Four-speed power shifting tractor transmission system control system and control method

Abstract

The invention provides a four-speed power gear-shifting tractor transmission system control system and a control method, and belongs to the technical field of tractor transmission control, the control system comprises a tractor complete machine, and a clutch pedal, a reversing handle, an instrument and a gear-shifting handle are installed in the tractor complete machine; the tractor is characterized in that an engine controller, a gearbox controller, a proportional valve assembly, a power gear shifting transmission system and a mechanical stepped gear transmission system are further installed in the whole tractor; a rotating speed sensor used for detecting the rotating speed in the gearbox is installed on the gearbox, a clutch oil supply pressure sensor is installed below the clutch, and a temperature sensor used for detecting the working temperature of the power gear shifting transmission system is installed on the power gear shifting transmission system. Wherein the engine controller, the instrument and the gearbox controller are connected through a CAN bus; the clutch pedal, the reversing handle, the gear shifting handle, the rotating speed sensor, the clutch oil supply pressure sensor, the temperature sensor and the proportional valve assembly are connected with a gearbox controller.

Description

Technical Field

[0001] The present invention belongs to the technical field of tractor transmission control, and particularly relates to a four-speed power shift tractor transmission system control system and a control method thereof. Background Art

[0002] The power shift and power reverse technologies of tractors are the core functions of the power transmission system of modern agricultural equipment. Currently, most domestic small tractors are equipped with conventional manual mechanical shift transmissions, such as sliding gear shifts, dog clutch shifts, and synchronizer shifts. These mechanical shift transmissions require direct operation by the driver, resulting in high labor intensity. Additionally, the driver needs to have certain operating experience and be proficient in controlling the clutch and mechanical gear operations to use the tractor for work effectively.

[0003] Traditional tractors use mechanical shift or reverse structures, and the power needs to be cut off by the clutch before changing gears or directions, resulting in an interruption of power transmission. In complex working scenarios with frequent gear shifting (such as plowing, sowing, harvesting, etc.), the power interruption will reduce the working continuity and prolong the working cycle. Especially in heavy-load or ramp working conditions, the delayed power recovery is likely to cause traction fluctuations, affecting the working quality and efficiency.

[0004] Mechanical shifting relies on the driver to manually operate the clutch and shift lever, and the direction gear needs to be switched after stopping when reversing. Such operations are likely to cause driver fatigue during long-term work and require relatively high operating experience. In addition, the shifting shock and jerks will reduce the driving comfort and restrict the control accuracy of the tractor in fine operations.

[0005] Modern agriculture is evolving towards intelligence and automation, requiring tractors to have the capabilities of real-time load perception, adaptive gear shifting, and unmanned operation. Due to the lack of cooperation with on-vehicle sensors and navigation systems, traditional power shift / reverse systems are difficult to achieve the optimal gear matching under dynamic working conditions (such as automatically adjusting the traction force according to soil moisture), restricting the implementation and application of precision agriculture technologies. Summary of the Invention

[0006] In view of this, the present invention provides a four-speed power shift tractor transmission system control system and a control method thereof, which can solve the problem that conventional power reverse tractors need to stop for gear shifting during the working process of the current power shift tractor transmission system. At the same time, the corresponding control method of the present invention can reduce the clutch speed difference, effectively improve the working efficiency while prolonging the service life of the clutch.

[0007] The present invention is implemented as follows. The present invention provides a control system for the transmission of a four-speed power shift tractor. The system specifically includes the whole tractor, in which a clutch pedal, a reversing handle, an instrument panel, and a shift handle are installed. It is characterized in that an engine controller, a transmission controller, a proportional valve assembly, a power shift transmission system, and a mechanical stepped gear transmission system are also installed in the whole tractor. A speed sensor for detecting the internal speed of the transmission is installed on the transmission, a clutch oil supply pressure sensor is installed below the clutch, and a temperature sensor for detecting the working temperature of the transmission system is installed on the power shift transmission system. Among them, the engine controller, the instrument panel, and the transmission controller are connected through the CAN bus. The engine controller sends data related to the working state of the engine to the CAN bus and outputs it to the instrument panel through the CAN bus, and the instrument panel displays the relevant data. The transmission controller reads the corresponding data of the engine speed and engine load from the CAN bus, judges the working state, and executes control actions. The clutch pedal, the reversing handle, the shift handle, the speed sensor, the clutch oil supply pressure sensor, the temperature sensor, and the proportional valve assembly are connected to the transmission controller.

[0008] On the basis of the above technical solution, the control system proposed by the present invention can be further improved as follows: Furthermore, the relevant data includes engine speed, engine load, fuel consumption, water temperature, and the gear state of the transmission system.

[0009] Furthermore, a clutch button switch for cutting off or restoring the clutch, a gear up button switch for increasing the gear, and a gear down button switch for decreasing the gear are installed on the shift handle. When the clutch button switch is pressed, the clutch is cut off, and when it is lifted, the clutch is restored.

[0010] Furthermore, the proportional valve assembly includes an FL clutch valve, an FH clutch valve, an L clutch valve, an H clutch valve, and an R clutch valve. The above 5 proportional valves are independently controlled by the transmission controller. The power shift transmission system includes an FL clutch, an FH clutch, an L clutch, an H clutch, and an R clutch. The above 5 clutches correspond to the 5 proportional valves one by one and are independently controlled. Among them, when the forward F1 gear is working, the FL clutch and the L clutch work simultaneously. When the forward F2 gear is working, the FL clutch and the H clutch work simultaneously. When the reverse R1 gear is working, the R clutch and the L clutch work simultaneously.

[0011] The present invention also provides a control method for the transmission control system of a four-speed power shift tractor. The control method specifically includes the power shift control principle and process, the power shift control principle and process, and the mechanical shift control principle and process. Among them, the mechanical shift control principle and process include handle button control, foot clutch control, and half-clutch control of the foot clutch.

[0012] Based on the above technical solutions, the control method provided by the present invention can be further improved as follows: Further, the power shift control principle and process are divided into normal power shift and quick power shift; The normal power shift specifically includes: When the tractor changes from the forward F gear to the reverse R gear, the shift lever changes from the forward gear state to the reverse gear state, the F switch signal state in the shift lever changes from high to low, and the R switch signal changes from low to high; the transmission controller closes the FL clutch valve and the L clutch valve, and the speed measured by the speed sensor decreases until the speed drops to zero; the R switch signal in the shift lever becomes high, and the pre-shift work is completed. The transmission controller drives the R clutch valve and the L clutch valve to work, controls the transmission system to start rotating in the reverse direction, and the speed rises in the reverse direction to a stable speed, and the shift is completed; when the tractor changes from the reverse R gear to the forward F gear, the specific process is opposite to the above. The quick power shift specifically includes: When the tractor changes from the forward F gear to the reverse R gear, the shift lever quickly changes from the forward gear state to the reverse gear state, the transmission controller closes the FL clutch valve and the L clutch valve, and the speed measured by the speed sensor decreases. The R switch signal in the shift lever directly becomes high; the transmission controller determines according to the speed data measured by the speed sensor that the speed has not yet decreased to the appropriate shift speed range at this time, and the transmission controller does not control the corresponding valve to work. At this time, the vehicle has no driving force and the speed continues to decrease; until the speed data measured by the speed sensor reaches the appropriate shift speed, the transmission controller drives the R clutch valve and the L clutch valve to work, and the transmission system changes from rotating forward at low speed to rotating in the reverse direction, and the speed rises in the reverse direction; when the tractor changes from the reverse R gear to the forward F gear, the specific process is opposite to the above.

[0013] Further, the power shift control principle and process specifically include the tractor rising from the forward F1 gear to the forward F2 gear and rising from the forward F2 gear to the forward F3 gear; The specific content of the tractor rising from the forward F1 gear to the forward F2 gear is as follows: The tractor is working in the forward F1 gear. The driver presses the upshift button switch on the shift lever, and the upshift button switch signal changes from low to high. The transmission controller controls the FL clutch valve, the L clutch valve, and the H clutch valve to work. The speed of the transmission system increases and then tends to be stable. The current speed is higher than the speed before upshifting, and the tractor is working in the forward F2 gear; The tractor is working in the forward F2 gear. The driver presses the upshift button switch on the shift lever. The signal of the upshift button switch changes from low to high. The transmission controller controls the FL clutch valve, FH clutch valve, L clutch valve, and H clutch valve to work. The rotational speed of the driveline increases and then stabilizes. The current rotational speed is higher than that before upshifting. The tractor is working in the forward F3 gear; During downshifting, the specific content is opposite to the above.

[0014] Furthermore, the specific content controlled by the handle button is as follows: The tractor is working in the forward F1 gear. The driver presses the clutch button on the shift lever. The signal state of the clutch button changes from low to high. The transmission controller senses the signal change and controls the FL clutch valve and L clutch valve to close. The driveline loses driving force and the rotational speed decreases; during this process, the signal of the clutch button is always in the high level state; The driver toggles the shift lever to change the mechanical gear. After completion, the driver releases the clutch button. The signal state of the clutch button changes from high to low. The transmission controller senses the signal change and controls the FL clutch valve and L clutch valve to work. The rotational speed of the driveline stops decreasing and then increases, and the rotational speed rises to the previous speed.

[0015] Furthermore, the tractor is working in the forward F1 gear. The driver steps on the clutch pedal. The signal of the clutch pedal changes from low to high. The transmission controller senses the signal change and controls the FL clutch valve and L clutch valve to close; the driveline loses driving force and the rotational speed decreases. During this process, the signal of the clutch pedal is always in the high level state; The driver toggles the shift lever to change the mechanical gear. After completion, the driver releases the clutch pedal; the signal of the clutch pedal changes from high to low. The transmission line controller senses the signal change and controls the FL clutch valve and L clutch valve to work. The rotational speed of the driveline stops decreasing and rises rapidly, and the rotational speed rises back to the previous speed.

[0016] Furthermore, the specific content of the foot-operated clutch semi-clutch control is as follows: The tractor is working in the forward F1 gear. The driver steps on the clutch pedal. The signal of the clutch pedal changes from low to high. At this time, the transmission line controller senses the signal change and controls the FL clutch valve and L clutch valve to close. The driveline loses power and the rotational speed decreases until it reaches zero; The driver slowly releases the clutch pedal. The signal of the clutch pedal slowly rises. At this time, the transmission controller controls the drive current of the FL clutch valve and L clutch valve according to the proportion of the current signal of the clutch pedal in the entire signal range. The driving torque of the driveline gradually increases and the rotational speed gradually rises; When the speed reaches the required value, keep the clutch pedal stable at the current position. The transmission controller controls the drive currents of the FL clutch valve and the L clutch valve to remain stable, the clutch transmission maintains a stable rotational speed difference state, the driveline maintains low-speed transmission, and the rotational speed stabilizes at the current lower speed; Abandon the semi-clutch operation and fully release the clutch pedal. The signal of the clutch pedal becomes the lowest. The transmission controller drives the FL clutch valve and the L clutch valve to work, and the rotational speed of the driveline continues to rise until it reaches the previous speed.

[0017] The beneficial effects of a four-speed power shift tractor driveline control system and its control method proposed by the present invention are as follows: 1. During the power shift process, the clutch in the previous state is fully disengaged and then combined with the clutch of the gear after shifting. The rotational speed differences of the driveline when the two clutches participate in the shift are synchronized, reducing the speed difference on the clutch and increasing the service life of the clutch; 2. A driveline rotational speed sensor is added. When the shift speed is too high, the shift operation control is not started, which is safer. At the same time, the clutch will not have too large a speed difference during high-speed shifting, and the clutch life is further improved.

[0018] 3. A clutch button is added to the mechanical shift lever. When pressed, the two clutches are completely disengaged. Compared with the conventional power shift where only one clutch is disengaged, the separation of the driveline is more complete. Changing the mechanical gear will be lighter, easier, the shifting speed will be faster, and it will also save effort.

[0019] 4. The F1 / F2 / F3 / F4&R1 / R2 gears are independent of the power shift. When the gear speed is not appropriate during load operation, the power shift can be operated to change the speed. There are 4 power shifts for forward movement, further reducing the working conditions where the conventional power shift tractor needs to stop for shifting, and further improving the operation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0021] Figure 1 It is a schematic diagram of the overall structure of the control system; Figure 2 It is a diagram of the mechanical shift lever of the control system; Figure 3 It is a schematic diagram of the proportional valve assembly of the control system; Figure 4 It is a schematic diagram of the driveline of the control system; Figure 5 It is a schematic diagram of the gear and clutch combination relationship of the control system; Figure 6 It is a control schematic diagram of power shift in the control method; Figure 7 It is a control schematic diagram of quick power shift in the control method; Figure 8 It is a process diagram of power shift in the control method; Figure 9 It is a control schematic diagram of power shift in the control method; Figure 10 It is a control schematic diagram of power shift under another working condition in the control method; Figure 11 It is a process diagram of power shift in the control method; Figure 12 It is a control schematic diagram of the handle clutch button in the control method; Figure 13 It is a control process diagram of the handle clutch button in the control method; Figure 14 It is a control schematic diagram of the foot-operated clutch in the control method; Figure 15 It is a control schematic diagram of the half-clutch of the foot-operated clutch in the control method; Figure 16 It is a control process diagram of the foot-operated clutch in the control method.

[0022] In the attached drawings, the list of components represented by each label is as follows: 1. Whole tractor; 2. ECU; 3. Clutch pedal; 4. Reversing handle; 5. Instrument; 6. TCU; 7. Shift handle; 7.1. Clutch button switch; 7.2. Upshift button switch; 7.3. Downshift button switch; 8. Speed sensor; 9. Clutch oil supply pressure sensor; 10. Temperature sensor; 11. Proportional valve assembly; 11.1. FL clutch valve; 11.2. FH clutch valve; 11.3. L clutch valve; 11.4. H clutch valve; 11.5. R clutch valve; 12. Power shift transmission system; 13. Mechanical stepped gear transmission system. Detailed implementation method

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] Figure 1 Shown is a schematic diagram of the overall structure of a power shift tractor transmission system control system of the present invention.

[0025] The tractor 1 is equipped with an ECU 2 (engine controller) for controlling engine operation, a clutch pedal 3, a reversing handle 4, an instrument 5, a TCU 6 (transmission controller), a shift handle 7, a speed sensor 8 for collecting real-time transmission speed values, a clutch oil supply pressure sensor 9 for detecting clutch oil pressure, a temperature sensor 10 for detecting the internal temperature of the transmission, a proportional valve assembly 11, a power shift transmission system 12 for realizing rapid shifting during tractor operation, and a mechanical stepped gear transmission system 13 for assisting shifting operations.

[0026] ECU2, instrument 5 and TCU6 are connected via the CAN bus. ECU2 sends the engine working status related data (such as engine speed, oil pressure, water temperature, etc.) to the CAN bus, and instrument 5 displays the corresponding related data (such as engine speed, oil pressure, water temperature, transmission gear status, etc.) for the driver to view and judge.

[0027] TCU6 reads the required information (such as engine speed, engine load, etc.) from the CAN bus to determine the working status and perform control actions.

[0028] The clutch pedal 3, the reversing handle 4, the shift handle 7, the speed sensor 8, the clutch oil supply pressure sensor 9, the temperature sensor 10, and the proportional valve assembly 11 are connected to the TCU 6.

[0029] The speed sensor 8 is used to measure the speed and rotation direction of the output shaft of the power shift transmission and send the data to the TCU6.

[0030] The clutch oil supply pressure sensor 9 is used to monitor the hydraulic system pressure, and the temperature sensor 10 is used to monitor the operating temperature of the transmission system to ensure that the system operates in a normal state.

[0031] The different states of the driver's operation of the reversing handle 4 can be sent to the TCU 6, including the forward (F gear) state, the neutral (N gear) state, and the reverse (R gear) state, corresponding to the three working states of power reversing.

[0032] The mechanical stepped gear transmission system 13 is a conventional mechanical shifting transmission system, and different gears (such as A gear, B gear, C gear, D gear, etc.) are changed by toggling the shift handle 7.

[0033] Figure 2 Shown is the mechanical shift lever diagram of a four-speed power shift tractor powertrain control system according to the present invention.

[0034] A clutch button switch 7.1, a gear up button switch 7.2, and a gear down button switch 7.3 are installed on the shift lever 7.

[0035] When the clutch button switch 7.1 is pressed, a control signal is sent to the TCU 6 to start performing the interrupted clutch operation; at this time, the driver can quickly move the shift lever 7 to the target mechanical gear position, and then release the clutch button switch 7.1 to complete the mechanical gear shift operation. When the gear up button switch 7.2 is pressed, a control signal is sent to the TCU 6 to start performing the power shift upshift operation; when the gear down button switch 7.3 is pressed, a control signal is sent to the TCU 6 to start performing the power shift downshift operation.

[0036] Figure 3 Shown is the schematic diagram of the proportional valve assembly of a four-speed power shift tractor powertrain control system according to the present invention.

[0037] The proportional valve assembly 11 includes an FL clutch valve 11.1, an FH clutch valve 11.2, an L clutch valve 11.3, an H clutch valve 11.4, and an R clutch valve 11.5. The above 5 valves are independently controlled by the TCU 6.

[0038] Figure 4 Shown is the schematic diagram of the powertrain of a four-speed power shift tractor powertrain control system according to the present invention.

[0039] There are 5 independent clutches in the power shift powertrain 12, namely the L clutch, the H clutch, the FL clutch, the FH clutch, and the R clutch. The valves in the proportional valve assembly 11 correspond to the clutches one by one to control the corresponding clutches to work.

[0040] Figure 5 Shown is the schematic diagram of the gear position and clutch combination relationship of a four-speed power shift tractor powertrain control system according to the present invention.

[0041] When in the forward F1 gear, the FL clutch and the L clutch need to work simultaneously; when in the forward F2 gear, the FL clutch and the H clutch need to work simultaneously; when in the reverse R1 gear, the R clutch and the L clutch need to work simultaneously.

[0042] Figure 6 Shown is the schematic diagram of the normal power reversing control of the power shift tractor powertrain according to the present invention. The lines in the legend represent the changes in the component status signals or control signals.

[0043] When the tractor is working in the F1 gear and the driver operates the reversing handle 4 to change from the forward gear (F gear) state to the reverse gear (R gear) state, the F switch signal state in the reversing handle 4 changes from high to low, and then the R switch changes from low to high. The TCU6 closes the FL clutch valve 11.1 and the L clutch valve 11.3, and the rotational speed n8 measured by the rotational speed sensor 8 decreases until it reaches zero. After the R switch signal in the reversing handle 4 becomes high, the TCU6 drives the R clutch valve 11.5 and the L clutch valve 11.3 to work according to the programmed curve, and the driveline starts to rotate in the reverse direction, and it can be seen that the rotational speed n8 rises in the reverse direction to the stable rotational speed.

[0044] Figure 6 and Figure 7 Both belong to the reversing operation process, and the signal processing process of the TCU6 is the same, and the same process diagram can be used to describe it. Figure 8 It is the power reversing process diagram.

[0045] The TCU receives the states of the F switch and the R switch in the reversing handle 4, as well as the measured rotational speed n8 of the rotational speed sensor 8, and judges the gear state in which the current program is executed. For example, the initial state in this example is the F1 gear. When it is monitored that the F switch signal state in the reversing handle 4 changes from high to low, the TCU cuts off the control signals of the currently working FL clutch valve and the L clutch valve. When it is monitored that the R switch in the reversing handle 4 changes from low to high, the TCU6 judges whether the rotational speed n8 is within the allowable reversing range. If the condition is met, the TCU controls the R clutch valve and the L clutch valve according to the set curve, and combines the corresponding clutches.

[0046] The above-mentioned set curve is obtained by testing curves with different slopes and change situations to obtain the clutch valve control curve with the best performance, and this curve is stored in the TCU as the clutch valve control curve.

[0047] The first advantage of the present invention is that the two clutches that transmit power in the early stage of the power reversing process are also disengaged, and then the two clutches after reversing are combined. Then, the rotational speed difference of the driveline is synchronized when the two clutches participate in reversing, the speed difference on the clutches is reduced, and the service life of the clutches is improved.

[0048] Figure 7 The schematic diagram of the fast power reversing control of the driveline of the power shift tractor of the present invention is shown.

[0049] When the tractor is working in the F1 gear and the driver operates the reversing handle 4 to quickly change from the forward gear (F gear) state to the reverse gear (R gear) state, the TCU6 closes the FL clutch valve 11.1 and the L clutch valve 11.3. The rotational speed n8 measured by the rotational speed sensor 8 decreases, but does not decrease to a suitable reversing rotational speed range close to 0. After the R switch signal in the reversing handle 4 becomes high, the TCU6 determines that the suitable reversing rotational speed range has not been reached, does not control the valve to work, the vehicle has no driving force, and the rotational speed n8 continues to decrease.

[0050] When the rotational speed n8 drops to the allowable reversing rotational speed range, the TCU6 drives the R clutch valve 11.5 and the L clutch valve 11.3 to work according to the programmed curve. The power transmission system changes from rotating forward at low speed to rotating in reverse, and it can be seen that the rotational speed n8 rises in the reverse direction to a stable rotational speed.

[0051] Figure 9 This is the schematic diagram of the power shift control of the power shift transmission system of the present invention for a tractor.

[0052] When the tractor is working in the F1 gear and the driver presses the upshift push-button switch 7.2 on the shift handle 7, the signal state of the push-button switch 7.2 changes from low to high. The TCU6 drives the FL clutch valve 11.1, the L clutch valve 11.3, and the H clutch valve 11.4 to work according to the programmed curve. The rotational speed of the power transmission system increases and then tends to be stable. It can be seen that the rotational speed n8 is higher than before the operation, and the tractor is working in the F2 gear.

[0053] Figure 10 This is the schematic diagram of the power shift control of another working condition of the power shift transmission system of the present invention for a tractor.

[0054] When the tractor is working in the F2 gear and the driver presses the upshift push-button switch 7.2 on the shift handle 7, the signal state of the upshift push-button switch 7.2 changes from low to high. The TCU6 drives the FL clutch valve 11.1, the FH clutch valve 11.2, the L clutch valve 11.3, and the H clutch valve 11.4 to work according to the programmed curve. The rotational speed of the power transmission system increases and then tends to be stable. It can be seen that the rotational speed n8 is higher than before the operation, and the tractor is working in the F3 gear.

[0055] Figure 11 This is the process diagram of the power shift of the power shift transmission system of the present invention for a tractor.

[0056] The TCU first judges the current working state and gear state. In this example, the tractor is in the F1 gear state. When the TCU monitors that the state of the upshift push-button switch 7.2 changes from low to high, the TCU controls the corresponding valve according to the set curve, combines the corresponding clutch, and then updates the gear state in the TCU and stores it in the TCU.

[0057] The set curve in the above power shift is obtained by testing curves with different slopes and change conditions to obtain the clutch valve control curve with the best performance, and this curve is stored in the TCU as the clutch valve control curve.

[0058] When performing a power downshift, the working conditions of the FL clutch valve 11.1, FH clutch valve 11.2, L clutch valve 11.3, and H clutch valve 11.4 are similar to those Figure 9 and Figure 10 described in, and the rotational speed n8 will be lower than before the operation. The control method diagram for this working condition is not shown here.

[0059] Figure 12 This is the schematic diagram of the control of the clutch button on the transmission system handle of the power shift tractor of the present invention.

[0060] When the tractor is working in the F1 gear and the driver presses the clutch button switch 7.1 on the shift handle 7, the signal state of the clutch button switch 7.1 changes from low to high, and the TCU 6 closes the FL clutch valve 11.1 and the L clutch valve 11.3. There is no driving force in the transmission system, and it can be seen that the rotational speed n8 starts to decrease.

[0061] The driver toggles the shift handle 7 to change to a suitable mechanical gear. After completion, the driver releases the clutch button switch 7.1, and the TCU 6 drives the FL clutch valve 11.1 and the L clutch valve 11.3 to work according to the program set curve. The rotational speed of the transmission system stops decreasing and then increases, and the rotational speed n8 rises back to the previous speed.

[0062] Figure 13 This is the process diagram of the control of the clutch button on the transmission system handle of the power shift tractor of the present invention.

[0063] The TCU first determines the gear state of the currently executing program. In this example, the tractor is in the F1 gear state. When it monitors that the state of the clutch button switch 7.1 on the shift handle 7 changes from low to high, the TCU cuts off the control signals of the FL clutch valve 11.1 and the L clutch valve 11.3. Until the TCU monitors that the switch 7.1 changes from high to low, the TCU controls the FL clutch valve 11.1 and the L clutch valve 11.3 according to the set curve and engages the corresponding clutch.

[0064] The set curve in the above control process of the handle clutch button is obtained by testing curves with different slopes and change conditions to obtain the clutch valve control curve with the best performance, and this curve is stored in the TCU as the clutch valve control curve.

[0065] Figure 14 This is the schematic diagram of the control of the foot-operated clutch on the transmission system of the power shift tractor of the present invention.

[0066] When the tractor is working in the F1 gear, the driver steps on the clutch pedal 3, and the signal of the clutch pedal 3 changes from low to high. The TCU 6 closes the FL clutch valve 11.1 and the L clutch valve 11.3. There is no driving force in the driveline, and it can be seen that the rotational speed n8 begins to decline. The driver can shift the gear lever 7 to change to a suitable mechanical gear. After completion, the driver releases the clutch pedal 3. The TCU 6 drives the FL clutch valve 11.1 and the L clutch valve 11.3 to work according to the programmed curve. The rotational speed of the driveline stops declining and then rises, and the rotational speed n8 rises back to the previous speed.

[0067] Figure 15 It is the schematic diagram of the foot-operated clutch semi-clutch control of the driveline of the power shift tractor of the present invention.

[0068] When the tractor is working in the F1 gear, the driver steps on the clutch pedal 3, and the signal of the clutch pedal 3 changes from low to high. The TCU 6 closes the FL clutch valve 11.1 and the L clutch valve 11.3. There is no driving force in the driveline, and it can be seen that the rotational speed n8 begins to decline until the speed is zero.

[0069] When the driver slowly releases the clutch pedal 3, the TCU 6 proportionally controls the drive current of the FL clutch valve 11.1 and the L clutch valve 11.3 according to the signal of the clutch pedal 3. The driving torque of the driveline gradually increases, and the rotational speed n8 also gradually rises.

[0070] When the driver feels that the speed is appropriate, the driver will stabilize the clutch pedal 3 at the current position. Then the TCU 6 controls the drive current of the FL clutch valve 11.1 and the L clutch valve 11.3 to remain stable. Then the clutch transmission maintains a stable rotational speed difference state, enabling the driveline to transmit at a low speed, and the rotational speed n8 is stable at the current lower speed.

[0071] When the driver no longer needs semi-clutch operation, the driver fully releases the clutch pedal 3, and the signal of the clutch pedal 3 becomes the lowest. The TCU 6 drives the FL clutch valve 11.1 and the L clutch valve 11.3 to work according to the programmed curve. The rotational speed of the driveline continues to rise, and it can be seen that the rotational speed n8 rises to the previous speed.

[0072] Figure 14 and Figure 15 Both belong to the process of foot-operated clutch operation. The signal processing process of the TCU is the same, and the same process diagram can be used to describe it.

[0073] Figure 16 It is the process diagram of the foot-operated clutch control of the driveline of the power shift tractor of the present invention.

[0074] The TCU receives the status of the F switch and R switch in the reversing handle 4, as well as the signal of the clutch pedal 3 sensor, and determines the gear status of the current program execution. For example, the initial state in this instance is the F1 gear. When it monitors that the signal of the clutch pedal 3 sensor starts to rise from the lowest value, the TCU cuts off the control signals of the FL clutch valve 11.1 and the L clutch valve 11.3, disconnecting the corresponding clutches. When the TCU monitors that the signal of the clutch pedal 3 changes from high to low and reaches the lowest value, the TCU controls the FL clutch valve 11.1 and the L clutch valve 11.3 according to the set curve to engage the corresponding clutches.

[0075] If the TCU monitors that the signal of the clutch pedal 3 changes from high to low and stays at the intermediate value, the TCU controls the FL clutch valve 11.1 and the L clutch valve 11.3 according to the percentage of clutch engagement corresponding to the percentage of the set curve, thereby controlling the engagement degree of the corresponding clutches, enabling the clutches to work in the semi - engaged state until the clutch pedal reaches the highest value, at which time the control values of the corresponding FL clutch valve 11.1 and L clutch valve 11.3 reach the maximum and the corresponding clutches are fully engaged.

[0076] The above - mentioned set curve is obtained by testing curves with different slopes and change situations to obtain the clutch valve control curve with the best performance, and this curve is stored in the TCU as the clutch valve control curve.

[0077] As mentioned above, this is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A four-speed power shift tractor transmission control system, comprising a tractor complete machine, wherein a clutch pedal, a reversing handle, an instrument, and a shift handle are installed in the tractor complete machine; characterized in that: The tractor is also equipped with an engine controller, a gearbox controller, a proportional valve assembly, a power shift transmission system, and a mechanical step-shift transmission system; a speed sensor for detecting the internal speed of the gearbox is installed on the gearbox, a clutch oil supply pressure sensor is installed under the clutch, and a temperature sensor for detecting the working temperature of the transmission system is installed on the power shift transmission system; The engine controller, the instrument and the transmission controller are connected via a CAN bus; the engine controller sends data related to the engine working status to the CAN bus, and outputs it to the instrument via the CAN bus, and the instrument displays the relevant data; The transmission controller reads the corresponding data of engine speed and engine load from the CAN bus, determines the working status and executes control actions; The clutch pedal, the reversing handle, the shifting handle, the rotation speed sensor, the clutch oil supply pressure sensor, the temperature sensor, and the proportional valve assembly are connected to the transmission controller.

2. A four-speed power shift tractor transmission control system according to claim 1, characterized in that: The relevant data include engine speed, oil pressure, water temperature, and transmission gear status.

3. A four-speed power shift tractor transmission control system according to claim 1, characterized in that: The shift handle is equipped with a clutch button switch for cutting off or restoring the clutch, an upshift button switch for increasing the gear, and a downshift button switch for reducing the gear; wherein the clutch button switch is cut off when pressed, and the clutch is restored when lifted.

4. A four-speed power shift tractor transmission control system according to claim 1, characterized in that: The proportional valve assembly includes FL clutch valve, FH clutch valve, L clutch valve, H clutch valve, and R clutch valve; the above five proportional valves are independently controlled by the transmission controller; the power shift transmission system includes FL clutch, FH clutch, L clutch, H clutch, and R clutch; the above five clutches correspond to five proportional valves one by one and are independently controlled; Among them, when the forward F1 gear is working, the FL clutch and the L clutch work at the same time; when the forward F2 gear is working, the FL clutch and the H clutch work at the same time; when the reverse R1 gear is working, the R clutch and the L clutch work at the same time.

5. A four-speed power shift tractor transmission control method, characterized in that: The control method is applied to a four-speed power shift tractor transmission system control system as described in any one of claims 1-4, and the control method specifically includes power reversing control principle and process, power shift control principle and process, and mechanical shift control principle and process; wherein the mechanical shift control principle and process include handle button control, foot clutch control, and foot clutch semi-clutch control.

6. A four-speed power shift tractor transmission control method according to claim 5, characterized in that: The power switching control principle and process are divided into normal power switching and fast power switching; Normal power switching specifically includes: The tractor changes from forward F gear to reverse R gear, the reversing handle changes from forward gear state to reverse gear state, the F switch signal state in the reversing handle changes from high to low, and the R switch signal changes from low to high; the transmission controller closes the FL clutch valve and the L clutch valve, and the speed measured by the speed sensor decreases until the speed drops to zero; the R switch signal in the reversing handle becomes high, the pre-shifting work is completed, the transmission controller drives the R clutch valve and the L clutch valve to work, controls the transmission system to start reverse rotation, the speed rises in the reverse direction to a stable speed, and the gear shift is completed; the tractor changes from reverse R gear to forward F gear, and the specific process is opposite to the above; Rapid power switching specifically includes: The tractor changes from forward gear F to reverse gear R, and the reversing handle quickly changes from the forward gear state to the reverse gear state. The transmission controller closes the FL clutch valve and the L clutch valve, the speed measured by the speed sensor decreases, and the R switch signal in the reversing handle directly becomes high; the transmission controller determines that the speed has not yet dropped to the appropriate reversing speed range based on the speed data measured by the speed sensor, and the transmission controller does not control the corresponding valve to work. At this time, the vehicle has no driving force and the speed continues to decrease; until the speed data measured by the speed sensor reaches the appropriate reversing speed, the transmission controller drives the R clutch valve and the L clutch valve to work, and the transmission system changes from low-speed forward rotation to reverse rotation, and the speed increases in the opposite direction; the tractor changes from reverse R gear to forward gear F, and the specific process is opposite to the above.

7. A four-speed power shift tractor transmission control method according to claim 5, characterized in that: The power shift control principle and process specifically include the tractor shifting from forward F1 gear to forward F2 gear, and from forward F2 gear to forward F3 gear; The specific contents of the tractor shifting from forward F1 gear to forward F2 gear are as follows: The tractor is working in the forward F1 gear, the driver presses the upshift button switch on the shift handle, the upshift button switch signal changes from low to high, the transmission controller controls the FL clutch valve, L clutch valve, and H clutch valve to work, the transmission system speed increases and then tends to be stable, the current speed is higher than the speed when the gear is not upshifted, and the tractor is working in the forward F2 gear; The tractor is working in the forward F2 gear, the driver presses the upshift button switch on the shift handle, the upshift button switch signal changes from low to high, the transmission controller controls the FL clutch valve, FH clutch valve, L clutch valve, and H clutch valve to work, the transmission system speed increases and then tends to be stable, the current speed is higher than the speed when the gear is not upshifted, and the tractor is working in the forward F3 gear; When downshifting, the specific contents are opposite to the above.

8. A four-speed power shift tractor transmission control method according to claim 5, characterized in that: The specific contents of the handle button control are as follows: The tractor is working in the forward F1 gear. The driver presses the clutch button on the shift handle. The signal state of the clutch button changes from low to high. The transmission controller senses the signal change and controls the FL clutch valve and the L clutch valve to close. The transmission system loses driving force and the speed drops. During this process, the signal of the clutch button is always in a high level state. The driver moves the shift handle to change the mechanical gear, and releases the clutch button after completion. The signal state of the clutch button changes from high to low. The transmission controller senses the signal change and controls the FL clutch valve and L clutch valve to work. The transmission system speed stops decreasing and then increases, and the speed rises to the previous speed.

9. A four-speed power shift tractor transmission control method according to claim 5, characterized in that: The specific contents of the foot-operated clutch control are as follows: The tractor is working in the forward F1 gear. The driver presses the clutch pedal, and the signal of the clutch pedal changes from low to high. The transmission controller senses the signal change and controls the FL clutch valve and the L clutch valve to close. The transmission system loses driving force and the speed drops. During this process, the clutch pedal signal is always in a high level state. The driver turns the shift handle to change the mechanical gear, and releases the clutch pedal after completion; the clutch pedal signal changes from high to low, the speed cable controller senses the signal change, controls the FL clutch valve and the L clutch valve to work, the transmission system speed stops decreasing and rises rapidly, and the speed rises back to the previous speed.

10. A four-speed power shift tractor transmission control method according to claim 5, characterized in that: The specific contents of the foot-operated clutch and semi-clutch control are as follows: The tractor is working in the forward F1 gear. The driver presses the clutch pedal, and the clutch pedal signal changes from low to high. At this time, the speed change cable controller senses the signal change and controls the FL clutch valve and the L clutch valve to close. The transmission system loses power and the speed drops until it reaches zero. The driver slowly releases the clutch pedal, and the clutch pedal signal slowly increases. At this time, the transmission controller controls the drive current of the FL clutch valve and the L clutch valve according to the position proportion of the current signal of the clutch pedal in the entire signal interval. The drive torque of the transmission system gradually increases, and the speed gradually rises. When the speed reaches the required value, the clutch pedal is stabilized at the current position, the transmission controller controls the driving current of the FL clutch valve and the L clutch valve to remain stable, the clutch transmission maintains a stable speed difference state, the transmission system maintains low-speed transmission, and the speed is stabilized at the current lower speed; Exit semi-clutch operation, release the clutch pedal completely, the signal of the clutch pedal becomes the lowest, the transmission controller drives the FL clutch valve and the L clutch valve to work, the transmission system speed continues to increase, and the speed rises to the previous speed.

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