A loader multi-mode automatic gear shifting control method, system and loader

Abstract

This invention belongs to the field of loader shift control technology, specifically relating to a multi-mode automatic shift control method, system, and loader for loader operation. The system starts and switches to automatic mode; the driver manually selects loading, relocation, or combined mode; real-time acquisition of engine speed, output shaft speed, and throttle opening signals is sent to the transmission electronic control unit; pre-stored shift parameter curves corresponding to the selected mode are called; the system determines whether shift conditions are met based on the current throttle and vehicle speed; if so, the hydraulic actuator is controlled to complete the shift. The system can return to the selected mode at any time during operation and then operate according to the new parameter curve. By pre-setting multiple targeted shift curves and supporting real-time switching by the driver, the loader can automatically adapt to different working conditions such as loading and relocation, improving both operational power and relocation economy. The combined mode intelligently integrates the advantages of both modes based on throttle opening, improving overall machine operating efficiency and transmission system durability.

Description

Technical Field

[0001] This invention belongs to the field of loader shift control technology, specifically relating to a multi-mode automatic shift control method, system, and loader for a loader. Background Technology

[0002] Loaders, as key construction machinery in infrastructure and other energy projects, operate in complex and varied environments, requiring frequent switching between loading, transferring, and unloading. Currently, to reduce driver workload, loaders are being equipped with automatic gear shifting modes, which both reduce driver fatigue and improve work efficiency.

[0003] However, in related technologies, shifting modes does not require first cutting off power transmission; the driver can switch modes directly while the gear is in operation. At this time, the power system is still in gear engagement, and the shifting parameters and control signals of the old and new modes conflict with each other. This causes erratic operation of the hydraulic actuator, asynchronous clutch engagement and disengagement, and severe shocks to the transmission, potentially damaging gears and clutches. Furthermore, if the parameters of the original mode are not reset during mode switching, residual parameters such as the original shift curve, timer, and solenoid valve opening will prevent the control signals of the new mode from taking effect accurately, leading to abnormal shifting actions and problems such as shifting jamming and power interruption.

[0004] The related technology suffers from unstable gear shifting, mechanical wear, and noticeable shift shock. The existing hydraulic actuator's solenoid valve assembly lacks coordinated control logic, resulting in asynchronous operation of the inlet and outlet solenoid valves. This causes sudden changes in oil pressure in the shift clutch, leading to hard contact during clutch engagement and excessive pressure release during disengagement, generating a strong shift shock. This not only affects the driver's operating experience but also causes rapid wear of the clutch friction plates, uneven stress on the gears inside the transmission, and long-term use can result in clutch slippage and poor gear meshing. Summary of the Invention

[0005] This invention provides a multi-mode automatic gear shifting control method for loaders. It achieves working condition adaptation through targeted mode design, improves shifting accuracy through pre-stored curves and adaptive recall, reduces misjudgment through hysteresis interval and timer mechanism, optimizes smoothness through hydraulic closed-loop control, and ensures switching safety through working condition limitations and self-checking process, ultimately improving work efficiency and transmission system reliability.

[0006] The methods include: S1. Start the loader and switch the gear shift mode to automatic mode; S2. Select the target shifting mode through the mode switching module. The mode switching module includes a mode switching switch and a mode display unit. The mode display unit displays the currently selected target shifting mode in real time. The target shifting mode includes loading mode, transfer mode or comprehensive mode. S3. Collect the engine speed, output shaft speed and throttle opening operation signals of the loader and send them to the transmission electronic control unit; S4. The transmission electronic control unit calls the pre-stored shift parameter curve corresponding to the target shift mode. S5. Based on the shift parameter curve called and the signal collected in step S3, determine whether the conditions for shifting up or down are met. S6. If the conditions for shifting gears are met, the transmission electronic control unit controls the hydraulic actuator to perform the shifting action; the gear shifting action is completed by controlling the disengagement and engagement of the clutch. S7. During operation, if it is necessary to switch the shift mode, return to step S2 to reselect the target shift mode, and repeat the process of steps S3 to S6 to perform automatic shift control based on the new target shift mode.

[0007] According to another embodiment of this application, a multi-mode automatic gear shifting control system for a loader is provided, the system including: a mode switching module, a mode display unit, and a gearbox electronic control unit; The gear shifting module is used to start the loader and switch the gear shifting mode to automatic mode; The mode switching module selects the target shift mode. The mode switching module includes a mode switching switch and a mode display unit. The mode display unit displays the currently selected target shift mode in real time. The target shift mode includes loading mode, transfer mode or comprehensive mode; it collects the loader's operating signals and sends them to the transmission electronic control unit. The transmission electronic control unit calls the pre-stored shift parameter curve corresponding to the target shift mode; based on the called shift parameter curve and the collected operating signals, it determines whether the conditions for upshifting or downshifting have been met. If the conditions for shifting gears are met, the transmission control unit controls the hydraulic actuator to perform the shifting action; it also completes the shifting action by controlling the disengagement and engagement of the clutch. During operation, if it is necessary to switch the shift mode and reselect the target shift mode, the above process should be repeated to perform automatic shift control based on the new target shift mode.

[0008] According to another embodiment of this application, a loader is also provided, including a memory, a processor, and a computer system stored in the memory and operable on the processor, wherein the processor executes the steps of the multi-mode automatic gear shifting control method for the loader when executing the system.

[0009] As can be seen from the above technical solutions, the present invention has the following advantages: The multi-mode automatic shifting control method for loaders provided by this invention sets three target shifting modes: shoveling, transfer, and combined. The mode display unit provides real-time feedback on the current mode for easy driver confirmation. The transmission electronic control unit (ECU) pre-stores dedicated shifting parameter curves for each mode: shoveling mode corresponds to the traction force-vehicle speed curve at various throttle openings; transfer mode corresponds to the torque converter efficiency-vehicle speed curve at various throttle openings; and the combined mode corresponds to a hybrid shifting curve dynamically adjusted with throttle opening. The ECU retrieves the corresponding curve based on the driver's selected target mode, adapting to different working conditions. It can dynamically balance power and efficiency according to throttle opening, achieving optimal shifting control in different operating scenarios, thus improving operational adaptability and efficiency.

[0010] This invention sets the prerequisite for mode switching as follows: the shift lever must be returned to the neutral position. The driver must first move the shift lever to the neutral position to cut off power transmission and generate a neutral signal. A new target mode is selected via the instrument cluster's secondary menu, generating a mode selection signal. Both signals are transmitted synchronously to the electronic control unit (ECU). After confirming the two signals, the ECU checks for any incomplete shift actions. If no incomplete actions are found, all parameters of the original mode are reset, the new mode curve is retrieved, and the control process is re-executed. This avoids mechanical shock caused by mode switching during power transmission, protects the gearbox gears and clutch, reduces component wear, and improves the safety and rationality of mode switching.

[0011] The electronic control unit of this invention generates a PWM control signal corresponding to the upshift / downshift direction based on the shift determination result. The signal duty cycle is adjusted according to the target shift mode; a higher duty cycle is used for the shoveling mode to adapt to rapid shifting, while a lower duty cycle is used for the transfer mode to adapt to smooth shifting. The inlet and outlet solenoid valves of the gearbox proportional solenoid valve group work together to adjust the hydraulic oil flow and pressure at a preset rate, achieving smooth oil pressure rise and fall. During shifting, the clutch of the current gear is first fully disengaged, and then the clutch of the target gear is linearly pressurized and engaged until the working oil pressure is reached. The shifting process is smooth and shock-free, with smooth clutch engagement and disengagement, extending the service life of the clutch friction plates and gearbox gears. Hydraulic closed-loop control ensures precise oil pressure regulation, strong consistency between different shifting actions, and improved operational smoothness.

[0012] The electronic control unit retrieves the shift parameter curve corresponding to the target mode and, combined with the real-time acquired output shaft speed signal and throttle opening signal, matches the theoretical shift point within the corresponding throttle opening range. The shift trigger state is continuously confirmed; only when the trigger state is continuously satisfied and the anti-vibration time is reached is the shift condition determined to be met. The shift timing precisely matches the driver's power needs and the vehicle's operating status. Upshifts result in smooth power delivery without interruption or waste, downshifts are smooth without vehicle jerking, power is promptly supplied during loading, and efficient operation is maintained during site transfers, improving operational efficiency. Attached Figure Description

[0013] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 A schematic diagram of the shift points for each of the F1-F2 modes; Figure 2 A schematic diagram of the shift points for each of the F2-F3 modes; Figure 3 A schematic diagram of the shift points for each mode from F3 to F4; Figure 4 Flowchart of an embodiment of the multi-mode automatic gear shifting control method for loaders; Figure 5 Flowchart of the multi-mode automatic gear shifting control method for loaders; Figure 6 This is a schematic diagram of a loader. Detailed Implementation

[0015] The relevant terms used in the multi-mode automatic gear shifting control method for loaders provided by this invention are explained as follows: Hydraulic torque converter: The hydraulic torque converter is the core component of hydraulic transmission. It consists of components such as turbine, pump wheel, and guide wheel. It is matched with the engine and transmission to achieve flexible power transmission, automatic torque conversion and overload protection.

[0016] Transmission: The transmission is the core component of the power transmission system, which changes speed and direction. It works with the hydraulic torque converter and drive axle to realize the speed regulation, direction switching, power interruption and torque amplification of the loader. The mainstream types are fixed-shaft power shift transmissions and planetary power shift transmissions.

[0017] Loading mode: The loader is in a heavy-load working state, usually transporting materials over short distances in confined spaces, and performing shoveling and loading operations.

[0018] Relocation mode: This is a common working mode for loaders when they finish their work or need to change sites. It usually involves traveling long distances unloaded.

[0019] Comprehensive mode: The loader has a large working area, which requires both loading and transportation within the site.

[0020] The method selects the current automatic shifting mode through a mode selection switch. During operation, the transmission electronic control unit collects engine speed, output shaft speed and accelerator pedal opening signals in real time through sensors. When the output shaft speed reaches the shifting condition of the current mode, the vehicle performs a shifting action.

[0021] Specifically, such as Figure 4 As shown, the engine's external characteristic curve is obtained based on the engine parameters of the entire vehicle, and the torque converter characteristic curve is obtained based on the torque converter parameters. The torque converter efficiency corresponding to the torque converter speed ratio is obtained from the torque converter characteristic curve. Based on the turbine torque in the torque converter characteristic curve, the traction force-vehicle speed curve and torque converter efficiency-vehicle speed curve for each gear at different throttle openings are obtained. For the shoveling mode, the traction force-vehicle speed curves for each gear are placed on the same coordinate axis, and the intersection of the curves for each gear is the preset shift point. For the relocation mode, the torque converter efficiency-vehicle speed curves for each gear are placed on the same coordinate axis, and the intersection of the curves for each gear is the preset shift point. For... In summary, the overall design needs to consider the characteristics of both loading and relocation modes. For low throttle openings (below 30%), where less power is needed, the shift points are based on relocation mode. For high throttle openings (above 70%), where greater power is required, the shift points are based on loading mode. For medium throttle openings (30%-70%), both relocation and loading conditions need to be considered. Within this throttle range, the shift points are determined by the throttle opening itself, prioritizing the proportion of loading and relocation mode shift points. A larger throttle opening results in a larger proportion of loading mode shift points. The final shift points within the throttle range are calculated using a proportional coefficient. (Appendix) Figure 1 The shift curves for each mode (F1-F2) are attached. Figure 2 The shift curves for each mode from F2 to F3 are attached. Figure 3 The curves for shift points in each of the F3-F4 modes.

[0022] The following will describe in detail the multi-mode automatic gear shifting control method for loaders involved in this application. Specific details such as particular system structures and technologies are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application can also be implemented in other embodiments without these specific details.

[0023] It should be understood that, when used in this specification, the term "comprising" indicates the presence of the described feature, integral, step, operation, element, and / or component, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof. The terms "comprising," "including," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0024] The terms "one embodiment" or "some embodiments" used in this application mean that one or more embodiments of this application include the specific features, structures, or characteristics described in that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this application do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized.

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Please see Figure 5 The diagram shows a flowchart of a multi-mode automatic gear shifting control method for a loader in a specific embodiment. The method includes: S1. Start the loader and switch the shift mode to automatic mode to provide the basic operating state for subsequent automatic shift control.

[0027] In some embodiments, after starting the loader, the driver switches the loader's shift mode from manual to automatic using the shift mode switch on the instrument panel. During the switching process, the internal contacts of the shift mode switch close, generating a high-level automatic transmission trigger signal, which is quickly sent to the transmission control unit (TCU) via the CAN bus.

[0028] Furthermore, after receiving the signal, the TCU activates the internal automatic shift control module, performs an initial self-test on the module, and confirms that the automatic shift-related circuits, sensors, and actuators are all fault-free and the signals are normal. Then, it switches the loader's shift control system to automatic control mode, keeps the gearbox in neutral standby, and provides a stable basic operating state for all automatic shift control processes.

[0029] S2. Select the target shift mode through the mode switching module. The mode switching module includes a mode switching switch and a mode display unit. The mode display unit displays the currently selected target shift mode in real time. The target shift mode includes loading mode, transfer mode or comprehensive mode.

[0030] In some embodiments, the mode switching module consists of a mode switching switch located in the instrument panel and a mode display unit located in the middle of the vehicle's instrument cluster. The driver enters the secondary menu through the function buttons on the instrument panel, finds the shift mode selection interface, and manually clicks to select the target shift mode. The selectable modes are loading mode, transfer mode, or comprehensive mode. After selection, the mode switching switch sends the corresponding mode's encoded signal, which is transmitted to the TCU via the CAN bus. At the same time, the mode display unit synchronously updates and displays the currently selected target shift mode identifier, allowing the driver to view the current mode status in real time.

[0031] The execution method for the shovel loading mode can be as follows: S211: Based on the pre-stored engine external characteristic curve and torque converter characteristic curve data, calculate and determine the traction force-vehicle speed relationship corresponding to each gear at the current throttle opening.

[0032] In some embodiments, instead of directly storing the traction curves for all possible throttle openings, the underlying model parameters that constitute these curves are stored, including the engine external characteristic curves and the original characteristic parameters of the torque converter.

[0033] Furthermore, after the transmission electronic control unit enters the loading mode and obtains the current throttle opening signal, it determines the effective output torque curve of the engine at that throttle opening. Combining the speed ratio-torque ratio characteristics of the torque converter, it calculates the turbine torque transmitted to the input end of the transmission. Based on the transmission ratio and driving resistance characteristics of each gear, it finally obtains the curve of traction force changing with vehicle speed at that gear.

[0034] S212: The transmission electronic control unit compares the traction force-vehicle speed relationship curves of each adjacent gear at the current throttle opening, and sets the vehicle speed value corresponding to the intersection of the two curves as the preset shift point speed for switching between the two gears at the current throttle opening.

[0035] In some embodiments, after obtaining the traction-vehicle speed curves of two adjacent gears, such as F1 and F2, at the same throttle opening, the transmission control unit logically compares the values ​​of these two curves.

[0036] Because lower gears have greater traction but a lower speed range, while higher gears have less traction but a higher speed range, the two curves will inevitably intersect at some point.

[0037] The transmission electronic control unit uses an interpolation algorithm to calculate the x-coordinate value corresponding to this intersection point, i.e., the vehicle speed.

[0038] Below this speed, lower gears provide greater traction, so they should be used. Above this speed, although higher gears provide less absolute traction, they are sufficient for driving needs and allow for higher operating speeds, so higher gears should be used.

[0039] Here, we can look up and interpolate pre-discrete and stored curve data tables. At the current throttle opening, the traction force in F1 gear at vehicle speed V1 is FA, and the traction force in F2 gear at vehicle speed V2 is FB. By finding the vehicle speed point where the traction force of F1 gear equals the traction force of F2 gear, the shift point is determined.

[0040] S213: The transmission electronic control unit will collect and calculate the current actual speed of the loader in real time and compare it with the preset shift point speed corresponding to the current throttle opening determined in step S212.

[0041] In some embodiments, the preset shift point is a target value, while the actual vehicle speed is a measured value that changes instantaneously. The transmission control unit obtains pulse signals from the output shaft speed sensor and calculates the current vehicle speed using a fixed conversion factor.

[0042] Furthermore, this real-time calculated vehicle speed is compared at fixed intervals with the preset shift point vehicle speed determined in step S212, which corresponds to the current throttle opening.

[0043] In this embodiment, the comparator inside the transmission control unit outputs a Boolean logic signal: true if the actual vehicle speed is greater than the preset upshift point, or true if the actual vehicle speed is less than the preset downshift point. This comparison process is continuously executed, providing real-time input for the final shift decision.

[0044] S214: The transmission control unit determines that if the actual vehicle speed continues to exceed the preset upshift point speed within the set delay, it generates and executes an upshift command. If the actual vehicle speed remains below the preset downshift point speed within the set delay, a downshift command will be generated and executed.

[0045] In some embodiments, the transmission control unit monitors the comparison result status generated in step S213.

[0046] For upshifting conditions, the upshifting condition is only confirmed when the actual vehicle speed is greater than the preset upshifting point and this state is maintained for a preset period of time.

[0047] After confirmation, the transmission control unit sends a clear electrical signal command to the transmission hydraulic valve group, instructing it to execute a switching sequence from the current gear to the next higher gear.

[0048] Furthermore, the downshifting logic is similar, but in the opposite direction, and the downshifting delay and vehicle speed lag range can differ from upshifting to prevent frequent upshifts and downshifts due to minor road surface fluctuations. Gear shifting only occurs when the vehicle's driving state has stably crossed the preset shift boundaries, resulting in a smoother and more predictable driving experience.

[0049] As one of the execution steps of the transition mode in this application, it specifically includes the following: S221: Based on the pre-stored engine external characteristic curve and torque converter characteristic curve data, calculate and determine the torque converter efficiency-vehicle speed relationship for each gear at the current throttle opening.

[0050] In some embodiments, calculations are performed based on stored engine and torque converter basic model parameters. The calculation process is as follows: determine the engine operating point based on the current throttle opening, and combine this with the torque converter speed ratio to obtain the torque converter efficiency value under that operating condition by looking up a table or calculation.

[0051] Furthermore, torque converter efficiency characterizes the completeness of engine power transmission to the turbine shaft and is a key indicator for measuring fuel economy. For each gear, combined with its gear ratio, the torque converter efficiency of the entire transmission chain at different vehicle speeds can be calculated, thus forming the torque converter efficiency-vehicle speed curve for each gear.

[0052] S222: Compare the torque converter efficiency-vehicle speed relationship curves of each adjacent gear at the current throttle opening, and set the vehicle speed value corresponding to the intersection of the two curves as the preset shift point speed for switching between the two gears at the current throttle opening.

[0053] In some embodiments, similar to the loading mode, the efficiency-speed curves of two adjacent gears at the current throttle opening are compared, and these two curves intersect at a point. At this intersection speed, the transmission efficiency provided by the lower gear and the higher gear is equal.

[0054] Furthermore, below this speed, using a lower gear is more efficient; above this speed, shifting into a higher gear yields higher overall efficiency. This intersection speed is determined numerically and set as the preset optimal shift point for economy when switching between these two gears at this throttle opening. The goal is to ensure the vehicle operates in the most efficient gear possible at any speed.

[0055] S223: Compare the current actual speed of the loader, which is collected and calculated in real time, with the preset shift point speed corresponding to the current throttle opening, determined in step S222.

[0056] S224: If the actual vehicle speed continuously exceeds the preset upshift point speed within the set delay, an upshift command is executed; if the actual vehicle speed continuously falls below the preset downshift point speed within the set delay, a downshift command is executed.

[0057] In some embodiments, S223 compares the real-time vehicle speed with a preset efficiency shift point at the current throttle opening. S224 then triggers an upshift / downshift operation to improve fuel economy after the comparison result continues to meet a certain time condition.

[0058] As one of the execution steps of the integration mode in this application, it specifically includes the following: S231: Obtain the real-time percentage value of the throttle opening through the throttle position sensor.

[0059] In some embodiments, a voltage signal is continuously read from the accelerator pedal module. The voltage signal is calibrated and linearized, and then converted into an opening percentage value between 0% and 100%.

[0060] It's important to note that this value is either continuous or updated discretely with high resolution. In integrated mode, this real-time throttle opening value is no longer merely an index for querying a fixed shift curve, but becomes the primary key parameter determining which underlying logic to use. The transmission control unit needs to frequently sample and confirm this value because the driver's intentions change rapidly through throttle input.

[0061] S232: Determine the range to which the real-time throttle opening value belongs: If the opening is ≤ A%, proceed to step S221 and execute according to the transfer mode logic; if the opening is ≥ B%, proceed to step S211 and execute according to the loading mode logic.

[0062] In some embodiments, the transmission control unit compares the real-time throttle opening value obtained in step S231 with two preset, calibrated threshold values.

[0063] It should be noted that this comparison results in a three-way decision: if the opening degree is less than or equal to A%, the system process will completely jump to the shift decision logic of the transition mode, that is, execution will start from step S221.

[0064] If the opening is greater than or equal to B%, the system process will completely jump to the shift decision logic of the loading mode, that is, it will start from step S211.

[0065] Furthermore, the system will only enter the S233 calculation process when the opening degree is between A% and B%. These two thresholds divide the system into three distinct control regions.

[0066] S233: If the throttle opening value is between A% and B%, then the preset shift point speed calculated under that throttle opening will be called in both the loading mode and the transfer mode respectively.

[0067] According to the formula: Comprehensive shift point speed = Shift point speed in transfer mode × [1 - (current opening - A%) / (B% - A%)] + Shift point speed in loading mode × [(current opening - A%) / (B% - A%)], the dynamic shift point speed under the current throttle opening can be calculated.

[0068] In some embodiments, the driver's intent may be ambiguous or rapidly changing, such as in mixed conditions like light-load loading or transferring to uneven terrain. The system does not select a loading or transfer logic but instead performs a dynamic fusion. Two baseline values ​​need to be acquired in parallel: the optimal shift point speed for traction at the current throttle opening, denoted as Vp, is obtained by calling the loading mode.

[0069] Furthermore, the optimal shift point speed for the same throttle opening is determined by calling the transition mode logic, denoted as Ve. Vp is less than Ve, considering that the power delivery tends to downshift earlier and upshift later to maintain high torque.

[0070] The system assigns a weighting coefficient α based on the relative position of the current throttle opening within the interval [A%, B%]. Optionally, the linear mapping is: α = (current opening - A%) / (B% - A%). Thus, when the opening is close to A%, α approaches 0; when the opening is close to B%, α approaches 1.

[0071] The final shift point speed Vblend after merging is calculated using the formula Vblend=Ve×(1-α)+Vp×α. This formula allows the shift point to smoothly transition from a purely economy-oriented Ve to a purely power-oriented Vp.

[0072] The characteristic of continuous change with throttle here makes the loader's response very linear and meets the usage requirements, improving the smoothness of operation and the tacit understanding between man and machine.

[0073] S234: Compare the real-time collected actual vehicle speed with the dynamic shift point vehicle speed finally determined in step S232 or S233, and execute the corresponding upshift / downshift command according to the comparison result after the delay condition is met.

[0074] In some embodiments, the process jumps directly from step S232 to loading S211 or transfer S221, and the reference value compared in this step is the preset shift point calculated in the corresponding pure mode. If the system has undergone calculation in step S233, then the reference value for comparison is the calculated dynamic fusion value Vblend.

[0075] Furthermore, the function of this step is to compare the real-time vehicle speed with this finally determined target shift speed, and after the same delay filtering judgment, issue a shift execution command. This ensures the stability of the commands acting on the transmission.

[0076] S3: Collect the engine speed, output shaft speed and throttle opening operation signals of the loader and send them to the transmission electronic control unit.

[0077] In some embodiments, the engine speed sensor is installed at the engine output shaft to collect engine speed pulse signals in real time. Each collected pulse corresponds to the engine output shaft rotating one tooth, and the real-time engine speed is calculated by the number of pulses per unit time.

[0078] Furthermore, an output shaft speed sensor is installed at the input end of the drive axle to collect the output shaft speed pulse signal. This speed pulse signal is used not only for subsequent vehicle speed calculation but also as a signal for vehicle speed determination. A throttle position sensor is integrated inside the throttle pedal, collecting a voltage-type throttle signal. Based on the linear correspondence between the voltage value and the throttle opening, the current throttle opening (0-100%) is determined. All signals collected by the sensors are sent to the transmission control unit (TCU).

[0079] S4. The transmission electronic control unit calls the pre-stored shift parameter curve corresponding to the target shift mode selected in step S2.

[0080] S4 specifically includes the following steps: S41: Receive and lock the command signal issued by the mode selection interface, which corresponds to one of the loading mode, transfer mode or combined mode selected by the driver.

[0081] S42: Based on the locked mode command signal, retrieve a set of shift parameters that are pre-mapped to the corresponding mode from the memory; wherein, the set of shift parameters mapped to the shovel loading mode is based on traction force. The intersection point of the vehicle speed curve is determined, and the set of shift parameters mapped by the transition mode is based on the torque converter efficiency. Once the intersection of the vehicle speed curves is determined, the set of shift parameters mapped by the comprehensive mode includes both shift parameter curves for the loading mode and the transfer mode.

[0082] In some embodiments, the data corresponding to the shift parameter set mapped to the loading mode is written before the vehicle leaves the factory or during the calibration phase and stored in the form of a data table or curve fitting parameters. For loading mode and transfer mode, their complete shift point mapping table can be read directly. For the combined mode, two independent subsets need to be read: one set of shift parameter curves from loading mode and another set from transfer mode. These data represent the vehicle speed thresholds for recommended upshifting or downshifting between adjacent gears at different throttle openings.

[0083] S43: If the locked mode command signal corresponds to the comprehensive mode, then the two sets of shift parameter curves are dynamically calculated based on the real-time collected throttle opening value: when the throttle opening value is lower than the first threshold, the shift parameter curve of the transfer mode is used as the current valid shift parameter; when the throttle opening value is higher than the second threshold, the shift parameter curve of the loading mode is used as the current valid shift parameter; when the throttle opening value is between the first threshold and the second threshold, the vehicle speed at the shift point corresponding to the two sets of shift parameter curves is weighted and fused according to the relative position of the current throttle opening value within the two threshold intervals, according to the preset ratio, to generate the comprehensive shift parameter under the current throttle opening.

[0084] In some embodiments, for the integrated mode, a process is performed to dynamically synthesize the final shift parameters based on the real-time throttle opening. The process involves determining the range to which the real-time throttle opening belongs. The low throttle range is 0%-30%, the high throttle range is 70%-100%, or the medium throttle range is 30%-70%.

[0085] In the low or high throttle range, the basic shift parameters of the loaded transfer mode or loading mode are selected as the output.

[0086] In the middle throttle range, based on the current throttle opening of 50%, which is exactly the midpoint between 30% and 70%, the recommended shift speeds for loading mode and transfer mode at the same throttle opening can be weighted and averaged with a weight of 50%:50%. The result is then used as the actual shift point at the current 50% throttle opening.

[0087] Optionally, in the intermediate range, a proportionality coefficient K is obtained by calculating (current throttle opening - low threshold) / (high threshold - low threshold), where 0 < K < K. <K<1。

[0088] The final shift speed is calculated using the formula: Final shift speed = Shift speed in transfer mode * (1-K) + Shift speed in loading mode * K, to dynamically synthesize a new shift point.

[0089] In this way, when the driver lightly presses the accelerator to change positions, the system provides economy-oriented gear shifts. When the driver presses the accelerator heavily to dig, the system provides power-oriented gear shifts. In the intermediate state where the accelerator pressure varies, the system strikes a compromise between the two. This improves the ease of operation and adaptability to different working conditions.

[0090] S5. The transmission electronic control unit determines whether the conditions for upshifting or downshifting have been met based on the shift parameter curve called in step S4 and the output shaft speed signal and throttle opening signal collected in step S3.

[0091] S6. If step S5 determines that the conditions for shifting gears have been met, the transmission electronic control unit controls the hydraulic actuator to perform the shifting action. The hydraulic actuator includes the transmission proportional solenoid valve group and the shift clutch, and completes the shifting action by controlling the disengagement and engagement of the clutch.

[0092] S7. During operation, if it is necessary to switch the shift mode, return to step S2 to reselect the target shift mode, and repeat the process of steps S3 to S6 to perform automatic shift control based on the new target shift mode.

[0093] S7 specifically includes the following steps: S71: During operation, the driver returns the gear shift lever to the center to make the gear signal neutral. The mode switching operation is triggered through the instrument panel's secondary menu. The transmission control unit simultaneously receives the neutral signal from the gear shift lever and the new mode selection signal sent by the instrument panel. After continuously confirming the two signals, it marks the mode switching trigger state.

[0094] S72: The transmission electronic control unit detects whether the loader is currently in the process of shifting gears. By reading the oil pressure feedback signal and clutch engagement status signal from the hydraulic actuator module, it determines whether there is an incomplete shift action. If so, mode switching is prohibited until the shift action is completed. If it does not exist, generate a mode switching permission signal.

[0095] In some embodiments, during the upshifting and downshifting process, the clutch is in a dynamic state of disengagement or engagement, and the gears inside the transmission are in the process of meshing and switching. At this time, the switching mode will cause the TCU to output control signals of the original mode and the new mode at the same time, the solenoid valve will act erratically, the clutch will not be able to complete the engagement or disengagement normally, and the transmission will cause failures such as jamming and gear wear.

[0096] Furthermore, by using the oil pressure feedback signal and the engagement status signal, it is possible to accurately determine whether the gear shifting action has been completed. Only when the gear shifting action is stationary can the uniqueness and stability of the control signal during mode switching be ensured, which conforms to the action logic of the hydraulic actuator module.

[0097] S73: After receiving the switching permission signal, the transmission electronic control unit resets all associated parameters of the original target shift mode, including the pre-retrieved shift parameter curve, PWM control signal duty cycle, upshift / downshift timer, hysteresis adjustment parameters and shift status flag, and also resets the transmission proportional solenoid valve group to the standby opening.

[0098] In some embodiments, after receiving the mode switching permission signal, the TCU initiates the original mode parameter reset process, clearing and resetting all associated parameters one by one.

[0099] Furthermore, clear the upshift / downshift timer, mode switching timer, and oil pressure adjustment counter to zero, and reset the PWM control signal duty cycle to the standby value of 30% to ensure the solenoid valve is in the initial standby state. Next, clear the hysteresis adjustment parameters and shift status flags (upshift pending / downshift pending), and reset the oil pressure adjustment threshold to the initial calibration value.

[0100] Furthermore, a reset signal is sent to the transmission proportional solenoid valve group to control all solenoid valve openings to reset to the 5% standby opening, draining residual hydraulic oil from the clutch and ensuring that clutch action is free of residual interference when the new mode is executed. This requires eliminating the need for manual driver intervention in the reset process, improving the TCU's speed in retrieving and calculating new mode parameters, ensuring the accuracy of subsequent gear shifts, and enhancing the stability of mode switching.

[0101] S74: The driver confirms the new target shift mode through the instrument panel's secondary menu. The mode display unit updates and displays the new mode identifier simultaneously. The TCU retrieves the shift parameter curve corresponding to the new target mode and re-executes the process from steps S3 to S6. Automatic shift control is carried out based on the new mode parameters until the mode switch is triggered again or the loader stops.

[0102] In some embodiments, after the parameters are reset, the driver clicks again in the instrument panel's secondary menu to confirm the new target shift mode. The instrument panel's mode display unit updates the display of the new mode's identifier and simultaneously sends a confirmation signal to the TCU. After receiving the confirmation signal, the TCU retrieves the shift parameter curve corresponding to the new target mode. After completing the curve loading, it re-executes step S3, acquiring engine speed, output shaft speed, and throttle opening signals through the signal acquisition module and sending them to the TCU via the CAN bus.

[0103] Further, steps S4 to call the new curve, S5 to determine the upshift / downshift conditions, and S6 to execute the upshift / downshift actions are executed sequentially, and automatic shift control is carried out based on the parameters of the new target mode.

[0104] If the new mode is selected incorrectly, the driver can repeat steps S71 to S73 to reselect the target mode until the correct mode is selected and the system operates stably. Here, re-executing steps S3 to S6 ensures that the parameters of the new mode accurately match the real-time acquired sensor signals and throttle opening signals, ensuring the effectiveness of the switching process. In one embodiment of the invention, based on step S152, the following will provide a possible embodiment and its specific implementation will be described in a non-limiting manner.

[0105] In one embodiment of the present invention, based on step S5, the following is a possible embodiment and its specific implementation will be described in a non-limiting manner. S5 specifically includes the following steps: S51: Collect the current engine speed, output shaft speed and real-time throttle opening value of the loader, and parse the preset upshift point speed and preset downshift point speed corresponding to the throttle opening from the shift parameter curve called in step S4.

[0106] In some embodiments, the shift parameter curve exists in the memory of the transmission electronic control unit in the form of a discrete data table, where the row index of the table is the throttle opening and the column data is the preset shift speed corresponding to the switching between each gear.

[0107] Since the actual throttle opening value collected is continuously changing, it may not be exactly equal to the discrete index value in the data table.

[0108] For example, the current throttle opening is 47%, and the data table has two rows of data: 45% and 50%. The transmission control unit (ECU) first finds the upshift speed Vup45 corresponding to 45% and the speed Vup50 corresponding to 50%, and then calculates the preset upshift speed at 47% throttle opening using the formula Vup47 = Vup45 + (47-45) / (50-45)*(Vup50-Vup45). The same interpolation process is also applied to the calculation of the preset downshift speed. This ensures that the target value used for comparison is the latest value that precisely corresponds to the current throttle pedal position.

[0109] S52: Establish and update timers for upshifting and downshifting conditions; when the real-time vehicle speed meets the comparison condition of being greater than the preset upshifting point speed or less than the preset downshifting point speed, start or increment the corresponding timer. When the comparison condition is not met, the corresponding timer will be cleared.

[0110] In some embodiments, after the numerical comparison in step S51 is completed, the comparison result is checked. If the Boolean condition that the real-time vehicle speed > preset upshift point is true, then the upshift timer is incremented by one cycle time on the current value.

[0111] If the condition is false, the upshift timer is immediately reset to zero. The downshift timer operates in the same logic, except that the Boolean condition it listens for is changed to real-time vehicle speed < preset downshift point. Only when the accumulated value of a timer reaches a preset delay threshold is the corresponding shift condition considered to be true.

[0112] S53: Compare the real-time vehicle speed with a speed hysteresis interval obtained by expanding the vehicle speed at the preset shift point; wherein, the actual vehicle speed threshold used to trigger the downshift judgment is set to be a fixed value or a percentage lower than the preset downshift point speed, forming a downshift hysteresis.

[0113] S53 specifically includes the following steps: S531: Based on the current throttle opening value and the current gear of the loader, the corresponding downshift lag amount is parsed from the preset hysteresis parameter mapping table; the downshift lag amount represents the absolute value or percentage of the vehicle speed required to shift downward at the preset downshift point.

[0114] In some embodiments, the transmission control unit stores a two-dimensional data table. The row index of this table is the throttle opening, specifically involving 0%, 10%, ..., 100%. The column index is the gear, specifically involving F1, F2, F3, F4. The data in the table corresponds to the downshift lag amount at that throttle position and gear.

[0115] If the current throttle opening is 52% and the current gear is F3, but the data table only defines 50% and 60%, then the transmission control unit will perform linear interpolation on the two lag values ​​corresponding to 50% throttle / F3 and 60% throttle / F3, and finally calculate a specific lag value applicable to the current 52% throttle and F3 gear.

[0116] S532: Based on the preset downshift point speed calculated in step S51 and the downshift lag determined in step S531, calculate the trigger threshold speed for actual downshift judgment; use the preset upshift point speed as the trigger threshold for upshift judgment.

[0117] In some embodiments, the downshift trigger threshold Vdo is calculated using the formula: Vdo = Vdow - ΔV. Here, Vdow is the preset downshift point speed calculated in step S51, and ΔV is the hysteresis amount determined in step S531.

[0118] For the upshift trigger threshold Vup, the preset upshift point vehicle speed Vupca calculated in step S51 is used, i.e., Vup = Vupca. These two thresholds, Vup and Vdo, define a safe threshold for vehicle speed.

[0119] S533: Compare the real-time collected vehicle speed signal with the vehicle speed hysteresis window formed by the upshift trigger threshold and downshift trigger threshold determined in step S532 in real time; according to the comparison result and the current gear state, output a gear logic signal requesting an upshift, requesting a downshift, or maintaining the current gear.

[0120] In some embodiments, in each control cycle, the program reads the latest real-time vehicle speed Vactual, and compares the real-time vehicle speed Vactual with Vup and Vdo twice. The result of the comparison generates an intermediate status code. The specific rules are usually as follows: If Vactual > Vup, set the potential upshift flag.

[0121] If Vactual < Vdo, set the potential downshift flag.

[0122] If Vdo ≤ Vactual ≤ Vup, clear the above two flags, indicating that the vehicle speed is in the stable zone.

[0123] Exemplarily, when the vehicle is already in the highest gear F4, even if the vehicle speed is much higher than Vup, no potential upshift signal will be generated because there is no gear to upshift to. In the lowest gear F1, no potential downshift signal will be generated, which can effectively prevent the disturbance of the vehicle speed signal caused by various reasons.

[0124] S54: Determine that the upshift / downshift condition is met if and only if the real-time vehicle speed continuously stays outside the hysteresis interval defined in step S53 and the cumulative time of the corresponding timer in step S52 reaches the preset stable delay threshold.

[0125] S54 specifically includes the following steps: S541. The transmission electronic control unit reads the current Boolean states of the upshift override flag and downshift override flag updated in step S533 in each control cycle, and synchronously obtains the current cumulative time values of the upshift delay timer and downshift delay timer configured in step S52.

[0126] In some embodiments, the upshift override flag and downshift override flag are pre-stored. These two flags are set by step S533 based on the comparison of the real-time vehicle speed with the dynamic hysteresis threshold, and are instantaneous signals representing whether the spatial position condition is achieved.

[0127] Furthermore, the TCU reads the current values of two independently running timers. These two timers are driven to count or reset according to the same override flag in step S52.

[0128] For example, when the upshift overshoot flag is true, the upshift delay timer increments by 10 in each control cycle. When the flag is false, the timer is reset to 0. The downshift delay timer operates in a completely symmetrical manner. Step S541 in this embodiment involves capturing the states of two Boolean flags and the integer values ​​of two timers at the same time as the logical judgment.

[0129] S542, the transmission control unit compares the accumulated time of the upshift and downshift delay timers obtained in S541 with a preset stable delay threshold Tst stored in the transmission control unit. If the accumulated time of a certain timer is greater than or equal to Tst, the timeout flag corresponding to that timer is determined to be true; otherwise, it is false.

[0130] S543. The transmission electronic control unit executes the following method: if the upshift overrun flag is true and the upshift timeout flag is true, then it is determined that the upshift condition is met, and an upshift execution command with the target gear value being the current gear value plus one is generated. If the downshift overrun flag is true and the downshift timeout flag is true, then the downshift condition is met, and a downshift execution command with the target gear being one less than the current gear value is generated. If neither of the above two conditions is met, then the shift condition is not met, and no shift command is generated.

[0131] In some embodiments, the TCU executes a shift logic table: the corresponding shift condition is finally determined only when both the exceedance flag (indicating spatial condition satisfaction) and the timeout flag (indicating time condition satisfaction) are true. This conditional AND operation ensures that the shift command is issued while simultaneously satisfying both location and time constraints. Once the condition is met, the TCU does not output an upshift or downshift command, but instead generates an execution command containing the target gear number.

[0132] For example, if the current gear is 2 (F2), and the upshift condition is met, the command TARGET-GEAR=3 is generated; if the downshift condition is met, the command TARGET-GEAR=1 is generated.

[0133] This target gear value, along with the shift request, is sent to the solenoid valve drive module. If neither condition is met, the TCU will not generate any output and will maintain the current gear state.

[0134] While generating instructions, the TCU resets the corresponding timer to prepare for the next judgment loop.

[0135] The explicit target gear command generated in step S543 of this embodiment provides a clear target for the hydraulic valves and clutches of the actuators, improving the controllability of the entire gear shifting process. The proper functioning of the gear shifting logic can be determined by monitoring the flags and commands.

[0136] In one embodiment of the present invention, based on step S6, the following is a possible embodiment and its specific implementation will be described in a non-limiting manner. S6 specifically includes the following steps: S61: The transmission electronic control unit generates a PWM control signal corresponding to the upshift / downshift direction based on the determination result of step S5. The initial value of the signal duty cycle is bound to the target shift mode in step S2, and the initial duration of the signal continuous output is set.

[0137] In some embodiments, the TCU first confirms whether the determination result of step S5 is upshifting or downshifting, and generates a PWM control signal in the corresponding direction.

[0138] In shovel loading mode, the initial duty cycle of the upshift PWM signal is set to 80%, and the downshift duty cycle is set to 75%, to meet the needs of rapid gear shifting.

[0139] In transition mode, the initial duty cycle for both upshifts and downshifts is set to 60% to accommodate smooth shifting requirements.

[0140] In the integrated mode, the initial duty cycle is adjusted according to the real-time throttle opening collected in step S3. The calculation formula is D=60+0.3×(α-30), where α is the real-time throttle opening. When α<30%, D is fixed at 60%, and when α>70%, D is fixed at 81%. The 30%-70% range is calculated in real time according to the formula.

[0141] S62: The gearbox proportional solenoid valve group receives the PWM control signal sent by the TCU. The oil inlet solenoid valve and oil outlet solenoid valve of the corresponding gear work together to adjust the oil pressure of the shift clutch at a preset rate to achieve smooth rise and fall of oil pressure.

[0142] In some embodiments, the gearbox proportional solenoid valve is an electro-hydraulic valve, and its opening degree is linearly related to the duty cycle of the input PWM signal. The larger the opening degree, the greater the flow rate of hydraulic oil.

[0143] Furthermore, the oil pressure of the shift clutch is determined by the combined oil inlet flow rate of the inlet solenoid valve and the oil outlet flow rate of the outlet solenoid valve. By controlling the opening degree of both, the oil pressure can be smoothly increased or decreased. Filtering can eliminate the influence of external interference on the solenoid valve operation, ensuring the precise operation of the solenoid valve. The oil pressure feedback signal provides a basis for TCU adjustment, forming a closed-loop control.

[0144] S63: The shift clutch completes its action according to the change of oil pressure. First, the current gear clutch is disengaged. After the oil pressure drops to the preset disengagement threshold, the target gear clutch gradually engages in a linear pressure-building manner until the working oil pressure is reached.

[0145] In some embodiments, the working state of the shift clutch is controlled by hydraulic oil pressure. When the oil pressure is lower than the disengagement threshold, the pressure between the friction plates is insufficient, and power cannot be transmitted, causing the clutch to disengage.

[0146] When the oil pressure rises to the working oil pressure, the friction plates are tightly pressed together, which can stably transmit power and engage the clutch. The linear pressure build-up method allows the engagement force of the friction plates to gradually increase, and the buffer zone setting can further absorb the shifting shock. The slope difference of different modes is to adapt to the shifting speed requirements of each mode. The loading mode engages quickly to keep up with the power, while the transfer mode engages slowly to ensure smoothness.

[0147] S64: The TCU verifies whether the shift action is completed through the output shaft speed sensor and the gear feedback signal. If the shift action is completed, the PWM control signal is reset to the initial state and the shift-related timer is cleared. If the shift action is not completed, the duty cycle of the PWM signal is adjusted and steps S62-S63 are executed again.

[0148] In some embodiments, the TCU collects signals from the output shaft speed sensor and the gear position feedback sensor in real time during the gear shifting process to verify the gear shift completion status.

[0149] The verification criteria are: the speed range corresponding to the target gear matches the current output shaft speed, and the gear feedback sensor detects that the target gear is engaged without any disengagement signal. If the above conditions are met simultaneously, the TCU determines that the gear shift is complete, resets the PWM control signal duty cycle to the initial standby value of 30%, and clears the gear shift timer and oil pressure adjustment counter to prepare for the next gear shift.

[0150] If the verification fails, i.e. the speed is mismatched, the duration is insufficient, or the gear is not engaged, the TCU will adjust the duty cycle of the PWM control signal by ±5%, increase or decrease the oil pressure, and re-control the solenoid valve group and clutch operation, repeating steps S62-S63 until the gear shift is completed, repeating a maximum of 2 times. If it is still not completed, a gear shifting abnormality prompt will be triggered, and a signal will be sent to the mode display unit.

[0151] The TCU here uses dual signal verification to accurately determine whether the shift is complete. Resetting the PWM signal and timer ensures that the next shift action is not affected by residual signals from the previous action. The multiple adjustment mechanism can cope with sudden shift anomalies and improve shift reliability.

[0152] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0153] The following are embodiments of the loader multi-mode automatic shift control system provided in this disclosure. This system and the loader multi-mode automatic shift control method of the above embodiments belong to the same inventive concept. For details not described in detail in the embodiments of the loader multi-mode automatic shift control system, please refer to the embodiments of the loader multi-mode automatic shift control method.

[0154] The system includes: a mode switching module, a mode display unit, and a transmission electronic control unit; The gear shifting module is used to start the loader and switch the gear shifting mode to automatic mode; The mode switching module selects the target shift mode. The mode switching module includes a mode switching switch and a mode display unit. The mode display unit displays the currently selected target shift mode in real time. The target shift mode includes loading mode, transfer mode or comprehensive mode; it collects the loader's operating signals and sends them to the transmission electronic control unit. The transmission electronic control unit calls the pre-stored shift parameter curve corresponding to the target shift mode; based on the called shift parameter curve and the collected operating signals, it determines whether the conditions for upshifting or downshifting have been met. If the conditions for shifting gears are met, the transmission control unit controls the hydraulic actuator to perform the shifting action; it also completes the shifting action by controlling the disengagement and engagement of the clutch. During operation, if it is necessary to switch the shift mode and reselect the target shift mode, the above process should be repeated to perform automatic shift control based on the new target shift mode.

[0155] like Figure 6 As shown, this application also provides a loader, including a display module 103, a memory 102, a processor 101, a communication module 104, and a computer system stored in the memory and capable of running on the processor 101. When the processor 101 executes the system, it implements the steps of the loader multi-mode automatic gear shifting control method.

[0156] In embodiments of the invention, the loader includes, but is not limited to, laptop computers, desktop computers, workbenches, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The loader can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the embodiments described and / or claimed herein.

[0157] In this embodiment, processor 101 can be implemented using at least one of an application-specific integrated circuit, a programmable logic device, a field-programmable gate array, a processor, a transmission control unit, a micro transmission control unit, a microprocessor, or an electronic unit designed to perform the functions described herein. In some cases, such an implementation can be implemented within a transmission control unit. For software implementation, implementations such as processes or functions can be implemented with separate software modules that allow the performance of at least one function or operation. The software code can be implemented by a software application system (or system) written in any suitable programming language, and the software code can be stored in memory and executed by the transmission control unit.

[0158] The display module 103 is used to display information input by the user or information provided to the user. The display module 103 may include a display panel, which may be configured in the form of a liquid crystal display, an organic light-emitting diode, or the like.

[0159] The memory 102 can be used to store software systems and various data. The memory 102 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0160] The communication module 104 transmits radio signals to and / or receives radio signals from at least one of a base station, an external terminal, and a server. Such radio signals may include voice call signals, video call signals, or various types of data sent and / or received according to text and / or multimedia messages.

[0161] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multi-mode automatic gear shifting control method for a loader, characterized in that the method... include: S1. Start the loader and switch the gear shift mode to automatic mode; S2. Select the target shifting mode through the mode switching module. The mode switching module includes a mode switching switch and a mode display unit. The mode display unit displays the currently selected target shifting mode in real time. The target shifting mode includes loading mode, transfer mode or comprehensive mode. S3. Collect the engine speed, output shaft speed and throttle opening operation signals of the loader and send them to the transmission electronic control unit; S4. The transmission electronic control unit calls the pre-stored shift parameter curve corresponding to the target shift mode. S5. Based on the shift parameter curve called and the signal collected in step S3, determine whether the conditions for shifting up or down are met. S6. If the conditions for shifting gears are met, the transmission electronic control unit controls the hydraulic actuator to perform the shifting action; the gear shifting action is completed by controlling the disengagement and engagement of the clutch. S7. During operation, if it is necessary to switch the shift mode, return to step S2 to reselect the target shift mode, and repeat the process of steps S3 to S6 to perform automatic shift control based on the new target shift mode.

2. The multi-mode automatic gear shifting control method for a loader according to claim 1, characterized in that, S4 specifically includes the following steps: S41: Receive and lock the command signal issued by the mode selection interface, the command signal corresponding to one of the loading mode, transfer mode or combined mode selected by the driver. S42: Based on the locked mode command signal, retrieve a set of shift parameters that are pre-mapped with the corresponding mode from the memory; Among them, the set of shift parameters mapped to the shovel loading mode is based on traction force. The intersection point of the vehicle speed curve is determined, and the set of shift parameters mapped by the transition mode is based on the torque converter efficiency. Once the intersection of the vehicle speed curves is determined, the set of shift parameters mapped by the comprehensive mode includes both the shoveling mode and the transfer mode shift parameter curves. S43: If the locked mode command signal corresponds to the integrated mode, then the two sets of shift parameter curves are dynamically calculated based on the real-time throttle opening value: When the throttle opening value is lower than the first threshold, the shift parameter curve of the transition mode is used as the current effective shift parameter; When the throttle opening value is higher than the second threshold, the shift parameter curve of the shovel loading mode is used as the current valid shift parameter. When the throttle opening value is between the first threshold and the second threshold, based on the relative position of the current throttle opening value within the two threshold intervals, the vehicle speed at the shift point corresponding to the two sets of shift parameter curves is weighted and fused according to a preset ratio to generate the comprehensive shift parameters under the current throttle opening.

3. The multi-mode automatic gear shifting control method for a loader according to claim 1, characterized in that, The execution method for the shovel loading mode can be as follows: S211: Based on the pre-stored engine external characteristic curve and torque converter characteristic curve data, calculate and determine the traction force-vehicle speed relationship corresponding to each gear at the current throttle opening; S212: The transmission electronic control unit compares the traction force-vehicle speed relationship curves of each adjacent gear under the current throttle opening, and sets the vehicle speed value corresponding to the intersection of the two curves as the preset shift point vehicle speed for switching between these two gears under the current throttle opening. S213: The transmission electronic control unit will collect and calculate the current actual speed of the loader in real time and compare it with the preset shift point speed corresponding to the current throttle opening determined in step S212. S214: The transmission control unit determines that if the actual vehicle speed continues to exceed the preset upshift point speed within the set delay, it generates and executes an upshift command. If the actual vehicle speed remains below the preset downshift point speed within the set delay, a downshift command will be generated and executed. The execution method for transition modes can be as follows: S221: Based on the pre-stored engine external characteristic curve and torque converter characteristic curve data, calculate and determine the torque converter efficiency-vehicle speed relationship for each gear at the current throttle opening. S222: Compare the torque converter efficiency-vehicle speed relationship curves of each adjacent gear at the current throttle opening, and set the vehicle speed value corresponding to the intersection of the two curves as the preset shift point vehicle speed for switching between the two gears at the current throttle opening. S223: Compare the current actual speed of the loader, which is collected and calculated in real time, with the preset shift point speed corresponding to the current throttle opening, determined in step S222. S224: If the actual vehicle speed continuously exceeds the preset upshift point speed within the set delay, an upshift command is executed; if the actual vehicle speed continuously falls below the preset downshift point speed within the set delay, a downshift command is executed. The execution method for the comprehensive mode can be as follows: S231: Obtain the real-time percentage value of the throttle opening through the throttle position sensor; S232: Determine the range to which the real-time throttle opening value belongs: If the opening is ≤ A%, then proceed to step S221 and execute according to the transition mode logic; If the opening is ≥ B%, then proceed to step S211 and execute according to the loading mode logic. S233: If the throttle opening value is between A% and B%, then the preset shift point speed calculated under that throttle opening is called in both the loading mode and the transfer mode respectively; according to the formula: Comprehensive shift point speed = Transfer mode shift point speed × [1 - (current opening - A%) / (B% - A%)] + Loading mode shift point speed × [(current opening - A%) / (B% - A%)], the dynamic shift point speed under the current throttle opening is calculated; S234: Compare the real-time collected actual vehicle speed with the finally determined shift point speed, and execute the corresponding upshift / downshift command based on the comparison result after the delay condition is met.

4. The multi-mode automatic gear shifting control method for a loader according to claim 1, characterized in that, S5 specifically includes the following steps: S51: Collect the current engine speed, output shaft speed and real-time throttle opening value of the loader, call the shift parameter curve, and analyze the preset upshift point speed and preset downshift point speed corresponding to the throttle opening. S52: Establish and update timers for upshifting and downshifting conditions; when the real-time vehicle speed meets the comparison condition of being greater than the preset upshifting point speed or less than the preset downshifting point speed, start or increment the corresponding timer. When the comparison condition is not met, the corresponding timer will be cleared. S53: Compare the real-time vehicle speed with a speed hysteresis interval obtained by expanding the vehicle speed at the preset shift point; wherein, the actual vehicle speed threshold used to trigger downshift judgment is set to be lower than the preset downshift point speed by a fixed value or a percentage, forming downshift hysteresis. S54: The shifting condition is satisfied if and only if the real-time vehicle speed is continuously outside the hysteresis range defined in step S53, and the accumulated time of the corresponding timer in step S52 reaches the preset stable delay threshold.

5. The multi-mode automatic gear shifting control method for a loader according to claim 4, characterized in that, S53 specifically includes the following steps: S531: Based on the current throttle opening value and the current gear of the loader, the corresponding downshift lag amount is parsed from the preset hysteresis parameter mapping table; S532: Based on the preset downshift point speed calculated in step S51 and the downshift lag determined in step S531, calculate the trigger threshold speed for actual downshift judgment. The preset upshift point speed is used as the trigger threshold for upshift judgment; S533: The real-time vehicle speed signal is compared in real time with the vehicle speed hysteresis window formed by the upshift trigger threshold and downshift trigger threshold determined in step S532; based on the comparison result and the current gear status, the gear logic signal is output.

6. The multi-mode automatic gear shifting control method for a loader according to claim 5, characterized in that, S54 specifically includes the following steps: S541. In each control cycle, the transmission electronic control unit reads the current status of the upshift overrun flag and downshift overrun flag updated by step S533, and obtains the current cumulative time value of the upshift delay timer and downshift delay timer configured by step S52. S542. The cumulative time of the upshift and downshift delay timers obtained in S541 is compared with a preset stable delay threshold Tst stored in the transmission electronic control unit. If the cumulative time of a certain timer is greater than or equal to Tst, the timeout flag corresponding to that timer is determined to be true; otherwise, it is false. S543. If the upshift overrun flag is true and the upshift timeout flag is true, then the overall judgment is that the upshift condition is met, and an upshift execution command with the target gear value being the current gear value plus one is generated. If the downshift overrun flag is true and the downshift timeout flag is true, then the downshift condition is met, and a downshift execution command with the target gear being one less than the current gear value is generated. If neither of the above two conditions is met, then the shift condition is not met, and no shift command is generated.

7. The multi-mode automatic gear shifting control method for a loader according to claim 1, characterized in that, S6 specifically includes the following steps: S61: The transmission electronic control unit generates a PWM control signal corresponding to the upshift / downshift direction based on the determination result of step S5. S62: The gearbox proportional solenoid valve group receives the PWM control signal sent by the gearbox electronic control unit. The oil inlet solenoid valve and oil outlet solenoid valve of the corresponding gear work together to adjust the oil pressure of the shift clutch at a preset rate to achieve smooth rise and fall of oil pressure. S63: The shift clutch completes its action according to the change of oil pressure. First, the current gear clutch is disengaged. After the oil pressure drops to the preset disengagement threshold, the target gear clutch gradually engages in a linear pressure building manner until the working oil pressure is reached. S64: The transmission electronic control unit verifies whether the shift action is completed through the output shaft speed sensor and the gear position feedback signal. If the shift action is completed, the PWM control signal is reset to the initial state and the shift-related timer is cleared. If the shift action is not completed, the duty cycle of the PWM signal is adjusted and steps S62-S63 are executed again.

8. The multi-mode automatic gear shifting control method for a loader according to claim 7, characterized in that, S7 specifically includes the following steps: S71. When the driver selects a new mode through the instrument menu while the shift lever is in the neutral position, the transmission electronic control unit enters the mode switching trigger state after continuously receiving the lever neutral signal and the new mode selection signal. S72. The transmission electronic control unit detects the oil pressure and clutch status of the hydraulic actuator module. If there is an incomplete shift action, the shift is prohibited. After the action is completed, a mode switching permission signal is generated. S73. After receiving the switching permission signal, the transmission electronic control unit resets all control parameters and status flags associated with the current shift mode and resets the proportional solenoid valve group to the standby opening. S74. The driver confirms the new target shift mode through the instrument panel. The transmission electronic control unit calls the corresponding shift parameter curve and restarts the automatic shift control process based on the new parameters.

9. A multi-mode automatic gear shifting control system for a loader, characterized in that, The system is used to implement the multi-mode automatic gear shifting control method for loaders as described in any one of claims 1 to 8; The system includes: a mode switching module, a mode display unit, and a transmission electronic control unit; The gear shifting module is used to start the loader and switch the gear shifting mode to automatic mode; The mode switching module selects the target shift mode. The mode switching module includes a mode switching switch and a mode display unit. The mode display unit displays the currently selected target shift mode in real time. The target shift mode includes loading mode, transfer mode or comprehensive mode; it collects the loader's operating signals and sends them to the transmission electronic control unit. The transmission electronic control unit calls the pre-stored shift parameter curve corresponding to the target shift mode; based on the called shift parameter curve and the collected operating signals, it determines whether the conditions for upshifting or downshifting have been met. If the conditions for shifting gears are met, the transmission control unit controls the hydraulic actuator to perform the shifting action; it also completes the shifting action by controlling the disengagement and engagement of the clutch. During operation, if it is necessary to switch the shift mode and reselect the target shift mode, the above process should be repeated to perform automatic shift control based on the new target shift mode.

10. A loader, comprising a memory, a processor, and a computer system stored in the memory and operable on the processor, characterized in that, When the processor executes the system, it implements the steps of the loader multi-mode automatic shift control method as described in any one of claims 1 to 8.

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