Vehicle braking energy recovery method and system and storage medium
By identifying long downhill driving conditions and calculating speed limits, the regenerative braking of new energy vehicles is controlled, solving the problem of rapid charging of power batteries under long downhill driving conditions, and achieving safe and efficient energy recovery and range improvement.
Patent Information
- Application Number
- CN202511733105.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-24
- Publication Date
- 2026-02-13
AI Technical Summary
New energy vehicles lose braking power during long downhill braking conditions due to the rapid charging of the power battery, resulting in safety hazards and affecting work efficiency, especially for hybrid bulldozers.
By identifying long downhill conditions, the maximum power consumption and gradient are obtained. The speed limit is calculated using a speed limit generation model, and the speed is controlled based on this to reduce the energy recovery power, avoid full-displacement braking of the motor, and ensure braking force and energy recovery efficiency.
Effective management of regenerative braking improves driving range, avoids loss of braking force due to overcharging of the power battery, and ensures driving safety and operational efficiency.
Smart Images
Figure CN121515744A_ABST
Abstract
Description
Technical Field
[0001] This disclosure belongs to the field of vehicle control technology, specifically relating to a method, system, and storage medium for vehicle braking energy recovery. Background Technology
[0002] To improve fuel economy and reduce brake wear, new energy vehicles typically employ a regenerative braking control strategy. This strategy converts the vehicle's kinetic energy into electrical energy via the electric motor when the vehicle is going downhill or decelerating, and then recharges the onboard battery, including the power battery.
[0003] However, the aforementioned control strategies are not suitable for the operational needs of new energy vehicles with only electric braking under long downhill braking conditions. During long downhill braking, the regenerative braking power fully charges the battery. The methods used in related technologies to limit regenerative torque would cause the vehicle to lose braking force, posing a safety hazard. To ensure safety, the vehicle must stop to consume the battery before continuing. This is especially true for hybrid bulldozers, which, due to their greater weight, have a higher regenerative braking power at the same speed during long downhill braking than conventional vehicles. The battery would be rapidly charged, increasing the safety risk, and stopping to consume the battery before continuing would severely impact the operating efficiency of the hybrid bulldozer. Summary of the Invention
[0004] This disclosure provides a method, system, and storage medium for vehicle braking energy recovery, aiming to at least partially solve the technical problem that related technologies do not meet the working requirements of new energy vehicles with only electric braking under long downhill braking conditions.
[0005] At least one embodiment of this disclosure provides a vehicle braking energy recovery method, including: Identify whether the vehicle is in a long downhill driving condition; When the vehicle is in a long downhill condition, obtain the vehicle's current maximum power consumption; Obtain the current slope of the vehicle; The maximum consumable power and the gradient are input into a preset speed limit generation model to obtain a speed limit. The speed limit generation model is configured to generate the speed limit based on the maximum consumable power and the gradient, such that the regenerative power generated by the vehicle is less than the maximum consumable power. The vehicle speed is controlled based on the speed limit, and the vehicle's braking energy is recovered.
[0006] The above solution offers the following technical advantages: It applies dynamics and energy conservation theories to provide a braking energy recovery method suitable for new energy vehicles with only electric braking, particularly hybrid bulldozers. In long downhill driving conditions, to effectively manage the vehicle's braking energy recovery system, the system dynamically adjusts the braking energy control strategy based on the vehicle's current real-time maximum power consumption and the gradient. First, the system calculates the speed limit under the current conditions using the real-time gradient and maximum power consumption (including battery charging power and the power consumption of other vehicle accessories such as air conditioning, DC-DC modules, TMS refrigeration, and PTC heating). Then, based on the calculated speed limit, the system actively adjusts the vehicle's operating state, pre-emptively limiting the vehicle's speed upon entry, thereby reducing the energy recovery power demand during braking. This ensures that the recovered power generated during long downhill braking is always less than the vehicle's total power consumption, preventing the loss of adjustment capability due to full-displacement braking of the electric motor during long downhill driving, and ensuring the system always possesses flexible braking force distribution and energy recovery capabilities. By optimizing braking energy control, vehicles can utilize regenerative braking more efficiently on long downhill sections, significantly improving energy recovery efficiency and extending the vehicle's driving range. Simultaneously, it effectively avoids the problem of insufficient braking energy recovery due to overcharging of the battery, thus preventing the vehicle from becoming unable to operate normally due to insufficient energy management.
[0007] The method provided in at least one embodiment of this disclosure further includes: Construct the speed limit generation model, wherein the speed limit generation model includes: A power-gradient-vehicle speed relationship database, which stores the recovered power corresponding to different combinations of power and gradient, and The query module is configured to traverse the power-gradient-vehicle speed relationship database based on the input maximum consuming power and the gradient, and generate a speed limit that matches the current operating conditions.
[0008] The above solution has the following technical effects: a power-gradient-vehicle speed relationship database for power demand under different working conditions is established in advance. This database can be an offline database. The relationship between gradient, vehicle speed and energy recovery power (also known as energy recovery power) is clearly defined to quickly generate vehicle speed limits.
[0009] The method provided in at least one embodiment of this disclosure further includes: Obtain the correction factor; The speed limit is corrected based on the correction coefficient to generate a corrected speed limit for vehicle speed control. The correction action is used to ensure that the deviation between the regenerative power generated by the vehicle and the maximum expendable power after the vehicle speed is controlled based on the corrected speed limit exceeds a set value.
[0010] The above solution has the following technical advantages: it avoids the regenerative power generated by the vehicle being close to its maximum consumable power. Pre-setting the vehicle speed limit can prevent the motor from losing its adjustable capability during full-displacement braking.
[0011] In at least one embodiment of the method provided in this disclosure, obtaining the correction coefficient includes: Obtain the vehicle's current original speed limit; and, The correction coefficient is generated based on the original speed limit, wherein the correction coefficient changes dynamically with the original speed limit, and the range of the correction coefficient is 0 to 1.
[0012] The above solution has the following technical effects: dynamic adjustment of vehicle speed limit can reduce speed loss during long downhill slopes and maximize vehicle operating efficiency.
[0013] In the method provided in at least one embodiment of this disclosure, the correction coefficient is negatively correlated with the original speed limit.
[0014] The above solution has the following technical advantages: the higher the original speed limit, the smaller the correction coefficient; conversely, the lower the original speed limit, the larger the correction coefficient. Dynamic adjustment of the speed limit can further reduce speed loss during this process, maximizing operational efficiency.
[0015] In at least one embodiment of the method provided in this disclosure, identifying whether a vehicle is in a long downhill condition includes: Obtain the vehicle's current onboard map location data, and based on the onboard map location data, identify that the vehicle is in a long downhill driving condition; or, The gradient of the vehicle at different times within a preset time period is obtained, and the vehicle is identified as being in a long downhill condition when the gradient continuously exceeds the gradient threshold.
[0016] The above solution has the following technical effects: it can flexibly identify long downhill conditions based on whether the vehicle is equipped with a map box and whether the map box is functioning properly.
[0017] In the method provided in at least one embodiment of this disclosure, the maximum power consumption includes at least one of the following: engine friction work, working pump power, fan pump power, air conditioning power, DC-DC converter power, battery charging power, thermal management system power requirements, and range extender reverse drag power.
[0018] The above solution has the following technical effect: it accurately obtains the maximum power consumption based on the vehicle's power-consuming accessories.
[0019] In at least one embodiment of the method provided in this disclosure, the step of controlling the vehicle speed based on the speed limit includes: Upon receiving a braking command, the vehicle's required speed by the driver is obtained; A target vehicle speed is generated based on the speed limit and the driver's desired speed; and... The vehicle is controlled based on the target speed so that the actual speed of the vehicle does not exceed the speed limit.
[0020] The above solution has the following technical effects: it ensures that the vehicle does not exceed the safe speed limit while meeting the driver's driving needs, thereby achieving effective recovery of braking energy under the premise of ensuring driving safety.
[0021] At least one embodiment of this disclosure also provides a vehicle braking energy recovery system, including: The identification unit is configured to identify whether the vehicle is in a long downhill driving condition; The preprocessing unit is configured to obtain the vehicle's current maximum power consumption when the vehicle is in a long downhill condition; The acquisition unit is configured to acquire the current slope of the vehicle; The processing unit is configured to input the maximum consumable power and the gradient into a preset speed limit generation model to obtain a speed limit, wherein the speed limit generation model is configured to generate the speed limit based on the maximum consumable power and the gradient, such that the regenerative power generated by the vehicle is less than the maximum consumable power; and, The control unit is configured to control the vehicle speed based on the speed limit and to control the vehicle to recover braking energy.
[0022] At least one embodiment of this disclosure also provides a storage medium storing a program or instructions, wherein the program or instructions, when executed by a processor, implement the steps of the method provided in any embodiment of this disclosure.
[0023] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description
[0024] To more clearly illustrate the technical solutions in the embodiments of this disclosure, 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 disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0025] Figure 1 A flowchart of a vehicle braking energy recovery method provided for at least one embodiment of this disclosure; Figure 2 A schematic diagram of a long downhill working condition provided for at least one embodiment of this disclosure; Figure 3 A schematic diagram of a speed limit generation model provided for at least one embodiment of this disclosure; Figure 4 A flowchart of a working condition identification scheme provided in at least one embodiment of this disclosure; Figure 5 A flowchart illustrating a vehicle control scheme based on speed limiting, provided for at least one embodiment of this disclosure; Figure 6 Control diagram for a speed limit correction scheme provided in at least one embodiment of this disclosure; Figure 7 Example flowchart of a vehicle braking energy recovery method provided in at least one embodiment of this disclosure; Figure 8 A structural block diagram of a vehicle braking energy recovery system provided in at least one embodiment of this disclosure; Figure 9 A schematic diagram illustrating the composition of a program product provided for at least one embodiment of this disclosure.
[0026] Figure label: 10- Vehicle braking energy recovery system; 11- Identification unit; 12- Preprocessing unit; 13- Acquisition unit; 14- Processing unit; 15- Control unit; 21- Processor; 22- Memory; 23- Input device; 24- Output device; - Slope; - Vehicle speed; -Speed limit; - Vehicle quality; - Gravitational acceleration; - Friction; - Recover power; - Maximum power consumption; - Correction factor, - Revised speed limit. Detailed Implementation
[0027] The present disclosure will now be described in further detail with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are for illustrative purposes only and do not limit the scope of the disclosure. Similarly, the following embodiments are only some, not all, embodiments of the present disclosure, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.
[0028] The terms "first," "second," and "third" used in the embodiments of this disclosure are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first," "second," and "third" may explicitly or implicitly include at least one of that feature.
[0029] In the description of this disclosure, "multiple" means at least two, such as two or three, unless otherwise expressly and specifically limited.
[0030] In this disclosure, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0031] The terms “comprising” and “having”, and any variations thereof, used in this disclosure are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or components inherent to such processes, methods, products, or devices.
[0032] In this disclosure, the term "energy recovery" refers to converting the kinetic energy lost during braking or deceleration in a new energy vehicle (such as an electric vehicle or a hybrid vehicle) into electrical energy and storing that electrical energy back into the vehicle's battery for later use.
[0033] In this disclosure, the term "battery overcharge" refers to the situation where, during the battery charging process, if the charging voltage exceeds its maximum allowable voltage (i.e., overvoltage), or the charging current is too large, or the charging time is too long, abnormal chemical reactions will occur inside the battery, resulting in the generation of gas and heat, and even damage to the battery structure.
[0034] In this disclosure, the term "thermal management system" (TMS) refers to a system used to regulate and manage the temperature of various heat sources inside a vehicle, thereby ensuring that all vehicle components operate in an optimal temperature environment. These heat sources include, but are not limited to, the engine, battery, and electronic devices.
[0035] In the embodiments of this disclosure, the term "DC" refers to direct current.
[0036] In this disclosure, the term "DC-DC converter" refers to an electronic device that converts the voltage value of a DC power supply to another DC voltage value.
[0037] The term "vehicle controller" in this disclosure is abbreviated as VCU.
[0038] The term "engine controller" in this disclosure is abbreviated as ECU.
[0039] The term "renderer controller" in this disclosure is abbreviated as RCU.
[0040] The term "thermal management system" in this disclosure is abbreviated as TMS.
[0041] The term "thermal element" in the embodiments of this disclosure is abbreviated as PTC.
[0042] In this embodiment of the disclosure, the term "long downhill driving condition" refers to a driving condition in which the slope exceeds the set slope and the slope length exceeds the set length. In other words, the vehicle is continuously on a downhill section during driving, which requires the vehicle to use the braking system for a long time to control the vehicle speed in order to avoid excessive acceleration due to gravity.
[0043] Figure 1 A flowchart illustrating a vehicle braking energy recovery method provided in at least one embodiment of this disclosure. This method can be applied to electric vehicles or hybrid vehicles that rely solely on electric braking when going downhill, wherein hybrid vehicles include, but are not limited to, hybrid bulldozers. Figure 1 As shown, the method may include the following steps S10-S50.
[0044] Step S10: Identify whether the vehicle is in a long downhill condition.
[0045] Step S20: When the vehicle is in a long downhill condition, obtain the vehicle's current maximum power consumption.
[0046] Step S30: Obtain the current slope of the vehicle.
[0047] Step S40: Input the maximum consumable power and the gradient into the preset speed limit generation model to obtain the speed limit. The speed limit generation model is configured to generate the speed limit based on the maximum consumable power and the gradient, so that the regenerated power generated by the vehicle is less than the maximum consumable power.
[0048] Step S50: Control the vehicle speed based on the speed limit and control the vehicle to recover braking energy.
[0049] It should be noted that the maximum power dissipation includes the battery's allowed charging power. The purpose of the above speed limit is to allow the vehicle to travel a longer distance on long downhill sections.
[0050] In the above scheme, this disclosure does not limit the long downhill condition identification scheme in step S10. In practical application scenarios, the long downhill condition identification scheme can adopt various methods. For example, the road slope can be obtained in real time by using slope sensors installed on the vehicle, and combined with parameters such as vehicle speed and acceleration, a preset algorithm model can be used to determine whether the current condition is a long downhill condition; alternatively, high-precision map data can be used to obtain the road slope in advance, and when the vehicle travels to the corresponding section, the long downhill condition can be identified by combining the vehicle's real-time status.
[0051] When executing step S10, the system can obtain the road slope through the various methods mentioned above, and accurately determine whether the vehicle is in a long downhill condition based on preset judgment logic and algorithms, so as to be suitable for braking energy recovery. If the judgment result is yes, the system will quickly start the recovery process of steps S20-S50.
[0052] In the above scheme, this disclosure does not limit the method for obtaining the maximum consumable power involved in step S20. In practical application scenarios, the maximum consumable power varies for different vehicles and different operating conditions. The maximum consumable power includes not only the battery's rechargeable power but also factors such as the power consumption of vehicle accessories (e.g., air conditioning, DC-DC module, TMS refrigeration, PTC heating, etc.).
[0053] When executing step S20, the system can comprehensively calculate the maximum power consumption based on the vehicle's current battery status, motor performance, and accessory operation. For example, when the battery charge is low, the system will appropriately reduce the maximum power consumption to protect the battery; while when the motor performance is good and the accessory power consumption is high, the system can allow greater power for energy recovery.
[0054] In the above scheme, this disclosure does not limit the method of obtaining the slope in step S30. In practical application scenarios, vehicles can use sensors installed on the vehicle itself to measure the road slope in real time. These sensors can accurately sense the terrain changes at the vehicle's location and transmit the data to the system in a timely manner. Alternatively, external navigation devices, such as high-precision maps combined with positioning systems, can be used to obtain the current road slope from map data. Or, accurate slope data can be obtained by communicating with traffic infrastructure, such as establishing a connection with a device set up beside the road specifically for transmitting road information such as slope.
[0055] When the system executes step S40, it can obtain a suitable slope acquisition method according to the actual situation and needs. Different acquisition methods have their own advantages and disadvantages.
[0056] In the above scheme, this disclosed system does not limit the speed limit generation model in step S40. The input of the speed limit generation model includes the maximum expendable power and the gradient, and the output of the speed limit generation model includes the speed limit. In practical application scenarios, there are various types of speed limit generation models. For example, the speed limit generation model can be generated based on a physical model. By deeply analyzing the physical characteristics of the vehicle, such as power system parameters and the friction coefficient between the tires and the ground, and combining the maximum expendable power and the gradient, the speed limit can be accurately calculated. For example, the speed limit generation model can also be generated based on historical data. This method collects a large amount of historical vehicle operating data under different operating conditions, including different maximum expendable power, gradients, and corresponding actual safe speeds. Using this data for training, a model that can accurately output the speed limit based on the input maximum expendable power and gradient can be constructed. In addition, the speed limit generation model can also be obtained based on a hybrid generation method that integrates physical models and historical data, taking into account both the physical laws of the vehicle and the advantages of actual data, thereby improving the accuracy and adaptability of the speed limit generation model.
[0057] When the system executes step S40, it inputs the maximum power consumption and gradient into the speed limit generation model to calculate the speed limit, which can quickly obtain the speed limit.
[0058] In the above scheme, this disclosure does not limit the method of vehicle control based on the speed limit in step S50. In practical application scenarios, one feasible approach is to compare the calculated speed limit with the vehicle's current actual speed in real time. When the actual speed exceeds the speed limit, the system automatically triggers braking measures, such as adjusting the engine output power or activating the braking device, to reduce the speed to within the speed limit range. When the actual speed is lower than the speed limit, the system can reasonably adjust the vehicle's driving state according to specific circumstances, such as driving needs and vehicle status, to ensure that the vehicle operates safely and efficiently. Furthermore, vehicle control based on the speed limit can be further optimized by combining vehicle navigation information and road condition information.
[0059] When the system executes step S50, it can select different control methods according to different driving environments and driving requirements.
[0060] Steps S10-S50 effectively achieve vehicle speed control and efficient brake energy recovery under long downhill conditions. Step S10 identifies the vehicle as being on a long downhill slope, and steps S20 and S30 are immediately initiated. The system quickly acquires the vehicle's current maximum expendable power and the gradient, providing crucial data for subsequent speed control. The gradient directly affects the vehicle's downhill speed and brake energy recovery efficiency. Step S40 inputs the acquired maximum expendable power and gradient data into a preset speed limit generation model. This model, rigorously trained and optimized, can quickly and accurately generate speed limits based on the input parameters, ensuring that the vehicle's recovered power remains below the maximum expendable power, thus guaranteeing vehicle safety. The system precisely controls the vehicle's speed based on the calculated speed limit and simultaneously controls brake energy recovery, ensuring both safety during long downhill driving and improving energy efficiency.
[0061] To verify the effectiveness of steps S10-S50, a long downhill braking test was conducted. After setting the gradient and initial vehicle speed, the vehicle's power consumption was collected in real time during the downhill process, including the battery, thermal management system, DC-DC converter, power pump, fan pump, and other accessories. During the downhill process, it was observed that the vehicle speed was limited after the available battery charging power decreased to a certain value, and that the vehicle speed was limited after a certain period of downhill driving. This speed limit ensured that the regenerative power generated by the vehicle was always lower than the actual power consumed by the vehicle.
[0062] The control principles involved in the above methods are introduced below.
[0063] Long downhill working conditions such as Figure 2 As shown, based on dynamic theory, the regenerative power generated by the vehicle can be obtained. With slope Speed The relationship between them is:
[0064] In the formula, Indicates vehicle mass. Represents gravitational acceleration. Represents friction. This represents the conversion factor.
[0065] Vehicle quality Given parameters. Conversion factor. The overall system efficiency, ranging from 0 to 1, can be determined experimentally, with different conversion factors corresponding to different motors. Different. Different vehicle speeds are preset. and slope Regarding vehicle speed and slope After performing arithmetic progression, different vehicle speeds can be obtained using the above formula. and slope Regenerative power generated by the vehicle under combined conditions .
[0066] Based on this, a speed limit generation model can be established, such as... Figure 3 As shown. This speed limit generation model includes, but is not limited to, an offline power-gradient-speed relationship database and query module. This database can be an offline database.
[0067] Based on the law of conservation of energy, during the braking process, the kinetic energy of a vehicle is converted into consumable energy through the braking device. Part of this energy is used for the consumption of vehicle accessories, and the other part is used for battery storage.
[0068] When the system determines that it is a long downhill condition and there is a braking requirement, it immediately performs braking energy control based on the overall vehicle status. Specifically, it uses the calculated maximum power consumption and gradient to call the speed limit generation model online to look up the speed limit. Based on the maximum power consumption and gradient, it selects the speed limit that matches the current condition to prevent the vehicle from losing braking force on a long downhill.
[0069] Some embodiments of this disclosure also provide systems, storage media, and program products corresponding to the methods described above.
[0070] The method provided by at least one embodiment of this disclosure is applicable to any existing vehicle application scenario involving only electric braking on downhill slopes. For example, in the field of new energy vehicles, whether electric or hybrid, this method can function precisely when the vehicle is traveling downhill and relying solely on electric braking. By efficiently controlling the permanent magnet synchronous motor, it achieves reasonable energy recovery and utilization, improving the vehicle's range while enhancing its stability and safety during downhill driving. In industrial driving scenarios, for some large electric transport equipment, especially hybrid bulldozers, when only electric braking is used during downhill sections, this method can also extract braking energy for control before overcharging, preventing the vehicle from losing braking power on long downhill sections.
[0071] Figure 4 A flowchart illustrating a working condition identification scheme provided in at least one embodiment of this disclosure. Figure 1 Based on this, in order to accurately identify long downhill working conditions, such as Figure 4 As shown, step S10 is further refined to include the following sub-steps S101 or S102.
[0072] Sub-step S101: Obtain the vehicle's current onboard map location data, and identify the vehicle as being in a long downhill condition based on the onboard map location data.
[0073] Sub-step S102: Obtain the slope of the vehicle at different times within a preset time period, and identify the vehicle as being in a long downhill condition when the slope continuously exceeds the slope threshold.
[0074] It should be noted that sub-step S101 and sub-step S102 do not necessarily exist simultaneously. Step S10 may contain only sub-step S101 or only sub-step S102.
[0075] If the vehicle is equipped with a map box and the map box is functioning properly, it can obtain onboard map location data, including the gradient of the road ahead and the length of the downhill section, to determine whether it is a long downhill driving condition. If the vehicle is not equipped with a map box or the map box is malfunctioning, it can obtain the gradient feedback from the gradient sensor. If the gradient is downhill and remains so for a preset time (this preset time can be calibrated as needed), it is considered a long downhill driving condition.
[0076] In some embodiments, Figure 1Based on this, to accurately obtain the maximum consumable power, step S20 includes, but is not limited to, the vehicle's engine friction work, working pump power, fan pump power, air conditioning power, DC-DC converter power, battery allowable charging power, thermal management system required power, and range extender reverse drag power. Among these, engine friction work is the power consumed by the frictional resistance generated during the relative movement of internal engine parts, significantly impacting the calculation of maximum consumable power; working pump power is the power required for the operation of various working pumps in the vehicle, and its power varies depending on the operating state of different pumps; fan pump power is the power consumed during fan pump operation, related to the vehicle's cooling needs; air conditioning power depends on factors such as the air conditioning's operating mode and set temperature; DC-DC converter power is used to convert between different voltages, and its magnitude affects the vehicle's energy distribution; battery allowable charging power reflects the upper limit of charging power the battery can accept under current conditions; thermal management system required power is the power consumed to maintain the appropriate operating temperature of various vehicle components; and range extender reverse drag power is the power consumed by the reverse drag effect generated by the range extender under specific operating conditions. These power factors work together to determine the vehicle's maximum consumable power.
[0077] It should be noted that there are two ways to obtain engine friction work. One way is to look up the engine speed in a table. The input is the engine speed and the output is the engine friction work. The friction work corresponding to different speeds is obtained through bench tests. The engine friction work is different for different engine models.
[0078] As an example, engine friction work, working pump power, and fan pump power can be obtained by referring to relevant tables based on the engine feedback speed. Range extender reverse drag power, battery allowable charging power, and thermal management system required power can be obtained through message feedback from each controller; air conditioning power and DC-DC converter power can be calibrated to fixed values.
[0079] The vehicle control method is as follows: the engine controller (ECU) sends messages to the vehicle controller (VCU) in real time; the range extender reverse drag power is sent to the vehicle controller (VCU) in real time by the range extender controller (RCU) via messages; the thermal management system (TMS) power requirement is sent to the vehicle controller (VCU) in real time by the thermal management system controller via messages.
[0080] In some embodiments, Figure 1Building upon this foundation, to generate a speed limit matching the current actual operating conditions in the shortest possible time, step S40, the speed limit generation model, may include a power-gradient-speed relationship database and a query module. The power-gradient-speed relationship database stores the regenerative power corresponding to different power and gradient combinations. The query module is configured to traverse the power-gradient-speed relationship database based on the input maximum consumable power and gradient, and generate a speed limit matching the current operating conditions. The power-gradient-speed relationship database is constructed through extensive experimental data and theoretical calculations, covering regenerative power under various common power and gradient combinations, providing a solid data foundation for accurately generating speed limits. The query module employs an efficient algorithm that can quickly and accurately traverse the database based on the input maximum consumable power and gradient, generating a speed limit matching the current actual operating conditions in the shortest possible time, thereby effectively ensuring the stability and safety of the vehicle's regenerative braking process.
[0081] Figure 5 A flowchart illustrating a vehicle control scheme based on speed limiting, provided for at least one embodiment of this disclosure. Figure 5 Based on this, in order to ensure that the power generated by the vehicle is less than the maximum power that can be consumed, such as Figure 5 As shown, step S50 is further refined into sub-steps S501-503.
[0082] Sub-step S501: After receiving the braking command, obtain the vehicle speed required by the driver.
[0083] Sub-step S502: Generate the target vehicle speed based on the speed limit and the driver's required speed.
[0084] Sub-step S503: Control the vehicle based on the target vehicle speed so that the actual vehicle speed does not exceed the speed limit.
[0085] When a long downhill slope is identified and a braking request is requested, braking energy control is immediately initiated based on the vehicle's overall condition. The determination of braking energy requires comprehensive consideration of the downhill gradient and the vehicle's maximum power consumption. Based on the maximum power consumption calculated in step S20 and the gradient calculated in step S30, an offline database is accessed online to perform a reverse lookup of the speed limit. During this reverse lookup, the maximum power consumption is selected to match the power-gradient-speed relationship for the current operating condition. After determining the speed limit, it is used as a constraint on the target speed. If the driver's desired speed is higher than the speed limit, the target speed is generated based on the speed limit; if the driver's desired speed is lower than the speed limit, the driver's desired speed is used as the target speed. Simultaneously, throughout the entire braking energy recovery process, the vehicle's actual speed is continuously monitored. When the actual speed approaches the speed limit, the control strategy is adjusted promptly to ensure the vehicle always travels within a safe speed range, further improving the efficiency of braking energy recovery and vehicle safety.
[0086] In some embodiments, Figure 1 , Figure 4 or Figure 5 In order to determine the speed limit more efficiently and accurately, the method further includes the following step S01.
[0087] Step S01: Construct a speed limit generation model, which includes a power-gradient-speed relationship database and a query module.
[0088] The power-gradient-speed database stores safe speed limits under different power and gradient conditions. This data, derived through extensive experiments and simulations, accurately reflects the safe speed range of vehicles under various operating conditions. The query module, based on real-time vehicle power and gradient information, quickly retrieves data from the power-gradient-speed database to determine the speed limit under the current operating condition. By constructing such a speed limit generation model, speed limits can be determined more efficiently and accurately, providing a reliable basis for subsequent target speed generation.
[0089] In some embodiments, Figure 1 , Figure 4 or Figure 5 In order to ensure the braking control effect, the method further includes the following steps S41-S42.
[0090] Step S41: Obtain the correction coefficient.
[0091] Step S42: Correct the speed limit based on the correction coefficient to generate the corrected speed limit for vehicle speed control.
[0092] Steps S41-S42 can be placed between steps S40 and S50. The correction coefficient can be a fixed value or dynamically adjusted. The above correction is used to ensure that the deviation between the regenerative power and the maximum expendable power generated by the vehicle after speed control based on the corrected speed limit exceeds a set value. To ensure braking control effectiveness and avoid the situation where the regenerative power is still close to the maximum expendable power after speed limit, the speed limit generated by the speed limit generation model needs to be multiplied by the correction coefficient to ensure that the regenerative power is less than the maximum expendable power. The correction coefficient can be a fixed value across the entire speed range or can be dynamically adjusted according to the magnitude of the matched speed. The corrected speed will be determined as the final speed limit, and the smaller of the speed limit and the speed required by the driver will be used as the target speed output.
[0093] In some embodiments, in order to achieve more efficient energy utilization, step S41 is refined to include sub-steps S411-S412.
[0094] Sub-step S411: Obtain the vehicle's current original speed limit.
[0095] Sub-step S412: Generate a correction coefficient based on the original speed limit, wherein the correction coefficient changes dynamically with the original speed limit and the range of the correction coefficient is 0~1.
[0096] In sub-step S411, the initial vehicle speed limit can be obtained based on power-gradient-vehicle speed relationship data to match the current operating conditions, or it can be the x-axis data in the correction coefficient MAP. This data will serve as a crucial basis for generating the correction coefficient in sub-step S412. By dynamically adjusting the correction coefficient, the power deviation during vehicle braking energy recovery can be controlled more precisely, ensuring that the recovered power is always less than the maximum power consumed, thereby improving braking control effectiveness. In practical applications, this dynamic adjustment method can flexibly adapt to the energy recovery requirements at different vehicle speeds, thus achieving more efficient energy utilization.
[0097] In the above scheme, the relationship between the correction coefficient and the original speed limit can be pre-calibrated. During actual operation, the system only needs to call the pre-calibrated correction coefficient based on the acquired original speed limit, eliminating the need for complex calculations. This significantly improves the system's response speed and operating efficiency. Furthermore, pre-calibrating the relationship between the correction coefficient and the original speed limit ensures the accuracy and stability of the correction coefficient under different operating conditions, further enhancing the reliability and effectiveness of vehicle regenerative braking.
[0098] Figure 6 A control diagram for a speed limit correction scheme provided in at least one embodiment of this disclosure. (See diagram below.) Figure 6 As shown, based on slope and vehicle speed Generate speed limit Based on speed limit and correction factor Generate the corrected speed limit The revised speed limit more accurately reflects the appropriate speed limit for the vehicle under current complex operating conditions, providing a more accurate speed basis for subsequent power control and other operations during vehicle regenerative braking, and helping to further improve the efficiency and reliability of vehicle regenerative braking.
[0099] In some embodiments, to ensure optimal energy utilization at different vehicle speeds, the correction factor is negatively correlated with the original speed limit. The specific value of the correction factor can be calibrated experimentally, ensuring that the recovered power after speed limiting is not close to the maximum power consumed. The calibration principle is to apply a larger correction at high speeds and a smaller correction at low speeds. This means that when the original speed limit is high, the correction factor will be relatively small, limiting excessive increases in recovered power and preventing exceeding the vehicle's maximum power consumption; while when the original speed limit is low, the correction factor will be relatively large to fully utilize the energy recovered during braking. This negatively correlated adjustment mechanism further optimizes the efficiency of regenerative braking, ensuring optimal energy utilization at different vehicle speeds.
[0100] Figure 7 An example flowchart of a vehicle braking energy recovery method provided in at least one embodiment of this disclosure. Figure 7 As shown, under long downhill braking conditions, braking energy control is performed based on the overall vehicle status (vehicle speed, vehicle posture, and working scenario). The speed limit is determined by comprehensively considering factors such as slope, power consumption of accessories, and rechargeable power of the power battery. By limiting the vehicle speed, the purpose of reducing regenerative braking power is achieved, enabling the vehicle to travel a longer distance under long downhill braking conditions and preventing the vehicle from losing braking power due to overcharging of the power battery, which could lead to the vehicle becoming unable to drive.
[0101] Figure 8 This is a structural block diagram of a vehicle braking energy recovery system provided in at least one embodiment of the present disclosure. This vehicle braking energy recovery system is applied to vehicles that rely solely on electric braking during long downhill driving conditions. Figure 8 As shown, the vehicle braking energy recovery system 10 includes an identification unit 11, a preprocessing unit 12, an acquisition unit 13, a processing unit 14, and a control unit 15.
[0102] The identification unit 11 is configured to identify whether the vehicle is in a long downhill condition.
[0103] The preprocessing unit 12 is configured to obtain the vehicle's current maximum power consumption when the vehicle is in a long downhill condition.
[0104] Acquisition unit 13 is configured to acquire the current slope of the vehicle.
[0105] The processing unit 14 is configured to input the maximum consumable power and the gradient into a preset speed limit generation model to obtain the speed limit. The speed limit generation model is configured to generate the speed limit based on the maximum consumable power and the gradient, so that the regenerated power generated by the vehicle is less than the maximum consumable power.
[0106] The control unit 15 is configured to control the vehicle speed based on a speed limit and to control the vehicle to recover braking energy.
[0107] The specific execution methods of each unit in the above system embodiments have been described in detail in the embodiments related to the method, and will not be elaborated here.
[0108] In some embodiments, Figure 8 Based on this, the acquisition unit 13 can be implemented through a corresponding sensor, and the identification unit 11, preprocessing unit 12, processing unit 14 and control unit 15 can be implemented through a controller or control module with corresponding programs.
[0109] This disclosure also provides a storage medium storing a program or instructions that, when executed by a processor, implement the steps of the method embodiments described above.
[0110] This disclosure also provides a program product, such as... Figure 9 As shown, the program product includes one or more processors 21 and memory 22. Figure 9 Take a processor 21 as an example.
[0111] The controller may also include an input device 23 and an output device 24.
[0112] The processor 21, memory 22, input device 23, and output device 24 can be connected via a bus or other means. Figure 9 Taking the example of a connection between China and Israel via a bus.
[0113] The processor 21 can be a central processing unit (CPU), or it can be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or combinations of the above types of chips. The general-purpose processor can be a microprocessor or any conventional processor.
[0114] The memory 22, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as the program instructions / modules corresponding to the methods in the embodiments of this disclosure. The processor 21 executes various functional applications and data processing of the server by running the non-transitory software programs, instructions, and modules stored in the memory 22, thereby implementing the steps of the above-described method embodiments.
[0115] The memory 22 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created by the use of the processing device operated by the server. Furthermore, the memory 22 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 22 may optionally include memory remotely located relative to the processor 21, and these remote memories may be connected to a network connection device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.
[0116] Input device 23 can receive input digital or character information, and generate key signal inputs related to driver settings and function control of the server's processing unit. Output device 24 may include display devices such as a display screen.
[0117] One or more modules are stored in memory 22, and when executed by one or more processors 21, they perform actions such as... Figure 1 The method shown.
[0118] Those skilled in the art will understand that all or part of the processes in the above method embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes described in the above method embodiments. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), random access memory (RAM), flash memory (FM), hard disk drive (HDD), or solid-state drive (SSD), etc.; the storage medium can also include combinations of the above types of memory.
[0119] Although embodiments of the present disclosure have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present disclosure, and such modifications and variations all fall within the scope defined by the appended claims.
[0120] Although embodiments of the present disclosure have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present disclosure.
Claims
1. A method for recovering braking energy in a vehicle, characterized in that, include: Identify whether the vehicle is in a long downhill driving condition; When the vehicle is in a long downhill condition, obtain the vehicle's current maximum power consumption; Obtain the current slope of the vehicle; The maximum consumable power and the gradient are input into a preset speed limit generation model to obtain a speed limit. The speed limit generation model is configured to generate the speed limit based on the maximum consumable power and the gradient, such that the regenerative power generated by the vehicle is less than the maximum consumable power. The vehicle speed is controlled based on the speed limit, and the vehicle's braking energy is recovered.
2. The method according to claim 1, characterized in that, Also includes: Construct the speed limit generation model, wherein the speed limit generation model includes: A power-gradient-vehicle speed relationship database, which stores the recovered power corresponding to different combinations of power and gradient, and The query module is configured to traverse the power-gradient-vehicle speed relationship database based on the input maximum consuming power and the gradient, and generate a speed limit that matches the current operating conditions.
3. The method according to claim 1 or 2, characterized in that, Also includes: Obtain the correction factor; as well as, The speed limit is corrected based on the correction coefficient to generate a corrected speed limit for vehicle speed control. The correction action is used to ensure that the deviation between the regenerative power generated by the vehicle and the maximum expendable power after the vehicle speed is controlled based on the corrected speed limit exceeds a set value.
4. The method according to claim 3, characterized in that, The process of obtaining the correction coefficient includes: Obtain the vehicle's current original speed limit; and, The correction coefficient is generated based on the original speed limit, wherein the correction coefficient changes dynamically with the original speed limit, and the range of the correction coefficient is 0 to 1.
5. The method according to claim 4, characterized in that, The correction factor is negatively correlated with the original speed limit.
6. The method according to claim 1 or 2, characterized in that, The method of identifying whether a vehicle is in a long downhill driving condition includes: Obtain the vehicle's current onboard map location data, and based on the onboard map location data, identify that the vehicle is in a long downhill driving condition; or, The gradient of the vehicle at different times within a preset time period is obtained, and the vehicle is identified as being in a long downhill condition when the gradient continuously exceeds the gradient threshold.
7. The method according to claim 1 or 2, characterized in that, The maximum power consumption includes at least one of the following: engine friction work, working pump power, fan pump power, air conditioning power, DC-DC converter power, battery charging power, thermal management system power requirements, and range extender reverse drag power.
8. The method according to claim 1 or 2, characterized in that, The method of controlling the vehicle speed based on the speed limit includes: Upon receiving a braking command, the vehicle's required speed by the driver is obtained; A target vehicle speed is generated based on the speed limit and the driver's desired speed; and... The vehicle is controlled based on the target speed so that the actual speed of the vehicle does not exceed the speed limit.
9. A vehicle braking energy recovery system, characterized in that, include: The identification unit is configured to identify whether the vehicle is in a long downhill driving condition; The preprocessing unit is configured to obtain the vehicle's current maximum power consumption when the vehicle is in a long downhill condition; The acquisition unit is configured to acquire the current slope of the vehicle; The processing unit is configured to input the maximum consumable power and the slope into a preset speed limit generation model to obtain a speed limit, wherein the speed limit generation model is configured to generate the speed limit based on the maximum consumable power and the slope, so that the regenerative power generated by the vehicle is less than the maximum consumable power. as well as, The control unit is configured to control the vehicle speed based on the speed limit and to control the vehicle to recover braking energy.
10. A storage medium, characterized in that, The storage medium stores a program or instructions, wherein the program or instructions, when executed by a processor, implement the steps of the method as described in any one of claims 1 to 8.