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

Abstract

A control method for a four-wheel drive vehicle, a vehicle (600), a controller, and a storage medium. The control method comprises: acquiring at least one of driving road information or a driving mode of a four-wheel drive vehicle; on the basis of the driving road information and / or the driving mode, controlling the gear of the rear drive of the four-wheel drive vehicle, wherein under different gears, a rear axle drive motor (202) of the four-wheel drive vehicle outputs different torques.

Description

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

[0001] This application claims priority to Chinese patent application No. 202410154414.3, filed on February 1, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to the field of vehicle control technology, and in particular to a control method, a vehicle, a controller, and a storage medium for a four-wheel drive vehicle. Background Art

[0003] With the rapid development of new energy vehicles, hybrid vehicles are also developing. Consumers have higher and higher demands for the power configuration and performance of hybrid vehicles, and four-wheel drive systems are gradually being applied to hybrid vehicles.

[0004] Compared with traditional two-wheel drive vehicles, four-wheel drive vehicles have better power and operational stability and are more suitable for hybrid vehicles.

[0005] Summary of the Invention

[0006] The purpose of the present disclosure is to provide a control method, vehicle, controller and storage medium for a four-wheel drive vehicle, which can control the output torque of the rear axle drive motor through gear switching, thereby improving the power and handling stability of the entire vehicle, enabling the four-wheel drive vehicle to better cope with the driving requirements of special driving roads and enhance the driving experience of the four-wheel drive vehicle.

[0007] In order to achieve the above objectives, in a first aspect, the present disclosure provides a control method for a four-wheel drive vehicle, the control method comprising:

[0008] obtaining at least one of driving road information or driving mode of the four-wheel drive vehicle;

[0009] The rear-wheel drive gear of the four-wheel drive vehicle is controlled according to at least one of the driving road information or the driving mode, wherein the rear-axle drive motor of the four-wheel drive vehicle outputs different torques at different gears.

[0010] In some embodiments, the rear-wheel drive gears of the four-wheel drive vehicle include: a first gear, a second gear, and a third gear;

[0011] 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 smaller than the torque output by the rear axle drive motor in the third gear.

[0012] In some embodiments, the driving road information is used to characterize the driving road type of the four-wheel drive vehicle, and controlling the rear-wheel drive gear of the four-wheel drive vehicle according to the driving road information includes:

[0013] 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 rear-wheel drive gear of the four-wheel drive vehicle to the target gear;

[0014] The torque output by the rear axle drive motor in the second gear is smaller than the torque output by the rear axle drive motor in the third gear.

[0015] In some embodiments, determining the target gear from the second gear and the third gear includes:

[0016] If the target driving road type is snow or mud, determining the second gear as the target gear;

[0017] If the target driving road type is any one of sand, mountain and rock, the third gear is determined as the target gear.

[0018] In some embodiments, controlling the rear-wheel drive gear of the four-wheel drive vehicle according to the driving mode includes:

[0019] 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.

[0020] In some embodiments, the driving road information is used to characterize the driving road type of the four-wheel drive vehicle, and controlling the rear-wheel drive gear of the four-wheel drive vehicle according to the driving road information and the driving mode includes:

[0021] 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 a target gear from the first gear and the second gear, and controlling the rear-wheel drive gear of the four-wheel drive vehicle to the target gear;

[0022] 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.

[0023] In some embodiments, the control method further includes:

[0024] determining a first vehicle electric drive loss power of the four-wheel drive vehicle in the first gear;

[0025] determining a second vehicle electric drive loss power of the four-wheel drive vehicle in the second gear;

[0026] The determining the target gear position from the first gear position and the second gear position includes:

[0027] The target gear is determined 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.

[0028] In some embodiments, determining the first vehicle electric drive power loss of the four-wheel drive vehicle in the first gear includes:

[0029] The first vehicle electric drive loss power is determined based on front axle information and the vehicle motor drive required torque, wherein the front axle information includes: front axle drive motor speed, front axle drive motor efficiency and front axle reduction ratio.

[0030] In some embodiments, determining the second vehicle electric drive loss power of the four-wheel drive vehicle in the second gear includes:

[0031] The second vehicle electric drive loss power is determined based on 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.

[0032] In some embodiments, determining the target gear from the first gear and the second gear according to the first vehicle electric drive power loss and the second vehicle electric drive power loss includes:

[0033] If the first vehicle electric drive power loss is greater than the second vehicle electric drive power loss, determining the second gear as the target gear;

[0034] If the first vehicle electric drive loss power is less than or equal to the second vehicle electric drive loss power, the first gear is determined as the target gear.

[0035] In some embodiments, determining the target gear from the first gear and the second gear according to the first vehicle electric drive power loss and the second vehicle electric drive power loss includes:

[0036] The target gear is determined 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.

[0037] In some embodiments, determining the target gear from the first gear and the second gear according to the first vehicle electric drive power loss, the second vehicle electric drive power loss, the maximum output torque of the front axle drive motor, and the vehicle motor drive required torque includes:

[0038] 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 required torque and the maximum output torque of the front axle drive motor satisfy a preset relationship, the first gear is determined as the target gear;

[0039] If the first vehicle electric drive loss power is greater than the second vehicle electric drive loss power, and the vehicle motor drive required torque and the front axle drive motor maximum output torque do not satisfy the preset relationship, the second gear is determined as the target gear.

[0040] In some embodiments, the preset relationship is any one of the following:

[0041] The vehicle motor drive required torque is less than or equal to the maximum output torque of the front axle drive motor;

[0042] The vehicle motor drive required 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 when the drive motor is switched.

[0043] In some embodiments, the driving road information is used to characterize the driving road type of the four-wheel drive vehicle, and controlling the rear-wheel drive gear of the four-wheel drive vehicle according to the driving road information and the driving mode includes:

[0044] If the driving road type does not belong to the target driving road type and the driving mode is the sports mode, the second gear is determined as the target gear, and the rear-wheel drive gear of the four-wheel drive vehicle is controlled 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.

[0045] In some embodiments, obtaining at least one of the driving road information and the driving mode of the four-wheel drive vehicle includes:

[0046] Obtaining vehicle status information of the four-wheel drive vehicle;

[0047] Acquiring first information input by a user, the first information comprising at least one of required driving mode information, required driving road information, and required torque information;

[0048] Acquiring second information collected by the information collection device, the second information including: at least one of a driving road image and a driving road type;

[0049] At least one of the driving road information and the driving mode is determined based on at least one of the vehicle state information, the first information, and the second information.

[0050] In some embodiments, determining at least one of the driving road information and the driving mode based on at least one of the vehicle state information, the first information, and the second information includes:

[0051] determining the driving road information according to the driving road image, the driving road type, the required driving road information, and the required torque;

[0052] The driving mode is determined according to the required driving mode and the required torque.

[0053] In a second aspect, the present disclosure provides a controller comprising a memory and a processor.

[0054] The memory stores a computer program;

[0055] The processor is used to execute the computer program in the memory so that the controller executes the control method of the four-wheel drive vehicle according to the first aspect.

[0056] In a third aspect, the present disclosure provides a vehicle, comprising: a controller as described in the second aspect.

[0057] In a fourth aspect, the present disclosure provides a computer-readable storage medium having computer program instructions stored thereon, which, when executed by a processor, implement the control method for the four-wheel drive vehicle described in the first aspect.

[0058] The above technical solution not only increases the rear-wheel drive gear ratio of a four-wheel drive vehicle, but also adds corresponding shift control for the four-wheel drive vehicle. The rear axle motor gear ratio is automatically controlled based on at least one of the vehicle's road or driving mode, thereby improving vehicle handling stability and reducing the problem of slow shift response caused by manual driver operation. Furthermore, the rear axle drive motor can output different torques in different gears, thereby improving vehicle dynamics, enabling the four-wheel drive vehicle to better cope with the driving needs of special roads and enhancing the driving experience of the four-wheel drive vehicle.

[0059] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] FIG1 is a flow chart of a method for controlling a four-wheel drive vehicle according to some embodiments;

[0061] FIG2 is a schematic diagram of a hybrid system architecture according to some embodiments;

[0062] FIG3 is another flow chart of a method for controlling a four-wheel drive vehicle according to some embodiments;

[0063] FIG4 is a schematic diagram of the relationship between vehicle speed and torque according to some embodiments;

[0064] FIG5 is a block diagram of a control device for a four-wheel drive vehicle according to some embodiments;

[0065] FIG6 is a block diagram of the functionality of a vehicle according to some embodiments. DETAILED DESCRIPTION

[0066] 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.

[0067] 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.

[0068] Four-wheel drive vehicles have better power and operational stability and are more suitable for hybrid vehicles.

[0069] First, compared to traditional two-wheel drive vehicles, four-wheel drive vehicles offer significant improvements in power and handling stability, but still suffer from a disadvantage in terms of economy. Second, the electric motor is typically connected to the drive wheels via a fixed-ratio reducer. While this can generally meet user needs on ordinary roads without special terrain, it cannot meet the high-torque power and maneuverability requirements for special terrain (such as all-terrain, off-road conditions, and escape requirements). Furthermore, when the vehicle enters special terrain mode, the traditional drive mode is primarily switched manually by the driver. Due to the complex road conditions, the driver's response to manual switching is slow and can easily lead to distraction, which can be dangerous.

[0070] Therefore, the rear axle motor of hybrid four-wheel drive vehicles in the related art is only connected to the drive wheels through a speed reducer with a fixed transmission ratio. That is, the rear axle motor in the related art usually corresponds to only one drive gear, making the output torque of the rear axle motor unadjustable. Moreover, under conditions with low power requirements, such as ordinary urban roads, if the rear axle motor has little or no torque distribution, it will lead to low operating efficiency, drag torque (the torque generated by the rear wheels driving the motor to rotate), and power loss. At the same time, when encountering all-terrain, off-road conditions, and escape needs, the above-mentioned four-wheel drive vehicles cannot meet the user's high torque power requirements.

[0071] Based on this, some embodiments of the present disclosure provide a technical solution that, while increasing the rear-wheel drive gear ratio of a four-wheel drive vehicle, also increases gear shift control for the four-wheel drive vehicle. This solution automatically controls the gear ratio of the rear axle motor based on at least one of the road or driving mode the vehicle is traveling on, allowing the rear axle motor to output different torques in different gear ratios. Thus, based on the controllable torque of the rear axle motor, the vehicle's economy, handling stability, and cruising range can be improved, reducing the risk of driver distraction during driving. Furthermore, this solution can be used to meet the power requirements of special terrain modes, providing users with a superior driving experience.

[0072] The technical solutions provided in some embodiments of the present disclosure can be applied to four-wheel drive vehicles, which can be hybrid vehicles. For example, the technical solutions provided in some embodiments of the present disclosure can be used to control the gear position of a hybrid electric four-wheel drive vehicle. For example, 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, which is not limited in this disclosure.

[0073] It should also be understood that a hybrid electric four-wheel drive vehicle may include a front axle drive assembly and a rear axle drive assembly. The front axle drive assembly may include an engine, a generator, a front-drive motor, and a transmission. For example, the front-drive motor may be a single-speed drive motor. The rear axle drive assembly may include a rear-drive motor and a two-speed transmission. The rear-drive motor may be a P4 drive motor.

[0074] FIG1 is a flow chart of a control method for a four-wheel drive vehicle according to some embodiments. As shown in FIG1 , the control method includes:

[0075] Step S11 , obtaining at least one of the driving road information or the driving mode of the four-wheel drive vehicle.

[0076] Step S12: controlling the rear-wheel drive gear of the four-wheel drive vehicle according to at least one of the driving road information or the driving mode.

[0077] In step S12 , the rear axle drive motor of the four-wheel drive vehicle outputs different torques at different gear positions.

[0078] The driving road information may be information about the road on which the four-wheel drive vehicle is currently driving, or information about the road on which the four-wheel drive vehicle will soon drive.

[0079] In some embodiments of the present disclosure, the driving road information may include (or represent) the driving road type of the four-wheel drive vehicle, that is, the type of the road on which the four-wheel drive vehicle is driving.

[0080] For example, the driving road type can be: city road, snow, sand, mountain, mud, wading, rock, etc. Here, city road can be understood as a non-special road type; snow, sand, mountain, mud, wading and rock can be understood as special road types.

[0081] The driving mode may be the driving mode currently adopted by the four-wheel drive vehicle, or may be the driving mode required by the user.

[0082] In some embodiments of the present disclosure, the driving modes of a four-wheel drive vehicle may include: an energy-saving mode, a standard driving mode, and a sports mode.

[0083] Energy-saving mode, also known as ECO (Ecology Conservation Optimization) mode, improves fuel economy by adjusting the throttle response and controlling the air conditioning system (only when heating or cooling). When the air conditioning is needed, the vehicle system automatically switches back to ECO mode to continue improving fuel efficiency.

[0084] The standard driving mode, often referred to as Normal mode, provides comfortable and easy handling for all-wheel-drive vehicles. It's designed to achieve the optimal balance between fuel economy and performance while maintaining vehicle dynamics. Normal mode is ideal for everyday urban driving, offering balanced performance that favors neither aggressive acceleration nor excessive comfort.

[0085] Sport mode, which could be called Sport mode, optimizes transmission shift timing and engine speed for quick and powerful acceleration. Sport mode may also change the steering feel, making it more suitable for driving situations that require agile responses, such as on winding mountain roads.

[0086] In related art, the operating state of the rear axle drive motor of a four-wheel drive vehicle typically remains unchanged under different driving modes, which can easily lead to low rear axle drive motor efficiency, drag torque (torque generated by the rear wheels driving the motor), and power loss. In some embodiments of the present disclosure, different driving modes can be combined to implement corresponding gear control to reduce motor drag torque and power loss in related art.

[0087] In some embodiments of the present disclosure, at least one of the driving road information or the driving mode can be obtained using multiple implementation methods.

[0088] In some embodiments, step S11 includes: obtaining vehicle status information of a four-wheel drive vehicle; obtaining first information input by a user, the first information including: at least one of required driving mode information, required driving road information and required torque information; obtaining second information collected by an information acquisition device, the second information including: at least one of a driving road image or a driving road type; determining at least one of the driving road information or the driving mode based on at least one of the vehicle status information, the first information and the second information.

[0089] In such an embodiment, at least one of the traveling road information or the driving mode may be determined through at least one of the vehicle state information, the first information, and the second information.

[0090] In some embodiments, if only one piece of information is needed, only that piece of information may be acquired; if two pieces of information are needed, only the two pieces of information may be acquired. That is, it is not necessary to acquire all three pieces of information.

[0091] Vehicle status information may include information such as vehicle speed and throttle status. If only the vehicle status information is used to determine at least one of the driving road information or the driving mode, it can be regarded as a fuzzy judgment. For example, if the vehicle speed is fast (or the throttle force is 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 slow (or the throttle force is small), it can be determined that the road type traveled by the four-wheel drive vehicle is a special road type.

[0092] The first information may include required driving mode information, required driving road information, and required torque information; the first information may be understood as required information input by the user. For example, the user may input the first information through the vehicle computer.

[0093] If only the first information is used to determine at least one of the driving road information or the driving mode, 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; and at least one of the driving mode or the driving road information can be determined based on the required torque.

[0094] In some embodiments, if the required torque is medium, the driving mode may be a sport mode and the driving road information may be a special road type; if the required torque is small, the driving mode may be an energy-saving mode and the driving road information may be a non-special road type; if the required torque is large, the driving mode may be a standard driving mode and the driving road information may be a non-special road type.

[0095] The second information can be understood as 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. The driving road type can be directly determined by longitude and latitude positioning. Therefore, in some embodiments of the present disclosure, the driving road information can directly include information on the driving road type, and can also include information that can be used to determine the driving road type.

[0096] If at least one of the driving road information or the driving mode is determined based on only the second information, the driving road information can be determined based on the second information because both the driving road image and the driving road type belong to the driving road information.

[0097] For example, driving road features are extracted based on the driving road image, and driving road information is determined based on the driving road features; or, the driving road information directly obtained is determined as the final driving road information; or, the driving road information determined based on the driving road features and the driving road information directly obtained are integrated to determine the final driving road information.

[0098] In some embodiments, if more than two types of information are used to determine at least one of the driving road information or driving modes, the corresponding driving road information or at least one of the driving modes can be determined based on one piece of information respectively; then, the driving road information or at least one of the driving modes determined based on multiple pieces of information can be integrated to determine the final driving road information or at least one of the driving modes.

[0099] In some embodiments, at least one of the driving road information or the driving mode is determined based on at least one of the vehicle status information, the first information, and the second information, including: 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.

[0100] In such an embodiment, the driving road information may be determined in combination with the driving road image, the driving road type, the required driving road information, and the required torque; and the driving mode may be determined based on the required driving mode and the required torque.

[0101] For example, based on the driving road image, one type of driving road information can be determined; the driving road type can be determined as another type of driving road information; the required driving road information can be determined as another type of driving road information; and the required driving road information can also be determined based on the required torque. Then, it is determined whether at least two of these four types of driving road information are consistent. If so, the at least two consistent 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.

[0102] For example, the required driving mode can be used as a driving mode, and a driving mode can be determined based on the required torque. Then, it is determined whether the two driving modes are consistent. If so, either driving mode 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.

[0103] In some embodiments of the present disclosure, at least one of the driving road information or the driving mode can be determined through information of at least one dimension; and the information of at least one dimension is relatively easy to obtain, thereby enabling rapid and accurate determination of at least one of the driving road information or the driving mode.

[0104] In step S12, the rear-wheel drive gear position of the four-wheel drive vehicle is controlled according to at least one of the driving road information or the driving mode.

[0105] In some embodiments, a target gear position may be determined from multiple gear positions of a four-wheel drive vehicle based on at least one of the driving road information or the driving mode, and then the rear-wheel drive gear position of the four-wheel drive vehicle may be controlled to be the target gear position.

[0106] Figure 2 is a schematic diagram of a hybrid system architecture according to some embodiments. As shown in Figure 2, a four-wheel drive vehicle includes a front axle and a rear axle. The front axle is connected to two front wheels, namely, a left front wheel 302 and a right front wheel 301, through a differential 305; the rear axle is connected to two rear wheels, namely, a left rear wheel 304 and a right rear wheel 303, through a differential 305.

[0107] The front axle drive unit may include: an engine 104, a generator 101, a front axle drive motor 103, and a hybrid system transmission 102. The front axle drive motor 103 may be a single-speed drive motor. The rear axle drive unit may include: a rear axle drive motor 202 and a two-speed transmission 201. The rear axle drive motor 202 may be a multi-speed (P4) drive motor.

[0108] In the related art, for the rear axle drive part, the two-speed transmission 201 adopts a fixed transmission ratio to control the rear axle drive motor 202, so the rear axle drive motor 202 is equivalent to a single-speed drive motor; and in some embodiments of the present disclosure, the gear control of the rear axle drive motor 202 is added.

[0109] Furthermore, in some embodiments of the present disclosure, the rear-wheel drive gears of the four-wheel drive vehicle may include: first gear, second gear and third gear; the rear-wheel drive gears of the four-wheel drive vehicle may be understood as the gears of the rear axle drive motor 202.

[0110] The first gear can be N gear; when the rear-wheel drive of a four-wheel drive vehicle is in N gear, it means that the torque demand is low. At this time, the front axle drive motor 103 outputs torque, and the rear axle drive motor 202 does not output torque; the front axle drive motor 103 meets the driving needs of the entire vehicle, thereby reducing the drag torque and power loss of the rear axle reducer and the rear axle drive motor 202, thereby improving the economy and cruising range of the entire vehicle.

[0111] The second gear can be a high gear; when the rear-wheel drive of the four-wheel drive vehicle is in high gear, the front axle drive motor 103 and the rear axle drive motor 202 both continuously output torque, thereby improving the power and handling stability of the entire vehicle.

[0112] The third gear can be a low gear; when the rear-wheel drive of the four-wheel drive vehicle is in a low gear, both the front axle drive motor 103 and the rear axle drive motor 202 output torque, and the torque output by the rear axle drive motor 202 is a high torque (higher than the torque output by the high gear, and can meet the torque requirements of special driving roads), thereby improving the power and passability of the entire vehicle.

[0113] Furthermore, the rear axle drive motor 202 does not output torque in the first gear, and the torque output by the rear axle drive motor 202 in the second gear is smaller than the torque output by the rear axle drive motor 202 in the third gear.

[0114] Furthermore, the torque output by the rear axle drive motor 202 in the second gear can also be understood as being less than the preset torque. Furthermore, the torque output by the rear axle drive motor 202 in the third gear can also be understood as being greater than the preset torque. The preset torque can be greater than 0 and can serve as the gear dividing line between the second and third gears. If the torque output by the rear axle drive motor 202 is greater than the preset torque, the gear is in the third gear; if the torque output by the rear axle drive motor 202 is less than the preset torque, the gear is in the second gear.

[0115] Therefore, in some embodiments, controlling the gear position of the rear wheel drive of a four-wheel drive vehicle according to at least one of the driving road information or the driving mode may include: determining a target gear position from the first gear position, the second gear position, and the third gear position according to at least one of the driving road information or the driving mode, and controlling the gear position of the rear wheel drive of the four-wheel drive vehicle to the target gear position.

[0116] In some embodiments of the present disclosure, the driving road information can represent the driving road type of the four-wheel drive vehicle. Therefore, the implementation method of step S12 is introduced below based on at least one of the driving road type or driving mode represented by the driving road information.

[0117] In the first embodiment, the rear-wheel drive gear of the four-wheel drive vehicle may be controlled according to the driving road type. Accordingly, step S12 may include: if the driving road type is a target driving road type, determining a target gear from the second gear and the third gear, and controlling the rear-wheel drive gear of the four-wheel drive vehicle to be the target gear.

[0118] In some embodiments, the target driving road type may be a special road type in the aforementioned embodiments, that is, any road type among snow, sand, mountain, mud, wading, and rock.

[0119] It is understandable that when a four-wheel drive vehicle is traveling on these special roads, it requires a larger motor output torque. If only the front axle drive motor 103 outputs torque, it will not be able to meet the demand and may even easily cause various problems. Therefore, in this case, it is necessary to ensure the output torque of the rear axle drive motor, and then determine the target gear from the second gear and the third gear.

[0120] In some embodiments, the target gear is determined from the second gear and the third gear, including: if the target driving road type is snow or mud, the second gear is determined as the target gear; if the target driving road type is any one of sand, mountain and rock, the third gear is determined as the target gear.

[0121] It is understandable that if the road type is snow or mud, the vehicle needs a smaller torque to escape. Therefore, the rear axle drive motor 202 can run in a high gear, thereby improving the vehicle's power and handling stability.

[0122] If the road type is sandy, mountainous or rocky, the vehicle needs a particularly large torque to escape. Therefore, the rear axle drive motor 202 can be operated in a low gear, thereby improving the off-road performance and escape ability of the vehicle.

[0123] By judging the output torque requirement of the rear axle drive motor 202 based on the type of road being driven, the gear that meets the output torque requirement can be effectively and accurately determined, thereby improving the vehicle's power and handling stability while ensuring the need to escape from difficulties, reducing drag losses and improving off-road performance.

[0124] In some embodiments, the rear-wheel drive gear of the four-wheel drive vehicle can be controlled according to the driving mode. Accordingly, 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 202 in the second gear is less than the preset torque.

[0125] In this embodiment, the driving mode is the sport mode, which indicates a high demand for power and a need for continuous torque output. In this case, the rear axle drive motor 202 can be made to continuously output power torque to meet the high-power driving demand, allowing the four-wheel drive vehicle to travel at high speeds and improving the vehicle's power and handling stability.

[0126] By judging the output torque requirement of the rear axle drive motor 202 through the driving mode, the gear that meets the output torque requirement can be effectively and accurately determined, thereby improving the vehicle's power and handling stability while ensuring the need to escape from difficulties, reducing drag losses and improving off-road performance.

[0127] In some embodiments, the rear-wheel drive gear of the four-wheel drive vehicle may be controlled based on the driving road information and the driving model. Accordingly, 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 a target gear from the first gear and the second gear, and controlling the rear-wheel drive gear of the four-wheel drive vehicle to the target gear.

[0128] In this embodiment, since the road type does not match the target road type and the driving mode is either the energy-saving mode or the standard driving mode, the required torque output by the rear axle motor is relatively low. Therefore, a more economical gear can be selected from the first and second gears as the target gear, thereby improving vehicle power and handling stability while reducing power loss.

[0129] In some embodiments of the present disclosure, the target gear position may be determined based on an economical principle. The economical efficiency of the gear position may be assessed by the vehicle's electric drive power loss. The vehicle's electric drive power loss may be understood as the power loss of the vehicle's motor drive system.

[0130] Therefore, in some embodiments, determining a first vehicle electric drive power loss of a four-wheel drive vehicle in a first gear and determining a second vehicle electric drive power loss of the four-wheel drive vehicle in a second gear. Correspondingly, determining a target gear from the first gear and the second gear includes: determining the target gear from the first gear and the second gear based on the first vehicle electric drive power loss and the second vehicle electric drive power loss.

[0131] In some embodiments, the first vehicle electric drive loss power and the second vehicle electric drive loss power may be the loss power at corresponding vehicle speeds.

[0132] In some embodiments, the first vehicle electric drive loss power is determined based on the front axle information and the required torque of the vehicle motor drive. 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.

[0133] It can be understood that in the first gear, since the rear axle drive motor 202 does not output torque, the rear axle motor remains stationary during vehicle driving without loss such as drag, and the total required torque of the vehicle motor drive is output by the front axle drive motor.

[0134] For example, the first vehicle electric drive loss power can be expressed as:

[0135] Among them, P lossN Indicates power loss in N gear (i.e. first gear), P lossF Indicates the power loss of the front axle drive motor, T Req Indicates the required torque of the vehicle motor drive, n F Indicates the front axle drive motor speed, η F represents the efficiency of the front axle drive motor, i F Indicates the front axle reduction ratio.

[0136] In this embodiment, the front axle information and the required torque of the vehicle electric drive can be used to effectively and accurately determine the first vehicle electric drive loss power.

[0137] In some embodiments, 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 based on front axle information, rear axle information, torque demand ratio and vehicle motor drive demand torque, the front axle information includes: front axle drive motor speed, front axle drive motor efficiency and front axle reduction ratio, the rear axle information includes: rear axle drive motor speed, rear axle drive motor efficiency and 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.

[0138] It can be understood that in the second gear, the rear motor speed runs synchronously with the vehicle speed during driving, and outputs torque according to the torque distribution requirements of the front and rear axle motors. The total torque required for the vehicle's motor drive is jointly output by the front axle drive motor and the rear axle drive motor.

[0139] For example, the electric drive loss power of the second vehicle can be expressed as:

[0140] Among them, P lossH Indicates the power loss in high gear (i.e. second gear), P lossF Indicates the power loss of the front axle drive motor, n F Indicates the front axle drive motor speed, η F represents the efficiency of the front axle drive motor, i F Indicates the front axle reduction ratio, P lossR Indicates the power loss of the rear axle drive motor, n R Indicates the rear axle drive motor speed, η R Represents the efficiency of the rear axle drive motor, i R Indicates the rear axle reduction ratio, factor indicates the torque demand ratio, T Req Indicates the required torque of the vehicle's motor drive.

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

[0142] In addition, other information, such as efficiency, reduction ratio, etc., can be understood as known parameters and can be directly obtained.

[0143] Through the above embodiments, the first vehicle electric drive loss power and the second vehicle electric drive loss power can be effectively and accurately determined, and then based on the two powers, a more economical gear can be determined from the first gear and the second gear as the target gear.

[0144] Furthermore, determining a target gear from the first gear and the second gear based on 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 embodiment, the gear with the smallest power loss of the vehicle's electric drive is determined as the target gear, so that the target gear is more economical.

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

[0147] Therefore, in some embodiments, the target gear is determined from the first gear and the second gear based on the first vehicle electric drive loss power and the second vehicle electric drive loss power, including: determining the target gear from the first gear and the second gear based on 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.

[0148] Here, the maximum output torque of the front axle drive motor is a known parameter of the front axle drive motor 103 and can be directly obtained.

[0149] In some embodiments, 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 required torque and the front axle drive motor maximum output torque meet the preset relationship, the first gear is determined 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 required torque and the front axle drive motor maximum output torque do not meet the preset relationship, the second gear is determined as the target gear.

[0150] In some embodiments, the preset relationship is any one of the following: the required torque of the vehicle motor drive is less than or equal to the maximum output torque of the front axle drive motor; the required torque of the vehicle motor drive 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 when the drive motor switches.

[0151] In some embodiments, the preset torque is used to characterize the torque required when the drive motor is switched. By considering this torque, the untimely response during the gear switching of the rear axle drive motor can be avoided.

[0152] Therefore, the gear determination process can be expressed as follows: when P lossN ≤P lossH And T Req ≤(T Fwhole -Δt), the target gear is N; when P lossN >P lossH or T Req >(T Fwhole -Δt), the target gear is high gear. Fwhole It 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 meaning of other parameters can refer to the above embodiments.

[0153] Through this embodiment, a more reasonable target gear can be determined by combining the relationship between the required torque of the vehicle motor drive and the maximum output torque of the front axle drive motor, so that the target gear can meet both economic requirements and torque requirements.

[0154] In some embodiments, the rear-wheel drive gear of a four-wheel drive vehicle is controlled according to the driving road information and the driving mode, including: if the driving road type does not belong to the target driving road type and the driving mode is the sports mode, the second gear is determined as the target gear, and the rear-wheel drive gear of the four-wheel drive vehicle is controlled to be the target gear.

[0155] In this embodiment, if the road type does not match the target road type and the driving mode is Sport mode, indicating that the four-wheel drive vehicle has a high power demand and does not need to escape from a jam, requiring continuous torque output, the second gear can be determined as the target gear. This allows the rear axle drive motor to continuously output power torque to meet the high-power driving requirements, allowing the four-wheel drive vehicle to travel at high speeds and improving vehicle power and handling stability.

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

[0157] Figure 3 is a control flow chart of a four-wheel drive vehicle according to some embodiments. As shown in Figure 3, the vehicle's driving road information is first obtained, and then the user's needs and vehicle status are obtained; then, based on the road information and user needs, the target switching gear is determined; finally, the gear is switched according to the vehicle status.

[0158] FIG4 is a schematic diagram illustrating the relationship between vehicle speed and torque according to some embodiments. As shown in FIG4 , wheel-end torque involves three types of torque: 2H limit torque, 4H limit torque, and 4L limit torque. Here, 2H limit torque refers to the limit torque for N gear, 4H limit torque refers to the limit torque for high gear, and 4L limit torque refers to the limit torque for low gear. It can be seen that the limit torque for low gear is the highest. Furthermore, for N gear, there is a high-efficiency range within which power loss is low 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, 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 some embodiments of the present disclosure, it can be seen that, on the one hand, the technical solutions of some 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, some embodiments of the present disclosure also provide a control device for a four-wheel drive vehicle. FIG5 is a block diagram of a control device for a four-wheel drive vehicle according to some embodiments. As shown in FIG5 , the control device 500 for a four-wheel drive vehicle may include:

[0163] The acquisition module 501 is configured to: acquire at least one of the driving road information or the driving mode of the four-wheel drive vehicle;

[0164] The control module 502 is configured to control the rear-wheel drive gear of the four-wheel drive vehicle according to at least one of the driving road information or the driving mode. For example, at different gears, the rear axle drive motor of the four-wheel drive vehicle outputs different torques.

[0165] In some embodiments, the rear-wheel drive gears 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 smaller than the torque output by the rear axle drive motor in the third gear.

[0167] In some embodiments, 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, determining the target gear from the second gear and the third gear, and controlling the rear-wheel drive gear of the four-wheel drive vehicle to the target gear;

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

[0170] In some embodiments, 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, the third gear is determined as the target gear.

[0172] In some embodiments, the control module 502 is further configured to: if the driving mode is the 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 the preset torque.

[0173] In some embodiments, the driving mode is an energy-saving mode or a standard driving mode, a target gear is determined from the first gear and the second gear, and the rear-wheel drive gear of the four-wheel drive vehicle is controlled 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] In some embodiments, the control module 502 is further configured to: determine the first vehicle electric drive loss power of the four-wheel drive vehicle in the first gear; determine the second 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 based on the first vehicle electric drive loss power and the second vehicle electric drive loss power.

[0176] In some embodiments, the control module 502 is further configured to determine the first vehicle electric drive loss power based on the front axle information and the required torque of the vehicle motor drive, and 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.

[0177] In some embodiments, the control module 502 is further configured to: determine the second vehicle electric drive loss power based on 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.

[0178] In some embodiments, the control module 502 is further configured to: 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;

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

[0180] In some embodiments, the control module 502 is further configured to determine the target gear from the first gear and the second gear based on 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.

[0181] In some embodiments, the control module 502 is further configured to: determine the first 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, and the vehicle motor drive required torque and the maximum output torque of the front axle drive motor satisfy a preset relationship;

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

[0183] In some embodiments, the preset relationship is any one of the following:

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

[0185] The vehicle motor drive required 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 when the drive motor is switched.

[0186] In some embodiments, 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 the sports mode, determine the second gear as the target gear, and control the rear-wheel drive gear 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] In some embodiments, the acquisition module 501 is further configured to: acquire vehicle status information of the four-wheel drive vehicle;

[0188] Acquiring first information input by a user, the first information comprising at least one of required driving mode information, required driving road information, and required torque information;

[0189] Acquiring second information collected by the information collection device, the second information including: at least one of a driving road image or a driving road type;

[0190] The driving road information and / or the driving mode are determined based on at least one of the vehicle state information, the first information, and the second information.

[0191] In some embodiments, 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] The driving mode is determined according to the required driving mode and the required torque.

[0193] Figure 6 is a functional block diagram of a vehicle according to some embodiments. Referring to Figure 6 , vehicle 600 may include various subsystems. For example, vehicle 600 includes an infotainment system 610, a perception system 620, a decision control system 630, a drive system 640, and a computing platform 650. For example, vehicle 600 may include more or fewer subsystems, and each subsystem may include multiple components. Furthermore, each subsystem and each component of vehicle 600 may be interconnected via 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 surrounding the vehicle 600. For example, the perception system 620 may include a global positioning system (which may be a GPS system, a BeiDou system, or other positioning systems), an inertial measurement unit (IMU), a laser radar, a millimeter-wave radar, an ultrasonic radar, and a camera.

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

[0197] The drive system 640 may include components that provide power to the vehicle 600. In some embodiments, the drive system 640 may include an engine, an energy source, a transmission system, and wheels. The engine may be an internal combustion engine, an electric motor, an air compression engine, or a combination thereof. The engine is capable of converting energy provided by the energy source into mechanical energy.

[0198] Some or all functions of the vehicle 600 are controlled by a 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 type of processor, such as a commercially available CPU. The processor may also include a graphics processing 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 may be implemented by any type of volatile or non-volatile memory 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 disk.

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

[0202] In some embodiments of the present disclosure, the processor 651 may execute the instruction 653 to complete all or part of the steps of the above-mentioned four-wheel drive vehicle control method.

[0203] In other embodiments, a controller is also provided, which may be part of the aforementioned vehicle. The controller may be an integrated circuit (IC) or a chip. For example, the integrated circuit may be a single IC or a collection of multiple ICs. The chip may 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 aforementioned integrated circuit or chip may be used to execute executable instructions (or code) to implement the aforementioned four-wheel drive vehicle control method. The executable instructions may be stored in the integrated circuit or chip, or may 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 instruction can be stored in the memory, and when the executable instruction is executed by the processor, the above-mentioned four-wheel drive vehicle control method is implemented; alternatively, the integrated circuit or chip can receive the executable instruction through the interface and transmit it to the processor for execution, so as to implement the above-mentioned four-wheel drive vehicle control method.

[0204] Some embodiments of the present disclosure further provide a computer-readable storage medium having computer program instructions stored thereon, which, when executed by a processor, implement the steps of the four-wheel drive vehicle control method provided by the present disclosure.

[0205] Some embodiments of the present disclosure further provide a computer program product, which includes a computer program that can be executed by a programmable device, and has a code portion for executing the above-mentioned four-wheel drive vehicle control method when executed by the programmable device.

[0206] Any technical disclosure in this disclosure, as well as the recombination of multiple technical disclosures, can form a complete technical solution and can solve one or more of the above-mentioned technical problems and achieve the purpose of the invention. They all belong to the content of this disclosure and are the content that is directly and unambiguously determined based on the content of this disclosure.

[0207] Those skilled in the art will understand that the scope of the present invention is not limited to the above specific embodiments, and that certain elements of the embodiments may be modified and replaced without departing from the spirit of the present application. The scope of the present application is limited by the appended claims.

Claims

1. A method for controlling a four-wheel drive vehicle, wherein: The control method includes: obtaining at least one of driving road information or driving mode of the four-wheel drive vehicle; The rear-wheel drive gear of the four-wheel drive vehicle is controlled according to at least one of the driving road information 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 rear-wheel drive gears 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 smaller than the torque output by the rear axle drive motor in the third gear.

3. The control method according to claim 1 or 2, wherein: The driving road information is used to characterize the driving road type of the four-wheel drive vehicle; Controlling the rear-wheel drive gear 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 a target gear from the second gear and the third gear, and controlling the rear-wheel drive gear of the four-wheel drive vehicle to the target gear; The torque output by the rear axle drive motor in the second gear is smaller than the torque output by the rear axle drive motor in the third gear.

4. The control method according to claim 3, wherein: Determining the target gear position from the second gear position and the third gear position 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, the third gear is determined as the target gear.

5. The control method according to claim 1, wherein: Controlling the rear-wheel drive gear of the four-wheel drive vehicle according to the driving mode includes: 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.

6. 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 rear-wheel drive gear 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 energy-saving mode or the standard driving mode, determining a target gear from the first gear and the second gear, and controlling the rear-wheel drive gear of the four-wheel drive vehicle to 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 a preset torque.

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

8. The control method according to claim 7, wherein: The determining of a first vehicle electric drive loss power of the four-wheel drive vehicle in the first gear includes: The first vehicle electric drive loss power is determined based on front axle information and the vehicle motor drive required torque, wherein the front axle information includes: front axle drive motor speed, front axle drive motor efficiency and front axle reduction ratio.

9. The control method according to claim 7, wherein: The determining of the second vehicle electric drive loss power of the four-wheel drive vehicle in the second gear position includes: The second vehicle electric drive loss power is determined based on 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.

10. The control method according to claim 7, wherein: The determining the target gear position from the first gear position and the second gear position according to the first vehicle electric drive loss power and the second vehicle electric drive loss power includes: If the first vehicle electric drive power loss is greater than the second vehicle electric drive power loss, 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, the first gear is determined as the target gear.

11. The control method according to claim 7, wherein: The determining the target gear position from the first gear position and the second gear position according to the first vehicle electric drive loss power and the second vehicle electric drive loss power includes: The target gear is determined 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.

12. The control method according to claim 11, wherein: 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 vehicle motor drive required torque includes: 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 required torque and the maximum output torque of the front axle drive motor satisfy a preset relationship, the first gear is determined 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 required torque and the front axle drive motor maximum output torque do not satisfy the preset relationship, the second gear is determined as the target gear.

13. The control method according to claim 12, wherein: The preset relationship is any of the following: The vehicle motor drive required torque is less than or equal to the maximum output torque of the front axle drive motor; The vehicle motor drive required 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 when the drive motor is switched.

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 rear-wheel drive gear 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 sports mode, the second gear is determined as the target gear, and the rear-wheel drive gear of the four-wheel drive vehicle is controlled 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.

15. The control method according to any one of claims 1 to 14, wherein: The obtaining of at least one of the driving road information or the driving mode of the four-wheel drive vehicle includes: Obtaining vehicle status information of the four-wheel drive vehicle; Acquiring first information input by a user, the first information comprising at least one of required driving mode information, required driving road information, and required torque information; Acquiring second information collected by the information collection device, the second information including: at least one of a driving road image or a driving road type; At least one of the driving road information or the driving mode is determined based on at least one of the vehicle state information, the first information, and the second information.

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

17. A controller comprising: a memory having a computer program stored therein; and A processor is configured to execute the computer program in the memory so as to enable the controller to execute the control method for a four-wheel drive vehicle according to any one of claims 1 to 16.

18. A vehicle comprising the controller according to claim 17.

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

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