Control method of four-wheel-drive vehicle, vehicle, controller and storage medium

Abstract

The invention relates to a control method of a four-wheel-drive vehicle, the vehicle, a controller and a storage medium. The control method comprises the following steps: acquiring driving road information and / or a driving mode of the four-wheel-drive vehicle; according to the running road information and / or the driving mode, the rear-drive gears of the four-wheel-drive vehicle are controlled, and under the different gears, a rear-axle drive motor of the four-wheel-drive vehicle outputs different torques. According to the control method of the four-wheel-drive vehicle, the vehicle, the controller and the storage medium, the output torque of the rear axle driving motor can be automatically controlled by achieving automatic gear switching, the dynamic property and the handling stability of the whole vehicle are improved, the four-wheel-drive vehicle better meets the driving requirements of special driving roads, and the driving experience of the four-wheel-drive vehicle is improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of vehicle control, and in particular, to a control method for a four-wheel drive vehicle, a vehicle, a controller, and a storage medium. Background Art

[0002] With the rapid development of new energy vehicles, hybrid vehicles have also developed. Consumers' demands for the power configuration and performance of hybrid vehicles are getting higher and higher, and four-wheel drive systems are gradually applied to hybrid vehicles.

[0003] Compared with traditional two-wheel drive vehicles, four-wheel drive vehicles have better power performance and handling stability, and can be better applied to hybrid vehicles. Summary of the Invention

[0004] The purpose of the present disclosure is to provide a control method for a four-wheel drive vehicle, a vehicle, a controller, and a storage medium. The control method for the four-wheel drive vehicle, the vehicle, the controller, and the storage medium can control the output torque of the rear axle drive motor through gear shifting, thereby improving the overall vehicle power performance and handling stability, enabling the four-wheel drive vehicle to better meet the driving requirements of special driving roads, and enhancing the driving experience of the four-wheel drive vehicle.

[0005] To achieve the above purpose, in a first aspect, the present disclosure provides a control method for a four-wheel drive vehicle, and the control method includes:

[0006] Obtain the driving road information and / or driving mode of the four-wheel drive vehicle;

[0007] According to the driving road information and / or the driving mode, control the gear of the rear drive of the four-wheel drive vehicle, wherein, in different gears, the rear axle drive motor of the four-wheel drive vehicle outputs different torques.

[0008] Optionally, the gears of the rear drive of the four-wheel drive vehicle include: a first gear, a second gear, and a third gear;

[0009] The rear axle drive motor does not output torque in the first gear, and the torque output by the rear axle drive motor in the second gear is less than the torque output by the rear axle drive motor in the third gear.

[0010] Optionally, the driving road information is used to characterize the type of the driving road of the four-wheel drive vehicle. According to the driving road information, controlling the gear of the rear drive of the four-wheel drive vehicle includes:

[0011] If the driving road type belongs to the target driving road type, determine the target gear from the second gear and the third gear, and control the gear of the rear drive of the four-wheel drive vehicle to be the target gear;

[0012] Among them, the torque output by the rear-axle drive motor in the second gear is less than the torque output by the rear-axle drive motor in the third gear.

[0013] Optionally, determining the target gear from the second gear and the third gear includes:

[0014] If the target driving road type is snow or mud, the second gear is determined as the target gear;

[0015] If the target driving road type is any one of sand, mountain and rock, the third gear is determined as the target gear.

[0016] Optionally, controlling the gear of the rear drive of the four-wheel drive vehicle according to the driving mode includes:

[0017] If the driving mode is the sport mode, the second gear is determined as the target gear, and the torque output by the rear-axle drive motor in the second gear is less than the preset torque.

[0018] Optionally, the driving road information is used to characterize the driving road type of the four-wheel drive vehicle. Controlling the gear of the rear drive of the four-wheel drive vehicle according to the driving road information and the driving mode includes:

[0019] If the driving road type does not belong to the target driving road type, and the driving mode is the energy-saving mode or the standard driving mode, a target gear is determined from the first gear and the second gear, and the gear of the rear drive of the four-wheel drive vehicle is controlled to be the target gear;

[0020] The rear-axle drive motor does not output torque in the first gear, and the torque output by the rear-axle drive motor in the second gear is less than the preset torque.

[0021] Optionally, the control method further includes:

[0022] Determining the first total vehicle electric drive loss power of the four-wheel drive vehicle in the first gear;

[0023] Determining the second total vehicle electric drive loss power of the four-wheel drive vehicle in the second gear;

[0024] Determining the target gear from the first gear and the second gear includes:

[0025] Determining the target gear from the first gear and the second gear according to the first total vehicle electric drive loss power and the second total vehicle electric drive loss power.

[0026] Optionally, determining the first total vehicle electric drive loss power of the four-wheel drive vehicle in the first gear includes:

[0027] Determine the first vehicle electric drive loss power according to the front axle information and the required torque of the vehicle motor drive. The front axle information includes: the rotational speed of the front axle drive motor, the efficiency of the front axle drive motor, and the front axle reduction ratio.

[0028] Optionally, the determining the second vehicle electric drive loss power of the four-wheel drive vehicle in the second gear includes:

[0029] Determine the second vehicle electric drive loss power according to the front axle information, the rear axle information, the torque demand ratio, and the required torque of the vehicle motor drive. The front axle information includes: the rotational speed of the front axle drive motor, the efficiency of the front axle drive motor, and the front axle reduction ratio. The rear axle information includes: the rotational speed of the rear axle drive motor, the efficiency of the rear axle drive motor, and the rear axle reduction ratio. The torque demand ratio is the ratio of the torque allocated to the front axle drive motor to the required torque of the vehicle motor drive.

[0030] Optionally, the determining the target gear from the first gear and the second gear according to the first vehicle electric drive loss power and the second vehicle electric drive loss power includes:

[0031] If the first vehicle electric drive loss power is greater than the second vehicle electric drive loss power, determine the second gear as the target gear;

[0032] If the first vehicle electric drive loss power is less than or equal to the second vehicle electric drive loss power, determine the first gear as the target gear.

[0033] Optionally, the determining the target gear from the first gear and the second gear according to the first vehicle electric drive loss power and the second vehicle electric drive loss power includes:

[0034] Determine the target gear from the first gear and the second gear according to the first vehicle electric drive loss power, the second vehicle electric drive loss power, the maximum output torque of the front axle drive motor, and the required torque of the vehicle motor drive.

[0035] Optionally, the determining the target gear from the first gear and the second gear according to the first vehicle electric drive loss power, the second vehicle electric drive loss power, the maximum output torque of the front axle drive motor, and the required torque of the vehicle motor drive includes:

[0036] If the first vehicle electric drive loss power is less than or equal to the second vehicle electric drive loss power, and the required torque of the vehicle motor drive and the maximum output torque of the front axle drive motor satisfy a preset relationship, determine the first gear as the target gear;

[0037] If the first vehicle electric drive loss power is greater than the second vehicle electric drive loss power, and the vehicle motor drive demand torque and the maximum output torque of the front axle drive motor do not satisfy the preset relationship, determine the second gear as the target gear.

[0038] Optionally, the preset relationship is any one of the following:

[0039] The vehicle motor drive demand torque is less than or equal to the maximum output torque of the front axle drive motor;

[0040] The vehicle motor drive demand torque is less than or equal to the difference between the maximum output torque of the front axle drive motor and the preset torque, and the preset torque is the torque required for the drive motor to switch.

[0041] Optionally, the driving road information is used to characterize the driving road type of the four-wheel drive vehicle. According to the driving road information and the driving mode, controlling the gear of the rear drive of the four-wheel drive vehicle includes:

[0042] If the driving road type does not belong to the target driving road type and the driving mode is the sport mode, determine the second gear as the target gear and control the gear of the rear drive of the four-wheel drive vehicle to be the target gear, and the torque output by the rear axle drive motor in the second gear is less than the preset torque.

[0043] Optionally, obtaining the driving road information and / or driving mode of the four-wheel drive vehicle includes:

[0044] Obtain the vehicle state information of the four-wheel drive vehicle;

[0045] Obtain the first information input by the user, where the first information includes at least one of demand driving mode information, demand driving road information, and demand torque information;

[0046] Obtain the second information collected by the information collection device, where the second information includes driving road images and / or driving road types;

[0047] Determine the driving road information and / or the driving mode according to at least one of the vehicle state information, the first information, and the second information.

[0048] Optionally, determining the driving road information and / or the driving mode according to at least one of the vehicle state information, the first information, and the second information includes:

[0049] Determine the driving road information according to the driving road image, the driving road type, the demand driving road information, and the demand torque;

[0050] Determine the driving mode according to the required driving mode and the required torque.

[0051] In a second aspect, the present disclosure provides a controller, including:

[0052] A memory on which a computer program is stored;

[0053] A processor configured to execute the computer program in the memory, so that the controller executes the control method for the four-wheel drive vehicle described in the first aspect.

[0054] In a third aspect, the present disclosure provides a vehicle, including: the controller described in the second aspect.

[0055] In a fourth aspect, the present disclosure provides a computer-readable storage medium, on which computer program instructions are stored, and when the program instructions are executed by a processor, the control method for the four-wheel drive vehicle described in the first aspect is implemented.

[0056] Through the above technical solutions, on the basis of increasing the gears of the rear drive of the four-wheel drive vehicle, the shift control of the four-wheel drive vehicle is correspondingly increased, and the gears of the rear axle motor are automatically controlled according to the road on which the vehicle travels and / or the driving mode, so that the handling stability of the whole vehicle can be improved, and the problem of slow switching response caused by the driver's manual operation can be reduced. In addition, at different gears, the rear axle drive motor can output different torques, so that the power performance of the whole vehicle can be improved, enabling the four-wheel drive vehicle to better meet the driving requirements of special driving roads and enhancing the driving experience of the four-wheel drive vehicle.

[0057] Other features and advantages of the present disclosure will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The drawings are used to provide a further understanding of the present disclosure, and constitute a part of the specification, and are used to explain the present disclosure together with the following specific implementation manners, but do not constitute a limitation to the present disclosure. In the drawings:

[0059] Figure 1 is a flowchart of a control method for a four-wheel drive vehicle shown according to an exemplary embodiment.

[0060] Figure 2 is a schematic diagram of a hybrid system architecture shown according to an exemplary embodiment.

[0061] Figure 3 is a control flowchart of a four-wheel drive vehicle shown according to an exemplary embodiment.

[0062] Figure 4 is a schematic diagram of the relationship between vehicle speed and torque shown according to an exemplary embodiment.

[0063] Figure 5 The figure is a block diagram of a control device for a four-wheel drive vehicle according to an exemplary embodiment.

[0064] Figure 6 It is a schematic functional block diagram of a vehicle according to an exemplary embodiment. DETAILED DESCRIPTION

[0065] The following describes the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0066] In the present disclosure, unless otherwise specified, directional words such as "up, down, left, right, front, back", etc. are used only to facilitate the description of the present disclosure and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present disclosure.

[0067] As mentioned in the background art, four-wheel drive vehicles have better power and operational stability and are well suited for hybrid vehicles.

[0068] First, while four-wheel drive vehicles offer significant improvements in power and handling stability compared to traditional two-wheel drive vehicles, they still suffer from a disadvantage in terms of economy. Secondly, the electric motor is typically connected to the drive wheels via a fixed-ratio reducer. While this generally meets user needs on ordinary roads without special terrain, it fails to meet the high-torque power and maneuverability requirements for all-terrain, off-road, and escape situations. Furthermore, when the vehicle enters special terrain mode, the traditional drive mode is primarily manually switched by the driver. Due to the complex road conditions, manual switching by the driver is slow to respond and can easily lead to dangerous distractions.

[0069] Therefore, the rear axle motor of a hybrid four-wheel drive vehicle in the related art is connected to the drive wheels only through a fixed-ratio reducer. That is, the rear axle motor in the related art typically corresponds to only one drive gear, making the rear axle motor's output torque unadjustable. Furthermore, in low-power operating conditions, such as those on ordinary urban roads, if the rear axle motor has little or no torque distribution, it will lead to low operating efficiency, drag torque (torque generated by the rear wheels driving the motor), and power loss. Furthermore, in all-terrain, off-road, and escape situations, the high-torque power requirements of users cannot be met.

[0070] Based on this, embodiments of the present disclosure provide a technical solution. On the basis of increasing the gears of the rear drive of a four-wheel drive vehicle, the shift control of the four-wheel drive vehicle is correspondingly increased. According to the road on which the vehicle is traveling and / or the driving mode, the gears of the rear axle motor are automatically controlled, so that at different gears, the rear axle motor can output different torques. Thus, on the basis of the controllable torque of the rear axle motor, the overall vehicle economy, handling stability and cruising range can be improved, and the driver can be prevented from being distracted during driving and getting into dangerous situations. At the same time, it can be used to meet the power requirements of special terrain modes, providing users with a good driving experience.

[0071] The technical solution provided by the embodiments of the present disclosure can be applied to a four-wheel drive vehicle, and the four-wheel drive vehicle can be a hybrid vehicle. By way of example, the technical solution provided by the embodiments of the present disclosure can be used for gear control of a hybrid electric four-wheel drive vehicle. Among them, the hybrid electric four-wheel drive vehicle can be a hybrid four-wheel drive vehicle, an extended-range hybrid four-wheel drive vehicle or a pure electric four-wheel drive vehicle, and the embodiments of the present disclosure do not make any limitation thereto. Additionally, it should be understood that the hybrid electric four-wheel drive vehicle can include a front axle drive assembly and a rear axle drive assembly. The front axle drive assembly can include an engine, a generator, a front drive motor and a transmission. The front drive motor can be a single-gear drive motor, and the rear axle drive assembly can include a rear drive motor and a two-gear transmission, and the rear drive motor can be a P4 drive motor.

[0072] Figure 1 is a flowchart of a control method for a four-wheel drive vehicle shown according to an exemplary embodiment. The control method includes:

[0073] Step S11, obtaining the road information on which the four-wheel drive vehicle is traveling and / or the driving mode.

[0074] Step S12, controlling the gears of the rear drive of the four-wheel drive vehicle according to the road information on which the vehicle is traveling and / or the driving mode.

[0075] In step S12, at different gears, the rear axle drive motor of the four-wheel drive vehicle outputs different torques.

[0076] The road information on which the vehicle is traveling can be the information of the road on which the four-wheel drive vehicle is currently traveling; or, it can also be the information of the road on which the four-wheel drive vehicle is about to travel.

[0077] In the embodiments of the present disclosure, the road information on which the vehicle is traveling can include (or characterize) the type of the road on which the four-wheel drive vehicle is traveling, that is, the type of the road on which the four-wheel drive vehicle is traveling.

[0078] By way of example, the type of the road on which the vehicle is traveling can be: urban road, snow, sand, mountain, mud, wading, rock, etc. Among them, the urban road can be understood as a non-special road type; snow, sand, mountain, mud, wading and rock can be understood as special road types.

[0079] The driving mode can be the driving mode currently adopted by the four-wheel drive vehicle; or, it can also be the driving mode required by the user.

[0080] In the embodiments of the present disclosure, the driving modes of the four-wheel drive vehicle may include: an energy-saving mode, a standard driving mode, and a sport mode.

[0081] The energy-saving mode can be referred to as the ECO (Ecology Conservation Optimization) mode. In this mode, by means of moderate throttle characteristics and controlling the operation of the air-conditioning system (only when heating or cooling), the fuel economy is improved. When the air conditioner needs to be used, the vehicle system usually automatically switches back to the ECO mode to continue improving the fuel efficiency.

[0082] The standard driving mode can be referred to as the Normal mode. In this mode, the handling feeling of the four-wheel drive vehicle is comfortable and simple. Its design purpose is to achieve the best balance between fuel economy and power performance without sacrificing the vehicle's power performance. The Normal mode is suitable for daily driving on urban roads because it provides balanced performance, neither being biased towards aggressive acceleration nor excessive comfort.

[0083] The sport mode can be referred to as the Sport mode. In this mode, the shift timing of the transmission and the engine speed are optimized to achieve fast and powerful acceleration. The Sport mode may also change the steering feel to make it more suitable for driving situations that require agile response, such as on winding mountain roads.

[0084] In the related art, in different driving modes, the working state of the rear axle drive motor of the four-wheel drive vehicle usually does not change, which easily leads to situations such as low working efficiency of the rear axle drive motor, drag torque (the torque generated due to the rear wheels driving the motor to rotate), and electrical losses. In the embodiments of the present disclosure, corresponding gear control can be achieved in combination with different driving modes to reduce the motor drag torque and electrical losses in the related art.

[0085] In the embodiments of the present disclosure, the driving road information and / or the driving mode can be obtained in a variety of implementation manners.

[0086] As an alternative implementation manner, step S11 includes: obtaining the vehicle state information of the four-wheel drive vehicle; obtaining the first information input by the user, where the first information includes at least one of the required driving mode information, the required driving road information, and the required torque information; obtaining the second information collected by the information collection device, where the second information includes the driving road image and / or the driving road type; determining the driving road information and / or the driving mode according to at least one of the vehicle state information, the first information, and the second information.

[0087] In this embodiment, the driving road information and / or the driving mode can be determined based on at least one piece of information among the vehicle state information, the first information, and the second information.

[0088] In some embodiments, if only one piece of information is required, only that one piece of information can be obtained; if two pieces of information are required, only these two pieces of information can be obtained. That is, it is not necessary to obtain all three pieces of information.

[0089] The vehicle state information can include information such as vehicle speed and throttle state. If the driving road information and / or the driving mode are determined only using the vehicle state information, it can be regarded as a fuzzy judgment. For example, if the vehicle speed is relatively fast (or the throttle force is relatively large), it can be determined that the road type traveled by the four-wheel drive vehicle is a non-special road type. If the vehicle speed is relatively slow (or the throttle force is relatively small), it can be determined that the road type traveled by the four-wheel drive vehicle is a special road type.

[0090] The first information can include the required driving mode information, the required driving road information, and the required torque information; this first information can be understood as the required information input by the user. For example, the user can input the first information through the in-vehicle computer.

[0091] If the driving road information and / or the driving mode are determined only using the first information, for example, the required driving mode can be determined as the driving mode; the required driving road information can be determined as the driving road information; the driving mode and / or the driving road information can be determined according to the required torque.

[0092] In some embodiments, if the required torque is medium, the driving mode can be the sport mode and the driving road information can be the special road type; if the required torque is small, the driving mode can be the energy-saving mode and the driving road information can be the non-special road type; if the required torque is large, the driving mode can be the standard driving mode and the driving road information can be the non-special road type.

[0093] The second information can be understood as the information collected by the corresponding information collection device. For example, the driving road image can be collected by a camera. It can be understood that by performing image processing on the driving road image, extracting the image features therein, and then identifying the image features, the corresponding driving road type can be determined. The driving road type can be collected by some positioning devices, and the collection method is, for example: longitude and latitude positioning. Through longitude and latitude positioning, the driving road type can be directly determined. Therefore, in the embodiments of the present disclosure, the driving road information can directly include the information item of the driving road type, or can include the information that can be used to determine the driving road type.

[0094] If the driving road information and / or driving mode are determined only based on the second information, since both the driving road image and the driving road type belong to the driving road information, the driving road information can be determined based on the second information.

[0095] Exemplarily, driving road features are extracted from the driving road image, and the driving road information is determined based on the driving road features; or, the directly obtained driving road information is determined as the final driving road information; or, the driving road information determined based on the driving road features and the directly obtained driving road information are integrated to determine the final driving road information.

[0096] In some embodiments, if two or more types of information are used to determine the driving road information and / or driving mode, then the corresponding driving road information and / or driving mode can be determined respectively based on one piece of information first; then, the driving road information and / or driving mode determined respectively based on multiple pieces of information are integrated to determine the final driving road information and / or driving mode.

[0097] As an alternative implementation manner, determining the driving road information and / or driving mode based on at least one piece of information among the vehicle state information, the first information, and the second information includes: determining the driving road information based on the driving road image, the driving road type, the required driving road information, and the required torque; determining the driving mode based on the required driving mode and the required torque.

[0098] In this implementation manner, the driving road information can be determined by combining the driving road image, the driving road type, the required driving road information, and the required torque; and the driving mode can be determined based on the required driving mode and the required torque.

[0099] Exemplarily, based on the driving road image, one type of driving road information can be determined; and the driving road type is determined as one type of driving road information; and the required driving road information is used as one type of driving road information; and one type of driving road information can also be determined based on the required torque. Then, it is judged whether there are at least two consistent pieces of driving road information among these four pieces of driving road information. If so, the at least two consistent pieces of driving road information are determined as the final driving road information; if not, the required driving road information can be used as the final driving road information.

[0100] Exemplarily, the required driving mode can be used as one type of driving mode; and one type of driving mode can be determined based on the required torque. Then, it is judged whether these two driving modes are consistent. If so, either one of the driving modes is determined as the final driving mode; if not, the driving mode determined based on the required torque can be determined as the final driving mode.

[0101] In the embodiments of the present disclosure, the information of at least one dimension can be used to determine the driving road information and / or the driving mode; moreover, the information of at least one dimension is relatively easy to obtain, so that the driving road information and / or the driving mode can be determined quickly and accurately.

[0102] In step S12, the gear of the rear drive of the four-wheel drive vehicle is controlled according to the driving road information and / or the driving mode.

[0103] In some embodiments, the target gear can be determined from multiple gears of the four-wheel drive vehicle according to the driving road information and / or the driving mode first, and then the gear of the rear drive of the four-wheel drive vehicle is controlled to be the target gear.

[0104] Figure 2 is a schematic diagram of a hybrid system architecture shown according to an exemplary embodiment, as Figure 2 shown, the four-wheel drive vehicle includes a front axle and a rear axle. The front axle is connected to two front wheels, namely the left front wheel and the right front wheel, through a differential; the rear axle is connected to two rear wheels, namely the left rear wheel and the right rear wheel, through a differential.

[0105] The front axle drive part may include: an engine, a generator, a front axle drive motor, and a hybrid system transmission. The front axle drive motor may be a single-gear drive motor. The rear axle drive part may include: a rear axle drive motor and a two-gear transmission. The rear axle drive motor may be a multi-gear (P4) drive motor.

[0106] In the related art, for the rear axle drive part, the two-gear transmission adopts a fixed transmission ratio to control the rear axle drive motor. Therefore, the rear axle drive motor is equivalent to a single-gear drive motor; while in the embodiments of the present disclosure, the gear control of the rear axle drive motor is increased.

[0107] Furthermore, in the embodiments of the present disclosure, the gears of the rear drive of the four-wheel drive vehicle may include: a first gear, a second gear, and a third gear; the gears of the rear drive of the four-wheel drive vehicle can be understood as the gears of the rear axle drive motor.

[0108] The first gear may be the N gear; when the rear drive of the four-wheel drive vehicle is in the N gear, it means that the torque demand is low. At this time, the front axle drive motor outputs torque, and the rear axle drive motor does not output torque; the driving demand of the whole vehicle is met by the front axle drive motor, so that the drag torque and electrical loss of the rear axle reducer and the rear axle drive motor can be reduced, and the economy and cruising range of the whole vehicle can be improved.

[0109] The second gear may be a high-speed gear; when the rear drive of the four-wheel drive vehicle is in the high-speed gear, both the front axle drive motor and the rear axle drive motor continuously output torque, so that the power performance and handling stability of the whole vehicle can be improved.

[0110] The third gear can be a low-speed gear; when the rear drive of the four-wheel drive vehicle is in the low-speed gear, both the front axle drive motor and the rear axle drive motor output torque, and the torque output by the rear axle drive motor is high torque (higher than the torque output in the high-speed gear and can meet the torque requirements of special driving roads), thereby improving the power performance and passability of the whole vehicle.

[0111] Furthermore, the rear axle drive motor does not output torque in the first gear, and the torque output by the rear axle drive motor in the second gear is less than the torque output by the rear axle drive motor in the third gear.

[0112] In addition, the torque output by the rear axle drive motor in the second gear can also be understood as less than a preset torque. Also, the torque output by the rear axle drive motor in the third gear can be understood as greater than the preset torque. The preset torque can be greater than 0, and this preset torque can be used as the gear dividing line between the second gear and the third gear. If the torque output by the rear axle drive motor is greater than the preset torque, it is the third gear; if the torque output by the rear axle drive motor is less than the preset torque, it is the second gear.

[0113] Therefore, as an alternative implementation, controlling the gear of the rear drive of the four-wheel drive vehicle according to the driving road information and / or driving mode can include: determining a target gear from the first gear, the second gear, and the third gear according to the driving road information and / or driving mode, and controlling the gear of the rear drive of the four-wheel drive vehicle to be the target gear.

[0114] In the embodiments of the present disclosure, the driving road information can represent the driving road type of the four-wheel drive vehicle. Therefore, next, the implementation of step S12 will be introduced based on the driving road type and / or driving mode represented by the driving road information.

[0115] As a first alternative implementation, the gear of the rear drive of the four-wheel drive vehicle can be controlled according to the driving road type. Correspondingly, step S12 can include: if the driving road type belongs to the target driving road type, determining a target gear from the second gear and the third gear, and controlling the gear of the rear drive of the four-wheel drive vehicle to be the target gear.

[0116] In some embodiments, the target driving road type can be the special road type in the foregoing embodiments, that is, any one of the road types of snow, sand, mountain, mud, wading, and rock.

[0117] It can be understood that if the four-wheel drive vehicle is driving on these special roads, the four-wheel drive vehicle requires a large motor output torque. If only the front axle drive motor outputs torque, the requirements cannot be met, and various problems may even easily occur. Therefore, in this case, it is necessary to ensure that the rear axle drive motor outputs torque, and then determine the target gear from the second gear and the third gear.

[0118] As an alternative implementation, determining the target gear from the second gear and the third gear includes: if the target driving road type is snow or mud, determining the second gear as the target gear; if the target driving road type is any one of sand, mountain and rock, determining the third gear as the target gear.

[0119] It can be understood that if the driving road type is snow or mud and the vehicle needs to get out of trouble, it does not require a particularly large torque. Therefore, the rear axle drive motor can operate in a high gear, thereby improving the power performance and handling stability of the whole vehicle.

[0120] However, if the driving road type is any one of sand, mountain and rock and the vehicle needs to get out of trouble, it requires a particularly large torque. Therefore, the rear axle drive motor can operate in a low gear, thereby improving the off-road performance and the ability to get out of trouble of the whole vehicle.

[0121] By judging the output torque requirement of the rear axle drive motor according to the driving road type, an effective and accurate determination of the gear that meets the output torque requirement can be achieved, thereby improving the power performance and handling stability of the whole vehicle on the basis of ensuring the trouble-getting-out requirement, reducing the drag loss and improving the off-road performance.

[0122] As the second alternative implementation, the gear of the rear drive of the four-wheel drive vehicle can be controlled according to the driving mode. Correspondingly, step S12 may include: if the driving mode is the sport mode, determining the second gear as the target gear, and the torque output by the rear axle drive motor in the second gear is less than the preset torque.

[0123] In this implementation, if the driving mode is the sport mode, it means that the demand for power is high and continuous torque output is required. At this time, the rear axle drive motor can continuously output power torque to meet the high-power driving demand, so that the four-wheel drive vehicle can travel at a high speed, improving the power performance and handling stability of the whole vehicle.

[0124] By judging the output torque requirement of the rear axle drive motor according to the driving mode, an effective and accurate determination of the gear that meets the output torque requirement can be achieved, thereby improving the power performance and handling stability of the whole vehicle on the basis of ensuring the trouble-getting-out requirement, reducing the drag loss and improving the off-road performance.

[0125] As the third alternative implementation, the gear of the rear drive of the four-wheel drive vehicle can be controlled according to the driving road information and the driving model. Correspondingly, step S12 may include: if the driving road type does not belong to the target driving road type and the driving mode is the energy-saving mode or the standard driving mode, determining the target gear from the first gear and the second gear, and controlling the gear of the rear drive of the four-wheel drive vehicle to be the target gear.

[0126] In this embodiment, since the type of the driving road does not belong to the target driving road type and the driving mode is the energy-saving mode or the standard driving mode, it indicates that the torque required from the rear-axle motor is not particularly large. Therefore, a more economical gear can be selected from the first gear and the second gear as the target gear to improve the power performance and handling stability of the whole vehicle while reducing power loss.

[0127] In the embodiments of the present disclosure, the principle for determining the target gear can be the economy principle. The economy of the gear can be evaluated by the power loss of the whole vehicle's electric drive. The power loss of the whole vehicle's electric drive can be understood as the power loss of the whole vehicle's motor drive system.

[0128] Therefore, as an alternative embodiment, determine the first power loss of the whole vehicle's electric drive of the four-wheel drive vehicle in the first gear; determine the second power loss of the whole vehicle's electric drive of the four-wheel drive vehicle in the second gear. Correspondingly, determining the target gear from the first gear and the second gear includes: determining the target gear from the first gear and the second gear according to the first power loss of the whole vehicle's electric drive and the second power loss of the whole vehicle's electric drive.

[0129] In some embodiments, the first power loss of the whole vehicle's electric drive and the second power loss of the whole vehicle's electric drive can be the power losses at the corresponding vehicle speeds.

[0130] As an alternative embodiment, determine the first power loss of the whole vehicle's electric drive according to the front-axle information and the torque required for the whole vehicle's motor drive. The front-axle information includes: the rotational speed of the front-axle drive motor, the efficiency of the front-axle drive motor, and the front-axle reduction ratio.

[0131] It can be understood that in the first gear, since the rear-axle drive motor does not output torque and the rear-axle motor remains stationary without drag and other losses during vehicle driving, the total torque required for the whole vehicle's motor drive is output by the front-axle drive motor.

[0132] Exemplarily, the first power loss of the whole vehicle's electric drive can be expressed as:

[0133]

[0134] where P lossN represents the power loss in the Nth gear (i.e., the first gear), P lossF represents the power loss of the front-axle drive motor, T Req represents the torque required for the whole vehicle's motor drive, n F represents the rotational speed of the front-axle drive motor, η F represents the efficiency of the front-axle drive motor, i F represents the front-axle reduction ratio.

[0135] In this embodiment, the effective and accurate determination of the first vehicle electric drive loss power can be achieved through the front axle information and the vehicle motor drive demand torque.

[0136] As an alternative embodiment, determining the second vehicle electric drive loss power of a four-wheel drive vehicle in the second gear includes: determining the second vehicle electric drive loss power according to the front axle information, the rear axle information, the torque demand ratio, and the vehicle motor drive demand torque. The front axle information includes: the front axle drive motor speed, the efficiency of the front axle drive motor, and the front axle reduction ratio. The rear axle information includes: the rear axle drive motor speed, the efficiency of the rear axle drive motor, and the rear axle reduction ratio. The torque demand ratio is the ratio of the torque allocated to the front axle drive motor to the vehicle motor drive demand torque.

[0137] It can be understood that in the second gear, at this time, the rear motor speed runs synchronously with the vehicle speed during vehicle driving, and torque is output according to the torque distribution requirements of the front and rear axle motors. The total vehicle motor drive demand torque is jointly output by the front axle drive motor and the rear axle drive motor.

[0138] Exemplarily, the second vehicle electric drive loss power can be expressed as:

[0139]

[0140] where P lossH represents the loss power in the high gear (i.e., the second gear), P lossF represents the loss power of the front axle drive motor, n F represents the front axle drive motor speed, n F represents the efficiency of the front axle drive motor, i F represents the front axle reduction ratio, P lossR represents the loss power of the rear axle drive motor, n R represents the rear axle drive motor speed, η R represents the efficiency of the rear axle drive motor, i R represents the rear axle reduction ratio, factor represents the torque demand ratio, and T Req represents the vehicle motor drive demand torque.

[0141] In the above embodiment, for the front axle drive motor speed and the rear axle drive motor speed, they can be determined through the vehicle speed. Generally speaking, there is a corresponding relationship between the vehicle speed and the motor speed. Based on this corresponding relationship, when the vehicle speed is known, the corresponding speed can be determined.

[0142] Moreover, for some other information, such as: efficiency, reduction ratio, etc., it can be understood as known parameters and can be directly obtained.

[0143] Through the above implementation manners, it is possible to effectively and accurately determine the first vehicle electric drive loss power and the second vehicle electric drive loss power, and then, based on the two powers, determine a more economical gear from the first gear and the second gear as the target gear.

[0144] Further, determining the target gear from the first gear and the second gear according to the first vehicle electric drive loss power and the second vehicle electric drive loss power may include: if the first vehicle electric drive loss power is greater than the second vehicle electric drive loss power, determining the second gear as the target gear; if the first vehicle electric drive loss power is less than or equal to the second vehicle electric drive loss power, determining the first gear as the target gear.

[0145] In this implementation manner, the gear with a smaller vehicle electric drive loss power is determined as the target gear, so that the economy of the target gear is higher.

[0146] In some embodiments, in addition to considering the vehicle electric drive loss power, it is also possible to consider whether the output torque of the front axle drive motor meets the vehicle motor drive demand torque, and determine the target gear by combining the two aspects.

[0147] Therefore, as an alternative implementation manner, determining the target gear from the first gear and the second gear according to the first vehicle electric drive loss power and the second vehicle electric drive loss power includes: determining the target gear from the first gear and the second gear according to the first vehicle electric drive loss power, the second vehicle electric drive loss power, the maximum output torque of the front axle drive motor, and the vehicle motor drive demand torque.

[0148] Wherein, the maximum output torque of the front axle drive motor is a known parameter of the front axle drive motor and can be directly obtained.

[0149] As an alternative implementation manner, if the first vehicle electric drive loss power is less than or equal to the second vehicle electric drive loss power, and the vehicle motor drive demand torque and the maximum output torque of the front axle drive motor meet a preset relationship, determining the first gear as the target gear; if the first vehicle electric drive loss power is greater than the second vehicle electric drive loss power, and the vehicle motor drive demand torque and the maximum output torque of the front axle drive motor do not meet the preset relationship, determining the second gear as the target gear.

[0150] In some embodiments, the preset relationship is any one of the following: the vehicle motor drive demand torque is less than or equal to the maximum output torque of the front axle drive motor; the vehicle motor drive demand torque is less than or equal to the difference between the maximum output torque of the front axle drive motor and a preset torque, and the preset torque is the torque required for the drive motor to switch.

[0151] In some embodiments, a preset torque is used to characterize the torque required for the switching of the drive motor. By considering this torque, it is possible to avoid the situation of untimely response during the gear shifting process of the rear axle drive motor.

[0152] Therefore, the above gear determination process can be expressed as: when P lossN ≤P lossH and T Req ≤(T Fwhole -Δt), the target gear is gear N; when P lossN >P lossH or T Req >(T Fwhole -Δt), the target gear is the high-speed gear. Wherein, T Fwhole represents the maximum output torque of the front axle drive motor, represents the preset torque, Δt can also be called the reserved response torque, and the meanings of the representations of other parameters can refer to the foregoing embodiments.

[0153] Through this implementation manner, it is possible to combine the relationship between the torque required for the vehicle's motor drive and the maximum output torque of the front axle drive motor to achieve a more reasonable determination of the target gear, so that the target gear can not only meet the economic requirements but also meet the torque requirements.

[0154] As another alternative implementation manner, according to the driving road information and the driving mode, control the gear of the rear drive of the four-wheel drive vehicle, including: if the driving road type does not belong to the target driving road type and the driving mode is the sport mode, determine the second gear as the target gear and control the gear of the rear drive of the four-wheel drive vehicle to be the target gear.

[0155] In this implementation manner, if the driving road type does not belong to the target driving road type and the driving mode is the sport mode, it means that the demand for power is high and there is no need to get out of trouble, and continuous torque output is required. At this time, the second gear can be determined as the target gear. Thus, the rear axle drive motor can continuously output power torque to meet the high-power driving requirements, enabling the four-wheel drive vehicle to travel at high speed and improving the vehicle's power performance and handling stability.

[0156] In step S12, after determining the target gear, gear shifting control can be performed according to the vehicle state to achieve more stable gear shifting control. For example, if the vehicle speed is relatively high, the vehicle speed can be reduced first and then the gear is shifted to reduce the risk.

[0157] Figure 3 is a control flow chart of a four-wheel drive vehicle shown according to an exemplary embodiment. As Figure 3 shown, first obtain the vehicle driving road information, then obtain the user requirements and the vehicle state; then, based on the road information and the user requirements, determine the target switching gear; finally, perform gear shifting according to the vehicle state.

[0158] Figure 4 is a schematic diagram showing the relationship between vehicle speed and torque according to an exemplary embodiment. Figure 4 As shown, there are three types of torque involved: 2H limit torque, 4H limit torque, and 4L limit torque. 2H limit torque is the limit torque for N gear, 4H limit torque is the limit torque for high gear, and 4L is the limit torque for low gear. It can be seen that low gear has the highest limit torque. Furthermore, N gear has a high-efficiency range within which power loss is minimal and efficiency is high.

[0159] Therefore, in one application scenario, the rear axle drive motor gear is adjusted according to the type of road and driver demand. When the power demand on ordinary urban roads is low, the rear axle drive motor is controlled to enter N gear, that is, 2H drive mode. At this time, the front axle drive motor meets the vehicle's drive demand, reducing the drag torque and power loss of the rear axle reducer and rear drive motor, and improving the vehicle's economy and range. When the power demand on urban roads is high or in special terrain such as snow, the rear axle drive motor is controlled to enter high gear, that is, 4H drive mode. At this time, the front and rear axle drive motors output simultaneously to meet the vehicle's drive demand, improving the vehicle's power and handling stability. In some special terrain conditions (such as mountains, rocks, sand, etc.), the rear axle drive motor is controlled to enter low gear, that is, 4L drive mode. At this time, the front and rear axle drive motors output simultaneously to meet the vehicle's drive demand, and the rear axle can provide high torque output, improving the vehicle's power and passability.

[0160] Through the introduction of the embodiments of the present disclosure, it can be seen that, on the one hand, the technical solution of the embodiments of the present disclosure can achieve optimal gear control of the rear axle drive motor of a four-wheel drive vehicle; based on the fact that the rear axle drive motor maintains a complete mechanical connection with the wheels, and there are technical problems such as drag loss and poor economy, by calculating the power loss of different target gears, the lowest loss is selected as the target gear control by comparison; by automatically adjusting the rear axle drive motor's engagement and disengagement gear (i.e., low gear) control, system losses are reduced, and economy and cruising range are improved.

[0161] On the other hand, the gear position is automatically adjusted according to the type of road being driven to improve power output. When the vehicle enters a special type of road, the traditional driving mode is mainly switched manually by the driver. At this time, the road conditions are complicated, and the driver responds slowly by observing and manually switching, and is easily distracted and may cause danger and other technical problems. By automatically identifying the type of road being driven and adaptively adjusting the driving mode, the vehicle's power economy, handling stability and escape ability are improved.

[0162] Based on the same concept, the present disclosure also provides a control device for a four-wheel drive vehicle. Figure 5It is a block diagram of a control device for a four-wheel drive vehicle shown according to an exemplary embodiment. As Figure 5 shown, the control device 500 of the four-wheel drive vehicle may include:

[0163] An acquisition module 501, configured to: acquire the driving road information and / or driving mode of the four-wheel drive vehicle;

[0164] A control module 502, configured to: control the gear of the rear-wheel drive of the four-wheel drive vehicle according to the driving road information and / or the driving mode, wherein, at different gears, the rear axle drive motor of the four-wheel drive vehicle outputs different torques.

[0165] Optionally, the gears of the rear-wheel drive of the four-wheel drive vehicle include: a first gear, a second gear, and a third gear;

[0166] The rear axle drive motor does not output torque in the first gear, and the torque output by the rear axle drive motor in the second gear is less than the torque output by the rear axle drive motor in the third gear.

[0167] Optionally, the driving road information is used to characterize the driving road type of the four-wheel drive vehicle, and the control module 502 is further configured to:

[0168] If the driving road type belongs to the target driving road type, determine the target gear from the second gear and the third gear, and control the gear of the rear-wheel drive of the four-wheel drive vehicle to be the target gear;

[0169] wherein, the torque output by the rear axle drive motor in the second gear is less than the torque output by the rear axle drive motor in the third gear.

[0170] Optionally, the control module 502 is further configured to: if the target driving road type is snow or mud, determine the second gear as the target gear;

[0171] If the target driving road type is any one of sand, mountain, and rock, determine the third gear as the target gear.

[0172] Optionally, the control module 502 is further configured to: if the driving mode is a sport mode, determine the second gear as the target gear, and the torque output by the rear axle drive motor in the second gear is less than a preset torque.

[0173] Optionally, the control module 502 is further configured to: if the driving road type does not belong to the target driving road type, and the driving mode is an energy-saving mode or a standard driving mode, determine the target gear from the first gear and the second gear, and control the gear of the rear-wheel drive of the four-wheel drive vehicle to be the target gear;

[0174] The rear axle drive motor does not output torque in the first gear, and the torque output by the rear axle drive motor in the second gear is less than a preset torque.

[0175] Optionally, the control module 502 is further configured to: determine a first overall vehicle electric drive loss power of the four-wheel drive vehicle in the first gear; determine a second overall vehicle electric drive loss power of the four-wheel drive vehicle in the second gear; and is further configured to: determine the target gear from the first gear and the second gear according to the first overall vehicle electric drive loss power and the second overall vehicle electric drive loss power.

[0176] Optionally, the control module 502 is further configured to: determine the first overall vehicle electric drive loss power according to the front axle information and the overall vehicle motor drive demand torque, where the front axle information includes: front axle drive motor speed, efficiency of the front axle drive motor, and front axle reduction ratio.

[0177] Optionally, the control module 502 is further configured to: determine the second overall vehicle electric drive loss power according to the front axle information, rear axle information, torque demand ratio, and overall vehicle motor drive demand torque, where the front axle information includes: front axle drive motor speed, efficiency of the front axle drive motor, and front axle reduction ratio, the rear axle information includes: rear axle drive motor speed, efficiency of the rear axle drive motor, and rear axle reduction ratio, and the torque demand ratio is the ratio of the torque allocated to the front axle drive motor to the overall vehicle motor drive demand torque.

[0178] Optionally, the control module 502 is further configured to: if the first overall vehicle electric drive loss power is greater than the second overall vehicle electric drive loss power, determine the second gear as the target gear;

[0179] If the first overall vehicle electric drive loss power is less than or equal to the second overall vehicle electric drive loss power, determine the first gear as the target gear.

[0180] Optionally, the control module 502 is further configured to: determine the target gear from the first gear and the second gear according to the first overall vehicle electric drive loss power, the second overall vehicle electric drive loss power, the maximum output torque of the front axle drive motor, and the overall vehicle motor drive demand torque.

[0181] Optionally, the control module 502 is further configured to: if the first overall vehicle electric drive loss power is less than or equal to the second overall vehicle electric drive loss power, and the overall vehicle motor drive demand torque and the maximum output torque of the front axle drive motor satisfy a preset relationship, determine the first gear as the target gear;

[0182] If the first vehicle electric drive loss power is greater than the second vehicle electric drive loss power, and the vehicle motor drive demand torque and the maximum output torque of the front axle drive motor do not satisfy the preset relationship, determine the second gear as the target gear.

[0183] Optionally, the preset relationship is any one of the following:

[0184] The vehicle motor drive demand torque is less than or equal to the maximum output torque of the front axle drive motor;

[0185] The vehicle motor drive demand torque is less than or equal to the difference between the maximum output torque of the front axle drive motor and the preset torque, and the preset torque is the torque required for the drive motor to switch.

[0186] Optionally, the control module 502 is further configured to: if the type of the driving road does not belong to the target driving road type, and the driving mode is the sport mode, determine the second gear as the target gear, and control the gear of the rear drive of the four-wheel drive vehicle to be the target gear, and the torque output by the rear axle drive motor in the second gear is less than the preset torque.

[0187] Optionally, the acquisition module 501 is further configured to: acquire the vehicle state information of the four-wheel drive vehicle;

[0188] Acquire the first information input by the user, where the first information includes at least one of the required driving mode information, the required driving road information, and the required torque information;

[0189] Acquire the second information collected by the information acquisition device, where the second information includes: the driving road image and / or the driving road type;

[0190] Determine the driving road information and / or the driving mode according to at least one of the vehicle state information, the first information, and the second information.

[0191] Optionally, the acquisition module 501 is further configured to: determine the driving road information according to the driving road image, the driving road type, the required driving road information, and the required torque;

[0192] Determine the driving mode according to the required driving mode and the required torque.

[0193] Please refer to Figure 6 , Figure 6It is a schematic functional block diagram of a vehicle shown according to an exemplary embodiment. Vehicle 600 may include various subsystems. For example, an infotainment system 610, a perception system 620, a decision control system 630, a drive system 640, and a computing platform 650. Among them, vehicle 600 may also include more or fewer subsystems, and each subsystem may include multiple components. In addition, each subsystem and each component of vehicle 600 may be interconnected by wired or wireless means.

[0194] In some embodiments, the infotainment system 610 may include a communication system, an entertainment system, a navigation system, and the like.

[0195] The perception system 620 may include several sensors for sensing information about the environment around vehicle 600. For example, the perception system 620 may include a global positioning system (the global positioning system may be a GPS system, a Beidou system, or other positioning systems), an inertial measurement unit (IMU), lidar, millimeter-wave radar, ultrasonic radar, and a camera device.

[0196] The decision control system 630 may include a computing system, a vehicle controller, a steering system, an accelerator, and a braking system.

[0197] The drive system 640 may include components that provide powered movement for vehicle 600. In one embodiment, the drive system 640 may include an engine, an energy source, a powertrain, and wheels. The engine may be one or a combination of an internal combustion engine, an electric motor, and an air compression engine. The engine can convert the energy provided by the energy source into mechanical energy.

[0198] Some or all functions of vehicle 600 are controlled by the computing platform 650. The computing platform 650 may include at least one processor 651 and a memory 652. The processor 651 may execute instructions 653 stored in the memory 652.

[0199] The processor 651 may be any conventional processor, such as a commercially available CPU. The processor may also include, for example, a Graphic Process Unit (GPU), a Field Programmable Gate Array (FPGA), a System on Chip (SOC), an Application Specific Integrated Circuit (ASIC), or a combination thereof.

[0200] The memory 652 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disc.

[0201] In addition to the instructions 653, the memory 652 can also store data, such as road maps, route information, data on the position, direction, speed, etc. of the vehicle. The data stored in the memory 652 can be used by the computing platform 650.

[0202] In an embodiment of the present disclosure, the processor 651 can execute the instructions 653 to complete all or part of the steps of the above-mentioned four-wheel drive vehicle control method.

[0203] In another exemplary embodiment, a controller is further provided. The controller can be part of the aforementioned vehicle. The controller can be an integrated circuit (IC) or a chip. The integrated circuit can be a single IC or a collection of multiple ICs; the chip can include, but is not limited to, the following types: GPU (Graphics Processing Unit), CPU (Central Processing Unit), FPGA (Field Programmable Gate Array), DSP (Digital Signal Processor), ASIC (Application Specific Integrated Circuit), SOC (System on Chip), etc. The above-mentioned integrated circuit or chip can be used to execute executable instructions (or code) to implement the above-mentioned four-wheel drive vehicle control method. The executable instructions can be stored in the integrated circuit or chip, or can be obtained from other devices or equipment. For example, the integrated circuit or chip includes a processor, a memory, and an interface for communicating with other devices. The executable instructions can be stored in the memory, and when the executable instructions are executed by the processor, the above-mentioned four-wheel drive vehicle control method is implemented; or, the integrated circuit or chip can receive the executable instructions through the interface and transmit them to the processor for execution to implement the above-mentioned four-wheel drive vehicle control method.

[0204] The present disclosure also provides a computer-readable storage medium, on which computer program instructions are stored. When the program instructions are executed by a processor, the steps of the control method of the four-wheel drive vehicle provided by the present disclosure are implemented.

[0205] In another exemplary embodiment, a computer program product is also provided. The computer program product includes a computer program that can be executed by a programmable device. The computer program has a code portion for executing the above-mentioned control method of the four-wheel drive vehicle when executed by the programmable device.

[0206] The preferred embodiments of the present disclosure have been described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0207] In addition, it should be noted that, among the various specific technical features described in the above specific embodiments, they can be combined in any suitable manner without conflict. To avoid unnecessary repetition, the present disclosure will not separately describe various possible combination manners.

[0208] Furthermore, any combination can be made between various different embodiments of the present disclosure, as long as it does not violate the idea of the present disclosure, and it should also be regarded as the content disclosed by the present disclosure.

Claims

1. A control method for a four-wheel drive vehicle, characterized in that, The control method includes: Obtaining the driving road information and / or driving mode of the four-wheel drive vehicle; Controlling the gear of the rear drive of the four-wheel drive vehicle according to the driving road information and / or the driving mode, wherein, at different gears, the rear axle drive motor of the four-wheel drive vehicle outputs different torques.

2. The control method according to claim 1, wherein The gears of the rear drive of the four-wheel drive vehicle include: a first gear, a second gear, and a third gear; The rear axle drive motor does not output torque in the first gear, and the torque output by the rear axle drive motor in the second gear is less than the torque output by the rear axle drive motor in the third gear.

3. The control method according to claim 1, characterized in that, The driving road information is used to characterize the type of the driving road of the four-wheel drive vehicle. Controlling the gear of the rear drive of the four-wheel drive vehicle according to the driving road information includes: If the driving road type belongs to the target driving road type, determining the target gear from the second gear and the third gear, and controlling the gear of the rear drive of the four-wheel drive vehicle to be the target gear; Wherein, the torque output by the rear axle drive motor in the second gear is less than the torque output by the rear axle drive motor in the third gear.

4. The control method according to claim 3, wherein The determining the target gear from the second gear and the third gear includes: If the target driving road type is snow or mud, determining the second gear as the target gear; If the target driving road type is any one of sand, mountain, and rock, determining the third gear as the target gear.

5. The control method according to claim 1, wherein Controlling the gear of the rear drive of the four-wheel drive vehicle according to the driving mode includes: If the driving mode is a sport mode, determining the second gear as the target gear, and the torque output by the rear axle drive motor in the second gear is less than a preset torque.

6. The control method according to claim 1, wherein The driving road information is used to characterize the type of the driving road of the four-wheel drive vehicle. Controlling the gear of the rear drive of the four-wheel drive vehicle according to the driving road information and the driving mode includes: If the driving road type does not belong to the target driving road type, and the driving mode is an energy-saving mode or a standard driving mode, determining the target gear from the first gear and the second gear, and controlling the gear of the rear drive of the four-wheel drive vehicle to be the target gear; The rear axle drive motor does not output torque in the first gear, and the torque output by the rear axle drive motor in the second gear is less than the preset torque.

7. The control method according to claim 6, wherein The control method further includes: Determining a first overall vehicle electric drive loss power of the four-wheel drive vehicle in the first gear; Determining a second overall vehicle electric drive loss power of the four-wheel drive vehicle in the second gear; The determining the target gear from the first gear and the second gear includes: Determining the target gear from the first gear and the second gear according to the first overall vehicle electric drive loss power and the second overall vehicle electric drive loss power.

8. The control method according to claim 7, wherein The determining the first overall vehicle electric drive loss power of the four-wheel drive vehicle in the first gear includes: Determining the first overall vehicle electric drive loss power according to the front axle information and the overall vehicle motor drive demand torque, where the front axle information includes: the front axle drive motor speed, the efficiency of the front axle drive motor, and the front axle reduction ratio.

9. The control method according to claim 7, characterized in that, Determining the second overall vehicle electric drive loss power of the four-wheel drive vehicle in the second gear includes: Determining the second overall vehicle electric drive loss power according to the front axle information, rear axle information, torque demand ratio, and overall vehicle motor drive demand torque. The front axle information includes: front axle drive motor speed, efficiency of the front axle drive motor, and front axle reduction ratio. The rear axle information includes: rear axle drive motor speed, efficiency of the rear axle drive motor, and rear axle reduction ratio. The torque demand ratio is the ratio of the torque allocated to the front axle drive motor to the overall vehicle motor drive demand torque.

10. The control method according to claim 7, characterized in that, Determining the target gear from the first gear and the second gear according to the first overall vehicle electric drive loss power and the second overall vehicle electric drive loss power includes: If the first overall vehicle electric drive loss power is greater than the second overall vehicle electric drive loss power, determining the second gear as the target gear; If the first overall vehicle electric drive loss power is less than or equal to the second overall vehicle electric drive loss power, determining the first gear as the target gear.

11. The control method according to claim 7, characterized in that, Determining the target gear from the first gear and the second gear according to the first overall vehicle electric drive loss power and the second overall vehicle electric drive loss power includes: Determining the target gear from the first gear and the second gear according to the first overall vehicle electric drive loss power, the second overall vehicle electric drive loss power, the maximum output torque of the front axle drive motor, and the overall vehicle motor drive demand torque.

12. The control method according to claim 11, wherein Determining the target gear from the first gear and the second gear according to the first overall vehicle electric drive loss power, the second overall vehicle electric drive loss power, the maximum output torque of the front axle drive motor, and the overall vehicle motor drive demand torque includes: If the first overall vehicle electric drive loss power is less than or equal to the second overall vehicle electric drive loss power, and the overall vehicle motor drive demand torque and the maximum output torque of the front axle drive motor satisfy a preset relationship, determining the first gear as the target gear; If the first overall vehicle electric drive loss power is greater than the second overall vehicle electric drive loss power, and the overall vehicle motor drive demand torque and the maximum output torque of the front axle drive motor do not satisfy the preset relationship, determining the second gear as the target gear.

13. The control method according to claim 12, characterized in that, The preset relationship is any one of the following: The overall vehicle motor drive demand torque is less than or equal to the maximum output torque of the front axle drive motor; The overall vehicle motor drive demand torque is less than or equal to the difference between the maximum output torque of the front axle drive motor and a preset torque, where the preset torque is the torque required for drive motor switching.

14. The control method according to claim 1, wherein The driving road information is used to characterize the driving road type of the four-wheel drive vehicle. Controlling the gear of the rear drive of the four-wheel drive vehicle according to the driving road information and the driving mode includes: If the driving road type does not belong to the target driving road type, and the driving mode is the sport mode, determining the second gear as the target gear, and controlling the gear of the rear drive of the four-wheel drive vehicle to be the target gear, where the torque output by the rear axle drive motor in the second gear is less than the preset torque.

15. The control method according to any one of claims 1-14, characterized in that, Obtaining the driving road information and / or driving mode of the four-wheel drive vehicle includes: Obtaining the vehicle status information of the four-wheel drive vehicle; Obtaining the first information input by the user, where the first information includes at least one of the required driving mode information, required driving road information, and required torque information; Obtaining the second information collected by the information collection device, where the second information includes a driving road image and / or driving road type; Determining the driving road information and / or the driving mode based on at least one of the vehicle status information, the first information, and the second information.

16. The control method according to claim 15, wherein The determining the driving road information and / or the driving mode based on at least one of the vehicle status information, the first information, and the second information includes: Determining the driving road information based on the driving road image, the driving road type, the required driving road information, and the required torque; Determining the driving mode based on the required driving mode and the required torque.

17. A controller, characterized in that, Including: A memory having a computer program stored thereon; A processor for executing the computer program in the memory so that the controller executes the control method of the four-wheel drive vehicle according to any one of claims 1-16.

18. A vehicle, characterized in that, Including the controller according to claim 17.

19. A computer-readable storage medium having computer program instructions stored thereon, characterized in that, When the program instructions are executed by the processor, the control method of the four-wheel drive vehicle according to any one of claims 1-16 is implemented.

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