A control method and control device of a differential lock, a vehicle and a storage medium

Abstract

The application relates to the technical field of vehicle transmission control, in particular to a control method and device of a differential lock, a vehicle and a computer readable storage medium, the method comprising the following steps: in response to a first instruction for starting the differential lock, an actual temperature of an excitation coil is acquired; a target locking torque of the differential lock is acquired; the target locking torque is matched with a current driving condition of the vehicle; based on the actual temperature and the target locking torque, a first driving current required by the differential lock for generating the target locking torque at the actual temperature is determined; and the differential lock is controlled to be locked based on the first driving current.

Description

Technical Field

[0001] This application relates to the field of vehicle transmission control technology, specifically to a differential lock control method, control device, vehicle, and computer-readable storage medium. Background Technology

[0002] The main function of a differential lock is to force the left and right drive wheels to rotate synchronously under specific operating conditions, in order to prevent loss of traction due to slippage of one wheel. This technology is widely used in vehicles such as off-road vehicles and sedans that operate in complex road conditions, to achieve reasonable power distribution.

[0003] Differential locks typically include a field coil. The field coil is the core component of the differential lock actuator; it generates electromagnetic force when energized to drive the driving gear and engaging gear, thus achieving the locking function of the differential. When power is off, the differential lock unlocks using a return spring. Conventional techniques typically use a fixed drive current to power the field coil when activating the differential lock, neglecting the significant impact of temperature on the electromagnetic performance of the field coil. For example, when the field coil temperature is high, the resistance increases, and the magnetic force decreases, potentially causing the differential lock to fail to lock completely, posing a safety hazard. Summary of the Invention

[0004] One objective of this application is to provide a differential lock control method to solve the safety hazard of the inability to completely lock in the existing control methods; a second objective is to provide a control device; a third objective is to provide a vehicle; a fourth objective is to provide a computer-readable storage medium; and a fifth objective is to provide a computer program.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows: This application provides a differential lock control method, including: in response to a first command to activate the differential lock, acquiring the actual temperature of the excitation coil; acquiring the target locking torque of the differential lock; matching the target locking torque with the current driving conditions of the vehicle; determining, based on the actual temperature and the target locking torque, a first driving current required for the differential lock to generate the target locking torque at the actual temperature; and controlling the differential lock to lock based on the first driving current.

[0006] Based on the aforementioned technical methods, the system first responds to the initial command to activate the differential lock by acquiring the actual temperature of the excitation coil and determining the target locking torque in conjunction with the current driving conditions. Then, based on this temperature-torque relationship, a suitable drive current is calculated to achieve precise locking. This approach considers both the impact of temperature on the performance of the electromagnetic coil, optimizing the drive current through temperature compensation to improve the locking success rate, and matching the target locking torque under different driving conditions to ensure the differential lock operates more safely and effectively, preventing hardware damage due to misoperation or unsuitable conditions.

[0007] In some embodiments, obtaining the actual temperature of the excitation coil includes: obtaining the actual resistance value of a temperature-sensitive resistor installed in the differential lock near the excitation coil, and determining the actual temperature of the excitation coil based on the actual resistance value and the temperature change characteristics of the temperature-sensitive resistor; or, obtaining the oil temperature in the differential of the vehicle, and determining the actual temperature of the excitation coil based on the oil temperature; the temperature of the excitation coil is positively correlated with the oil temperature; the differential lock is located in the differential.

[0008] Based on the aforementioned technical methods, the excitation coil temperature is estimated using either a temperature-sensitive resistor or the differential oil temperature, ensuring high measurement accuracy and low cost. This allows for adaptation to different hardware configurations and enhances flexibility.

[0009] In some embodiments, determining the first drive current required for the differential lock to generate the target locking torque at the actual temperature based on the actual temperature and the target locking torque includes: determining the first drive current based on the actual temperature, the target locking torque, and a first mapping relationship; wherein the first mapping relationship characterizes the correspondence between the temperature of the excitation coil, the locking torque of the differential lock, and the drive current.

[0010] Based on the aforementioned technical methods, the optimal drive current is obtained by bilinear interpolation calculation using a preset three-dimensional mapping table of temperature-target torque-current setpoints. This approach comprehensively considers the influence of multiple factors on the drive current, improving control accuracy, while also reducing the latency caused by complex model calculations and enhancing response speed.

[0011] In some embodiments, determining a first drive current required for the differential lock to generate the target locking torque at the actual temperature, based on the actual temperature and the target locking torque, includes: determining a reference drive current required for the differential lock to generate the target locking torque at a reference temperature, based on the target locking torque; determining a magnetic performance attenuation coefficient based on the actual temperature of the excitation coil; determining the actual resistance of the excitation coil at the actual temperature, based on the actual temperature of the excitation coil; and determining the first drive current based on the magnetic performance attenuation coefficient, the actual resistance, and the reference drive current.

[0012] Based on the aforementioned technical methods, a fuzzy computation model is used for current compensation, taking into account the influence of core material characteristics and coil resistance changes on the current output, thereby dynamically adjusting the drive current. This approach maintains a constant locking torque under different temperature conditions, improving control stability; furthermore, it eliminates the need for complex lookup tables, reducing storage requirements.

[0013] In some embodiments, the method further includes: in response to detecting that the vehicle is in a slipping state, outputting a first prompt message to instruct the driver to operate a target switch to activate the differential lock; receiving the driver's operation on the target switch and generating a first instruction.

[0014] Based on the aforementioned technical means, when vehicle slippage is detected, the system proactively prompts the driver to use the differential lock function, assisting them in operating it correctly. This improves driver efficiency and reduces misoperation, while also enhancing the applicability of the differential lock in challenging situations and improving the driver's experience.

[0015] In some embodiments, obtaining the actual temperature of the excitation coil includes: if the differential lock is in the unlocked state, controlling the power supply circuit of the differential lock to be turned on and obtaining the actual temperature of the excitation coil; if the differential lock is in the locked state, outputting a second prompt message to indicate that the differential lock has been activated.

[0016] Based on the aforementioned technical methods, the decision to acquire temperature data is made by determining the differential lock status, thus avoiding unnecessary operations. This reduces unnecessary power consumption and extends equipment lifespan; furthermore, status prompts enhance the driver's interactive experience.

[0017] In some embodiments, if the differential lock is in an unlocked state, obtaining the actual temperature of the excitation coil includes: obtaining a first driving parameter of the vehicle; if the differential lock is in an unlocked state and the first driving parameter meets a first condition, then obtaining the actual temperature of the excitation coil; the method further includes: if the differential lock is in an unlocked state and the first driving parameter does not meet the first condition, then outputting a third prompt message indicating that the differential lock cannot be activated. The first condition is related to at least one of the following: the vehicle's accelerator pedal opening, the vehicle's speed, the wheel speed difference between the left and right wheels of the vehicle, and the vehicle's steering angle.

[0018] Based on the aforementioned technical methods, the suitability of obtaining temperature data is determined by analyzing driving parameters, further enhancing safety. This serves two purposes: firstly, it prevents the differential lock from being triggered under unsuitable operating conditions, avoiding potential risks; secondly, it guides the driver to operate appropriately through prompts, improving user-friendliness.

[0019] In some embodiments, after controlling the differential lock to lock based on the drive current, the method further includes: acquiring a second driving parameter of the vehicle and / or a first actual current of the differential lock; determining whether the locking condition is met based on the second driving parameter and / or the first actual current of the differential lock; if the locking condition is met, setting the state of the differential lock to a locked state and outputting a fourth prompt message indicating that the differential lock is locked; if the locking condition is not met, controlling the state of the differential lock to an unlocked state and outputting a fifth prompt message indicating that the differential lock is not locked.

[0020] Based on the aforementioned technical methods, the success of locking is determined by real-time monitoring of driving parameters and current status, thereby improving closed-loop control capabilities. This ensures stable operation of the differential lock under suitable conditions, improving reliability, and enhances the driver's understanding of the operating status through status feedback.

[0021] In some embodiments, after controlling the differential lock to be in a locked state, the method further includes: acquiring a third driving parameter of the vehicle; if the third driving parameter satisfies a third condition, controlling the differential lock to unlock; if the third driving parameter satisfies a fourth condition, maintaining the locked state of the differential lock based on a second driving current; the second driving current is less than the first driving current. The third condition is related to at least one of the vehicle speed, the vehicle steering angle, and the wheel speed difference between the left and right wheels of the vehicle; the fourth condition is related to at least one of the vehicle speed, the wheel speed difference between the left and right wheels of the vehicle, and the wheel steering angle.

[0022] Based on the aforementioned technical methods, the differential lock state is dynamically adjusted through driving parameters, balancing energy saving and safety. This allows for switching to a lower current mode when continuous high current is not required, reducing energy consumption; and also enables flexible adjustment of the locking state according to operating conditions, improving adaptability.

[0023] In some embodiments, the method further includes: controlling the differential lock to unlock in response to a second command to release the differential lock.

[0024] Based on the aforementioned technical means, drivers are allowed to actively disengage the differential lock, enhancing operational flexibility. This facilitates timely disengagement of the differential lock in scenarios such as high speeds or cornering, ensuring driving safety; furthermore, it enhances controllability through explicit instructions.

[0025] In some embodiments, controlling the differential lock to unlock includes: setting the differential lock drive current to a preset value; the method further includes: acquiring a second actual current of the differential lock; if the second actual current meets a second preset condition, setting the state of the differential lock to an unlocked state, and outputting a sixth prompt message; wherein the sixth prompt message represents the reason why the differential lock has been unlocked and / or the reason for the differential lock unlocking; if the second actual current does not meet the second preset condition, setting the state of the differential lock to a fault state, and outputting a seventh prompt message indicating a differential lock fault.

[0026] Based on the aforementioned technical methods, the reliability of the differential lock is improved by determining whether it is truly unlocked through the current status. This prevents the differential lock from failing to unlock properly due to hardware malfunctions, thus avoiding safety hazards; furthermore, it enhances the driver's awareness of the status through prompts.

[0027] In some embodiments, after setting the differential lock to an unlocked state, the method further includes: acquiring a fourth driving parameter of the vehicle; if the fourth driving parameter meets a fifth condition, controlling the power supply circuit of the differential lock to be disconnected; if the fourth driving parameter does not meet the fifth condition, setting the differential lock to a fault state, and outputting a seventh prompt message indicating a differential lock fault; the fifth condition is related to the vehicle speed, the vehicle steering angle, and the wheel speed difference between the left and right wheels of the vehicle.

[0028] Based on the aforementioned technical methods, determining whether it is appropriate to disconnect the power supply circuit using driving parameters further enhances safety. This reduces unnecessary energy consumption and extends equipment lifespan; furthermore, it enhances self-diagnostic capabilities through fault indication, thereby improving overall reliability.

[0029] This application provides a control device for a differential lock, comprising: a first acquisition unit for acquiring the actual temperature of the excitation coil in response to a first command to activate the differential lock; a second acquisition unit for acquiring the target locking torque of the differential lock, wherein the target locking torque is matched with the current driving conditions of the vehicle; a determination unit for determining, based on the actual temperature and the target locking torque, a first drive current required for the differential lock to generate the target locking torque at the actual temperature; and a control unit for controlling the differential lock to lock based on the first drive current.

[0030] This application provides a vehicle, including: a differential lock and a control device; the control device includes one or more processors and a memory; the memory is used to store one or more programs, which, when executed by one or more processors, cause the device to implement the method described above.

[0031] This application provides a computer-readable storage medium storing a computer program thereon, which, when executed by a computer's processor, causes the computer to perform the above-described method.

[0032] The beneficial effects of this application are as follows: On the one hand, this application considers the influence of temperature on the performance of the electromagnetic coil and optimizes the drive current through temperature compensation, thereby improving the locking success rate; on the other hand, by matching the target locking torque under different driving conditions, the differential lock can work more safely and effectively, avoiding hardware damage caused by misoperation or unsuitable conditions. Attached Figure Description

[0033] Figure 1 This is a schematic diagram illustrating the result of a differential lock provided in an embodiment of this application; Figure 2 A flowchart illustrating a differential lock control method provided in an embodiment of this application; Figure 3 A schematic diagram of a vehicle speed lock control system provided in an embodiment of this application; Figure 4 A flowchart illustrating another differential lock control method provided in an embodiment of this application; Figure 5 A flowchart illustrating a control and detection method for a differential lock provided in an embodiment of this application; Figure 6 This is a schematic diagram of the structure of a differential lock control device provided in an embodiment of this application; Figure 7 A schematic diagram of the structure of a vehicle provided in an embodiment of this application; Figure 8 This is a schematic diagram of the structure of a differential lock control device provided in an embodiment of this application. Detailed Implementation

[0034] The embodiments of this application will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be understood that the preferred embodiments are only for illustrating this application and are not intended to limit the scope of protection of this application.

[0035] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. Therefore, the drawings only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0036] Before providing a further detailed description of the embodiments of this application, the nouns and terms used in the embodiments of this application are explained, and the nouns and terms used in the embodiments of this application shall be interpreted as follows: 1) Excitation coil: This is the core component of the differential lock actuator. When energized, it generates electromagnetic force to couple the drive gear and engagement gear, thus achieving the locking function of the differential. When power is off, the differential lock unlocks using a return spring. The performance of the excitation coil is significantly affected by temperature; therefore, the drive current needs to be adjusted according to the actual temperature to ensure the locking effect. The excitation coil can also be referred to as an electromagnetic coil.

[0037] 2) Target locking torque: This refers to the minimum locking torque required by the differential lock under the current driving conditions. This torque is determined by the controller based on parameters such as vehicle speed, wheel speed difference, and throttle opening to ensure that the differential lock can complete the locking operation under appropriate conditions, avoiding impact on driving safety or equipment lifespan due to excessive or insufficient locking.

[0038] 3) Drive current: This refers to the current applied to the excitation coil, and its magnitude directly affects the locking torque of the differential lock. Since the resistance of the excitation coil and the characteristics of the magnetic core material change with temperature, a temperature compensation strategy must be considered when determining the drive current to ensure that the expected locking effect can be achieved under different ambient temperatures.

[0039] 4) Locking conditions: These refer to a set of driving parameters that meet the differential lock locking requirements, including but not limited to vehicle speed, wheel speed difference between the left and right drive wheels, steering angle, and throttle opening. The differential lock locking process will only be initiated when all these conditions are met simultaneously, in order to avoid using the differential lock under unsuitable operating conditions, thereby improving the safety and reliability of the system.

[0040] 5) Temperature Compensation Strategy: This is a method of adjusting the drive current based on the actual temperature of the excitation coil to counteract the effects of increased coil resistance and decreased magnetic core performance caused by temperature rise. This application proposes two compensation methods: one is a three-dimensional mapping table calibrated based on bench tests; the other is dynamic estimation based on a fuzzy calculation model. Both methods can effectively improve the locking success rate of differential locks under extreme temperature environments.

[0041] 6) Fault diagnosis mechanism: This refers to a series of detection logics set up in the differential lock control system to identify abnormal states of the system hardware or software, such as switch sticking, relay short circuit, signal loss, etc. Once a fault is detected, the system will automatically take corresponding protective measures (such as disconnecting the power supply, illuminating the fault light, etc.) and prompt the driver to handle the situation to prevent the differential lock from operating under abnormal conditions, thereby ensuring driving safety.

[0042] 7) Multi-signal closed-loop control: This refers to a system that not only relies on driver button input but also comprehensively acquires various driving parameters (such as vehicle speed, wheel speed difference, steering angle, throttle opening, etc.) as the basis for judgment, forming a closed-loop feedback to more accurately control the locking and unlocking process of the differential lock. This method eliminates the need for traditional physical status switches, saving hardware costs.

[0043] 8) Automatic Lock-up Reminder: This function automatically prompts the driver to try using the differential lock to get out of trouble when the vehicle is in a slippery state (such as low vehicle speed, large wheel speed difference, or high throttle opening). This function helps guide the driver to use the differential lock properly, improves the efficiency of getting out of trouble, and reduces the risk of misoperation.

[0044] This application provides a differential lock control method, control device, vehicle, and computer-readable storage medium, aiming to solve problems in existing differential lock control such as unsafety, slow response, lack of consideration for temperature effects, and lack of fault diagnosis mechanisms. By determining whether locking or unlocking the differential lock is appropriate based on actual vehicle driving parameters and introducing an electromagnetic coil temperature compensation strategy, the drive current is optimized, improving locking reliability and safety. Simultaneously, this application employs multi-signal closed-loop control to achieve more intelligent and safer differential lock control.

[0045] The following description, in conjunction with the accompanying drawings and specific embodiments, introduces a differential lock control method, control device, vehicle, and computer-readable storage medium provided in this application. The differential lock control method provided in this application is applied to a vehicle including a differential lock and can be executed by a controller in the vehicle.

[0046] In this embodiment, the differential lock may include a locked state, a locked transition state, an unlocked transition state, an unlocked state, and a fault state.

[0047] The locked state indicates that the differential lock is engaged. If the differential lock mechanism is fully engaged, the excitation coil outputs corresponding electromagnetic force to maintain engagement, and the left and right drive wheels are forced to synchronize. The lock-up transition state refers to the dynamic transition process where, after the controller receives the lock command, the excitation coil begins to be energized and the current increases from 0 to the first drive current, and the locking mechanism moves from the disengaged state to the engaged state. In the lock-up transition state, the actual current of the excitation coil continues to rise, the electromagnetic force gradually increases, the locking mechanism is in the process of engagement (not fully engaged), and the wheel speed difference between the left and right drive wheels gradually decreases. The unlocking transition state refers to the dynamic transition process where, after the controller receives the unlock command, the excitation coil drive current decays towards 0, the electromagnetic force gradually dissipates, and the locking mechanism moves from the engaged state to the disengaged state. The unlocking state is when the differential lock mechanism is fully disengaged, the excitation coil is de-energized, there is no electromagnetic force, the return spring resets, and the left and right drive wheels can independently adjust their speeds. The fault state indicates a differential lock malfunction.

[0048] In this embodiment, the differential lock includes an excitation coil, which is used to convert electrical energy into electromagnetic force to drive the differential lock to lock. Figure 1 This is a schematic diagram of a differential lock provided in an embodiment of this application.

[0049] like Figure 1 As shown, the differential lock 100 includes a engagement tooth 1, a drive tooth 2, an electromagnet 3, a sliding sleeve 4, and a return spring 5. The electromagnet 3 includes components such as an excitation coil and an iron core assembly. The excitation coil is wound around the outside of the iron core assembly, forming a coaxial assembly structure. When current is applied to the excitation coil, a closed magnetic field is formed inside, generating a directional electromagnetic force. This electromagnetic force acts on the iron core assembly, providing driving force for the subsequent action of the actuator. Figure 1As shown, electromagnet 3 is connected to sliding sleeve 4. Specifically, the iron core assembly in electromagnet 3 is connected to sliding sleeve 4. When the excitation coil is energized, it generates electromagnetic force, which acts on the iron core assembly. The iron core assembly pushes the sliding sleeve 4 axially, thereby driving the active tooth 2 to couple with the engagement tooth 1, achieving differential lock locking, and compressing the return spring 5. The active tooth 2 and engagement tooth 1 constitute the locking structure in the differential lock. When it is necessary to release the differential lock, electromagnet 3 is de-energized, and the return spring 5 pushes the active tooth 2 and engagement tooth 1 to disengage, achieving differential lock unlocking. It can be seen that the excitation coil is the core component in the differential lock actuator. By generating electromagnetic force through energization, it drives the active tooth and engagement tooth to couple, thereby achieving the locking function. Conventional technology uses a fixed current value to drive the excitation coil. When the temperature is high, the permeability of the iron core decreases with increasing temperature, resulting in a reduction in magnetic force. This may cause the differential lock to fail to lock completely, thus failing to provide sufficient locking torque. At the same time, high temperature will increase the resistance of the excitation coil, reduce the actual driving current, and cause the magnetic force to weaken. This will also cause the differential lock to fail to lock completely, and thus fail to provide sufficient locking torque.

[0050] Figure 2 This is a flowchart illustrating a differential lock control method provided in an embodiment of this application, as shown below. Figure 2 As shown, the method includes: S101, in response to the first command to activate the differential lock, obtains the actual temperature of the excitation coil.

[0051] The first command is used to activate the differential lock.

[0052] In some embodiments, the first command may be issued by the driver. For example, the driver may issue the first command via at least one of several methods, such as a physical button, a virtual button on the in-vehicle display, or an in-vehicle microphone. Taking a physical button as an example, the vehicle's central control area may be equipped with a physical button, which, in response to the driver's triggering operation on the physical button, generates the first command.

[0053] For example, the driver can actively issue the first command, such as when the driver needs to use the differential lock.

[0054] For example, when the controller detects that the vehicle is in a slipping state, it prompts the driver to use the differential lock. Specifically, in response to detecting that the vehicle is in a slipping state, the controller outputs a first prompt message instructing the driver to operate a target switch to engage the differential lock. It receives the driver's operation on the target switch and generates a first command. The target switch can be a physical button or a virtual button as described above. The physical switch can be, for example, a physical button, a physical knob, a physical paddle, a physical slider, etc. In some embodiments, the physical switch can also be, for example, a combination physical switch.

[0055] In this embodiment, the controller may be, for example, a differential lock controller. The differential lock controller is coupled to multiple sensors in the vehicle, can acquire data from the sensors, and execute different control processes based on the acquired data.

[0056] First combine Figure 3 This application introduces a differential lock control system provided by an embodiment. For example,... Figure 3 As shown, the control system includes a differential lock controller 310, a differential lock switch 320, a differential lock 330, an instrument 340, and an indicator light 350.

[0057] The differential lock controller 310 receives vehicle operating data and the switching signal from the differential lock switch 320, runs the control program, and executes the main control functions. The operating data may include, for example, one or more of the following: vehicle speed, wheel speed difference between the left and right drive wheels, left wheel speed validity signal, right wheel speed validity signal, steering angle, oil temperature, accelerator pedal opening, actual electromagnet current, and gradient. The differential lock switch 320 is the target switch mentioned earlier. Simultaneously, the differential lock controller 310 is connected to the differential lock 330 to control its locking and unlocking. For example, the differential lock controller 310 can output the differential lock's drive current and relay control signals. The differential lock controller 310 is connected to the instrument panel 340, which receives control signals from the differential lock controller 310 and displays corresponding prompts on the instrument panel based on these signals. The differential lock controller 310 is connected to the indicator light 350, which receives control signals from the differential lock controller 310 and switches its state accordingly.

[0058] In this embodiment, the controller determines that the vehicle is in a slippery state in response to detecting that the vehicle's driving parameters meet preset conditions. These preset conditions may include, for example, one or more of the following: the vehicle speed is less than a preset speed for a duration exceeding a preset duration; the difference between the speeds of the left and right wheels is greater than or equal to a preset difference for a duration exceeding a preset duration; or the accelerator pedal opening is greater than or equal to a preset opening for a duration exceeding a preset duration. The preset duration may be, for example, 2 seconds or 1 second; the preset speed is between [3 km / h, 5 km / h]; the preset difference is between [10 km / h, 20 km / h]; and the preset accelerator pedal opening is between [30%, 50%]. In other words, in this embodiment, the controller can continuously and periodically acquire the vehicle's driving parameters at a preset frequency and determine the vehicle's state based on these parameters. When the vehicle's driving parameters meet the preset conditions, it is determined that the vehicle is in a state where it wants to move, but its actual traction is insufficient, and its power is being consumed by slippery conditions. The controller can output a primary prompt message to instruct the driver to operate the target switch to engage the differential lock.

[0059] Slippage refers to a situation where a vehicle, due to insufficient road traction or other reasons, causes one or both wheels to spin freely, preventing effective power transmission. Slippage frequently occurs in complex road conditions such as mud, ice, snow, or steep slopes. When a vehicle is slipping, a conventional differential will transfer all power to the slipping wheel instead of the wheel with better traction. This can prevent the vehicle from moving forward and may even damage the differential. Due to these issues, the application of a differential lock in this situation can effectively solve the problem of improper power transmission.

[0060] The first prompt message is a visual or auditory prompt issued by the controller to guide the driver in operating the differential lock. The controller can output the first prompt message through at least one of the following methods: voice, text, light, and sound effects. For example, the controller may control the instrument panel to display the text message "Please try using the differential lock to get out of trouble."

[0061] In this embodiment, the controller receives the driver's operation on the target switch and can generate a first instruction. For example, the controller can verify the driver's operation, and generate the first instruction after the verification is successful. In other embodiments, the first instruction can be automatically issued by the vehicle. For example, in response to detecting that the vehicle is in a skidding state, the controller automatically generates the first instruction.

[0062] In this embodiment, when the vehicle is detected to be slipping, a first prompt message is output to guide the driver to operate the target switch to activate the differential lock. This improves the accuracy and safety of differential lock use, thereby reducing the failure to get out of trouble or equipment damage caused by misuse or non-use of the differential lock, and thus improving the vehicle's ability to pass through complex road conditions and the driving experience.

[0063] In this embodiment of the application, in response to the first instruction, the controller can first obtain the actual temperature of the excitation coil. The controller can obtain the actual temperature of the excitation coil in at least two ways.

[0064] One method involves the controller acquiring the actual temperature of the excitation coil based on the actual resistance value of a temperature-sensitive resistor installed near the excitation coil within the differential lock. The temperature-sensitive resistor is an electronic component whose resistance changes with temperature and is used for temperature measurement. Common types include negative temperature coefficient (NTC) thermistors and positive temperature coefficient (PTC) thermistors; this application preferably uses NTC thermistors because they exhibit good sensitivity and non-linear characteristics over a wide temperature range. The temperature-sensitive resistor is typically installed near the excitation coil to accurately reflect its operating temperature. For example, the resistor may be wound inside the excitation coil or on its frame. Exemplarily, the controller acquires the actual resistance value of the temperature-sensitive resistor and determines the actual temperature of the excitation coil based on this value and the resistor's temperature-dependent characteristics. For instance, the controller determines the actual resistance value by measuring the voltage and current of the temperature-sensitive resistor. Based on the temperature-resistance characteristic curve of the resistor, the controller determines the actual temperature corresponding to the actual resistance value, which can be used to characterize the actual temperature of the excitation coil. The temperature-resistance characteristic curve is pre-calibrated to indicate the mapping relationship between the resistance value of the temperature-sensitive resistor and temperature. This mapping relationship could be, for example, 25℃ corresponding to 10kΩ, 50℃ to 5kΩ, and 80℃ to 2kΩ. The advantage of this method is that it eliminates the need for an additional temperature sensor, utilizing only the temperature sensitivity of the temperature-sensitive resistor itself for temperature monitoring, thus reducing implementation complexity and cost. Furthermore, because the temperature-sensitive resistor is physically close to the excitation coil, it can more accurately reflect the operating state of the excitation coil, improving control precision.

[0065] Another method involves the controller determining the actual temperature of the excitation coil based on the temperature of the oil in the differential. The differential lock is located inside the differential. Oil temperature refers to the temperature of the lubricating oil inside the differential. Because the excitation coil is located inside the differential and is greatly affected by the surrounding environment, its temperature changes with the oil temperature. There is a positive correlation between the excitation coil temperature and the oil temperature; that is, as the oil temperature increases, the excitation coil temperature also increases. By acquiring oil temperature data and combining it with historical test data to establish a mapping relationship between oil temperature and excitation coil temperature, the controller can indirectly calculate the excitation coil temperature. For example, if the oil temperature is 60℃, according to experimental calibration, the excitation coil temperature is approximately 70℃. The advantage of this second method is that oil temperature sensors are usually already installed in the vehicle, eliminating the need for additional wiring or hardware, thus improving integration and reliability. Furthermore, since the oil temperature reflects the overall thermal state of the differential, it better reflects the long-term thermal load of the excitation coil.

[0066] S102, obtain the target locking torque of the differential lock.

[0067] In this embodiment, the target locking torque refers to the minimum locking torque required by the differential lock under the current driving state to ensure that the differential lock can reliably lock the left and right drive wheels and prevent slippage.

[0068] In some embodiments, the target locking torque is a preset value. In other embodiments, the target locking torque is matched to the vehicle's current driving condition. That is, the target locking torque is determined by the controller based on the vehicle's current driving condition. For example, the controller determines the current driving condition based on current road surface data and / or the vehicle's current driving parameters. Road surface data includes, but is not limited to, slip ratio, road surface type such as ice, water accumulation, gravel, etc., and road surface adhesion coefficient. Driving parameters include, but are not limited to, vehicle speed, gradient, steering angle, and wheel speed difference between the left and right drive wheels. For example, driving conditions can be categorized into low-adhesion road surface traction conditions, low-adhesion road surface climbing conditions, medium-adhesion road surface traction conditions, medium-adhesion road surface climbing conditions, high-adhesion road surface traction conditions, and high-adhesion road surface climbing conditions. The vehicle pre-stores a one-to-one mapping relationship between different driving conditions and different locking torques. The controller can determine the target locking torque corresponding to the current driving condition based on the vehicle's current driving condition and the pre-calibrated mapping relationship. As another example, the controller inputs road surface data and / or driving parameters, which characterize the current driving conditions, into a preset model, which can output a matching target locking torque. This model can be, for example, a neural network model.

[0069] After obtaining the actual temperature of the excitation coil and the target locking torque currently required by the vehicle, the controller can determine the first drive current based on the actual temperature and the target locking torque. The method also includes step S103.

[0070] S103, based on the actual temperature and the target locking torque, determines the first drive current required for the differential lock to generate the target locking torque at the actual temperature.

[0071] The first drive current is the current applied to the excitation coil. The magnitude of this first drive current directly determines the electromagnetic force generated by the electromagnet in the differential lock, thus affecting the locking torque of the differential lock. However, because the resistance of the excitation coil and the properties of the magnetic core material change with temperature, the required drive current will vary for the same target locking torque. For example, at -20℃, a differential lock may require 8.8A of drive current to generate a target locking torque of 1000Nm; at 20℃, it may require 10A; and at 80℃, it may require 12.5A. It can be seen that the differential lock requires different drive currents to generate the same locking torque at different temperatures. Furthermore, the higher the temperature, the greater the drive current required to generate the same locking torque. To this end, the controller determines the first drive current required for the differential lock to generate the target locking torque at the actual temperature, and drives the differential lock based on the first drive current. This stabilizes the electromagnetic force output by the excitation coil, ensuring that the differential lock outputs the target locking torque and meets the usage requirements.

[0072] In some embodiments, the controller determines the first drive current based on a pre-calibrated first mapping relationship. This first mapping relationship is a pre-stored three-dimensional data table. It characterizes the correspondence between the temperature of the excitation coil, the locking torque of the differential lock, and the drive current. Established experimentally or through calibration, the first mapping relationship describes the drive current required to achieve a specific locking torque at different temperatures. It considers the influence of coil resistance changes with temperature, as well as factors such as the decrease in magnetic flux density due to temperature variations in the core material properties. The decrease in magnetic flux density due to changes in core material properties affects the output characteristics of the electromagnet. The first mapping relationship ensures that a suitable current is output under different operating conditions to achieve a stable and reliable locking effect.

[0073] The first mapping relationship can be, for example, a first mapping table, which can be as shown in Table 1.

[0074] Table 1

[0075] For example, at low temperatures, the coil resistance is lower, allowing for a larger current to be provided at the same voltage, thus generating a stronger magnetic attraction. However, at high temperatures, due to increased resistance, the drive current must be increased to achieve the same locking torque. Based on the first mapping relationship, the controller combines the real-time acquired actual temperature and the set target locking torque, consults a table, and performs data interpolation to ultimately determine the first drive current, thereby achieving precise control of the motor.

[0076] In this embodiment, by introducing a first mapping relationship, the drive current can be dynamically adjusted according to the real-time temperature, thereby more accurately meeting the locking requirements, avoiding insufficient current or overload problems caused by temperature changes, and thus improving the response accuracy and stability of the differential lock.

[0077] In other embodiments, the controller determines the first drive current based on preset calculation logic. For example, the controller first determines the reference drive current required for the differential lock to generate the target locking torque at a reference temperature based on the target locking torque, and then corrects the reference drive current using the actual temperature to obtain the first drive current.

[0078] Specifically, the controller determines the reference drive current required for the differential lock to generate the target locking torque at the reference temperature based on the target locking torque. The reference temperature refers to a set reference temperature (e.g., 20℃) used as a calculation reference point. Under the reference temperature conditions, the various parameters of the electromagnet (e.g., resistance, permeability, etc.) are in an ideal state. Through bench testing, under the reference temperature conditions, the corresponding reference drive current Iref can be obtained according to the target locking torque Mt. This reference drive current Iref is the drive current that enables the differential lock to generate the target locking torque Mt at the reference temperature. The reference drive current Iref can also be calculated using formula (1).

[0079] , formula (1).

[0080] Where Mt is the target locking torque; K is the torque current coefficient at the reference temperature; excitation coils made of different materials correspond to different torque current coefficients at the same reference temperature. For example, the torque current coefficient of a copper coil at 20 degrees Celsius is 10 Nm / A².

[0081] Next, the controller determines the magnetic performance attenuation coefficient based on the actual temperature of the excitation coil. The excitation coil is a key component in the differential lock actuator. As the temperature increases, the permeability decreases, and the saturation magnetic induction intensity also decreases, resulting in a reduction in the magnetic flux generated by the same current, which affects the locking torque. The magnetic performance attenuation coefficient Km(T) is used to describe the proportion of decrease in magnetic performance relative to a reference temperature at a specific temperature T. For example, the magnetic performance attenuation coefficient Km(T) can be calculated using formula (2).

[0082] , formula (2).

[0083] Where T is the actual temperature of the excitation coil; The reference temperature is, for example, 20℃. It is the temperature coefficient of magnetic flux density of the electromagnet core material, such as -0.0012 / ℃ for electrical pure iron.

[0084] Next, the controller determines the actual resistance of the excitation coil at the actual temperature based on the actual temperature of the excitation coil. The actual resistance refers to the resistance value of the excitation coil at the actual temperature T. Taking the coil material as an example, since copper wire has a positive temperature coefficient, the resistance of the copper wire increases when the temperature rises. Under a fixed voltage supply, the increase in the resistance of the copper wire will lead to a decrease in the current, thereby weakening the output torque of the electromagnet. Therefore, the actual resistance must be dynamically calculated according to the actual temperature in order to make more accurate current regulation. For example, the actual resistance Rt of the excitation coil at the actual temperature can be calculated using formula (3).

[0085] , formula (3).

[0086] in, The reference resistance of the excitation coil at a reference temperature, such as 20°C; It is the temperature coefficient of resistance of the excitation coil at a reference temperature. Taking a copper coil as an example, the temperature coefficient of resistance of a copper coil at a reference temperature such as 20℃ is approximately 0.00393 / ℃.

[0087] Finally, the controller determines the first drive current based on the magnetic performance attenuation coefficient, actual resistance, and reference drive current. The first drive current refers to the final current after temperature compensation of the reference current, comprehensively considering the effects of magnetic performance attenuation, resistance changes, and other factors. This first drive current is used to drive the differential lock to lock. The first drive current not only meets the target locking torque requirement but also takes into account the nonlinear effects of temperature changes, ensuring reliable operation under extreme weather or long-term operating conditions. This application integrates information from the magnetic performance attenuation coefficient, actual resistance, and reference current to calculate a first drive current with higher accuracy and robustness, maintaining stable operation of the differential lock under complex conditions and effectively preventing locking failure or overload problems caused by temperature fluctuations. For example, the controller can first determine the first compensation current after magnetic performance compensation based on the reference drive current and the magnetic performance attenuation coefficient. For example, the controller uses formula (4) to determine the first compensation current after magnetic performance compensation. .

[0088] , formula (4).

[0089] Next, the controller compensates for the first compensation current based on the actual resistance to obtain the first drive current. For example, the controller uses formula (5) for the first drive current. .

[0090] , formula (5).

[0091] This embodiment introduces parameters such as reference temperature, reference drive current, magnetic attenuation coefficient, and actual resistance, and applies these parameters to the calculation of the first drive current. This technique enables adaptive compensation for temperature changes, ensuring stable locking of the differential lock under various environmental conditions, further enhancing the vehicle's passability and driving safety in special road conditions.

[0092] After obtaining the first drive current based on the above method, the controller can execute S104.

[0093] S104 controls the differential lock to lock based on the first drive current.

[0094] For example, after determining the first drive current, the controller supplies power to the excitation coil according to the value of the first drive current. The controller energizes the electromagnet in the differential lock, which in turn drives the differential lock's drive gear to couple with the engagement gear, thereby achieving the locking function. Due to the thrust generated by the energized electromagnet, the return spring of the differential lock is compressed, and the differential lock is in a closed state. The differential lock adjusts the speed of the left and right drive wheels to be the same, and the power is evenly distributed to the two drive wheels, thereby helping the vehicle get out of trouble or improving its passability.

[0095] For example, the controller first activates the differential lock's power supply circuit, such as by closing a relay. Once the circuit is activated, the controller sets the target value of the differential lock's drive current to the first drive current. The controller's high-current drive port begins outputting drive current to the differential lock. At this time, the actual current of the differential lock increases, and the controller sends a control signal to the indicator light, causing the instrument panel indicator light to flash green, indicating to the driver that the differential lock is locking. The flashing lasts for at least 3 seconds. After the controller's output current continues to rise to the first drive current, it maintains a stable constant current drive at the first drive current level.

[0096] In practical implementation, precise control of the first drive current is crucial for the locking effect of the differential lock. If the first drive current is too small, the locking torque may be insufficient, resulting in ineffective locking; if the first drive current is too large, it may cause the excitation coil to overheat, or even damage the excitation coil. Therefore, by calculating the first drive current based on the actual temperature of the excitation coil and the target locking torque, fine-grained control of the differential lock locking process can be achieved, thereby improving reliability and safety.

[0097] The differential lock control method provided in this application obtains the actual temperature of the excitation coil, determines the target locking torque in combination with the current driving conditions, and further calculates a suitable first driving current, thereby achieving precise control of the differential lock locking process.

[0098] In some embodiments, in response to a first command to activate the differential lock, the controller can first determine the current state of the differential lock. If the differential lock is in the unlocked state, it controls the power supply circuit of the differential lock to be turned on and obtains the actual temperature of the excitation coil. The differential lock being in the unlocked state indicates that it is not currently activated, meaning the differential lock is functioning normally, and the left and right wheels can freely rotate at different speeds. When the differential lock is in the unlocked state, the electromagnet is not energized, the sliding sleeve is separated from the drive gear, and the return spring keeps the differential lock in a non-coupled state. Turning on the power supply circuit of the differential lock means controlling the relay to close; for example, the controller sends a signal to the relay to close the relay contacts, thereby turning on the power supply circuit of the differential lock.

[0099] When the vehicle's differential lock is engaged, a second notification message is output to indicate that the differential lock is active. This second notification message informs the driver that the vehicle's differential lock is engaged. The controller can output the second notification message through at least one of the following methods: voice, text, light, or sound effects. For example, the controller can control the instrument panel to display the text message "Differential lock engaged." If the driver has already engaged the differential lock, in response to the driver's subsequent engagement, a notification message indicating that the differential lock is engaged can be output, informing the driver that the differential lock is engaged and the corresponding functions can be used directly.

[0100] In some embodiments, when the differential lock is in the unlocked state, before the controller acquires the actual temperature of the excitation coil and controls the differential lock to lock based on that actual temperature, the controller may also acquire the vehicle's first driving parameters through multiple sensors deployed in the vehicle, and determine whether the vehicle's first driving parameters meet a first condition. The first condition may be the operating condition of the differential lock; the differential lock will only be activated if it is met, and will not be activated if it is not met. That is, if the differential lock is in the unlocked state and the vehicle's first driving parameters meet the first condition, the controller will acquire the actual temperature of the excitation coil and control the differential lock to lock based on that actual temperature. If the differential lock is in the unlocked state and the vehicle's first driving parameters do not meet the first condition, the controller will not acquire the actual temperature of the excitation coil, and the controller will output a third prompt message indicating that the differential lock cannot be used.

[0101] The first driving parameter refers to the condition used to determine whether the differential lock can be engaged. The first driving parameter is at least one of the following: accelerator pedal opening, vehicle speed, left and right drive wheel speeds, and steering wheel angle.

[0102] The first condition is related to at least one of the following: accelerator pedal opening, vehicle speed, wheel speed difference between the left and right wheels, and steering angle. The left and right wheels can be the left and right drive wheels, and the steering angle can be represented by the steering wheel angle. The first condition includes at least one of the following: accelerator pedal opening is greater than or equal to a first opening threshold; vehicle speed is less than or equal to a first speed threshold; the difference between the wheel speeds of the left and right drive wheels is less than or equal to a first difference threshold; and steering wheel angle is less than or equal to a first angle threshold. The first opening threshold is taken from [30%, 50%], the first speed threshold is taken from [3km / h, 5km / h], the first difference threshold is taken from [3km / h, 5km / h], and the first angle threshold is taken from [90°, 120°].

[0103] Excessive accelerator pedal opening can cause gear grinding during differential lock coupling, affecting hardware lifespan and system safety. Engaging the differential lock at excessive speeds, with significant speed differences between the left and right drive wheels, or with excessive steering wheel angles, can severely compromise vehicle stability, damage the transmission system, and even lead to loss of control. Therefore, the controller must ensure that certain driving parameters meet specific conditions before initiating the differential lock engagement process to prevent these hazards.

[0104] If the first driving parameters do not meet the first condition, the controller can notify the driver via a third prompt message that the differential lock cannot be used. The controller can output the third prompt message through at least one of the following methods: voice, text, light, and sound effects. For example, the controller can control the instrument panel to display the text message "The operating conditions of the differential lock are not met. Please slow down and stop, straighten the steering wheel, and then engage the differential lock."

[0105] In this embodiment, by introducing a mechanism for collecting and judging the first driving parameters, the vehicle's operating status can be accurately identified, thereby improving the accuracy and safety of differential lock intervention. This can effectively avoid the risks caused by forcibly activating the differential lock under unsuitable conditions, thereby reducing hardware damage and improving vehicle reliability and driver experience.

[0106] In some embodiments, when the controller drives the differential lock to lock based on the first drive current, the differential lock switches from the unlocked state to a locking transition state. During the locking transition state, the actual current of the excitation coil continuously increases, the electromagnetic force gradually increases, the locking mechanism is in the process of engagement (not fully engaged), and the wheel speed difference between the left and right drive wheels gradually decreases. After the locking mechanism is fully engaged, the differential lock enters the locked state. In this embodiment, the controller can determine whether the differential lock has entered the locked state based on the vehicle's driving parameters and / or the actual current of the differential lock.

[0107] For example, the controller can acquire the vehicle's second driving parameters through multiple sensors deployed in the vehicle, and it can also acquire the first actual current of the differential lock. For instance, the controller can connect a high-precision sampling resistor in series in the excitation coil power supply circuit, collect the voltage drop across the sampling resistor, and calculate the first actual current of the differential lock excitation coil using Ohm's law, based on the fixed resistance value of the sampling resistor. Alternatively, the controller can utilize the Hall effect, using a Hall sensor located in the power supply circuit of the excitation coil to detect the magnetic field strength of the excitation coil power supply circuit and calculate the first actual current.

[0108] The controller determines whether the locking conditions are met based on the second driving parameter and / or the first actual current of the differential lock. If the locking conditions are met, the controller determines that the vehicle differential lock is locked. If the locking conditions are not met, the controller determines that the differential lock is not locked. The locking conditions are used to determine whether differential lock coupling has been completed, and typically include a comprehensive judgment of multiple parameters such as vehicle speed, wheel speed difference, steering wheel angle, and throttle opening. For example, when the wheel speed difference between the left and right drive wheels is less than a set value, the vehicle speed is below a certain threshold, and the steering angle does not exceed the limit range, the controller determines that the differential lock is locked.

[0109] In some embodiments, the locking condition includes at least one of the following: a second driving parameter of the vehicle satisfies a second condition, and a first actual current of the differential lock satisfies a first preset condition. Satisfying the locking condition can be understood as the second driving parameter of the vehicle satisfying the second condition and / or the first actual current of the differential lock satisfying the first preset condition.

[0110] The second driving parameter includes the wheel speed difference between the left and right drive wheels. The second condition is related to the wheel speed difference between the left and right wheels of the vehicle. The second condition is that the wheel speed difference between the left and right drive wheels is less than or equal to a second difference threshold. Alternatively, the second condition is that the wheel speed difference between the left and right drive wheels is less than or equal to the second difference threshold and lasts for a duration greater than or equal to a preset duration, such as 2 seconds or 1 second. If the second driving parameter meets the second condition, the differential lock is engaged. The acquisition time of the second driving parameter is later than the acquisition time of the first driving parameter. The second difference threshold is taken from [1 km / h, 2 km / h].

[0111] The first preset condition is that the first actual current of the differential lock is greater than the first preset current value, or the first preset condition is that the first actual current of the differential lock is greater than the first preset current value and the duration is greater than or equal to a preset duration, such as 2 seconds or 1 second. The first preset current value is slightly less than the first drive current value, such as first preset current value = (first drive current value - preset difference). When the first actual current of the differential lock meets the first preset condition, it indicates that the differential lock is locked. The preset difference is taken from [0.2A, 1A].

[0112] In other words, the controller determines to lock the differential lock when it determines that the wheel speed difference between the left and right drive wheels is less than or equal to the second difference threshold, and / or the first actual current of the differential lock is greater than the first preset current value.

[0113] If the controller determines that the differential lock is locked, it will set the differential lock's status to locked. For example, the controller writes a lock status indicator to the status register, such as 1 for locked, 0 for unlocked, and 2 for fault. Next, the controller outputs a fourth message indicating that the differential lock is locked. The controller can output this fourth message using at least one of the following methods: voice, text, light, or sound effects. For example, the controller might display the text message "Differential lock locked" on the instrument panel. If the controller determines that the differential lock is not locked, it will set the differential lock's status to unlocked. For example, the controller will not modify the status indicator in the status register, keeping the status indicator in the status register at 0. Simultaneously, the controller will output a fifth message indicating that the differential lock is not locked. The controller can output this fifth message using at least one of the following methods: voice, text, light, or sound effects. For example, the controller might display the text message "Differential lock locking failed" on the instrument panel.

[0114] This application's embodiments, by setting locking conditions, can more comprehensively assess whether the differential lock is locked, thereby improving the accuracy of the judgment and further ensuring that the differential lock still has good performance and safety reliability under complex operating conditions. In the prior art, vehicle differential locks typically include a dedicated sensor for acquiring coupling data of the driving gear and the engagement gear, and determine whether the differential lock is locked based on the data acquired by the dedicated sensor. This dedicated sensor can be, for example, a sensor for acquiring the travel of the driving gear, and the coupling data can be, for example, the travel data of the driving gear. This method has high hardware costs. This application determines whether the differential lock is locked based on the wheel speed difference between the left and right drive wheels and / or the actual current of the differential lock. It does not rely on the above-mentioned dedicated sensor, which can effectively reduce hardware costs.

[0115] In summary, during actual implementation, after the controller activates the differential lock based on the first drive current value, it enters a process to determine the locking status. Through comprehensive analysis of multi-dimensional data, it determines whether the differential lock has truly engaged. If engaged, a locking notification is output, clearly informing the driver of the vehicle's current status. If locking fails, an unlocked notification is output, reminding the driver to adjust their operation or improve the environment before attempting again. This two-way feedback mechanism not only improves the accuracy and timeliness of the response but also enhances the user-friendliness and practicality of the human-machine interaction, thereby comprehensively improving the vehicle's ability to navigate complex road conditions and its operational safety.

[0116] In some embodiments, after the differential lock engages, the controller further controls the differential lock to unlock or reduces the drive current value to reduce power consumption based on the vehicle's subsequent driving parameters, i.e., the third driving parameters. The third driving parameters are acquired later than the second driving parameters.

[0117] For example, the controller acquires a third driving parameter of the vehicle based on multiple sensors deployed in the vehicle. This third driving parameter is at least one of the following: the wheel speed of the vehicle's left drive wheel, the wheel speed of the vehicle's right drive wheel, the vehicle's overall speed, and the vehicle's steering angle. The controller can detect whether the third driving parameter satisfies a third condition. This third condition is related to at least one of the vehicle's overall speed, the vehicle's steering angle, and the difference in wheel speeds between the vehicle's left and right wheels.

[0118] The third condition could be, for example, that the difference in wheel speed between the left and right drive wheels of the vehicle is greater than a third difference threshold and lasts for a preset duration; the vehicle speed is greater than a second speed threshold; the vehicle's steering angle is greater than a second angle threshold and lasts for a preset duration; or the vehicle speed is greater than a third speed threshold and the vehicle's steering angle is greater than a third angle threshold. Specifically, the third difference threshold is taken from [3km / h, 5km / h], the second speed threshold is taken from [40km / h, 50km / h], the second angle threshold is taken from [90°, 120°], the third speed threshold is taken from [20km / h, 25km / h], the third angle threshold is taken from [50°, 70°], and the preset duration is taken from [200ms, 500ms].

[0119] In response to the detection that a third driving parameter meets a third condition, the controller unlocks the differential lock. This third condition can be understood as the automatic unlocking condition of the differential lock. When the vehicle's driving parameters meet the third condition, automatic unlocking is triggered, meaning the controller unlocks the differential lock.

[0120] If the third condition is not met, the controller can detect whether the third driving parameter meets the fourth condition. Meeting the fourth condition indicates that the vehicle is in a stable driving state. The fourth condition is related to at least one of the vehicle speed, the wheel speed difference between the left and right wheels, and the wheel steering angle. For example, the fourth condition could be that the vehicle speed is greater than a third speed threshold for a preset duration greater than 1 second or 2 seconds, and the wheel speed difference between the left and right drive wheels is greater than a fourth difference threshold for a preset duration greater than 1 second or 2 seconds. Meeting this fourth condition indicates that the vehicle begins normal driving and the speed difference remains constant. The third speed threshold is, for example, taken from [5 km / h, 15 km / h], and the fourth difference threshold is taken from [3 km / h, 5 km / h].

[0121] Alternatively, the fourth condition could be that the vehicle speed is greater than a third speed threshold, the vehicle's steering angle is greater than a third angle threshold, and the difference in wheel speeds between the left and right drive wheels is greater than a fourth difference threshold. Meeting this fourth condition indicates that there is no speed difference when the vehicle is turning. The third angle threshold takes values ​​in the range [50°, 70°].

[0122] If the third driving parameter satisfies the fourth condition, the differential lock has a self-locking capability after normal coupling, which can reduce the drive current and power consumption. For example, the controller switches the differential lock's drive current to a second drive current. Specifically, the controller switches the excitation coil's drive current to the second drive current, maintaining the differential lock's locked state based on the second drive current. The second drive current is less than the first drive current, used to maintain the differential lock's closed state, while reducing energy consumption and lowering the risk of coil overheating.

[0123] In some embodiments, the second drive current = the first drive current - a preset value. The preset value may be, for example, 1A or 2A.

[0124] In other embodiments, the second drive current is determined based on the current return spring force. For example, a one-to-one mapping relationship between multiple return spring forces and multiple drive currents is pre-defined. A drive current corresponding to each return spring force refers to the minimum drive current required to maintain differential lock engagement (i.e., the primary gear and drive gear are fully engaged) under that return spring force. The controller can obtain the current return spring force using a pressure sensor installed on the spring. Alternatively, the controller can obtain the spring's compression displacement in real time using a displacement sensor installed on the spring, and directly calculate the current return spring force by combining this with the spring's preset elastic coefficient. Then, the controller can determine the second drive current matching the current return spring force based on the current return spring force and the mapping relationship described above.

[0125] In this embodiment, the differential lock is unlocked promptly when the automatic unlocking conditions are met, and switches to a low-power maintenance mode after the differential lock is successfully locked. When it is detected that the differential lock is forcibly maintained under inappropriate conditions, timely unlocking can be implemented to protect the differential structure from damage. Simultaneously, when the differential lock is detected to be in a stable locked state, a smaller drive current is used to maintain the locked state, which improves energy efficiency.

[0126] In the embodiments described above, the controller can automatically trigger differential lock unlocking when certain conditions are met. In other embodiments, the controller can also receive a second command from the driver to unlock the differential lock and control the differential lock unlocking accordingly. For example, the driver can issue the second command via at least one of several methods, such as a physical button, a virtual button on the vehicle's display screen, or a vehicle microphone. Taking a physical button as an example, the vehicle's central control area can be configured to respond to the driver's triggering operation on the physical button, thereby controlling the differential lock unlocking.

[0127] In some embodiments, the controller controls the differential lock to unlock by reducing the drive current of the vehicle differential. For example, the controller sets the drive current of the differential lock to a preset value, such as 0A. After setting the drive current of the differential lock to the preset value, the controller's high-current drive port stops outputting current, the excitation coil is de-energized and the electromagnetic force dissipates, the differential lock locking mechanism disengages, the differential lock is released from its locked state and resumes normal differential function, allowing the left and right drive wheels to operate independently at differential speeds. The actual current of the differential lock gradually decreases to 0A at a preset rate.

[0128] After unlocking the differential lock, the controller further determines whether the differential lock has successfully entered the unlocked state. For example, the controller can acquire the second actual current of the differential lock. The second actual current reflects the operating status of the differential lock and whether the expected unlocking action has been completed. For example, when the second actual current is stable at a low level, it indicates that the electromagnet has been de-energized and the differential lock is in the unlocked state; while if the second actual current is consistently higher than the normal range, it may indicate that the differential lock has not fully unlocked or that other abnormalities exist. By collecting and analyzing the second actual current of the differential lock, it is possible to determine whether the operating status of the differential lock meets expectations, providing data support for subsequent unlocking decisions.

[0129] For example, if the second actual current of the differential lock meets the second preset condition, the controller determines that the differential lock has successfully entered the unlocked state. If the second actual current of the differential lock does not meet the second preset condition, the controller determines that the differential lock has not successfully entered the unlocked state. The second preset condition could be, for example, that the actual current of the differential lock is less than a preset value and the duration exceeds a preset duration, such as 1 second or 2 seconds.

[0130] If the controller determines that the differential lock has successfully entered the unlocked state, it can switch the differential lock's state to the unlocked state. The controller can also output a sixth notification message indicating that the differential lock has unlocked and / or the reason for the unlocking. This sixth notification message is a driver interaction feedback mechanism used to clearly inform the driver of the differential lock's status change and its cause. The sixth notification message can take various forms, including text prompts, instrument panel indicator lights, and voice reminders. For example, when the differential lock successfully enters the unlocked state, the instrument panel will display "Differential Lock Released," accompanied by a green indicator light illuminating, indicating that the vehicle control system has returned to normal operating mode.

[0131] For example, if the wheel speed difference between the left and right drive wheels exceeds 2 km / h and continues for a preset duration, the controller will unlock the differential lock. Upon successfully entering the unlocked state, the instrument panel will display a message: "Locking failed, please try locking the differential lock again later." This strategy monitors whether the differential lock is working properly and compensates for situations where the travel distance is not directly monitored.

[0132] For example, when the vehicle speed exceeds 40 km / h, it is determined to be speeding and the differential lock will be unlocked. After successfully entering the unlocked state, the instrument panel will display a message: "Speeding unlocked, please reduce speed and use the differential lock." This strategy is to prevent safety hazards caused by the lack of differential lock between the left and right wheels at high vehicle speeds.

[0133] When the vehicle's steering angle is greater than 90° and continues for a preset duration, or when the vehicle speed is greater than 20km / h and the steering angle is greater than 50°, the controller unlocks the differential lock. After successfully entering the unlock state, the instrument panel will display a message: "Unlock due to excessive steering. Please use the differential lock again later." This strategy prevents the vehicle from overturning due to the lack of differential speed between the left and right wheels while driving.

[0134] If the controller determines that the differential lock has not successfully entered the unlock state, the controller determines that the differential lock is faulty. The controller can set the differential lock status to faulty and output a seventh prompt message to indicate the differential lock fault.

[0135] A fault state refers to an abnormal operating state that the differential lock system enters after detecting an anomaly. This indicates that the differential lock system may have a hardware or software problem and cannot continue to perform its control functions normally. The seventh warning message can be displayed on the instrument panel in the form of text, icons, or voice prompts. Specific examples include "Differential lock fault, please check the system," and "Differential lock cannot lock, please try again later." The seventh warning message not only enhances the driver's awareness of the system status but also effectively guides the driver to take the correct actions, such as slowing down to a stop or switching to a safe mode.

[0136] This embodiment collects the second actual current of the differential lock and determines the unlocking status based on this second actual current. Simultaneously, it outputs a prompt message based on the judgment structure. This improves the intelligence level of differential lock control, enhances stability, and thus improves the vehicle's ability to get out of trouble and its driving safety in complex road conditions.

[0137] In some embodiments, after setting the differential lock to the unlocked state, the controller can continue to acquire a fourth driving parameter of the vehicle to determine whether the differential lock has truly been successfully unlocked. The acquisition time of the fourth driving parameter is later than the acquisition time of the third driving parameter.

[0138] For example, the controller acquires a fourth driving parameter of the vehicle. This fourth driving parameter is at least one of the following: the wheel speed of the vehicle's left drive wheel, the wheel speed of the vehicle's right drive wheel, the vehicle's overall speed, and the vehicle's steering angle. The controller can detect whether the fourth driving parameter satisfies a fifth condition. This fifth condition is related to the vehicle's overall speed, the vehicle's steering angle, and the difference in wheel speeds between the vehicle's left and right wheels.

[0139] The fifth condition could be, for example, that the vehicle speed is greater than the fourth speed threshold, the vehicle steering angle is greater than the fourth angle threshold (e.g., 90°), or the difference in wheel speed between the left and right drive wheels is greater than the fifth difference threshold. The fourth speed threshold is taken from [5 km / h, 15 km / h], the fourth angle threshold from [90°, 120°], and the fifth difference threshold from [3 km / h, 5 km / h].

[0140] Alternatively, the fifth condition could be that the speed difference between the left and right drive wheels of the vehicle is greater than the fifth difference threshold and lasts for a preset duration, such as 2 seconds.

[0141] If the fourth driving parameter meets the fifth condition, it indicates that the differential lock has been successfully unlocked. If the fourth driving parameter does not meet the fifth condition, it indicates that the differential lock has not been successfully unlocked. In the case of successful unlocking, the controller can disconnect the power supply circuit to the differential lock; for example, the controller can control a relay to disconnect the power supply circuit to the differential lock. In the case of unsuccessful unlocking, the differential lock is set to a fault state. Setting it to a fault state prevents the differential lock from being forcibly locked in the event of a malfunction, thereby avoiding potential mechanical shocks or further damage to the differential lock components. The fault state setting enhances the system's fault tolerance and stability under complex operating conditions, ensuring vehicle safety. The fault state can also be referred to as the locked-down state. The sixth prompt message is as described above and will not be repeated here.

[0142] By dynamically controlling the power supply circuit of the differential lock to disconnect or output fault information through the fourth driving parameter, the power supply circuit can be disconnected in time after the differential lock is successfully unlocked, reducing power consumption and preventing the differential lock from working under fault conditions. This can reduce hardware wear and safety hazards, and thus improve the overall performance and reliability of the relays in the differential lock.

[0143] The following describes a differential lock control method, control device, vehicle, and computer-readable storage medium provided in the embodiments of this application, in conjunction with specific application scenarios.

[0144] During driving, due to uneven road surfaces and turning, the left and right tires need to move at different speeds. Otherwise, problems such as abnormal tire wear and lateral wheel drift may occur. The differential device is an important device to achieve different speeds for the left and right wheels with the same power source. The most common differential device is the planetary gear structure. Its function is to use the rotation of the planetary gears to transmit the same differential speed to the drive shaft through the half-shaft gears, thereby achieving differential speed and meeting the needs of turning and driving on uneven road surfaces.

[0145] However, in some special scenarios, such as when one wheel has near zero traction while the other has greater traction during off-road driving, the differential function will cause all the power to be transferred to the side with lower traction. The side with greater traction will not receive power, causing the vehicle to slip and become unable to move forward. Maintaining a slipping state for a long time can also cause problems such as burn-out and damage to the differential device.

[0146] To overcome the slippage and spinning problem in this scenario, a locking function is usually added to the differential to disable the differential, forcing the left and right ends to rotate in unison, thus solving the slippage problem and improving the vehicle's passability. This is usually achieved by connecting the half-shaft gear to the differential housing, so that the differential no longer functions and the left and right drive wheels receive the same torque.

[0147] Differential locks can only be engaged in special scenarios, such as getting out of trouble or climbing. If they remain engaged at high speeds, they will cause abnormal wear and, in severe cases, safety issues such as rollover. Therefore, they require high control.

[0148] Related Technology 1 mentions a motor-driven differential lock control method. This method is relatively simple, only considering the execution of locking without considering whether locking is suitable for actual driving. It also raises concerns about what to do if the driver forgets to disengage the lock, posing a significant safety hazard.

[0149] The electromagnetic differential lock control method proposed in related technology 2 takes vehicle speed into account when opening and closing, and focuses on how to determine vehicle speed. However, it does not take into account information such as steering, throttle opening, and speed difference. Similarly, it does not have sufficient safety considerations. If the differential lock is closed during a sharp turn under certain conditions, it will affect the vehicle's driving and may even cause it to roll over.

[0150] The electromagnetic differential lock control method proposed in related technology 3 takes into account steering, vehicle speed, and status switch, and provides fault diagnosis prompts. However, it does not consider that if the vehicle speed is 0, the throttle is on, the wheels are slipping in place, and there is a speed difference between the left and right wheels, the intervention of the lock after triggering the engagement switch will cause internal shock to the differential, resulting in hardware damage. At the same time, this method requires the differential lock status switch as an important closed-loop control signal, making the hardware more complex.

[0151] Furthermore, regardless of whether the aforementioned technologies employ motor control or solenoid valve control, none of them consider the impact of oil temperature on the performance of the motor or solenoid valve. The applicant has discovered that temperature affects the electromagnetic coil as follows: 1. Coil resistance variation: The copper wire resistance of the electromagnetic coil has a positive temperature coefficient (approximately 0.4% / ℃). Increased temperature leads to increased resistance, which, under constant voltage, reduces the current and thus decreases the electromagnetic attraction. This may prevent the differential lock from fully engaging when needed, posing a safety hazard.

[0152] 2. Changes in the magnetic properties of the core material: The permeability of commonly used soft magnetic materials (such as silicon steel and electrical pure iron) changes with temperature. Increased temperature may lead to a decrease in saturation magnetic induction, which also affects the final output torque.

[0153] Meanwhile, the above-mentioned technologies do not take into account the influence of throttle opening. There is a delay between the controller's judgment that the condition is met and the actuator's execution of the action. If the throttle is pressed during the delay, the instantaneous speed change will conflict with the coupled action of the actuator, resulting in gear grinding and abnormal wear.

[0154] To address this, the present invention provides a differential lock control method. Through software optimization, the differential lock status switch is eliminated. By calculating and analyzing signals such as vehicle speed, gradient, oil temperature, steering, throttle opening, and wheel speed, closed-loop vehicle control is achieved. This optimizes the gear grinding problem caused by speed difference during differential coupling, proposes compensation strategies for changes in gradient and temperature, provides automatic lock reminders to help drivers use the differential lock more reasonably and safely, and proposes a fault diagnosis method to improve system safety redundancy.

[0155] In some embodiments, the differential lock of the present invention uses an electromagnet as the actuator. Its working principle is as follows: when the electromagnet is energized, it pushes the drive gear and engagement gear to couple, thereby locking the left and right wheels. After de-energization, the differential lock returns to its original position via a spring, thus disengaging. To achieve closed-loop control, the differential lock controller needs to collect signals including: differential lock control switch, vehicle speed, vehicle speed signal validity, left wheel speed, left wheel speed validity, right wheel speed, right wheel speed validity, steering angle, transmission oil temperature, and throttle opening.

[0156] In some embodiments, the main process of the control strategy is as follows: Locking Control Process: When the differential lock controller receives the locking command from the differential lock control switch, it judges the vehicle speed, the wheel speed difference between the left and right drive wheels, the steering angle, and the throttle opening. If the set conditions are met, it controls the electromagnet drive current according to temperature compensation. If the current continues for a certain period of time, the locking is considered successful, and the instrument indicator light is illuminated via a relay to remind the user that the differential lock has started working. If the actual current and wheel speed difference do not meet the conditions, the locking start failure is reported. After the vehicle starts moving, if the steering wheel angle and the wheel speed difference between the left and right drive wheels meet the threshold, the differential lock is considered successfully locked. The instrument indicator light is maintained, and the current is reduced in conjunction with transmission temperature compensation to reduce power consumption.

[0157] Meanwhile, when the wheel speed difference between the left and right drive wheels exceeds a certain threshold and the vehicle speed is below the threshold for a certain period of time, the differential lock controller sends a reminder to the instrument panel, prompting the driver to try locking the differential lock to help the vehicle drive normally.

[0158] Unlocking control process: If actively disengaged, when the differential lock controller receives the disengagement command from the push-button switch, the controller controls the electromagnet drive current to 0A. If the actual current remains below the target value for a certain period of time, the initial judgment is that the lock has been successfully disengaged. If the detected vehicle speed is greater than the threshold, or the vehicle speed and steering speed are both greater than the threshold, the controller will automatically control the electromagnet drive current to 0A. If the actual current remains below the target value for a certain period of time, the judgment is that the lock has been successfully disengaged, and the driver will be notified via the instrument panel that the differential lock has been disengaged.

[0159] Fault Detection Procedure: Perform the fault detection procedure before using the differential lock. ① Switch Sticking Fault: When the switch button is identified as stuck, the differential lock controller reports a fault and controls the electromagnet drive current to 0A, illuminating the instrument fault light. ② Locking Fault: If the vehicle speed, steering wheel angle, or wheel speed difference does not meet the threshold and duration requirements, or if the vehicle speed validity, left wheel speed validity, or right wheel speed validity is invalid, or if the stable current of the electromagnet drive is lower than the threshold after locking, locking failure is reported, prompting a retry later. ③ Disconnection Fault: When the electromagnet drive current is 0A, and the steering wheel angle, vehicle speed, and left / right wheel speed difference meet the threshold criteria, the controller reports a fault, the fault light illuminates, and the vehicle speed is limited. ④ Electrical Fault: This includes short circuits in the relay control terminal and power control terminal, excessive current, etc. If the conditions are met, the controller reports a fault, and the fault light illuminates.

[0160] Compared with existing technologies, this application has the following advantages: It provides an automatic locking reminder to help drivers use the differential lock function more effectively. The locking entry conditions include throttle opening and gradient, enabling more accurate determination of whether it is suitable to enter the differential lock state and avoiding coupling gear damage. Temperature compensation is considered to prevent insufficient current from affecting locking success in extreme weather conditions. The differential lock status switch is eliminated, and multiple signal thresholds are used for locking and unlocking determination, saving hardware costs. Specific fault diagnosis logic is developed based on the system to improve safety redundancy.

[0161] The following is combined Figure 4 This application introduces a differential lock control method provided by an embodiment, such as... Figure 4 As shown, the method includes: S1, in response to detecting that the vehicle is in a slippery state, outputs the first prompt message.

[0162] For example, if a vehicle's driving parameters meet at least one of the following conditions: vehicle speed < 2 km / h for a duration of ≥ 2 s, wheel speed difference between the left and right drive wheels ≥ 10 km / h for a duration of ≥ 2 s, or accelerator pedal opening ≥ 30% for a duration of ≥ 2 s, the vehicle is determined to be in a slippery state.

[0163] S2 receives the driver's operation on the target switch and generates the first instruction.

[0164] When the target switch is triggered, the controller first performs power-on and fault detection, see details. Figure 5 The method shown will not be elaborated upon; the first instruction is generated after the test is passed.

[0165] S3, determine whether the differential lock is locked.

[0166] S4, if the differential lock is in the locked state, output the second prompt message.

[0167] The second prompt message is such as "The differential lock is in the locked state".

[0168] S5. If the differential lock is in the unlocked state, determine whether the first condition is met.

[0169] The differential lock controller determines whether the differential lock is locked. If it is locked, the instrument panel will indicate that the differential lock is locked. If it is unlocked, the relay will be closed to determine the locking conditions. Locking conditions include at least one of the following: accelerator pedal opening ≤ opening XX, vehicle speed ≤ 5 km / h, wheel speed difference between the left and right drive wheels ≤ 5 km / h, and steering wheel angle ≤ 90°. The accelerator pedal opening ≤ opening XX condition is used to prevent damage during differential lock coupling. Excessive accelerator pedal opening generates significant acceleration, which can cause a large speed difference if the differential lock is not fully coupled, leading to impact and gear breakage. Additionally, considering that slopes reduce acceleration, a slope compensation is applied: opening XX = 30% + slope value * M, where M is the compensation coefficient, for example, 1.2. The slope refers to the gradient of the road surface the vehicle is currently on. Excessive vehicle speed or wheel speed difference can also cause differential lock coupling damage. If the steering wheel is not straightened, coupled driving poses a risk of rollover. Therefore, it is also necessary to make a judgment based on vehicle speed, wheel speed difference, and steering wheel direction.

[0170] If the first condition is not met, execute S6; if the first condition is met, execute S7.

[0171] S6. If the first condition is not met, output the third prompt message.

[0172] If the conditions are not met, the control instrument will indicate that the differential lock's operating conditions are not met. Please decelerate and stop the vehicle, straighten the steering wheel, and then lock the differential lock. At the same time, the differential lock indicator light will turn off, the relay will be disconnected, and the control process will exit.

[0173] S7. If the first condition is met, obtain the actual temperature of the excitation coil and the target locking torque of the differential lock, and determine the first driving current based on the actual temperature of the excitation coil and the target locking torque of the differential lock.

[0174] If the first condition is met, the electromagnet will be driven by the first driving current. This first driving current needs to be optimized according to the temperature compensation strategy. See the previous description for details, which will not be repeated here.

[0175] After the current is emitted, the locking status will be judged. Since the locking status switch has been cancelled, it is not possible to directly judge whether the coupling is completed by the movement stroke of the moving gear. Considering that the differential lock is only activated under special working conditions (climbing, off-roading, getting out of trouble, etc.), its usage scenario must start from when the vehicle is stationary or at a low speed. If the coupling is not normal, a wheel speed difference will definitely be generated. By collecting the wheel speeds of the left and right wheels and judging the speed difference, it can be determined whether the coupling is normal. Therefore, this method can also include S8.

[0176] S8, obtain the vehicle's second driving parameters and / or the first actual current of the differential lock.

[0177] S9 determines whether the locking conditions are met based on the second driving parameters and / or the first actual current of the differential lock.

[0178] The locking conditions are: the first actual current > the first drive circuit -1A and the duration > 1s, and / or the wheel speed difference between the left and right drive wheels ≤ 1km / h. Here, 1A is a recommended value. Theoretically, after coupling, the wheel speed difference between the left and right wheels is 0, and 1km / h is for speed sensor error correction.

[0179] S10, if the locking condition is met, set the differential lock to the locked state and output a fourth prompt message indicating that the differential lock is locked.

[0180] S11, if the locking condition is not met, control the differential lock to the unlocked state and output the fifth prompt message indicating that the differential lock is not locked.

[0181] Once the conditions are met, the instrument panel indicates that the differential lock is locked, and the controller sets the differential lock to the locked state. However, it is still necessary to continuously monitor the vehicle speed, the wheel speed difference between the left and right drive wheels, and the steering angle.

[0182] S12, determine whether the third driving parameter meets the third or fourth condition.

[0183] S13, if the third driving parameter meets the third condition, trigger automatic unlocking.

[0184] If the wheel speed difference between the left and right drive wheels exceeds 2 km / h and lasts for more than 200 ms, locking is deemed a failure, and unlocking control is initiated. The instrument panel displays the message: "Locking failed, please try locking the differential lock again later." This strategy monitors whether the differential lock is functioning correctly and compensates for situations where the travel distance is not directly monitored.

[0185] When the vehicle speed exceeds 40 km / h, it is determined to be speeding and the differential lock will be activated, triggering the unlock control and displaying a message on the instrument panel: "Speeding unlock, please reduce speed and use the differential lock." This strategy is designed to prevent safety hazards caused by the lack of differential lock between the left and right wheels at high speeds.

[0186] When the steering angle is greater than 90° and the duration is greater than 200ms, or when the vehicle speed is greater than 20km / h and the steering angle is greater than 50°, the unlock control will be activated and the instrument panel will display a message: "Unlock due to excessive steering. Please use the differential lock again later." This strategy prevents the vehicle from overturning due to the lack of differential speed between the left and right wheels while driving.

[0187] S14, if the third driving parameter satisfies the fourth condition, the differential lock is maintained in a locked state based on the second driving current.

[0188] The second drive current is less than the first drive current.

[0189] The fourth condition can be at least one of the following: vehicle speed > 10 km / h and duration > 2 seconds, or the speed difference between the left and right wheels < 2 km / h and duration > 2 seconds. Alternatively, the fourth condition can be at least one of the following: vehicle speed > 10 km / h, steering wheel turn > 50°, or the speed difference between the left and right drive wheels < 2 km / h.

[0190] It should be understood that in this embodiment, if the third driving parameter does not meet the third condition but meets the fourth condition, the differential lock is maintained in a locked state according to the second drive current. If the third driving parameter does not meet the third condition and does not meet the fourth condition, the differential lock is maintained in a locked state according to the first drive current.

[0191] S15, in response to active or automatic triggering of unlocking, sets the drive current of the differential lock to 0A.

[0192] S16, determine whether the second actual current meets the second preset condition.

[0193] S17, the second actual current meets the second preset condition, the differential lock is set to the unlocked state, and the sixth prompt message is output.

[0194] When the user actively presses the button to unlock or triggers automatic unlocking, the control current is initially set to 0A. If the actual current is less than 0.2A and the duration exceeds 1 second, the unlocking is determined to be complete and an instrument prompt is given. The controller then sets the differential to the unlocked state.

[0195] If the user actively triggers unlocking, the instrument panel will display "Unlocked". If automatic unlocking is caused by excessive steering, the instrument panel will display "Excessive Steering Unlocked, please try using the differential lock again later". If unlocking is caused by speeding, the instrument panel will display "Speeding Unlocked, please reduce speed and use the differential lock". If automatic unlocking is caused by not meeting the locking conditions, the instrument panel will display "Locking Failed, please try locking the differential lock again later". After the instrument panel displays the corresponding information, the control indicator light will turn off.

[0196] S18, if the second actual current does not meet the second preset condition, the differential lock is set to a fault state, and a seventh prompt message indicating a differential lock fault is output.

[0197] S19, determine whether the fourth driving parameter meets the fifth condition.

[0198] To ensure that unlocking has been completed, the controller will continue to make supplementary judgments. The fifth condition includes at least one of the following: vehicle speed > 10 km / h, steering angle > 90°, and wheel speed difference between the left and right drive wheels > 2 km / h. Alternatively, the fifth condition includes: wheel speed difference between the left and right drive wheels > 2 km / h and duration > 2 seconds.

[0199] S20, if the fourth driving parameter meets the fifth condition, the power supply circuit for controlling the differential lock is disconnected.

[0200] If the fourth driving parameter meets the fifth condition, the power supply circuit for the differential lock is disconnected and the indicator light flashes for 5 seconds to indicate that unlocking is complete. If the fourth driving parameter does not meet the fifth condition, the differential lock is set to a fault state, and a sixth prompt message indicating a differential lock malfunction is output. For example, if the fourth driving parameter meets at least one of the following: vehicle speed > 10 km / h, steering angle > 90°, and wheel speed difference between the left and right drive wheels < 2 km / h, the differential lock is set to a fault state, and a sixth prompt message indicating a differential lock malfunction is output.

[0201] In some embodiments, a fault check is performed before using the differential lock. The fault check process is as follows: Figure 5 As shown.

[0202] S501 checks whether the vehicle is powered on.

[0203] If the vehicle is not powered on, the process ends. If the vehicle is powered on, proceed to step S502.

[0204] S502, sequentially check whether the differential lock has switch sticking fault, single-sided fault, double-sided fault, disconnection fault, other double-sided fault and communication fault.

[0205] For example, check whether the differential lock switch is stuck and causing the signal to be generated. Refer to the relevant conditions for determining the condition of a conventional electrical button reset switch.

[0206] For example, whether a single-sided fault occurs, including a short circuit to the power supply, a short circuit to ground, or an open circuit fault at the relay control terminal; a short circuit to the power supply, a short circuit to ground, or an open circuit fault at the current control terminal; and a current ≥3A after 5 seconds of unlocking the control.

[0207] S503 If the differential lock experiences switch sticking or unilateral fault, set the differential lock to a fault state.

[0208] S504 triggers the unlock control and disables the differential lock.

[0209] S505 determines the current state of the differential lock.

[0210] S506 If the differential lock is locked at this time, the yellow light will flash for 5 seconds and then display a fault icon, indicating a differential lock fault on the instrument panel.

[0211] S507: If the differential lock is currently unlocked, the malfunction indicator lamp will illuminate and display a malfunction icon.

[0212] In both scenarios described above, a fault is suspected in the switch or power system. The controller sets the differential lock to a fault state, triggers unlocking control, and disables locking the differential lock. Simultaneously, it checks the current state of the differential lock. If the differential lock is locked, a flashing indicator light will illuminate for 5 seconds, the instrument panel will display a fault light, and the message "Differential lock system fault, function deactivated" will be displayed. If the differential lock is unlocked, the fault light will illuminate directly.

[0213] S508: If the differential lock experiences a double-sided fault, disconnection fault, other double-sided faults, or communication fault, the differential lock will be set to a fault state.

[0214] Double-sided faults include a short circuit between the current control terminal and the power supply, and a short circuit between the relay control terminal and ground. Other double-sided faults include: other double-sided faults that are not double-sided short circuit faults, such as a low-side short circuit / open circuit fault to the power supply and a high-side short circuit to the power supply, a low-side short circuit / open circuit fault to ground and a high-side short circuit to ground, or a low-side short circuit / open circuit fault to ground / power supply and a high-side open circuit fault. Communication faults include: failure to report vehicle speed signal validity, left wheel speed validity, or right wheel speed validity signals, or loss of any signal for more than 1 second.

[0215] S509, the current control terminal and the relay control terminal are simultaneously disconnected and the locking action is prohibited.

[0216] S510, the differential lock control fault icon is lit.

[0217] S511, the control instrument indicates a fault.

[0218] The S512's powertrain limits the vehicle speed to 30 km / h.

[0219] S513 If the user triggers the lock, the control instrument will remind that the lock is not allowed.

[0220] The controller sets the differential lock control status to fault state, and the current control terminal and relay control terminal are simultaneously disconnected and the locking action is prohibited. The differential lock fault light on the instrument panel is illuminated, and the instrument panel prompts: Differential lock system fault. Please slow down immediately and pull over to the side of the road. The power system limits the vehicle speed to 30 km / h. At this time, if the user operates the button, the instrument panel will prompt that the differential lock system is faulty and cannot be locked.

[0221] The preceding text, with reference to specific embodiments, introduced a differential lock control method provided by the present application. The following text, with reference to specific embodiments and accompanying drawings, introduces the related devices provided by the present application.

[0222] Figure 6 This is a schematic diagram of the structure of a differential lock control device provided in an embodiment of this application, as shown below. Figure 6 As shown, the control device 600 includes: a first acquisition unit 610, a second acquisition unit 620, a determination unit 630, and a control unit. The control device 600 is applied to a vehicle including a differential lock, the differential lock including an excitation coil for converting electrical energy into electromagnetic force to control the differential lock locking. The first acquisition unit 610 is used to acquire the actual temperature of the excitation coil in response to the first command to activate the differential lock.

[0223] The second acquisition unit 620 is used to acquire the target locking torque of the differential lock; the target locking torque is matched with the current driving conditions of the vehicle.

[0224] The determining unit 630 is used to determine the first drive current required for the differential lock to generate the target locking torque at the actual temperature, based on the actual temperature and the target locking torque.

[0225] Control unit 640 is used to control differential lock locking based on first drive current.

[0226] The first acquisition unit 610 is also used to acquire the actual resistance value of a temperature-sensitive resistor installed in the differential lock near the excitation coil, and determine the actual temperature of the excitation coil based on the actual resistance value and the temperature change characteristics of the temperature-sensitive resistor; or, acquire the oil temperature of the oil in the vehicle's differential, and determine the actual temperature of the excitation coil based on the oil temperature; the temperature of the excitation coil is positively correlated with the oil temperature; the differential lock is located in the differential.

[0227] The determining unit 630 is also used to determine the first driving current based on the actual temperature, the target locking torque and the first mapping relationship; wherein, the first mapping relationship characterizes the correspondence between the temperature of the excitation coil, the locking torque of the differential lock and the driving current.

[0228] The determining unit 630 is also used to determine, based on the target locking torque, the reference drive current required for the differential lock to generate the target locking torque at the reference temperature; to determine the magnetic performance attenuation coefficient based on the actual temperature of the excitation coil; to determine the actual resistance of the excitation coil at the actual temperature based on the actual temperature of the excitation coil; and to determine the first drive current based on the magnetic performance attenuation coefficient, the actual resistance, and the reference drive current.

[0229] The control unit 640 is also configured to, in response to detecting that the vehicle is in a slipping state, output a first prompt message instructing the driver to operate a target switch to activate the differential lock; receive the driver's operation on the target switch; and generate a first command.

[0230] The control unit 640 is also used to control the power supply circuit of the differential lock to be turned on and to obtain the actual temperature of the excitation coil if the differential lock is in the unlocked state; and to output a second prompt message indicating that the differential lock has been activated if the differential lock is in the locked state.

[0231] The control unit 640 is also used to acquire first driving parameters of the vehicle; if the differential lock is in the unlocked state and the first driving parameters meet the first condition, it acquires the actual temperature of the excitation coil; the method further includes: if the differential lock is in the unlocked state and the first driving parameters do not meet the first condition, it outputs a third prompt message indicating that the differential lock cannot be activated.

[0232] The control unit 640 is further configured to acquire a second driving parameter of the vehicle and / or a first actual current of the differential lock; based on the second driving parameter and / or the first actual current of the differential lock, determine whether the locking condition is met; if the locking condition is met, set the state of the differential lock to the locked state and output a fourth prompt message indicating that the differential lock is locked; if the locking condition is not met, control the state of the differential lock to the unlocked state and output a fifth prompt message indicating that the differential lock is not locked.

[0233] The control unit 640 is also used to acquire a third driving parameter of the vehicle; if the third driving parameter meets a third condition, control the differential lock to unlock; if the third driving parameter meets a fourth condition, maintain the differential lock in a locked state based on a second drive current; the second drive current is less than the first drive current.

[0234] The control unit 640 is also configured to control the differential lock to unlock in response to a second command to release the differential lock.

[0235] The control unit 640 is also configured to set the differential lock drive current to a preset value; acquire the second actual current of the differential lock; if the second actual current meets the second preset condition, set the state of the differential lock to the unlocked state and output a sixth prompt message; wherein the sixth prompt message indicates that the differential lock has been unlocked and / or the reason for the differential lock being unlocked; if the second actual current does not meet the second preset condition, set the state of the differential lock to the fault state and output a seventh prompt message indicating a differential lock fault.

[0236] The control unit 640 is also used to acquire the fourth driving parameter of the vehicle; if the fourth driving parameter meets the fifth condition, the power supply circuit of the differential lock is disconnected; if the fourth driving parameter does not meet the fifth condition, the state of the differential lock is set to a fault state, and a seventh prompt message indicating the differential lock fault is output.

[0237] Figure 7 This is a schematic diagram of a vehicle structure provided in an embodiment of this application. The vehicle 700 includes a differential lock 710 and a control device 720. Figure 8 As shown, the control device 720 includes one or more processors 721 and one or more memories 722. The control device 720 may be, for example, the controller described above.

[0238] The processor 721 can support the control device in implementing the methods described in the preceding method embodiments.

[0239] The memory 722 stores a program that can be executed by the processor 721, causing the processor 721 to perform the methods described in the preceding method embodiments. The memory 722 can be independent of the processor 721 or integrated into the processor 721.

[0240] Optionally, the control device 720 may also include a transceiver 723. The processor 721 can communicate with other devices or chips via the transceiver 723. For example, the processor 721 can send and receive data with other devices or chips via the transceiver 723.

[0241] This application provides a computer-readable storage medium storing one or more programs that can be executed by one or more processors to implement the steps of the methods described in any of the above embodiments.

[0242] It should be noted that the descriptions of the computer-readable storage medium and device embodiments above are similar to the descriptions of the method embodiments above, and have similar beneficial effects. For technical details not disclosed in the computer-readable storage medium and device embodiments of this application, please refer to the descriptions of the method embodiments of this application for understanding.

[0243] The aforementioned processor can be at least one of the following: application-specific integrated circuit (ASIC), digital signal processor (DSP), digital signal processing device (DSPD), programmable logic device (PLD), field-programmable gate array (FPGA), central processing unit (CPU), controller, microcontroller, and microprocessor. It is understood that other electronic devices can also implement the functions of the aforementioned processor, and this application does not specifically limit the specific implementation.

[0244] The aforementioned computer-readable storage medium / memory can be a read-only memory, a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a ferromagnetic random access memory (FRAM), a flash memory, a magnetic surface memory, an optical disc, or a compact disc read-only memory (CD ROM), etc.

[0245] This application provides a computer program including computer-readable code. When the computer-readable code runs in an electronic device, the processor in the electronic device executes some or all of the steps in the above-described method.

[0246] This application provides a computer program product, which includes a non-transitory computer-readable storage medium storing a computer program. When the computer program is read and executed by a computer, it implements some or all of the steps in the above-described method. This computer program product can be implemented specifically through hardware, software, or a combination thereof. In some embodiments, the computer program product is specifically embodied as a computer-readable storage medium; in other embodiments, the computer program product is specifically embodied as a software product, such as a software development kit (SDK), etc.

[0247] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in the various embodiments of this application, the sequence numbers of the above steps / processes do not imply a sequential order of execution; the execution order of each step / process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. The sequence numbers of the above embodiments of this application are merely descriptive and do not represent the superiority or inferiority of the embodiments.

[0248] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0249] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple units or components can be combined, or integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed can be through some interfaces, and the indirect coupling or communication connection between devices or units can be electrical, mechanical, or other forms.

[0250] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units. They may be located in one place or distributed across multiple network units. Some or all of the units may be selected to achieve the purpose of this embodiment according to actual needs.

[0251] In addition, each functional unit in the various embodiments of this application can be integrated into one processing unit, or each unit can be a separate unit, or two or more units can be integrated into one unit; the integrated unit can be implemented in hardware or in the form of hardware plus software functional units.

[0252] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium includes various media that can store program code, such as mobile storage devices, read-only memory (ROM), magnetic disks, or optical disks.

[0253] Alternatively, if the integrated units described above are implemented as software functional modules and sold or used as independent products, they can also be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence or the part that contributes to related technologies, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause an in-vehicle terminal (which may be a personal computer, server, or network device, etc.) to execute all or part of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as mobile storage devices, ROM, magnetic disks, or optical disks.

[0254] The above are merely embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

[0255] The above embodiments are merely preferred embodiments provided to fully illustrate this application, and the scope of protection of this application is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on this application are all within the scope of protection of this application.

Claims

1. A control method for a differential lock, characterized in that, Applied to vehicles including differential locks, the differential locks including excitation coils for converting electrical energy into electromagnetic force to control locking of the differential locks, the method includes: In response to the first command to activate the differential lock, the actual temperature of the excitation coil is obtained; Obtain the target locking torque of the differential lock; the target locking torque is matched with the current driving conditions of the vehicle; Based on the actual temperature and the target locking torque, determine the first drive current required for the differential lock to generate the target locking torque at the actual temperature; Based on the first driving current, the differential lock is controlled to lock.

2. The method according to claim 1, characterized in that, Obtaining the actual temperature of the excitation coil includes: Obtain the actual resistance value of the temperature-sensitive resistor installed in the differential lock near the excitation coil, and determine the actual temperature of the excitation coil based on the actual resistance value and the temperature change characteristics of the temperature-sensitive resistor; Alternatively, the oil temperature in the differential of the vehicle can be obtained, and the actual temperature of the excitation coil can be determined based on the oil temperature; the temperature of the excitation coil is positively correlated with the oil temperature; the differential lock is located in the differential.

3. The method according to claim 1 or 2, characterized in that, The step of determining the first drive current required for the differential lock to generate the target locking torque at the actual temperature, based on the actual temperature and the target locking torque, includes: The first driving current is determined based on the actual temperature, the target locking torque, and the first mapping relationship; Wherein, the first mapping relationship represents the temperature of the excitation coil, and the correspondence between the locking torque and the driving current of the differential lock.

4. The method according to claim 1 or 2, characterized in that, The step of determining the first drive current required for the differential lock to generate the target locking torque at the actual temperature, based on the actual temperature and the target locking torque, includes: Based on the target locking torque, determine the reference drive current required for the differential lock to generate the target locking torque at the reference temperature; The magnetic performance attenuation coefficient is determined based on the actual temperature of the excitation coil; Based on the actual temperature of the excitation coil, determine the actual resistance of the excitation coil at that actual temperature; The first driving current is determined based on the magnetic property attenuation coefficient, the actual resistance, and the reference driving current.

5. The method according to claim 1 or 2, characterized in that, The method further includes: In response to detecting that the vehicle is in a slipping state, a first prompt message is output to instruct the driver to operate a target switch to activate the differential lock; The system receives the driver's operation on the target switch and generates the first instruction.

6. The method according to claim 1 or 2, characterized in that, Obtaining the actual temperature of the excitation coil includes: If the differential lock is in the unlocked state, control the power supply circuit of the differential lock to be turned on, and obtain the actual temperature of the excitation coil; If the differential lock is in the locked state, a second prompt message is output to indicate that the differential lock has been activated.

7. The method according to claim 6, characterized in that, The step of obtaining the actual temperature of the excitation coil if the differential lock is in the unlocked state includes: Obtain the first driving parameters of the vehicle; If the differential lock is in the unlocked state and the first driving parameter meets the first condition, then the actual temperature of the excitation coil is obtained; The method further includes: if the differential lock is in the unlocked state and the first driving parameter does not meet the first condition, then outputting a third prompt message indicating that the differential lock cannot be activated; wherein the first condition is related to at least one of the vehicle's accelerator pedal opening, the vehicle's speed, the wheel speed difference between the left and right wheels of the vehicle, and the vehicle's steering angle.

8. The method according to claim 6, characterized in that, After controlling the differential lock to lock based on the drive current, the method further includes: Obtain the second driving parameters of the vehicle and / or the first actual current of the differential lock; Based on the second driving parameter and / or the first actual current of the differential lock, it is determined whether the locking condition is met; the locking condition includes the second driving parameter meeting a second condition and / or the first actual current of the differential lock meeting a first preset condition; wherein, the second condition is related to the wheel speed difference between the left and right wheels of the vehicle; If the locking condition is met, the differential lock is set to the locked state, and a fourth prompt message indicating that the differential lock is locked is output; if the locking condition is not met, the differential lock is set to the unlocked state, and a fifth prompt message indicating that the differential lock is not locked is output.

9. The method according to claim 8, characterized in that, After controlling the differential lock to be in a locked state, the method further includes: Obtain the third driving parameters of the vehicle; If the third driving parameter satisfies the third condition, the differential lock is unlocked; wherein the third condition is related to at least one of the wheel speed difference between the left and right wheels of the vehicle, the vehicle speed, and the vehicle steering angle. If the third driving parameter satisfies the fourth condition, the differential lock is maintained in a locked state based on the second driving current; the second driving current is less than the first driving current; wherein the fourth condition is related to at least one of the vehicle speed, the wheel speed difference between the left and right wheels of the vehicle, and the steering angle of the vehicle.

10. The method according to claim 9, characterized in that, The method further includes: In response to a second command to release the differential lock, the differential lock is controlled to unlock.

11. The method according to claim 9 or 10, characterized in that, The control of unlocking the differential lock includes: Set the differential lock drive current to a preset value; The method further includes: Obtain the second actual current of the differential lock; If the second actual current meets the second preset condition, the differential lock is set to the unlocked state, and a sixth prompt message is output; wherein, the sixth prompt message indicates that the differential lock has been unlocked and / or the reason for the differential lock being unlocked; if the second actual current does not meet the second preset condition, the differential lock is set to the fault state, and a seventh prompt message indicating the differential lock fault is output.

12. The method according to claim 11, characterized in that, After setting the differential lock to the unlocked state, the method further includes: Obtain the fourth driving parameter of the vehicle; If the fourth driving parameter meets the fifth condition, the power supply circuit of the differential lock is disconnected; if the fourth driving parameter does not meet the fifth condition, the state of the differential lock is set to fault state, and a seventh prompt message indicating the differential lock fault is output; wherein, the fifth condition is related to at least one of the vehicle speed, the wheel speed difference between the left and right wheels of the vehicle, and the steering angle of the vehicle.

13. A control device for a differential lock, characterized in that, Applied to vehicles including differential locks, the differential locks including excitation coils for converting electrical energy into electromagnetic force to control locking of the differential locks, comprising: The first acquisition unit is used to acquire the actual temperature of the excitation coil in response to the first command to activate the differential lock; The second acquisition unit is used to acquire the target locking torque of the differential lock; the target locking torque is matched with the current driving conditions of the vehicle; A determining unit is configured to determine, based on the actual temperature and the target locking torque, the first driving current required by the differential lock to generate the target locking torque at the actual temperature; The control unit is used to control the differential lock to lock based on the first drive current.

14. A vehicle, characterized in that, include: Differential locks and control devices; The control device includes one or more processors and a memory; The memory is used to store one or more programs that, when executed by the one or more processors, cause the device to implement the method as described in any one of claims 1 to 12.

15. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed by the computer's processor, causes the computer to perform the method according to any one of claims 1 to 12.

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