Differential lock control method and device

Abstract

The application relates to a differential lock control method and device, which comprises the following steps: obtaining a differential lock control signal; when the differential lock control signal is a middle axle shaft differential lock locking signal, obtaining front-rear axle speed difference value information, and when the front-rear axle speed difference value meets a preset condition, controlling the middle axle shaft differential lock to enter a locking state; or when the differential lock control signal is a middle axle wheel differential lock locking signal, controlling the middle axle wheel differential lock to enter a locking state according to first parameter information; or when the differential lock control signal is a middle axle wheel differential lock locking signal and a rear axle wheel differential lock locking signal, controlling the middle axle wheel differential lock and the rear axle wheel differential lock to enter a locking state according to second parameter information. In the embodiment of the application, the differential lock control signal is judged, the middle axle differential lock is controlled through an existing vehicle ESP system, the cost is reduced, and the differential lock control demand of a driver is better met according to a flexible strategy.

Description

Technical Field

[0001] This application relates to the field of vehicle control, and more particularly to a differential lock control method and device. Background Technology

[0002] The differential lock system is part of a vehicle's transmission system, and its main function is to ensure that the transmission system can provide sufficient traction under different road conditions. The drive axle differential lock is an essential component of off-road vehicles; when one wheel slips, it can transfer power to the other wheel, helping the vehicle get out of trouble.

[0003] Typically, automakers produce 4x4 off-road vehicles. To better meet different off-road needs, manufacturers have introduced 6x6 off-road vehicles (6 wheels, 3 axles). Compared to 4x4 off-road vehicles, 6x6 vehicles have one more axle and two more wheels at the rear, reducing the load on a single wheel and increasing the overall load-bearing capacity. The increased number of drive wheels and tires results in a larger tire contact area and more points of contact, allowing for more flexible power distribution and outstanding off-road capability in harsh road conditions. However, in current technology, 6x6 off-road vehicles cannot control the center axle differential lock through the vehicle's electronic stability system, leading to a reduction in vehicle safety performance. Summary of the Invention

[0004] To overcome the problems existing in related technologies, this application provides a differential lock control method and device.

[0005] According to a first aspect of the embodiments of this application, a differential lock control method is provided, applied to a series drive axle differential lock control system, the method comprising:

[0006] Obtain the differential lock control signal;

[0007] When the differential lock control signal is a locking signal for the inter-axle differential lock of the middle axle, the speed difference information between the front and rear axles is acquired. When the speed difference between the front and rear axles meets a preset condition, the inter-axle differential lock of the middle axle is controlled to enter the locking state; or...

[0008] When the differential lock control signal is a locking signal for the inter-wheel differential lock of the middle axle, the inter-wheel differential lock of the middle axle is controlled to enter the locking state according to the first parameter information; or...

[0009] When the differential lock control signal is the locking signal of the middle axle inter-wheel differential lock and the locking signal of the rear axle inter-wheel differential lock, the middle axle inter-wheel differential lock and the rear axle inter-wheel differential lock are controlled to enter the locking state according to the second parameter information.

[0010] Optionally, obtaining the front and rear axle speed difference information includes:

[0011] Obtain the output shaft speed of the transmission and the rear end speed of the drive shaft;

[0012] The difference between the front and rear axle speeds is generated based on the difference between the output shaft speed of the transmission and the rear end speed of the drive shaft.

[0013] Optionally, after the step of acquiring the differential lock control signal, the method further includes:

[0014] When the differential lock control signal is the locking signal of the middle axle inter-wheel differential lock, the state corresponding to the middle axle inter-axle differential lock and the state corresponding to the rear axle inter-wheel differential lock are obtained.

[0015] When the differential lock between the middle axle and the differential lock between the rear axle wheels are detected to be locked, the differential lock between the middle axle wheels is controlled to enter the locked state.

[0016] Optionally, the first parameter information includes vehicle speed information, brake pedal signal, and accelerator pedal signal; controlling the inter-wheel differential lock of the middle axle to enter the locking state according to the first parameter information includes:

[0017] The vehicle speed is determined based on the brake pedal signal and the accelerator pedal signal, and it is also determined whether the vehicle speed is less than a first preset value.

[0018] When it is detected that the wheel is in a braking state and the vehicle speed is less than a first preset value, the differential lock between the wheels of the middle axle is controlled to enter the locking state.

[0019] Optionally, the second parameter information includes the front and rear axle speed difference information, the vehicle speed information, and the rear axle wheel speed difference information; controlling the middle axle wheel differential lock and the rear axle wheel differential lock to enter the locking state according to the second parameter information includes:

[0020] When the front and rear axle speed difference information is detected to be less than a second preset value, the vehicle speed information is less than a third preset value, and the rear axle wheel speed difference information is less than a fourth preset value, the middle axle wheel differential lock and the rear axle wheel differential lock are controlled to enter the locking state.

[0021] Optionally, the method further includes:

[0022] If the differential lock between the axles of the middle axle or the differential lock between the wheels of the middle axle is detected to be locked and the vehicle speed reaches the target speed value, a warning message is sent to the vehicle controller.

[0023] Optionally, after the step of controlling the inter-wheel differential lock of the middle axle to enter the locked state, the method further includes:

[0024] If the vehicle speed information is detected to be greater than the target vehicle speed value, the inter-wheel differential lock of the middle axle will automatically unlock.

[0025] Optionally, after the step of controlling the inter-wheel differential lock of the middle axle to enter the locked state, the method further includes:

[0026] When the differential lock between the middle axle and the differential lock between the rear axle are detected to be in the unlocked state, the differential lock between the wheels of the middle axle is automatically unlocked.

[0027] Optionally, after the step of controlling the inter-wheel differential lock of the middle axle to enter the locked state when the inter-axle differential lock of the middle axle and the inter-wheel differential lock of the rear axle are in the locked state, the method further includes:

[0028] If the differential lock between the middle axle and the differential lock between the rear axle wheels are detected to be in an unlocked state, the differential lock between the middle axle wheels will automatically unlock.

[0029] According to a second aspect of the embodiments of this application, a differential lock control device is provided, the device comprising:

[0030] The acquisition module is used to acquire the differential lock control signal;

[0031] The control module is used to acquire the speed difference information between the front and rear axles when the differential lock control signal is a locking signal for the inter-axle differential lock of the middle axle; and to control the inter-axle differential lock of the middle axle to enter the locking state when the speed difference between the front and rear axles meets a preset condition; or...

[0032] When the differential lock control signal is a locking signal for the inter-wheel differential lock of the middle axle, the inter-wheel differential lock of the middle axle is controlled to enter the locking state according to the first parameter information; or...

[0033] When the differential lock control signal is the locking signal of the middle axle inter-wheel differential lock and the locking signal of the rear axle inter-wheel differential lock, the middle axle inter-wheel differential lock and the rear axle inter-wheel differential lock are controlled to enter the locking state according to the second parameter information.

[0034] The technical solutions provided by the embodiments of this application may include the following beneficial effects:

[0035] This application acquires a differential lock control signal; when the differential lock control signal is a locking signal for the inter-axle differential lock of the middle axle, it acquires the speed difference information between the front and rear axles, and when the speed difference between the front and rear axles meets a preset condition, it controls the inter-axle differential lock of the middle axle to enter the locking state; or, when the differential lock control signal is a locking signal for the inter-wheel differential lock of the middle axle, it controls the inter-wheel differential lock of the middle axle to enter the locking state according to a first parameter; or, when the differential lock control signal is a locking signal for both the inter-wheel differential lock of the middle axle and the inter-wheel differential lock of the rear axle, it controls both the inter-wheel differential lock of the middle axle and the inter-wheel differential lock of the rear axle to enter the locking state according to a second parameter. This invention determines the corresponding parameter information based on the differential lock control signal, thereby controlling the center axle differential lock to enter the locking state. This solves the problem that the existing technology cannot achieve center axle differential locking. Since the acquisition of the front and rear axle speed difference information is used as the judgment condition for controlling the center axle differential lock, it solves the problem that the existing technology cannot control the center axle differential lock because it cannot collect the center axle wheel speed using only four sensors. In this embodiment, by judging the differential lock control signal, the center axle differential lock can be controlled using only the four sensors in the existing vehicle ESP system. This reduces costs and, with flexible strategy configuration, better meets the driver's differential lock control needs.

[0036] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0037] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0038] Figure 1 This is a flowchart illustrating a differential lock control method according to an exemplary embodiment;

[0039] Figure 2 This is a schematic diagram illustrating the relative positions of a differential lock on a six-wheeled vehicle according to an exemplary embodiment;

[0040] Figure 3 This is a flowchart illustrating another differential lock control method according to an exemplary embodiment;

[0041] Figure 4 This is a flowchart illustrating another differential lock control method according to an exemplary embodiment;

[0042] Figure 5 This is a flowchart illustrating another differential lock control method according to an exemplary embodiment;

[0043] Figure 6 A block diagram of a differential lock control device is shown according to an exemplary embodiment. Detailed Implementation

[0044] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the invention as detailed in the appended claims.

[0045] The first embodiment of this application relates to a differential lock control method. Figure 1 This is a flowchart illustrating a differential lock control method according to an exemplary embodiment, such as... Figure 1 As shown, it includes the following steps:

[0046] Step 101: Obtain the differential lock control signal.

[0047] This embodiment applies to a series drive axle differential lock control system. The drive axle is a mechanism located at the end of the transmission system that can change the speed and torque from the transmission and transmit them to the drive wheels. The drive axle generally consists of a final drive, differential, wheel drive unit, and drive axle housing. When the drive shafts of the drive axles are connected in series and pass through the drive axle closest to the transfer case to another drive axle, the drive shaft must pass through the drive axle in this arrangement. This type of drive axle is called a series drive axle. The series drive axle differential lock system can be connected to various sensors and controllers in the vehicle to analyze, process, and judge the collected data and signals, and feed back the status of the differential lock to the instrument panel for status display. For example, when the inter-wheel differential lock of the middle axle is in the locked state, the indicator light of the corresponding inter-wheel differential lock of the middle axle on the instrument panel is red, and vice versa, it is green. The series drive axle differential lock control system continuously receives collected data and signals. When a differential lock control signal is detected, such as the differential lock locking signal between the middle axle shafts, the data signal is judged according to the preset locking conditions. If the conditions are met, the corresponding state of the differential lock is changed.

[0048] It should be noted that the axle (also called the vehicle axle) is connected to the frame (or monocoque body) via the suspension, and wheels are mounted at both ends. The vertical load on the frame is transmitted to the wheels through the axle; the rolling resistance, driving force, braking force, and lateral force on the wheels, as well as their bending moments and torques, are transmitted to the suspension and frame through the axle. Therefore, the function of the axle is to transmit the forces in all directions between the frame and the wheels and the resulting bending moments and torques. In this field, axles are usually classified as front axles, middle axles, and rear axles according to their relative positions on the vehicle. In this application, when a 6x6 off-road (6 wheels, 3 axles) vehicle is equipped with 5 differential locks, such as Figure 2 As shown, Figure 2 This is a schematic diagram illustrating the relative positions of differential locks in a six-wheeled vehicle according to an exemplary embodiment. 001 represents the front axle inter-wheel differential lock, primarily locking the left and right drive wheels of the front axle; 002 represents the transfer case center differential lock, primarily locking the differential lock that converts two-wheel drive to four-wheel drive; 003 represents the middle axle inter-axle differential lock, primarily locking the differential lock that converts four-wheel drive to six-wheel drive; 004 represents the middle axle inter-wheel differential lock, primarily locking the left and right drive wheels of the middle axle; 005 represents the rear axle inter-wheel differential lock, primarily locking the differential lock that converts the left and right drive wheels of the rear axle; 006 represents the transfer case; 007 represents the front driveshaft, primarily providing the rotational speed of the front end of the driveshaft; and 008 represents the rear driveshaft, primarily providing the rotational speed of the rear end of the driveshaft.

[0049] In this application, the differential lock control signals can be a central differential lock locking or disengaging signal, a front axle inter-wheel differential lock engaging or disengaging signal, a middle axle inter-axle differential lock engaging or disengaging signal, a middle axle inter-wheel differential lock engaging or disengaging signal, and a rear axle inter-wheel differential lock engaging or disengaging signal. Control of the differential locks is achieved based on these signals and corresponding data information, enabling the electronic stability control system (ESC). ESP (Electronic Stability Program) helps maintain vehicle dynamic balance by analyzing vehicle driving status information from various sensors. ESP can maintain optimal stability in various conditions, with more pronounced effects in cases of oversteer or understeer. Existing six-wheel drive models are extensions of four-wheel drive models, and product design needs to meet platform requirements. The ESP system in six-wheel drive models still uses four wheel speed sensors for data acquisition. If additional sensors are added to obtain the center axle wheel speed, it will significantly increase vehicle production costs. Therefore, the problem addressed in this application is that because the ESP system in six-wheel drive models only has four wheel speed sensors, the center axle cannot receive the center axle wheel speed signal, thus failing to lock the center axle differential lock. This application addresses the control of the center axle differential lock.

[0050] In this embodiment, the inter-wheel differential lock is mainly used to lock the inter-wheel differential, so that there is no speed difference between the left and right tires and they maintain synchronous operation. The inter-axle differential lock is mainly used to keep the middle axle and the rear axle running synchronously (that is, to change from two-wheel drive to four-wheel drive). In this application, the inter-wheel differential lock switch installed in the vehicle is used as one of the judgment conditions for locking the middle axle differential lock.

[0051] Step 102: When the differential lock control signal is the inter-axle differential lock locking signal, acquire the front and rear axle speed difference information; when the front and rear axle speed difference meets a preset condition, control the inter-axle differential lock to enter the locking state; or...

[0052] When the differential lock control signal is a locking signal for the inter-wheel differential lock of the middle axle, the inter-wheel differential lock of the middle axle is controlled to enter the locking state according to the first parameter information; or...

[0053] When the differential lock control signal is the locking signal of the middle axle inter-wheel differential lock and the locking signal of the rear axle inter-wheel differential lock, the middle axle inter-wheel differential lock and the rear axle inter-wheel differential lock are controlled to enter the locking state according to the second parameter information.

[0054] It should be noted that the embodiments in this application mainly include control methods for the inter-wheel differential lock of the central axle and control methods for the inter-axle differential lock of the central axle. Controlling the inter-axle differential lock to enter the locking state includes two methods: First, when the acquired differential lock control signal is the inter-axle differential lock locking signal, and the front and rear axle speed difference information meets a preset condition, the inter-axle differential lock is controlled to enter the locking state; when the acquired differential lock control signal is the inter-axle differential lock locking signal, the preset condition refers to the front and rear axle speed difference information being less than a preset value. When the front and rear axle speed difference information is detected to be less than the preset value, the inter-axle differential lock is controlled to enter the locking state; Second, the vehicle speed condition is limited by the type of differential lock. Generally, dog-clutch differential locks have high vehicle speed requirements, while electronic limited-slip differential locks do not. Therefore, when... When the inter-axle differential lock of the middle axle is a dog clutch type differential lock, the acquired differential lock control signal is the inter-axle differential lock locking signal of the middle axle. Based on the collected vehicle speed information, the front and rear axle speed difference information, and the pre-set first locking condition, the system determines whether the locking request is met. The inter-axle differential lock locking signal represents the differential lock mode currently requested by the driver. The inter-axle differential lock locking information is sent to the differential lock control system to confirm whether the locking request is met. Vehicle speed information is the condition for determining whether the inter-axle differential lock is locked. Since the middle axle has no wheel speed information, this vehicle speed is converted from the front and rear axle wheel speeds and used as the vehicle speed information. The front and rear axle speed difference information is used because the middle axle has no wheel speed information. In actual use (e.g., driving on uneven roads when the middle axle is suspended), the difference between the speed of the transmission output shaft and the speed of the rear end of the drive shaft is used as the locking condition for determining whether the inter-axle lock is engaged.

[0055] It should be noted that the preset values ​​in this application embodiment are not specifically limited. For example, the preset vehicle speed value can be a fixed value preset before the vehicle leaves the factory according to the specific conditions of the vehicle. Similarly, the preset difference value can also be a fixed value preset before the vehicle leaves the factory according to the specific conditions of the vehicle.

[0056] Further, in step 102, obtaining the front and rear axle speed difference information includes:

[0057] Obtain the output shaft speed of the transmission and the rear end speed of the drive shaft; generate front and rear axle speed difference information based on the difference between the output shaft speed of the transmission and the rear end speed of the drive shaft.

[0058] It should be noted that the vehicle transmission system mainly consists of a gearbox, front and rear drive shafts, axle bearings, a front main shaft, and a rear wheel axle. The gearbox includes an output shaft and an input shaft, and the drive shafts include a front drive shaft and a rear drive shaft. Therefore, the speed of the gearbox output shaft and the speed of the rear end of the drive shaft can be obtained. The difference between the gearbox output shaft speed and the speed of the rear end of the drive shaft is used to generate the front and rear axle speed difference information. This information is used as one of the locking conditions for determining the locking between the axle shafts.

[0059] In addition, when the driver sends a signal to the differential lock control system to close the inter-axle differential lock, the inter-axle differential lock will automatically unlock.

[0060] There are three control methods for controlling the inter-wheel differential lock of the central axle. The first method is a separate central axle inter-wheel differential lock switching strategy. When the differential lock control signal is the central axle inter-wheel differential lock locking signal, the central axle inter-wheel differential lock is controlled to enter the locking state according to the first parameter information. Further, in step 102, the first parameter information includes vehicle speed information, brake pedal signal, and accelerator pedal signal; the step of controlling the central axle inter-wheel differential lock to enter the locking state according to the first parameter information includes:

[0061] The vehicle speed is determined based on the brake pedal signal and the accelerator pedal signal, and it is also determined whether the vehicle speed is less than a first preset value.

[0062] When it is detected that the wheel is in a braking state and the vehicle speed is less than a first preset value, the differential lock between the wheels of the middle axle is controlled to enter the locking state.

[0063] It should be noted that when the acquired differential lock control signal is the center axle inter-wheel differential lock locking signal, it represents the differential lock mode currently requested by the driver. The center axle inter-wheel differential lock locking signal is sent to the differential lock control system to confirm whether the locking request is met. Therefore, in the first case, when the vehicle is equipped with five differential lock switches, when the center axle inter-wheel differential lock is locked alone, the system uses the brake pedal signal, vehicle speed signal, and accelerator pedal signal to determine whether the center axle inter-wheel differential lock can be locked. When the brake signal is open, the accelerator pedal signal is closed, and the vehicle speed is less than the preset value, it indicates that the vehicle is in a stopped state. Pressing the center axle inter-wheel differential lock switch can lock the center axle inter-wheel differential lock, effectively preventing gear breakage caused by locking the inter-wheel differential lock when the vehicle's center axle is suspended or one wheel is slipping.

[0064] In addition, when the driver sends a signal to the differential lock control system to close the center axle wheel differential lock, the center axle wheel differential lock will automatically unlock.

[0065] There are three control methods for controlling the inter-wheel differential lock of the middle axle. The second method is a control strategy for the inter-wheel differential lock of the middle axle and the rear axle. When the differential lock control signal is a locking signal for both the middle axle and the rear axle inter-wheel differential lock, the inter-wheel differential lock of the middle axle and the rear axle are controlled to enter the locking state according to the second parameter information. That is, at this time, the inter-wheel differential lock of the middle axle and the rear axle can be treated as a whole, and a single switch controls the inter-wheel differential lock of the middle axle and the rear axle. Alternatively, the locking signals of the inter-wheel differential lock of the middle axle and the rear axle can be acquired simultaneously. Further, in step 102, the second parameter information includes the front and rear axle speed difference information, the vehicle speed information, and the rear axle inter-wheel speed difference information. The step of controlling the inter-wheel differential lock of the middle axle and the rear axle to enter the locking state according to the second parameter information includes:

[0066] When the detected front-to-rear axle speed difference is less than a second preset value, the vehicle speed is less than a third preset value, and the rear axle wheel speed difference is less than a fourth preset value, the differential locks of the middle axle and the rear axle are controlled to enter the locking state. For example, when the front-to-rear axle speed difference is less than 50 rpm, the vehicle speed is less than 5 km / h, and the rear axle wheel speed difference is less than 50 rpm, and all of the above conditions are met, pressing the differential lock switches of the middle axle and the rear axle will lock the differential locks of the middle axle and the rear axle simultaneously. The specific values ​​mentioned above are not specifically limited in this application, and a fixed value is preset according to the size, shape, and configuration of different vehicles.

[0067] In addition, in the second strategy, besides the automatic unlocking of the inter-wheel differential lock when the driver sends a signal to the differential lock control system to close the inter-wheel differential lock, the inter-wheel differential lock can also unlock accordingly. Specifically, the inter-wheel differential lock can automatically unlock when it is detected that the inter-axle differential lock and the rear axle differential lock are in an unlocked state, and the inter-wheel differential lock can also unlock accordingly.

[0068] This application acquires a differential lock control signal; when the differential lock control signal is a locking signal for the inter-axle differential lock of the middle axle, it acquires the speed difference information between the front and rear axles, and when the speed difference between the front and rear axles meets a preset condition, it controls the inter-axle differential lock of the middle axle to enter the locking state; or, when the differential lock control signal is a locking signal for the inter-wheel differential lock of the middle axle, it controls the inter-wheel differential lock of the middle axle to enter the locking state according to a first parameter; or, when the differential lock control signal is a locking signal for both the inter-wheel differential lock of the middle axle and the inter-wheel differential lock of the rear axle, it controls both the inter-wheel differential lock of the middle axle and the inter-wheel differential lock of the rear axle to enter the locking state according to a second parameter. The technical solution provided by the embodiments of this application solves the problem that the ESP system of a six-wheel drive vehicle only has four wheel speed sensors, which cannot simultaneously realize the wheel speed signal acquisition function of the six-wheel vehicle. As a result, the middle axle cannot receive the wheel speed signal, and thus the middle axle differential lock cannot be locked. The embodiments of this application judge the differential lock control signal, so as to realize the control of the middle axle differential lock only through the four sensors in the existing vehicle ESP system. While reducing costs, it can better meet the driver's differential lock control needs according to flexible strategy configuration.

[0069] The second embodiment of this application relates to a differential lock control method. Figure 3 This is a flowchart illustrating another differential lock control method according to an exemplary embodiment, such as... Figure 3 As shown, it includes the following steps:

[0070] Step 101: Obtain the differential lock control signal;

[0071] Step 102: When the differential lock control signal is the inter-axle differential lock locking signal, acquire the front and rear axle speed difference information; when the front and rear axle speed difference meets a preset condition, control the inter-axle differential lock to enter the locking state; or...

[0072] When the differential lock control signal is a locking signal for the inter-wheel differential lock of the middle axle, the inter-wheel differential lock of the middle axle is controlled to enter the locking state according to the first parameter information; or...

[0073] When the differential lock control signal is the locking signal of the middle axle inter-wheel differential lock and the locking signal of the rear axle inter-wheel differential lock, the middle axle inter-wheel differential lock and the rear axle inter-wheel differential lock are controlled to enter the locking state according to the second parameter information.

[0074] Steps 101-102 above are discussed in the preceding paragraphs and will not be repeated here.

[0075] Step 103: When the differential lock control signal is the inter-wheel differential lock locking signal of the middle axle, obtain the state corresponding to the inter-axle differential lock of the middle axle and the state corresponding to the inter-wheel differential lock of the rear axle.

[0076] Step 104: When it is detected that the middle axle inter-axle differential lock and the rear axle inter-wheel differential lock are in a locked state, control the middle axle inter-wheel differential lock to enter the locked state.

[0077] It should be noted that steps 103-104 are for controlling the inter-wheel differential lock of the middle axle using a third control method. Specifically, when the differential lock control signal is the inter-wheel differential lock locking signal of the middle axle, the inter-wheel differential lock of the middle axle can be locked when the inter-axle differential lock and the inter-wheel differential lock of the rear axle are simultaneously locked.

[0078] Step 105: If the differential lock between the middle axle and the differential lock between the rear axle wheels are detected to be in an unlocked state, the differential lock between the middle axle wheels will be automatically unlocked.

[0079] It should be noted that after the middle axle inter-wheel differential lock is engaged, if either the middle axle inter-axle differential lock or the rear axle inter-wheel differential lock is unlocked, the middle axle inter-wheel differential lock can be unlocked accordingly.

[0080] The above-mentioned 6x6 off-road vehicle center axle differential lock control strategy fills the gap in the lack of a 6x6 off-road vehicle center axle differential lock control strategy. It solves the problem that because the ESP system of a six-wheel drive vehicle only has four wheel speed sensors, it cannot simultaneously realize the wheel speed signal acquisition function of all six wheels, which leads to the center axle not receiving the center axle wheel speed signal, and thus cannot realize the center axle wheel differential lock locking.

[0081] The third embodiment of this application relates to a differential lock control method. Figure 4 This is a flowchart illustrating another differential lock control method according to an exemplary embodiment, such as... Figure 4 As shown, it includes the following steps:

[0082] Step 101: Obtain the differential lock control signal;

[0083] Step 102: When the differential lock control signal is the inter-axle differential lock locking signal, acquire the front and rear axle speed difference information; when the front and rear axle speed difference meets a preset condition, control the inter-axle differential lock to enter the locking state; or...

[0084] When the differential lock control signal is a locking signal for the inter-wheel differential lock of the middle axle, the inter-wheel differential lock of the middle axle is controlled to enter the locking state according to the first parameter information; or...

[0085] When the differential lock control signal is the locking signal of the middle axle inter-wheel differential lock and the locking signal of the rear axle inter-wheel differential lock, the middle axle inter-wheel differential lock and the rear axle inter-wheel differential lock are controlled to enter the locking state according to the second parameter information.

[0086] Steps 101-102 above are discussed in the preceding paragraphs and will not be repeated here.

[0087] Step 106: When the differential lock between the axles of the middle axle or the differential lock between the wheels of the middle axle is detected to be locked and the vehicle speed information reaches the target vehicle speed value, a warning message is sent to the vehicle controller.

[0088] It should be noted that when the differential lock is engaged, the front / rear wheels will feel a dragging sensation when turning on paved roads. This will shorten the lifespan of the differential lock and, in severe cases, damage transmission system components. Therefore, its use on paved roads is prohibited. When the center differential lock, the middle axle inter-axle differential lock, the middle axle wheel inter-lock, the rear axle wheel inter-lock, and the front axle wheel inter-lock are all engaged simultaneously, the entire vehicle is in a rigidly connected state. The front axle steering drive axle experiences steering braking, understeering, and a large steering torque, which affects the safety of the entire vehicle. Therefore, it is necessary to drive at low speeds within a safe range.

[0089] Therefore, whether it is the inter-axle differential lock or the inter-wheel differential lock of the middle axle, when the differential lock is in the locked state, the differential lock control system will continuously monitor the speed of the target vehicle. If the vehicle speed is detected to be greater than the preset value, a warning message will be sent to the vehicle control. For example, when the differential lock is in the locked state, if the vehicle speed reaches the specified speed, the differential lock is in the locked state. At this time, the differential lock switch and the instrument indicator light will flash to prompt the driver to reduce the vehicle speed.

[0090] This application embodiment sends a warning message to the vehicle controller when the vehicle speed reaches the target speed value after detecting that the inter-axle differential lock or the inter-wheel differential lock of the middle axle is locked. That is, while controlling the middle axle differential lock, the vehicle speed is collected in real time and the target value is judged, so as to ensure the driving safety of the vehicle when the differential lock needs to participate in the vehicle operation.

[0091] The fourth embodiment of this application relates to a differential lock control method. Figure 5 This is a flowchart illustrating another differential lock control method according to an exemplary embodiment, such as... Figure 5 As shown, it includes the following steps:

[0092] Step 101: Obtain the differential lock control signal;

[0093] Step 102: When the differential lock control signal is the inter-axle differential lock locking signal, acquire the front and rear axle speed difference information; when the front and rear axle speed difference meets a preset condition, control the inter-axle differential lock to enter the locking state; or...

[0094] When the differential lock control signal is a locking signal for the inter-wheel differential lock of the middle axle, the inter-wheel differential lock of the middle axle is controlled to enter the locking state according to the first parameter information; or...

[0095] When the differential lock control signal is the locking signal of the middle axle inter-wheel differential lock and the locking signal of the rear axle inter-wheel differential lock, the middle axle inter-wheel differential lock and the rear axle inter-wheel differential lock are controlled to enter the locking state according to the second parameter information.

[0096] Steps 101-102 above are discussed in the preceding paragraphs and will not be repeated here.

[0097] Step 107: If the vehicle speed information is detected to be greater than the target vehicle speed value, the inter-wheel differential lock of the middle axle is automatically unlocked.

[0098] It should be noted that the differential lock between the wheels of the middle axle can be unlocked when overspeeding. That is, when the vehicle speed exceeds the specified speed, the differential lock will automatically unlock, and when the vehicle speed drops back below the specified speed after the overspeed unlock, the differential lock will not automatically lock again.

[0099] This application acquires a differential lock control signal; when the differential lock control signal is a locking signal for the inter-axle differential lock of the middle axle, it acquires the speed difference information between the front and rear axles, and when the speed difference between the front and rear axles meets a preset condition, it controls the inter-axle differential lock of the middle axle to enter the locking state; or, when the differential lock control signal is a locking signal for the inter-wheel differential lock of the middle axle, it controls the inter-wheel differential lock of the middle axle to enter the locking state according to a first parameter; or, when the differential lock control signal is a locking signal for both the inter-wheel differential lock of the middle axle and the inter-wheel differential lock of the rear axle, it controls both the inter-wheel differential lock of the middle axle and the inter-wheel differential lock of the rear axle to enter the locking state according to a second parameter. This method determines the corresponding parameter information based on the differential lock control signal, thereby controlling the center axle differential lock to enter the locking state. This solves the problem that the existing technology cannot achieve center axle differential locking. Since the obtained front and rear axle speed difference information is used as the judgment condition for controlling the center axle differential lock, it solves the problem that the existing technology cannot control the center axle differential lock based on wheel speed due to the inability to collect wheel speed. The technical solution provided by the embodiments of this application solves the problem that because the ESP system of a six-wheel drive vehicle only has four wheel speed sensors, it cannot simultaneously realize the wheel speed signal acquisition function of a six-wheel vehicle, resulting in the center axle not receiving the center axle wheel speed signal, and thus the inability to achieve center axle differential lock locking.

[0100] It should be noted that all embodiments in this example are only for the purpose of enabling those skilled in the art to better understand the technical solutions in this example, and are not intended to limit the structure of the differential lock in this example.

[0101] The fifth embodiment of this application relates to a differential lock control device, such as... Figure 6 As shown, Figure 6 This is a block diagram of a differential lock control device according to an exemplary embodiment, the device including the following modules:

[0102] The acquisition module 601 is used to acquire the differential lock control signal;

[0103] Control module 602 is used to acquire the front and rear axle speed difference information when the differential lock control signal is the inter-axle differential lock locking signal of the middle axle; and control the inter-axle differential lock of the middle axle to enter the locking state when the front and rear axle speed difference meets a preset condition; or...

[0104] When the differential lock control signal is a locking signal for the inter-wheel differential lock of the middle axle, the inter-wheel differential lock of the middle axle is controlled to enter the locking state according to the first parameter information; or...

[0105] When the differential lock control signal is a locking signal for both the middle axle inter-wheel differential lock and the rear axle inter-wheel differential lock, the middle axle inter-wheel differential lock and the rear axle inter-wheel differential lock are controlled to enter the locking state according to the second parameter information. Regarding the device in the above embodiments, the specific methods by which each module performs its operation have been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0106] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0107] It should be noted that the above embodiments are illustrative of the invention and not restrictive, and that alternative embodiments can be devised by those skilled in the art without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names. The invention is not limited to the precise structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A method for controlling a differential lock, applied to a tandem drive axle differential lock control system, characterized in that, The method comprises: acquiring a differential lock control signal; when the differential lock control signal is a middle axle differential lock locking signal, acquiring front-rear axle speed difference information, and when the front-rear axle speed difference meets a preset condition, controlling the middle axle differential lock to enter a locking state, wherein the middle axle differential lock is a differential lock locking mechanism for changing four-wheel drive to six-wheel drive; or, when the differential lock control signal is a middle axle wheel differential lock locking signal, controlling the middle axle wheel differential lock to enter the locking state according to first parameter information; or, when the differential lock control signal is a middle axle wheel differential lock locking signal and a rear axle wheel differential lock locking signal, controlling the middle axle wheel differential lock and the rear axle wheel differential lock to enter the locking state according to second parameter information; wherein the acquiring front-rear axle speed difference information comprises: acquiring a transmission output shaft speed and a drive shaft rear end speed; generating front-rear axle speed difference information according to the difference between the transmission output shaft speed and the drive shaft rear end speed; wherein the first parameter information comprises vehicle speed information, brake pedal signal and accelerator pedal signal; the controlling the middle axle wheel differential lock to enter the locking state according to the first parameter information comprises: judging the wheel running state according to the brake pedal signal and the accelerator pedal signal, and judging whether the vehicle speed information is less than a first preset value; when the wheel running state is detected to be in a braking state and the vehicle speed information is detected to be less than the first preset value, controlling the middle axle wheel differential lock to enter the locking state; the second parameter information comprises the front-rear axle speed difference information, the vehicle speed information and rear axle wheel differential lock speed difference information; the controlling the middle axle wheel differential lock and the rear axle wheel differential lock to enter the locking state according to the second parameter information comprises: when the front-rear axle speed difference information is detected to be less than a second preset value, the vehicle speed information is detected to be less than a third preset value, and the rear axle wheel differential lock speed difference information is detected to be less than a fourth preset value, controlling the middle axle wheel differential lock and the rear axle wheel differential lock to enter the locking state.

2. The method of claim 1, wherein, After the step of acquiring the differential lock control signal, the method further comprises: when the differential lock control signal is a middle axle wheel differential lock locking signal, acquiring the state corresponding to the middle axle differential lock and the state corresponding to the rear axle differential lock; when the middle axle differential lock and the rear axle differential lock are detected to be in the locking state, controlling the middle axle wheel differential lock to enter the locking state.

3. The method of claim 1, wherein, The method further comprises: when the middle axle differential lock or the middle axle wheel differential lock is detected to be in the locking state and the vehicle speed information reaches a target vehicle speed value, sending a warning information to a vehicle controller.

4. The method of claim 1, wherein, After the step of controlling the middle axle wheel differential lock to enter the locking state, the method further comprises: when the vehicle speed information is detected to be greater than the target vehicle speed value, the middle axle wheel differential lock is automatically unlocked.

5. The method of claim 1, wherein, After the step of controlling the middle axle wheel differential lock and the rear axle wheel differential lock to enter the locking state, the method further comprises: In the case that the inter-axle differential lock of the middle axle and the inter-axle differential lock of the rear axle are in the unlocked state, the inter-wheel differential lock of the middle axle is automatically unlocked.

6. The method of claim 2, wherein, In the case that the inter-axle differential lock of the middle axle and the inter-axle differential lock of the rear axle are in the locked state, the method further comprises the following step after the step of controlling the inter-wheel differential lock of the middle axle to be in the locked state: In the case that the inter-axle differential lock of the middle axle and the inter-axle differential lock of the rear axle are in the unlocked state, the inter-wheel differential lock of the middle axle is automatically unlocked.

7. A differential lock control device characterized by, The device comprises: an acquisition module configured to acquire a differential lock control signal; a control module configured to, when the differential lock control signal is an inter-axle differential lock locking signal of the middle axle, acquire front-rear axle speed difference information, and control the inter-axle differential lock of the middle axle to be in a locked state when the front-rear axle speed difference satisfies a preset condition, wherein the inter-axle differential lock of the middle axle is a differential lock locking mechanism for changing four-wheel drive into six-wheel drive; or when the differential lock control signal is an inter-wheel differential lock locking signal of the middle axle, control the inter-wheel differential lock of the middle axle to be in the locked state according to first parameter information; or when the differential lock control signal is an inter-wheel differential lock locking signal of the middle axle and an inter-wheel differential lock locking signal of the rear axle, control the inter-wheel differential lock of the middle axle and the inter-wheel differential lock of the rear axle to be in the locked state according to second parameter information; wherein the acquisition of the front-rear axle speed difference information comprises: acquiring a transmission output shaft speed and a rear end of a transmission shaft speed; generating front-rear axle speed difference information according to the difference between the transmission output shaft speed and the rear end of the transmission shaft speed; wherein the first parameter information comprises vehicle speed information, brake pedal signal and accelerator pedal signal; and the control of the inter-wheel differential lock of the middle axle to be in the locked state according to the first parameter information comprises: judging a wheel running state according to the brake pedal signal and the accelerator pedal signal, and judging whether the vehicle speed information is less than a first preset value; controlling the inter-wheel differential lock of the middle axle to be in the locked state when the wheel running state is in a braking state and the vehicle speed information is less than the first preset value; the second parameter information comprises the front-rear axle speed difference information, the vehicle speed information and rear inter-wheel speed difference information; and the control of the inter-wheel differential lock of the middle axle and the inter-wheel differential lock of the rear axle to be in the locked state according to the second parameter information comprises: controlling the inter-wheel differential lock of the middle axle and the inter-wheel differential lock of the rear axle to be in the locked state when the front-rear axle speed difference information is less than a second preset value, the vehicle speed information is less than a third preset value and the rear inter-wheel speed difference information is less than a fourth preset value.

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