Torque limiting method and device and vehicle

Abstract

The invention provides a torque limiting method and device and a vehicle. According to the method, on a low-adhesion road surface, when a vehicle runs at a low speed and a first drive axle is in a gear shifting process or a drive mode is abnormal, the torque demand increasing trend of a driver is monitored in real time, and when the demand torque is increased, the vehicle actively limits the output torque of a drive motor of a second drive axle; therefore, the wheels corresponding to the second drive axle can be prevented from idling due to torque instant overload, the pit digging phenomenon is reduced, and the vehicle sinking risk is remarkably reduced. And meanwhile, by maintaining the power balance of the first drive axle and the second drive axle, the escape capacity and the driving stability are improved, and the optimized balance of the safety and the trafficability of the vehicle under the complex road condition is achieved.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and more particularly, to a method, a device, and a vehicle for limiting torque in the field of vehicle technology. Background Art

[0002] With the continuous advancement of vehicle technology and the improvement of people's living standards, the user base of vehicles is becoming wider and wider. However, with this, there are also more and more vehicle-related problems, including the risk of vehicles getting stuck during driving.

[0003] For four-wheel drive vehicles, when the four-wheel drive vehicle is driving on sand, there is an imbalance in the power distribution between the front and rear drive axles, which may cause the wheels corresponding to the rear drive axle to "dig into holes", resulting in the risk of the vehicle getting stuck.

[0004] Therefore, a method of limiting torque is urgently needed to minimize the "digging" phenomenon of the wheels corresponding to the rear drive axle and reduce the risk of the vehicle getting stuck. Summary of the Invention

[0005] The present application provides a method, device and vehicle for limiting torque, which can minimize the phenomenon of "digging" of the wheels corresponding to the rear drive axle and reduce the risk of the vehicle getting stuck.

[0006] In a first aspect, a method for limiting torque is provided, the method comprising: when a vehicle is traveling on a preset road surface at a speed lower than a speed threshold, detecting whether a first drive axle in the vehicle is in a gear shifting process and / or detecting whether a current driving mode of the vehicle is consistent with a target four-wheel drive mode, the adhesion coefficient of the preset road surface is lower than a preset coefficient, and the driving mode is used to distribute torque to the first drive axle and a second drive axle in the vehicle; when the first drive axle is in a gear shifting process and / or the current driving mode is inconsistent with the target four-wheel drive mode, detecting whether the required torque of the vehicle increases; and when the required torque of the vehicle increases, limiting the output torque of the drive motor of the second drive axle in the vehicle.

[0007] In the above technical solution, on a low-adhesion road surface (a preset road surface with a road adhesion coefficient lower than a preset coefficient), when the vehicle is traveling at a low speed and the first drive axle is in the process of shifting (a brief power interruption) or the drive mode is abnormal (power distribution is unbalanced), the driver's torque demand is monitored in real time. When the required torque increases, the vehicle actively limits the output torque of the drive motor of the second drive axle. This can prevent the wheels corresponding to the second drive axle from idling due to instantaneous torque overload, reduce the occurrence of digging, and thus significantly reduce the risk of the vehicle getting stuck. At the same time, by maintaining the power balance between the first and second drive axles, the ability to escape from difficulties and driving stability are improved, allowing the vehicle to achieve an optimized balance between safety and passability under complex road conditions.

[0008] In combination with the first aspect, in certain possible implementations, the method for determining the speed threshold includes: determining a first speed that matches the driving style of the driver of the vehicle from multiple preset speeds, the first speed being positively correlated with the degree of driving aggressiveness corresponding to the driving style; and adjusting the first speed based on the current driving mode of the vehicle to obtain the speed threshold.

[0009] In this technical solution, the initial speed threshold (first speed) is matched based on the driver's driving style (aggressiveness), ensuring that power response aligns with driving habits. Furthermore, the initial speed threshold is adjusted based on the current driving mode. This prevents excessive power restriction in conservative driving modes, which could affect passability, while also preventing the speed threshold determined by aggressive driving from causing wheelspin. Furthermore, this process takes into account the driver's individual preferences, enhancing the driver's driving experience.

[0010] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the output torque of the drive motor of the second drive axle in the vehicle is limited, including: when the first drive axle is in the gear shifting process, determining the gear shifting progress of the first drive axle when it is in the gear shifting process; based on the gear shifting progress, determining a first amplitude when limiting the output torque of the drive motor of the second drive axle; based on the first amplitude and the first required torque, determining the target torque, and limiting the output torque of the drive motor to not exceed the target torque, the first required torque being the critical torque when the target wheel corresponding to the second drive axle digs a pothole, and the first required torque is related to the preset road surface.

[0011] In this technical solution, the output torque limit for the second drive axle's drive motor is determined based on the real-time shift progress of the first drive axle. This ensures that after power to the first drive axle is interrupted, the torque output of the second drive axle's drive motor precisely matches the shift rhythm. The first required torque is set based on the adhesion characteristics of the pre-set road surface, maximizing power output within a critical safety value. This avoids power waste caused by fixed limits and prevents over-limiting on low-adhesion surfaces, which can cause pitting. It also balances the risk of vehicle entrapment with driving continuity.

[0012] In combination with the first aspect and the above-mentioned implementations, in certain possible implementations, determining the shift progress of the first drive axle when it is in the shifting process includes: determining a first stroke of a shift fork from an initial position to a current position, and determining a first ratio between the first stroke and a total stroke that the shift fork should move, wherein the initial position is the position of the shift fork before the first drive axle is in the shifting process; determining a speed deviation between an actual speed of an input shaft of the first drive axle transmission and a target speed, and determining a deviation amplitude of the speed deviation relative to the target speed, wherein the target speed is the product of an actual speed of an output shaft of the first drive axle transmission and a transmission ratio of the target gear; determining a first coefficient and a second coefficient based on the stage of the first drive axle in the shifting process, wherein the first coefficient is used to measure the degree of influence of the displacement progress of the shift fork on the shifting progress, and the second coefficient is used to measure the degree of influence of the synchronization progress of the input shaft and the output shaft on the shifting progress; and performing a weighted fusion on the first ratio and the deviation amplitude based on the first coefficient and the second coefficient to obtain the shifting progress.

[0013] In this technical solution, the shift fork's displacement progress and the input / output shaft speed deviation (i.e., synchronization progress) are monitored in stages, and weights are dynamically assigned based on the shift phase. This allows for precise quantification of shift progress. Determining the limit range based on this process ensures that the output torque corresponding to the second drive axle is always adapted to the current mechanical state and speed synchronization level during the shift. This prevents slippage caused by premature torque release due to mechanical delays and prevents shock caused by forced engagement when speeds are out of sync.

[0014] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the method for determining the first required torque includes: determining the vertical load of the target wheel based on the total mass of the vehicle, the acceleration of gravity, and the respective proportions of the first drive axle and the second drive axle in torque distribution under the current driving mode; determining the first required torque based on the vertical load, the adhesion coefficient of the preset road surface, and the rolling radius of the target wheel.

[0015] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the target torque is determined based on the first amplitude and the first required torque, including: determining the product of the first required torque and the first amplitude as the first torque; and when the increased required torque is greater than the first torque, determining the first torque as the target torque.

[0016] In this technical solution, the torque limit, determined by the shift progress, is multiplied by the critical torque (first required torque) determined by road adhesion to determine the torque safety limit. If the driver's actual torque demand exceeds the torque safety limit, the torque is forcibly limited to the torque safety limit. This ensures precise adaptation to the current shift stage and road conditions while avoiding excessive power redundancy caused by excessive torque restriction, thus achieving a balance between reducing digging and ensuring power.

[0017] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the output torque of the drive motor of the second drive axle in the vehicle is limited, including: when the current drive mode is inconsistent with the target four-wheel drive mode, based on the first torque distribution ratio of the current drive mode and the second torque distribution ratio of the target four-wheel drive mode, determining the second amplitude when limiting the output torque; based on the second amplitude and the first required torque, determining the target torque, and limiting the output torque of the drive motor to not exceed the target torque.

[0018] In this technical solution, when a drive mode shift is abnormal, the limit amplitude is calculated based on the difference between the current first and second torque distribution ratios, and the target torque is determined by combining the critical torque determined by the road adhesion characteristics. This not only corrects the power distribution imbalance caused by drive mode deviation, but also adjusts the torque limit based on the elasticity of road adhesion to obtain the target torque. This maintains four-wheel drive performance during drive mode shift anomalies, reduces digging, and maximizes traction output, achieving both improved driving safety and system reliability.

[0019] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the first torque distribution ratio is the respective proportions of the first drive axle and the second drive axle when distributing torque in the current drive mode, and the second torque distribution ratio is the respective proportions of the first drive axle and the second drive axle when distributing torque in the target four-wheel drive mode. Based on the first torque distribution ratio of the current drive mode and the second torque distribution ratio of the target four-wheel drive mode, a second amplitude when limiting the output torque is determined, including: based on the first torque distribution ratio and the second torque distribution ratio, determining a first percentage deviation when the second drive axle distributes torque in the current drive mode and the target four-wheel drive mode; multiplying the first percentage deviation by a gain coefficient as a second percentage deviation, the gain coefficient being used to indicate the torque reduction amplitude corresponding to a unit percentage value; and determining the difference between the first percentage value and the second percentage deviation as the second amplitude, the first percentage value being the proportion of the second drive axle when distributing torque in the first torque distribution ratio.

[0020] In this technical solution, the torque distribution ratio is dynamically determined based on the deviation between the current drive mode and the target four-wheel drive mode. This accurately corrects torque distribution errors, preventing overloading the second drive axle and causing spin at the target wheels due to abnormal drive modes. It also flexibly adapts to different scenarios through a gain factor. Simultaneously, the target torque is generated based on the first required torque, maximizing power efficiency within a safe threshold, balancing pothole prevention with traction requirements, and reducing sudden power fluctuations during drive mode switching.

[0021] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the output torque of the drive motor of the second drive axle in the vehicle is limited, including: when the first drive axle is in the gear shifting process and the current drive mode is inconsistent with the target four-wheel drive mode, determining the gear shifting progress of the first drive axle when it is in the gear shifting process; based on the gear shifting progress, determining a first amplitude for limiting the output torque of the drive motor of the second drive axle, and based on the first torque distribution ratio of the current drive mode and the second torque distribution ratio of the target four-wheel drive mode, determining a second amplitude for limiting the output torque; based on the first amplitude, the second amplitude and the first required torque, determining the target torque, and limiting the output torque of the drive motor to not exceed the target torque.

[0022] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the target torque is determined based on the first amplitude, the second amplitude and the first required torque, including: determining the product of the first required torque and the first amplitude as the second torque, and determining the product of the first required torque and the second amplitude as the third torque; and determining the smaller torque between the second torque and the third torque as the target torque.

[0023] In the above technical solution, the limiting amplitude (first amplitude) derived from the shift progress and the limiting amplitude (second amplitude) derived from the drive mode anomaly are respectively multiplied by the first required torque to generate two torque safety thresholds. The smaller value is taken as the final target torque, thus establishing dual safety redundancy. This not only covers the dynamic adaptation of torque during shift power interruption, but also accommodates the distribution ratio correction during drive mode anomalies. Through the barrel effect, the most stringent conditions are always used as the torque limit benchmark, ensuring that the output torque corresponding to the second drive axle does not exceed the adhesion limit under extreme operating conditions. At the same time, it can also avoid safety vulnerabilities caused by the failure of a single limiting factor.

[0024] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, before determining the smaller torque between the second torque and the third torque as the target torque, the method also includes: when the preset road surface is an uphill section, based on the slope of the uphill section, determining a third amplitude for retaining the output torque; determining the product of the first required torque and the third amplitude as the fourth torque; and determining the smaller torque between the second torque and the third torque as the target torque, including: determining the smaller torque between the second torque and the third torque as the fifth torque; determining the larger torque between the fourth torque and the fifth torque as the target torque.

[0025] In this technical solution, on uphill sections, the required torque range is determined based on the slope to generate the anti-rollback torque requirement. The larger of the two limit ranges, derived from shift progress and drive mode anomalies, is then taken as the target torque, prioritizing anti-rollback capability on steep slopes. This prevents the vehicle from slipping backward due to excessive torque restriction. Furthermore, the dual constraints of an upper safety limit and a lower safety limit prevent digging in low-adhesion conditions while ensuring sufficient torque for climbing, achieving a dynamic balance between safety and passability.

[0026] In a second aspect, a device for limiting torque is provided, which includes: a detection module for detecting whether a first drive axle in the vehicle is in a gear shifting process and / or detecting whether a current driving mode of the vehicle is consistent with a target four-wheel drive mode when the vehicle is traveling on a preset road surface at a speed lower than a speed threshold, the adhesion coefficient of the preset road surface is lower than a preset coefficient, and the driving mode is used to distribute torque to the first drive axle and the second drive axle in the vehicle; a determination module for detecting whether the required torque of the vehicle increases when the first drive axle is in a gear shifting process and / or the current driving mode is inconsistent with the target four-wheel drive mode; and a limiting module for limiting the output torque of the drive motor of the second drive axle in the vehicle when the required torque of the vehicle increases.

[0027] In conjunction with the second aspect, in some possible implementations, the determination module is specifically used to: determine a first speed that matches the driving style of the driver of the vehicle from multiple preset speeds, where the first speed is positively correlated with the driving aggressiveness corresponding to the driving style; and adjust the first speed based on the current driving mode of the vehicle to obtain the speed threshold.

[0028] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the determination module is further specifically used to: determine the gear shifting progress of the first drive axle when the first drive axle is in the gear shifting process; based on the gear shifting progress, determine the first amplitude when limiting the output torque of the drive motor of the second drive axle; the limitation module is specifically used to determine the target torque based on the first amplitude and the first required torque, and limit the output torque of the drive motor to not exceed the target torque, the first required torque being the critical torque when the target wheel corresponding to the second drive axle digs a pit, and the first required torque is related to the preset road surface.

[0029] In combination with the second aspect and the above-mentioned implementation manner, in some possible implementation manners, the determination module is further specifically used to: determine a first stroke of the shift fork moving from an initial position to a current position, and determine a first ratio between the first stroke and a total stroke that the shift fork should move, wherein the initial position is the position of the shift fork before the first drive axle is in the shifting process; determine a speed deviation between an actual speed of the input shaft of the first drive axle gearbox and a target speed, and determine a deviation amplitude of the speed deviation relative to the target speed, wherein the target speed is the product of the actual speed of the output shaft of the first drive axle gearbox and the transmission ratio of the target gear; determine a first coefficient and a second coefficient based on the stage of the first drive axle in the shifting process, wherein the first coefficient is used to measure the degree of influence of the displacement progress of the shift fork on the shifting progress, and the second coefficient is used to measure the degree of influence of the synchronization progress of the input shaft and the output shaft on the shifting progress; and perform weighted fusion on the first ratio and the deviation amplitude based on the first coefficient and the second coefficient to obtain the shifting progress.

[0030] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the determination module is further specifically used to: determine the vertical load of the target wheel based on the total mass of the vehicle, the acceleration of gravity, and the respective proportions of the first drive axle and the second drive axle in torque distribution under the current driving mode; and determine the first required torque based on the vertical load, the adhesion coefficient of the preset road surface, and the rolling radius of the target wheel.

[0031] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the determination module is further specifically used to: determine the product of the first required torque and the first amplitude as the first torque; and when the increased required torque is greater than the first torque, determine the first torque as the target torque.

[0032] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the determination module is specifically used to determine the second amplitude for limiting the output torque based on the first torque distribution ratio of the current driving mode and the second torque distribution ratio of the target four-wheel drive mode when the current driving mode is inconsistent with the target four-wheel drive mode; the limitation module is specifically used to determine the target torque based on the second amplitude and the first required torque, and limit the output torque of the drive motor to not exceed the target torque.

[0033] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the first torque distribution ratio is the respective proportions of the first drive axle and the second drive axle when distributing torque in the current drive mode, and the second torque distribution ratio is the respective proportions of the first drive axle and the second drive axle when distributing torque in the target four-wheel drive mode. The determination module is specifically further used to: determine, based on the first torque distribution ratio and the second torque distribution ratio, a first percentage deviation when the second drive axle performs torque distribution in the current drive mode and the target four-wheel drive mode; determine the product of the first percentage deviation and the gain coefficient as the second percentage deviation, and the gain coefficient is used to indicate the torque reduction amplitude corresponding to the unit percentage value; determine the difference between the first percentage value and the second percentage deviation as the second amplitude, and the first percentage value is the proportion of the second drive axle when distributing torque in the first torque distribution ratio.

[0034] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the determination module is further specifically used to: determine the shifting progress of the first drive axle when it is in the shifting process and the current drive mode is inconsistent with the target four-wheel drive mode; determine a first amplitude for limiting the output torque of the drive motor of the second drive axle based on the shifting progress, and determine a second amplitude for limiting the output torque based on the first torque distribution ratio of the current drive mode and the second torque distribution ratio of the target four-wheel drive mode; the limiting module is further specifically used to determine the target torque based on the first amplitude, the second amplitude and the first required torque, and limit the output torque of the drive motor to not exceed the target torque.

[0035] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the determination module is specifically further used to: determine the product of the first required torque and the first amplitude as the second torque, and determine the product of the first required torque and the second amplitude as the third torque; determine the smaller torque between the second torque and the third torque as the target torque.

[0036] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, before determining the smaller torque between the second torque and the third torque as the target torque, the determination module is also used to: when the preset road surface is an uphill section, determine the third amplitude for retaining the output torque based on the slope of the uphill section; determine the product of the first required torque and the third amplitude as the fourth torque; and the determination module is specifically further used to: determine the smaller torque between the second torque and the third torque as the fifth torque; and determine the larger torque between the fourth torque and the fifth torque as the target torque.

[0037] In a third aspect, a vehicle is provided, comprising a memory and a processor. The memory is configured to store executable program code, and the processor is configured to retrieve and execute the executable program code from the memory, so that the vehicle executes the method of the first aspect or any possible implementation of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of a scenario of using a vehicle provided in an embodiment of the present application;

[0039] Figure 2 is a schematic flow chart of a method for limiting torque provided in an embodiment of the present application;

[0040] Figure 3 1 is a schematic structural diagram of a torque limiting device provided in an embodiment of the present application;

[0041] Figure 4 It is a structural schematic diagram of a vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] The following will clearly and thoroughly describe the technical solutions in this application in conjunction with the accompanying drawings. In the description of the embodiments of this application, unless otherwise specified, " / " means or, for example, A / B can mean A or B: "and / or" in the text is only a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more than two.

[0043] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood to imply or suggest relative importance or implicitly indicate the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0044] Figure 1This is a schematic diagram of a vehicle usage scenario provided in an embodiment of the present application.

[0045] For example, Figure 1 As shown, when four-wheel drive vehicle A is driving on a sandy road, it typically shifts gears using the front drive axle after stopping on the sandy road, for example, from parking to reverse. During this process, the front drive axle is in the process of shifting gears, and power transmission is briefly interrupted. If the driver presses the accelerator pedal, four-wheel drive vehicle A can only be driven by the rear drive axle. Because the rear drive axle has to bear more power output and the sandy road surface has insufficient adhesion, the wheels corresponding to the rear drive axle will quickly spin and dig into the sand, putting four-wheel drive vehicle A at risk of getting stuck.

[0046] In order to solve the above problems, an embodiment of the present application proposes a method for limiting torque. By limiting the output torque of the drive motor of the rear drive axle in the above scenario, the phenomenon of "digging holes" of the wheels corresponding to the rear drive axle can be minimized, thereby reducing the risk of the vehicle getting stuck.

[0047] Figure 2 This is a schematic flow chart of a method for limiting torque provided in an embodiment of the present application.

[0048] It should be understood that the method for limiting torque provided in the embodiment of the present application can be applied to Figure 1 The vehicle shown (eg, four-wheel drive vehicle A). Specifically, the method of limiting torque can be applied to a vehicle controller in the vehicle.

[0049] For example, Figure 2 As shown, the method 200 includes the following steps 201 to 203.

[0050] Step 201, when a vehicle is traveling on a preset road surface at a speed lower than a speed threshold, detecting whether a first drive axle in the vehicle is in a gear shifting process and / or detecting whether a current drive mode of the vehicle is consistent with a target four-wheel drive mode, the adhesion coefficient of the preset road surface is lower than a preset coefficient, and the drive mode is used to distribute torque to the first drive axle and a second drive axle in the vehicle.

[0051] It should be understood that the "vehicle" in step 201 is a four-wheel drive vehicle with power output on all four wheels and all four wheels being drive wheels. Optionally, the four-wheel drive vehicle includes any one of a hybrid four-wheel drive vehicle and a fuel four-wheel drive vehicle.

[0052] It should also be understood that "the first drive axle is in the gear shifting process" in the above step 201 refers to the process in which the vehicle is currently switching gears through the gearbox of the first drive axle (ie, the first drive axle gearbox).

[0053] It should also be noted that the “target four-wheel drive mode” in the above step 201 refers to the four-wheel drive mode that the vehicle should use when traveling on a preset road surface.

[0054] Optionally, the preset threshold is 20 km / h.

[0055] Optionally, the preset road surface is a sandy road surface, a wet road surface, or an icy road surface.

[0056] Optionally, the first drive axle is a front drive axle or a rear drive axle in a vehicle.

[0057] Optionally, when the preset road surface is a sandy road surface, the corresponding target four-wheel drive mode is a part-time four-wheel drive mode; when the preset road surface is a wet road surface, the corresponding target four-wheel drive mode is a timely four-wheel drive mode; when the preset road surface is an icy road surface, the corresponding target four-wheel drive mode is a full-time four-wheel drive mode.

[0058] The part-time four-wheel drive mode indicates that the four-wheel drive mode can be manually selected. The timely four-wheel drive mode indicates that the four-wheel drive mode can be automatically switched according to road conditions. The full-time four-wheel drive mode indicates that the vehicle maintains four-wheel drive at all times, with power evenly distributed between the front and rear wheels.

[0059] In one possible implementation, the method for determining the speed threshold in step 201 includes: determining a first speed that matches the driving style of the driver of the vehicle from a plurality of preset speeds, the first speed being positively correlated with the degree of driving aggressiveness corresponding to the driving style; and adjusting the first speed based on the current driving mode of the vehicle to obtain the speed threshold.

[0060] It should be understood that “the first speed is positively correlated with the driving aggressiveness corresponding to the driving style” in the above solution means that the higher the driving aggressiveness, the greater the first speed, and the lower the driving aggressiveness, the lower the first speed.

[0061] In this technical solution, the initial speed threshold (first speed) is matched based on the driver's driving style (aggressiveness), ensuring that power response aligns with driving habits. Furthermore, the initial speed threshold is adjusted based on the current driving mode. This prevents excessive power restriction in conservative driving modes, which could affect passability, while also preventing the speed threshold determined by aggressive driving from causing wheelspin. Furthermore, this process takes into account the driver's individual preferences, enhancing the driver's driving experience.

[0062] In some embodiments, a method for determining a driving aggressiveness corresponding to the driver's driving style includes: determining a first aggressiveness as the driving aggressiveness if the driver's historical driving behavior indicates that the driver's driving acceleration exceeds a preset acceleration by a greater number than a first number, or the driver's driving deceleration exceeds a preset deceleration by a greater number than a first number, or the driver's speed fluctuations with a standard deviation exceeding a preset standard deviation by a greater number than a first number; and determining a second aggressiveness as the driving aggressiveness, the second number being greater than the first number, and the second aggressiveness being higher than the first aggressiveness, if the driver's historical driving behavior indicates that the driver's driving acceleration exceeds a preset acceleration by a greater number than a second number, or the driver's driving deceleration exceeds a preset deceleration by a greater number than a second number, or the driver's speed fluctuations with a standard deviation exceeding a preset standard deviation by a greater number than a second number.

[0063] In other embodiments, the method for determining the degree of driving aggressiveness corresponding to the driver's driving style includes: determining a third degree of driving aggressiveness as the degree of driving aggressiveness when the driver's historical driving behavior indicates that the driver's following distance is greater than a preset distance for a third number of times or the number of violations is greater than a third number of times; and determining a fourth degree of driving aggressiveness as the degree of driving aggressiveness when the driver's historical driving behavior indicates that the driver's following distance is greater than a preset distance for a fourth number of times or the number of violations is greater than a fourth number of times, the fourth number being greater than the third number, and the fourth degree of driving aggressiveness being higher than the third degree of driving aggressiveness.

[0064] Optionally, the violation includes any one of running a red light, crossing a solid line, turning or changing lanes without using a turn signal, and illegally occupying a lane.

[0065] In other embodiments, the method for determining the degree of driving aggressiveness corresponding to the driver's driving style includes: determining the driver's sudden acceleration frequency, sudden deceleration frequency and steering aggressiveness based on the driver's historical driving behavior, the sudden acceleration frequency refers to the ratio of the number of sudden accelerations in which the driving acceleration exceeds a preset acceleration to the number of accelerations, the sudden deceleration frequency refers to the ratio of the number of sudden decelerations in which the driving deceleration exceeds a preset deceleration to the number of decelerations, and the steering aggressiveness refers to the ratio of the number of times the actual steering wheel rotation angle is greater than the required rotation angle to the total number of rotations; based on a third coefficient, a fourth coefficient and a fifth coefficient, weightedly fusing the sudden acceleration frequency, the sudden deceleration frequency and the steering aggressiveness to obtain the driving aggressiveness, the third coefficient is used to indicate the contribution of the sudden acceleration frequency in determining the driving aggressiveness, the fourth coefficient is used to indicate the contribution of the sudden deceleration frequency in determining the driving aggressiveness, and the fifth coefficient is used to indicate the contribution of the steering aggressiveness in determining the driving aggressiveness.

[0066] In some embodiments, based on the current driving mode of the vehicle, the first speed is adjusted to obtain the speed threshold, including: determining a correction coefficient that matches the current driving mode, the correction coefficient is used to correct the first speed according to the driving mode; determining the product of the first speed and the correction coefficient as the second speed; and determining the sum of the second speed and the compensation speed as the speed threshold, the compensation speed is used to correct the first speed according to the road conditions of a preset road surface.

[0067] It should be understood that the compensation speed mentioned above is used to reflect the speed compensation amount for the power distribution requirement of the vehicle due to the road conditions (adhesion coefficient, etc.) of the preset road surface.

[0068] In some embodiments, determining a correction coefficient that matches the current driving mode includes: when the current driving mode is an economy mode, determining a first correction coefficient as the correction coefficient; when the current driving mode is a sport mode, determining a second correction coefficient as the correction coefficient; when the current driving mode is an off-road mode and the preset road surface is an uphill section with a slope greater than a preset slope, determining a third correction coefficient as the correction coefficient; when the current driving mode is an off-road mode and the preset road surface is an uphill section with a slope less than or equal to a preset slope, or when the current driving mode is an off-road mode and the preset road surface is a downhill section, determining a fourth correction coefficient as the correction coefficient, the second correction coefficient being greater than the fourth correction coefficient, the fourth correction coefficient being greater than the first correction coefficient, and the first correction coefficient being greater than the third correction coefficient.

[0069] Optionally, the first correction coefficient is 0.8, the second correction coefficient is 1.2, the third correction coefficient is 0.5, and the fourth correction coefficient is 0.9.

[0070] In some embodiments, the method for determining the compensation speed includes: when the adhesion coefficient of the preset road surface is greater than or equal to the first adhesion coefficient and less than the second adhesion coefficient, determining the first compensation speed as the compensation speed; when the adhesion coefficient of the preset road surface is greater than or equal to the third adhesion coefficient and less than the first adhesion coefficient, determining the second compensation speed as the compensation speed; when the adhesion coefficient of the preset road surface is greater than or equal to the fourth adhesion coefficient and less than the third adhesion coefficient, determining the third compensation speed as the compensation speed; when the adhesion coefficient of the preset road surface is less than the fourth adhesion coefficient, determining the fourth compensation speed as the compensation speed, the first compensation speed is greater than the second compensation speed, the second compensation speed is greater than the third compensation speed, and the third compensation speed is greater than the fourth compensation speed.

[0071] Optionally, the first adhesion coefficient is 0.8, the second adhesion coefficient is 1, the third adhesion coefficient is 0.5, and the fourth adhesion coefficient is 0.2.

[0072] Optionally, the first compensation speed is any speed in [5km / h, 8km / h], the second compensation speed is any speed in [-3km / h, -5km / h], the third compensation speed is any speed in [-10km / h, -15km / h], and the fourth compensation speed is any speed in [-16km / h, -20km / h].

[0073] Exemplarily, the preset road surface is an icy road surface, the adhesion coefficient of the icy road surface is 0.25, the first speed is 55 km / h, the correction coefficient is 0.8, the compensation speed is -14 km / h, and the obtained speed threshold is 30 km / h.

[0074] Step 202 : Detect whether the required torque of the vehicle increases when the first drive axle is in a gear shifting process and / or the current drive mode is inconsistent with the target four-wheel drive mode.

[0075] In some embodiments, detecting whether the required torque of the vehicle increases in step 202 includes detecting whether the driver steps on the accelerator pedal.

[0076] In some embodiments, upon detecting that the driver has depressed the accelerator pedal, it is determined that the required torque of the vehicle has increased.

[0077] Step 203 : When the required torque of the vehicle increases, the output torque of the drive motor of the second drive axle in the vehicle is limited.

[0078] It should be understood that “limiting the output torque of the drive motor of the second drive axle in the vehicle” in the above step 203 means controlling the output torque of the drive motor not to exceed the target torque.

[0079] It should be noted that method 200 describes a process for limiting the output torque of the drive motor of the second drive axle of the vehicle when the vehicle's demand torque increases while the vehicle is traveling at a low speed on a predetermined road surface, the first drive axle is in the process of shifting gears, and / or the vehicle's current drive mode is inconsistent with a target four-wheel drive mode. The conditions for triggering a digging phenomenon at the wheel corresponding to the second drive axle in method 200 are that the vehicle is traveling at a low speed on the predetermined road surface, the first drive axle is in the process of shifting gears, and / or the vehicle's current drive mode is inconsistent with the target four-wheel drive mode, and the increase in the vehicle's demand torque. The "vehicle traveling at a low speed" is due to a conflict in logic between the vehicle traveling at a high speed, the first drive axle being in the process of shifting gears, and / or the current drive mode being inconsistent with the target four-wheel drive mode, which may lead to safety hazards and failure of dynamic stability control (e.g., a conflict between the electronic stability program system and the torque limiting logic). In high-speed scenarios, if these conditions occur, the torque distribution ratio between the first and second drive axles should be dynamically adjusted rather than directly limiting the output torque of the drive motor of the second drive axle. The necessity of increasing the vehicle's demand torque lies in the following: at low speeds, if the demand torque does not increase, the vehicle assumes that the current torque distribution is within a safe threshold, and there is no need to limit the output torque of the second drive axle's drive motor. Furthermore, the condition for the wheels corresponding to the second drive axle to spin requires that the output torque exceeds the resistance provided by the predetermined road surface adhesion. If the demand torque does not increase, the torque received by the second drive axle is insufficient to overcome this resistance, and digging will not occur.

[0080] Furthermore, the conditions for the wheel corresponding to the second drive axle to dig include that the first drive axle is in the process of shifting and / or the current drive mode is inconsistent with the target four-wheel drive mode. The former is due to a temporary interruption of the power transmission corresponding to the first drive axle, resulting in an imbalance in the power distribution between the front and rear drive axles, and the latter is due to the power distribution of the front drive axle not being distributed according to the current distribution, resulting in an incorrect power distribution between the front and rear drive axles.

[0081] It should also be noted that the process of limiting the output torque of the drive motor of the second drive axle is described below using three situations.

[0082] Case 1: only applies to the case where the first drive axle is in the gear shifting process.

[0083] In one possible implementation, limiting the output torque of the drive motor of the second drive axle in the vehicle in step 203 includes: determining a gear shifting progress of the first drive axle when the first drive axle is in the gear shifting process; determining a first amplitude for limiting the output torque of the drive motor of the second drive axle based on the gear shifting progress; determining a target torque based on the first amplitude and a first required torque, and limiting the output torque of the drive motor to not exceed the target torque, the first required torque being a critical torque when a target wheel corresponding to the second drive axle digs a pothole, and the first required torque is related to the preset road surface.

[0084] It should be understood that the "shift progress during the shift process" in the above solution refers to the degree of completion of the first drive axle transmission shifting from the current gear to the target gear. Optionally, the first amplitude can be represented by a percentage or a percentage value.

[0085] It should also be understood that the "first required torque is the critical torque when the target wheel corresponding to the second drive axle digs a pit" in the above scheme means that when the actual output torque of the drive motor of the second drive axle is greater than the first required torque, the target wheel digs a pit, and when the actual output torque is less than or equal to the first required torque, the target wheel theoretically will not dig a pit.

[0086] In this technical solution, the output torque limit for the second drive axle's drive motor is determined based on the real-time shift progress of the first drive axle. This ensures that after power to the first drive axle is interrupted, the torque output of the second drive axle's drive motor precisely matches the shift rhythm. The first required torque is set based on the adhesion characteristics of the pre-set road surface, maximizing power output within a critical safety value. This avoids power waste caused by fixed limits and prevents over-limiting on low-adhesion surfaces, which can cause pitting. It also balances the risk of vehicle entrapment with driving continuity.

[0087] The process of “determining the shift progress when the first drive axle is in the shift process” is described as follows.

[0088] In one possible implementation, determining the shift progress of the first drive axle when the first drive axle is in a shifting process includes: determining a first stroke of a shift fork from an initial position to a current position, and determining a first ratio between the first stroke and a total stroke that the shift fork should move, wherein the initial position is the position of the shift fork before the first drive axle is in the shifting process; determining a speed deviation between an actual speed of an input shaft of the first drive axle transmission and a target speed, and determining a deviation amplitude of the speed deviation relative to the target speed, wherein the target speed is the product of an actual speed of an output shaft of the first drive axle transmission and a transmission ratio of the target gear; determining a first coefficient and a second coefficient based on the stage of the first drive axle in the shifting process, wherein the first coefficient is used to measure the degree of influence of the displacement progress of the shift fork on the shifting process, and the second coefficient is used to measure the degree of influence of the synchronization progress of the input shaft and the output shaft on the shifting process; and performing a weighted fusion of the first ratio and the deviation amplitude based on the first coefficient and the second coefficient to obtain the shifting process.

[0089] It should be understood that the "shift fork" in the above solution is a component of the first drive axle transmission, used to engage and disengage gears in different gears by physically shifting gears or synchronizers. The "first ratio" in the above solution refers to the physical displacement ratio of the shift fork's travel from its initial position to its current position to its total travel. The shift fork's displacement progress reflects the degree of completion of the mechanical action. Optionally, the first ratio and the deviation amplitude can be expressed as percentages or percentage values.

[0090] It should also be understood that the "stage of the first drive axle's shifting process" in the above scheme includes the disengagement phase, the synchronization phase, and the engagement phase. The disengagement phase refers to the shift fork beginning to move and disengage the current gear. The synchronization phase involves the synchronizer adjusting the input shaft speed to match the target speed. The engagement phase involves the shift fork pushing the synchronizer to fully engage the target gear. It should be noted that the sum of the first and second coefficients is 1.

[0091] It should also be noted that when determining the shift progress, it is necessary to evaluate the physical displacement progress of the shift action (i.e., the displacement progress of the shift fork, the degree of completion of the mechanical action) and the matching degree of speed synchronization (i.e., the synchronization progress, the ratio of elimination of the speed difference between the input shaft and the target wheel speed, reflecting the degree of speed synchronization matching). The first coefficient and the second coefficient are then used to balance the impact of the physical displacement progress and the synchronization progress on the overall shift progress. That is, the first ratio and the deviation amplitude are weighted and integrated using the first coefficient and the second coefficient to determine the shift progress.

[0092] In this technical solution, the shift fork's displacement progress and the input / output shaft speed deviation (i.e., synchronization progress) are monitored in stages, and weights are dynamically assigned based on the shift phase. This allows for precise quantification of shift progress. Determining the limit range based on this process ensures that the output torque corresponding to the second drive axle is always adapted to the current mechanical state and speed synchronization level during the shift. This prevents slippage caused by premature torque release due to mechanical delays and prevents shock caused by forced engagement when speeds are out of sync.

[0093] In some embodiments, determining the deviation amplitude of the speed deviation relative to the target speed includes: determining the ratio of the speed deviation to the target speed as a fourth amplitude; and determining the difference between the first preset value and the fourth amplitude as the deviation amplitude.

[0094] It should be understood that the first preset value is 1.

[0095] In some embodiments, the first coefficient and the second coefficient are determined based on the stage in which the first drive axle is in the gear shifting process, including: when the stage is the stage of disengaging from the original gear, the first reference coefficient is determined as the first coefficient, and the second reference coefficient is determined as the second coefficient; when the stage is the synchronization stage, the third reference coefficient is determined as the first coefficient, and the fourth reference coefficient is determined as the second coefficient; when the stage is the engagement stage, the fifth reference coefficient is determined as the first coefficient, and the sixth reference coefficient is determined as the second coefficient, the first reference coefficient is greater than the fifth reference coefficient, the fifth reference coefficient is greater than the third reference coefficient, the fourth reference coefficient is greater than the sixth reference coefficient, and the sixth reference coefficient is greater than the second reference coefficient.

[0096] Optionally, the first reference coefficient is 0.8, the second reference coefficient is 0.2, the third reference coefficient is 0.4, the fourth reference coefficient is 0.6, the fifth reference coefficient is 0.6, and the sixth reference coefficient is 0.4.

[0097] In some embodiments, based on the first coefficient and the second coefficient, the first ratio and the deviation amplitude are weightedly fused to obtain the gear shifting progress, including: determining the product of the first ratio and the first coefficient as the first progress; determining the product of the deviation amplitude and the second coefficient as the second progress; and determining the sum of the first progress and the second progress as the gear shifting progress.

[0098] For example, the target gear is 3rd forward, the shift fork's displacement progress is 60%, the actual speed of the input shaft is 800 rad / s, the actual speed of the output shaft is 600 rad / s, the transmission ratio of 3rd gear is 6:5 (1.2), the first drive axle is in the synchronous phase during the shifting process, and the first coefficient of the synchronous phase is 0.4 and the second coefficient is 0.6. Based on the above known conditions, the target speed is 600 rad / s * 1.2 = 720 rad / s; the speed deviation is |800 rad / s - 720 rad / s| = 80 rad / s; the deviation amplitude is (1 - 80 / 720) * 100% = 88.9%; and the shift progress is 0.4 * 60% + 0.6 * 88.9% = 77.3%.

[0099] The process of “determining a first magnitude of limiting the output torque of the drive motor of the second drive axle based on the gear shift schedule” is described below.

[0100] In some embodiments, determining a first amplitude for limiting the output torque of the drive motor of the second drive axle based on the shift progress includes: determining a difference between the first preset value and the shift progress as the first amplitude.

[0101] In other embodiments, before determining the first amplitude for limiting the output torque of the drive motor of the second drive axle based on the gear shifting progress, the method 200 also includes: determining the gear deviation degree between the current gear and the target gear; and, based on the gear shifting progress, determining the first amplitude for limiting the output torque of the drive motor of the second drive axle, including: determining the first amplitude based on the gear shifting progress and the gear deviation degree.

[0102] It should be understood that the "gear deviation degree" in the above solution can be represented by a percentage or a percentage value.

[0103] In some embodiments, determining the degree of gear deviation between the current gear and the target gear includes: determining the gear deviation between the current gear and the target gear; and normalizing the gear deviation based on the total number of gears of the vehicle to obtain the gear deviation degree.

[0104] It should be understood that the "gear deviation" in the above scheme refers to the difference in the number of gears between the current gear and the target gear, and is represented by an absolute value. Optionally, when the current gear is forward gear 1 and the target gear is forward gear 3, the gear deviation between gear 1 and gear 3 is 2. Optionally, when the current gear is R and the target gear is forward gear 2, the gear deviation between gear R and gear 2 is |R-2|. It should be noted that when either the current gear or the target gear is not represented by a numerical value, the corresponding gear deviation can be specifically determined by the gear numbers corresponding to the current gear and the target gear, respectively.

[0105] For example, the gear number corresponding to the R gear is -1, and the gear number corresponding to the 2 gear is 3, so the gear deviation between the R gear and the 2 gear is 4.

[0106] In some embodiments, the gear deviation is normalized based on the total number of gears of the vehicle to obtain the gear deviation degree, including: determining the ratio between the gear deviation and the total number of gears as the gear deviation degree.

[0107] In some embodiments, the first amplitude is determined based on the gear shift progress and the gear deviation degree, including: determining the larger value of the gear shift progress and the gear deviation degree as the first amplitude; or determining the average value between the gear shift progress and the gear deviation degree as the first amplitude.

[0108] The process of “determining the target torque based on the first amplitude and the first required torque” is described as follows.

[0109] In one possible implementation, the target torque is determined based on the first amplitude and the first required torque, including: determining the product of the first required torque and the first amplitude as the first torque; and determining the first torque as the target torque when the increased required torque is greater than the first torque.

[0110] It should be understood that the "first torque" in the above scheme is the target torque that the output torque of the drive motor of the first drive axle must not exceed, solely due to the influence of the first drive axle shifting. Furthermore, output torque limitation is only necessary when the increased demanded torque exceeds the first torque. When the increased demanded torque is less than or equal to the first torque, the target wheel corresponding to the second drive axle theoretically will not dig, and in this case, output torque limitation is not applied.

[0111] In this technical solution, the torque limit, determined by the shift progress, is multiplied by the critical torque (first required torque) determined by road adhesion to determine the torque safety limit. If the driver's actual torque demand exceeds the torque safety limit, the torque is forcibly limited to the torque safety limit. This ensures precise adaptation to the current shift stage and road conditions while avoiding excessive power redundancy caused by excessive torque restriction, thus achieving a balance between reducing digging and ensuring power.

[0112] In one possible implementation, the method for determining the first required torque includes: determining the vertical load of the target wheel based on the total mass of the vehicle, the acceleration of gravity, and the respective proportions of the first drive axle and the second drive axle in torque distribution under the current driving mode; and determining the first required torque based on the vertical load, the adhesion coefficient of the preset road surface, and the rolling radius of the target wheel.

[0113] It should be understood that the "vertical load of the target wheel" in the above solution refers to the pressure borne by the target wheel in the vertical direction. Optionally, in the current drive mode, the first drive axle and the second drive axle each have a torque distribution ratio of (2:3) or (40%:60%).

[0114] In some embodiments, the vertical load of the target wheel is determined based on the total mass of the vehicle, the acceleration of gravity, and the respective proportions of the first drive axle and the second drive axle in torque distribution under the current driving mode, including: multiplying the second preset value, the total mass, the acceleration of gravity, and the percentage value corresponding to the proportion of the second drive axle in torque distribution under the current driving mode as the vertical load of the target wheel.

[0115] It should be understood that the second preset value is 1 / 2.

[0116] In some embodiments, the first required torque is determined based on the vertical load, the adhesion coefficient of the preset road surface and the rolling radius of the target wheel, including: determining the product of the vertical load, the adhesion coefficient of the preset road surface and the rolling radius as the first required torque.

[0117] Case 2: This only applies to the case where the vehicle's current driving mode is inconsistent with the target four-wheel drive mode.

[0118] In one possible implementation, limiting the output torque of the drive motor of the second drive axle in the vehicle in step 203 includes: determining a second amplitude for limiting the output torque based on a first torque distribution ratio of the current drive mode and a second torque distribution ratio of the target four-wheel drive mode when the current drive mode is inconsistent with the target four-wheel drive mode; determining a target torque based on the second amplitude and the first required torque, and limiting the output torque of the drive motor to not exceed the target torque.

[0119] It should be understood that the "first required torque" in the above solution has the same meaning as the first required torque in Case 1, both being the critical torque when the target wheel corresponding to the second drive axle digs. Optionally, the second amplitude can be represented by a percentage or a percentage value.

[0120] In this technical solution, when a drive mode shift is abnormal, the limit amplitude is calculated based on the difference between the current first and second torque distribution ratios, and the target torque is determined by combining the critical torque determined by the road adhesion characteristics. This not only corrects the power distribution imbalance caused by drive mode deviation, but also adjusts the torque limit based on the elasticity of road adhesion to obtain the target torque. This maintains four-wheel drive performance during drive mode shift anomalies, reduces digging, and maximizes traction output, achieving both improved driving safety and system reliability.

[0121] The process of “determining a second magnitude of limiting the output torque based on the first torque distribution ratio of the current driving mode and the second torque distribution ratio of the target four-wheel driving mode” is described below.

[0122] In one possible implementation, the first torque distribution ratio is the respective proportions of the first drive axle and the second drive axle during torque distribution in the current drive mode, and the second torque distribution ratio is the respective proportions of the first drive axle and the second drive axle during torque distribution in the target four-wheel drive mode. Based on the first torque distribution ratio of the current drive mode and the second torque distribution ratio of the target four-wheel drive mode, a second amplitude for limiting the output torque is determined, including: determining a first percentage deviation when the second drive axle performs torque distribution in the current drive mode and the target four-wheel drive mode based on the first torque distribution ratio and the second torque distribution ratio; determining the product of the first percentage deviation and a gain coefficient as the second percentage deviation, the gain coefficient being used to indicate the torque reduction amplitude corresponding to a unit percentage value; and determining the difference between the first percentage value and the second percentage deviation as the second amplitude, the first percentage value being the proportion of the second drive axle when performing torque distribution in the first torque distribution ratio.

[0123] It should be understood that the "first percentage deviation" in the above scheme is the difference between the second percentage value of the first proportion corresponding to the second drive axle in the first torque distribution ratio and the third percentage value of the second proportion corresponding to the second drive axle in the second torque distribution ratio. The first percentage value, the first percentage deviation and the second percentage deviation are represented by percentages or percentage values.

[0124] Alternatively, the gain factor is 0.5, indicating that the torque is reduced by 0.5% for every 1% deviation.

[0125] In this technical solution, the torque distribution ratio is dynamically determined based on the deviation between the current drive mode and the target four-wheel drive mode. This accurately corrects torque distribution errors, preventing overloading the second drive axle and causing spin at the target wheels due to abnormal drive modes. It also flexibly adapts to different scenarios through a gain factor. Simultaneously, the target torque is generated based on the first required torque, maximizing power efficiency within a safe threshold, balancing pothole prevention with traction requirements, and reducing sudden power fluctuations during drive mode switching.

[0126] In some embodiments, based on the first torque distribution ratio and the second torque distribution ratio, a first percentage deviation when the second drive axle distributes torque in the current driving mode and the target four-wheel drive mode is determined, including: based on the first torque distribution ratio, determining a second percentage value of the first proportion corresponding to the second drive axle in the first torque distribution ratio; based on the second torque distribution ratio, determining a third percentage value of the second proportion corresponding to the second drive axle in the second torque distribution ratio; and determining the absolute value of the difference between the second percentage value and the third percentage value as the first percentage deviation.

[0127] For example, the first torque distribution ratio is (2:3), the second torque distribution ratio is (1:1), and the gain coefficient is 0.5. Converting (2:3) to (40%:60%) and converting (1:1) to (50%:50%), the first percentage value is 40%, the second percentage value is 60%, and the third percentage value is 50%. The first percentage deviation is 60%-50%=10%, the second percentage deviation is 10%*0.5=5%, and the second amplitude is 40%-5%=35%.

[0128] The process of “determining the target torque based on the second amplitude and the first required torque” is described as follows.

[0129] In some embodiments, the target torque is determined based on the second amplitude and the first required torque, including: determining the product of the first required torque and the second amplitude as a sixth torque; and determining the sixth torque as the target torque when the increased required torque is greater than the sixth torque.

[0130] It should be understood that the "sixth torque" in the above scheme is the target torque that limits the output torque of the drive motor of the first drive axle to a maximum of 100% due solely to the inconsistency between the current drive mode and the target four-wheel-drive mode. Furthermore, output torque limitation is only necessary when the increased demanded torque exceeds the sixth torque. When the increased demanded torque is less than or equal to the sixth torque, the target wheel corresponding to the second drive axle theoretically will not dig, and in this case, output torque limitation is not applied.

[0131] Case 3: The first drive axle is in the process of shifting gears and the current driving mode of the vehicle is inconsistent with the target four-wheel drive mode.

[0132] In one possible implementation, limiting the output torque of the drive motor of the second drive axle in the vehicle in step 203 includes: determining the shifting progress of the first drive axle when it is in the shifting process when the first drive axle is in the shifting process and the current drive mode is inconsistent with the target four-wheel drive mode; determining a first amplitude for limiting the output torque of the drive motor of the second drive axle based on the shifting progress, and determining a second amplitude for limiting the output torque based on the first torque distribution ratio of the current drive mode and the second torque distribution ratio of the target four-wheel drive mode; determining a target torque based on the first amplitude, the second amplitude and the first required torque, and limiting the output torque of the drive motor to not exceed the target torque.

[0133] It should be understood that the specific process of "determining the shifting progress when the first drive axle is in the shifting process; and determining the first amplitude for limiting the output torque of the drive motor of the second drive axle based on the shifting progress" in the above scheme is the same as the specific process of "determining the shifting progress when the first drive axle is in the shifting process; and determining the first amplitude for limiting the output torque of the drive motor of the second drive axle based on the shifting progress" in Case 1. The specific process of "determining the second amplitude for limiting the output torque based on the first torque distribution ratio of the current drive mode and the second torque distribution ratio of the target four-wheel drive mode" in the above scheme is the same as the specific process of "determining the second amplitude for limiting the output torque based on the first torque distribution ratio of the current drive mode and the second torque distribution ratio of the target four-wheel drive mode" in Case 2. No further details will be given here.

[0134] It should also be understood that the "first required torque" in the above solution has the same meaning as the first required torque in Case 1, both of which are critical torques when the target wheel corresponding to the second drive axle digs a pit.

[0135] The process of “determining the target torque based on the first amplitude, the second amplitude, and the first required torque” is described as follows.

[0136] In one possible implementation, the target torque is determined based on the first amplitude, the second amplitude and the first required torque, including: determining the product of the first required torque and the first amplitude as the second torque, and determining the product of the first required torque and the second amplitude as the third torque; and determining the smaller torque between the second torque and the third torque as the target torque.

[0137] In the above technical solution, the limiting amplitude (first amplitude) derived from the shift progress and the limiting amplitude (second amplitude) derived from the drive mode anomaly are respectively multiplied by the first required torque to generate two torque safety thresholds. The smaller value is taken as the final target torque, thus establishing dual safety redundancy. This not only covers the dynamic adaptation of torque during shift power interruption, but also accommodates the distribution ratio correction during drive mode anomalies. Through the barrel effect, the most stringent conditions are always used as the torque limit benchmark, ensuring that the output torque corresponding to the second drive axle does not exceed the adhesion limit under extreme operating conditions. At the same time, it can also avoid safety vulnerabilities caused by the failure of a single limiting factor.

[0138] In one possible implementation, before determining the smaller torque between the second torque and the third torque as the target torque, the method 200 also includes: when the preset road surface is an uphill section, determining a third amplitude for retaining the output torque based on the slope of the uphill section; determining the product of the first required torque and the third amplitude as the fourth torque; and determining the smaller torque between the second torque and the third torque as the target torque includes: determining the smaller torque between the second torque and the third torque as the fifth torque; and determining the larger torque between the fourth torque and the fifth torque as the target torque.

[0139] It should be understood that in the above scheme, when the wheel corresponding to the second drive axle triggers the digging phenomenon, the method 200 limits the output torque of the drive motor of the second drive axle while retaining a certain proportion of additional torque to meet the vehicle's uphill needs.

[0140] In this technical solution, on uphill sections, the required torque range is determined based on the slope to generate the anti-rollback torque requirement. The larger of the two limit ranges, derived from shift progress and drive mode anomalies, is then taken as the target torque, prioritizing anti-rollback capability on steep slopes. This prevents the vehicle from slipping backward due to excessive torque restriction. Furthermore, the dual constraints of an upper safety limit and a lower safety limit prevent digging in low-adhesion conditions while ensuring sufficient torque for climbing, achieving a dynamic balance between safety and passability.

[0141] In some embodiments, based on the slope of the uphill section, a third amplitude for retaining the output torque is determined, including: when the slope is less than the first slope, the first reference amplitude is determined as the third amplitude; when the slope is greater than or equal to the first slope and less than the second slope, the second reference amplitude is determined as the third amplitude; when the slope is greater than the second slope, the third reference amplitude is determined as the third amplitude, the third reference amplitude is greater than the second reference amplitude, and the second reference amplitude is greater than the first reference amplitude.

[0142] Optionally, the first slope is 5°, the second slope is 10°, the first reference amplitude is any reference amplitude of [10%, 15%], the first reference amplitude is 20%, and the first reference amplitude is any reference amplitude of [25%, 30%].

[0143] Figure 3 It is a structural schematic diagram of a torque limiting device provided in an embodiment of the present application.

[0144] For example, Figure 3 As shown, the device 300 includes:

[0145] a detection module 301 for detecting, when a vehicle is traveling on a preset road surface at a speed lower than a speed threshold, whether a first drive axle of the vehicle is in a gear shifting process and / or detecting whether a current drive mode of the vehicle is consistent with a target four-wheel drive mode, the adhesion coefficient of the preset road surface being lower than a preset coefficient, and the drive mode being used to distribute torque between the first drive axle and a second drive axle of the vehicle;

[0146] A determination module 302 is configured to detect whether the required torque of the vehicle increases when the first drive axle is in a gear shifting process and / or the current drive mode is inconsistent with the target four-wheel drive mode;

[0147] The limiting module 303 is configured to limit the output torque of the driving motor of the second driving axle in the vehicle when the required torque of the vehicle increases.

[0148] Optionally, the determination module 302 is specifically configured to: determine a first speed that matches the driving style of the driver of the vehicle from a plurality of preset speeds, the first speed being positively correlated with the driving aggressiveness corresponding to the driving style; and adjust the first speed based on the current driving mode of the vehicle to obtain the speed threshold.

[0149] Optionally, the determination module 302 is further specifically used to: determine the gear shifting progress of the first drive axle when the first drive axle is in the gear shifting process; determine a first amplitude for limiting the output torque of the drive motor of the second drive axle based on the gear shifting progress; the limitation module 303 is specifically used to determine the target torque based on the first amplitude and the first required torque, and limit the output torque of the drive motor to not exceed the target torque, the first required torque being the critical torque when the target wheel corresponding to the second drive axle digs a pothole, and the first required torque is related to the preset road surface.

[0150] Optionally, the determination module 302 is further configured to: determine a first stroke of the shift fork from an initial position to a current position, and determine a first ratio between the first stroke and a total stroke that the shift fork should move, wherein the initial position is the position of the shift fork before the first drive axle is in the shifting process; determine a speed deviation between an actual speed of the input shaft of the first drive axle gearbox and a target speed, and determine a deviation amplitude of the speed deviation relative to the target speed, wherein the target speed is the product of an actual speed of the output shaft of the first drive axle gearbox and a transmission ratio of the target gear; determine a first coefficient and a second coefficient based on the stage of the first drive axle in the shifting process, wherein the first coefficient is used to measure the degree of influence of the displacement progress of the shift fork on the shifting progress, and the second coefficient is used to measure the degree of influence of the synchronization progress of the input shaft and the output shaft on the shifting progress; and perform weighted fusion on the first ratio and the deviation amplitude based on the first coefficient and the second coefficient to obtain the shifting progress.

[0151] Optionally, the determination module 302 is further specifically used to: determine the vertical load of the target wheel based on the total mass of the vehicle, the acceleration of gravity, and the respective proportions of the first drive axle and the second drive axle in torque distribution in the current driving mode; and determine the first required torque based on the vertical load, the adhesion coefficient of the preset road surface, and the rolling radius of the target wheel.

[0152] Optionally, the determination module 302 is further configured to: determine the product of the first required torque and the first amplitude as the first torque; and determine the first torque as the target torque when the increased required torque is greater than the first torque.

[0153] Optionally, the determination module 302 is further configured to determine, when the current driving mode is inconsistent with the target four-wheel drive mode, a second amplitude for limiting the output torque based on the first torque distribution ratio of the current driving mode and the second torque distribution ratio of the target four-wheel drive mode; the limitation module 303 is further configured to determine the target torque based on the second amplitude and the first required torque, and to limit the output torque of the drive motor to not exceed the target torque.

[0154] Optionally, the first torque distribution ratio is the respective proportions of the first drive axle and the second drive axle during torque distribution in the current drive mode, and the second torque distribution ratio is the respective proportions of the first drive axle and the second drive axle during torque distribution in the target four-wheel drive mode. The determination module 302 is further specifically used to: determine, based on the first torque distribution ratio and the second torque distribution ratio, a first percentage deviation when the second drive axle performs torque distribution in the current drive mode and the target four-wheel drive mode; determine the product of the first percentage deviation and a gain coefficient as a second percentage deviation, the gain coefficient being used to indicate the torque reduction amplitude corresponding to a unit percentage value; and determine the difference between the first percentage value and the second percentage deviation as the second amplitude, the first percentage value being the proportion of the second drive axle when performing torque distribution in the first torque distribution ratio.

[0155] Optionally, the determination module 302 is further specifically used to: determine the shifting progress of the first drive axle when it is in the shifting process and the current drive mode is inconsistent with the target four-wheel drive mode; determine a first amplitude for limiting the output torque of the drive motor of the second drive axle based on the shifting progress, and determine a second amplitude for limiting the output torque based on the first torque distribution ratio of the current drive mode and the second torque distribution ratio of the target four-wheel drive mode; the limiting module 303 is further specifically used to determine the target torque based on the first amplitude, the second amplitude and the first required torque, and limit the output torque of the drive motor to not exceed the target torque.

[0156] Optionally, the determination module 302 is further specifically used to: determine the product of the first required torque and the first amplitude as the second torque, and determine the product of the first required torque and the second amplitude as the third torque; and determine the smaller torque between the second torque and the third torque as the target torque.

[0157] Optionally, before determining the smaller torque between the second torque and the third torque as the target torque, the determination module 302 is further used to: when the preset road surface is an uphill section, determine the third amplitude for retaining the output torque based on the slope of the uphill section; determine the product of the first required torque and the third amplitude as the fourth torque; and the determination module 302 is specifically further used to: determine the smaller torque between the second torque and the third torque as the fifth torque; and determine the larger torque between the fourth torque and the fifth torque as the target torque.

[0158] Figure 4 It is a structural schematic diagram of a vehicle provided in an embodiment of the present application.

[0159] For example, Figure 4 As shown, the vehicle 400 includes: a memory 401 and a processor 402, wherein the memory 401 stores an executable program code 403, and the processor 402 is used to call and execute the executable program code 403 to perform a method for limiting torque.

[0160] In addition, an embodiment of the present application also protects a device, which may include a memory and a processor, wherein the memory stores executable program code, and the processor is used to call and execute the executable program code to perform a method for limiting torque provided in an embodiment of the present application.

[0161] In this embodiment, the device can be divided into functional modules based on the above-described method examples. For example, each functional module can be mapped to a specific functional module, or two or more functions can be integrated into a single processing module. The integrated module can be implemented in hardware. It should be noted that the module division in this embodiment is illustrative and represents only a logical functional division. In actual implementation, other division methods may be used.

[0162] In the case of dividing each functional module into corresponding functional modules, the device may further include a detection module, a determination module, a restriction module, etc. It should be noted that all relevant contents involved in the above method embodiment can be referred to the functional description of the corresponding functional modules and will not be repeated here.

[0163] It should be understood that the device provided in this embodiment is used to execute the above-mentioned method of limiting torque, and thus can achieve the same effect as the above-mentioned implementation method.

[0164] In the case of an integrated unit, the device may include a processing module and a storage module. When the device is used in a vehicle, the processing module may be used to control and manage the vehicle's movements. The storage module may be used to support the vehicle's execution of relevant executable program code, etc.

[0165] The processing module may be a processor or controller that implements or executes the various exemplary logic blocks, modules, and circuits described in conjunction with the present disclosure. The processor may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a digital signal processing (DSP) and a microprocessor, and the storage module may be a memory.

[0166] In addition, the device provided in the embodiments of the present application can specifically be a chip, component or module, and the chip may include a connected processor and memory; wherein the memory is used to store instructions, and when the processor calls and executes the instructions, the chip can execute a method of limiting torque provided in the above embodiment.

[0167] This embodiment also provides a computer-readable storage medium, which stores executable program code. When the executable program code runs on a computer, the computer executes the above-mentioned related method steps to implement a method for limiting torque provided in the above embodiment.

[0168] This embodiment further provides a computer program product. When the computer program product is run on a computer, it enables the computer to execute the above-mentioned related steps to implement a method for limiting torque provided in the above embodiment.

[0169] Among them, the device, computer-readable storage medium, computer program product or chip provided in this embodiment are all used to execute the corresponding methods provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding methods provided above, and will not be repeated here.

[0170] Through the description of the above implementation methods, technical personnel in the relevant field can understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0171] In the embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of modules or units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0172] The above content is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for limiting torque, characterized in that: The method comprises: detecting, when a vehicle is traveling on a preset road surface at a speed lower than a speed threshold, whether a first drive axle in the vehicle is in a gear shifting process and / or detecting whether a current drive mode of the vehicle is consistent with a target four-wheel drive mode, and an adhesion coefficient of the preset road surface is lower than a preset coefficient, and a drive mode for distributing torque between the first drive axle and a second drive axle in the vehicle; detecting whether the required torque of the vehicle increases when the first drive axle is in a gear shifting process and / or the current drive mode is inconsistent with the target four-wheel drive mode; When the required torque of the vehicle increases, the output torque of the drive motor of the second drive axle in the vehicle is limited.

2. The method according to claim 1, characterized in that The method for determining the speed threshold includes: determining a first speed matching a driving style of a driver of the vehicle from a plurality of preset speeds, the first speed being positively correlated with a driving aggressiveness corresponding to the driving style; The first speed is adjusted based on the current driving mode of the vehicle to obtain the speed threshold.

3. The method according to claim 1, characterized in that The limiting the output torque of the drive motor of the second drive axle in the vehicle includes: When the first drive axle is in a gear shifting process, determining a gear shifting progress of the first drive axle in the gear shifting process; determining a first amplitude for limiting the output torque of the drive motor of the second drive axle based on the gear shift progress; Based on the first amplitude and the first required torque, a target torque is determined, and the output torque of the drive motor is limited to not exceed the target torque. The first required torque is a critical torque when a target wheel corresponding to the second drive axle digs a pothole. The first required torque is related to the preset road surface.

4. The method according to claim 3, characterized in that The determining of the shifting progress of the first drive axle when the first drive axle is in the shifting process includes: determining a first travel distance of a shift fork from an initial position to a current position, and determining a first ratio of the first travel distance to a total travel distance that the shift fork should move, wherein the initial position is a position of the shift fork before the first drive axle is in a shifting process; determining a speed deviation between an actual speed of an input shaft of a first drive axle transmission and a target speed, and determining a deviation magnitude of the speed deviation relative to the target speed, the target speed being the product of the actual speed of an output shaft of the first drive axle transmission and the gear ratio of the target gear; Determining a first coefficient and a second coefficient based on the stage of the first drive axle in the gear shifting process, wherein the first coefficient is used to measure the degree of influence of the displacement progress of the shift fork on the gear shifting progress, and the second coefficient is used to measure the degree of influence of the synchronization progress of the input shaft and the output shaft on the gear shifting progress; Based on the first coefficient and the second coefficient, the first ratio and the deviation amplitude are weightedly integrated to obtain the shift progress.

5. The method according to claim 3, characterized in that The method for determining the first required torque includes: determining a vertical load on the target wheel based on a total mass of the vehicle, gravitational acceleration, and respective proportions of the first drive axle and the second drive axle in torque distribution in the current drive mode; The first required torque is determined based on the vertical load, the adhesion coefficient of the preset road surface, and the rolling radius of the target wheel.

6. The method according to claim 3, characterized in that The determining of the target torque based on the first amplitude and the first required torque includes: determining a first torque by multiplying the first required torque by the first amplitude; When the increased required torque is greater than the first torque, the first torque is determined as the target torque.

7. The method according to claim 1, characterized in that The limiting the output torque of the drive motor of the second drive axle in the vehicle includes: When the current driving mode is inconsistent with the target four-wheel drive mode, determining a second magnitude of limiting the output torque based on a first torque distribution ratio of the current driving mode and a second torque distribution ratio of the target four-wheel drive mode; A target torque is determined based on the second amplitude and the first required torque, and the output torque of the drive motor is limited not to exceed the target torque.

8. The method according to claim 7, characterized in that The first torque distribution ratio is the respective proportions of the first drive axle and the second drive axle during torque distribution in the current drive mode, and the second torque distribution ratio is the respective proportions of the first drive axle and the second drive axle during torque distribution in the target four-wheel drive mode. Determining the second amplitude for limiting the output torque based on the first torque distribution ratio of the current drive mode and the second torque distribution ratio of the target four-wheel drive mode includes: determining, based on the first torque distribution ratio and the second torque distribution ratio, a first percentage deviation when the second drive axle distributes torque in the current drive mode and the target four-wheel drive mode; determining a second percentage deviation by multiplying the first percentage deviation by a gain coefficient, wherein the gain coefficient is used to indicate a torque reduction amplitude corresponding to a unit percentage value; The difference between the first percentage value and the second percentage deviation is determined as the second amplitude, and the first percentage value is the proportion of the second drive axle in the first torque distribution ratio when distributing torque.

9. The method according to claim 1, characterized in that The limiting the output torque of the drive motor of the second drive axle in the vehicle includes: determining a shifting progress of the first drive axle when the first drive axle is in a shifting process and the current drive mode is inconsistent with the target four-wheel drive mode; determining a first magnitude for limiting the output torque of the drive motor of the second drive axle based on the shift progress, and determining a second magnitude for limiting the output torque based on the first torque distribution ratio of the current drive mode and the second torque distribution ratio of the target four-wheel drive mode; A target torque is determined based on the first amplitude, the second amplitude, and a first required torque, and the output torque of the drive motor is limited not to exceed the target torque.

10. The method according to claim 9, characterized in that The determining the target torque based on the first amplitude, the second amplitude, and the first required torque includes: determining a product of the first required torque and the first amplitude as a second torque, and determining a product of the first required torque and the second amplitude as a third torque; The smaller torque between the second torque and the third torque is determined as the target torque.

11. The method according to claim 10, characterized in that Before determining the smaller torque between the second torque and the third torque as the target torque, the method further includes: When the preset road surface is an uphill section, determining a third amplitude for retaining the output torque based on the gradient of the uphill section; multiplying the first required torque and the third amplitude to determine a fourth torque; Furthermore, determining the smaller torque between the second torque and the third torque as the target torque includes: determining the smaller torque between the second torque and the third torque as a fifth torque; The larger torque between the fourth torque and the fifth torque is determined as the target torque.

12. A torque limiting device, characterized in that: The device comprises: a detection module, configured to detect, when the vehicle is traveling on a preset road surface at a speed lower than a speed threshold, whether a first drive axle in the vehicle is in a gear shifting process and / or whether a current driving mode of the vehicle is consistent with a target four-wheel drive mode, the adhesion coefficient of the preset road surface being lower than a preset coefficient, and the driving mode being used to distribute torque between the first drive axle and a second drive axle in the vehicle; a determination module, configured to detect whether the required torque of the vehicle increases when the first drive axle is in a gear shifting process and / or the current drive mode is inconsistent with the target four-wheel drive mode; The limiting module is configured to limit the output torque of the driving motor of the second driving axle in the vehicle when the required torque of the vehicle increases.

13. A vehicle, characterized in that: The vehicle comprises: a memory for storing executable program code; A processor is configured to call and run the executable program code from the memory, so that the vehicle executes the method according to any one of claims 1 to 11.

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