CN107813813B

CN107813813B - Automobile and torque control method and system of sand mode of automobile

Info

Publication number: CN107813813B
Application number: CN201610823016.1A
Authority: CN
Inventors: 周小伟; 李桂忠; 石明川; 王震
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2016-09-13
Filing date: 2016-09-13
Publication date: 2020-07-10
Anticipated expiration: 2036-09-13
Also published as: CN107813813A

Abstract

The invention discloses an automobile and a torque control method and system of a sand mode of the automobile, wherein the control method comprises the following steps: after the automobile enters a sand mode, acquiring the current speed, the steering wheel angle and the gradient of the current road where the automobile is located; and adjusting the torque of the front axle and the rear axle of the automobile according to the current speed, the steering wheel angle and the current gradient of the road. The control method provided by the embodiment of the invention can be used for actively controlling the automobile according to the current running state of the automobile so as to reasonably distribute the torque of the front shaft and the rear shaft, thereby fully exerting the driving force, reducing the slip ratio and improving the off-road performance of the automobile under extreme working conditions such as desert and the like.

Description

Automobile and torque control method and system of sand mode of automobile

Technical Field

The invention relates to the technical field of automobiles, in particular to a torque control method of an automobile sand ground mode, a torque control system of the automobile sand ground mode and an automobile.

Background

In the related art, the sand mode of the vehicle limits the torque output of the whole vehicle by controlling the slip rate. Specifically, power is distributed to the front wheel and the rear wheel through the central differential lock and the differential, and then the power is distributed to the high-attachment wheels through the participation of the braking system, so that the purpose of getting rid of difficulties is achieved.

Among them, the sand mode four-wheel drive central differential is generally divided into two main categories:

one is a locking differential. Usually, a locking differential can be selected manually to achieve the purpose of fixedly connecting the front shaft and the rear shaft, and the distribution ratio of the front shaft and the rear shaft is fixed to be 50: 50. The advantages are that: the distribution proportion is fixed, the sliding is avoided, and the device is reliable and durable. The disadvantages are as follows: the vehicle is not suitable for running at high speed and paving road surfaces.

The other is a limited slip differential. The front-rear axle distribution ratio can be dynamically adjusted depending on the slip, but the distribution ratio generally has an upper limit value, and the front-rear distribution ratio limit value is generally 75:25 or 25: 75. The advantages are that: the power distribution is smooth and the use is convenient. The disadvantages are as follows: high requirements on a braking system and difficult matching.

However, the limited slip differential and the locking differential both use a single power source to transmit power to the front and rear wheel ends through the transmission shaft, the central differential and the differential lock, so that independent control of the front and rear axles cannot be realized, the characteristic that the front and rear axles cannot be actively adjusted exists, and the front and rear axles can only be adjusted in a fixed proportion or passively adjusted under the condition of slipping, so that the limited slip differential and the locking differential are difficult to get out of the ground under the working conditions of variable terrain and large resistance (such as in desert).

Disclosure of Invention

The present invention is directed to solving, at least to some extent, one of the technical problems in the art described above.

Therefore, a first objective of the present invention is to provide a torque control method for a sand mode of an automobile, which actively controls the automobile according to the current operating state of the automobile to reasonably distribute the torques of the front and rear axles, so as to fully exert the driving force, reduce the slip ratio and improve the off-road performance of the automobile under extreme conditions such as desert.

The second purpose of the invention is to provide a torque control system of a sand ground mode of the automobile.

A third object of the invention is to provide a motor vehicle.

In order to achieve the above object, an embodiment of a first aspect of the present invention provides a torque control method for a sand mode of an automobile, including the following steps: after the automobile enters a sand mode, acquiring the current speed, the steering wheel angle and the gradient of the current road where the automobile is located; and adjusting the torque of the front axle and the rear axle of the automobile according to the current speed, the steering wheel angle and the gradient of the current road.

According to the torque control method of the automobile sand ground mode, after the automobile enters the sand ground mode, the current speed and the steering wheel angle of the automobile and the gradient of the current road where the automobile is located are obtained, and then the torque of the front shaft and the rear shaft of the automobile is adjusted according to the current speed, the steering wheel angle and the gradient of the current road.

In order to achieve the above object, a second aspect of the present invention provides a torque control system for a sand mode of a vehicle, comprising: the acquisition module is used for acquiring the current speed and the steering wheel angle of the automobile and the gradient of the current road where the automobile is located after the automobile enters a sand mode; and the controller is used for adjusting the torque of the front axle and the rear axle of the automobile according to the current speed, the steering wheel angle and the gradient of the current road.

According to the torque control system of the sand ground mode of the automobile, after the automobile enters the sand ground mode, the current speed and the steering wheel angle of the automobile and the gradient of the current road where the automobile is located are obtained through the obtaining module, the torque of the front shaft and the rear shaft of the automobile is adjusted through the controller according to the current speed, the steering wheel angle and the gradient of the current road, and the system actively controls the automobile according to the current running state of the automobile to reasonably distribute the torque of the front shaft and the rear shaft, so that the driving force can be fully exerted under extreme working conditions such as desert and the like, the slip rate is reduced, and the cross-country performance of the automobile is improved.

Further, a third aspect of the present invention provides a vehicle, including the vehicle sand mode torque control system according to the above embodiments of the present invention.

According to the automobile provided by the embodiment of the invention, the torque control system in the automobile sand ground mode is used for actively controlling the automobile according to the current running state of the automobile so as to reasonably distribute the torques of the front axle and the rear axle, so that the driving force can be fully exerted under extreme working conditions such as desert and the like, the slip rate is reduced, and the cross-country performance of the automobile is improved.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic diagram of an electric four-wheel drive configuration of an automobile in accordance with one embodiment of the present invention;

FIG. 2 is a flow chart of a method of torque control in a sand mode of a vehicle according to one embodiment of the present invention;

FIG. 3 is a schematic diagram of information interaction of a torque control method for a sand mode of a vehicle according to an embodiment of the invention;

FIG. 4 is a flowchart of the torque control method step S2 for the sand mode of the vehicle according to one embodiment of the invention;

FIG. 5 is a flow chart of a method of torque control in a vehicle sand mode according to one specific example of the present disclosure;

FIG. 6 is a flowchart of a torque control method for a sand mode of a vehicle according to another embodiment of the present invention

FIG. 7 is a block diagram of a torque control system for a sand mode of a vehicle according to an embodiment of the present invention;

FIG. 8 is a block diagram of a torque control system for a sand mode of a vehicle according to an embodiment of the present invention;

FIG. 9 is a block diagram of a vehicle sand mode torque control system according to a specific example of the present invention;

FIG. 10 is a block diagram of a torque control system for a vehicle sand mode according to another specific example of the present invention;

fig. 11 is a block diagram of a torque control system of a sand mode of a vehicle according to another embodiment of the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

The following describes a torque control method, a system and a vehicle in a sand mode of the vehicle according to an embodiment of the present invention with reference to the drawings.

First, in the embodiment of the present invention, the automobile is a hybrid automobile, and the model structure thereof is as shown in fig. 1, and an electric four-wheel drive structure is adopted. The hybrid vehicle realizes four-wheel drive torque control by a motor controller (not shown in fig. 1), drive motors (i.e., a front motor and a rear motor shown in fig. 1), an in-cylinder direct injection 2.0TI engine, a DCT (Dual Clutch Transmission), a wet Clutch Transmission (not shown in fig. 1), a reduction gear (not shown in fig. 1), a differential lock, and the like. The front shaft is in a control output mode of an engine and a front motor, and the power is strong; the rear axle is driven by a single motor (i.e., the rear motor shown in fig. 1).

FIG. 2 is a flow chart of a torque control method for a sand mode of a vehicle according to an embodiment of the invention. As shown in fig. 2, the torque control method in the sand mode of the vehicle includes the steps of:

and S1, acquiring the current speed and the steering wheel angle of the automobile and the gradient of the current road where the automobile is located after the automobile enters the sand mode.

In one embodiment of the present invention, the automobile may be provided with a plurality of terrain mode (such as sand mode, urban mode, suburban mode, etc.) selection buttons on the main driving side, and the buttons may be physical buttons, that is, the user may trigger the buttons by pressing, pulling up, etc. to select the corresponding terrain mode; the button may also be an inductive button, i.e. the user may trigger the button by clicking, touching, etc. to select the corresponding terrain mode.

Specifically, the speed of the vehicle may be collected by a speed sensor disposed at one or more wheels, the steering wheel angle may be collected by a steering angle sensor disposed at a steering wheel or a steering wheel column, and the gradient of the current road on which the vehicle is disposed may be collected by a gradient sensor disposed on the vehicle.

And S2, adjusting the front and rear axle torque of the automobile according to the current vehicle speed, the steering wheel angle and the current road gradient.

In one embodiment of the present invention, when the user selects the sand mode, the motor controller in the vehicle will assume the sand mode torque control method and the transmission controller will also assume the sand mode control method. The motor controller E controls the torque output of the driving motor to be transmitted to the gearbox controller, and the gearbox controller selects the optimal gear to transmit the torque to the wheels according to the running condition of the automobile.

Specifically, as shown in fig. 3, the mode switch module is an operation interface for interacting with a user, and the user may select the sand mode through the operation interface. When the automobile enters a sand environment, a user can select a sand mode, at the moment, a sand mode signal is transmitted to the motor controller, the power battery manager monitors and manages the power battery shown in the figure 1, and signals such as the chargeable and dischargeable power, the SOC (State of Charge) and the like of the power battery are sent to the motor controller; the vehicle body stability controller can transmit the acquired signals of vehicle speed, wheel speed and the like to the motor controller; the motor controller can acquire signals such as braking, an accelerator, gradient, steering wheel rotation angle and the like. The obtaining module 100 arranged in the vehicle body controller can further obtain signals of the current vehicle speed of the vehicle, the gradient of the current road where the vehicle is located, the steering wheel angle and the like, and the controller 200 arranged in the vehicle body controller can control the front motor and the rear motor shown in fig. 2 to output corresponding torques according to the signals of the current vehicle speed, the gradient of the current road, the steering wheel angle and the like.

It can be understood that signal interaction can be carried out between the gearbox controller and the motor controller, when a user selects a sand mode through a mode switch, the gearbox controller needs to judge the gear state of the gearbox controller so as to judge whether the automobile can enter the sand mode or not and give feedback to the motor controller, wherein when the gear is normal, the automobile is judged to enter the sand mode and feed the feedback to the motor controller.

Meanwhile, after the automobile enters the sand mode, the gearbox controller executes a gear shifting strategy of the sand mode; the combination meter can display the terrain mode information of the location of the automobile so that a user can judge the current terrain mode of the whole automobile, and therefore the best terrain mode can be selected according to different terrains, and safe and reliable running of the automobile is facilitated.

Therefore, after the automobile enters a sand mode, the current speed, the steering wheel angle and the gradient of the current road where the automobile is located are obtained, and then the front and rear axle torques of the automobile are adjusted according to the current speed, the steering wheel angle and the gradient of the current road.

In an embodiment of the present invention, as shown in fig. 4, the step S2 further includes:

and S21, judging whether the current vehicle speed is less than the first vehicle speed.

And S22, if the current vehicle speed is greater than or equal to the first vehicle speed, controlling the vehicle to enter a gradient control mode so as to adjust the torque of the front axle and the rear axle of the vehicle according to the current vehicle speed and the gradient of the current road.

Specifically, when the vehicle enters the grade control mode, it is determined whether the vehicle is ascending or descending. If the automobile is in a downhill, the torque of the front axle and the rear axle of the automobile can be distributed according to different speeds; if the vehicle is ascending, the front axle torque of the vehicle may be distributed in combination with the current vehicle speed according to the grade of the current road.

And S23, if the current vehicle speed is less than the first vehicle speed, controlling the vehicle to enter a steering control mode to adjust the torque of the front and rear shafts of the vehicle according to the steering wheel angle.

Specifically, when the automobile enters a steering control mode, it is determined whether the steering wheel is now steered. If the steering wheel is turned to be small at the moment, such as 0-45 degrees, namely when the automobile does not steer, controlling the torque distribution proportion of the front axle and the rear axle of the automobile to be a fixed value; if the steering wheel angle is large at this time, for example, 145 ° to 540 °, that is, the vehicle is turning, the front-rear axle distribution ratio of the vehicle may be controlled according to the difference in the steering wheel angle, that is, the front-rear axle distribution ratio of the vehicle may be changed at this time, wherein the changed distribution ratio may be linearly changed according to the steering wheel angle.

Specifically, as shown in fig. 5, the method for controlling torque in a sand mode of an automobile according to an embodiment of the present invention may specifically include the following steps:

s301, judging whether the current vehicle speed is less than the first vehicle speed.

S302, if the current vehicle speed is greater than or equal to the first vehicle speed, whether the gradient of the current road is smaller than the first gradient is judged.

S303, if the gradient of the current road is smaller than the first gradient, determining that the automobile runs on a downhill, and judging whether the current automobile speed is larger than a second automobile speed, wherein the second automobile speed is larger than the first automobile speed.

S304, if the current vehicle speed is less than or equal to the second vehicle speed, adjusting the front-rear axle torque distribution ratio of the vehicle according to the formula K-a 1V + b1, where a1, b1 are constants, V is the current vehicle speed, K is the front-rear axle torque distribution ratio of the vehicle corresponding to V, when V is the first vehicle speed V1, the front-rear axle torque distribution ratio of the corresponding vehicle is the first ratio K1, when V is the second vehicle speed V2, the front-rear axle torque distribution ratio of the corresponding vehicle is the second ratio K2, and the first ratio K1 is greater than the second ratio K2.

The front-rear axle torque distribution ratio is front axle torque/rear axle torque.

Specifically, K1 ═ a1V1+ b1, and K2 ═ a1V2+ b1, then a1 ═ (K1-K2)/(V1-V2), b1 ═ K1V2-K2V1)/(V1-V2 can be obtained. And then the torque distribution proportion of the front axle and the rear axle of the automobile can be adjusted according to the difference of the current speed V.

Wherein, K1, K2, V1 and V2 can be fixed values obtained by a plurality of tests and big data analysis.

S305, if the current vehicle speed is greater than the second vehicle speed, further judging whether the current vehicle speed is greater than a third vehicle speed, wherein the third vehicle speed is greater than the second vehicle speed.

And S306, if the current vehicle speed is less than or equal to a third vehicle speed, adjusting the front-rear axle torque distribution proportion of the automobile according to the formula of a2V + b2, wherein a2 and b2 are constants, when V is the second vehicle speed, the front-rear axle torque distribution proportion of the corresponding automobile is a second proportion, when V is the third vehicle speed, the front-rear axle torque distribution proportion of the corresponding automobile is a third proportion, and the second proportion is less than the third proportion.

Similarly, a2 ═ K2-K3)/(V2-V3) and b2 ═ K2V3-K3V2)/(V2-V3 can be calculated, and the torque distribution ratio of the front axle and the rear axle of the automobile can be adjusted according to the difference of the current vehicle speed V.

Wherein, K2, K3, V2 and V3 can be fixed values obtained by a plurality of tests and big data analysis.

S307, if the current vehicle speed is greater than the third vehicle speed, whether the current vehicle speed is greater than a fourth vehicle speed is further judged, wherein the fourth vehicle speed is greater than the third vehicle speed.

And S308, if the current vehicle speed is less than or equal to a fourth vehicle speed, adjusting the front-rear axle torque distribution proportion of the automobile according to the formula of a3V + b3, wherein when a3 and b3 are constants, V is a third vehicle speed, the front-rear axle torque distribution proportion of the corresponding automobile is a third proportion, and when V is the fourth vehicle speed, the front-rear axle torque distribution proportion of the corresponding automobile is a fourth proportion, and the third proportion is less than the fourth proportion.

Similarly, a3 ═ K3-K4)/(V3-V4) and b3 ═ K3V4-K4V3)/(V3-V4 can be calculated, and the torque distribution ratio of the front axle and the rear axle of the automobile can be adjusted according to the difference of the current vehicle speed V.

Wherein, K3, K4, V3 and V4 can be fixed values obtained by a plurality of tests and big data analysis.

S309, if the current vehicle speed is larger than the fourth vehicle speed, controlling the torque distribution proportion of the front axle and the rear axle of the automobile to be a fourth proportion.

And S310, if the gradient of the current road is greater than or equal to the first gradient, determining that the automobile runs uphill, and further judging whether the gradient of the current road is greater than a second gradient, wherein the second gradient is greater than the first gradient.

And S311, if the gradient of the current road is less than or equal to the second gradient, controlling the torque of the front axle of the automobile to be less than or equal to the first torque.

S312, if the gradient of the current road is larger than the second gradient, whether the current vehicle speed is larger than a fifth vehicle speed is judged, wherein the fifth vehicle speed is larger than the first vehicle speed.

Specifically, if the gradient of the current road is greater than or equal to the first gradient, indicating that the vehicle is in an uphill driving state, the front axle torque of the vehicle may be controlled according to the gradient (i.e., the second gradient) and the current vehicle speed (i.e., which is compared with the fifth vehicle speed).

And S313, if the current vehicle speed is less than or equal to the fifth vehicle speed, adjusting the torque of the front axle of the vehicle according to the current vehicle speed, wherein the torque of the front axle of the vehicle corresponding to the current vehicle speed is greater than the second torque and less than the first torque.

Specifically, when the vehicle is on an uphill slope, the slope is greater than the second slope, and the vehicle speed is less than or equal to the fifth vehicle speed, in order to better ensure the driving performance of the vehicle, before the vehicle leaves a factory, a plurality of tests may be performed to obtain corresponding values of the vehicle speed and the front axle torque, and the corresponding values may be stored in a form of a table, where a linear corresponding relationship exists between the vehicle speed and the front axle torque, and the front axle torque corresponding to the greater the vehicle speed is, is smaller. And then when the automobile runs in a sand mode, the slope is larger than the second slope, and the automobile speed is smaller than or equal to a fifth automobile speed, the motor controller can query the stored table according to the current automobile speed to obtain the corresponding front axle torque, and control the front axle to run by the queried torque.

And S314, if the current vehicle speed is greater than the fifth vehicle speed, controlling the torque of the front axle of the automobile to be less than or equal to the second torque.

In an embodiment of the present invention, the first torque and the second torque may be obtained according to experimental tests.

Specifically, if the gradient of the current road is less than or equal to the second gradient, the torque of the front axle of the vehicle is controlled to be less than or equal to the first torque. And if the gradient of the current road is greater than the second gradient and the current vehicle speed is less than or equal to the fifth vehicle speed, linearly adjusting the torque of the front axle of the vehicle according to the current vehicle speed, wherein the torque of the front axle of the vehicle is greater than the second torque range and less than the first torque range. And if the gradient of the current road is greater than the second gradient and the current vehicle speed is greater than the fifth vehicle speed, controlling the torque of the front axle of the automobile to be less than the second torque.

And S315, if the current vehicle speed is less than the first vehicle speed, judging whether the steering wheel steering angle is greater than a preset steering angle.

And S316, if the steering wheel rotating angle is larger than the preset rotating angle, controlling the torque distribution proportion of the front shaft and the rear shaft of the automobile to be a fifth proportion, wherein the fifth proportion is smaller than the first proportion.

Specifically, the vehicle is in a turning state when the turning angle of the steering wheel is greater than a preset turning angle, which may be 90 °.

In the embodiment of the present invention, the fifth ratio is a variable that may be linearly changed according to the steering wheel angle, i.e., linearly decreased as the steering wheel angle increases.

Optionally, the value range of the fifth ratio may be 0.538 to 9.

Since the starting points for the low speed and the medium and high speed, and the straight start and the turning start are different, the distribution ratio to be adopted is adjusted to a certain degree. For the steering situation, the torque distribution ratio of the rear axle of the vehicle increases, the fifth ratio decreases, and the fifth ratio decreases as the steering angle increases. It is understood that there is no direct logical relationship between the fifth ratio and the second, third and fourth ratios.

In an embodiment of the invention, the values of the second ratio, the third ratio and the fourth ratio may range from 0.538 to 9, and the first ratio may be smaller than the third ratio.

And S317, if the steering wheel rotating angle is smaller than or equal to the preset rotating angle, controlling the torque distribution proportion of the front shaft and the rear shaft of the automobile to be a first proportion. In the embodiment of the invention, the first proportion is a fixed value, the value range can be 0.538-9, and the first proportion is larger than the fifth proportion.

The first vehicle speed, the second vehicle speed, …, and the fifth vehicle speed are vehicle speeds at the time of power control of the vehicle, that is, the engine and the front and rear motors shown in fig. 2 have a control relationship with respect to the front and rear wheels of the vehicle. The first vehicle speed, the second vehicle speed, the … and the fifth vehicle speed can be set according to empirical values or numerical values after big data processing, the first vehicle speed, the second vehicle speed, the third vehicle speed and the fourth vehicle speed correspond to torque distribution of a small slope, and the fifth vehicle speed corresponds to torque distribution of a big slope.

In an embodiment of the invention, when the automobile is in a sliding state after entering the desert mode, the sliding feedback function can be controlled according to the sliding speed, so as to achieve the purpose of energy saving.

Specifically, as shown in fig. 6, if the current vehicle speed is a coasting vehicle speed, it is determined whether the coasting vehicle speed is less than a sixth vehicle speed, where the coasting vehicle speed may include a neutral coasting vehicle speed and a geared coasting vehicle speed; if the sliding vehicle speed is less than the sixth vehicle speed, controlling the vehicle to cancel sliding feedback; if the coasting vehicle speed is greater than or equal to the sixth vehicle speed, further judging whether the coasting vehicle speed is less than the seventh vehicle speed, wherein the sixth vehicle speed is less than the seventh vehicle speed; if the coasting speed is less than the seventh speed, controlling the automobile to perform coasting feedback according to a formula Q-mV + n, wherein m and n are constants, V is the coasting speed, and Q is a coasting feedback rate corresponding to V, when V is the sixth speed, the corresponding Q is 0, and when V is the seventh speed, the corresponding Q is a coasting feedback rate threshold value; and if the coasting vehicle speed is greater than or equal to the seventh vehicle speed, controlling the vehicle to perform coasting feedback by using a coasting feedback rate threshold value.

Specifically, if 0 mV6+ n and Qmax mV7+ n are used, m Qmax/(V7-V6) and n QmaxV6/(V6-V7) can be calculated. The Qmax, V6, and V7 may be fixed values measured through experiments, so that the vehicle may be controlled to perform coasting feedback at corresponding feedback rates according to different coasting vehicle speeds.

The coasting feedback refers to an electric quantity feedback function of the vehicle. The control of the vehicle for coasting feedback according to the formula Q ═ mV + n is a way to recover the coasting feedback function, that is, the feedback rate of the coasting feedback function may have a linear relationship with the coasting vehicle speed, and the feedback rate increases linearly with the increase of the coasting vehicle speed.

Specifically, when the coasting vehicle speed is greater than the sixth vehicle speed and less than the seventh vehicle speed, the feedback rate of the coasting feedback may be linearly increased as the coasting vehicle speed increases, or linearly decreased as the coasting vehicle speed decreases. And when the sliding vehicle speed is greater than or equal to the seventh vehicle speed, the vehicle recovers sliding feedback to be normal, namely the feedback rate of the sliding feedback reaches the maximum.

It can be understood that when the automobile slides, the motor recovers kinetic energy and converts the kinetic energy into electric energy, so that the aim of saving energy can be fulfilled.

To sum up, according to the torque control method of the sand ground mode of the automobile provided by the embodiment of the invention, after the automobile enters the sand ground mode, the current speed and the steering wheel angle of the automobile and the gradient of the current road where the automobile is located are obtained, and then the torque of the front axle and the rear axle of the automobile is adjusted according to the current speed, the steering wheel angle and the gradient of the current road. In addition, when the automobile slides and runs, energy feedback control is carried out according to the sliding speed, so that the aim of energy conservation can be fulfilled, the reasonable distribution of oil and electricity of the automobile is facilitated, and the running mileage of the automobile in a desert environment is improved. The method achieves the corresponding purpose through software control without adding any hardware, and saves the production cost.

Based on the torque control method of the vehicle sand ground mode of the embodiment, the invention provides a torque control system of the vehicle sand ground mode.

Fig. 7 is a block diagram of a torque control system in a sand mode of a vehicle according to an embodiment of the present invention. As shown in fig. 7, the torque control system for the sand mode of the vehicle includes an acquisition module 100 and a controller 200.

The obtaining module 100 is configured to obtain a current speed and a steering wheel angle of the vehicle and a gradient of a current road where the vehicle is located after the vehicle enters the sand mode. The controller 200 is used to adjust the front and rear axle torque of the vehicle according to the current vehicle speed, the steering wheel angle, and the current road grade.

Therefore, after the automobile enters a sand mode, the acquisition module acquires the current speed and the steering wheel angle of the automobile and the gradient of the current road where the automobile is located, and then the controller adjusts the front and rear axle torques of the automobile according to the current speed, the steering wheel angle and the gradient of the current road.

In one embodiment of the present invention, as shown in fig. 8, the controller 200 may include a first determination module 210, a first control module 220, and a second control module 230.

The first judging module 210 is configured to judge whether the current vehicle speed is less than a first vehicle speed; the first control module 220 is used for controlling the automobile to enter a gradient control mode when the current speed is greater than or equal to a first speed so as to adjust the torque of the front axle and the rear axle of the automobile according to the current speed and the gradient of the current road; the second control module 230 is configured to control the vehicle to enter a steering control mode when the current vehicle speed is less than the first vehicle speed, so as to adjust a front-rear axle torque of the vehicle according to a steering wheel angle.

Further, as shown in fig. 9, the first control module 220 may include a first judging unit 1, a second judging unit 2, a first control unit 3, a third judging unit 4, a second control unit 5, a fourth judging unit 6, a third control unit 7, a fourth control unit 8, a fifth judging unit 9, a fifth control unit 10, a sixth judging unit 11, a sixth control unit 12, and a seventh control unit 13.

The first judging unit 1 is used for judging whether the gradient of the current road is smaller than a first gradient; the second judging unit 2 is used for judging that the automobile does not run downhill when the gradient of the current road is smaller than the first gradient, and judging whether the current speed is larger than a second speed, wherein the second speed is larger than the first speed; the first control unit 3 is configured to adjust a front-rear axle torque distribution ratio of the vehicle according to a formula K of a1V + b1 when the current vehicle speed is less than or equal to a second vehicle speed, where a1 and b1 are constants, V is the current vehicle speed, K is the front-rear axle torque distribution ratio of the vehicle corresponding to V, when V is the first vehicle speed, the front-rear axle torque distribution ratio of the corresponding vehicle is a first ratio, and when V is the second vehicle speed, the front-rear axle torque distribution ratio of the corresponding vehicle is a second ratio, and the first ratio is greater than the second ratio; the third judging unit 4 is used for judging whether the current vehicle speed is greater than a third vehicle speed when the current vehicle speed is greater than the second vehicle speed, wherein the third vehicle speed is greater than the second vehicle speed; the second control unit 5 is configured to adjust the front-rear axle torque distribution ratio of the vehicle according to the equation K2V + b2 when the current vehicle speed is less than or equal to a third vehicle speed, where a2 and b2 are constants, V is the second vehicle speed, the corresponding front-rear axle torque distribution ratio of the vehicle is a second ratio, V is the third vehicle speed, the corresponding front-rear axle torque distribution ratio of the vehicle is a third ratio, and the second ratio is less than the third ratio. The fourth judging unit 6 is configured to judge whether the current vehicle speed is greater than a fourth vehicle speed when the current vehicle speed is greater than the third vehicle speed, where the fourth vehicle speed is greater than the third vehicle speed; the third control unit 7 is configured to adjust a front-rear axle torque distribution ratio of the automobile according to a formula K ═ a3V + b3 when the current vehicle speed is less than or equal to a fourth vehicle speed, where a3 and b3 are constants, V is the third vehicle speed, the corresponding front-rear axle torque distribution ratio of the automobile is a third ratio, V is the fourth vehicle speed, the corresponding front-rear axle torque distribution ratio of the automobile is a fourth ratio, and the third ratio is less than the fourth ratio; the fourth control unit 8 is used for controlling the torque distribution proportion of the front axle and the rear axle of the automobile to be a fourth proportion when the current speed is higher than the fourth speed. The fifth judging module 9 is configured to determine that the vehicle is traveling uphill when the gradient of the current road is greater than or equal to the first gradient, and judge whether the gradient of the current road is greater than a second gradient, where the second gradient is greater than the first gradient; the fifth control unit 10 is used for controlling the torque of the front axle of the automobile to be less than or equal to the first torque when the gradient of the current road is less than or equal to the second gradient; the sixth judging unit 11 is configured to judge whether the current vehicle speed is greater than a fifth vehicle speed when the gradient of the current road is greater than the second gradient, where the fifth vehicle speed is greater than the first vehicle speed; the sixth control unit 12 is configured to adjust a torque of a front axle of the vehicle according to the current vehicle speed when the current vehicle speed is less than or equal to a fifth vehicle speed, where the front axle torque of the vehicle corresponding to the current vehicle speed is greater than the second torque and less than the first torque; the seventh control unit 13 is adapted to controlling the torque of the front axle of the vehicle to be less than or equal to the second torque when the current vehicle speed is greater than the fifth vehicle speed.

As shown in fig. 10, the second control module 230 includes a seventh judging unit 14, an eighth controlling unit 15, and a ninth controlling unit 16.

The seventh judging unit 14 is configured to judge whether a steering wheel angle is greater than a preset angle; the eighth control unit 15 is configured to control a torque distribution ratio of the front and rear axles of the automobile to be a fifth ratio when the steering wheel angle is greater than the preset steering angle, where the fifth ratio is smaller than the first ratio; the ninth control unit 16 is configured to control the torque distribution ratio of the front and rear axles of the automobile to a first ratio when the steering wheel angle is less than or equal to a preset angle.

For the purpose of energy saving, in an embodiment of the present invention, as shown in fig. 11, the controller 200 further includes a second determination module 240, a third control module 250, a third determination module 260, a fourth control module 270, and a fifth control module 280.

The second judging module 240 is configured to judge whether the coasting vehicle speed is less than a sixth vehicle speed when the current vehicle speed is the coasting vehicle speed, where the coasting vehicle speed includes a neutral coasting vehicle speed and a geared coasting vehicle speed; the third control module 250 is used for controlling the automobile to cancel sliding feedback when the sliding speed is less than the sixth speed; the third judging module 260 is configured to judge whether the coasting vehicle speed is less than a seventh vehicle speed when the coasting vehicle speed is greater than or equal to a sixth vehicle speed, where the sixth vehicle speed is less than the seventh vehicle speed; the fourth control module 270 is configured to control the vehicle to perform coasting feedback according to a formula Q ═ mV + n when the coasting vehicle speed is less than the seventh vehicle speed, where m and n are constants, V is the coasting vehicle speed, Q is a coasting feedback rate corresponding to V, when V is the sixth vehicle speed, the corresponding Q is 0, and when V is the seventh vehicle speed, the corresponding Q is a coasting feedback rate threshold; the fifth control module 280 is configured to control the vehicle to coast back at the coasting back rate threshold when the coasting vehicle speed is greater than or equal to the seventh vehicle speed.

It should be noted that the specific implementation of the torque control system in the sand mode of the vehicle according to the embodiment of the present invention is the same as the specific implementation of the torque control method in the sand mode of the vehicle according to the above embodiment of the present invention, and for reducing redundancy, no further description is provided here.

To sum up, according to the torque control system of the sand ground mode of the automobile provided by the embodiment of the invention, after the automobile enters the sand ground mode, the acquisition module acquires the current speed and the steering wheel angle of the automobile and the gradient of the current road where the automobile is located, and then the controller adjusts the torque of the front axle and the rear axle of the automobile according to the current speed, the steering wheel angle and the gradient of the current road. In addition, when the automobile slides and runs, energy feedback control is carried out according to the sliding speed, so that the aim of energy conservation can be fulfilled, the reasonable distribution of oil and electricity of the automobile is facilitated, and the running mileage of the automobile in a desert environment is improved. And the system achieves the corresponding purpose through software control without adding any hardware, thereby saving the production cost.

Further, the invention provides a vehicle, which comprises the vehicle sand mode torque control system of the embodiment of the invention.

In an embodiment of the invention, the vehicle is an electric four-wheel drive vehicle.

According to the automobile provided by the embodiment of the invention, the torque control system of the automobile sand ground mode is used for actively controlling the automobile so as to reasonably distribute the torques of the front axle and the rear axle, so that the driving force can be fully exerted under extreme working conditions such as desert and the like, the slip rate is reduced, and the off-road performance of the automobile is improved. In addition, when the automobile slides and runs, energy feedback control is carried out according to the sliding speed, so that the aim of energy conservation can be fulfilled, the reasonable distribution of oil and electricity of the automobile is facilitated, and the running mileage of the automobile in a desert environment is improved. And the system achieves the corresponding purpose through software control without adding any hardware, thereby saving the production cost.

In addition, other structures and functions of the automobile according to the embodiment of the present invention are known to those skilled in the art, and are not described herein in detail in order to reduce redundancy.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims

1. A torque control method for a sand mode of an automobile is characterized by comprising the following steps:

after the automobile enters a sand mode, acquiring the current speed, the steering wheel angle and the gradient of the current road where the automobile is located;

adjusting a front-rear axle torque of the automobile according to the current vehicle speed, the steering wheel angle and the gradient of the current road, wherein the adjusting the front-rear axle torque of the automobile according to the current vehicle speed, the steering wheel angle and the gradient of the current road comprises:

judging whether the current vehicle speed is less than a first vehicle speed,

controlling the automobile to enter a gradient control mode to adjust the front and rear axle torques of the automobile according to the current vehicle speed and the gradient of the current road if the current vehicle speed is greater than or equal to the first vehicle speed,

and if the current vehicle speed is less than the first vehicle speed, controlling the vehicle to enter a steering control mode so as to adjust the torque of the front shaft and the rear shaft of the vehicle according to the steering wheel angle.

2. The torque control method for a sand mode of a vehicle according to claim 1, wherein said adjusting the front and rear axle torque of the vehicle according to the current vehicle speed, the gradient of the current road comprises:

judging whether the gradient of the current road is smaller than a first gradient or not;

if the gradient of the current road is smaller than the first gradient, determining that the automobile runs on a downhill, and judging whether the current automobile speed is larger than a second automobile speed, wherein the second automobile speed is larger than the first automobile speed;

if the current vehicle speed is less than or equal to the second vehicle speed, adjusting the front-rear axle torque distribution proportion of the vehicle according to the formula of a1V + b1, wherein a1 and b1 are constants, V is the current vehicle speed, K is the front-rear axle torque distribution proportion of the vehicle corresponding to V, when V is the first vehicle speed, the front-rear axle torque distribution proportion of the corresponding vehicle is a first proportion, when V is the second vehicle speed, the front-rear axle torque distribution proportion of the corresponding vehicle is a second proportion, and the first proportion is smaller than the second proportion;

if the current vehicle speed is greater than the second vehicle speed, further judging whether the current vehicle speed is greater than a third vehicle speed, wherein the third vehicle speed is greater than the second vehicle speed;

if the current vehicle speed is less than or equal to the third vehicle speed, adjusting the front-rear axle torque distribution proportion of the automobile according to the formula of a2V + b2, wherein when a2 and b2 are constants, and V is the third vehicle speed, the corresponding front-rear axle torque distribution proportion of the automobile is a third proportion, and the second proportion is less than the third proportion.

3. The torque control method for sand mode of vehicle according to claim 2, further comprising:

if the current vehicle speed is greater than the third vehicle speed, further judging whether the current vehicle speed is greater than a fourth vehicle speed, wherein the fourth vehicle speed is greater than the third vehicle speed;

if the current vehicle speed is less than or equal to the fourth vehicle speed, adjusting the front-rear axle torque distribution proportion of the vehicle according to the formula of a3V + b3, wherein when a3 and b3 are constants, and when V is the fourth vehicle speed, the corresponding front-rear axle torque distribution proportion of the vehicle is a fourth proportion, and the third proportion is less than the fourth proportion;

and if the current vehicle speed is greater than the fourth vehicle speed, controlling the torque distribution proportion of the front axle and the rear axle of the automobile to be a fourth proportion.

4. The torque control method for sand mode of vehicle according to claim 2, further comprising:

if the gradient of the current road is greater than or equal to the first gradient, determining that the automobile runs uphill, and further judging whether the gradient of the current road is greater than a second gradient, wherein the second gradient is greater than the first gradient;

controlling a torque of a front axle of the automobile to be less than or equal to a first torque if the gradient of the current road is less than or equal to the second gradient;

if the gradient of the current road is greater than the second gradient, judging whether the current vehicle speed is greater than a fifth vehicle speed, wherein the fifth vehicle speed is greater than the first vehicle speed;

if the current vehicle speed is less than or equal to the fifth vehicle speed, adjusting the torque of a front axle of the automobile according to the current vehicle speed, wherein the front axle torque of the automobile corresponding to the current vehicle speed is greater than a second torque and less than the first torque;

and if the current vehicle speed is greater than the fifth vehicle speed, controlling the torque of the front axle of the automobile to be less than or equal to the second torque.

5. The torque control method for a sand mode of a vehicle according to claim 1, wherein said adjusting the front and rear axle torques of the vehicle according to the steering wheel angle comprises:

judging whether the steering wheel corner is larger than a preset corner or not;

if the steering wheel rotating angle is larger than the preset rotating angle, controlling the torque distribution proportion of the front shaft and the rear shaft of the automobile to be a fifth proportion;

and if the steering wheel rotating angle is smaller than or equal to the preset rotating angle, controlling the torque distribution proportion of the front shaft and the rear shaft of the automobile to be a first proportion, wherein the fifth proportion is smaller than the first proportion.

6. The torque control method for sand mode of vehicle according to claim 1, further comprising:

if the current vehicle speed is a coasting vehicle speed, judging whether the coasting vehicle speed is less than a sixth vehicle speed, wherein the coasting vehicle speed comprises a neutral coasting vehicle speed and a geared coasting vehicle speed;

if the sliding vehicle speed is less than the sixth vehicle speed, controlling the vehicle to cancel sliding feedback;

if the coasting vehicle speed is greater than or equal to the sixth vehicle speed, further judging whether the coasting vehicle speed is less than a seventh vehicle speed, wherein the sixth vehicle speed is less than the seventh vehicle speed;

if the coasting vehicle speed is less than the seventh vehicle speed, controlling the vehicle to coast and feed back according to a formula Q (mV + n), wherein m and n are constants, V is the coasting vehicle speed, Q is a coasting feedback rate corresponding to V, and when V is the sixth vehicle speed, the corresponding Q is 0;

and if the coasting vehicle speed is greater than or equal to the seventh vehicle speed, controlling the automobile to perform coasting feedback by the coasting feedback rate threshold value.

7. A vehicle sand mode torque control system, comprising:

the acquisition module is used for acquiring the current speed and the steering wheel angle of the automobile and the gradient of the current road where the automobile is located after the automobile enters a sand mode;

the controller is used for adjusting the torque of the front axle and the rear axle of the automobile according to the current speed, the steering wheel angle and the gradient of the current road;

wherein the controller includes:

a first judging module for judging whether the current vehicle speed is less than a first vehicle speed,

a first control module for controlling the automobile to enter a gradient control mode when the current speed is greater than or equal to the first speed so as to adjust the torque of the front and rear axles of the automobile according to the current speed and the gradient of the current road,

and the second control module is used for controlling the automobile to enter a steering control mode when the current speed is less than the first speed so as to adjust the torque of the front shaft and the rear shaft of the automobile according to the steering wheel angle.

8. The automotive sand mode torque control system of claim 7, wherein the first control module comprises:

the first judging unit is used for judging whether the gradient of the current road is smaller than a first gradient or not;

the second judging unit is used for determining that the automobile runs on a downhill when the gradient of the current road is smaller than the first gradient, and judging whether the current automobile speed is larger than a second automobile speed, wherein the second automobile speed is larger than the first automobile speed;

a first control unit, configured to adjust a front-rear axle torque distribution ratio of the vehicle according to a formula K of a1V + b1 when the current vehicle speed is less than or equal to the second vehicle speed, where a1 and b1 are constants, V is the current vehicle speed, K is the front-rear axle torque distribution ratio of the vehicle corresponding to V, when V is the first vehicle speed, the corresponding front-rear axle torque distribution ratio of the vehicle is a first ratio, when V is the second vehicle speed, the corresponding front-rear axle torque distribution ratio of the vehicle is a second ratio, and the first ratio is less than the second ratio;

the third judging unit is used for judging whether the current vehicle speed is greater than a third vehicle speed when the current vehicle speed is greater than the second vehicle speed, wherein the third vehicle speed is greater than the second vehicle speed;

and a second control unit, configured to adjust the front-rear axle torque distribution ratio of the automobile to switch from the second ratio to a third ratio according to a formula K2V + b2 when the current vehicle speed is less than or equal to the third vehicle speed, where a2 and b2 are constants, V is the third vehicle speed, the corresponding front-rear axle torque distribution ratio of the automobile is the third ratio, and the second ratio is less than the third ratio.

9. The automotive sand mode torque control system of claim 8, wherein the first control module further comprises:

the fourth judging unit is used for judging whether the current vehicle speed is greater than a fourth vehicle speed when the current vehicle speed is greater than the third vehicle speed, wherein the fourth vehicle speed is greater than the third vehicle speed;

a third control unit, configured to adjust a front-rear axle torque distribution ratio of the automobile according to a formula of a3V + b3 when the current vehicle speed is less than or equal to the fourth vehicle speed, where a3 and b3 are constants, V is the fourth vehicle speed, the corresponding front-rear axle torque distribution ratio of the automobile is a fourth ratio, and the third ratio is less than the fourth ratio;

and the fourth control unit is used for controlling the torque distribution proportion of the front axle and the rear axle of the automobile to be a fourth proportion when the current speed is greater than the fourth speed.

10. The automotive sand mode torque control system of claim 8, wherein the first control module further comprises:

the fifth judging module is used for determining that the automobile runs on an uphill slope when the gradient of the current road is greater than or equal to the first gradient, and judging whether the gradient of the current road is greater than a second gradient, wherein the second gradient is greater than the first gradient;

a fifth control unit for controlling a torque of a front axle of the automobile to be less than or equal to a first torque when the gradient of the current road is less than or equal to the second gradient;

a sixth determining unit, configured to determine whether the current vehicle speed is greater than a fifth vehicle speed when the gradient of the current road is greater than the second gradient, where the fifth vehicle speed is greater than the first vehicle speed;

a sixth control unit, configured to adjust a torque of a front axle of the automobile according to the current vehicle speed when the current vehicle speed is less than or equal to the fifth vehicle speed, where the front axle torque of the automobile corresponding to the current vehicle speed is greater than the second torque and less than the first torque;

and the seventh control unit is used for controlling the torque of the front axle of the automobile to be less than or equal to the second torque when the current vehicle speed is greater than the fifth vehicle speed.

11. The automotive sand mode torque control system of claim 7, wherein the second control module comprises:

a seventh judging unit, configured to judge whether the steering wheel angle is greater than a preset angle;

the eighth control unit is used for controlling the torque distribution proportion of the front shaft and the rear shaft of the automobile to be a fifth proportion when the steering wheel rotating angle is larger than the preset rotating angle;

and the tenth control unit is used for controlling the torque distribution proportion of the front shaft and the rear shaft of the automobile to be a first proportion when the steering wheel angle is smaller than or equal to the preset steering angle, wherein the fifth proportion is smaller than the first proportion.

12. The automotive sand mode torque control system of claim 7, wherein the controller further comprises:

the second judgment module is used for judging whether the sliding vehicle speed is less than a sixth vehicle speed when the current vehicle speed is the sliding vehicle speed, wherein the sliding vehicle speed comprises a neutral sliding vehicle speed and a geared sliding vehicle speed;

the third control module is used for controlling the automobile to cancel sliding feedback when the sliding automobile speed is less than the sixth automobile speed;

the third judging module is used for judging whether the coasting vehicle speed is less than a seventh vehicle speed when the coasting vehicle speed is greater than or equal to the sixth vehicle speed, wherein the sixth vehicle speed is less than the seventh vehicle speed;

the fourth control module is used for controlling the automobile to perform coasting feedback according to a formula Q-mV + n when the coasting automobile speed is less than the seventh automobile speed, wherein m and n are constants, V is the coasting automobile speed, Q is a coasting feedback rate corresponding to V, and when V is the sixth automobile speed, the corresponding Q is 0;

and the fifth control module is used for controlling the automobile to perform coasting feedback by the coasting feedback rate threshold value when the coasting automobile speed is greater than or equal to the seventh automobile speed.

13. A vehicle comprising a sand mode torque control system of a vehicle according to any one of claims 7-12.