Control method and device for four-wheel drive vehicle, and vehicle

Abstract

A control method and device for a four-wheel drive vehicle, and a vehicle. The method comprises: if an auxiliary drive of a four-wheel drive vehicle meets a first forced coupling condition, controlling a wheel end decoupler of the auxiliary drive to switch from an unengaged state to an engaged state, wherein the first forced coupling condition comprises: the vehicle speed of the four-wheel drive vehicle is less than or equal to a first target vehicle speed and the wheel end decoupler is in the unengaged state. According to the technical scheme, when the vehicle speed of the vehicle is less than or equal to the first target vehicle speed and the wheel end decoupler of the auxiliary drive of the four-wheel drive vehicle is in the unengaged state, the wheel end decoupler of the auxiliary drive is controlled to switch from the unengaged state to the engaged state.

Description

Control method, device and vehicle of four-wheel drive vehicle

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to Chinese patent application number 202310694969.2, filed with the China Patent Office on June 12, 2023, entitled “Control method, device and vehicle for four-wheel drive vehicle,” the entire contents of which are incorporated by reference into this disclosure. Technical Field

[0003] The present disclosure relates to the field of vehicles, and in particular, to a control method and device for a four-wheel drive vehicle and the vehicle. Background Art

[0004] How to provide users with a better experience is always a concern for vehicle developers. They are also committed to improving vehicles to meet user needs.

[0005] Acceleration performance refers to a vehicle's ability to quickly increase its speed. Good acceleration performance not only provides users with a better driving experience but also improves road efficiency. Improving a vehicle's acceleration performance is a topic worthy of research.

[0006] Summary of the Invention

[0007] The purpose of the present disclosure is to provide a control method, device and vehicle for a four-wheel drive vehicle, which can improve the acceleration performance of the vehicle.

[0008] The present disclosure provides a control method for a four-wheel drive vehicle, comprising:

[0009] If the auxiliary drive of the four-wheel drive vehicle meets a first forced coupling condition, the wheel-end decoupler of the auxiliary drive is controlled to switch from a non-engaged state to an engaged state, wherein the first forced coupling condition includes: the vehicle speed of the four-wheel drive vehicle is less than or equal to a first target vehicle speed and the wheel-end decoupler is in a non-engaged state.

[0010] Optionally, the control method further includes:

[0011] If the auxiliary drive of the four-wheel drive vehicle meets the second forced coupling condition, the wheel-end decoupler is controlled to switch from a non-engaged state to an engaged state, wherein the second forced coupling condition includes: the vehicle speed of the four-wheel drive vehicle is greater than or equal to a second target vehicle speed and the wheel-end decoupler is in a non-engaged state, wherein the second target vehicle speed is greater than the first target vehicle speed.

[0012] Optionally, the control method further includes:

[0013] If the auxiliary drive of the four-wheel drive vehicle meets the coupling enabling condition, the wheel-end decoupler is allowed to be controlled to switch from a non-engaged state to an engaged state, wherein the coupling enabling condition includes: the speed difference between the connecting shafts at both ends of the wheel-end decoupler is less than a first target speed difference, and the output torque of the auxiliary drive is less than or equal to the target output torque.

[0014] Optionally, the control method further includes:

[0015] If the auxiliary drive of the four-wheel drive vehicle meets the decoupling enabling condition, the wheel-end decoupler is allowed to be controlled to switch from the engaged state to the disengaged state, wherein the decoupling enabling condition includes: the drive motor of the auxiliary drive of the four-wheel drive vehicle is not working, the speed of the four-wheel drive vehicle is greater than the first target speed and less than the second target speed, and the differential lock of the auxiliary drive of the four-wheel drive vehicle is in the disconnected state.

[0016] Optionally, the control method further includes:

[0017] If the auxiliary drive of the four-wheel drive vehicle meets the locking enable condition, the differential lock controlling the auxiliary drive is allowed to switch from the disconnected state to the locked state, wherein the locking enable condition includes: the vehicle speed of the four-wheel drive vehicle is less than the third target vehicle speed, the speed difference between the connecting shafts at both ends of the wheel-end decoupler is less than the second target speed difference, and the output torque of the auxiliary drive of the four-wheel drive vehicle is less than or equal to the target output torque.

[0018] Optionally, the first target speed difference is smaller than the second target speed difference.

[0019] Optionally, the control method further includes:

[0020] If the auxiliary drive of the four-wheel drive vehicle meets the unlocking enabling condition, the differential lock of the auxiliary drive is controlled to switch from a locked state to a disconnected state, wherein the unlocking enabling condition includes: receiving a differential lock unlocking instruction.

[0021] Optionally, the control method further includes:

[0022] When the vehicle speed is greater than a fourth target vehicle speed, generating the differential lock unlocking instruction;

[0023] Alternatively, the differential lock unlocking instruction is generated in response to receiving a trigger signal input by a user.

[0024] The present disclosure also provides a control device for a four-wheel drive vehicle, comprising a controller configured to execute the steps of the above-mentioned control method for the four-wheel drive vehicle.

[0025] The present disclosure further provides a vehicle, comprising a controller, which implements the steps of the above-mentioned four-wheel drive vehicle control method when executed.

[0026] In the above technical solution, when the vehicle speed is less than or equal to the first target speed and the auxiliary drive wheel-end decoupler of the four-wheel drive vehicle is in a disengaged state, the auxiliary drive wheel-end decoupler is controlled to switch from the disengaged state to the engaged state. On the one hand, when the vehicle speed is less than or equal to the first target speed, the difference in energy consumption during vehicle driving before and after the auxiliary drive wheel-end decoupler is engaged is not significant. On the other hand, because the auxiliary drive wheel-end decoupler is engaged when the vehicle speed is less than or equal to the first target speed, when the vehicle needs to accelerate, the engagement time of the wheel-end decoupler can be shortened, thereby improving the vehicle's acceleration performance and providing a better user experience.

[0027] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0029] FIG1 is a schematic structural diagram of an auxiliary drive of a four-wheel drive vehicle.

[0030] FIG2 is a flow chart showing a method for controlling a four-wheel drive vehicle according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0031] 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.

[0032] It should be noted that all actions of acquiring signals, information or data in the present disclosure are carried out in compliance with the corresponding data protection laws and policies of the country where they are located and with the authorization given by the owner of the corresponding device.

[0033] The control method for a four-wheel drive vehicle provided in the present disclosure can be applied to a four-wheel drive vehicle. For example, a vehicle using the control method for a four-wheel drive vehicle provided in the present disclosure may include two drive systems, a main drive system and an auxiliary drive system. In one embodiment, the main drive system of the vehicle is used to drive the two front wheels of the vehicle, and the auxiliary drive system of the vehicle is used to drive the two rear wheels of the vehicle. In another embodiment, the main drive system of the vehicle is used to drive the two rear wheels of the vehicle, and the auxiliary drive system of the vehicle is used to drive the two front wheels of the vehicle.

[0034] Figure 1 is a schematic diagram of the auxiliary drive system of a four-wheel drive vehicle. As shown in Figure 1 , the auxiliary drive system includes a drive motor 300, a wheel-end decoupler 840, a differential lock 850, wheels 100, a first axle shaft 500, a second axle shaft 400, a connecting shaft 450, a speed reducer 600, and a differential 700. The speed reducer 600 shown in Figure 1 includes a primary reduction driving gear 610, a primary reduction driven gear 620, a secondary reduction driving gear 630, and a secondary reduction driven gear 640. As shown in Figure 1 , a controller 200 can be used to control the drive motor 300, the wheel-end decoupler 840, and the differential lock 850 of the auxiliary drive system of the four-wheel drive vehicle. The controller 200 can control the operation or non-operation of the drive motor 300, the coupling or decoupling of the wheel-end decoupler 840 (i.e., switching the wheel-end decoupler between an engaged and disengaged state), and the locking or disengagement of the differential lock 850. The control method for a four-wheel drive vehicle provided by the present disclosure may be used on a four-wheel drive vehicle including an auxiliary drive as shown in FIG1 .

[0035] When the wheel-end decoupler 840 is engaged and the differential lock 850 is disengaged, the torque output by the drive motor 300 can be transmitted to the wheel 100 through the speed reducer 600 and the differential 700, enabling the drive motor 300 to drive the wheel 100. When the wheel-end decoupler 840 is engaged and the differential lock 850 is locked, the side gears within the differential 700 can be rigidly connected to the differential housing, allowing the connecting shafts at both ends of the wheel-end decoupler 840 to receive the torque output by the drive motor 300 at equal speeds. When the wheel-end decoupler 840 is in the disengaged state and the differential lock 850 is in the disconnected state, one of the wheels corresponding to the two ends of the wheel-end decoupler 840 is disconnected from the differential 700 and cannot continue to transmit power through the differential 700. The wheel on the other side drives the differential gear to idle, and the wheel cannot continue to drive the differential housing to rotate, thereby unable to drive the drive motor 300 to rotate. In this way, the wheel and the drive motor are decoupled, the drag torque of the reducer and the drive motor is eliminated, the drag torque of the vehicle is reduced, and the purpose of energy saving is achieved.

[0036] FIG2 is a flow chart showing a method for controlling a four-wheel drive vehicle according to an exemplary embodiment of the present disclosure. As shown in FIG2 , the method for controlling a four-wheel drive vehicle includes step S201 .

[0037] In step S201, if the auxiliary drive of the four-wheel drive vehicle meets the first forced coupling condition, the wheel-end decoupler of the auxiliary drive is controlled to switch from a disengaged state to an engaged state, wherein the first forced coupling condition includes: the speed of the four-wheel drive vehicle is less than or equal to the first target speed and the wheel-end decoupler is in a disengaged state.

[0038] The first target speed can be set to be fixed by a technician or set by a user. For example, the user can input and change the value of the first target speed through the vehicle screen. In one embodiment, the first target speed is 5km / h. When the vehicle is traveling, if the vehicle speed is low (less than the first target speed), and the vehicle is in a two-wheel drive state (i.e., driven by the main drive of a four-wheel drive vehicle) and the wheel-end decoupler of the auxiliary drive is in a disengaged state, the wheel-end decoupler of the auxiliary drive can be controlled to switch from a disengaged state to an engaged state. In this way, when the user controls the vehicle to accelerate, the wheel-end decoupler of the auxiliary drive of the four-wheel drive vehicle is already in an engaged state, which saves the time of controlling the engagement of the wheel-end decoupler and improves the acceleration performance of the vehicle.

[0039] In another embodiment, before or when the vehicle starts, when the wheel-end decoupler of the auxiliary drive of the four-wheel drive vehicle is in a disengaged state, when the speed of the four-wheel drive vehicle is less than or equal to the first target speed, the wheel-end decoupler of the auxiliary drive is controlled to switch from the disengaged state to the engaged state. For example, in one application scenario, after the vehicle starts, the user may operate the vehicle to drive out of the parking space. At this time, the vehicle speed is less than the first target speed and the wheel-end decoupler of the auxiliary drive of the vehicle is in a disengaged state. Although the vehicle's demand for driving force is not large at this time, the wheel-end decoupler of the auxiliary drive of the four-wheel drive vehicle can still be controlled to switch from the disengaged state to the engaged state. In this way, when the user controls the vehicle to accelerate and the vehicle's demand for driving force is large and the vehicle needs to switch from the two-wheel drive state to the four-wheel drive state, the wheel-end decoupler of the auxiliary drive of the four-wheel drive vehicle is already in the engaged state, saving the time of controlling the wheel-end decoupler to engage and improving the vehicle's acceleration performance.

[0040] In the above technical solution, when the vehicle speed is less than or equal to the first target speed and the auxiliary drive wheel-end decoupler of the four-wheel drive vehicle is in a disengaged state, the auxiliary drive wheel-end decoupler is controlled to switch from the disengaged state to the engaged state. On the one hand, when the vehicle speed is less than or equal to the first target speed, the difference in energy consumption during driving between before and after the engagement of the auxiliary drive wheel-end decoupler is not significant. On the other hand, because the auxiliary drive wheel-end decoupler is engaged when the vehicle speed is less than or equal to the first target speed, the engagement time of the wheel-end decoupler can be reduced when the vehicle needs to accelerate, thereby improving the vehicle's acceleration performance and providing a better user experience.

[0041] In yet another embodiment, the control method further includes:

[0042] If the auxiliary drive of the four-wheel drive vehicle meets the second forced coupling condition, the wheel-end decoupler is controlled to switch from a non-engaged state to an engaged state, wherein the second forced coupling condition includes: the vehicle speed of the four-wheel drive vehicle is greater than or equal to the second target vehicle speed and the wheel-end decoupler is in a non-engaged state, wherein the second target vehicle speed is greater than the first target vehicle speed.

[0043] The second target vehicle speed may be set by a technician based on experience or by a user. For example, in one embodiment, the second target vehicle speed is 150 km / h.

[0044] When the wheel-end decoupler of the auxiliary drive of a four-wheel drive vehicle is in a disengaged state, the output end of the auxiliary drive differential of the vehicle will be in an idling state. If the wheel-end decoupler of the auxiliary drive is in a disengaged state and the vehicle speed is high (such as the vehicle speed is greater than the second target speed), the output end of the auxiliary drive differential of the vehicle will be in a high-speed idling state, but the main reducer does not rotate and the lubricating oil cannot be thrown out, which may cause the differential to overheat or excessively wear. In order to avoid damage to the auxiliary drive differential of the vehicle, the technician can set the second target speed based on experience, and control the engagement of the wheel-end decoupler of the auxiliary drive of the vehicle when the vehicle speed is greater than or equal to the second target speed during the vehicle's driving.

[0045] In this embodiment, when the vehicle speed is greater than or equal to the second target speed, the wheel-end decoupler is forced to engage, thereby avoiding overheating or excessive wear of the differential due to high-speed idling of the differential output end, reducing the possibility of vehicle parts failure, and extending the service life of the vehicle.

[0046] It should be noted that, in one embodiment, the first forced coupling condition also includes the auxiliary drive motor of the four-wheel drive vehicle being in a non-working state. For example, when the four-wheel drive vehicle is traveling at a low speed in the two-wheel drive working state, when the auxiliary drive motor of the four-wheel drive vehicle is in a non-working state, the wheel-end decoupler of the auxiliary drive is in a non-engaged state, and the vehicle speed is less than or equal to the first target speed, the wheel-end decoupler of the auxiliary drive of the four-wheel drive vehicle can be controlled to switch from a non-engaged state to an engaged state. In this way, after the wheel-end decoupler of the auxiliary drive of the four-wheel drive vehicle is controlled to switch to the engaged state, when the user wants to control the acceleration of the vehicle, the engagement time of the wheel-end decoupler of the auxiliary drive of the vehicle is saved, so that the vehicle can quickly switch from the two-wheel drive working state to the four-wheel drive working state, thereby improving the acceleration performance of the vehicle and enhancing the user experience.

[0047] In yet another embodiment, the second forced coupling condition further includes the auxiliary drive motor of the four-wheel drive vehicle being in an inoperative state. For example, when the auxiliary drive motor of the four-wheel drive vehicle is in an inoperative state, the auxiliary drive wheel-end decoupler is in a disengaged state, and the vehicle speed is greater than or equal to the second target speed, the auxiliary drive wheel-end decoupler of the four-wheel drive vehicle can be controlled to switch from a disengaged state to an engaged state to prevent differential overheating or damage due to high-speed idling of the differential output end.

[0048] In yet another embodiment, the control method further includes:

[0049] If the auxiliary drive of the four-wheel drive vehicle meets the coupling enabling conditions, the wheel-end decoupler is allowed to be controlled to switch from the non-engaged state to the engaged state, wherein the coupling enabling conditions include: the speed difference between the connecting shafts at both ends of the wheel-end decoupler is less than the first target speed difference, and the output torque of the auxiliary drive is less than or equal to the target output torque.

[0050] Technicians can set the first target speed difference and target output torque based on experience. During vehicle driving, if the wheel-end decoupler is in a disengaged state and the auxiliary drive of the four-wheel drive vehicle does not meet the coupling enable condition, the engagement process of the wheel-end decoupler may not be smooth enough, which will bring a bad user experience. Therefore, in one embodiment, the auxiliary drive of the four-wheel drive vehicle is required to meet the coupling enable condition, and then the wheel-end decoupler of the auxiliary drive is controlled to engage. In one embodiment, the connecting shafts at both ends of the wheel-end decoupler may refer to the second half shaft 400 and the connecting shaft 450 at both ends of the wheel-end decoupler 840. The output torque of the auxiliary drive may be the torque output by the drive motor of the auxiliary drive.

[0051] It should be noted that, in one embodiment, if the auxiliary drive of a four-wheel drive vehicle satisfies the first forced coupling condition or the second forced coupling condition, the wheel-end decoupler of the auxiliary drive may be forced to switch from a non-engaged state to an engaged state. In other words, if the auxiliary drive of a four-wheel drive vehicle satisfies the first forced coupling condition or the second forced coupling condition, the wheel-end decoupler of the auxiliary drive may be forced to switch from a non-engaged state to an engaged state even if the auxiliary drive of the vehicle does not meet the coupling enablement condition.

[0052] If the auxiliary drive of the four-wheel drive vehicle does not meet the first forced coupling condition or the second forced coupling condition, the coupling enable condition needs to be met before the wheel-end decoupler is controlled to switch from the unengaged state to the engaged state. For example, in response to receiving a user-triggered instruction to control the coupling of the wheel-end decoupler of the auxiliary drive, the auxiliary drive of the four-wheel drive vehicle needs to meet the coupling enable condition before the wheel-end decoupler of the auxiliary drive is controlled to switch from the unengaged state to the engaged state. For another example, by judging the vehicle's driving conditions, when it is necessary to control the coupling of the wheel-end decoupler of the auxiliary drive of the vehicle (excluding the two situations where the auxiliary drive meets the first forced coupling condition and the auxiliary drive meets the second forced coupling condition), the wheel-end decoupler of the auxiliary drive is controlled to switch from the unengaged state to the engaged state only when the auxiliary drive of the vehicle meets the coupling enable condition.

[0053] In this embodiment, when the auxiliary drive of the four-wheel drive vehicle meets the coupling enabling conditions, the wheel-end decoupler is allowed to switch from the non-engaged state to the engaged state. This makes the engagement process of the wheel-end decoupler smoother and provides a better user experience.

[0054] In yet another embodiment, the control method further includes:

[0055] If the auxiliary drive of the four-wheel drive vehicle meets the decoupling enabling conditions, the wheel-end decoupler is allowed to switch from the engaged state to the disengaged state, wherein the decoupling enabling conditions include: the drive motor of the auxiliary drive of the four-wheel drive vehicle is not working, the speed of the four-wheel drive vehicle is greater than the first target speed and less than the second target speed, and the differential lock of the auxiliary drive of the four-wheel drive vehicle is in the disconnected state.

[0056] When the auxiliary drive motor of a four-wheel drive vehicle is operating, the torque output by the drive motor needs to be used to drive the wheels. Therefore, the wheel-end decoupler must remain engaged to allow the wheels to be driven by the drive motor. To prevent the resistance of one wheel end from still being transmitted to the motor after the wheel-end decoupler is decoupled (i.e., the wheel-end decoupler switches from an engaged state to a disengaged state), in one embodiment, the wheel-end decoupler is only allowed to decouple when the differential lock of the auxiliary drive of the four-wheel drive vehicle is in a disengaged state.

[0057] For example, in response to receiving a user-triggered instruction to control the decoupling of the auxiliary drive wheel-end decoupler, the auxiliary drive of the four-wheel drive vehicle must meet a decoupling enable condition before the auxiliary drive wheel-end decoupler is controlled to switch from an engaged state to a disengaged state. For another example, based on a determination of the vehicle's driving conditions, if the auxiliary drive wheel-end decoupler needs to be decoupled, the auxiliary drive wheel-end decoupler is controlled to switch from an engaged state to a disengaged state only when the auxiliary drive meets the decoupling enable condition.

[0058] If the wheel-end decoupler is in the engaged state, but the auxiliary drive of the four-wheel drive vehicle does not meet the decoupling enabling condition, the wheel-end decoupler is not allowed to be controlled to switch from the engaged state to the disengaged state.

[0059] In this embodiment, when the wheel-end decoupler of the auxiliary drive of a four-wheel drive vehicle is engaged and the auxiliary drive of the four-wheel drive vehicle meets the decoupling enabling conditions, the wheel-end decoupler is controlled to switch from the engaged state to the disengaged state. This optimizes the control logic for controlling the decoupling of the wheel-end decoupler, and decoupling of the wheel-end decoupler is only allowed when the drive motor of the auxiliary drive is not operating, thereby avoiding energy waste.

[0060] In yet another embodiment, the control method further includes:

[0061] If the auxiliary drive of the four-wheel drive vehicle meets the locking enable conditions, the differential lock controlling the auxiliary drive is allowed to switch from the disconnected state to the locked state, wherein the locking enable conditions include: the vehicle speed of the four-wheel drive vehicle is less than the third target vehicle speed, the speed difference between the connecting shafts at both ends of the wheel-end decoupler is less than the second target speed difference, and the output torque of the auxiliary drive of the four-wheel drive vehicle is less than or equal to the target output torque.

[0062] In one embodiment, the third target vehicle speed is lower than the first target vehicle speed. As the vehicle speed decreases from the first target vehicle speed, the wheel-end decoupler is forced to engage. Thus, the differential lock is not allowed to engage until the vehicle speed continues to decrease below the third target vehicle speed, thereby avoiding a situation where the wheel-end decoupler is not engaged but the differential is locked.

[0063] The difference between the third target vehicle speed and the second target speed can be set by technicians based on experience. To ensure a smoother transition from the disengaged to the locked state of the auxiliary drive differential lock, the differential lock is only allowed to switch from the disengaged to the locked state when the speed difference between the connecting shafts at both ends of the wheel-end decoupler is less than the second target speed difference and the output torque of the auxiliary drive of the four-wheel drive vehicle is less than or equal to the target output torque.

[0064] For example, in response to receiving a user-triggered instruction to lock the auxiliary drive differential lock, the auxiliary drive of the four-wheel drive vehicle must meet a lock enable condition before the auxiliary drive differential lock is controlled to switch from a disengaged state to a locked state. For another example, if the vehicle's driving conditions determine that the auxiliary drive differential lock needs to be locked, the auxiliary drive differential lock is controlled to switch from a disengaged state to a locked state only when the auxiliary drive meets the lock enable condition.

[0065] If the auxiliary drive of the four-wheel drive vehicle does not meet the lock enabling conditions, the differential lock of the auxiliary drive is not allowed to lock.

[0066] In this embodiment, the differential lock is controlled to lock only when the auxiliary drive of the four-wheel drive vehicle meets the locking enabling condition, thereby improving the smoothness of the differential lock locking.

[0067] In yet another embodiment, the first target rotational speed difference is smaller than the second target rotational speed difference.

[0068] The speed difference between the connecting shafts at both ends of the wheel-end decoupler is less than a first target speed difference, which is one of the conditions that must be met to control the wheel-end decoupler to switch from an unengaged state to an engaged state. To ensure smooth power switching, the speed difference between the connecting shafts at both ends of the wheel-end decoupler cannot be too large. Therefore, in one embodiment, the first target speed difference is set to a small value. Based on the above ideas, technicians can set a specific value for the first target speed difference based on experience. The speed difference between the connecting shafts at both ends of the wheel-end decoupler is less than a second target speed difference, which is one of the conditions that allows the auxiliary drive differential lock to switch from a disengaged state to a locked state. When the auxiliary drive differential lock of a four-wheel drive vehicle needs to be locked, the vehicle is often in a state that can be close to a stationary state. At this time, the user is mentally prepared for the fact that the speed difference between the connecting shafts at both ends of the wheel-end decoupler may be large. Therefore, when the speed difference between the connecting shafts at both ends of the wheel-end decoupler is relatively large (greater than the first target speed difference and less than the second target speed difference), the differential lock is controlled to lock, which can ensure the safety of the vehicle.

[0069] In this embodiment, the first target speed difference is smaller than the second target speed difference, which optimizes the control logic of the auxiliary drive of the four-wheel drive vehicle and can provide users with a better user experience.

[0070] In yet another embodiment, the control method further includes:

[0071] If the auxiliary drive of the four-wheel drive vehicle meets the unlocking enabling condition, the differential lock of the auxiliary drive is controlled to switch from a locked state to a disconnected state, wherein the unlocking enabling condition includes: receiving a differential lock unlocking instruction.

[0072] When the auxiliary drive of a four-wheel drive vehicle meets the unlocking enabling conditions, the differential lock of the auxiliary drive can be controlled to switch from a locked state to a disconnected state. In this way, the differential lock is avoided from being locked when it is required to be in a disconnected state, thereby improving the safety of vehicle use.

[0073] In yet another embodiment, the control method further includes:

[0074] When the vehicle speed is greater than a fourth target vehicle speed, generating a differential lock unlocking instruction;

[0075] Alternatively, in response to receiving a trigger signal input by a user, a differential lock unlocking instruction is generated.

[0076] While the vehicle is in motion, if the differential lock is engaged and the vehicle's speed exceeds a certain speed, steering becomes difficult, posing a safety hazard. To ensure safe driving, a differential lock unlock command can be generated when the vehicle's speed exceeds this speed, switching the auxiliary drive differential lock from locked to disengaged. When setting the fourth target speed, this speed can be determined as the fourth target speed. The specific value of the fourth target speed can be determined by technicians based on experience.

[0077] When a trigger signal input by the user is received, it means that the user desires to switch the differential lock from the locked state to the disconnected state. In order to ensure the driving safety of the vehicle, a differential lock unlocking instruction can be generated to control the differential lock of the auxiliary drive of the vehicle to switch from the locked state to the disconnected state.

[0078] In this embodiment, when the vehicle speed is greater than the fourth target speed or a trigger signal input by the user is received, a differential lock unlocking instruction is generated. In this way, the differential lock of the auxiliary drive can be controlled to switch from a locked state to a disconnected state to ensure vehicle driving safety.

[0079] The present disclosure further provides a control device for a four-wheel drive vehicle. The control device for a four-wheel drive vehicle includes a controller configured to execute the steps of the above-mentioned control method for a four-wheel drive vehicle.

[0080] The present disclosure also provides a vehicle, which includes a controller, and when the controller is executed, the steps of the above-mentioned four-wheel drive vehicle control method are implemented.

[0081] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within 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 scope of protection of the present disclosure.

[0082] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0083] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A control method for a four-wheel drive vehicle, characterized in that: include: If the auxiliary drive of the four-wheel drive vehicle meets the first forced coupling condition, the wheel-end decoupler of the auxiliary drive is controlled to switch from a disengaged state to a engaged state, wherein the first forced coupling condition includes: the vehicle speed of the four-wheel drive vehicle is less than or equal to a first target vehicle speed and the wheel-end decoupler is in a disengaged state.

2. The control method according to claim 1, characterized in that: The control method further comprises: If the auxiliary drive of the four-wheel drive vehicle meets the second forced coupling condition, the wheel-end decoupler is controlled to switch from a disengaged state to an engaged state, wherein the second forced coupling condition includes: the vehicle speed of the four-wheel drive vehicle is greater than or equal to a second target vehicle speed and the wheel-end decoupler is in a disengaged state, wherein the second target vehicle speed is greater than the first target vehicle speed.

3. The control method according to claim 1 or 2, characterized in that: The control method further comprises: If the auxiliary drive of the four-wheel drive vehicle meets the coupling enable condition, the wheel-end decoupler is allowed to be controlled to switch from a non-engaged state to an engaged state, wherein the coupling enable condition includes: the speed difference between the connecting shafts at both ends of the wheel-end decoupler is less than the first target speed difference, and the output torque of the auxiliary drive is less than or equal to the target output torque.

4. The control method according to any one of claims 1 to 3, characterized in that: The control method further comprises: If the auxiliary drive of the four-wheel drive vehicle meets the decoupling enabling condition, the wheel-end decoupler is allowed to be controlled to switch from the engaged state to the disengaged state, wherein the decoupling enabling condition includes: the drive motor of the auxiliary drive of the four-wheel drive vehicle is not working, the vehicle speed of the four-wheel drive vehicle is greater than the first target speed and less than the second target speed, and the differential lock of the auxiliary drive of the four-wheel drive vehicle is in the disconnected state.

5. The control method according to claim 3, characterized in that: The control method further comprises: If the auxiliary drive of the four-wheel drive vehicle meets the locking enable condition, the differential lock controlling the auxiliary drive is allowed to switch from a disconnected state to a locked state, wherein the locking enable condition includes: the vehicle speed of the four-wheel drive vehicle is less than a third target vehicle speed, the speed difference between the connecting shafts at both ends of the wheel-end decoupler is less than a second target speed difference, and the output torque of the auxiliary drive of the four-wheel drive vehicle is less than or equal to the target output torque.

6. The control method according to claim 5, characterized in that: The first target rotation speed difference is smaller than the second target rotation speed difference.

7. The control method according to any one of claims 1 to 6, characterized in that: The control method further comprises: If the auxiliary drive of the four-wheel drive vehicle meets the unlocking enabling condition, the differential lock of the auxiliary drive is controlled to switch from a locked state to a disconnected state, wherein the unlocking enabling condition includes: receiving a differential lock unlocking instruction.

8. The control method according to claim 7, characterized in that: The control method further comprises: When the vehicle speed is greater than a fourth target vehicle speed, generating the differential lock unlocking instruction; or, In response to receiving a trigger signal input by a user, the differential lock unlocking instruction is generated.

9. A control device for a four-wheel drive vehicle, characterized in that: The method comprises a controller configured to execute the steps of the method according to any one of claims 1 to 8.

10. A vehicle, characterized in that: The method comprises a controller, wherein when the controller is executed, the steps of the method according to any one of claims 1 to 8 are implemented.

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