Torque control method, device, equipment and storage medium for four-wheel drive vehicle

Abstract

This application discloses a torque control method, device, equipment, and storage medium for a four-wheel drive vehicle, relating to the field of vehicle technology. The torque control method for the four-wheel drive vehicle includes: upon receiving a drive mode switching command, determining a torque distribution ratio threshold based on current vehicle operating parameters and a distribution ratio mapping relationship; determining a target torque distribution ratio based on the current torque distribution ratio and the torque distribution ratio threshold; and controlling the torque of the four-wheel drive vehicle based on the target torque distribution ratio. By processing the distribution ratio during the switch from two-wheel drive to four-wheel drive, and ensuring that the torque loss due to the torque increment on the new drive shaft during the restricted process is compensated by the other drive shaft, torque filtering is achieved for the condition of gear grinding between the motor gear and the shaft end gear, thereby avoiding gear grinding.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, and in particular to torque control methods, devices, equipment and storage media for four-wheel drive vehicles. Background Technology

[0002] Currently, to further improve the power and driving experience of new energy vehicles, an increasing number of new energy vehicles are adopting a four-wheel drive configuration with dual front and rear motors. In some four-wheel drive distribution strategies that prioritize optimal energy consumption, the vehicle is not required to use four-wheel drive throughout the entire driving process. To optimize economy, rear-wheel drive is used at low speeds, and four-wheel drive is activated as the speed increases. During this process, the backlash between the transmission gears connecting the motors can cause gear grinding due to rapid impacts. It's worth noting that currently, people often only notice gear grinding caused by the motor torque crossing to zero during vehicle startup or by a sudden change in torque direction during energy recovery. Both of these situations are due to the torque crossing to zero.

[0003] When switching from rear-wheel drive to four-wheel drive in a four-wheel drive vehicle, the front wheels change from driven wheels to driving wheels. If torque control is not properly managed, gear grinding can easily occur. However, front axle gear grinding is not solely caused by torque crossing zero; the causes are more complex. Gear grinding can occur even when torque has crossed zero, not at the point of zero torque. Therefore, completely avoiding gear grinding when switching from two-wheel drive to four-wheel drive has become a pressing issue. Summary of the Invention

[0004] The main objective of this application is to provide a torque control method, device, equipment, and storage medium for a four-wheel drive vehicle, aiming to solve the technical problem of how to completely avoid gear grinding when switching from two-wheel drive mode to four-wheel drive mode.

[0005] To achieve the above objectives, this application proposes a torque control method for a four-wheel drive vehicle, the torque control method for the four-wheel drive vehicle comprising:

[0006] Upon receiving a drive mode switching command, the torque distribution ratio threshold is determined based on the current vehicle operating parameters and the distribution ratio mapping relationship;

[0007] The target torque distribution ratio is determined based on the current torque distribution ratio and the torque distribution ratio threshold.

[0008] The torque of the four-wheel drive vehicle is controlled according to the target torque distribution ratio.

[0009] In one embodiment, the step of determining the target torque distribution ratio based on the current torque distribution ratio and the torque distribution ratio threshold includes:

[0010] The current torque distribution ratio is compared with the torque distribution ratio threshold to obtain the target comparison result;

[0011] When the target comparison result is that the current torque distribution ratio is greater than or equal to the torque distribution ratio threshold, the current torque distribution ratio is subjected to limit processing to obtain the limit distribution ratio;

[0012] The target torque distribution ratio is determined based on at least one of the limit distribution ratio, the first gradient limit, and the second gradient limit, wherein the second gradient limit is greater than the first gradient limit.

[0013] In one embodiment, the step of determining the target torque distribution ratio based on at least one of the limit distribution ratio, the first gradient limit, and the second gradient limit includes:

[0014] The target allocation ratio difference is obtained by calculating the difference between the limit allocation ratio and the adjacent allocation ratio.

[0015] The target allocation ratio difference is compared with the first gradient limit and the second gradient limit respectively to obtain the allocation ratio difference comparison result;

[0016] The target allocation ratio is determined based on at least one of the following: the allocation ratio difference comparison result, the adjacent allocation ratio, the limit allocation ratio, the first gradient limit, and the second gradient limit.

[0017] In one embodiment, the step of determining the target allocation ratio based on at least one of the allocation ratio difference comparison result, the adjacent allocation ratio, the limit allocation ratio, the first gradient limit, and the second gradient limit includes:

[0018] When the target allocation ratio difference is less than the first gradient limit, the target allocation ratio is determined based on the limit allocation ratio and the first gradient limit.

[0019] When the target allocation ratio difference is greater than the second gradient limit, the target allocation ratio is determined based on the limit allocation ratio and the second gradient limit.

[0020] When the target allocation ratio difference comparison result is that the target allocation ratio difference is greater than or equal to the first gradient limit and the target allocation ratio difference is less than or equal to the second gradient limit, the target allocation ratio is determined based on the adjacent allocation ratios.

[0021] In one embodiment, before the step of determining the torque distribution ratio threshold based on the current vehicle operating parameters and the distribution ratio mapping relationship upon receiving the drive mode switching command, the method further includes:

[0022] Perform dynamic analysis based on the vehicle's driving mode to determine key vehicle parameters;

[0023] The allocation ratio mapping relationship is obtained based on the vehicle's key parameters and the preset control variable strategy.

[0024] In one embodiment, the step of performing dynamic analysis based on the vehicle's driving mode to determine key vehicle parameters includes:

[0025] When the vehicle's driving mode is rear-wheel drive, a dynamic analysis of the vehicle is performed to obtain the rear-wheel drive analysis results.

[0026] When the vehicle's driving mode is four-wheel drive mode, a dynamic analysis of the vehicle is performed to obtain the four-wheel drive analysis results;

[0027] The key parameters of the vehicle are determined based on the rear-wheel drive analysis results and the four-wheel drive analysis results.

[0028] In one embodiment, the step of obtaining the allocation ratio mapping relationship based on key vehicle parameters and a preset control variable strategy includes:

[0029] The vehicle simulation results are obtained by performing working condition simulations based on key vehicle parameters and preset control variable strategies.

[0030] Based on the vehicle simulation results, determine the vehicle operating parameters and torque distribution ratio corresponding to the preset operating conditions;

[0031] A distribution ratio mapping relationship is generated based on the vehicle operating parameters corresponding to the preset operating conditions and the torque distribution ratio.

[0032] Furthermore, to achieve the above objectives, this application also proposes a torque control device for a four-wheel drive vehicle, the torque control device for the four-wheel drive vehicle comprising:

[0033] The processing module is used to determine the torque distribution ratio threshold based on the current vehicle operating parameters and the distribution ratio mapping relationship when a drive mode switching command is received;

[0034] The processing module is further configured to determine a target torque distribution ratio based on the current torque distribution ratio and the torque distribution ratio threshold.

[0035] The control module is used to control the torque of the four-wheel drive vehicle according to the target torque distribution ratio.

[0036] In addition, to achieve the above objectives, this application also proposes a torque control device for a four-wheel drive vehicle, the device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the torque control method for a four-wheel drive vehicle as described above.

[0037] In addition, to achieve the above objectives, this application also proposes a storage medium, which is a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the steps of the torque control method for a four-wheel drive vehicle as described above.

[0038] In addition, to achieve the above objectives, this application also provides a computer program product, which includes a computer program that, when executed by a processor, implements the steps of the torque control method for a four-wheel drive vehicle as described above.

[0039] This application determines a torque distribution ratio threshold based on current vehicle operating parameters and a distribution ratio mapping relationship upon receiving a drive mode switching command; determines a target torque distribution ratio based on the current torque distribution ratio and the threshold torque distribution ratio; and controls the torque of the four-wheel drive vehicle based on the target torque distribution ratio. By processing the distribution ratio during the switch from two-wheel drive to four-wheel drive, and ensuring that the torque loss due to the torque increment on the new drive shaft is compensated by the other drive shaft, torque filtering is achieved for the condition where the motor gear and shaft end gear are grinding, thus avoiding the occurrence of grinding. Attached Figure Description

[0040] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0041] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a flowchart illustrating an embodiment of the torque control method for a four-wheel drive vehicle according to this application.

[0043] Figure 2 This is a schematic diagram illustrating the platform limit for the torque distribution ratio provided in Embodiment 1 of the torque control method for four-wheel drive vehicles in this application;

[0044] Figure 3 This is a flowchart illustrating a second embodiment of the torque control method for a four-wheel drive vehicle according to this application.

[0045] Figure 4 This is a simplified schematic diagram showing the motion relationship between the vehicle and the front and rear motor gears and the front and rear axle end gears, as provided in Embodiment 2 of the torque control method for four-wheel drive vehicles of this application.

[0046] Figure 5This is a schematic diagram of vehicle dynamics analysis in rear-wheel drive mode provided in Embodiment 2 of the torque control method for four-wheel drive vehicles of this application;

[0047] Figure 6 This is a schematic diagram of the dynamic analysis of the front motor end gear in rear-wheel drive mode, provided as an embodiment of the torque control method for four-wheel drive vehicles in this application.

[0048] Figure 7 This is a schematic diagram of the dynamic analysis of the ABC system in rear-wheel drive mode, provided in Embodiment 2 of the torque control method for four-wheel drive vehicles of this application.

[0049] Figure 8 This is a schematic diagram of the dynamic analysis of the front motor end gear in four-wheel drive mode, provided as an embodiment of the torque control method for four-wheel drive vehicles in this application.

[0050] Figure 9 This is a schematic diagram of the dynamic analysis of D and ABC at the beginning of the torque control method for a four-wheel drive vehicle provided in Embodiment 2 of the present application;

[0051] Figure 10 This is a schematic diagram of the dynamic analysis of the ABC system in four-wheel drive mode provided in Embodiment 2 of the torque control method for four-wheel drive vehicles of this application.

[0052] Figure 11 A simplified flowchart illustrating the torque control method for a four-wheel drive vehicle provided in Embodiment 1 of this application;

[0053] Figure 12 This is a schematic diagram of the module structure of the torque control device for a four-wheel drive vehicle according to an embodiment of this application;

[0054] Figure 13 This is a schematic diagram of the equipment structure of the hardware operating environment involved in the torque control method for a four-wheel drive vehicle in this application embodiment.

[0055] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0056] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application.

[0057] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0058] The main solution of this application embodiment is: when a drive mode switching command is received, a torque distribution ratio threshold is determined based on the current vehicle operating parameters and the distribution ratio mapping relationship; a target torque distribution ratio is determined based on the current torque distribution ratio and the torque distribution ratio threshold; and the torque of the four-wheel drive vehicle is controlled based on the target torque distribution ratio.

[0059] When switching from rear-wheel drive to four-wheel drive in a four-wheel drive vehicle, the front wheels change from driven wheels to driving wheels. If torque control is not properly managed, gear grinding can easily occur. However, front axle gear grinding is not solely caused by torque crossing zero; the causes are more complex, and the grinding may occur even when torque has crossed zero. Therefore, completely avoiding gear grinding when switching from two-wheel drive to four-wheel drive has become a pressing issue.

[0060] This application determines a torque distribution ratio threshold based on current vehicle operating parameters and a distribution ratio mapping relationship upon receiving a drive mode switching command; determines a target torque distribution ratio based on the current torque distribution ratio and the threshold torque distribution ratio; and controls the torque of the four-wheel drive vehicle based on the target torque distribution ratio. By processing the distribution ratio during the switch from two-wheel drive to four-wheel drive, and ensuring that the torque loss due to the torque increment on the new drive shaft is compensated by the other drive shaft, torque filtering is achieved for the condition where the motor gear and shaft end gear are grinding, thus avoiding the occurrence of grinding.

[0061] It should be noted that the executing entity in this embodiment can be a computing service device with data processing, network communication, and program execution functions, such as a tablet computer, personal computer, or mobile phone, or a torque control device for a four-wheel drive vehicle capable of performing the above functions. The following description uses a torque control device for a four-wheel drive vehicle as the executing entity to illustrate this embodiment and the subsequent embodiments.

[0062] Based on this, embodiments of this application provide a torque control method for a four-wheel drive vehicle, referring to... Figure 1 , Figure 1 This is a flowchart illustrating the first embodiment of the torque control method for a four-wheel drive vehicle according to this application.

[0063] In this embodiment, the torque control method for the four-wheel drive vehicle includes steps S10 to S30:

[0064] Step S10: Upon receiving the drive mode switching command, determine the torque distribution ratio threshold based on the current vehicle operating parameters and the distribution ratio mapping relationship;

[0065] It should be noted that the drive mode switching command refers to the control command to switch from two-wheel drive mode to four-wheel drive mode. The current vehicle operating parameters include the total wheel torque, the current vehicle speed, and the current slope angle. The torque distribution ratio mapping relationship refers to the pre-set mapping relationship between the vehicle operating parameters and the torque distribution ratio. The torque distribution ratio threshold refers to the critical value of the torque distribution ratio corresponding to the current vehicle operating parameters.

[0066] In practice, when a control command is received to switch from two-wheel drive mode to four-wheel drive mode, the total wheel torque, current vehicle speed, and current slope angle corresponding to the current vehicle operation are obtained. Then, the pre-set mapping relationship between vehicle operating parameters and torque distribution ratio is used to query and obtain the critical value of torque distribution ratio corresponding to the current vehicle operating parameters.

[0067] Step S20: Determine the target torque distribution ratio based on the current torque distribution ratio and the torque distribution ratio threshold;

[0068] It is understandable that the current torque distribution ratio refers to the torque distribution ratio at which the vehicle is currently operating, while the target torque distribution ratio refers to the final four-wheel drive torque distribution ratio (the ratio of front wheel torque to total wheel-end torque).

[0069] In practice, the torque distribution ratio of the vehicle's current operation is compared with the critical value of the torque distribution ratio corresponding to the current vehicle operating parameters. When the torque distribution ratio of the vehicle's current operation is greater than or equal to the critical value of the torque distribution ratio corresponding to the current vehicle operating parameters, it indicates that a platform limit needs to be applied to the torque distribution ratio, thereby obtaining the final four-wheel drive torque distribution ratio.

[0070] In one feasible implementation, step S20 may include steps A21 to A23:

[0071] Step A21: Compare the current torque distribution ratio with the torque distribution ratio threshold to obtain the target comparison result;

[0072] It is understandable that the target comparison result refers to the comparison result between the current torque distribution ratio and the torque distribution ratio threshold.

[0073] In practice, the torque distribution ratio of the vehicle's current operation is compared with the critical value of the torque distribution ratio corresponding to the current vehicle operating parameters. This results in a comparison of whether the current torque distribution ratio of the vehicle is greater than or equal to the critical value of the torque distribution ratio corresponding to the current vehicle operating parameters, or whether the current torque distribution ratio of the vehicle is less than the critical value of the torque distribution ratio corresponding to the current vehicle operating parameters.

[0074] Step A22: When the target comparison result is that the current torque distribution ratio is greater than or equal to the torque distribution ratio threshold, the current torque distribution ratio is subjected to limit processing to obtain the limit distribution ratio;

[0075] It is understandable that the limit allocation ratio refers to the torque allocation ratio after the platform limit processing.

[0076] In practice, when the target comparison result is that the torque distribution ratio of the vehicle's current operation is greater than or equal to the critical value of the torque distribution ratio corresponding to the current vehicle operating parameters, it indicates that a platform limit needs to be applied to the torque distribution ratio. Then, a gradient limit is applied to the torque distribution ratio of the vehicle's current operation, and finally, the torque distribution ratio after the platform limit is applied is obtained.

[0077] Step A23: Determine the target torque distribution ratio based on at least one of the limit distribution ratio, the first gradient limit, and the second gradient limit, wherein the second gradient limit is greater than the first gradient limit.

[0078] It is understandable that the first gradient limit refers to the torque distribution ratio corresponding to the maximum allowable negative rate of change, and the second gradient limit refers to the torque distribution ratio corresponding to the maximum allowable positive rate of change.

[0079] In practice, the torque distribution ratio after platform limit processing is compared with the torque distribution ratio corresponding to the maximum allowable negative rate of change and the torque distribution ratio corresponding to the maximum allowable positive rate of change. Then, gradient limit processing is performed based on the comparison results, and finally the final four-wheel drive torque distribution ratio (the ratio of front wheel torque to total wheel end torque) is obtained.

[0080] In one feasible implementation, step A23 may include steps B231 to B233:

[0081] Step B231: Calculate the target allocation ratio difference based on the difference between the limit allocation ratio and the adjacent allocation ratio;

[0082] It is understandable that the adjacent allocation ratio refers to the torque allocation ratio at the next moment, and the target allocation ratio difference refers to the difference between the current allocation ratio and the adjacent allocation ratio.

[0083] In practice, to avoid sudden torque changes affecting drivability, the torque distribution ratio after platform limit processing needs to be gradient-limited to obtain the torque distribution ratio at the next moment. Then, the difference between the torque distribution ratio after platform limit processing and the torque distribution ratio at the next moment is calculated to obtain the target distribution ratio difference.

[0084] Step B232: Compare the target allocation ratio difference with the first gradient limit and the second gradient limit respectively to obtain the allocation ratio difference comparison result;

[0085] It is understandable that the distribution ratio difference comparison result refers to the comparison result of the torque distribution ratio change rate corresponding to the target distribution ratio difference with the first gradient limit and the second gradient limit.

[0086] In practice, the difference rate between the current allocation ratio and the adjacent allocation ratio is compared with the torque allocation ratio corresponding to the maximum allowable negative change rate and the torque allocation ratio corresponding to the maximum allowable positive change rate, respectively, and finally the allocation ratio difference comparison result is obtained.

[0087] Step B233: Determine the target allocation ratio based on at least one of the allocation ratio difference comparison result, the adjacent allocation ratio, the limit allocation ratio, the first gradient limit, and the second gradient limit.

[0088] Understandably, based on the comparison results between different target distribution ratio differences and the first gradient limit and the second gradient limit, at least one of the adjacent distribution ratio, limit distribution ratio, first gradient limit and second gradient limit is selected to calculate the distribution ratio, and the final four-wheel drive torque distribution ratio is obtained.

[0089] In one feasible implementation, step B233 may include steps C2331 to C2333:

[0090] Step C2331: When the target allocation ratio difference is less than the first gradient limit, the target allocation ratio is determined based on the limit allocation ratio and the first gradient limit.

[0091] Understandably, when the target distribution ratio difference is less than the torque distribution ratio corresponding to the maximum allowable negative rate of change, the target distribution ratio is obtained by summing the torque distribution ratio after platform limit processing and the torque distribution ratio corresponding to the maximum allowable negative rate of change.

[0092] Step C2332: When the target allocation ratio difference is greater than the second gradient limit, the target allocation ratio is determined based on the limit allocation ratio and the second gradient limit.

[0093] Understandably, when the target distribution ratio difference is greater than the torque distribution ratio corresponding to the maximum allowable positive rate of change, the target distribution ratio is obtained by summing the torque distribution ratio after platform limit processing and the torque distribution ratio corresponding to the maximum allowable positive rate of change.

[0094] Step C2333: When the target allocation ratio difference comparison result is that the target allocation ratio difference is greater than or equal to the first gradient limit and the target allocation ratio difference is less than or equal to the second gradient limit, the target allocation ratio is determined according to the adjacent allocation ratio.

[0095] It is understandable that when the result of the distribution ratio difference comparison is that the target distribution ratio difference is greater than or equal to the torque distribution ratio corresponding to the maximum allowable negative rate of change, and the result of the distribution ratio difference comparison is that the target distribution ratio difference is less than or equal to the torque distribution ratio corresponding to the maximum allowable positive rate of change, the target distribution ratio is obtained based on the torque distribution ratio at the next moment.

[0096] It should be noted that the first step is to determine whether the flag for switching from two-wheel drive to four-wheel drive is activated. If the flag is activated at this time, the expected allocation ratio at this point needs to be determined based on the current situation. The platform is processed; the second step is to determine the total wheel end torque T at this point. Whl_total Vehicle speed v and slope angle The query yields the critical value of the allocation ratio. The third step is when the expected allocation ratio reaches the critical value of the allocation ratio. The demand allocation ratio is capped by the platform. Based on experience, such as... Figure 2 As shown, when the expected allocation ratio K desired Reaching the critical value of the distribution ratio After processing, the allocation ratio K desried_dealed It needs to be limited to +0.025, approximately 0.15s later, then follow the expected allocation ratio K. desired Step 4, K desried_dealed Gradient limiting is required to prevent sudden torque changes from affecting drivability. Based on discrete control methods, if K... desried_dealed (n+1)-K desried_dealed (n) <K negative_gradient_limit Then K desired_filtered =K desried_dealed (n)+K negative_gradient_limit If K desried_dealed (n+1)-K desried_dealed (n)>K Positive_gradient_limit Then K desired_filtered =K desried_dealed (n)+K Positive_gradient_limit If K negative_gradient_limit <K desried_dealed (n+1)-K desried_dealed (n) <K Positive_gradient_limit Then K desired_filtered =K desried_dealed (n+1); Step 5, K desired_filtere d is output as the target allocation ratio.

[0097] Understandably, to avoid gear grinding, most current control methods directly process the torque request at the wheel ends, which limits the vehicle's power response. However, this embodiment processes the distribution ratio, so during the 2WD to 4WD switch, the torque loss on the new drive shaft due to the limited torque is compensated by the other drive shaft. Therefore, during four-wheel drive switching, the vehicle experiences no power loss or lag.

[0098] Step S30: Control the torque of the four-wheel drive vehicle according to the target torque distribution ratio.

[0099] It is understood that the torque distribution ratio in this embodiment refers to the ratio of the front wheel torque to the total wheel end torque. Then, the total wheel end torque is distributed according to the calculated final torque distribution ratio to obtain the magnitude of the front wheel torque and rear wheel torque of the vehicle. That is, the torque of the vehicle switching from two-wheel drive mode to four-wheel drive mode is filtered to avoid gear grinding.

[0100] This embodiment determines a torque distribution ratio threshold based on the current vehicle operating parameters and the distribution ratio mapping relationship upon receiving a drive mode switching command; determines a target torque distribution ratio based on the current torque distribution ratio and the threshold torque distribution ratio; and controls the torque of the four-wheel drive vehicle based on the target torque distribution ratio. By processing the distribution ratio during the switch from two-wheel drive to four-wheel drive, and ensuring that the torque loss due to the torque increment on the new drive shaft is compensated by the other drive shaft, torque filtering is achieved for the condition where the motor gear and shaft end gear are grinding, thus avoiding the occurrence of grinding.

[0101] Based on the first embodiment of this application, in the second embodiment of this application, the content that is the same as or similar to that in the first embodiment described above can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 3 Before step S10, the torque control method for the four-wheel drive vehicle further includes steps S01~S02:

[0102] Step S01: Perform dynamic analysis based on the vehicle's driving mode to determine key vehicle parameters;

[0103] It is understandable that vehicle drive modes include two-wheel drive mode and four-wheel drive mode. Vehicle key parameters refer to the vehicle operating parameters that affect the torque distribution ratio, and vehicle key parameters include total wheel torque, current vehicle speed, and current slope angle.

[0104] In practice, dynamic analysis is performed under different vehicle drive modes, and the vehicle operating parameters that affect the torque distribution ratio are determined based on the analysis results, namely the total wheel-end torque, the current vehicle speed, and the current slope angle.

[0105] In one feasible implementation, step S01 may include steps A011 to A013:

[0106] Step A011: When the vehicle driving mode is rear-wheel drive, perform dynamic analysis on the vehicle to obtain the rear-wheel drive analysis results.

[0107] Understandably, when the vehicle's drive mode is rear-wheel drive (two-wheel drive), the vehicle's power is provided solely by the rear motor. When the rear motor's gear and the rear axle's gear engage with other moving parts, the rear motor's gear drives both the rear axle gear and its associated moving parts, as well as the front axle gear and its associated moving parts. This, in turn, drives the front motor's gear, causing the entire system to move together. This leads to the final dynamic analysis results for the rear-wheel drive mode.

[0108] Step A012: When the vehicle driving mode is four-wheel drive mode, perform dynamic analysis on the vehicle to obtain the four-wheel drive analysis results.

[0109] It is understandable that when the vehicle is in four-wheel drive mode, both the rear motor gear and the front motor gear have the ability to provide power, thus making the entire system move together, and finally obtaining the dynamic analysis results of the four-wheel drive mode.

[0110] Step A013: Determine the key vehicle parameters based on the rear-wheel drive analysis results and the four-wheel drive analysis results.

[0111] In practice, the dynamic analysis results of the vehicle's rear-wheel drive mode and the dynamic analysis results of the vehicle's four-wheel drive mode are summarized and analyzed to determine the vehicle operating parameters that affect the torque distribution ratio, namely the total wheel-end torque, the current vehicle speed, and the current slope angle.

[0112] It should be noted that the motion model of a vehicle is extremely complex, especially when internal rotating parts are involved, the dynamic model can become so complex that physical analysis is impossible. This embodiment uses a simplified model for analysis. The motion relationship between the entire vehicle and the front and rear motor gears and the front and rear axle end gears is simplified as follows: Figure 4 The configuration is shown below. A represents the system consisting of the rear axle end gear and other moving parts, B represents the rear motor end gear, C represents the system consisting of the front axle end gear and other moving parts, and D represents the front motor end gear. A and C are rigidly connected.

[0113] It should be noted that the dynamic analysis in rear-wheel drive mode is as follows: Figure 5 As shown. The driving force of the entire system is provided solely by B. When B and A come into contact, B pushes A and C to move, and C then pushes D to move. This causes the entire system to move together. The acceleration of the entire system... .like Figure 6 As shown, the force analysis for D is as follows (the resistance on the surface where C and D move relative to each other is very small and can be ignored): .like Figure 7 As shown, analyze the ABC system: ,at this time, = = .

[0114] It is understandable that when switching from rear-wheel drive to four-wheel drive, that is, when both B and D have the ability to provide power, such as Figure 8 As shown, when D initially provides power, due to the deformation of the non-rigid body, C and D cannot immediately separate. An interaction force still exists between C and D. However, the acceleration of D cannot exceed the acceleration of the entire system, so D still cannot separate from C. Furthermore, due to deformation, the interaction force between C and D... Extremely difficult to analyze. When D and C can be completely separated, there is no longer an interaction force between the D and ABC system. The dynamic analysis of the D and ABC system is as follows: Figure 9 As shown, At this point, the dynamic analysis of the ABC system is as follows: Figure 10 As shown, ,when When the value is greater than 0, D and C will separate, analogous to the separation of the front axle motor end gear surface and the front axle shaft end gear surface. To make... > ,make , Applying this simplified model to the entire vehicle system, when the front axle motor end gear surface and the front axle shaft end gear surface are separated, the following formula is satisfied:

[0115]

[0116]

[0117] >

[0118] After simplification, we get:

[0119]

[0120] +

[0121] =f roll (v, m,fr)

[0122] = f slope ( ) =

[0123] in, Angular acceleration at the P3 motor end, : Total wheel-end torque, k : Four-wheel drive distribution ratio (ratio of front wheel torque to total wheel-end torque) Front axle reduction ratio The total moment of inertia of the P3 motor and the connecting gear system. R: Vehicle acceleration, Wheel radius The remaining mass of the vehicle after removing the P3 motor. Rotational mass correction factor Rolling resistance : Gradient resistance Wind resistance.

[0124] It should be understood that, based on the above analysis, with fixed vehicle parameters, the vehicle mass *m* and the frontal area *A* are also constant. The rolling resistance coefficient is affected by the wheel surface environment, and in most common road conditions, it is a constant between 0.015 and 0.02. In summary, with fixed vehicle parameters, rolling resistance depends only on vehicle speed, gradient resistance depends only on the gradient angle, and wind resistance depends only on vehicle speed. Based on this formula... Therefore, it can be seen that the condition for whether the front axle motor gear can separate from the shaft end gear surface when switching from two-wheel drive to four-wheel drive only needs to consider the four-wheel drive distribution ratio k. This is under the condition that the overall vehicle parameters are constant. The change in the value is only related to the total torque at the wheel end. Vehicle speed v and slope angle related.

[0125] Step S02: Obtain the allocation ratio mapping relationship based on the vehicle key parameters and the preset control variable strategy.

[0126] It is understandable that the preset control variable strategy refers to the pre-defined calibration strategy for control variables.

[0127] In practice, based on the total wheel-end torque, current vehicle speed, and current slope angle, bench or real-vehicle tests are conducted using the controlled variable method to determine the corresponding total wheel-end torque T for each gear engagement. Whl_total Vehicle speed v, slope angle And the torque distribution ratio k, thus generating the mapping relationship of the torque distribution ratio.

[0128] In one feasible implementation, step S02 may include steps A021 to A023:

[0129] Step A021: Perform a working condition simulation based on the vehicle's key parameters and preset control variable strategy to obtain the vehicle simulation results;

[0130] Understandably, the vehicle simulation results include the total wheel-end torque T corresponding to each gear-gripping condition. Whl_total Vehicle speed v, slope angle And the torque distribution ratio k.

[0131] In practice, based on the total wheel-end torque, current vehicle speed, and current slope angle, bench or real-vehicle tests are conducted using the controlled variable method to simulate various gear-grinding conditions, thereby obtaining the corresponding total wheel-end torque T for each gear-grinding condition. Whl_total Vehicle speed v, slope angle And the torque distribution ratio k, which is the result of vehicle simulation.

[0132] Step A022: Determine the vehicle operating parameters and torque distribution ratio corresponding to the preset working conditions based on the vehicle simulation results;

[0133] It is understandable that the preset operating condition refers to the pre-set gear grinding condition, and the vehicle operating parameters include the total wheel end torque T. Whl_total Vehicle speed v, slope angle The torque distribution ratio refers to the torque distribution ratio corresponding to the gear grinding operation.

[0134] Step A023: Generate a distribution ratio mapping relationship based on the vehicle operating parameters corresponding to the preset working conditions and the torque distribution ratio.

[0135] In practice, by considering each gear-cutting condition with the total wheel end torque T... Whl_total Vehicle speed v, slope angle And the torque distribution ratio k corresponds one-to-one, thereby generating the mapping relationship of the torque distribution ratio.

[0136] It should be noted that in this embodiment, the condition for whether the front axle motor gear can separate from the shaft end gear surface when switching from two-wheel drive to four-wheel drive only needs to consider the four-wheel drive distribution ratio k. The critical value of this distribution ratio is only related to the total wheel end torque T. Whl_total Vehicle speed v and slope angle Relevant. Through bench or real-vehicle testing, using the controlled variable method, the total wheel end torque T corresponding to each gear engagement can be determined. Whl_total Vehicle speed v and slope angle And the distribution ratio k. Different total wheel end torques T are obtained. Whl_total Vehicle speed v and slope angle The corresponding critical value of the allocation ratio . =Map(T) Whl_total ).

[0137] This embodiment performs dynamic analysis based on the vehicle's driving mode to determine key vehicle parameters; and obtains the torque distribution ratio mapping relationship based on the key vehicle parameters and a preset control variable strategy. By performing dynamic analysis on the vehicle's rear-wheel drive mode and four-wheel drive mode respectively, the parameters affecting the torque distribution coefficient are determined, and then a torque distribution ratio mapping relationship is generated through a control variable strategy. Finally, the distribution ratio is processed to ensure that there is no power loss or response lag when switching to four-wheel drive.

[0138] For example, to help understand the implementation process of the torque control method for a four-wheel drive vehicle obtained by combining this embodiment with the above-described embodiment one, please refer to... Figure 11 , Figure 11 A simplified flowchart of a torque control method for a four-wheel drive vehicle is provided. Specifically: First, it is necessary to determine whether the flag for switching from two-wheel drive to four-wheel drive is activated. If the flag is activated, the expected allocation ratio at this time needs to be determined based on the current situation. The platform is processed; the second step is to determine the total wheel end torque T at this point. Whl_total Vehicle speed v and slope angle The query yields the critical value of the allocation ratio. The third step is when the expected allocation ratio reaches the critical value of the allocation ratio. The demand allocation ratio is capped by the platform. Based on experience, such as... Figure 2 As shown, when the expected allocation ratio K desired Reaching the critical value of the distribution ratio After processing, the allocation ratio K desried_dealed It needs to be limited to +0.025, approximately 0.15s later, then follow the expected allocation ratio K. desired Step 4, K desried_dealed Gradient limiting is required to prevent sudden torque changes from affecting drivability. Based on discrete control methods, if K... desried_dealed (n+1)-K desried_dealed (n) <K negative_gradient_limit Then K desired_filtered =K desried_dealed (n)+K negative_gradient_limit If K desried_dealed (n+1)-K desried_dealed (n)>K Positive_gradient_limit Then K desired_filtered =K desried_dealed (n)+K Positive_gradient_limit If K negative_gradient_limit <K desried_dealed (n+1)-K desried_dealed (n) <K Positive_gradient_limit Then K desired_filtered =K desried_dealed(n+1); Step 5, K desired_filtere d is output as the target allocation ratio.

[0139] It should be noted that the above examples are only for understanding this application and do not constitute a limitation on the torque control method of the four-wheel drive vehicle of this application. Any simple modifications based on this technical concept are within the protection scope of this application.

[0140] This application also provides a torque control device for a four-wheel drive vehicle, please refer to... Figure 12 The torque control device for the four-wheel drive vehicle includes:

[0141] Processing module 10 is used to determine the torque distribution ratio threshold based on the current vehicle operating parameters and the distribution ratio mapping relationship when a drive mode switching command is received;

[0142] The processing module 10 is further configured to determine a target torque distribution ratio based on the current torque distribution ratio and the torque distribution ratio threshold.

[0143] The control module 20 is used to control the torque of the four-wheel drive vehicle according to the target torque distribution ratio.

[0144] Optionally, the processing module 10 is further configured to:

[0145] The current torque distribution ratio is compared with the torque distribution ratio threshold to obtain the target comparison result;

[0146] When the target comparison result is that the current torque distribution ratio is greater than or equal to the torque distribution ratio threshold, the current torque distribution ratio is subjected to limit processing to obtain the limit distribution ratio;

[0147] The target torque distribution ratio is determined based on at least one of the limit distribution ratio, the first gradient limit, and the second gradient limit, wherein the second gradient limit is greater than the first gradient limit.

[0148] Optionally, the processing module 10 is further configured to:

[0149] The target allocation ratio difference is obtained by calculating the difference between the limit allocation ratio and the adjacent allocation ratio.

[0150] The target allocation ratio difference is compared with the first gradient limit and the second gradient limit respectively to obtain the allocation ratio difference comparison result;

[0151] The target allocation ratio is determined based on at least one of the following: the allocation ratio difference comparison result, the adjacent allocation ratio, the limit allocation ratio, the first gradient limit, and the second gradient limit.

[0152] Optionally, the processing module 10 is further configured to:

[0153] When the target allocation ratio difference is less than the first gradient limit, the target allocation ratio is determined based on the limit allocation ratio and the first gradient limit.

[0154] When the target allocation ratio difference is greater than the second gradient limit, the target allocation ratio is determined based on the limit allocation ratio and the second gradient limit.

[0155] When the target allocation ratio difference comparison result is that the target allocation ratio difference is greater than or equal to the first gradient limit and the target allocation ratio difference is less than or equal to the second gradient limit, the target allocation ratio is determined based on the adjacent allocation ratios.

[0156] Optionally, the processing module 10 is further configured to:

[0157] Perform dynamic analysis based on the vehicle's driving mode to determine key vehicle parameters;

[0158] The allocation ratio mapping relationship is obtained based on the vehicle's key parameters and the preset control variable strategy.

[0159] Optionally, the processing module 10 is further configured to:

[0160] When the vehicle's driving mode is rear-wheel drive, a dynamic analysis of the vehicle is performed to obtain the rear-wheel drive analysis results.

[0161] When the vehicle's driving mode is four-wheel drive mode, a dynamic analysis of the vehicle is performed to obtain the four-wheel drive analysis results;

[0162] The key parameters of the vehicle are determined based on the rear-wheel drive analysis results and the four-wheel drive analysis results.

[0163] Optionally, the processing module 10 is further configured to:

[0164] The vehicle simulation results are obtained by performing working condition simulations based on key vehicle parameters and preset control variable strategies.

[0165] Based on the vehicle simulation results, determine the vehicle operating parameters and torque distribution ratio corresponding to the preset operating conditions;

[0166] A distribution ratio mapping relationship is generated based on the vehicle operating parameters corresponding to the preset operating conditions and the torque distribution ratio.

[0167] The torque control device for four-wheel drive vehicles provided in this application, employing the torque control method for four-wheel drive vehicles described in the above embodiments, can solve the technical problem of how to completely avoid gear grinding when switching from two-wheel drive mode to four-wheel drive mode. Compared with the prior art, the beneficial effects of the torque control device for four-wheel drive vehicles provided in this application are the same as those of the torque control method for four-wheel drive vehicles provided in the above embodiments, and other technical features in the torque control device for four-wheel drive vehicles are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.

[0168] This application provides a torque control device for a four-wheel drive vehicle. The torque control device for a four-wheel drive vehicle includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the torque control method for a four-wheel drive vehicle as described in Embodiment 1 above.

[0169] The following is for reference. Figure 13 This document illustrates a structural schematic diagram of a torque control device suitable for implementing embodiments of the present application in a four-wheel drive vehicle. The torque control device for the four-wheel drive vehicle in the embodiments of the present application may include, but is not limited to, mobile terminals such as mobile phones, laptops, digital radio receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Description), PMPs (Portable Media Players), in-vehicle terminals (e.g., in-vehicle navigation terminals), and fixed terminals such as digital TVs and desktop computers. Figure 13 The torque control device for the four-wheel drive vehicle shown is merely an example and should not be construed as limiting the functionality and scope of the embodiments of this application.

[0170] like Figure 13As shown, the torque control device of a four-wheel drive vehicle may include a processing unit 1001 (e.g., a central processing unit, a graphics processor, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1002 or a program loaded from a storage device 1003 into a random access memory (RAM) 1004. The RAM 1004 also stores various programs and data required for the operation of the torque control device of the four-wheel drive vehicle. The processing unit 1001, ROM 1002, and RAM 1004 are interconnected via a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Typically, the following systems can be connected to I / O interface 1006: input devices 1007 including, for example, touchscreens, touchpads, keyboards, mice, image sensors, microphones, accelerometers, gyroscopes, etc.; output devices 1008 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; storage devices 1003 including, for example, magnetic tapes, hard disks, etc.; and communication devices 1009. Communication device 1009 allows the torque control device of a four-wheel drive vehicle to communicate wirelessly or wiredly with other devices to exchange data. Although the figure shows a torque control device for a four-wheel drive vehicle with various systems, it should be understood that it is not required to implement or possess all the systems shown. More or fewer systems may be implemented or possessed alternatively.

[0171] Specifically, according to the embodiments disclosed in this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments disclosed in this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication device, or installed from storage device 1003, or installed from ROM 1002. When the computer program is executed by processing device 1001, it performs the functions defined in the methods of the embodiments disclosed in this application.

[0172] The torque control device for four-wheel drive vehicles provided in this application, employing the torque control method for four-wheel drive vehicles described in the above embodiments, can solve the technical problem of how to completely avoid gear grinding when switching from two-wheel drive mode to four-wheel drive mode. Compared with the prior art, the beneficial effects of the torque control device for four-wheel drive vehicles provided in this application are the same as those of the torque control method for four-wheel drive vehicles provided in the above embodiments, and other technical features of the torque control device for four-wheel drive vehicles are the same as those disclosed in the previous embodiment method, and will not be repeated here.

[0173] It should be understood that the various parts disclosed in this application can be implemented using hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0174] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0175] This application provides a computer-readable storage medium having computer-readable program instructions (i.e., a computer program) stored thereon, the computer-readable program instructions being used to execute the torque control method for a four-wheel drive vehicle in the above embodiments.

[0176] The computer-readable storage medium provided in this application may be, for example, a USB flash drive, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, system, or device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0177] The aforementioned computer-readable storage medium may be included in the torque control device of a four-wheel drive vehicle; or it may exist independently and not be installed in the torque control device of a four-wheel drive vehicle.

[0178] The aforementioned computer-readable storage medium carries one or more programs that, when executed by the torque control device of a four-wheel drive vehicle, cause the torque control device of the four-wheel drive vehicle to: upon receiving a drive mode switching command, determine a torque distribution ratio threshold based on the current vehicle operating parameters and the distribution ratio mapping relationship; determine a target torque distribution ratio based on the current torque distribution ratio and the torque distribution ratio threshold; and control the torque of the four-wheel drive vehicle based on the target torque distribution ratio.

[0179] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a Local Area Network (LAN) or a Wide Area Network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0180] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0181] The modules described in the embodiments of this application can be implemented in software or hardware. The names of the modules do not necessarily limit the functionality of the unit itself.

[0182] The readable storage medium provided in this application is a computer-readable storage medium that stores computer-readable program instructions (i.e., a computer program) for executing the torque control method for the four-wheel drive vehicle described above. This solves the technical problem of how to completely avoid gear grinding when switching from two-wheel drive mode to four-wheel drive mode. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in this application are the same as those of the torque control method for the four-wheel drive vehicle provided in the above embodiments, and will not be repeated here.

[0183] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the torque control method for a four-wheel drive vehicle as described above.

[0184] The computer program product provided in this application can solve the technical problem of how to completely avoid gear grinding when switching from two-wheel drive mode to four-wheel drive mode. Compared with the prior art, the beneficial effects of the computer program product provided in this application are the same as the beneficial effects of the torque control method for four-wheel drive vehicles provided in the above embodiments, and will not be repeated here.

[0185] The above description is only a part of the embodiments of this application and does not limit the patent scope of this application. All equivalent structural transformations made under the technical concept of this application and using the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included in the patent protection scope of this application.

Claims

1. A torque control method for a four-wheel drive vehicle, characterized in that, The torque control method for the four-wheel drive vehicle includes: Upon receiving a drive mode switching command, the torque distribution ratio threshold is determined based on the current vehicle operating parameters and the distribution ratio mapping relationship; The target torque distribution ratio is determined based on the current torque distribution ratio and the torque distribution ratio threshold. The torque of the four-wheel drive vehicle is controlled according to the target torque distribution ratio; The step of determining the target torque distribution ratio based on the current torque distribution ratio and the torque distribution ratio threshold includes: The current torque distribution ratio is compared with the torque distribution ratio threshold to obtain the target comparison result; When the target comparison result is that the current torque distribution ratio is greater than or equal to the torque distribution ratio threshold, the current torque distribution ratio is subjected to limit processing to obtain the limit distribution ratio; The target torque distribution ratio is determined based on at least one of the limit distribution ratio, the first gradient limit, and the second gradient limit, wherein the second gradient limit is greater than the first gradient limit. The step of determining the target torque distribution ratio based on at least one of the limit distribution ratio, the first gradient limit, and the second gradient limit includes: The target allocation ratio difference is obtained by calculating the difference between the limit allocation ratio and the adjacent allocation ratio. The target allocation ratio difference is compared with the first gradient limit and the second gradient limit respectively to obtain the allocation ratio difference comparison result; The target allocation ratio is determined based on at least one of the following: the allocation ratio difference comparison result, the adjacent allocation ratio, the limit allocation ratio, the first gradient limit, and the second gradient limit. The step of determining the target allocation ratio based on at least one of the allocation ratio difference comparison result, the adjacent allocation ratio, the limit allocation ratio, the first gradient limit, and the second gradient limit includes: When the target allocation ratio difference is less than the first gradient limit, the target allocation ratio is determined based on the limit allocation ratio and the first gradient limit. When the target allocation ratio difference is greater than the second gradient limit, the target allocation ratio is determined based on the limit allocation ratio and the second gradient limit. When the target allocation ratio difference comparison result is that the target allocation ratio difference is greater than or equal to the first gradient limit and the target allocation ratio difference is less than or equal to the second gradient limit, the target allocation ratio is determined based on the adjacent allocation ratios.

2. The method as described in claim 1, characterized in that, Before the step of determining the torque distribution ratio threshold based on the current vehicle operating parameters and the distribution ratio mapping relationship upon receiving the drive mode switching command, the method further includes: Perform dynamic analysis based on the vehicle's driving mode to determine key vehicle parameters; The allocation ratio mapping relationship is obtained based on the vehicle's key parameters and the preset control variable strategy.

3. The method as described in claim 2, characterized in that, The step of performing dynamic analysis based on the vehicle's driving mode to determine key vehicle parameters includes: When the vehicle's driving mode is rear-wheel drive, a dynamic analysis of the vehicle is performed to obtain the rear-wheel drive analysis results. When the vehicle's driving mode is four-wheel drive mode, a dynamic analysis of the vehicle is performed to obtain the four-wheel drive analysis results; The key parameters of the vehicle are determined based on the rear-wheel drive analysis results and the four-wheel drive analysis results.

4. The method as described in claim 2, characterized in that, The step of obtaining the allocation ratio mapping relationship based on key vehicle parameters and a preset control variable strategy includes: The vehicle simulation results are obtained by performing working condition simulations based on key vehicle parameters and preset control variable strategies. Based on the vehicle simulation results, determine the vehicle operating parameters and torque distribution ratio corresponding to the preset operating conditions; A distribution ratio mapping relationship is generated based on the vehicle operating parameters corresponding to the preset operating conditions and the torque distribution ratio.

5. A torque control device for a four-wheel drive vehicle, the device being configured to implement the torque control method for a four-wheel drive vehicle as described in any one of claims 1 to 4, characterized in that, The device includes: The processing module is used to determine the torque distribution ratio threshold based on the current vehicle operating parameters and the distribution ratio mapping relationship when a drive mode switching command is received; The processing module is further configured to determine a target torque distribution ratio based on the current torque distribution ratio and the torque distribution ratio threshold. The control module is used to control the torque of the four-wheel drive vehicle according to the target torque distribution ratio.

6. A torque control device for a four-wheel drive vehicle, characterized in that, The device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the torque control method for a four-wheel drive vehicle as claimed in any one of claims 1 to 4.

7. A storage medium, characterized in that, The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, it implements the steps of the torque control method for a four-wheel drive vehicle as described in any one of claims 1 to 4.

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