, the average vehicle speed reference value of each road segment can be calculated more accurately, thereby avoiding the vehicle speed estimation deviation caused by the mixed calculation of multiple road segments, and thus reducing the deviation of energy consumption management.

[0098] The specific method for obtaining average vehicle speed includes: based on the navigation information of each road segment, obtaining the road type and congestion status of each road segment; then determining the base vehicle speed for each road segment based on the road type; and finally, adjusting the base vehicle speed according to the congestion status to determine the average vehicle speed for each road segment.

[0099] S122: Based on the average vehicle speed of each road segment, obtain the expected energy consumption of each road segment.

[0100] In this embodiment, the expected energy consumption mainly refers to the future electricity consumption demand of each road segment. This expected energy consumption is calculated as vehicle speed × resistance torque + accessory power + gradient + coefficient correction (for uphill sections due to altitude, etc.). Specifically, it can be summarized as follows:

[0101] (1) Basic driving energy consumption: It is directly determined by the average vehicle speed. The formula is: Basic energy consumption = average vehicle speed × vehicle resistance torque. Resistance torque includes rolling resistance torque (positively correlated with vehicle speed, with a high proportion at low speeds) and wind resistance torque (positively correlated with the square of vehicle speed, with a high proportion at high speeds). For example, the wind resistance torque at 110kph high speed is much greater than that at 25kph urban area, and the basic energy consumption is higher for the former.

[0102] (2) Fixed accessory energy consumption: It does not change with vehicle speed, but must be included in the total energy consumption, including DC-DC power (DC to DC power, powering the low-voltage battery) + air conditioning power (cooling / heating) + power of other electrical accessories (power steering, brake vacuum pump). For example, when the air conditioning is on in summer, accessory energy consumption increases by 5~8kWh / 100km.

[0103] (3) Road condition correction energy consumption: Based on the slope adjustment in the navigation information, when going uphill, additional slope resistance energy consumption is required (e.g., 10~15kWh / 100km is added for a 10° uphill slope), and energy consumption is reduced when going downhill (or even energy is recovered, resulting in negative energy consumption).

[0104] S123: Based on the expected energy consumption of each sub-segment, obtain the estimated state of charge of the battery for each sub-segment.

[0105] In this embodiment, the δSOC of a road segment is calculated as: (Expected energy consumption of the road segment / Battery capacity) × 100%. For example, if the expected energy consumption of a road segment is 8 kWh and the total battery capacity of the vehicle is 20 kWh, then the δSOC of that road segment is 8 ÷ 20 × 100% = 40%; if the expected energy consumption is 15 kWh and the total battery capacity is 20 kWh, then the δSOC of that road segment is 75%.

[0106] Through steps S121-S123, vehicle speed is first quantified, then energy consumption is quantified, and finally battery SOC is quantified. This enables an effective conversion from future road conditions to SOC estimates, effectively improving the accuracy of energy consumption prediction and avoiding excessive or insufficient SOC reserves. At the same time, the SOC estimates are more closely matched with actual usage scenarios, effectively improving economy and providing more precise command support for subsequent global energy planning and engine start-stop, which is conducive to improving NVH and power continuity.

[0107] S130: Based on the current battery state of charge and the estimated battery state of charge for n road segments, obtain the target battery state of charge for the target road segment.

[0108] This step mainly involves combining the energy consumption requirements of the entire target road segment with the current battery charge level to obtain a more accurate target value for the battery's state of charge, thereby enabling more precise control of the engine's start and stop.

[0109] In this embodiment, the execution of the above steps effectively improves the accuracy of energy consumption prediction, avoids insufficient or excessive energy reserves, and makes the target SOC more consistent with overall road condition efficiency, maximizing economic benefits. It also provides more precise control basis for subsequent engine start-stop and is conducive to improving NVH performance. Furthermore, it is applicable to multi-road condition scenarios, enhancing the anti-interference capability of energy management.

[0110] like Figure 4 As shown, in some embodiments, based on the current battery state of charge (SBC) value and the estimated SBC values ​​of the n road segments, a target SBC value for the target road segment is obtained, including:

[0111] S131: Based on the average vehicle speed and expected energy consumption of each road segment, assess the energy efficiency level of each road segment. The energy efficiency levels include low efficiency range, medium efficiency range, medium-high efficiency range, and high efficiency range.

[0112] In this embodiment of the application, by dividing each road segment into energy efficiency levels, it is equivalent to classifying and labeling each road segment, providing a basis for judgment on the subsequent differentiated target SOC.

[0113] The energy efficiency rating is based on the following criteria: the average vehicle speed on each road segment determines the basic efficiency of the hybrid system, and the expected energy consumption determines the intensity of energy consumption. Combining the two can accurately determine whether the road segment is suitable for energy storage.

[0114] The specific energy efficiency rating standards are as follows:

[0115] Inefficient range: average vehicle speed ≤30kph (such as urban congestion), and acceleration and deceleration losses account for ≥40% of expected energy consumption. At this time, the engine is prone to low speed and high load (efficiency <25%), and the electric motor drive efficiency is also low.

[0116] Medium efficiency range: average vehicle speed 30~60kph (such as suburban roads), and the expected energy consumption includes acceleration and deceleration losses accounting for 20%~40%. At this time, the engine efficiency is 25%~35%, and the electric motor drive efficiency is moderate.

[0117] Medium-high efficiency range: average vehicle speed 60~90kph (such as urban expressway), and the proportion of uniform speed loss in expected energy consumption ≥60%. At this time, the engine efficiency is 35%~40%, and the series-parallel system has high efficiency.

[0118] High efficiency range: average vehicle speed ≥ 90 kph (such as high speed), and the proportion of uniform speed loss in expected energy consumption ≥ 80%, and the engine is likely to fall into the optimal region of the universal characteristic diagram. At this time, the engine efficiency is ≥ 40%, and the parallel system has the highest efficiency.

[0119] Step S131 uses the above-mentioned classification criteria to classify energy efficiency levels, allowing the system to clearly identify which sub-segments are suitable for energy storage and which sub-segments only need to maintain power supply. This provides a clear judgment standard for subsequent differentiated strategies and avoids a disconnect between energy efficiency strategies and actual efficiency.

[0120] S132: For any current sub-segment among all sub-segments, if the energy efficiency level of the current sub-segment is in the low-efficiency range or the medium-efficiency range, the target value of the battery state of charge is determined as the critical value of insufficient battery state of charge.

[0121] In this embodiment, the insufficient state of charge (SOC) threshold of the battery can be the SOC threshold for conventional engine starting, such as a battery SOC of 15%. This is the minimum limit at which the battery is about to run out of power and the engine must be started to maintain power. Below this value, power loss will occur; above this value, there is no need to start the engine. In step S132, if the current road segment is in an inefficient / medium-efficient range (low system efficiency), then the target SOC = the threshold value. This means that no additional energy is stored, and as long as the battery SOC is not lower than the threshold value, pure electric driving is maintained, avoiding starting the engine to charge in the inefficient range. Therefore, it can avoid deterioration of NVH and reduce ineffective energy consumption.

[0122] S133: When the energy efficiency level of the current road segment is in the medium-high efficiency range or the high efficiency range, the target value of the battery state of charge is determined as the first battery state of charge value or the second battery state of charge value. The first battery state of charge value is the sum of the estimated battery state of charge values ​​of the candidate road segments and the current battery state of charge value. The second battery state of charge value is the sum of the additional energy stored in the current road segment and the current battery state of charge value. The candidate road segments are the road segments in the target road segment that are in the low efficiency range and / or medium efficiency range. The additional energy stored in the current road segment is the difference between the total energy of the maximum high efficiency range of the current road segment and the expected energy consumption of the current road segment.

[0123] In this embodiment, the first battery state of charge (SOC) value primarily covers the needs of subsequent alternative route segments, while the second battery SOC value refers to the current maximum energy storage capacity. By dynamically selecting the first and second battery SOC values, it ensures that the high-efficiency range is prioritized for storing subsequent low-efficiency energy while avoiding exceeding the current storage capacity or inverting efficiency, thus maximizing the storage benefits of the high-efficiency range.

[0124] The embodiments of this application, through the above steps, can effectively improve the accuracy of energy planning and minimize inefficient charging and excessive storage. Simultaneously, it optimizes the engine's operating range, significantly improving fuel economy and NVH performance. Furthermore, it adapts to more complex road conditions, making energy management more precise. It can also indirectly extend battery life.

[0125] like Figure 5 As shown, in some embodiments, when the energy efficiency level of the current branch segment is in the medium-high efficiency range or the high efficiency range, the target value of the battery state of charge is determined as a first battery state of charge value or a second battery state of charge value, including:

[0126] S1331: When the current sub-segment is a sub-segment with an energy efficiency level in the medium-high efficiency range or the high efficiency range, and the additional energy stored in the current sub-segment exceeds the total energy consumption of the alternative sub-segments, the target value of the battery state of charge is determined as the maximum value between the first battery state of charge value and the second battery state of charge value.

[0127] In this step, if the additional energy stored in the current branch (after conversion to SOC) is greater than or equal to the total energy consumption of the alternative branch (the total δSOC of the alternative branch), then the current branch has sufficient capacity to store the energy required for the future and may have additional redundancy. In this case, the first battery charge state value is selected as the target SOC. On the one hand, this avoids the need to replenish energy in the subsequent alternative branch, which is beneficial to improving economic efficiency. On the other hand, it utilizes the redundancy capacity of the current branch, which is in the medium-high efficiency range or the high efficiency range, to store more electricity. In this case, if there is a sudden high energy consumption demand in the future, there is no need to start up.

[0128] S1332: When the current road segment is in the medium-high energy efficiency range or the high energy efficiency range, but the total energy consumption of the alternative road segments exceeds the extra energy stored in the current road segment, obtain the comprehensive efficiency of the current road segment and the comprehensive efficiency of the alternative road segments.

[0129] S1333: If the overall efficiency of the current sub-segment is greater than the overall efficiency of the alternative sub-segment, the target value of the battery state of charge is determined as the first battery state of charge value.

[0130] S1334: If the overall efficiency of the current sub-segment is less than the overall efficiency of the alternative sub-segment, the target value of the battery state of charge is determined as the second battery state of charge value.

[0131] Through steps S1332 to S1334, when the current energy efficiency segment is in the medium-high efficiency or high efficiency range, but the total energy consumption of the alternative energy segments exceeds the additional energy stored in the current segment, the target State of Charge (SOC) is determined by comparing the overall efficiency of the current segment with that of the alternative energy segments. This dual-dimensional assessment of energy storage capacity and efficiency further reduces the deviation from the target SOC, thereby improving the accuracy of energy management. Simultaneously, it directs energy storage towards the medium-high efficiency or high efficiency range as much as possible, maximizing economic efficiency and indirectly extending battery life.

[0132] like Figure 5 As shown, in one embodiment, when the energy efficiency level of the current branch segment is in the medium-high efficiency range or the high efficiency range, determining the target value of the battery state of charge as a first battery state of charge value or a second battery state of charge value further includes:

[0133] S1335: In the absence of alternative sub-segments in the target road segment, the target value of the battery state of charge is determined as the maximum value between the second battery state of charge value and the current battery state of charge value; wherein, the additional energy stored in the current sub-segment is the difference between the minimum high-efficiency interval total energy of the current sub-segment and the expected energy consumption of the current sub-segment.

[0134] In this embodiment, if there are no alternative sub-segments for the target road segment, i.e., the target road segments are all in the medium-high efficiency range and / or high efficiency range, the energy management strategy at this time is to ensure the current high efficiency with the minimum high efficiency total energy, and to avoid excessive storage by not exceeding the sum of the current SOC and the extra energy, thereby reducing energy waste and battery wear; at the same time, to ensure that the current sub-segment does not leave the high efficiency range, to maintain the system's high efficiency operation, and to reduce fuel consumption; in addition, to avoid the target SOC from being lower than the current SOC, to ensure power continuity and energy stability.

[0135] In addition, the embodiments of this application use the maximum value between the second battery state of charge value and the current battery state of charge value to limit the target SOC, which can avoid meaningless discharge and reserve power to meet sudden demand.

[0136] It should be noted that the maximum total energy in the high-efficiency range of this application embodiment is the upper limit of energy reserve in the high-efficiency range. Specifically, within the current high-efficiency / medium-high-efficiency range, when the hybrid system (engine + dual motors + battery working together) is in its optimal efficiency state (e.g., engine efficiency ≥ 40%, system overall efficiency ≥ 35%), the maximum total energy that can be output is the maximum usable energy within the high-efficiency range. This can be understood as the maximum amount of energy (including driving the vehicle and additional reserves) that can be generated on the current road segment without deviating from high-efficiency operation. The specific calculation logic is based on the optimal efficiency of the engine's universal characteristic map plus the dual motor efficiency MAP (MAP is short for Characteristic Map), plus the optimal power range corresponding to the current vehicle speed. For example: The current road segment is a highway (high-efficiency range), with an average vehicle speed of 120 kph. The system's high-efficiency power range is 40~60 kW (efficiency will decrease below 40 kW or above 60 kW). The road segment is 100 km long (estimated travel time is 1 hour). The corresponding maximum high-efficiency range total energy = high-efficiency power limit × time = 60 kW × 1 h = 60 kWh. That is, the current road segment can generate a maximum of 60 kWh of energy in high-efficiency mode, including the energy consumption for driving the vehicle and the additional energy that can be stored.

[0137] The minimum total energy required for the high-efficiency range in this application embodiment is the lower limit of energy demand to maintain high efficiency. Specifically, it refers to the minimum total energy demand that the hybrid system must meet to maintain a high-efficiency operating state (without falling into the inefficient zone) within the current high-efficiency range or medium-high-efficiency range. Below this value, the system will deviate from high efficiency and enter inefficient operation. In other words, it is the minimum amount of energy required for the current road segment to maintain high efficiency, including driving the vehicle and basic reserves. For example: the current road segment is a highway (high-efficiency range), with an average vehicle speed of 120 kph, and the system's high-efficiency power range is 40~60 kW (efficiency will decrease below 40 kW or above 60 kW). The road segment length is 100 km (estimated travel time is 1 hour). The corresponding minimum total energy required for the high-efficiency range = lower limit of high-efficiency power × time = 40 kW × 1 h = 40 kWh. That is, at least 40 kWh of energy is required for the current road segment to maintain high efficiency throughout the journey; below this value, it will become inefficient.

[0138] like Figure 6 As shown, in some embodiments, the engine of the dual-motor hybrid system is controlled to start or stop based on the current value of the battery state of charge and the target value of the battery state of charge, including:

[0139] S210: If the current value of the battery state of charge is less than the target value of the battery state of charge, control the engine to start.

[0140] In this step, controlling the engine to start when the current SOC is less than the target SOC can avoid the problem of insufficient energy reserves in the early stage and inefficient energy replenishment in the later stage. It ensures that energy replenishment is completed in the medium-high efficiency or high efficiency range, reduces high fuel consumption scenarios of inefficient energy replenishment, and thus optimizes energy management efficiency.

[0141] S220: If the current value of the battery state of charge is greater than or equal to the target value of the battery state of charge, control the engine to stop.

[0142] In this embodiment of the application, the engine is controlled not to start when the current SOC is greater than or equal to the target SOC. This can be understood as not starting the engine when there is enough power. The engine running time is precisely controlled so as not to waste energy and to prevent the engine from leaving the high-efficiency zone.

[0143] In this embodiment, the engine start-up decision is made by comparing the current SOC of the battery with the target SOC. This effectively controls battery charge and engine energy consumption, improving the energy management efficiency of the dual-motor hybrid system and optimizing fuel economy and NVH performance. Simultaneously, proper engine start-stop control enhances ride smoothness and reduces frequent engine start-stop operations; it also prevents battery overcharging and deep discharging, extending battery life. Furthermore, the engine start-stop logic in this application is indirect, has a low execution threshold, is easy to implement during vehicle operation, and offers a fast response time.

[0144] In some embodiments, the dual-motor hybrid system has a series mode and a parallel mode. The engine start-up includes both series mode start-up and parallel mode start-up.

[0145] like Figure 7 As shown, controlling engine start includes:

[0146] S211: Obtain the vehicle's current speed. By obtaining the current speed, objective operating conditions are provided for subsequent mode selection, avoiding the problem of mode and speed mismatch from the source.

[0147] S212: When the current vehicle speed is lower than the vehicle speed corresponding to the lowest engine speed in parallel mode, control the engine to start in series mode. By starting in series mode, the engine generates electricity but does not drive at low speeds, thus maintaining the engine's efficient speed and avoiding mechanical jerking.

[0148] S213: When the current vehicle speed is greater than or equal to the vehicle speed corresponding to the lowest engine speed in parallel mode, and the target value of the battery state of charge is greater than the current value of the battery state of charge, control the engine to enter parallel mode for startup. By starting in parallel mode, the energy conversion steps are reduced during high-speed refueling.

[0149] In this embodiment, steps S211 to S213 refine the selection of the engine start-up mode. The core principle is to match the optimal start-up mode to the current vehicle speed. The series mode is suitable for low speeds, while the parallel mode is suitable for high speeds, ensuring the engine operates in its high-efficiency range from start-up. This effectively avoids inefficiency or jerking caused by the start-up mode being out of sync with vehicle speed. Simultaneously, it reduces energy conversion losses, improves fuel economy, and reduces inefficient wear on the engine and motor, thus extending the system lifespan of the dual-motor hybrid system. Furthermore, this embodiment, by controlling the engine's operating mode at different speeds, can cover all start-up scenarios from low to high speeds.

[0150] It should be noted that in parallel operation, the engine is directly connected to the drive wheels via mechanical structures such as clutches and gear sets. In this case, vehicle speed and engine speed are rigidly linked. Therefore, there is a fixed proportional relationship between engine speed and current vehicle speed: Engine speed = Current vehicle speed × Gear ratio × (3.6 × 1000) / (π × Wheel diameter), where 3.6 is the conversion factor between km / h and m / s, and π × Wheel diameter is the wheel circumference in meters.

[0151] The minimum parallel engine speed in this embodiment is the minimum speed at which the engine can drive directly at high efficiency. Below this speed, the engine efficiency will drop sharply.

[0152] When the current vehicle speed is less than the speed corresponding to the lowest parallel engine speed, the corresponding engine speed is less than the lowest parallel engine speed, and the engine is in an inefficient zone. If parallel connection is forcibly performed at this time, fuel consumption will soar due to engine inefficiency. Therefore, series mode is required. In this mode, the engine only generates electricity to maintain an efficient speed.

[0153] When the current vehicle speed is greater than or equal to the vehicle speed corresponding to the lowest parallel engine speed, the corresponding engine speed is greater than or equal to the lowest parallel engine speed. The engine enters the high-efficiency zone and has the efficiency basis for parallel direct drive. At this time, the series and parallel efficiency can be compared according to the relationship between the target SOC and the current SOC to further select the mode. For example, when the target SOC is greater than the current SOC, the parallel mode can be selected for startup.

[0154] like Figure 8 As shown, in some embodiments, controlling the engine to enter series mode for startup includes:

[0155] S2131: Determine the total power requirement of the vehicle.

[0156] In this embodiment of the application, by determining the total power demand of the entire vehicle, it is clear how much power needs to be generated, thus avoiding insufficient or excessive power generation.

[0157] Specifically, the total power demand of the vehicle = target charging power + vehicle drive power demand + accessory power. The current vehicle drive power demand is calculated based on the driver's wheel-end torque demand and real-time vehicle speed. The driver's wheel-end torque demand used in the calculation refers to the unfiltered, true wheel-end torque demanded by the pedal, adaptive cruise control, and speed limit torque. Accessory power = DC-DC power + air conditioning power + other electric accessory power. Based on the target SOC, current SOC, and current vehicle speed, the target charging power for the current and a certain future timeframe is calculated through table lookup and correction. Table lookup refers to consulting a MAP chart, and correction refers to adjusting the base charging power obtained from the table based on real-time dynamic factors to eliminate deviations between theoretical values ​​and actual operating conditions. These real-time factors are variables that cannot be fully covered by tables (such as environmental changes and component degradation). The purpose of correction is to ensure that the charging power can still be executed efficiently and safely in real-world scenarios.

[0158] S2132: Based on the total power demand of the vehicle, determine the optimal power generation point of the engine in series mode.

[0159] In this embodiment of the application, the optimal power generation speed / torque point at each power point is determined based on the efficiency map of the range extender system (engine + generator), and the optimal power generation point corresponding to the total power demand of the vehicle is queried.

[0160] S2133: Determine the target speed and target torque of the engine based on the optimal power generation point.

[0161] In this embodiment, the corresponding power generation point is determined based on the total power demand of the vehicle, and then the power generation point is decoupled into the speed and torque corresponding to the range extender system (the range extender power generation is limited to the NVH line and the maximum allowable charging power of the battery, and is not superimposed on the drive end (i.e. the motor can only use the maximum discharge power of the battery)).

[0162] In this embodiment, engine power (P) = speed (n) × torque (T) × constant (related to unit conversion). Under a fixed power, there exists a unique combination of speed and torque, corresponding to the optimal power generation point, which can be determined by the engine's universal characteristic diagram. The speed and torque at the optimal power generation point when the engine is in series mode are the target speed and target torque in series mode.

[0163] This application utilizes energy management by controlling the generator to start in series mode. This maximizes engine efficiency in series mode, reduces fuel consumption, achieves energy supply and demand balance, and avoids ineffective battery charging and discharging. Simultaneously, because the engine always operates at its optimal speed and torque combination, it improves engine stability and reduces mechanical wear.

[0164] It should be noted that under special circumstances, when the battery's charging and discharging power is low, the range extender power can exceed the battery's allowed charging power limit, and the range extender power can be superimposed on the drive end (the maximum drive power that the motor can use is the battery power + range extender power).

[0165] like Figure 9 As shown, in some embodiments, controlling the engine to enter parallel mode for startup includes:

[0166] S2141: Determine the total power requirement of the vehicle.

[0167] S2142: Determine the optimal efficiency range of the engine based on the engine's universal characteristic diagram.

[0168] S2143: Determine the maximum torque at the current vehicle speed based on the current vehicle speed and the optimal efficiency range.

[0169] S2144: Determine the expected torque of the engine based on the current vehicle speed and the total power demand of the vehicle.

[0170] S2145: Determine the target torque of the engine based on the maximum torque and the expected torque.

[0171] In this embodiment, the total power demand of the vehicle = accessory power + target charging power + vehicle drive demand power. Wherein, accessory power = DC-DC power + air conditioning power + power of other electrical accessories. Target charging power calculation: Based on the target SOC, current SOC, and current vehicle speed, the target charging power for the current and future timeframes is calculated using a lookup table and correction. Vehicle drive demand power calculation: The current vehicle drive demand power is calculated based on the driver's wheel-end torque demand and real-time vehicle speed. The driver's torque demand used in the calculation refers to the unfiltered, actual wheel-end torque demanded by the driver, such as pedal torque, adaptive cruise control torque, and speed limit torque.

[0172] Then, the optimal efficiency range [minimum engine power, maximum engine power] is determined based on the engine universal characteristic diagram. Furthermore, the maximum torque at the current vehicle speed is obtained based on the real-time vehicle speed. At the same time, the optimal efficiency range and maximum torque are corrected based on changes in external environment such as atmospheric pressure, gradient, and battery SOC to ensure maximum engine output.

[0173] Finally, the expected torque of the engine at the current vehicle speed is calculated based on the current vehicle speed and the total power demand of the vehicle. If the expected torque is less than the maximum torque, the engine target torque is the expected torque; otherwise, it is the maximum torque.

[0174] In this embodiment of the application, since the engine and wheels are rigidly bound in parallel mode, and the engine speed is strongly correlated with the wheel speed, only the target torque of the engine needs to be determined in parallel mode.

[0175] This application embodiment, by controlling the energy management method in parallel mode, can maximize the engine driving efficiency in parallel mode, significantly reduce fuel consumption in parallel mode, and accurately match power output to demand, avoiding excessive or insufficient power. At the same time, the engine operating stability is improved, reducing mechanical wear and the risk of failure.

[0176] like Figure 10 As shown, in some embodiments, after controlling the engine to start, the method further includes:

[0177] S300: Switch modes within the target road segment.

[0178] like Figure 11 As shown, mode switching within the target road segment includes:

[0179] S310: Controls the engine to maintain its current power. This prevents sudden changes in total power during mode switching, which is fundamental to a smooth transition.

[0180] S320: Controls engine torque to reduce it to the minimum torque required for mode switching. By reducing engine torque to the safe threshold for mode switching (minimum torque required for mode switching), it effectively avoids mechanical shocks during transmission system switching, thereby improving the smoothness of mode switching and significantly reducing mechanical wear.

[0181] S330: Controls the permissible charging and discharging power of the motor connected to the engine drive from zero to its maximum value. In parallel mode, the motor connected to the engine needs to perform both power generation and auxiliary drive functions. When switching modes, it needs to transition from a fixed role to a dynamically adjustable role. Therefore, by gradually increasing the permissible charging and discharging power of the motor through a power ramp-up, current surges caused by sudden motor loading can be avoided, thus enabling gradual energy regulation and a smooth transition of energy flow.

[0182] S340: Obtain the current permissible charging and discharging power of the vehicle. By obtaining the permissible charging and discharging power of the vehicle, the safe upper limit of energy regulation during mode switching can be determined, ensuring that mode switching does not exceed the system hardware capabilities.

[0183] S350: Based on the vehicle's permissible charging and discharging power and the motor's permissible charging and discharging power, the charging and discharging power during mode switching is obtained. This charging and discharging power during mode switching is the difference between the vehicle's permissible charging and discharging power and the motor's permissible charging and discharging power. By calculating this difference, power can be accurately allocated, avoiding energy supply and demand imbalances during switching.

[0184] In this embodiment of the application, steps S310 to S350 specifically define how to perform mode switching. Through the control of the above method, seamless switching of working modes can be achieved, taking into account smoothness, safety and efficiency.

[0185] like Figure 12 As shown, the dual-motor hybrid system of this application embodiment includes an engine 1, a first motor 2, a second motor 3, a first clutch 4, and a second clutch 5. The output end of the engine 1 is driven by the input end of the first clutch 4. The output end of the first motor 2 is driven by both the output end of the first clutch 4 and the input end of the second clutch 5. The output end of the second motor 3 is driven by both the output end of the second clutch 5 and the front axle wheel 6 of the vehicle. By engaging and disengaging the first clutch 4 and the second clutch 5, different operating modes are achieved, thereby realizing different energy utilization. In this application embodiment, by engaging and disengaging the first clutch 4 and the second clutch 5, different operating modes of the engine 1 in the hybrid mode are achieved. For example, when the first clutch 4 is engaged and the second clutch 5 is disengaged, the engine 1 enters a series mode; when both the first clutch 4 and the second clutch 5 are engaged, the engine 1 enters a parallel mode. When the first clutch 4 is disengaged, the engine 1 does not operate.

[0186] like Figure 13 As shown, according to a second aspect of this application, a dual-motor hybrid system energy management system is provided, including an acquisition unit 7 and a control unit 8. The acquisition unit 7 is used to acquire a target value of the battery state of charge for the target road segment based on navigation information of the target road segment and the current value of the battery state of charge. The control unit 8 is used to control the start or stop of the engine 1 of the dual-motor hybrid system based on the current value of the battery state of charge and the target value of the battery state of charge. The engine start includes series mode start and parallel mode start.

[0187] In this embodiment of the application, by cooperating with the acquisition unit 7 and the control unit 8 of the energy management system, precise energy management of the dual-motor hybrid system can be achieved, improving the economy of the vehicle's energy consumption and optimizing the vehicle's NVH performance.

[0188] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0189] The above provides a detailed description of the energy management method, system, and dual-motor hybrid system provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. An energy management method for a dual-motor hybrid system, characterized in that, Includes the following steps: Based on the navigation information of the target road segment, the target road segment is divided into n sub-segments, and the navigation information of each sub-segment is obtained, where n is a positive integer; Based on the navigation information of each road segment, the average vehicle speed of each road segment is obtained; Based on the average vehicle speed of each road segment, the expected energy consumption of each road segment is obtained; Based on the expected energy consumption of each of the sub-segments, obtain the estimated battery state of charge for each of the sub-segments. Based on the current battery state of charge and the estimated battery state of charge of the n road segments, the target battery state of charge of the target road segment is obtained. Based on the average vehicle speed and expected energy consumption of each road segment, the energy efficiency level of each road segment is assessed, and the energy efficiency level includes low efficiency range, medium efficiency range, medium-high efficiency range, and high efficiency range. For any current sub-segment among all the sub-segments, if the energy efficiency level of the current sub-segment is in the low-efficiency range or the medium-efficiency range, the target value of the battery state of charge is determined as the critical value of insufficient battery state of charge. When the energy efficiency level of the current road segment is in the medium-high efficiency range or the high efficiency range, the target value of the battery state of charge is determined as a first battery state of charge value or a second battery state of charge value. The first battery state of charge value is the sum of the estimated battery state of charge values ​​of the candidate road segments and the current battery state of charge value. The second battery state of charge value is the sum of the additional energy stored in the current road segment and the current battery state of charge value. The candidate road segments are the road segments in the target road segment that are in the low efficiency range and / or the medium efficiency range. The additional energy stored in the current road segment is the difference between the total energy of the current road segment in the maximum high efficiency range and the expected energy consumption of the current road segment. Based on the current value of the battery state of charge and the target value of the battery state of charge, the engine of the dual-motor hybrid system is controlled to start or stop; wherein, the engine starting includes series mode starting and parallel mode starting.

2. The energy management method for a dual-motor hybrid system according to claim 1, characterized in that, When the energy efficiency level of the current branch segment is in the medium-high efficiency range or the high efficiency range, the target value of the battery state of charge is determined as a first battery state of charge value or a second battery state of charge value, including: If the current branch segment is a branch segment with an energy efficiency level in the medium-high efficiency range or the high efficiency range, and the additional energy stored in the current branch segment exceeds the total energy consumption of the alternative branch segments, the target value of the battery state of charge is determined as the maximum value between the first battery state of charge value and the second battery state of charge value. If the current branch segment is a branch segment with an energy efficiency level in the medium-high efficiency range or the high efficiency range, but the total energy consumption of the candidate branch segment exceeds the additional energy stored in the current branch segment, the comprehensive efficiency of the current branch segment and the comprehensive efficiency of the candidate branch segment are obtained. If the overall efficiency of the current branch segment is greater than the overall efficiency of the candidate branch segment, the target value of the battery state of charge is determined as the first battery state of charge value. If the overall efficiency of the current branch segment is less than the overall efficiency of the alternative branch segment, the target value of the battery state of charge is determined as the second battery state of charge value.

3. The energy management method for a dual-motor hybrid system according to claim 1, characterized in that, When the energy efficiency level of the current branch segment is in the medium-high efficiency range or the high efficiency range, determining the target value of the battery state of charge as a first battery state of charge value or a second battery state of charge value further includes: If there are no alternative sub-segments in the target road segment, the target value of the battery state of charge is determined as the maximum value between the second battery state of charge value and the current battery state of charge value; wherein, the additional energy stored in the current sub-segment is the difference between the minimum high-efficiency interval total energy of the current sub-segment and the expected energy consumption of the current sub-segment.

4. The energy management method for a dual-motor hybrid system according to claim 1, characterized in that, The step of controlling the engine start or stop of the dual-motor hybrid system based on the current value of the battery state of charge and the target value of the battery state of charge includes: If the current value of the battery state of charge is less than the target value of the battery state of charge, the engine is controlled to start; If the current value of the battery state of charge is greater than or equal to the target value of the battery state of charge, the engine is controlled to stop.

5. The energy management method for a dual-motor hybrid system according to claim 4, characterized in that, Controlling the engine to start includes: Get the vehicle's current speed; If the current vehicle speed is less than the vehicle speed corresponding to the lowest engine speed in the parallel mode, the engine is controlled to enter the series mode for startup. When the current vehicle speed is greater than or equal to the vehicle speed corresponding to the lowest engine speed in the parallel mode, and the target value of the battery state of charge is greater than the current value of the battery state of charge, the engine is controlled to enter the parallel mode for startup.

6. The energy management method for a dual-motor hybrid system according to claim 5, characterized in that, Controlling the engine to enter series mode for startup includes: Determine the total power requirement of the entire vehicle; Based on the total power demand of the vehicle, the optimal power generation point of the engine in series mode is determined; Based on the optimal power generation point, the target speed and target torque of the engine are determined.

7. The energy management method for a dual-motor hybrid system according to claim 5, characterized in that, Controlling the engine to enter parallel mode for startup includes: Determine the total power requirement of the entire vehicle; The optimal efficiency range of the engine is determined based on the universal characteristic diagram of the engine. Based on the current vehicle speed and the optimal efficiency range, determine the maximum torque at the current vehicle speed; Based on the current vehicle speed and the total power demand of the vehicle, determine the expected torque of the current engine; The target torque of the engine is determined based on the maximum torque and the expected torque.

8. The energy management method for a dual-motor hybrid system according to claim 5, characterized in that, After controlling the engine to start, the method further includes: switching modes within the target road segment; The mode switching within the target road segment includes: Control the engine to maintain its current power; Control the engine torque to reduce to the minimum torque required for mode switching; The allowable charging and discharging power of the motor connected to the engine drive increases from zero to its maximum value; Obtain the current allowable charging and discharging power of the entire vehicle; Based on the vehicle's permissible charging and discharging power and the motor's permissible charging and discharging power, the charging and discharging power during the mode switching process is obtained, wherein the charging and discharging power during the mode switching process is the difference between the vehicle's permissible charging and discharging power and the motor's permissible charging and discharging power.

9. An energy management system for a dual-motor hybrid system, characterized in that, include: The acquisition unit is used to divide the target road segment into n sub-segments based on the navigation information of the target road segment, and acquire the navigation information of each sub-segment, where n is a positive integer; acquire the average vehicle speed of each sub-segment based on the navigation information of each sub-segment; and acquire the expected energy consumption of each sub-segment based on the average vehicle speed of each sub-segment. Based on the expected energy consumption of each of the sub-segments, obtain the estimated battery state of charge for each of the sub-segments. Based on the current battery state of charge (SBC) value and the estimated SBC values ​​for the n road segments, a target SBC value for the target road segment is obtained. Based on the average vehicle speed of each road segment and the expected energy consumption, the energy efficiency level of each road segment is assessed, including low-efficiency, medium-efficiency, medium-high-efficiency, and high-efficiency ranges. For any current road segment, if the energy efficiency level of the current road segment is in the low-efficiency or medium-efficiency range, the target SBC value is determined as the critical value for insufficient battery SBC. If the energy efficiency level of the current road segment is in the medium-high-efficiency or high-efficiency range... In this case, the target value of the battery state of charge is determined as either a first battery state of charge value or a second battery state of charge value. The first battery state of charge value is the sum of the estimated battery state of charge values ​​of the candidate road segments and the current battery state of charge value. The second battery state of charge value is the sum of the additional energy stored in the current road segment and the current battery state of charge value. The candidate road segments are those within the inefficient range and / or the medium-efficiency range of the target road segment. The additional energy stored in the current road segment is the difference between the total energy of the current road segment's maximum efficient range and the expected energy consumption of the current road segment. The control unit is used to control the start or stop of the engine of the dual-motor hybrid system based on the current value of the battery state of charge and the target value of the battery state of charge, wherein the engine start includes series mode start and parallel mode start.

10. A dual-motor hybrid system, characterized in that, The energy management method for a dual-motor hybrid system according to any one of claims 1 to 8, wherein the dual-motor hybrid system comprises: an engine (1), a first motor (2), a second motor (3), a first clutch (4), and a second clutch (5), wherein the output end of the engine (1) is connected to the input end of the first clutch (4), the output end of the first motor (2) is connected to the output end of the first clutch (4) and the input end of the second clutch (5), and the output end of the second motor (3) is connected to the output end of the second clutch (5) and the front axle wheel (6) of the vehicle.

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