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

Abstract

The invention discloses a torque control method, device and equipment of a four-wheel-drive vehicle and a storage medium, and relates to the technical field of vehicles, and the torque control method of the four-wheel-drive vehicle comprises the steps that when a driving mode switching instruction is received, a torque distribution ratio threshold value is determined according to current vehicle operation parameters and a distribution ratio mapping relation; determining a target torque distribution ratio according to the current torque distribution ratio and the torque distribution ratio threshold value; and controlling the torque of the four-wheel-drive vehicle according to the target torque distribution ratio. The distribution ratio is processed in the switching process from two-wheel drive to four-wheel drive, and the torque lost by the torque increment on the new drive shaft in the limited process is compensated by the other drive shaft, so that torque filtering is carried out on the working condition of tooth beating of the motor gear and the shaft end gear, and the tooth beating phenomenon is avoided.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a torque control method, device, equipment and storage medium for a four-wheel drive vehicle. Background Art

[0002] At present, in order to further improve the power and operating experience of new energy vehicles, more and more new energy vehicles have adopted a four-wheel drive configuration with front and rear dual motors. In some four-wheel drive allocation strategies that pursue optimal energy consumption, the vehicle is not required to use four-wheel drive throughout the entire driving process. In order to optimize economy, rear-wheel drive will be used at low speeds, and four-wheel drive will be used when the speed increases. At this time, the tooth gap between the transmission gears connected to the motor will cause teeth to play due to rapid impact. It is worth noting that at present, people often only notice the tooth playing caused by the motor torque passing through zero when the vehicle starts, or the sudden change in torque direction during energy recovery. In both cases, tooth playing is caused by torque passing through zero.

[0003] When a four-wheel drive vehicle switches from rear-wheel drive to four-wheel drive, when the front wheel changes from a driven wheel to a driving wheel, if the torque is not well controlled, it is easy to cause a gear knocking shock. However, the front axle's gear knocking shock is not only caused by the torque crossing zero. The reasons for this kind of gear knocking are more complicated. The point of gear knocking is not when the torque crosses zero. Even if the torque has passed zero, it may still occur. Therefore, how to completely avoid the gear knocking phenomenon when switching from two-wheel drive mode to four-wheel drive mode has become an urgent problem to be solved. Summary of the invention

[0004] The main purpose of the present 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 the gear-clutching phenomenon when switching from a two-wheel drive mode to a four-wheel drive mode.

[0005] To achieve the above object, the present application proposes a torque control method for a four-wheel drive vehicle, the torque control method for a four-wheel drive vehicle comprising: When receiving a driving mode switching instruction, determining a torque distribution ratio threshold value according to current vehicle operating parameters and a distribution ratio mapping relationship; determining a target torque distribution ratio according to 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.

[0006] In one embodiment, the step of determining the target torque distribution ratio according to the current torque distribution ratio and the torque distribution ratio threshold comprises: Comparing the current torque distribution ratio with the torque distribution ratio threshold to obtain a 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, performing limit processing on the current torque distribution ratio to obtain a limit distribution ratio; The target torque distribution ratio is determined according to at least one of the limit distribution ratio, a first gradient limit value, and a second gradient limit value, the second gradient limit value being greater than the first gradient limit value.

[0007] In one embodiment, the step of determining the target torque distribution ratio according to at least one of the limit distribution ratio, the first gradient limit and the second gradient limit comprises: Calculate the difference between the limit allocation ratio and the adjacent allocation ratio to obtain a target allocation ratio difference; Comparing the target allocation ratio difference with the first gradient limit value and the second gradient limit value respectively to obtain an allocation ratio difference comparison result; A target allocation ratio is determined according to 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.

[0008] In one embodiment, the step of determining the target allocation ratio according to 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 comprises: When the allocation ratio difference comparison result is that the target allocation ratio difference is less than the first gradient limit value, determining the target allocation ratio according to the limit allocation ratio and the first gradient limit value; When the allocation ratio difference comparison result is that the target allocation ratio difference is greater than the second gradient limit, determining the target allocation ratio according to the limit allocation ratio and the second gradient limit; When the allocation ratio difference comparison result is that the target allocation ratio difference is greater than or equal to the first gradient limit value and the target allocation ratio difference is less than or equal to the second gradient limit value, the target allocation ratio is determined according to the adjacent allocation ratios.

[0009] In one embodiment, before the step of determining the torque distribution ratio threshold according to the current vehicle operating parameters and the distribution ratio mapping relationship when the driving mode switching instruction is received, the method further includes: Conduct dynamic analysis based on vehicle driving modes to determine key vehicle parameters; The allocation ratio mapping relationship is obtained according to the key vehicle parameters and the preset control variable strategy.

[0010] In one embodiment, the step of performing dynamic analysis according to the vehicle driving mode to determine the key parameters of the vehicle includes: When the vehicle driving mode is a rear-wheel drive mode, a dynamic analysis is performed on the vehicle to obtain a rear-wheel drive analysis result; When the vehicle driving mode is a four-wheel drive mode, a dynamic analysis is performed on the vehicle to obtain a four-wheel drive analysis result; The key parameters of the vehicle are determined according to the rear-wheel drive analysis results and the four-wheel drive analysis results.

[0011] In one embodiment, the step of obtaining the allocation ratio mapping relationship according to the key vehicle parameters and the preset control variable strategy includes: Perform working condition simulation based on key vehicle parameters and preset control variable strategies to obtain vehicle simulation results; Determining vehicle operating parameters and torque distribution ratios corresponding to a preset operating condition according to the vehicle simulation results; A distribution ratio mapping relationship is generated according to the vehicle operating parameters corresponding to the preset operating condition and the torque distribution ratio.

[0012] In addition, to achieve the above purpose, the present application also proposes a torque control device for a four-wheel drive vehicle, the torque control device for the four-wheel drive vehicle comprising: A processing module, configured to determine a torque distribution ratio threshold value according to current vehicle operating parameters and a distribution ratio mapping relationship when receiving a driving mode switching instruction; The processing module is further used to determine a target torque distribution ratio according to the current torque distribution ratio and the torque distribution ratio threshold; A control module is used to control the torque of the four-wheel drive vehicle according to the target torque distribution ratio.

[0013] In addition, to achieve the above-mentioned purpose, the present 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.

[0014] In addition, to achieve the above-mentioned purpose, the present application also proposes a storage medium, which 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, the steps of the torque control method of the four-wheel drive vehicle as described above are implemented.

[0015] In addition, to achieve the above-mentioned purpose, the present application also provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, the steps of the torque control method for a four-wheel drive vehicle as described above are implemented.

[0016] The present application determines the torque distribution ratio threshold value according to the current vehicle operating parameters and the distribution ratio mapping relationship when receiving the driving mode switching instruction; determines the target torque distribution ratio according to the current torque distribution ratio and the torque distribution ratio threshold value; and controls the torque of the four-wheel drive vehicle according to the target torque distribution ratio. By processing the distribution ratio during the switching process from two-wheel drive to four-wheel drive, and the torque lost by the torque increment on the new drive shaft during the restricted process will be compensated by another drive shaft, thereby realizing torque filtering for the working condition of the motor gear and the shaft end gear hitting the teeth, so as to avoid the occurrence of the tooth hitting phenomenon. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0019] Figure 1 A schematic diagram of a flow chart of a torque control method for a four-wheel drive vehicle according to a first embodiment of the present invention; Figure 2 A schematic diagram of a platform limit value for the torque distribution ratio provided in the first embodiment of the torque control method for a four-wheel drive vehicle of the present application; Figure 3 A schematic diagram of a flow chart provided for the second embodiment of the torque control method for a four-wheel drive vehicle of the present application; Figure 4 A simplified schematic diagram of the motion relationship between the entire vehicle and the front and rear motor gears and the front and rear axle end gears provided in the second embodiment of the torque control method for a four-wheel drive vehicle of the present application; Figure 5 A schematic diagram of vehicle dynamics analysis in rear-wheel drive mode provided for the second embodiment of the torque control method for a four-wheel drive vehicle of the present application; Figure 6 A schematic diagram of dynamic analysis of the front motor end gear in rear-wheel drive mode provided in Embodiment 2 of the torque control method for a four-wheel drive vehicle of the present application; Figure 7 A schematic diagram of the dynamic analysis of the ABC system in the rear-wheel drive mode provided in the second embodiment of the torque control method for the four-wheel drive vehicle of the present application; Figure 8 A schematic diagram of dynamic analysis of the front motor end gear in a four-wheel drive mode provided in Embodiment 2 of the torque control method for a four-wheel drive vehicle of the present application; Fig. 9A schematic diagram of dynamic analysis when D and ABC start in a four-wheel drive mode provided in Embodiment 2 of the torque control method for a four-wheel drive vehicle of the present application; Fig.10 A schematic diagram of dynamic analysis of the ABC system in a four-wheel drive mode provided in Embodiment 2 of the torque control method for a four-wheel drive vehicle of the present application; Fig.11 A schematic diagram of a brief flow chart of a torque control method for a four-wheel drive vehicle provided in Embodiment 1 of the present application; Fig.12 This is a schematic diagram of the module structure of the torque control device of the four-wheel drive vehicle according to the embodiment of the present application; Fig.13 Schematic diagram of the device structure of the hardware operating environment involved in the torque control method of the four-wheel drive vehicle in the embodiment of the present application.

[0020] The purpose, features and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0021] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.

[0022] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0023] The main solution of the embodiment of the present application is: when a drive mode switching instruction is received, a torque distribution ratio threshold is determined according to current vehicle operating parameters and a distribution ratio mapping relationship; a target torque distribution ratio is determined according to the current torque distribution ratio and the torque distribution ratio threshold; and the torque of the four-wheel drive vehicle is controlled according to the target torque distribution ratio.

[0024] When a four-wheel drive vehicle switches from rear-wheel drive to four-wheel drive, when the front wheel changes from a driven wheel to a driving wheel, if the torque is not well controlled, it is easy to cause a gear knocking shock. However, the front axle's gear knocking shock is not only caused by the torque crossing zero. The reasons for this kind of gear knocking are more complicated. The point of gear knocking is not when the torque crosses zero. Even if the torque has passed zero, gear knocking may still occur. Therefore, how to completely avoid the gear knocking phenomenon when switching from two-wheel drive mode to four-wheel drive mode has become an urgent problem to be solved.

[0025] The present application determines the torque distribution ratio threshold value according to the current vehicle operating parameters and the distribution ratio mapping relationship when receiving the driving mode switching instruction; determines the target torque distribution ratio according to the current torque distribution ratio and the torque distribution ratio threshold value; and controls the torque of the four-wheel drive vehicle according to the target torque distribution ratio. By processing the distribution ratio during the switching process from two-wheel drive to four-wheel drive, and the torque lost by the torque increment on the new drive shaft during the restricted process will be compensated by another drive shaft, thereby realizing torque filtering for the working condition of the motor gear and the shaft end gear hitting the teeth, so as to avoid the occurrence of the tooth hitting phenomenon.

[0026] It should be noted that the execution subject of this embodiment may be a computing service device with data processing, network communication and program running functions, such as a tablet computer, a personal computer, a mobile phone, etc., or a torque control device for a four-wheel drive vehicle that can realize the above functions, etc. The following takes the torque control device for a four-wheel drive vehicle as an example of the execution subject to illustrate this embodiment and the following embodiments.

[0027] Based on this, the present application embodiment provides a torque control method for a four-wheel drive vehicle, referring to Figure 1 , Figure 1 This is a flow chart of a first embodiment of a torque control method for a four-wheel drive vehicle of the present application.

[0028] In this embodiment, the torque control method of the four-wheel drive vehicle includes steps S10 to S30: Step S10, when receiving the driving mode switching instruction, determining the torque distribution ratio threshold value according to the current vehicle operating parameters and the distribution ratio mapping relationship; It should be noted that the drive mode switching instruction refers to the control instruction for switching from two-wheel drive mode to four-wheel drive mode. The current vehicle operating parameters include the total wheel-end torque, the current vehicle speed, and the current ramp angle, etc. The distribution ratio mapping relationship refers to the mapping relationship between the pre-set vehicle operating parameters and the torque distribution ratio. The torque distribution ratio threshold refers to the torque distribution ratio critical value corresponding to the current vehicle operating parameters.

[0029] In the specific implementation, when a control command is received to switch from the two-wheel drive mode to the four-wheel drive mode, the total wheel-end torque, the current vehicle speed and the current ramp angle corresponding to the current vehicle operation are obtained, and then the mapping relationship between the pre-set vehicle operating parameters and the torque distribution ratio is queried to obtain the torque distribution ratio critical value corresponding to the current vehicle operating parameters.

[0030] Step S20, determining a target torque distribution ratio according to the current torque distribution ratio and the torque distribution ratio threshold; It can be understood that the current torque distribution ratio refers to the torque distribution ratio of the vehicle's current operation, and the target torque distribution ratio refers to the final four-wheel drive torque distribution ratio (the ratio of the front wheel torque to the total wheel-end torque).

[0031] In a specific implementation, the torque distribution ratio of the vehicle's current operation is compared with the torque distribution ratio critical value 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 torque distribution ratio critical value corresponding to the current vehicle operating parameters, it indicates that the torque distribution ratio needs to be platform-limited, thereby obtaining the final four-wheel drive torque distribution ratio.

[0032] In a feasible implementation, step S20 may include steps A21 to A23: Step A21, comparing the current torque distribution ratio with the torque distribution ratio threshold to obtain a target comparison result; It can be understood that the target comparison result refers to the comparison result between the current torque distribution ratio and the torque distribution ratio threshold.

[0033] In a specific implementation, the torque distribution ratio of the vehicle's current operation is compared with the torque distribution ratio critical value corresponding to the current vehicle operating parameters, thereby obtaining a comparison result that the torque distribution ratio of the vehicle's current operation is greater than or equal to the torque distribution ratio critical value corresponding to the current vehicle operating parameters, or a comparison result that the torque distribution ratio of the vehicle's current operation is less than the torque distribution ratio critical value corresponding to the current vehicle operating parameters.

[0034] 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, performing limit processing on the current torque distribution ratio to obtain a limit distribution ratio; It can be understood that the limit distribution ratio refers to the torque distribution ratio after platform limit processing.

[0035] In a specific implementation, when the target comparison result is that the torque distribution ratio of the vehicle's current operation is greater than or equal to the torque distribution ratio critical value corresponding to the current vehicle operating parameters, it indicates that the torque distribution ratio needs to be platform limited, and then the torque distribution ratio of the vehicle's current operation is gradient limited, and finally the torque distribution ratio after platform limit processing is obtained.

[0036] Step A23, determining a target torque distribution ratio according to at least one of the limit distribution ratio, a first gradient limit and a second gradient limit, wherein the second gradient limit is greater than the first gradient limit.

[0037] It can be understood that the first gradient limit refers to the torque distribution ratio corresponding to the maximum allowable negative change rate, and the second gradient limit refers to the torque distribution ratio corresponding to the maximum allowable positive change rate.

[0038] In the specific implementation, the torque distribution ratio after platform limit processing is compared with the torque distribution ratio corresponding to the maximum allowable negative change rate and the torque distribution ratio corresponding to the maximum allowable positive change rate, and then gradient limit processing is performed according to the comparison result, and finally the final four-wheel drive torque distribution ratio (the ratio of front wheel torque to total wheel end torque) is obtained.

[0039] In a feasible implementation manner, step A23 may include steps B231 to B233: Step B231, performing difference calculation based on the limit allocation ratio and the adjacent allocation ratio to obtain a target allocation ratio difference; It can be understood that the adjacent distribution ratio refers to the torque distribution ratio at the next moment, and the target distribution ratio difference refers to the difference between the current distribution ratio and the adjacent distribution ratio.

[0040] In the specific implementation, in order to avoid the impact of torque mutation on drivability, it is necessary to perform gradient limiting processing on the torque distribution ratio after platform limit processing, and then obtain the torque distribution ratio at the next moment, and then calculate the difference between the torque distribution ratio after platform limit processing and the torque distribution ratio at the next moment, and finally obtain the target distribution ratio difference.

[0041] Step B232, comparing the target allocation ratio difference with the first gradient limit and the second gradient limit respectively to obtain an allocation ratio difference comparison result; It can be understood 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 and the first gradient limit and the second gradient limit.

[0042] In a specific implementation, the difference rate between the current distribution ratio and the adjacent distribution ratio is compared with the torque distribution ratio corresponding to the maximum allowable negative change rate and the torque distribution ratio corresponding to the maximum allowable positive change rate, and finally the distribution ratio difference comparison result is obtained.

[0043] Step B233, determining a 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.

[0044] It can be understood that, based on the comparison results of different target distribution ratio differences with the first gradient limit and the second gradient limit, at least one of the adjacent distribution ratio, the limit distribution ratio, the first gradient limit and the second gradient limit is selected to calculate the distribution ratio to obtain the final four-wheel drive torque distribution ratio.

[0045] In a feasible implementation manner, step B233 may include steps C2331 to C2333: Step C2331, when the allocation ratio difference comparison result is that the target allocation ratio difference is less than the first gradient limit value, determining the target allocation ratio according to the limit allocation ratio and the first gradient limit value; It can be understood that when the distribution ratio difference comparison result is that the target distribution ratio difference is less than the torque distribution ratio corresponding to the maximum allowable negative change rate, the torque distribution ratio after platform limit processing and the torque distribution ratio corresponding to the maximum allowable negative change rate are summed to obtain the target distribution ratio.

[0046] Step C2332, when the allocation ratio difference comparison result is that the target allocation ratio difference is greater than the second gradient limit, determining the target allocation ratio according to the limit allocation ratio and the second gradient limit; It can be understood that when the distribution ratio difference comparison result is that the target distribution ratio difference is greater than the torque distribution ratio corresponding to the maximum allowable positive change rate, the torque distribution ratio after platform limit processing and the torque distribution ratio corresponding to the maximum allowable positive change rate are summed to obtain the target distribution ratio.

[0047] Step C2333, when the 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, determine the target allocation ratio according to the adjacent allocation ratio.

[0048] It can be understood that when the distribution ratio difference comparison result is that the target distribution ratio difference is greater than or equal to the torque distribution ratio corresponding to the maximum allowable negative change rate and the distribution ratio difference comparison result is that the target distribution ratio difference is less than or equal to the torque distribution ratio corresponding to the maximum allowable positive change rate, the target distribution ratio is obtained according to the torque distribution ratio at the next moment.

[0049] It should be noted that the first step is to determine whether the two-wheel drive to four-wheel drive flag is activated. If the flag is activated at this time, the expected distribution ratio at this time needs to be calculated based on the current Perform platform processing; the second step is to calculate the total wheel end torque T at this time. Whl_total Vehicle speed v and slope angle , query to get the critical value of the distribution ratio ; The third step is when the expected distribution ratio reaches the critical value of the distribution ratio , set the demand allocation ratio to a platform limit. Based on experience, Figure 2 As shown, when the expected distribution ratio K desired Reaching the critical value of distribution ratio After that, the distribution ratio K desried_dealed Need to be limited to +0.025 About 0.15s later, follow the expected distribution ratio K desired ; Step 4, Kdesried_dealed Gradient limiting is required to prevent torque mutation from affecting drivability. According to the discrete control method, 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.

[0050] It is understandable that, in order to avoid gear slapping, most current control methods directly process the torque request at the wheel end, and the vehicle's power response will be limited. Since this embodiment processes the distribution ratio, during the switching process from 2WD to 4WD, the torque lost by the torque increment on the new drive shaft during the limited process will be compensated by another drive shaft. Therefore, when switching between four-wheel drive, the vehicle will not have any power loss or response lag.

[0051] Step S30: controlling the torque of the four-wheel drive vehicle according to the target torque distribution ratio.

[0052] It can be understood that the torque distribution ratio in this embodiment refers to the ratio of the front wheel torque to the total wheel end torque, and the total wheel end torque is then distributed according to the calculated final torque distribution ratio to obtain the front wheel torque and rear wheel torque of the vehicle, that is, the torque of the vehicle switching from two-wheel drive to four-wheel drive is filtered to avoid the occurrence of gear knocking.

[0053] This embodiment determines the torque distribution ratio threshold according to the current vehicle operating parameters and the distribution ratio mapping relationship when receiving the drive mode switching instruction; determines the target torque distribution ratio according to the current torque distribution ratio and the torque distribution ratio threshold; and controls the torque of the four-wheel drive vehicle according to the target torque distribution ratio. By processing the distribution ratio during the switching process from two-wheel drive to four-wheel drive, and the torque lost by the torque increment on the new drive shaft during the restricted process will be compensated by another drive shaft, thereby realizing torque filtering for the working condition of the motor gear and the shaft end gear hitting the teeth, so as to avoid the occurrence of the tooth hitting phenomenon.

[0054] Based on the first embodiment of the present application, in the second embodiment of the present application, the same or similar contents as those in the above-mentioned embodiment 1 can be referred to the above introduction, and will not be repeated in the following. Figure 3 Before step S10, the torque control method of the four-wheel drive vehicle further includes steps S01-S02: Step S01, performing dynamic analysis according to the vehicle driving mode to determine key vehicle parameters; It can be understood that the vehicle driving mode includes a two-wheel drive mode and a four-wheel drive mode, and the vehicle key parameters refer to the vehicle operating parameters that affect the torque distribution ratio, and the vehicle key parameters include the total wheel end torque, the current vehicle speed and the current ramp angle.

[0055] In a specific implementation, dynamic analysis is performed under different vehicle driving modes, and then the vehicle operating parameters affecting the torque distribution ratio, namely the total wheel end torque, the current vehicle speed and the current ramp angle, are determined based on the analysis results.

[0056] In a feasible implementation, step S01 may include steps A011 to A013: Step A011, when the vehicle driving mode is the vehicle rear-wheel drive mode, performing a dynamic analysis on the vehicle to obtain a rear-wheel drive analysis result; It can be understood that when the vehicle driving mode is the vehicle rear-wheel drive mode (two-wheel drive mode), the power of the whole vehicle is only provided by the rear motor of the vehicle. When the rear motor end gear and the system composed of the rear axle shaft end gear and other moving parts come into contact, the rear motor end gear pushes the system composed of the rear axle shaft end gear and other moving parts and the system composed of the front axle shaft end gear and other moving parts to move, and then the system composed of the front axle shaft end gear and other moving parts pushes the front motor end gear to move, so that the whole system moves together. Finally, the dynamic analysis results of the vehicle rear-wheel drive mode are obtained.

[0057] Step A012, when the vehicle driving mode is a four-wheel drive mode, performing a dynamic analysis on the vehicle to obtain a four-wheel drive analysis result; It can be understood that when the vehicle driving mode is the vehicle four-wheel drive mode, both the rear motor end gear and the front motor end gear have the ability to provide power, thereby allowing the entire system to move together, and finally obtaining the dynamic analysis results of the vehicle four-wheel drive mode.

[0058] Step A013, determining key vehicle parameters according to the rear-wheel drive analysis results and the four-wheel drive analysis results.

[0059] In a specific implementation, the dynamic analysis results of the vehicle's rear-wheel drive mode and 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 ramp angle.

[0060] It should be noted that the vehicle's motion model is very complex, especially when it involves internal rotating parts, the dynamic model will be too complex to be physically analyzed. This embodiment uses a simplified model for analysis. The motion relationship between the vehicle and the front and rear motor gears and the front and rear axle end gears is simplified as follows: Figure 4 The form shown. A represents the system composed of the rear axle shaft end gear and other moving parts, B represents the rear motor end gear, C represents the system composed of the front axle shaft end gear and other moving parts, and D represents the front motor end gear. A and C are rigidly connected.

[0061] 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 only provided by B. When B and A come into contact, B pushes A and C to move, and then C pushes D to move. Thus, the entire system moves together. The acceleration of the entire system .like Figure 6 As shown, the force analysis for D is as follows (the resistance on the mutual motion surface between C and D is very small and can be ignored): .like Figure 7 As shown, analyze the ABC system: ,at this time, = = .

[0062] It is understandable that when the rear-wheel drive is switched to four-wheel drive, that is, when both B and D have the ability to provide power, such as Figure 8 As shown in the figure, when D starts to provide power, C and D cannot separate immediately due to the deformation of the non-rigid body. There is still an interaction force between C and D. However, the acceleration of D is still not greater than the acceleration of the entire system, so D still cannot separate from C. And due to the deformation, the interaction force between C and D It is very difficult to analyze. When D and C can be completely separated, there is no interaction between D and ABC system. The dynamic analysis of D and ABC system is as follows: Fig. 9 As shown, At this time, the dynamic analysis of the ABC system is as follows: Fig.10 As shown, ,when >0, D and C will separate, similar to the separation of the gear surface at the front axle motor end and the gear surface at the front axle shaft end. > ,make , , analogizing this simplified model to the vehicle system, when the gear surface at the front axle motor end and the gear surface at the front axle shaft end are separated, the following formula is satisfied:

[0063]

[0064] >

[0065] After simplification, we get:

[0066] +

[0067] =f roll ( v, m, fr) = f slope ( ) =

[0068] in, : angular acceleration of 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, : Total moment of inertia of the P3 motor and the connected gear system, : vehicle acceleration, R: wheel radius, : The remaining mass of the vehicle after removing the P3 motor, : Rotational mass correction factor, : rolling resistance, : Ramp resistance, : Wind resistance.

[0069] It should be understood that through the above analysis, when the vehicle parameters are constant, the vehicle mass m and the frontal area A are constant. The rolling resistance coefficient is affected by the wheel surface environment, and in most cases, the common road surface takes a constant between 0.015 and 0.02. In summary, when the vehicle parameters are constant, the rolling resistance is only related to the vehicle speed, the ramp resistance is only related to the ramp angle, and the wind resistance is only related to the vehicle speed. Based on this formula It can be seen that the condition for whether the front axle motor gear can be separated 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 change in the value of Vehicle speed v and slope angle related.

[0070] Step S02, obtaining a distribution ratio mapping relationship according to the key vehicle parameters and a preset control variable strategy.

[0071] It can be understood that the preset control variable strategy refers to a calibration strategy of a preset control variable.

[0072] In the specific implementation, according to the total wheel end torque, the current vehicle speed and the current ramp angle, a bench or real vehicle test is performed through the control variable method to determine the corresponding total wheel end torque T at each gear engagement. Whl_total , vehicle speed v, slope angle And the torque distribution ratio k, and then generate a mapping relationship of the torque distribution ratio.

[0073] In a feasible implementation, step S02 may include steps A021 to A023: Step A021, performing a working condition simulation according to key vehicle parameters and a preset control variable strategy to obtain a vehicle simulation result; It is understandable that the vehicle simulation results include the total wheel end torque T corresponding to each gear working condition. Whl_total , vehicle speed v, slope angle And the torque distribution ratio k.

[0074] In the specific implementation, according to the total wheel end torque, the current vehicle speed and the current ramp angle, the bench or real vehicle test is carried out through the control variable method to simulate various gear striking conditions, and then the corresponding total wheel end torque T of each gear striking condition is obtained. Whl_total , vehicle speed v, slope angle And the torque distribution ratio k, which is the vehicle simulation result.

[0075] Step A022, determining the vehicle operating parameters and torque distribution ratio corresponding to the preset working condition according to the vehicle simulation result; It is understood that the preset working condition refers to the preset gear working 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-engaging condition.

[0076] Step A023, generating a distribution ratio mapping relationship according to the vehicle operating parameters corresponding to the preset operating condition and the torque distribution ratio.

[0077] In the specific implementation, each gear punching condition is combined 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 a mapping relationship of the torque distribution ratio.

[0078] It should be noted that in this embodiment, the condition for whether the front axle motor gear can be separated from the shaft end gear surface when switching from the two-wheel drive state to the four-wheel drive state only needs to consider the four-wheel drive distribution ratio k. The critical value of the distribution ratio is only related to the total wheel end torque T Whl_total , vehicle speed v and slope angle Through bench or real vehicle testing, the corresponding wheel end total torque T can be determined for each tooth punching by using the control variable method. Whl_total , vehicle speed v and slope angle , and the distribution ratio k. Different wheel end total torque T Whl_total , vehicle speed v and slope angle The corresponding distribution ratio critical value . =Map(T Whl_total ).

[0079] This embodiment performs a dynamic analysis based on the vehicle driving mode to determine the key parameters of the vehicle; and obtains the distribution ratio mapping relationship based on the key parameters of the vehicle and the preset control variable strategy. By performing a dynamic analysis on the rear-wheel drive mode and the four-wheel drive mode of the vehicle respectively, the parameters affecting the torque distribution coefficient are determined, and then the torque distribution ratio mapping relationship is generated through the control variable strategy, and finally the distribution ratio is processed to ensure that there will be no power loss and response hysteresis when switching between four-wheel drives.

[0080] For example, in order to help understand the implementation process of the torque control method of the four-wheel drive vehicle obtained by combining this embodiment with the above-mentioned embodiment 1, please refer to Fig.11 , Fig.11 A brief flow chart of a torque control method for a four-wheel drive vehicle is provided. Specifically, in the first step, it is necessary to determine whether the two-wheel drive to four-wheel drive flag is activated. If the flag is activated at this time, the expected distribution ratio at this time needs to be calculated according to the current Perform platform processing; the second step is to calculate the total wheel end torque T at this time. Whl_total Vehicle speed v and slope angle , query to get the critical value of the distribution ratio ; The third step is when the expected distribution ratio reaches the critical value of the distribution ratio , set the demand allocation ratio to a platform limit. Based on experience, Figure 2 As shown, when the expected distribution ratio K desired Reaching the critical value of distribution ratio After that, the distribution ratio K desried_dealed Need to be limited to +0.025 About 0.15s later, follow the expected distribution ratio K desired ; Step 4, K desried_dealedGradient limiting is required to prevent torque mutation from affecting drivability. According to the discrete control method, 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.

[0081] It should be noted that the above examples are only used to understand the present application and do not constitute a limitation on the torque control method of the four-wheel drive vehicle of the present application. More simple transformations based on this technical concept are all within the scope of protection of the present application.

[0082] The present application also provides a torque control device for a four-wheel drive vehicle, please refer to Fig.12 , the torque control device of the four-wheel drive vehicle comprises: The processing module 10 is used to determine the torque distribution ratio threshold value according to the current vehicle operating parameters and the distribution ratio mapping relationship when receiving the driving mode switching instruction; The processing module 10 is further used to determine a target torque distribution ratio according to the current torque distribution ratio and the torque distribution ratio threshold; The control module 20 is used to control the torque of the four-wheel drive vehicle according to the target torque distribution ratio.

[0083] Optionally, the processing module 10 is further used for: Comparing the current torque distribution ratio with the torque distribution ratio threshold to obtain a 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, performing limit processing on the current torque distribution ratio to obtain a limit distribution ratio; The target torque distribution ratio is determined according to at least one of the limit distribution ratio, a first gradient limit value, and a second gradient limit value, the second gradient limit value being greater than the first gradient limit value.

[0084] Optionally, the processing module 10 is further used for: Calculate the difference between the limit allocation ratio and the adjacent allocation ratio to obtain a target allocation ratio difference; Comparing the target allocation ratio difference with the first gradient limit value and the second gradient limit value respectively to obtain an allocation ratio difference comparison result; A target allocation ratio is determined according to 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.

[0085] Optionally, the processing module 10 is further used for: When the allocation ratio difference comparison result is that the target allocation ratio difference is less than the first gradient limit value, determining the target allocation ratio according to the limit allocation ratio and the first gradient limit value; When the allocation ratio difference comparison result is that the target allocation ratio difference is greater than the second gradient limit, determining the target allocation ratio according to the limit allocation ratio and the second gradient limit; When the allocation ratio difference comparison result is that the target allocation ratio difference is greater than or equal to the first gradient limit value and the target allocation ratio difference is less than or equal to the second gradient limit value, the target allocation ratio is determined according to the adjacent allocation ratios.

[0086] Optionally, the processing module 10 is further used for: Conduct dynamic analysis based on vehicle driving modes to determine key vehicle parameters; The allocation ratio mapping relationship is obtained according to the key vehicle parameters and the preset control variable strategy.

[0087] Optionally, the processing module 10 is further used for: When the vehicle driving mode is a rear-wheel drive mode, a dynamic analysis is performed on the vehicle to obtain a rear-wheel drive analysis result; When the vehicle driving mode is a four-wheel drive mode, a dynamic analysis is performed on the vehicle to obtain a four-wheel drive analysis result; The key parameters of the vehicle are determined according to the rear-wheel drive analysis results and the four-wheel drive analysis results.

[0088] Optionally, the processing module 10 is further used for: Perform working condition simulation based on key vehicle parameters and preset control variable strategies to obtain vehicle simulation results; Determining vehicle operating parameters and torque distribution ratios corresponding to a preset operating condition according to the vehicle simulation results; A distribution ratio mapping relationship is generated according to the vehicle operating parameters corresponding to the preset operating condition and the torque distribution ratio.

[0089] The torque control device for a four-wheel drive vehicle provided by the present application adopts the torque control method for a four-wheel drive vehicle in the above-mentioned embodiment, and can solve the technical problem of how to completely avoid the gear-snapping phenomenon when switching from a two-wheel drive mode to a four-wheel drive mode. Compared with the prior art, the beneficial effects of the torque control device for a four-wheel drive vehicle provided by the present application are the same as the beneficial effects of the torque control method for a four-wheel drive vehicle provided by the above-mentioned embodiment, and the other technical features of the torque control device for a four-wheel drive vehicle are the same as the features disclosed in the above-mentioned embodiment method, and are not described in detail here.

[0090] The present application provides a torque control device for a four-wheel drive vehicle, and 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 so that the at least one processor can execute the torque control method for the four-wheel drive vehicle in the above-mentioned embodiment one.

[0091] Reference below Fig.13 , which shows a schematic diagram of the structure of a torque control device for a four-wheel drive vehicle suitable for implementing the embodiment of the present application. The torque control device for a four-wheel drive vehicle in the embodiment of the present application may include but is not limited to mobile terminals such as mobile phones, laptop computers, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Descriptions), PMPs (Portable Media Players), vehicle-mounted terminals (such as vehicle-mounted navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, etc. Fig.13 The torque control device of the four-wheel drive vehicle shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0092] like Fig.13As shown, the torque control device of the four-wheel drive vehicle may include a processing device 1001 (such as 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: Read Only Memory) 1002 or a program loaded from a storage device 1003 to a random access memory (RAM: Random Access Memory) 1004. In RAM1004, various programs and data required for the operation of the torque control device of the four-wheel drive vehicle are also stored. The processing device 1001, ROM1002 and RAM1004 are connected to each other through a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Typically, the following systems can be connected to the I / O interface 1006: input devices 1007 including, for example, a touch screen, a touchpad, a keyboard, a mouse, an image sensor, a microphone, an accelerometer, a gyroscope, etc.; output devices 1008 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; storage devices 1003 including, for example, a magnetic tape, a hard disk, etc.; and communication devices 1009. The communication device 1009 can allow the torque control device of the four-wheel drive vehicle to communicate with other devices wirelessly or by wire to exchange data. Although the figure shows a torque control device of a four-wheel drive vehicle with various systems, it should be understood that it is not required to implement or have all the systems shown. More or fewer systems may be implemented or have alternatively.

[0093] In particular, according to the embodiments disclosed in the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments disclosed in the present application include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through a communication device, or installed from a storage device 1003, or installed from a ROM 1002. When the computer program is executed by the processing device 1001, the above-mentioned functions defined in the method of the embodiment disclosed in the present application are executed.

[0094] The torque control device for a four-wheel drive vehicle provided by the present application adopts the torque control method for a four-wheel drive vehicle in the above embodiment, and can solve the technical problem of how to completely avoid the gear-snapping phenomenon when switching from a two-wheel drive mode to a four-wheel drive mode. Compared with the prior art, the beneficial effects of the torque control device for a four-wheel drive vehicle provided by the present application are the same as the beneficial effects of the torque control method for a four-wheel drive vehicle provided by the above embodiment, and the other technical features of the torque control device for a four-wheel drive vehicle are the same as the features disclosed in the method of the previous embodiment, and are not described in detail here.

[0095] It should be understood that the various parts disclosed in this application can be implemented by 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 one or more embodiments or examples in a suitable manner.

[0096] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0097] The present application provides a computer-readable storage medium having computer-readable program instructions (ie, computer programs) stored thereon, the computer-readable program instructions being used to execute the torque control method for a four-wheel drive vehicle in the above-mentioned embodiment.

[0098] The computer-readable storage medium provided in the present application may be, for example, a USB flash drive, but is not limited to electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, systems or devices, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM: Random Access Memory), a read-only memory (ROM: Read Only Memory), an erasable programmable read-only memory (EPROM: Erasable Programmable Read Only Memory or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM: CD-Read Only Memory), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program, which may be used by or in combination with an instruction execution system, system or device. The program code contained on the computer-readable storage medium may be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (Radio Frequency: Radio Frequency), etc., or any suitable combination of the above.

[0099] The computer-readable storage medium may be included in the torque control device of the four-wheel drive vehicle; or may exist independently without being assembled into the torque control device of the four-wheel drive vehicle.

[0100] The above-mentioned computer-readable storage medium carries one or more programs. When the above-mentioned one or more programs are executed by the torque control device of the four-wheel drive vehicle, the torque control device of the four-wheel drive vehicle: when receiving a drive mode switching instruction, determines the torque distribution ratio threshold value according to the current vehicle operating parameters and the distribution ratio mapping relationship; determines the target torque distribution ratio according to the current torque distribution ratio and the torque distribution ratio threshold value; and controls the torque of the four-wheel drive vehicle according to the target torque distribution ratio.

[0101] Computer program code for performing the operations of the present application may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0102] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0103] The modules involved in the embodiments described in this application may be implemented by software or hardware, wherein the name of the module does not constitute a limitation on the unit itself in some cases.

[0104] The readable storage medium provided in the present application is a computer-readable storage medium, which stores computer-readable program instructions (i.e., computer programs) for executing the torque control method for the above-mentioned four-wheel drive vehicle, and can solve the technical problem of how to completely avoid the gear-snapping phenomenon when switching from a two-wheel drive mode to a four-wheel drive mode. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in the present application are the same as the beneficial effects of the torque control method for the four-wheel drive vehicle provided in the above-mentioned embodiment, and will not be elaborated here.

[0105] The present application also provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the steps of the torque control method for a four-wheel drive vehicle as described above are implemented.

[0106] The computer program product provided by the present application can solve the technical problem of how to completely avoid the gear-snagging phenomenon when switching from a two-wheel drive mode to a four-wheel drive mode. Compared with the prior art, the beneficial effects of the computer program product provided by the present application are the same as the beneficial effects of the torque control method for a four-wheel drive vehicle provided by the above embodiment, and will not be elaborated here.

[0107] The above descriptions are only some embodiments of the present application, and are not intended to limit the patent scope of the present application. All equivalent structural changes made using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect applications in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A torque control method for a four-wheel drive vehicle, characterized in that: The torque control method of the four-wheel drive vehicle comprises: When receiving a driving mode switching instruction, determining a torque distribution ratio threshold value according to current vehicle operating parameters and a distribution ratio mapping relationship; determining a target torque distribution ratio according to 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.

2. The method according to claim 1, characterized in that The step of determining the target torque distribution ratio according to the current torque distribution ratio and the torque distribution ratio threshold comprises: Comparing the current torque distribution ratio with the torque distribution ratio threshold to obtain a 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, performing limit processing on the current torque distribution ratio to obtain a limit distribution ratio; The target torque distribution ratio is determined according to at least one of the limit distribution ratio, a first gradient limit value, and a second gradient limit value, the second gradient limit value being greater than the first gradient limit value.

3. The method according to claim 2, characterized in that The step of determining the target torque distribution ratio according to at least one of the limit distribution ratio, the first gradient limit and the second gradient limit comprises: Calculate the difference between the limit allocation ratio and the adjacent allocation ratio to obtain a target allocation ratio difference; Comparing the target allocation ratio difference with the first gradient limit value and the second gradient limit value respectively to obtain an allocation ratio difference comparison result; A target allocation ratio is determined according to 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.

4. The method according to claim 3, characterized in that The step of determining the target allocation ratio according to 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 comprises: When the allocation ratio difference comparison result is that the target allocation ratio difference is less than the first gradient limit value, determining the target allocation ratio according to the limit allocation ratio and the first gradient limit value; When the allocation ratio difference comparison result is that the target allocation ratio difference is greater than the second gradient limit, determining the target allocation ratio according to the limit allocation ratio and the second gradient limit; When the allocation ratio difference comparison result is that the target allocation ratio difference is greater than or equal to the first gradient limit value and the target allocation ratio difference is less than or equal to the second gradient limit value, the target allocation ratio is determined according to the adjacent allocation ratios.

5. The method according to claim 1, characterized in that Before the step of determining the torque distribution ratio threshold according to the current vehicle operating parameters and the distribution ratio mapping relationship when the driving mode switching instruction is received, the method further includes: Conduct dynamic analysis based on vehicle driving modes to determine key vehicle parameters; The allocation ratio mapping relationship is obtained according to the key vehicle parameters and the preset control variable strategy.

6. The method according to claim 5, characterized in that The step of performing dynamic analysis according to the vehicle driving mode to determine the key parameters of the vehicle includes: When the vehicle driving mode is a rear-wheel drive mode, a dynamic analysis is performed on the vehicle to obtain a rear-wheel drive analysis result; When the vehicle driving mode is a four-wheel drive mode, a dynamic analysis is performed on the vehicle to obtain a four-wheel drive analysis result; The key parameters of the vehicle are determined according to the rear-wheel drive analysis results and the four-wheel drive analysis results.

7. The method according to claim 5, characterized in that The step of obtaining the allocation ratio mapping relationship according to the vehicle key parameters and the preset control variable strategy includes: Perform working condition simulation based on key vehicle parameters and preset control variable strategies to obtain vehicle simulation results; Determining vehicle operating parameters and torque distribution ratios corresponding to a preset operating condition according to the vehicle simulation results; A distribution ratio mapping relationship is generated according to the vehicle operating parameters corresponding to the preset operating condition and the torque distribution ratio.

8. A torque control device for a four-wheel drive vehicle, characterized in that: The device comprises: A processing module, configured to determine a torque distribution ratio threshold value according to current vehicle operating parameters and a distribution ratio mapping relationship when receiving a driving mode switching instruction; The processing module is further used to determine a target torque distribution ratio according to the current torque distribution ratio and the torque distribution ratio threshold; A control module is used to control the torque of the four-wheel drive vehicle according to the target torque distribution ratio.

9. A torque control device for a four-wheel drive vehicle, characterized in that: The device comprises: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the torque control method for a four-wheel drive vehicle according to any one of claims 1 to 7.

10. 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, the steps of the torque control method for a four-wheel drive vehicle as described in any one of claims 1 to 7 are implemented.

Images