Tractor hybrid power assembly and control method thereof

Abstract

The application discloses a tractor hybrid power assembly and a control method thereof, and relates to the technical field of power transmission, wherein the hybrid power assembly comprises an engine, a generator connected with the engine, a driving motor, an output shaft used for transmitting power to a driving axle, a first mechanical transmission chain configured to transmit power of the engine to the output shaft, a second mechanical transmission chain configured to transmit power of the driving motor to the output shaft, and a first gear shifting device configured to selectively switch the first mechanical transmission chain between an engaged state and a separated state, so that the power assembly is switched between an engine direct drive parallel mode and a series electric drive mode. The hybrid power assembly of the application integrates a switchable engine direct drive path and a motor drive path, optimizes power transmission modes according to working conditions, solves the problem that the series hybrid power transmission has a relatively low efficiency under some working conditions, and improves the overall energy efficiency of the power assembly.

Description

Technical Field

[0001] This application relates to the field of power transmission technology, and in particular to a tractor hybrid powertrain and its control method. Background Technology

[0002] Traditional power shift tractors cannot decouple engine speed from vehicle speed, resulting in poor fuel economy, frequent gear shifting, high labor intensity, and reliance on imported key components, posing a risk of being held hostage by technology bottlenecks.

[0003] Series hybrid power configurations are commonly used in related technologies, where all the engine's power is used to drive a generator to produce electricity. The generated electrical energy is either stored in a battery or directly supplied to the drive motor to propel the vehicle. While this configuration can decouple the engine's operating point from the vehicle's driving state, its energy transfer path is relatively simple. All energy used for propulsion must undergo two energy conversion processes: mechanical energy to electrical energy and then back to mechanical energy.

[0004] However, the two energy conversion processes mentioned above inevitably introduce additional energy losses, which limits the overall transmission efficiency of this configuration in commonly used tractor operating conditions, especially when the engine could operate efficiently to directly drive the vehicle. Summary of the Invention

[0005] This application aims to at least partially solve one of the technical problems in the related art. To this end, the first objective of this application is to propose a tractor hybrid powertrain. By configuring a first mechanical transmission chain and a second mechanical transmission chain, and setting a first shifting device that can selectively switch the state of the first mechanical transmission chain, the system achieves switching between a direct mechanical drive parallel mode and a series electric drive mode. Under high-efficiency engine operating conditions, the first mechanical transmission chain can be engaged, allowing engine power to be directly mechanically transmitted to the output shaft. This avoids the energy conversion losses inherent in the series path, which involve two energy conversions (power generation and electric drive), thereby effectively improving the overall efficiency of the transmission system. Under conditions requiring speed decoupling or low load, the system can switch to a series electric drive mode, retaining the flexibility and control advantages of electric drive.

[0006] To achieve the above objectives, a first aspect of this application provides a tractor hybrid powertrain, comprising: an engine; a generator connected to the engine; a drive motor; an output shaft for transmitting power to a drive axle; a first mechanical transmission chain configured to transmit power from the engine to the output shaft; a second mechanical transmission chain configured to transmit power from the drive motor to the output shaft; and a first shifting device configured to selectively switch the first mechanical transmission chain between an engaged state and a disengaged state, thereby switching the powertrain between an engine direct-drive parallel mode and a series electric drive mode.

[0007] According to the tractor hybrid powertrain of the present application embodiment, by configuring a first mechanical transmission chain and a second mechanical transmission chain, and setting a first shifting device that can selectively switch the state of the first mechanical transmission chain, the switching between the engine mechanical direct drive parallel mode and the series electric drive mode is realized. Under the high-efficiency condition of the engine, the first mechanical transmission chain can be engaged to directly mechanically transmit the engine power to the output shaft, avoiding the energy conversion loss of two times in the series path, thereby effectively improving the overall efficiency of the transmission system. Under the condition that speed decoupling or low load is required, it can be switched to the series electric drive mode, retaining the flexibility and control advantages of electric drive.

[0008] In some embodiments of this application, the first shifting device is located at the intersection of the power input of the engine and the drive motor.

[0009] In some embodiments of this application, the first mechanical transmission chain includes: an engine drive shaft that passes through the input shaft of a drive motor, and the input shaft of the drive motor is a hollow shaft.

[0010] In some embodiments of this application, the first mechanical transmission chain further includes: at least two empty gears with different gear positions, the empty gears being loosely fitted on the output shaft, wherein the at least two empty gears with different gear positions are respectively in constant mesh with corresponding drive gears fixedly connected to the engine transmission shaft.

[0011] In some embodiments of this application, the first mechanical transmission chain further includes a second shifting device for selectively coupling either of the idler gears to the output shaft.

[0012] In some embodiments of this application, the second mechanical transmission chain includes: a drive motor output shaft, which is rigidly connected to at least one fixed-gear drive motor drive gear, wherein the at least one fixed-gear drive motor drive gear transmits power to at least one corresponding driven gear through gear meshing, and the driven gear is loosely fitted on the output shaft.

[0013] In some embodiments of this application, the second mechanical transmission chain further includes a third shifting device for selectively coupling either driven gear to the output shaft.

[0014] In some embodiments of this application, the aforementioned tractor hybrid powertrain further includes: a front axle drive mechanism, which includes a front axle drive gear disposed on the output shaft, a front axle driven gear meshing with the front axle drive gear and loosely fitted on the front axle drive shaft, and a fourth shifting device for selectively coupling the front axle driven gear to the front axle drive shaft; and a power output device, which is directly connected to the engine's power output drive shaft.

[0015] To achieve the above objectives, a second aspect of this application proposes a control method for a tractor hybrid powertrain, comprising: acquiring vehicle operating condition information; controlling a first shifting device to operate based on the vehicle operating condition information; when the vehicle operating condition information indicates a high-efficiency direct drive condition, controlling the first shifting device to engage a first mechanical transmission chain, thereby enabling the powertrain to operate in an engine mechanical direct drive parallel mode; when the vehicle operating condition information indicates a condition requiring speed decoupling or a low-load condition, controlling the first shifting device to disengage the first mechanical transmission chain, enabling the engine to drive a generator to generate electricity, and controlling the drive motor to drive the output shaft through a second mechanical transmission chain, thereby enabling the powertrain to operate in a series electric drive mode.

[0016] In some embodiments of this application, the control method of the tractor hybrid powertrain described above further includes: determining the high-efficiency direct drive condition when the vehicle speed is within a preset high-efficiency engine operating range; and determining the condition requiring speed decoupling or low load condition when the vehicle is in a starting, reversing, or PTO operation state.

[0017] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a tractor hybrid powertrain according to some embodiments of this application.

[0019] Figure 2 This is a schematic diagram of the transmission path for power generation conditions according to some embodiments of this application.

[0020] Figure 3 This is a schematic diagram of the transmission path in pure electric drive mode according to some embodiments of this application.

[0021] Figure 4 This is a schematic diagram of the transmission path in pure electric drive mode according to some embodiments of this application.

[0022] Figure 5 This is a schematic diagram of the transmission path in a pure electric drive + engine direct drive PTO operating condition according to some embodiments of this application.

[0023] Figure 6 This is a schematic diagram of the transmission path in the engine direct drive + pure electric parallel drive mode according to some embodiments of this application.

[0024] Figure 7 This is a schematic diagram of the transmission path in the engine direct drive + pure electric parallel drive mode according to some embodiments of this application.

[0025] Figure 8 This is a schematic diagram of the transmission path in the engine direct drive + pure electric parallel drive mode according to some embodiments of this application.

[0026] Figure 9 This is a schematic diagram of the transmission path in the engine direct drive + pure electric parallel drive mode according to some embodiments of this application.

[0027] Figure 10 This is a flowchart of a control method for a tractor hybrid powertrain according to some embodiments of this application.

[0028] Figure label: 1. Engine; 2. Generator; 3. Generator Controller (GCU); 4. Power Battery; 5. Motor Controller (MCU); 6. Drive Motor; 7. Drive Motor 2nd Gear Drive Gear; 8. Drive Motor 1st Gear Drive Gear; 9. Engine 2nd Gear Drive Gear; 10. Engine 3rd Gear Drive Gear; 11. Engine Drive Shaft; 12. Power Take-Off (PTO) Output Shaft; 14. Engine 3rd Gear Driven Gear; 15. Second Gear Shifter; 16. Engine 2nd Gear Driven Gear; 17. Drive Motor 1st Gear Driven Gear; 18. Third Gear Shifter; 19. Drive Motor 2nd Gear Driven Gear; 20. Front Axle Drive Gear; 21. Fourth Gear Shifter; 22. Front Axle Drive Shaft; 23. Front Axle Driven Gear; 24. Front Axle; 25. Rear Axle; 26. Input Shaft; 27. Detailed Implementation The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0029] As mentioned in the background section, hybrid power technology is considered an important technological direction for achieving energy conservation and emission reduction, improving operational efficiency, and adapting to the integration of renewable energy. In related technologies, a series hybrid power configuration is often used to achieve these objectives. This configuration includes an engine, a generator, a drive motor, and a battery. The engine drives the generator to produce electricity. The generated electrical energy is converted into power and either directly drives the motor or is stored in the battery. The drive motor then transmits power to the drive axle through a reduction gear mechanism. This design effectively decouples engine speed from vehicle speed, allowing the engine to operate relatively independently in its high-efficiency range, while also simplifying the mechanical transmission structure.

[0030] However, when the above-mentioned solution is applied to long-term, heavy-load field operations or highway transport of tractors that require continuous high power output, the inherent, single electric drive path design inevitably introduces two energy conversion losses (mechanical energy - electrical energy - mechanical energy) to achieve the flexibility advantage of decoupling the engine speed from the drive wheels, thus impairing the overall transmission efficiency of the system. For example, within the tractor's commonly used operating speed range, the engine could efficiently drive the wheels directly through mechanical transmission, but in the series configuration, all power must be converted into electrical energy and then output through the electric motor, resulting in unnecessary energy loss. The overall vehicle economy cannot meet the increasingly stringent energy efficiency requirements.

[0031] Through in-depth analysis, the applicant discovered that the series configuration lacks a controllable mechanical path that leads directly from the engine to the drive axle, making it impossible to bypass the generator and electric drive components under high-efficiency operating conditions. Furthermore, the lack of a switchable integrated design between the mechanical direct drive path and the electric drive path results in a rigid system topology, making it impossible to dynamically select the optimal energy flow mode based on real-time operating conditions.

[0032] To address the aforementioned issues, this application proposes a tractor hybrid powertrain. By integrating independent engine mechanical transmission chains and drive motor mechanical transmission chains into the powertrain and configuring a switchable switching device, the power flow topology of the system is reconstructed. This effectively improves energy transfer efficiency under high-efficiency direct drive conditions without affecting the speed decoupling and flexible control advantages of the series mode.

[0033] The following description, with reference to the accompanying drawings, illustrates the tractor hybrid powertrain and its control method according to embodiments of this application.

[0034] Figure 1 This is a schematic diagram of a tractor hybrid powertrain according to some embodiments of this application.

[0035] like Figure 1 As shown, the tractor hybrid powertrain of this application embodiment may include: an engine 1, a generator 2, a drive motor 6, an output shaft 14, a first mechanical transmission chain, a second mechanical transmission chain, and a first shifting device 9.

[0036] In this configuration, generator 2 is connected to engine 1. Output shaft 14 transmits power to the drive axle. A first mechanical transmission chain is configured to transmit power from engine 1 to output shaft 14. A second mechanical transmission chain is configured to transmit power from drive motor 6 to output shaft 14. A first shifting device 9 is configured to selectively switch the first mechanical transmission chain between an engaged state and a disengaged state, thereby switching the powertrain between an engine direct-drive parallel mode and a series electric drive mode.

[0037] Specifically, engine 1, as one of the main power sources of the hybrid system, functions to output mechanical torque, which can be used to drive generator 2 to generate electricity, or directly participate in vehicle driving under certain operating conditions. Generator 2 is connected to engine 1 and is usually arranged coaxially with engine 1. It is used to generate electricity by rotating under the drive of engine 1, converting mechanical energy into electrical energy. Drive motor 6, as another power source, is used to consume electrical energy to output mechanical torque to drive the vehicle, or in certain modes, it operates as generator 2 to achieve regenerative braking. Output shaft 14 is the final torque output component of the powertrain, used to transmit power to the drive axle, and its rotation directly determines the vehicle's speed.

[0038] The first mechanical transmission chain transmits power from engine 1 to output shaft 14. This transmission chain constitutes the physical channel for direct engine drive. The second mechanical transmission chain transmits power from drive motor 6 to output shaft 14. This transmission chain constitutes the physical channel for electric drive. The first shifting device 9 selectively switches the first mechanical transmission chain between a mechanically engaged state and a mechanically disengaged state. By controlling the engagement and disengagement of the first shifting device 9, it can be determined whether the power of engine 1 can be transmitted to the output shaft via a mechanical path, thereby enabling the entire powertrain to switch between engine mechanical direct drive parallel mode and series electric drive mode.

[0039] It should be noted that the first mechanical transmission chain refers to any mechanical transmission mechanism configured to transmit the power of engine 1 to the output shaft. For example, it may include, but is not limited to, a transmission path consisting of gears, shafts, and clutches, wherein the engine power directly drives the output shaft after gear shifting. In a specific embodiment, this transmission chain includes an engine drive shaft, a driving gear, a driven gear, and a shifting device to achieve multiple direct-drive gears.

[0040] The second mechanical transmission chain refers to any mechanical transmission mechanism configured to transmit power from the drive motor 6 to the output shaft. For example, it may include, but is not limited to, a transmission path consisting of a motor output shaft, a gear set, and a shifting device, wherein motor power is transmitted to the output shaft via fixed or variable gears. In a specific embodiment, this transmission chain includes a drive motor output shaft, a driving gear, a driven gear, and a shifting device to provide pure electric drive or auxiliary drive.

[0041] The direct-drive parallel mode refers to the engine 1 directly driving the output shaft via a mechanical transmission chain, while the drive motor can selectively assist in driving via another mechanical transmission chain, forming a parallel power output. For example, this may include, but is not limited to, the engine and drive motor jointly providing torque to the drive axle to improve transmission efficiency. In this mode, the engine typically operates within its efficient operating range, and the drive motor can compensate for power during gear shifts.

[0042] The series electric drive mode refers to the engine driving generator 2 to generate electricity, which supplies the drive motor 6. The drive motor 6 drives the output shaft through a mechanical transmission chain, while there is no direct mechanical connection between the engine 1 and the output shaft. This mode can be used, for example, during starting, reversing, or PTO operations, to decouple engine speed from vehicle speed. In this mode, energy is converted through power generation and electric conversion, making it suitable for low-load conditions or situations requiring speed decoupling.

[0043] Thus, dual-mode switching is achieved through the first shifting device 9. When the first shifting device 9 is disengaged, the mechanical connection between engine 1 and drive axle is severed, and all the power of engine 1 is used for power generation. The system operates in series electric drive mode, which offers the advantage of speed decoupling. When the first shifting device 9 is engaged, the power of engine 1 can directly drive the wheels through a mechanical path, while drive motor 6 can also output power in parallel. The system operates in parallel mode, achieving higher transmission efficiency under high-efficiency conditions. The synergy of these two mechanisms allows the system to dynamically select the most energy-efficient power transmission path based on real-time operating conditions, thereby jointly solving the problem of low transmission efficiency in series configurations under certain operating conditions mentioned in the background art.

[0044] To further optimize the reliability, smoothness, and management efficiency of the mode switching device in the above embodiments, in some embodiments of this application, such as Figure 1 As shown, the first shifting device 9 can be a clutch, and the first shifting device 9 is located at the intersection of the power input of the engine 1 and the drive motor 6.

[0045] Specifically, see Figure 1 As shown, the power of engine 1 is output through drive shaft 12, and the power of drive motor 6 is output through input shaft 27. A first shifting device 9 is arranged between drive shaft 12 and input shaft 27. When the first shifting device 9 is engaged, drive shaft 1 and input shaft 27 are locked, allowing engine power to flow to input shaft 27 and be transmitted to subsequent transmission gears via the first shifting device 9. When the first shifting device 9 is disengaged, drive shaft 1 and input shaft 27 can rotate independently, cutting off the path of engine power transmission to subsequent transmission gears. By adopting the above arrangement, and by clearly distinguishing the power flow origins in series and parallel modes with a single clutch, the problems of power coupling and mode switching are simultaneously solved. The structure is compact, reducing the number of transmission components and axial space occupation.

[0046] It should be noted that the first switching device 9 can be a clutch, such as a dry clutch or a wet clutch. To further improve durability and smoothness during frequent switching under harsh working conditions, tractor operating conditions may involve frequent switching and heat dissipation requirements. Furthermore, wet clutches, being immersed in lubricating oil, offer better heat dissipation, longer lifespan, and are more suitable for conditions involving frequent engagement and slippage. Therefore, a wet clutch is preferred. The wet clutch cools the friction plates with oil, enabling it to withstand higher thermal loads and providing more stable shifting quality. It is particularly suitable for scenarios involving sudden load changes and frequent mode switching that tractors may encounter during field operations.

[0047] In order to further compactly arrange the input shaft system of engine 1 and drive motor 6, so as to save space and ensure transmission rigidity, in some embodiments of this application, the first mechanical transmission chain includes: engine drive shaft 12, engine drive shaft 12 passing through the input shaft of drive motor 6, and the input shaft 27 of drive motor 6 is a hollow shaft.

[0048] Specifically, see Figure 1 As shown, the input shaft 27 of the drive motor 6 is constructed as a hollow shaft. The engine drive shaft 12 passes through the interior of the input shaft 27. One end of the engine drive shaft 12 connects to the engine 1 and the generator 2, and the other end is equipped with the drive gear required for direct engine drive. The rotor of the drive motor 6 is fixedly connected to the input shaft 27. The coaxial through-type design allows for a high degree of axial integration of the power input of the engine and the drive motor 6, reducing the number of parts and the overall size.

[0049] It should be noted that the input shaft of the drive motor 6 is not limited to a hollow structure. Provided sufficient torsional strength is ensured, its wall thickness and material can be designed according to torque requirements. Bearings need to be installed between the engine drive shaft 12 and the input shaft 27 to ensure that they can rotate independently.

[0050] In order to provide multiple fixed speed ratios on the engine mechanical direct drive path to optimize the working efficiency of engine 1 under different vehicle speeds and loads and expand the operating range of efficient direct drive, in some embodiments of this application, the first mechanical transmission chain further includes: at least two empty gears with different gear positions, the empty gears being loosely fitted on the output shaft 14, wherein the at least two empty gears with different gear positions are respectively constantly meshed with corresponding drive gears fixedly connected to the engine drive shaft.

[0051] Specifically, see Figure 1The output shaft 14 is fitted with a 3rd gear driven gear 15 and a 2nd gear driven gear 17. These two gears are connected to the output shaft 14 via bearings and can rotate relative to each other. The 2nd gear drive gear 10 and the 3rd gear drive gear 11 are fixedly mounted on the through-drive engine drive shaft 12. The 2nd gear drive gear 10 is constantly meshed with the 2nd gear driven gear 17, and the 3rd gear drive gear 11 is constantly meshed with the 3rd gear driven gear 15, forming two direct-drive gear pairs with different transmission ratios. By adopting the above-mentioned 2nd gear design with at least two gears, multiple transmission ratios are provided for direct-drive engine operation, enabling multiple high-efficiency operating points for the engine. This allows the engine speed to be adjusted to the high-efficiency range at different vehicle speeds. For example, the optimal gear can be matched for different operating speeds (such as low-speed heavy load and high-speed transfer), improving the average fuel economy in direct-drive mode.

[0052] In order to enable the selection of different gears, in some embodiments of this application, the first mechanical transmission chain further includes: a second shifting device 16, for selectively coupling any idler gear with the output shaft 14.

[0053] Specifically, such as Figure 1 As shown, the second shifting device 16 is mounted on the output shaft 14, located between the engine's 3rd gear driven gear 15 and the engine's 2nd gear driven gear 17. The second shifting device 16 can move to the left to couple with the engaging gear ring of the engine's 2nd gear driven gear 17, locking the engine's 2nd gear driven gear 17 onto the shaft 14; it can also move to the right to couple with the engaging gear ring of the engine's 3rd gear driven gear 15, locking the engine's 3rd gear driven gear 15 onto the shaft 14; when in the intermediate position, both gears are disengaged from the output shaft 14. Therefore, by controlling the position of the second shifting device 16, either the engine's direct drive 2nd or 3rd gear can be selected. It is understood that the specific structure of the second shifting device 16 can be a slip clutch. The number of gears can be increased as needed, correspondingly increasing the number of neutral gears and coupling positions in the shifting device.

[0054] In order to optimize the power output of the drive motor so that it can also work at a suitable speed ratio and provide auxiliary power to the vehicle or ensure smooth shifting when necessary, in some embodiments of this application, the second mechanical transmission chain may include: a drive motor output shaft 27, which is rigidly connected to at least one fixed gear drive motor drive gear, wherein the at least one fixed gear drive motor drive gear transmits power to at least one corresponding driven gear through gear meshing, and the driven gear is loosely fitted on the output shaft 27.

[0055] In some embodiments of this application, the second mechanical transmission chain further includes a third shifting device 19 for selectively coupling any driven gear with the output shaft 27. The third shifting device 19 may be a meshing sleeve.

[0056] Specifically, refer to Figure 1 As shown, the drive motor output shaft 27 is fixedly mounted with the drive motor first gear 8 and the drive motor second gear 7. The torque and speed of the drive motor 6 are directly reflected in these two gears, so that the torque of the drive motor is amplified by the fixed drive gears and then transmitted to the subsequent transmission mechanism.

[0057] The driven gear 18 of the first gear of the drive motor is constantly meshed with the driving gear 8 of the drive motor, and the driven gear 20 of the second gear of the drive motor is constantly meshed with the driving gear 7. The driven gears 18 and 20 are loosely fitted onto the output shaft 14. A third shifting device 19 is disposed on the output shaft 14 and is used to selectively lock either the driven gear 18 or the driven gear 20 of the second gear of the drive motor onto the output shaft 14. For example, when the vehicle requires high torque and low speed, the driven gear 18 of the first gear of the drive motor (motor first gear) can be engaged; when the vehicle requires high speed, the driven gear 20 of the second gear of the drive motor (motor second gear) can be engaged. By adopting the above design, the drive motor 6 also has gear selection capability, which can better adapt to different operating conditions. For example, when the engine 1 is shifting gears, the drive motor 6 can be fixedly engaged in first gear to provide continuous power; when driving at high speed in pure electric mode, it can switch to second gear to reduce the motor speed and improve efficiency.

[0058] Furthermore, the number of gears and gear ratios of the drive motor 6 can be designed independently from the engine gears. The shifting devices (second and third shifting devices) of the two are mechanically independent, but are coordinated and controlled by the vehicle controller. In some implementations, the drive motor 6 can be equipped with more than two gears to further optimize efficiency.

[0059] In order to extend the four-wheel drive function on the basis of the hybrid powertrain to adapt to the complex field operations and slippery road conditions of the tractor, in some embodiments of this application, the above-mentioned tractor hybrid powertrain further includes: a front axle drive mechanism, which includes a front axle drive gear 21 disposed on the output shaft, a front axle driven gear 24 meshing with the front axle drive gear 21 and loosely fitted on the front axle drive shaft 23, and a fourth shifting device 22 for selectively coupling the front axle driven gear 24 to the front axle drive shaft 23.

[0060] Specifically, refer to Figure 1As shown, a front axle drive gear 21 is fixedly mounted on the output shaft 14. A front axle driven gear 24 is loosely fitted on the front axle drive shaft 23, and the front axle driven gear 24 is constantly meshed with the front axle drive gear 21. A fourth shifting device 22 is provided on the front axle drive shaft 23 to lock or disengage the loosely fitted front axle driven gear 24 from the front axle drive shaft 23. When the fourth shifting device 22 is engaged, power is transmitted from the output shaft 14 through the front axle drive gear 21 and the front axle driven gear 24 to the front axle drive shaft 23, ultimately driving the front axle 25. When the fourth shifting device 22 is disengaged, the front axle driven gear 24 idles, and power only drives the rear axle 26.

[0061] Therefore, the power extraction point for front axle drive is set on the output shaft, which is the endpoint of power convergence. Engagement and disengagement of the front axle are controlled by an independent fourth shifter. The structure is clear, requiring no changes to the core hybrid powertrain; power is only split at the output, enabling flexible switching between rear-wheel drive and four-wheel drive modes. When front axle drive is not needed, the clutch can be disengaged, avoiding parasitic losses caused by dragging the front axle drivetrain.

[0062] It should be noted that the four-wheel drive mechanism can work in conjunction with any of the gear combinations of the aforementioned engine or drive motor. That is, regardless of whether it is in pure electric mode, parallel direct drive mode or series mode, as long as the system has power output to the output shaft 14, it can engage the front axle drive as needed.

[0063] To ensure that the engine can still independently provide power to the implements mounted on the tractor in non-direct drive mode (such as series power generation mode), in some embodiments of this application, the above-mentioned tractor hybrid powertrain further includes: a power output device 13, which is directly connected to the power output drive shaft 12 of the engine 1.

[0064] Specifically, such as Figure 1 As shown, the power take-off (PTO) device 13 is directly connected to the drive shaft 12 of the engine 1. When the engine 1 is running, the PTO device 13 receives power and outputs at a standard speed (e.g., 540 rpm or 1000 rpm). The operation of the PTO device 13 is only related to the start / stop and speed of the engine, and is completely decoupled from the vehicle's driving state (vehicle speed, drive mode). This eliminates the need for a separate drive motor 6 or a complex power take-off mechanism for the PTO, reducing cost and complexity. For example, in pure electric driving + PTO operation mode, the engine 1 drives the generator 2 to generate electricity and power the PTO device 13, while the drive motor 6 independently drives the vehicle. The two are coordinated in terms of energy by the control system. By directly connecting the PTO device 13 to the engine drive shaft 12, the independence and reliability of the PTO power source are achieved.

[0065] It should be noted that the power take-off (PTO) device 13 may include a clutch to control the engagement and disengagement of power. Its connection point can be any suitable location on the drive shaft 12, preferably at a location with stable shaft support. For example, combining this PTO integration solution with the aforementioned four-wheel drive mechanism and multi-gear design constitutes a fully functional and efficient high-horsepower hybrid tractor assembly.

[0066] In some embodiments of this application, the mechanical energy of engine 1 is converted into electrical energy and then driven by an electric motor, and the whole is divided into two parts: power generation and driving.

[0067] Specifically, the transmission path of the power generation condition is as follows: Figure 2 As shown, engine 1 drives generator 2 to generate electricity. Generator 2 converts AC power into DC power through GCU 3 (Generator Control Unit) and stores it in power battery 4. MCU 5 (Motor Control Unit) converts the DC power in power battery 4 into AC power and drives motor 6 according to the load control.

[0068] In some embodiments, the driving conditions include three modes: pure electric drive, pure electric drive + engine direct drive (PTO), and engine direct drive + pure electric parallel drive. The switching between the three modes is achieved through the cooperation of the first shifting device 9, the second shifting device 16, the third shifting device 19, and the fourth shifting device 22.

[0069] Specifically, the first shifting device 9 is used to control the coupling or disengagement of the drive motor output shaft 27 and the power output transmission shaft 12 of the engine 1, realizing the switching between series and direct-drive gears; the second shifting device 16 is used to control the coupling or disengagement of the engine 3rd gear driven gear 15 and the engine 2nd gear driven gear 17 with the output shaft 14, realizing the switching between different gears of direct-drive; the third shifting device 19 is used to control the coupling or disengagement of the drive motor 1st gear driven gear 18 and the drive motor 2nd gear driven gear 20 with the output shaft 14, realizing the switching between different gears of pure electric; the fourth shifting device 22 is used to control the coupling and disengagement of the front axle driven gear 24 and the front axle transmission shaft 23, realizing the switching between front-drive. Among them, the drive motor gears in the pure electric drive mode include gear 1 and gear 2; the drive motor gears in the pure electric drive + engine direct drive PTO mode include gear 1 and gear 2; the engine gears in the engine direct drive + pure electric parallel drive mode include gear 1, gear 2, gear 3 and gear 4; and the drive motor gears include gear 1 and gear 2. The relationship between each gear and the shifting device is shown in Table 1 below.

[0070] Table 1 In some embodiments, when the driving condition is pure electric drive mode, the transmission path when the drive motor is in gear 1 is as follows: Figure 3 As shown, the first shifting device 9 is disengaged, and the third shifting device 19 engages with the first gear driven gear 18 of the drive motor. The power transmission path is: drive motor 6 → input shaft 27 → first gear driving gear 8 of the drive motor → first gear driven gear 18 of the drive motor → third shifting device 19 → output shaft 14 → rear axle 26, thus achieving rear axle drive. If the fourth shifting mechanism 22 is coupled, the power transmission path is: output shaft 14 → front axle driving gear 21 → front axle driven gear 24 → fourth shifting device 22 → front axle drive shaft 23 → front axle 25, thus simultaneously achieving front axle drive.

[0071] The transmission path when the drive motor is in gear 2 is as follows Figure 4 As shown, the first shifting device 9 is disengaged, and the third shifting device 19 engages with the second-gear driven gear 20 of the drive motor. The power transmission path is: drive motor 6 → input shaft 27 → second-gear driving gear 7 of the drive motor → second-gear driven gear 20 of the drive motor → third shifting device 19 → output shaft 14 → rear axle 26, thus achieving rear axle drive. If the fourth shifting mechanism 22 is coupled, the power transmission path is: output shaft 14 → front axle driving gear 21 → front axle driven gear 24 → fourth shifting device 22 → front axle drive shaft 23 → front axle 25, thus simultaneously achieving front axle drive.

[0072] In some embodiments, when the driving condition is pure electric drive + engine direct drive PTO, the power transmission path of the pure electric gear is the same as in the above embodiments, such as... Figure 5 As shown, taking the drive motor with gear 1 as an example, the first shifting device 9 is disengaged, and the third shifting device 19 engages with the drive motor's gear 18 driven in gear 1. The power transmission path is: drive motor 6 → input shaft 27 → drive motor gear 1 driving gear 8 → drive motor gear 1 driven gear 18 → third shifting device 19 → output shaft 14 → rear axle 26, realizing rear axle drive. The engine directly drives the PTO, and the PTO power transmission path is: engine 1 → generator 2 → engine drive shaft 12 → power output device 13 (PTO). While the engine drives the PTO, it needs to generate electricity simultaneously to provide the electrical energy required by the drive motor.

[0073] In some embodiments, when the driving condition is engine direct drive + pure electric parallel drive, engine 1 and drive motor 6 drive in parallel, and the power transmission path of the pure electric gear is the same as described in the pure electric drive working mode above. The engine includes 4 gears, as follows: Engine 1st gear: such as Figure 6As shown, the first shifting device 9 engages, and the third shifting device 19 engages with the drive motor's first-gear driven gear 18. At this time, the drive motor is in first gear, and the power transmission path is: drive motor 6 → input shaft 27 → drive motor first-gear drive gear 8 → drive motor first-gear driven gear 18 → third shifting device 19 → output shaft 14 → rear axle 26, achieving rear axle drive. The engine power transmission path is: engine 1 → engine drive shaft 12 → first shifting device 9 → drive motor first-gear drive gear 8 → drive motor first-gear driven gear 18 → third shifting device 19 → output shaft 14 → rear axle 26. If the fourth shifting device 22 is coupled, the power transmission path is: output shaft 14 → front axle drive gear 21 → front axle driven gear 24 → fourth shifting device 22 → front axle drive shaft 23 → front axle 25, simultaneously achieving front axle drive.

[0074] Engine 2nd gear: such as Figure 7 As shown, the first shifting device 9 is disengaged, the third shifting device 19 engages with the drive motor's first-gear driven gear 18, and the second shifting device 16 engages with the engine's second-gear driven gear 17. At this time, the drive motor is in first gear, and the power transmission path is: drive motor 6 → input shaft 27 → drive motor first-gear drive gear 8 → drive motor first-gear driven gear 18 → third shifting device 19 → output shaft 14 → rear axle 26, achieving rear axle drive. The engine power transmission path is: engine 1 → engine drive shaft 12 → engine second-gear drive gear 10 → engine second-gear driven gear 17 → second shifting device 16 → output shaft 14 → rear axle 26. If the fourth shifting device 22 is coupled, the power transmission path is: output shaft 14 → front axle drive gear 21 → front axle driven gear 24 → fourth shifting device 22 → front axle drive shaft 23 → front axle 25, simultaneously achieving front axle drive.

[0075] Engine 3rd gear: such as Figure 8 As shown, the first shifting device 9 is disengaged, the third shifting device 19 engages with the drive motor's first-gear driven gear 18, and the second shifting device 16 engages with the engine's third-gear driven gear 15. At this time, the drive motor is in first gear, and the power transmission path is: drive motor 6 → input shaft 27 → drive motor first-gear drive gear 8 → drive motor first-gear driven gear 18 → third shifting device 19 → output shaft 14 → rear axle 26, achieving rear axle drive. The engine power transmission path is: engine 1 → engine drive shaft 12 → engine third-gear drive gear 11 → engine third-gear driven gear 15 → second shifting device 16 → output shaft 14 → rear axle 26. If the fourth shifting device 22 is coupled, the power transmission path is: output shaft 14 → front axle drive gear 21 → front axle driven gear 24 → fourth shifting device 22 → front axle drive shaft 23 → front axle 25, simultaneously achieving front axle drive.

[0076] Engine 4 gears: such as Figure 9As shown, the first shifting device 9 is engaged, the third shifting device 19 is disengaged, and the second shifting device 16 is disengaged. At this time, the drive motor is in gear 2, and the power transmission path is: drive motor 6 → input shaft 27 → drive motor 2nd gear drive gear 7 → drive motor 2nd gear driven gear 20 → third shifting device 19 → output shaft 14 → rear axle 26, realizing rear axle drive. The engine power transmission path is: engine 1 → engine drive shaft 12 → engine 3rd gear drive gear 11 → engine 3rd gear driven gear 15 → second shifting device 16 → output shaft 14 → rear axle 26. If the fourth shifting device 22 is engaged, the power transmission path is: output shaft 14 → front axle drive gear 21 → front axle driven gear 24 → fourth shifting device 22 → front axle drive shaft 23 → front axle 25, simultaneously realizing front axle drive.

[0077] As a concrete example, when the driver presses the forward gear button, the vehicle starts moving in pure electric mode (gear 1), with engine 1 driving generator 2 to generate electricity. When the vehicle's speed reaches the range of 6km / h-20km / h, engine 1 engages to drive, and drive motor 6 gradually disengages, entering engine direct drive mode. Once fully in engine direct drive mode, drive motor 6 idles with the engine. If a heavy load is detected, drive motor 6 provides assistance to prevent the engine from stalling. In engine direct drive mode, drive motor 6 continuously provides power during gear shifts (1st to 2nd, 2nd to 3rd, 3rd to 4th), ensuring uninterrupted power. When the vehicle's speed reaches 20km / h-60km / h, engine 1 disengages from drive and switches to generator mode, driving the vehicle in pure electric mode (gear 2). When the driver presses the reverse gear button, the vehicle reverses in pure electric mode (gear 1), with engine 1 driving generator 2 to generate electricity. When the driver presses the PTO button, the vehicle moves in pure electric mode (gear 1), with engine 1 driving generator 2 to generate electricity.

[0078] It should be noted that the generator in the above embodiments can be a low-speed generator, or a high-speed motor and a set of reduction gears can replace the drive motor and generator in the above scheme.

[0079] Corresponding to the above embodiments, this application proposes a control method for a tractor hybrid powertrain.

[0080] like Figure 10 As shown, the control method for a tractor hybrid powertrain according to an embodiment of this application may include the following steps: S101, obtain vehicle operating condition information.

[0081] The vehicle operating information includes: vehicle speed, accelerator pedal opening, brake pedal signal, state of charge of the power battery, engine speed, PTO activation switch signal, and the gear or mode selected by the driver.

[0082] S102 controls the first gear shifting device to operate based on vehicle operating condition information.

[0083] S103, when the vehicle operating condition information is high-efficiency direct drive operating condition, control the first shift device to engage the first mechanical transmission chain, so that the powertrain works in the engine mechanical direct drive parallel mode.

[0084] S104, when the vehicle operating condition information is that speed decoupling or low load condition is required, the first shift device is controlled to separate the first mechanical transmission chain, so that the engine drives the generator to generate electricity, and the drive motor is controlled to drive the output shaft through the second mechanical transmission chain, so that the powertrain works in series electric drive mode.

[0085] In some embodiments of this application, the control method of the tractor hybrid powertrain described above further includes: determining the high-efficiency direct drive condition when the vehicle speed is within a preset high-efficiency engine operating range; and determining the condition requiring speed decoupling or low load condition when the vehicle is in a starting, reversing, or PTO operation state.

[0086] In a specific control example, when the driver starts the vehicle and engages drive, the controller determines it's a start-up condition. The first gear shifter disengages, and the system starts in pure electric first gear mode, with the engine only generating electricity. When the vehicle speed rises above 6 km / h and stabilizes within the range commonly used in field operations, the controller determines it has entered a high-efficiency direct drive mode. It smoothly engages the first gear shifter and adjusts the torque of the engine and drive motor, smoothly transitioning to engine-driven first gear direct drive mode. If the driver presses the PTO button, the controller immediately determines it's in PTO operating mode. Even if it's currently in direct drive mode, it may disengage the first gear shifter, switching to series mode, allowing the engine to focus on driving PTO and generating electricity, with the vehicle driven by the drive motor.

[0087] To further enhance the driving experience, especially the smoothness of gear shifting in engine direct drive mode, the control method also includes controlling the drive motor to continuously output power to the output shaft through a second mechanical transmission chain during engine gear shifting in engine mechanical direct drive parallel mode.

[0088] Specifically, when shifting from engine 1st gear to 2nd gear, the controller switches the first shifting device from engagement with the drive motor's 1st gear driven gear to engagement with the engine's 2nd gear driven gear. During the brief transition of the second shifting device, the mechanical path from the engine to the wheels is momentarily interrupted. At this time, the controller maintains the drive motor in its currently engaged gear (e.g., motor 1st gear) and outputs a certain amount of drive torque to compensate for the loss of vehicle driving force caused by the engine power interruption, thus achieving uninterrupted gear shifting. After the shift is complete, the torque distribution between the engine and drive motor is coordinated. This system is suitable for tractor field operations, ensuring stable operating speed during gear shifting and improving work quality.

[0089] As a specific example, the working process is dynamically described using a 200-horsepower tractor equipped with the hybrid powertrain of this application for seeding operations.

[0090] Before starting the operation, the driver starts the tractor. The vehicle controller completes its self-check, and the power battery is fully charged. The driver engages a forward gear and lightly presses the accelerator pedal. At this point, the vehicle speed is zero, and the controller determines that it is in a starting condition (speed decoupling is required). The controller controls the first shifting device (wet clutch) to remain disengaged and controls the third shifting device to engage the first gear driven gear of the drive motor. The drive motor draws power from the battery and transmits power to the rear axle through the first gear pair. The vehicle starts smoothly on pure electric power, the engine does not start, the environment is quiet, and there are no exhaust emissions.

[0091] The tractor enters the field and begins low-speed sowing, maintaining a stable speed of 8 km / h. The controller detects that the speed has entered the preset high-efficiency direct-drive range (6-20 km / h) and that power demand is stable. The controller determines this to be a high-efficiency direct-drive condition. The controller starts the engine and slowly engages the first gear shifter. Simultaneously, the second gear shifter is controlled to engage the engine's first-gear driven gear. The engine's power directly drives the wheels via the first-gear mechanical path, and the drive motor torque gradually decreases to zero and rotates accordingly. The system enters the engine's first-gear direct-drive parallel mode. In this mode, the engine operates at its high-efficiency point, the transmission path is a direct mechanical transmission, energy loss is small, and fuel economy is significantly better than traditional series hybrid or power-shift tractors.

[0092] During operation, the vehicle encountered a slope, causing a sudden increase in load. The controller detected that the engine load was too high, posing a risk of stalling. At this point, the controller immediately instructed the drive motor to output auxiliary torque through its engaged first-gear pair, driving the vehicle in parallel with the engine. This helped overcome resistance, preventing the engine from slowing down or stalling, and improving operational stability.

[0093] After the slope, the field road becomes longer, and the driver increases the operating speed to 15 km / h. The controller determines that the current engine speed in first gear has deviated from the optimal range and decides to upshift. The controller prepares to execute the engine shift from first to second gear. After the upshift command is issued, the controller first controls the drive motor to increase the torque output in first gear to maintain vehicle driving force. Subsequently, it controls the second shifting device to disengage from the first gear and move into the second gear. During the brief moment when the second shifting device is in neutral, engine power is interrupted, but the drive motor continues to provide power, ensuring that the vehicle speed does not fluctuate significantly. After the second shifting device successfully engages the second gear, engine power is restored, and the drive motor torque decreases accordingly. The entire process is smooth in power transition, achieving uninterrupted gear shifting. The driver hardly feels any power fluctuation, ensuring the uniformity of operation.

[0094] After the sowing operation is completed, the driver heads towards the highway for a transfer, increasing the vehicle speed to 40 km / h. The controller determines that the vehicle speed has exceeded the efficient range of engine direct drive (>20 km / h). Therefore, the controller disengages the first gear shifting device, cutting off the engine direct drive path. The engine speed is decoupled from the vehicle speed and adjusted to an efficient power generation speed, focusing on driving the generator to charge the battery. Simultaneously, the controller controls the third gear shifting device to switch to the second gear of the drive motor, allowing the drive motor to propel the vehicle at high speed with a higher gear ratio. The system switches to series electric drive mode, avoiding the high-speed, low-efficiency problems that may arise from engine direct drive during high-speed cruising.

[0095] Throughout the operation, if the driver needs to start the air pump on the PTO-driven seeder, they simply press the PTO button. The controller receives the PTO activation signal and ensures the engine runs regardless of the current driving mode. PTO power is directly obtained from the engine driveshaft and output at a constant speed. Vehicle movement is controlled by the current mode (which may be series or parallel), with neither interfering with the other, perfectly achieving independent constant speed PTO and flexible vehicle speed adjustment.

[0096] In this application scenario, compared to series hybrid systems, a highly efficient mechanical direct drive path is introduced for the predominantly low-to-medium speed operating conditions. Compared to traditional power shift tractors, continuously variable transmission (CVT) is decoupled from engine speed, reducing driver workload and eliminating power interruption during gear shifts. Furthermore, its compact design facilitates integration into existing tractor platforms, and the integration of four-wheel drive and PTO functions meets the versatility requirements of agricultural machinery.

[0097] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0098] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0099] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0100] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0101] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0102] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, use and processing of the relevant data must comply with the relevant laws, regulations and standards of the relevant countries and regions, and corresponding operation entry points are provided for users to choose to authorize or refuse.

[0103] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A tractor hybrid powertrain, characterized in that, include: engine; A generator, which is connected to the engine; Drive motor; The output shaft is used to transmit power to the drive axle; A first mechanical transmission chain is configured to transmit the power of the engine to the output shaft; The second mechanical transmission chain is configured to transmit the power of the drive motor to the output shaft; The first shifting device is configured to selectively switch the first mechanical transmission chain between an engaged state and a disengaged state, so that the powertrain can switch between an engine direct drive parallel mode and a series electric drive mode.

2. The tractor hybrid powertrain according to claim 1, characterized in that, The first shifting device is located at the intersection of the power input of the engine and the drive motor.

3. The tractor hybrid powertrain according to claim 1, characterized in that, The first mechanical transmission chain includes: An engine drive shaft passes through the input shaft of the drive motor, and the input shaft of the drive motor is a hollow shaft.

4. The tractor hybrid powertrain according to claim 3, characterized in that, The first mechanical transmission chain also includes: At least two different gear positions of the unloaded gear are loosely fitted on the output shaft, wherein the at least two different gear positions of the unloaded gear are respectively in constant mesh with the corresponding drive gear fixedly connected to the engine drive shaft.

5. The tractor hybrid powertrain according to claim 4, characterized in that, The first mechanical transmission chain also includes: The second shifting device is used to selectively couple either of the said empty gears to the output shaft.

6. The tractor hybrid powertrain according to claim 1, characterized in that, The second mechanical transmission chain includes: The drive motor output shaft is rigidly connected to at least one fixed-gear drive motor gear, wherein... The drive motor with at least one fixed gear transmits power to at least one corresponding driven gear through gear meshing, and the driven gear is loosely fitted on the output shaft.

7. The tractor hybrid powertrain according to claim 6, characterized in that, The second mechanical transmission chain also includes: A third shifting device is used to selectively couple either of the driven gears to the output shaft.

8. The tractor hybrid powertrain according to claim 1, characterized in that, Also includes: The front axle drive mechanism includes a front axle drive gear disposed on the output shaft, a front axle driven gear meshing with the front axle drive gear and loosely fitted on the front axle drive shaft, and a fourth shifting device for selectively coupling the front axle driven gear to the front axle drive shaft. A power take-off device, which is directly connected to the power take-off drive shaft of the engine.

9. A control method for a tractor hybrid powertrain as described in any one of claims 1 to 8, characterized in that, include: Obtain vehicle operating condition information; Based on the vehicle operating condition information, control the first gear shifting device to operate; When the vehicle operating condition information is high-efficiency direct drive operating condition, the first shifting device is controlled to engage the first mechanical transmission chain, so that the powertrain works in engine mechanical direct drive parallel mode. When the vehicle operating condition information indicates a need for speed decoupling or a low-load condition, the first shifting device is controlled to disconnect the first mechanical transmission chain, allowing the engine to drive the generator to generate electricity, and the drive motor is controlled to drive the output shaft through the second mechanical transmission chain, so that the powertrain operates in series electric drive mode.

10. The control method for a tractor hybrid powertrain according to claim 9, characterized in that, The method further includes: When the vehicle speed is within the preset high-efficiency engine operating range, it is determined to be a high-efficiency direct drive condition; When the vehicle is in a starting, reversing, or PTO operation state, it is determined to be a condition requiring speed decoupling or low load operation.

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