Gearbox clutch shift control method, device and engineering vehicle

Abstract

The embodiment of the application provides a gearbox clutch shifting control method and device and an engineering vehicle, and relates to the field of speed control. The method estimates turbo torque and a shifting type by using vehicle operation data, takes the turbo torque as a direct representation of a current work load, and quantitatively determines target drive current values required by an in-switching clutch and an out-switching clutch. Then, the execution order of each shifting stage is determined according to the shifting type, so that the control logic can adapt to the power flow characteristics under different working conditions, and then in each shifting stage, the current load is adapted by combining the current actual current value, the target drive current value and the shifting type to generate a current adjustment value in real time, so as to implement differentiated current regulation and control on the clutch solenoid valve, and finally realize the controllable whole process, continuous power transmission and no jerk in the shifting process, and significantly improve the shifting smoothness, system reliability and work continuity of the engineering machinery under complex load working conditions.

Description

Technical Field

[0001] This invention relates to the field of transmission control, and more specifically, to a method, apparatus, and engineering vehicle for controlling gearbox clutch shifting. Background Technology

[0002] Electronically controlled fixed-shaft transmissions are core components of various heavy and super-heavy engineering vehicles. The smoothness of gear shifting is mainly related to the vehicle's rate of acceleration change. When the engagement and disengagement clutches are not properly coordinated, the output shaft acceleration will fluctuate significantly at synchronous speed, causing a jolt. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a gearbox clutch shifting control method, device and engineering vehicle, which can improve the shifting smoothness, system reliability and operation continuity of engineering machinery under complex load conditions.

[0004] To achieve the above objectives, the technical solutions adopted in the embodiments of the present invention are as follows: In a first aspect, the present invention provides a method for controlling gearbox clutch shifting, the method comprising: In response to shift control commands, the turbine torque and shift type are determined based on vehicle operating data; the turbine torque is used to characterize the current operating load. The execution order of each shift stage is determined according to the shift type; The input drive current value and the output drive current value are determined based on the turbine torque. During gear shifting, the current adjustment amount for the current shifting stage is determined based on the shifting type, the shift-in drive current value, the shift-out drive current value, and the shifting current value for the current shifting stage. The shift current value of the current shifting stage is updated according to the current adjustment amount. The shifting operation of the current shifting stage is controlled by the updated shift current value. The next shifting stage is entered according to the execution order until the shifting operation of the last shifting stage is completed.

[0005] In an optional implementation, determining the execution order of each shift stage according to the shift type includes: If the shift type is a powered upshift or a powerless downshift, the execution sequence of each shift stage is set as the pre-filling stage, torque exchange stage, speed exchange stage, and rapid boost stage. The shifting type is either a non-powered upshift or a powered downshift, and the execution sequence of each shifting stage is set as the pre-filling stage, speed exchange stage, torque exchange stage, and rapid boost stage.

[0006] In an optional implementation, the current adjustment amount includes an increase in shift-in and a decrease in shift-out, and the shift current value includes a shift-out current value and a shift-in current value; determining the current adjustment amount for the current shift stage based on the shift type, the shift-in drive current value, the shift-out drive current value, and the shift current value for the current shift stage includes: If the current shift stage is a pre-filling stage, the shift reduction amount of the current shift stage is determined based on the shift current value and the shift drive current value of the current shift stage. The shift-in increase amount for the current shift stage is determined based on the shift-in current value of the current shift stage and the preset KP current value.

[0007] In an optional implementation, the current adjustment amount includes an increase in shift-in and a decrease in shift-out; determining the current adjustment amount for the current shift stage based on the shift type, the shift-in drive current value, the shift-out drive current value, and the shift current value for the current shift stage includes: If the shift type is a powered upshift or a powerless downshift and the current shift stage is a torque exchange stage, the first current value is determined according to the preset KP current value and the first preset value. The shift reduction amount for the current shift stage is determined based on the shift drive current value and the first current value. The shift-in increase amount for the current shift stage is determined based on the preset KP current value and the shift-in drive current value.

[0008] In an optional implementation, the current adjustment amount includes a shift-in increase; determining the current adjustment amount for the current shift stage based on the shift type, the shift-in drive current value, the shift-out drive current value, and the shift current value for the current shift stage includes: If the shift type is a non-powered upshift and the current shift stage is a torque exchange stage, the second current value is determined according to the preset KP current value and the second preset value. The shift-in increase amount for the current shift phase is determined based on the second current value and the shift-in drive current value.

[0009] In an optional implementation, the current adjustment amount includes an increase in shift-in and a decrease in shift-out, and the shift current value includes a shift-out current value; determining the current adjustment amount for the current shift stage based on the shift type, the shift-in drive current value, the shift-out drive current value, and the shift current value for the current shift stage includes: If the shift type is a powered downshift and the current shift stage is a torque exchange stage, the first current value and the second current value are determined according to the preset KP current value, the first preset value and the second preset value. The amount of reduction in shifting speed during the current shifting stage is determined based on the shifting current value during the current shifting stage and the first current value. The shift-in increase amount for the current shift phase is determined based on the second current value and the shift-in drive current value.

[0010] In an optional implementation, the current adjustment amount includes an increase in shift-in and a decrease in shift-out; determining the current adjustment amount for the current shift stage based on the shift type, the shift-in drive current value, the shift-out drive current value, and the shift current value for the current shift stage includes: If the shift type is a powered upshift or a powerless downshift and the current shift stage is a speed exchange stage, the first current value is determined according to the preset KP current value and the first preset value. The shift reduction amount for the current shift stage is determined based on the first current value and the third preset value. The shift-in increment for the current shift stage is determined based on the target turbine speed, output shaft speed, gear ratio of the engaged gear, actual turbine speed, and gear ratio of the disengaged gear.

[0011] In an optional implementation, the current adjustment amount includes an increase in shift-in and a decrease in shift-out; determining the current adjustment amount for the current shift stage based on the shift type, the shift-in drive current value, the shift-out drive current value, and the shift current value for the current shift stage includes: If the shift type is a non-powered upshift or a powered downshift and the current shift stage is a speed exchange stage, the second current value is determined according to the preset KP current value and the second preset value. The reduction amount of the shift-out gear in the current shift stage is determined based on the target turbine speed, output shaft speed, gear ratio of the engaged gear, actual turbine speed, and gear ratio of the disengaged gear. The shift-in increment for the current shift stage is determined based on the preset KP current value and the second current value.

[0012] In a second aspect, the present invention provides a gearbox clutch shifting control device, the device comprising: A preprocessing module is used to respond to shift control commands, determine the turbine torque and shift type based on vehicle operating data; the turbine torque is used to characterize the current operating load; and determine the execution sequence of each shift stage based on the shift type. The processing module is used to determine the shift-in drive current value and the shift-out drive current value based on the turbine torque; during the shifting process, it determines the current adjustment amount of the current shifting stage based on the shifting type, the shift-in drive current value, the shift-out drive current value, and the shifting current value of the current shifting stage. The processing module is also configured to update the shift current value of the current shifting stage according to the current adjustment amount, control the shifting operation of the current shifting stage using the updated shifting current value, and enter the next shifting stage according to the execution order until the shifting operation of the last shifting stage is completed.

[0013] Thirdly, the present invention provides an engineering vehicle including a gearbox and a controller, wherein the controller can execute a computer program to control the gearbox to implement the gearbox clutch shifting control method described in any of the foregoing embodiments.

[0014] Compared to existing technologies, the transmission clutch shifting control method, device, and engineering vehicle provided in this invention utilize vehicle operating data to estimate turbine torque and shift type, and uses turbine torque as a direct representation of the current operating load to quantitatively determine the target drive current values ​​required for each shift-in and shift-out clutch. Then, based on the shift type, the execution sequence of each shift stage is determined, enabling the control logic to adapt to the power flow characteristics under different operating conditions. Furthermore, in each shift stage, the current adjustment amount adapted to the current load is generated in real time by combining the current actual current value, target drive current value, and shift type, thereby implementing differentiated current control of the clutch solenoid valve. Under high load, the rate of current change is slowed to avoid power interruption or shock; under low load, the current response is accelerated to shorten shifting time. Ultimately, the entire shifting process is controllable, power is continuously transmitted, and there is no jerking, significantly improving the shifting smoothness, system reliability, and operational continuity of engineering machinery under complex load conditions.

[0015] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic flowchart of a gearbox clutch shifting control method provided in an embodiment of the present invention is shown.

[0018] Figure 2 A schematic diagram of the power transmission of an engineering vehicle is shown.

[0019] Figure 3 This diagram illustrates a clutch pressure control curve for powered upshifting provided in an embodiment of the present invention.

[0020] Figure 4 This diagram illustrates a clutch pressure control curve for unpowered upshifting provided by an embodiment of the present invention.

[0021] Figure 5 This diagram illustrates a clutch pressure control curve for powered downshifting provided in an embodiment of the present invention.

[0022] Figure 6 This diagram illustrates a clutch pressure control curve for powerless downshifting provided by an embodiment of the present invention.

[0023] Figure 7 A block diagram of a gearbox clutch shift control device provided in an embodiment of the present invention is shown.

[0024] Figure 8 A block diagram of an engineering vehicle provided in an embodiment of the present invention is shown. Detailed Implementation

[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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0027] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0028] First, the keywords or key terms involved in the embodiments of the present invention will be introduced: 1. Torque converter: A hydraulic transmission device located between the engine and the transmission, which uses automatic transmission fluid as a working medium to transmit and increase the torque from the engine.

[0029] 2. Gearbox: The core transmission component, which changes the gear ratio between the engine and the drive wheels to enable the vehicle to move forward, accelerate, decelerate or reverse, and match different driving conditions.

[0030] 3. Gearbox Clutch: This project uses multi-plate wet clutches, which consist of multiple friction plates. One part is connected to the input or output shaft, and the other part is connected to a specific gear. When power needs to be transmitted to a specific gear, the hydraulic system applies pressure to the clutch, causing the friction plates to come into close contact, thereby completing the power transmission.

[0031] 4. Transmission Turbine Shaft: In this project, it refers to the shaft in the automatic transmission that is connected to the torque converter turbine. A speed sensor is installed on the turbine shaft. The turbine shaft speed sensor is one of the most important input signals of the transmission control unit (TCU), which is used to calculate slip, accurately determine the shift timing, and control the smoothness of shifting.

[0032] 5. Nominal torque of the torque converter: refers to the pump wheel torque at 1000 r / min, the highest efficiency condition. It is the core calibration parameter of the hydraulic torque converter, reflecting the basic load-bearing capacity of the torque converter at standard speed.

[0033] 6. Torque converter pump wheel torque: This is the turbine torque transmitted from the engine to the torque converter pump wheel. It is the starting parameter for power transmission in the hydraulic transmission system and directly determines the upper limit of turbine torque output.

[0034] 7. Transmission turbine torque: This is the output torque of the hydraulic torque converter turbine, which is a core parameter that determines the amount of input power of the transmission and directly affects the traction and working capacity of the whole machine.

[0035] 8. Torque converter torque ratio: This is the ratio of the transmission turbine torque to the torque converter pump wheel torque. It is a core performance indicator that measures the torque amplification capability of the torque converter. The torque ratio changes with the speed ratio of the turbine to the pump wheel. When the turbine is stationary, the torque converter torque ratio reaches its maximum value, and the output torque is at its maximum.

[0036] 9. KP Point: This refers to the point where the clutch overcomes the force of the return spring and begins to press the friction plates and steel plates together. The point where the friction plates and steel plates are pressed together is called the Kiss Point, or KP Point. The current and pressure corresponding to the KP Point are called KP Current and KP Pressure.

[0037] 10. Torque Phase: The process of gradually transferring the transmission turbine torque from the disengaging clutch to the engaging clutch is called the torque phase, or torque exchange.

[0038] 11. Speed ​​phase: The process of smoothly transitioning the input shaft speed of the gearbox corresponding to the current gear ratio to the input shaft speed corresponding to the target gear ratio is called speed phase, i.e. speed exchange.

[0039] 12. Clutch torque coefficient: The ratio of the clutch-transmitted torque to the input shaft torque.

[0040] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0041] Please refer to Figure 1 , Figure 1 A schematic flowchart of a gearbox clutch shifting control method provided by an embodiment of the present invention is shown. The method includes the following steps: Step S10: In response to the shift control command, determine the turbine torque and shift type based on the vehicle operating data; the turbine torque is used to characterize the current operating load.

[0042] It should be noted that the power transmission system of construction machinery consists of an engine, torque converter, gearbox, drive shaft and drive axle, and electronic control system. The power transmission method is as follows: Figure 2 As shown, the engine provides the raw power, and its output torque and speed must be matched with the characteristics of the transmission system. The torque converter is the core of the hydraulic transmission system. It is connected to the engine and transmits power through automatic transmission fluid as the working medium, serving to regulate torque and buffer load shocks.

[0043] The gearbox is connected to the torque converter. Loaders commonly use fixed-shaft gearboxes, which change the transmission ratio by shifting gears to meet the needs of high-speed driving and low-speed heavy-load conditions, and work with the torque converter to achieve power regulation. The driveshaft is responsible for transmitting the power output from the gearbox to the drive axle. The drive axle further increases torque and reduces speed through the final drive and differential, distributing power to the left and right wheels to enable the vehicle to move.

[0044] As the brain of the transmission system, the electronic control system collects parameters such as engine speed, torque converter oil temperature, and gearbox gear position in real time. Through logic control, it determines load, issues shift commands, and executes shift actions. This invention optimizes the electronic control system's control strategy and algorithm to achieve clutch control under different loads.

[0045] Is the torque exchange during gear shifts equivalent to the transmission's turbo torque or equivalent to the output torque?

[0046] If torque is transmitted using the same transmission turbine torque, the output torque of the transmission will change due to the change in the gear ratio during the torque phase. With the same transmission turbine torque, the output torque decreases during upshifting and increases during downshifting. In an electronically controlled fixed-shaft transmission, the clutch torque coefficients of the engagement and disengagement clutches are not the same. Therefore, the torque rise slope of the engagement clutch differs from the torque fall slope of the disengagement clutch. Torque exchange control curves need to be fitted separately to ensure that the total transmitted transmission turbine torque remains constant.

[0047] Theoretically, if torque transmission were based on the same torque as the transmission output shaft, the vehicle acceleration before and after a gear shift could remain constant, further improving shift quality. However, in practical applications, to ensure constant output torque after a gear shift, the turbine torque needs to be adjusted synchronously after the clutch shifts. This requires real-time increases and decreases in engine torque, meaning that engine throttle control must use a throttle opening map based on the transmission output shaft torque, rather than the currently widely used map based on engine torque or power. This method requires a higher level of integrated engine and transmission control, which is complex to implement and not conducive to practical application. Therefore, current transmission torque transmission during gear shifts is still based on the principle of using the same torque as the transmission turbine.

[0048] In this embodiment of the invention, the transmission can be an electronically controlled fixed-shaft transmission with six clutches. The six clutches work together to form four forward gears and three reverse gears. Each gear requires the engagement of two clutches to drive the vehicle. The engagement and disengagement of the transmission clutches are achieved by the TCU output current controlling the proportional solenoid valve.

[0049] In practical applications, firstly, in response to the shift control command issued by the driver or the controller of the engineering vehicle, the vehicle operation data such as engine speed, pump wheel speed, turbine speed, and throttle opening are randomly collected, and the turbine torque and shift type are determined based on the vehicle operation data.

[0050] Turbo torque of the transmission The calculation formula is:

[0051] in, It is the torque converter torque ratio. The torque converter's nominal torque is the core calibration parameter of the torque converter, which is the torque converter's torque ratio. It refers to the pump impeller speed.

[0052] One possible implementation is to determine the shift type based on engine speed, throttle opening, and transmission input shaft speed. The shift type reflects the power output of the engine on the load. If it promotes load acceleration, it's a powered shift; if it inhibits load acceleration, it's a non-powered shift. The steps to determine the shift type may include: First, if the throttle opening exceeds the opening threshold or the transmission input shaft speed is less than the engine speed, and the outgoing gear is less than the incoming gear, the engine will promote the load at the rear end, and the upshift will be a powered upshift. In this case, the shift type will be set to powered upshift.

[0053] Second, if the throttle opening does not exceed the opening threshold or the transmission input shaft speed is greater than the engine speed, and the outgoing gear is less than the incoming gear, such as when the throttle is suddenly released from a large position or during a long downhill driving condition, the load at the rear is dragging the engine, and the engine power has an inhibitory effect on the acceleration of the load. In this case, the upshift is a non-powered upshift, and the shift type is set to non-powered upshift.

[0054] Third, if the throttle opening exceeds the opening threshold or the ratio of the transmission input shaft speed to the engine speed is less than the preset ratio (e.g., 0.6), and the outgoing gear is greater than the incoming gear, the engine power will promote the acceleration of the load at the rear end, and the downshift will be a powered downshift. In this case, the shift type will be set to powered downshift.

[0055] Fourth, if the throttle opening does not exceed the opening threshold or the braking signal is active, and the outgoing gear is greater than the incoming gear, for example, releasing the throttle to allow the vehicle to coast and decelerate or brake to decelerate (such as pressing the brake to set the braking signal to 1, i.e., the braking signal is active; releasing the brake to set the braking signal to 0, i.e., the braking signal is inactive), then the engine power will suppress the acceleration of the load, and the downshift will be a non-powered downshift. In this case, the shift type will be set to non-powered downshift.

[0056] Step S20: Determine the execution order of each shift stage according to the shift type.

[0057] In this embodiment of the invention, the execution order of the shifting stage is adjusted according to the power characteristics of the shifting type. This order adjustment is to match the actual needs of whether the power flow is interrupted or not, and whether speed synchronization or torque transmission takes priority during different shifting processes.

[0058] Step S30: Determine the input drive current value and the output drive current value based on the turbine torque.

[0059] Next, the clutch torque is determined based on the turbo torque of the transmission. The calculation formula is:

[0060] in, This is the clutch torque coefficient. Table 1 provides an example of the possible values ​​for the clutch torque coefficient.

[0061] Table 1

[0062] The clutch control process consists of two steps: First, the required oil pressure (i.e., drive pressure value) is calculated based on the clutch torque. This step depends on the mechanical structure parameters of the transmission. Next, the required oil pressure is converted into a drive current value. This step depends on the solenoid valve PC function (i.e., pressure-current function) of the transmission's hydraulic system.

[0063] The formula for calculating the driving pressure value P is:

[0064] in, It is the number of steel plates in the clutch; It is the radius of the clutch friction plate; It is the coefficient of kinetic friction; It is the area of ​​the clutch piston chamber; It is the clutch pressure at point KP.

[0065] The engagement drive voltage is determined based on the engagement clutch's torque, number of steel plates, clutch friction plate radius, dynamic friction coefficient, clutch piston chamber area, and pressure at point KP. Similarly, the disengagement drive voltage is determined based on the disengagement clutch's torque, number of steel plates, clutch friction plate radius, dynamic friction coefficient, clutch piston chamber area, and pressure at point KP.

[0066] Next, based on the pressure-current function corresponding to the switching clutch (e.g.) ), to calculate the engagement drive current value of the engagement clutch. Similarly, based on the pressure-current function corresponding to the disengagement clutch (e.g., ), and calculate the disengagement drive current value of the disengagement clutch.

[0067] Step S40: During the gear shifting process, determine the current adjustment amount for the current shifting stage based on the shifting type, the shift-in drive current value, the shift-out drive current value, and the shifting current value of the current shifting stage.

[0068] When each shifting phase is actually executed, the execution time of the current shifting phase is obtained, and the total current adjustment corresponding to the current shifting phase is determined based on the shifting type, the shift-in drive current value, the shift-out drive current value, and the shifting current value of the current shifting phase. Then, the current adjustment amount is determined based on the total current adjustment amount and the execution time.

[0069] The current adjustment amount can be an adjustment ratio (e.g., 5%) or an adjustment value (e.g., 100), and the present invention does not limit this.

[0070] Step S50: Update the shift current value of the current shift stage according to the current adjustment amount, control the shift operation of the current shift stage using the updated shift current value, and enter the next shift stage according to the execution order until the shift operation of the last shift stage is completed.

[0071] In this embodiment of the invention, during the current shifting phase, the shifting current value is updated at a constant speed according to the current adjustment amount. The updated shifting current value drives the solenoid valve to precisely adjust the oil pressure, thereby controlling the clamping degree and slipping state of the clutch friction plate.

[0072] After completing the current shifting phase, the system proceeds to the next shifting phase according to the predetermined execution sequence until the rapid boost phase is completed, the clutch is fully locked, and the shifting is completely finished. It should be understood that the shifting current value of the next shifting phase is the same as the shifting current value at the end of the previous shifting phase.

[0073] In summary, the gearbox clutch shift control method provided by this invention estimates the turbine torque and shift type using vehicle operating data, and uses the turbine torque as a direct representation of the current operating load to quantify and determine the target drive current values ​​required for each of the engagement and disengagement clutches. Then, based on the shift type, the execution sequence of each shift stage is determined, enabling the control logic to adapt to the power flow characteristics under different operating conditions. Furthermore, in each shift stage, the current adjustment amount adapted to the current load is generated in real time by combining the current actual current value, the target drive current value, and the shift type, thereby implementing differentiated current control of the clutch solenoid valve. Under high load, the rate of current change is slowed to avoid power interruption or shock; under low load, the current response is accelerated to shorten shift time. Ultimately, the entire shift process is controllable, with continuous power transmission and no jerking, significantly improving the shift smoothness, system reliability, and operational continuity of construction machinery under complex load conditions.

[0074] Optionally, the shifting phase includes a pre-filling phase, a torque exchange phase, a speed exchange phase, and a rapid boost phase. Regarding how to determine the execution order of each shifting phase, a possible implementation method is provided below. Figure 1 The sub-steps of step S20 may include: Step S200: If the shift type is a powered upshift or a powerless downshift, the execution sequence of each shift stage is set as the pre-filling stage, torque exchange stage, speed exchange stage, and rapid boost stage.

[0075] In this embodiment of the invention, the "power shift first" or "speed adjustment first" is dynamically determined by distinguishing the shift type, thereby ensuring that the clutch action sequence truly matches the physical constraints under different operating conditions. Specifically, the entire engagement process of the transmission clutch is divided into four shift stages: pre-filling stage, torque exchange stage, speed exchange stage, and rapid pressure boosting stage.

[0076] The goal of the torque exchange phase (also known as the torque phase) is to smoothly transfer the transmission turbine torque from the disengaging clutch to the engaging clutch, ensuring uninterrupted power delivery. The goal of the speed exchange phase (also known as the speed phase) is to smoothly transition the transmission input shaft speed from the speed corresponding to the current gear to the speed required by the target gear. The order of these two phases is not fixed but depends on the type of gear shift being performed.

[0077] If the shift type is a powered upshift or a powerless downshift, it means that the clutch engaged in the shift is capable of transmitting torque. For example, when upshifting with power, the engine is still outputting positive power, the gear ratio of the engaged gear decreases, the turbocharger speed naturally decreases, and the clutch engaged in the shift is in a positive slip state; when downshifting without power, the vehicle decelerates and coasts, the gear ratio of the engaged gear increases, the clutch engaged in a negative slip state, and it can also stably transmit negative torque.

[0078] Therefore, the torque exchange stage is performed first to allow the power to transition smoothly. After the ex-clutch is completely disengaged and no longer transmits torque, the speed exchange stage is entered. At this time, it is only necessary to adjust the pressure of the input clutch so that the slip difference between the master and slave ends gradually approaches zero. This process adopts PI closed-loop control to make the input shaft speed change smoothly according to the preset curve, thus completing the speed exchange stage.

[0079] Step S210: The shift type is either a non-powered upshift or a powered downshift. The execution sequence of each shift stage is set as the pre-filling stage, speed exchange stage, torque exchange stage, and rapid boost stage.

[0080] Conversely, if the shift type is a non-powered upshift or a powered downshift, the engagement clutch is not yet capable of transmitting the required directional torque. For example, a non-powered upshift occurs when coasting with the accelerator released; the gear ratio of the engaged gear is smaller, requiring the turbocharger speed to increase to match, but the engagement clutch initially has a positive slip and cannot withstand the impending negative torque. A powered downshift often occurs when downshifting under load; the gear ratio of the engaged gear is larger, requiring a significant reduction in turbocharger speed, and the engagement clutch initially has a negative slip and cannot yet transmit positive torque.

[0081] Therefore, the speed exchange phase is performed first. Instead of switching into the engaging clutch, the pressure of the disengaged clutch is actively adjusted to allow its slip difference to change slowly, driving the input shaft speed closer to the target value. Once the slip of the engaging clutch enters the torque-transmitting range, the torque exchange phase begins, completing the power transfer.

[0082] As can be seen, the embodiments of the present invention dynamically set the execution sequence of the four stages according to the shift type, ensuring that the clutch action strictly matches the physical feasibility. When the engaged clutch has torque transmission capability (e.g., upshifting with power, downshifting without power), torque exchange is completed first, and then the speed is adjusted to avoid power interruption. When the engaged clutch does not yet have torque transmission capability (e.g., upshifting without power, downshifting with power), the pressure of the disengaged clutch is adjusted first to change the input shaft speed, so that the slip of the engaged clutch enters the torque transmission range before torque is transferred, thereby preventing slippage, impact, or engagement failure, and significantly improving the smoothness and reliability of shifting under various operating conditions.

[0083] Optionally, the current adjustment includes an increase in shift-in and a decrease in shift-out, and the shift current value includes an outward current value and a shift-in current value. Regarding how to use the shift type to determine the decrease in shift-out of the outward clutch and the increase in shift-in of the inward clutch in each shift stage, a possible implementation method is provided below. Figure 1 The sub-steps of step S40 may include: Step S400: If the current shift stage is the pre-filling stage, determine the shift reduction amount of the current shift stage based on the shift current value and the shift drive current value of the current shift stage.

[0084] In this embodiment of the invention, during the pre-charging phase, the reduction in shift current value per control cycle (e.g., every 10 milliseconds) is determined based on the difference between the shift-out current value and the shift-out drive current value in the current shift phase, and the execution time of the pre-charging phase. For example, if the shift-out current value is 1000 mA, the shift-out drive current value is 600 mA, the execution time is 200 milliseconds, the control cycle is 10 milliseconds, and current adjustment is performed every 10 milliseconds, then the reduction in shift current value per 10 milliseconds is 20. The shift-out current value is 600 mA at the end of the shift-in pulse current phase, and the initial shift-out current value for the next shift phase is 600 mA at the end of the pre-charging phase.

[0085] For example, when shifting up with power and down without power, the disengagement clutch needs to release oil to a pressure plateau slightly higher than the transmittable torque, and the corresponding current is reduced to maintain only a weak drag capability (i.e., the disengagement drive current value) to prevent the turbine shaft from rising rapidly due to sudden power unloading.

[0086] When downshifting with power and upshifting without power, the torque capacity of the disengaging clutch must be precisely reduced to the level of the actual transmitted torque. The corresponding current is reduced to the disengaging drive current value, so that there is no excess positive torque that causes impact, nor is there any residual negative torque that interferes with subsequent speed regulation.

[0087] Step S401: Determine the shift-in increase amount for the current shift stage based on the shift-in current value and the preset KP current value for the current shift stage.

[0088] Meanwhile, the increase in engagement current during the pre-charging phase is determined based on the difference between the preset KP current value (the critical current at which the clutch friction plates just make contact with the steel plates and begin to generate a small torque) and the current engagement current value, as well as the execution time of the pre-charging phase. Regardless of the shift type, the engagement clutch performs pulse charging and KP charging. That is, a short current pulse is first applied to complete the initial pressure build-up, and then stabilized near the KP current value, so that the friction plates and steel plates just lightly touch, forming an initial engagement tendency and enabling the transmission of small torque.

[0089] As can be seen, during the pre-filling stage, the amount of reduction in the shifting clutch is determined by the difference between the current shifting current value and the shifting drive current value, so that the shifting clutch can smoothly release pressure to the torque maintenance level suitable for the current working condition; at the same time, the amount of increase in the shifting clutch is determined by the difference between the current shifting in current value and the KP current value, so that the shifting in clutch can accurately build pressure to the initial contact state between the friction plate and the steel plate, thus establishing controllable and reliable physical preparatory conditions for torque or speed exchange, avoiding power interruption or engagement shock, and improving the stability and adaptability of the shifting process.

[0090] Optionally, the current adjustment includes an increase in shift-in and a decrease in shift-out. Regarding how to determine the decrease in shift-out of the shift-out clutch and the increase in shift-in of the shift-in clutch in each shift stage using the shift type, a possible implementation method is provided below. Figure 1 The sub-steps of step S40 may include: Step S410: If the shift type is a powered upshift or a powerless downshift and the current shift stage is a torque exchange stage, determine the first current value based on the preset KP current value and the first preset value.

[0091] It should be noted that the technical problem to be solved by the embodiments of the present invention is as follows: During the torque exchange phase of upshifting with power and downshifting without power, if the torque of the disengaging clutch decreases too quickly while the torque of the engaging clutch increases too slowly, the turbine shaft speed will rise rapidly, resulting in runaway. If the disengaging clutch decreases too slowly while the engaging clutch increases too quickly, the disengaging clutch cannot disengage in time, and is forced to transmit negative torque in the latter half, resulting in power backflow. The root cause of this problem is that the engaging clutch already has torque transmission capability at the beginning of torque exchange (positive slip when upshifting with power, negative slip when downshifting without power), therefore, bidirectional control must be activated synchronously.

[0092] In this embodiment of the invention, when the engineering vehicle performs a powered upshift or a powerless downshift and is currently in the torque exchange phase, a first current value is first determined based on the difference between the KP current value and a first preset value (e.g., 50). The first current value is the target reference for disengaging the clutch oil, meaning that when disengaging, oil is slowly discharged from the platform pressure (i.e., the oil pressure corresponding to the disengagement drive current value) to the oil pressure corresponding to the first current value.

[0093] Step S411: Determine the shift reduction amount for the current shift stage based on the shift drive current value and the first current value.

[0094] Subsequently, the shift reduction amount for the torque exchange phase is determined based on the difference between the shift drive current value and the first current value, as well as the execution time of the torque exchange phase. By gradually adjusting the shift current value during the torque exchange phase through the shift reduction amount, the torque capacity of the shift clutch decreases smoothly, preventing a sudden increase in turbine shaft speed (runaway) due to excessively rapid decrease, or a negative torque transmission in the latter half of the transmission due to excessively slow decrease, which could trigger power backflow.

[0095] Step S412: Determine the shift increase amount for the current shift stage based on the preset KP current value and the shift drive current value.

[0096] Meanwhile, the increase in torque exchange during the shift-in stage is determined based on the difference between the shift-in drive current and the KP current, as well as the execution time of the torque exchange stage. This causes the shift-in clutch current to gradually increase from the KP current, and the corresponding torque to increase smoothly according to the set slope. Finally, the output torque is smoothly transitioned to the shift-in gear, and the shift-out clutch is completely disengaged.

[0097] Optionally, the current adjustment includes the shift-in increase. Regarding how to determine the shift-out reduction of the shift-out clutch and the shift-in increase of the shift-in clutch in each shift phase using the shift type, a possible implementation is provided below. Figure 1 The sub-steps of step S40 may include: Step S420: If the shift type is non-powered upshift and the current shift stage is the torque exchange stage, determine the second current value based on the preset KP current value and the second preset value.

[0098] In this embodiment of the invention, non-powered upshifting refers to a situation where the accelerator is suddenly released after heavy acceleration, canceling the acceleration intention. The transmission needs to upshift as quickly as possible to reduce engine speed, decrease engine drag power, and achieve higher fuel economy. During non-powered upshifting, the negative torque of the outgoing gear needs to be smoothly transferred to the engagement clutch. The engagement gear initially has positive slip and does not yet have the ability to transmit negative torque. Therefore, in non-powered upshifting control, a speed exchange phase is executed first, and the torque exchange phase is executed only after the torque of the engagement gear changes from positive to negative.

[0099] It should be understood that the torque exchange phase during unpowered upshifting is characterized by very small slip, small torque to be transmitted, and extremely short duration. The torque exchange phase ends when the slip approaches zero. Under this constraint, the sum of the KP current value and the second preset value (e.g., 20) is determined as the second current value.

[0100] Step S421: Determine the shift-in increase amount for the current shift stage based on the second current value and the shift-in drive current value.

[0101] Next, the shift-in increment for the torque exchange phase is determined based on the difference between the shift-in drive current value and the second current value, as well as the execution time of the torque exchange phase. Assume that the shift-in increment is obtained by dividing the difference between the shift-in drive current value and the second current value by the execution time of the torque exchange phase. That is, the shift-in clutch increases the shift current value by one shift-in increment every unit of time. For example, if the shift-in increment is 10 / 10 milliseconds, the current value of the shift-in clutch is currently 600 mA, after 100 milliseconds it will be 700 mA, and after 200 milliseconds it will be 800 mA.

[0102] Optionally, the current adjustment includes an increase in shift-in and a decrease in shift-out, and the shift current value includes the shift-out current value. Regarding how to determine the decrease in shift-out of the shift-out clutch and the increase in shift-in of the shift-in clutch in each shift stage using the shift type, a possible implementation method is provided below. Figure 1 The sub-steps of step S40 may include: Step S430: If the shift type is a powered downshift and the current shift stage is a torque exchange stage, determine the first current value and the second current value according to the preset KP current value, the first preset value and the second preset value.

[0103] In this embodiment of the invention, when the shift type is a power downshift and the torque exchange stage has been entered, the difference between the KP current value and a first preset value is determined as the first current value, and the sum of the KP current value and a second preset value is determined as the second current value. The first current value is less than the second current value.

[0104] Step S431: Determine the reduction amount of the shifting current in the current shifting stage based on the shifting current value and the first current value.

[0105] Next, based on the difference between the current shift current value and the first current value during the current shift phase, and the execution time of the torque exchange phase, the shift reduction amount for the torque exchange phase is determined. The shift clutch gradually reduces its current value based on the shift reduction amount to smoothly reduce the hydraulic engagement pressure of the shift clutch and avoid sudden disengagement of the shift clutch causing power interruption.

[0106] Step S432: Determine the shift-in increase amount for the current shift stage based on the second current value and the shift-in drive current value.

[0107] Simultaneously, based on the difference between the input drive current value and the second current value, and the execution time of the torque exchange phase, the input increase during the torque exchange phase is determined. This input increase is added to the input current value of the input clutch to increase the hydraulic engagement pressure of the input clutch, enabling it to quickly assume full power output after acquiring positive torque transmission capability, thereby preventing abnormal increases in turbine shaft speed.

[0108] It should be noted that powered downshifting refers to the process where engine power is transmitted to the wheels in the forward direction through the transmission during gear shifting. In the initial stage of the shift, the disengaging clutch transmits positive torque, while the engaging clutch, due to the unmatched speeds, is in a negative slip state, meaning it has not yet entered effective engagement and lacks the ability to transmit positive torque. Therefore, the entire powered downshifting process follows a control sequence of "first completing speed matching, then executing torque transfer," that is, completing the speed exchange stage first, then entering the torque exchange stage. In the torque exchange stage, the engaging clutch already has the ability to transmit positive torque. At this point, by rapidly increasing its control oil pressure and simultaneously rapidly decreasing the control oil pressure of the disengaging clutch, both the rapid establishment of output torque and the smooth transition of the shift process can be achieved until the torque carrying capacity of the engaging clutch exceeds the actual requirement, at which point the shift operation is complete.

[0109] Optionally, the current adjustment includes an increase in shift-in and a decrease in shift-out. Regarding how to determine the decrease in shift-out of the shift-out clutch and the increase in shift-in of the shift-in clutch in each shift stage using the shift type, a possible implementation method is provided below. Figure 1 The sub-steps of step S40 may include: Step S440: If the shift type is a powered upshift or a powerless downshift and the current shift stage is a speed exchange stage, determine the first current value based on the preset KP current value and the first preset value.

[0110] Step S441: Determine the shift reduction amount for the current shift stage based on the first current value and the third preset value.

[0111] In this embodiment of the invention, when the engineering vehicle performs a powered upshift or a powerless downshift, after completing the torque exchange phase, it enters the speed exchange phase. The speed exchange phase uses a time-varying control system based on proportional-integral (PI) gain adjustment to adjust the clutch, which is simple to operate and easy to implement in engineering.

[0112] For the disengagement clutch, the difference between the KP current value and a first preset value is determined as the first current value. The disengagement reduction amount is determined based on the difference between the first current value and a third preset value (e.g., 0), and the execution time of the speed exchange phase. The disengagement clutch gradually and controllably reduces the hydraulic engagement pressure of the disengagement clutch based on the disengagement reduction amount, so that it can still provide appropriate damping during speed transition and avoid sudden power changes.

[0113] Step S442: Determine the shift-in increment for the current shift stage based on the target turbine speed, output shaft speed, gear ratio of the shift-in gear, actual turbine speed, and gear ratio of the shift-out gear.

[0114] In this embodiment of the invention, the target slip is determined based on the target turbine speed, output shaft speed, and the gear ratio of the engaged gear, and the actual slip is determined based on the actual turbine speed, output shaft speed, and the gear ratio of the disengaged gear. Next, the difference between the actual slip and the target slip is calculated to obtain the slip difference value. Then, PI gain adjustment is applied to the slip difference value to obtain the increase in speed engagement during the speed exchange phase. The formula for calculating the increase in speed engagement is:

[0115]

[0116]

[0117]

[0118] in, This represents the amount of increase from the replacement; A and B are known parameters. It is the slip difference; It is the target slip; It is the target turbine speed; It is the output shaft speed; It is the gear ratio of the shifted gear; This is the actual slip; This is the actual turbine speed; It is the gear ratio of the shifted gear; It is an integral operation.

[0119] The required torque of the shift-in clutch is adjusted in real time according to the slip difference, thereby controlling the pressure of the shift-in clutch. This ensures that the actual slip of the closed-loop control system follows the change of the target slip, guaranteeing the smoothness of clutch engagement and eliminating shift shock.

[0120] During the speed exchange phase, the input shaft speed gradually transitions to the speed corresponding to the gear ratio of the engaged gear. The current for the engaged gear is controlled by the slip difference, ensuring a smooth exchange of the input shaft speed from the disengaged gear to the engaged gear. Once the gear ratio meets the shift requirements, the speed exchange phase ends, and the rapid voltage boost phase begins.

[0121] Optionally, the current adjustment includes an increase in shift-in and a decrease in shift-out. Regarding how to determine the decrease in shift-out of the shift-out clutch and the increase in shift-in of the shift-in clutch in each shift stage using the shift type, a possible implementation method is provided below. Figure 1 The sub-steps of step S40 may include: Step S450: If the shift type is a non-powered upshift or a powered downshift and the current shift stage is a speed exchange stage, determine the second current value based on the preset KP current value and the second preset value.

[0122] In this embodiment of the invention, when a speed exchange phase is entered by upshifting without power or downshifting with power, the sum of the KP current value and the second preset value is determined as the second current value.

[0123] Step S451: Determine the reduction amount of the shift-out gear in the current shift stage based on the target turbine speed, output shaft speed, gear ratio of the engaged gear, actual turbine speed, and gear ratio of the disengaged gear.

[0124] Similarly, referring to the calculation formula for the increase in speed during the shift-in phase of a powered upshift or unpowered downshift, the decrease in speed during the current shift-out phase is determined. By gradually reducing the decrease in speed during the shift-out phase, the shift-out current value of the shift-out clutch is reduced, thereby controllably weakening the hydraulic engagement pressure of the shift-out clutch. This causes the relative speed difference between the master and slave ends of the shift-out clutch to gradually decrease, thus completing the speed phase exchange.

[0125] Step S452: Determine the shift-in increase amount for the current shift stage based on the preset KP current value and the second current value.

[0126] Meanwhile, the increase in speed exchange stage is determined based on the difference between the second current value and the KP current value, as well as the execution time of the speed exchange stage. This increase is then added to the current value of the speed exchange clutch, and the engagement pressure of the speed exchange clutch is increased in a timely manner. This allows the speed exchange clutch to transition to the input shaft speed only after it has the ability to transmit positive torque.

[0127] It should be noted that as the speed exchange phase of unpowered upshifting is about to end, the torque capacity of the shift-in clutch is reduced by appropriately decreasing the shift-in increment, thereby reducing the impact generated when the shift-in clutch switches from positive torque to negative torque. The speed exchange phase is complete when the slip becomes negative.

[0128] To more clearly explain the gearbox clutch shift control method, the shift control for each shift type is described in detail below.

[0129] As one possible implementation, the clutch pressure control curve for power upshifting is as follows: Figure 3As shown. The control process for powered upshifting is strictly executed in the following four-stage sequence: The first stage is the pre-filling stage (PNUP1): At this point, it has been determined that an upshift is imminent, but the speed or torque shift has not yet begun. The current of the disengaging clutch is slowly reduced (i.e., from the current disengagement current value to the disengagement drive current value at a constant rate), causing its hydraulic pressure to drop to a plateau pressure slightly higher than the torque transmission capacity, ensuring it still maintains its ability to drive the current load. Simultaneously, a short "pulse filling" command is sent to the engaging clutch, rapidly filling its piston chamber with oil, followed by a slow filling with KP current until it reaches KP pressure. This is the state where the friction plates and steel plates have just made contact, but no effective torque has yet been generated. This is equivalent to the new clutch "gently grasping the baton," preparing for a smooth handover later.

[0130] The second stage is the torque exchange stage (PNUP2): At this point, the power transfer officially begins. The disengaging clutch slowly releases oil from its platform pressure (i.e., the disengaging current value decreases at a constant rate from the disengaging drive current value to the first current value), and its transmitted torque decreases smoothly. Simultaneously, the current of the engaging clutch gradually increases from the KP current value (i.e., it increases at a constant rate from the KP current value to the engaging drive current value), causing its transmitted torque to increase synchronously. This interplay ensures that the total output torque on the gearbox turbine shaft remains essentially constant. The torque exchange stage ends when the disengaging clutch torque drops to zero and all torque is now borne by the engaging clutch.

[0131] The third stage is the speed exchange stage (PNUP3): At this point, the shift-in clutch can steadily transmit power, but its speed rhythm has not yet caught up with the requirements of the target gear (because the transmission ratio decreases after upshifting, the ideal input shaft speed should be even lower). By collecting the turbine shaft speed, output shaft speed, and transmission ratio of the shift-out / shift-in gear in real time, the speed deviation between the two is calculated, and the shift-in current value of the shift-in clutch is dynamically adjusted accordingly, so that the input shaft speed smoothly and gradually transitions to the speed corresponding to the shift-in gear, just like coasting deceleration, without sudden braking causing jerking or dragging affecting the response.

[0132] The fourth stage is the rapid pressure increase stage (PNUP4): Once the engine speed is precisely matched and the engagement clutch is working stably, the engagement current is immediately increased to the maximum safe value, causing the hydraulic pressure of the engagement clutch to rapidly rise to the lock-up state, completely completing the engagement. At this point, the disengagement clutch is already completely disengaged, and the engagement clutch is firmly engaged. The entire process is clean and efficient, and the driver only feels the vehicle accelerating smoothly without any interruption or shock.

[0133] As another possible implementation, the clutch pressure control curve for non-powered upshifting is as follows: Figure 4 As shown. The control process for non-powered upshifting strictly follows the sequence of the following four stages: The first stage is the pre-filling stage (PFUP1): This stage identifies the intention to coast and upshift while releasing the accelerator, but the engagement clutch is not yet fully engaged, while the disengagement clutch is still transmitting positive torque. The current to the disengagement clutch is slowly reduced (i.e., from the current disengagement current value to the disengagement drive current value at a constant rate), causing its hydraulic pressure to drop to the level of the actual transmitted torque, ensuring it does not suddenly disengage and avoids sudden power changes. Simultaneously, a short "pulse filling" command is sent to the engagement clutch, rapidly filling its piston chamber with oil. Then, a slow filling is performed with the KP current until it reaches the KP pressure, the state where the friction plates just touch the steel plates and can transmit a very small amount of positive torque. This is equivalent to gently engaging the engagement clutch, preparing it for subsequent acceleration.

[0134] The second stage is the speed exchange stage (PFUP2): This is the most crucial step in powerless upshifting. At this time, the engagement clutch cannot transmit negative force yet. It is necessary to continuously drain oil from the disengagement clutch (i.e., determine the amount of current reduction based on the target turbine speed, output shaft speed, gear ratio of the engaged gear, actual turbine speed, and gear ratio of the disengagement gear, and use the amount of current reduction to uniformly reduce the disengagement current value), gradually reducing its engagement pressure, so that the relative speed difference between the master and slave ends of the disengagement clutch slowly decreases.

[0135] Meanwhile, the shift clutch, utilizing its remaining positive torque capacity (i.e., the shift current value is increased uniformly from the KP current value to the second current value), actively "pulls" the input shaft to accelerate its rotation, helping it to quickly approach the higher speed required for shifting gears. When the two speeds are basically the same, that is, when the slip becomes negative, the speed exchange phase ends.

[0136] The third stage is the torque exchange stage (PFUP3): At this point, the engaging clutch has the ability to transmit negative torque, while the disengaging clutch has essentially lost its load-bearing capacity. Simply increasing the engaging current of the engaging clutch at a constant rate to the engaging drive current value allows it to smoothly take over all the reverse torque. Because the speeds are now matched and the slip is minimal, this stage is very short, almost instantaneous, like a baton being firmly passed to the second person; a gentle grip is all it takes.

[0137] The fourth stage is the rapid pressure increase stage (PFUP4): Once the torque has been fully transferred and the engagement clutch is working stably, the engagement current is immediately increased to the maximum safe value, causing the hydraulic pressure of the engagement clutch to rapidly rise to the lock-up state, completely completing the engagement. At this time, the disengagement clutch has already completely disengaged. The entire process is silent and seamless; the driver only feels that the vehicle is gliding more smoothly and the engine speed naturally drops, which is both fuel-efficient and safe.

[0138] As another possible implementation, the clutch pressure control curve for power downshifting is as follows: Figure 5As shown. The power downshift control process is strictly executed in the following four-stage sequence: The first stage is the pre-filling stage (PNDP1): This stage identifies the intention to downshift under load, but the engagement clutch is not yet in effective working condition. The engagement current of the disengagement clutch is slowly reduced (i.e., from the current disengagement current value to the disengagement drive current value at a constant rate), causing its hydraulic pressure to return to the level of the actual transmitted torque, ensuring it does not suddenly disengage and cause power interruption. Simultaneously, a short "pulse filling" command is sent to the engagement clutch, rapidly filling its piston chamber with oil, and then slowly filling it with KP current until it reaches KP pressure. This is the state where the friction plates and steel plates are just in contact, maintaining a weak connection, preparing for subsequent acceleration, but not yet bearing any torque.

[0139] The second stage is the speed exchange stage (PNDP2): This is the most crucial step in power downshifting. At this point, the engagement clutch cannot transmit power yet, so there's no rush to make it "work hard," but rather the focus is on speed regulation. The disengagement clutch is continuously drained (i.e., the amount of current reduction is determined based on the target turbine speed, output shaft speed, gear ratio of the engaged gear, actual turbine speed, and gear ratio of the disengagement gear, and the disengagement current is reduced uniformly using this reduction), gradually lowering its engagement pressure and causing the relative speed difference between the master and slave ends of the disengagement clutch to slowly decrease.

[0140] Meanwhile, to prevent abnormal engine speed increases (i.e., runaway), the current of the shift clutch is appropriately increased (i.e., the shift current value is increased uniformly from the KP current value to the second current value), allowing it to establish a certain engagement pressure in advance. Once the speed approaches the matching point, it can respond immediately. When the turbine shaft speed reaches the ideal speed required for the target gear (i.e., the shift gear), the speed exchange phase ends.

[0141] The third stage is the torque exchange stage (PNDP3): At this point, the engaging clutch has the ability to stably transmit positive torque. The current of the engaging clutch is immediately increased (i.e., the engaging current is increased uniformly to the engaging drive current value), causing its hydraulic pressure to rise rapidly and quickly take over all power output tasks; simultaneously, the current of the disengaging clutch decreases rapidly (i.e., the disengaging current value decreases uniformly to the first current value), completely disengaging from operation. The entire process is tightly paced, aiming to establish a new high-torque output path in the shortest possible time, preventing runaway and ensuring uninterrupted traction.

[0142] The fourth stage is the rapid pressure increase stage (PNDP4): Once the torque has been fully received by the engagement clutch and the system is running smoothly, the current of the engagement clutch is immediately increased to the maximum safe value, causing its hydraulic pressure to rapidly rise to the lock-up state, completely completing the engagement. At this point, the disengagement clutch has already completely disengaged. The entire process is crisp and clean, and the driver only feels an instant increase in traction and greater power when climbing hills, without any jerking or loss of control.

[0143] As another possible implementation, the clutch pressure control curve for powerless downshifting is as follows: Figure 6 As shown. The control process for non-powered downshifting strictly follows the sequence of the following four stages: The first stage is the pre-filling stage (PFDP1): This stage identifies the intention to coast or brake for deceleration and downshift, but the engagement clutch is not yet in effective working condition. The current to the disengagement clutch is slowly reduced (i.e., from the current disengagement current value to the disengagement drive current value at a constant rate), causing its hydraulic pressure to drop to a "plateau pressure" slightly higher than the transmittable torque. This ensures it maintains a weak connection and does not suddenly disengage, preventing a momentary interruption of power flow. Simultaneously, a short "pulse filling" command is sent to the engagement clutch, rapidly filling its piston chamber with oil. Then, a slow filling with the KP current is applied until it reaches the KP pressure. This is the state where the friction plates and steel plates just begin to contact and maintain initial engagement, preparing for a smooth transition later.

[0144] The second stage is the torque exchange stage (PFDP2): At this point, the engagement clutch has the ability to transmit negative torque (because it is in a negative slip state, that is, the turbine shaft rotates slower than required by the target gear, naturally adaptable to reverse drag conditions), while the disengagement clutch is still bearing the drag force. The disengagement clutch is gradually depressurized from the platform pressure (that is, the disengagement current value is reduced at a constant speed from the disengagement drive current value to the first current value), causing the transmitted negative torque to decrease smoothly.

[0145] Simultaneously, the current of the engaging clutch rises steadily from the KP current value to the engaging drive current value, causing the transmitted negative torque to increase synchronously. This interplay ensures that the total drag torque on the transmission turbine shaft remains essentially constant, without any jitter, wobbling, or interruption. This stage ends when the disengaged clutch torque drops to zero and all drag force is stably borne by the engaging clutch.

[0146] The third stage is the speed exchange stage (PFDP3): At this point, the engagement clutch can steadily transmit power, but its "speed rhythm" has not yet caught up with the requirements of the target gear (because the transmission ratio increases after downshifting, the ideal input shaft speed should be higher). By collecting the turbine shaft speed, output shaft speed, and the transmission ratio of the current / target gear in real time, the speed deviation between the two is calculated, and the current of the engagement clutch is dynamically adjusted accordingly. This allows the input shaft speed to rise smoothly and gradually to the speed corresponding to the target gear, just like lightly pressing the accelerator, without sudden jerking or lag affecting the response.

[0147] The fourth stage is the rapid pressure boost stage (PFDP4): Once the engine speed is precisely matched and the engagement clutch is working stably, the engagement current is immediately increased to the maximum safe value, causing the hydraulic pressure of the engagement clutch to rapidly rise to the lock-up state, completely completing the engagement. At this point, the disengagement clutch is already completely disengaged, and the engagement clutch is firmly engaged. The entire process is clean and efficient, and the driver only feels that the vehicle decelerates more smoothly and the engine speed naturally recovers, without any interruption or shock.

[0148] It should be understood that the embodiments of the present invention systematically solve the problems of power interruption and large impact during shifting under load by using turbine torque to represent the load in real time, dynamically planning the stage sequence according to the shift type, and precisely controlling the clutch action according to the current adjustment. Its beneficial effects include: (1) Improve shift smoothness and comfort: slow down the clutch disengagement / engagement rate when the load is heavy to avoid shock. Speed ​​up response when the load is light and shorten the power interruption time, significantly improving the driving experience in high-frequency load changing scenarios such as loaders.

[0149] (2) Reduce wear of the transmission system: Reduce ineffective sliding friction and suppress temperature rise under light load. Extend the controllable sliding friction time under heavy load to alleviate the impact between the friction plate and the steel plate, and simultaneously reduce the load on the gears and shafts, thus extending the service life of the whole machine.

[0150] (3) Optimize power transmission efficiency: build up pressure quickly under light loads to reduce hydraulic and mechanical losses. Under heavy loads, control pressure precisely based on torque feedforward to prevent engine revving or power waste, balancing work efficiency and fuel economy.

[0151] (4) Enhance operational stability and safety: Under heavy load conditions such as loading and climbing, ensure continuous torque transmission, eliminate the risk of slippage caused by power interruption, and improve the inherent safety level under extreme conditions. The overall system achieves intelligent shift control with load self-adaptation, stage reconfigurability, and high robustness.

[0152] Based on the same inventive concept, the basic principle and technical effects of the gearbox clutch shift control device provided in this embodiment are the same as those in the above embodiments. For the sake of brevity, any parts not mentioned in this embodiment can be referred to the corresponding content in the above embodiments.

[0153] Please refer to Figure 7 , Figure 7 This is a block diagram of a gearbox clutch shift control device 300 provided in an embodiment of the present invention. The gearbox clutch shift control device 300 includes a preprocessing module 310 and a processing module 320.

[0154] The preprocessing module 310 is used to respond to shift control commands, determine the turbine torque and shift type based on vehicle operating data; the turbine torque is used to characterize the current operating load; and the execution sequence of each shift stage is determined based on the shift type. The processing module 320 is used to determine the shift-in drive current value and the shift-out drive current value based on the turbine torque; during the shifting process, it determines the current adjustment amount of the current shifting stage based on the shifting type, the shift-in drive current value, the shift-out drive current value, and the shifting current value of the current shifting stage. The processing module 320 is also used to update the shift current value of the current shift stage according to the current adjustment amount, control the shift operation of the current shift stage using the updated shift current value, and enter the next shift stage according to the execution order until the shift operation of the last shift stage is completed.

[0155] In summary, the gearbox clutch shift control device provided in this embodiment of the invention estimates the turbine torque and shift type using vehicle operating data, and uses the turbine torque as a direct representation of the current operating load to quantitatively determine the target drive current values ​​required for each of the engagement and disengagement clutches. Then, based on the shift type, the execution sequence of each shift stage is determined, enabling the control logic to adapt to the power flow characteristics under different operating conditions. Furthermore, in each shift stage, the current adjustment amount adapted to the current load is generated in real time by combining the current actual current value, the target drive current value, and the shift type, thereby implementing differentiated current control of the clutch solenoid valve. Under high load, the rate of current change is slowed to avoid power interruption or shock; under low load, the current response is accelerated to shorten shift time. Ultimately, the entire shift process is controllable, with continuous power transmission and no jerking, significantly improving the shift smoothness, system reliability, and operational continuity of construction machinery under complex load conditions.

[0156] Please refer to Figure 8 This is a block diagram of an engineering vehicle 400 provided in an embodiment of the present invention. The engineering vehicle 400 includes, but is not limited to, heavy or super-heavy engineering machinery such as loaders and cranes. The engineering vehicle 400 includes a gearbox 410 and a controller 420. The controller 420 can execute a computer program to control the gearbox 410 to implement the gearbox clutch shifting control method disclosed in the above embodiments.

[0157] It should be understood that, Figure 8 The structure shown is only a schematic diagram of the engineering vehicle 400. The engineering vehicle 400 may also include components of a larger size. Figure 8 The more or fewer components shown, or having the same Figure 8 The different configurations shown. Figure 8 The components shown can be implemented using hardware, software, or a combination thereof.

[0158] In the several embodiments provided by this invention, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of the invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0159] In addition, the functional modules in the various embodiments of the present invention can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0160] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for controlling gearbox clutch shifting, characterized in that, The method includes: In response to shift control commands, the turbine torque and shift type are determined based on vehicle operating data; the turbine torque is used to characterize the current operating load. The execution order of each shift stage is determined according to the shift type; The input drive current value and the output drive current value are determined based on the turbine torque. During gear shifting, the current adjustment amount for the current shifting stage is determined based on the shifting type, the shift-in drive current value, the shift-out drive current value, and the shifting current value for the current shifting stage. The shift current value of the current shifting stage is updated according to the current adjustment amount. The shifting operation of the current shifting stage is controlled by the updated shift current value. The next shifting stage is entered according to the execution order until the shifting operation of the last shifting stage is completed.

2. The gearbox clutch shifting control method according to claim 1, characterized in that, The execution order of each shift stage is determined according to the shift type, including: If the shift type is a powered upshift or a powerless downshift, the execution sequence of each shift stage is set as the pre-filling stage, torque exchange stage, speed exchange stage, and rapid boost stage. The shifting type is either a non-powered upshift or a powered downshift, and the execution sequence of each shifting stage is set as the pre-filling stage, speed exchange stage, torque exchange stage, and rapid boost stage.

3. The gearbox clutch shifting control method according to claim 1, characterized in that, The current adjustment amount includes an increase in shift-in and a decrease in shift-out, and the shift current value includes a shift-out current value and a shift-in current value; determining the current adjustment amount for the current shift stage based on the shift type, the shift-in drive current value, the shift-out drive current value, and the shift current value for the current shift stage includes: If the current shift stage is a pre-filling stage, the shift reduction amount of the current shift stage is determined based on the shift current value and the shift drive current value of the current shift stage. The shift-in increase amount for the current shift stage is determined based on the shift-in current value of the current shift stage and the preset KP current value.

4. The gearbox clutch shifting control method according to claim 1, characterized in that, The current adjustment amount includes an increase in shift-in and a decrease in shift-out; determining the current adjustment amount for the current shift stage based on the shift type, the shift-in drive current value, the shift-out drive current value, and the shift current value for the current shift stage includes: If the shift type is a powered upshift or a powerless downshift and the current shift stage is a torque exchange stage, the first current value is determined according to the preset KP current value and the first preset value. The shift reduction amount for the current shift stage is determined based on the shift drive current value and the first current value. The shift-in increase amount for the current shift stage is determined based on the preset KP current value and the shift-in drive current value.

5. The gearbox clutch shifting control method according to claim 1, characterized in that, The current adjustment amount includes a shift-in increase; determining the current adjustment amount for the current shift stage based on the shift type, the shift-in drive current value, the shift-out drive current value, and the shift current value for the current shift stage includes: If the shift type is a non-powered upshift and the current shift stage is a torque exchange stage, the second current value is determined according to the preset KP current value and the second preset value. The shift-in increase amount for the current shift phase is determined based on the second current value and the shift-in drive current value.

6. The gearbox clutch shifting control method according to claim 1, characterized in that, The current adjustment amount includes an increase in shift-in and a decrease in shift-out, and the shift current value includes a shift-out current value; determining the current adjustment amount for the current shift stage based on the shift type, the shift-in drive current value, the shift-out drive current value, and the shift current value for the current shift stage includes: If the shift type is a powered downshift and the current shift stage is a torque exchange stage, the first current value and the second current value are determined according to the preset KP current value, the first preset value and the second preset value. The amount of reduction in shifting speed during the current shifting stage is determined based on the shifting current value during the current shifting stage and the first current value. The shift-in increase amount for the current shift phase is determined based on the second current value and the shift-in drive current value.

7. The gearbox clutch shifting control method according to claim 1, characterized in that, The current adjustment amount includes an increase in shift-in and a decrease in shift-out; determining the current adjustment amount for the current shift stage based on the shift type, the shift-in drive current value, the shift-out drive current value, and the shift current value for the current shift stage includes: If the shift type is a powered upshift or a powerless downshift and the current shift stage is a speed exchange stage, the first current value is determined according to the preset KP current value and the first preset value. The shift reduction amount for the current shift stage is determined based on the first current value and the third preset value. The shift-in increment for the current shift stage is determined based on the target turbine speed, output shaft speed, gear ratio of the engaged gear, actual turbine speed, and gear ratio of the disengaged gear.

8. The gearbox clutch shifting control method according to claim 1, characterized in that, The current adjustment amount includes an increase in shift-in and a decrease in shift-out; determining the current adjustment amount for the current shift stage based on the shift type, the shift-in drive current value, the shift-out drive current value, and the shift current value for the current shift stage includes: If the shift type is a non-powered upshift or a powered downshift and the current shift stage is a speed exchange stage, the second current value is determined according to the preset KP current value and the second preset value. The reduction amount of the shift-out gear in the current shift stage is determined based on the target turbine speed, output shaft speed, gear ratio of the engaged gear, actual turbine speed, and gear ratio of the disengaged gear. The shift-in increment for the current shift stage is determined based on the preset KP current value and the second current value.

9. A gearbox clutch shift control device, characterized in that, The device includes: A preprocessing module is used to respond to shift control commands, determine the turbine torque and shift type based on vehicle operating data; the turbine torque is used to characterize the current operating load; and determine the execution sequence of each shift stage based on the shift type. The processing module is used to determine the shift-in drive current value and the shift-out drive current value based on the turbine torque; during the shifting process, it determines the current adjustment amount of the current shifting stage based on the shifting type, the shift-in drive current value, the shift-out drive current value, and the shifting current value of the current shifting stage. The processing module is also configured to update the shift current value of the current shifting stage according to the current adjustment amount, control the shifting operation of the current shifting stage using the updated shifting current value, and enter the next shifting stage according to the execution order until the shifting operation of the last shifting stage is completed.

10. An engineering vehicle, characterized in that, It includes a gearbox and a controller, the controller being able to execute a computer program to control the gearbox to implement the gearbox clutch shift control method according to any one of claims 1-8.

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