A hybrid powertrain system and control method for a hybrid power tractor

Abstract

The present invention provides a hybrid powertrain system for a hybrid tractor, comprising an engine, a generator and auxiliary motor, a power battery, and a differential assembly, including a drive motor, a single planetary gear assembly, clutches C1, C2, and C3. The single planetary gear ring is connected to the engine, and clutch C2 is used to selectively connect the single planetary gear ring to the engine output shaft. The drive motor is connected to the power battery, and clutch C3 is used to selectively connect the drive motor output shaft to the single planetary gear sun gear. The output shaft of the single planetary gear carrier is a PTO output shaft assembly. By selectively engaging clutches C1, C2, and C3, different gear ratios are provided between the drive motor and / or the engine and the PTO output shaft assembly. The present invention can improve the accuracy of power distribution, maintain the engine operating in a high-efficiency range, and enhance traction efficiency and fuel economy.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural machinery and vehicles, and in particular to a hybrid power assembly system for a hybrid power tractor and a control method thereof. Background Art

[0002] As an important power source for agricultural machinery, tractors can be used in conjunction with specific agricultural implements to complete different forms of field operations. Their operating modes and operating environments are complex and changeable.

[0003] Currently, the majority of tractors in my country are traditional fuel-powered tractors. During PTO operation, the uncertainty of PTO and travel system loads can cause the engine's operating point to deviate from its high-efficiency range, resulting in low traction efficiency, poor fuel economy, and severe emissions. With the increasing maturity of new energy vehicle applications, and considering the range limitations of new energy vehicles, hybrid-electric tractors have become a key development direction for the tractor industry to address these challenges.

[0004] The transmission system, a key technology in hybrid tractors, plays a decisive role in improving the tractor's overall performance. Existing transmission systems typically utilize fixed-ratio gear pairs or single planetary gears, which lack a wide speed range. This results in limited speed ranges and poor adaptability to agricultural implements. Existing PTO shaft output assemblies are typically directly connected to the engine, making the PTO shaft's output power uncontrollable and unable to maintain the engine's high-efficiency range for extended periods. Summary of the Invention

[0005] To address the shortcomings of the existing technology, the present invention provides a hybrid powertrain system for a hybrid tractor and its control method. This system utilizes a controller to control the clutch to achieve multiple operating modes, offering reliable operation, multi-mode switching, low energy consumption, and low emissions. The engine and dual motors serve as the power source for the travel system and PTO output, improving power distribution accuracy and maintaining the engine in a high-efficiency range, thereby enhancing traction efficiency and fuel economy and alleviating emissions.

[0006] The present invention achieves the above technical objectives through the following technical means.

[0007] A hybrid powertrain system for a hybrid tractor includes an engine, a generator and auxiliary motor, a power battery, and a differential assembly. The power battery is connected to the generator and auxiliary motor. A transmission system is provided between the generator and auxiliary motor and / or the engine and the differential assembly. The transmission system includes a plurality of clutch assemblies and brake assemblies for forming transmission paths with different transmission ratios between the generator and auxiliary motor and / or the engine and the differential assembly.

[0008] It also includes a drive motor, a single planetary gear assembly, a clutch C1, a clutch C2 and a clutch C3; the single planetary gear assembly includes a single planetary ring gear, a single planetary sun gear and a single planetary carrier; the single planetary ring gear, the single planetary sun gear and the single planetary carrier constitute a planetary gear train, the single planetary ring gear is connected to the engine, and the clutch C2 is used to selectively connect the single planetary ring gear to the engine output shaft for common rotation; the drive motor is connected to the power battery, and the clutch C3 is used to selectively connect the drive motor output shaft to the single planetary sun gear for common rotation; the output shaft of the single planetary carrier is a PTO output shaft assembly; the clutch C1 is used to selectively connect the engine to the generator and auxiliary motor, so as to enable the generator and auxiliary motor to generate electricity;

[0009] By selectively engaging clutch C1 , clutch C2 , and clutch C3 , different gear ratios are provided between the drive motor and / or the engine and the PTO output shaft assembly.

[0010] Furthermore, by selectively controlling the engagement of clutch C1, clutch C2 and clutch C3, a transmission mode is provided between the drive motor and / or engine and the PTO output shaft assembly: PTO pure electric transmission mode, PTO extended-range transmission mode, PTO engine direct drive transmission mode, and PTO combined drive transmission mode.

[0011] Furthermore, by selectively controlling the engagement of clutch C3, a PTO pure electric transmission mode is provided between the drive motor and the PTO output shaft assembly. The output power of the drive motor is sequentially transmitted to the PTO output shaft assembly through the drive motor output shaft assembly, clutch C3, and single planetary gear planet carrier.

[0012] Furthermore, by selectively controlling the engagement of clutch C1 and clutch C3, a PTO extended-range transmission mode is provided between the drive motor and the PTO output shaft assembly. The engine drives the generator and auxiliary motor to generate electricity through clutch C1, and the electricity generated by the generator and auxiliary motor is input into the power battery for charging; the power battery supplies power to the drive motor, and the output power of the drive motor is output through the PTO output shaft assembly.

[0013] Furthermore, by selectively controlling the engagement of clutch C2, a PTO engine direct drive transmission mode is provided between the engine and the PTO output shaft assembly, wherein the engine output power is sequentially transmitted to the PTO output shaft assembly output via the single planetary gear ring, clutch C2, and single planetary gear carrier.

[0014] Furthermore, by selectively controlling the engagement of clutch C2 and clutch C3, a PTO joint drive transmission mode is provided between the engine, drive motor and PTO output shaft assembly; the engine output power is transmitted to the single planetary gear ring and clutch C2 to the single planetary gear carrier; the drive motor output power is transmitted to the single planetary gear carrier via the drive motor output shaft assembly, clutch C3, and the single planetary gear sun gear; the two powers are transmitted to the PTO output shaft assembly for output after converging at the single planetary gear carrier.

[0015] A control method for a hybrid powertrain system of a hybrid tractor comprises the following steps:

[0016] The driver's requested driving torque T is obtained by the sensor req and the driver's requested braking torque T br ; Determine the PTO required speed V PTO ;

[0017] Transmission modes with different gear ratios between the generator and auxiliary motor and / or the engine and differential assembly: pure electric transmission mode for the traveling system, extended-range transmission mode for the traveling system, direct-drive transmission mode for the traveling system, energy recovery mode, combined drive mode for the traveling system, and power generation mode for the traveling system;

[0018] During the tractor startup phase, if the power battery state of charge (SOC) is greater than the starting threshold of the extended range transmission mode, the power battery state of charge (SOC) switch , and the driver requests a drive torque T req >0, when PTO speed demand V PTO >0, the controller makes the hybrid powertrain system power output travel system pure electric transmission mode and PTO pure electric transmission mode; when the PTO speed demand V PTO <0, the controller makes the hybrid powertrain system power output pure electric transmission mode of the running system; if the power battery state of charge SOC < running system extended range transmission mode starting threshold state of charge SOC switch And satisfy the power battery state of charge SOC < power battery starting threshold state of charge SOC L , and the driver requests a drive torque T req >0, when PTO speed demand V PTO >0, the controller makes the hybrid powertrain system power output travel system extended range transmission mode and PTO extended range transmission mode; when the PTO speed demand V PTO When <0, the controller enables the hybrid powertrain system to output the power of the running system to the extended-range transmission mode;

[0019] During the tractor driving phase, if the power battery state of charge SOC> power battery starting threshold state of charge SOC L, the controller enables the engine in the hybrid powertrain system to intervene; if the driver requests a driving torque T req > Maximum torque threshold T for efficient engine operation max , when PTO speed requirement V PTO >0, the controller enables the hybrid powertrain system to output the travel system combined drive transmission mode and the PTO combined drive mode. When the PTO speed demand V PTO <0, the controller makes the hybrid powertrain system power output walking system joint drive transmission mode; if the engine runs efficiently, the minimum torque threshold T min <Driver requested driving torque T req <Maximum torque threshold T for efficient engine operation max , when PTO speed requirement V PTO >0, the controller makes the hybrid powertrain system power output the walking system engine direct drive transmission mode and the PTO engine direct drive mode. When the PTO speed demand V PTO <0, the controller makes the hybrid powertrain system power output running system engine direct drive transmission mode; if the driver requests the driving torque T req <Minimum torque threshold T for efficient engine operation min , when PTO speed requirement V PTO >0, the controller makes the hybrid powertrain system power output travel system driving power generation transmission mode and PTO engine direct drive transmission mode, when the PTO speed demand V PTO When <0, the controller makes the hybrid powertrain system power output running system driving power generation transmission mode;

[0020] During the tractor braking phase, if the driver requests a braking torque T br >0, the controller enables the hybrid powertrain system to enter the power output energy braking recovery transmission mode.

[0021] The beneficial effects of the present invention are:

[0022] The hybrid powertrain system and control method for a hybrid tractor described in this invention utilizes a controller to control a clutch to achieve multiple operating modes, offering advantages such as reliable operation, multi-mode switching, low energy consumption, and low emissions. The engine and dual motors serve as the power sources for the travel system and PTO output, improving power distribution accuracy and maintaining the engine in a high-efficiency range. This enhances traction efficiency and fuel economy, while also alleviating emissions. During tractor operation, the system automatically switches operating modes based on operational needs, significantly reducing the operator's operational workload and improving driving efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. The drawings described below are some embodiments of the present invention. For ordinary technicians in this field, it is obvious that other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 This is a schematic diagram of the hybrid powertrain system for a hybrid tractor according to the present invention.

[0025] Figure 2 This is the power transmission roadmap for the walking system's pure electric working mode.

[0026] Figure 3 This is the power transmission roadmap for the extended-range working mode of the walking system.

[0027] Figure 4 This is the power transmission route map for the first gear working mode of the walking system engine direct drive low speed section.

[0028] Figure 5 This is the power transmission route map for the second gear working mode of the direct-drive low-speed section of the walking system engine.

[0029] Figure 6 This is the power transmission route map for the three-speed working mode of the direct-drive low-speed section of the walking system engine.

[0030] Figure 7 This is the power transmission roadmap for the first gear working mode of the direct-drive high-speed section of the walking system engine.

[0031] Figure 8 It is the power transmission roadmap of the walking system joint drive low-speed first gear working mode.

[0032] Figure 9 The power transmission route map for the first gear working mode of the low-speed section of the traveling system generator.

[0033] Figure 10 This is the power transmission roadmap for energy braking recovery working mode.

[0034] Figure 11 This is the power transmission roadmap for the PTO pure electric working mode.

[0035] Figure 12 This is the power transmission roadmap for the PTO extended-range working mode.

[0036] Figure 13 This is the power transmission roadmap for the PTO engine direct drive working mode.

[0037] Figure 14 It is the power transmission roadmap of PTO combined drive working mode.

[0038] Figure 15 This is a schematic diagram of the control system of the hybrid powertrain system for a hybrid power tractor according to the present invention.

[0039] Figure 16 This is a logic flow chart of the control strategy of the hybrid powertrain system for a hybrid tractor according to the present invention.

[0040] In the picture:

[0041] 1-Engine; 2-Generator and auxiliary motor; 3-Drive motor; 4-Power battery; 5-Clutch C1; 6-Clutch C2; 7-Clutch C3; 8-Clutch C4; 9-Brake B1; 10-Brake B2; 11-Synchronizer S; 12-Single planetary gear assembly; 13-Single planetary ring gear; 14-Single planetary sun gear; 15-Single planetary carrier; 16-Left planetary gear assembly; 17-Left planetary carrier; 18-Left planetary sun gear; 19-Left planetary ring gear; 20-Right planetary gear assembly ;21-right planetary gear carrier;22-right planetary gear ring;23-right planetary gear sun gear;24-connecting gear assembly;25-generator and auxiliary motor output gear assembly;26-low speed section gear assembly;27-high speed section gear assembly;28-main reducer gear assembly;29-differential assembly;100-generator and auxiliary motor output shaft assembly;101-engine input shaft assembly;102-engine input shaft assembly;103-drive motor output shaft assembly;104-PTO output shaft assembly;105-total output shaft assembly. DETAILED DESCRIPTION

[0042] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0043] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0044] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "axial", "radial", "vertical", "horizontal", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0045] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0046] like Figure 1 As shown, the hybrid powertrain system for a hybrid power tractor according to the present invention includes an engine 1, a generator and auxiliary motor 2, a power battery 4 and a differential assembly 29. The power battery 4 is connected to the generator and auxiliary motor 2. A transmission system is provided between the generator and auxiliary motor 2 and / or the engine 1 and the differential assembly 29. The transmission system is provided with a plurality of clutch assemblies and brake assemblies for forming transmission paths with different transmission ratios between the generator and auxiliary motor 2 and / or the engine 1 and the differential assembly 29.

[0047] The engine 1 is connected to the connecting gear assembly 24 via the engine input two-shaft assembly 101; the connecting gear assembly 24 is connected to the generator and auxiliary motor 2, and the clutch C1 5 is used to selectively connect the engine 1 to the generator and auxiliary motor 2 to enable the generator and auxiliary motor 2 to generate electricity; the engine 1 is connected to the shifting device via the engine input one-shaft assembly 101; the generator and auxiliary motor 2 is connected to the shifting device via the generator and auxiliary motor output gear assembly 25; the brake B1 is used to selectively connect the generator and auxiliary motor output shaft assembly 100 to a fixed part;

[0048] The shifting device includes a low-speed gear assembly 26, a high-speed gear assembly 27, a synchronizer S11, a left planetary gear assembly 16, a right planetary gear assembly 20, a clutch C1 5, a clutch C4 8, a brake B1 9, a brake B2 10, a final reducer gear assembly 28, and a differential assembly 29; the low-speed gear assembly 26 and the high-speed gear assembly 27 are connected to the engine 1 via the engine input shaft assembly 101; the synchronizer S11 is used to selectively connect the low-speed gear assembly 26 or the high-speed gear assembly 27 between the engine input shaft assembly 101 and the left planetary gear carrier 17. The left planetary gear assembly 16 includes a left planetary gear ring 19, a left planetary gear sun gear 18, and a left planetary gear carrier 17; the left planetary gear ring 19, the left planetary gear sun gear 18, and the left planetary gear carrier 17 constitute a planetary gear train; the right planetary gear assembly 20 includes a right planetary gear ring 22, a right planetary gear sun gear 23, and a right planetary gear carrier 21; the right planetary gear ring 22, the right planetary gear sun gear 23, and the right planetary gear carrier 21 constitute a planetary gear train; the left planetary gear ring 19 is connected to the right planetary gear carrier 21; the clutch C4 8 is used to selectively connect the left planetary gear sun gear 18 to the right planetary gear sun gear 23 for common rotation; the brake B2 10 is used to selectively connect the left planetary gear ring 19 to a fixed part; the left planetary gear ring 19 is connected to the generator and auxiliary motor output shaft assembly 100 through the generator and auxiliary motor output gear assembly 25; the right planetary gear ring 22 is connected to the total output shaft assembly 105, and the total output shaft assembly 105 is connected to the differential assembly 29 through the main reducer gear assembly 28.

[0049] The present invention also includes a drive motor 3, a single planetary gear assembly 12, a clutch C15, a clutch C26 and a clutch C37; the single planetary gear assembly 12 includes a single planetary ring gear 13, a single planetary sun gear 14 and a single planetary carrier 15; the single planetary ring gear 13, the single planetary sun gear 14 and the single planetary carrier 15 constitute a planetary gear train, the single planetary ring gear 13 is connected to the engine 1, and the clutch C26 is used to selectively connect the single planetary ring gear 13 to the output shaft of the engine 1 for common rotation; the drive motor 3 is connected to the power battery 4, and the clutch C37 is used to selectively connect the output shaft of the drive motor 3 to the single planetary sun gear 14 for common rotation; the output shaft of the single planetary carrier 15 is a PTO output shaft assembly 104; the clutch C15 is used to selectively connect the engine 1 to the power generation and auxiliary motor 2, so as to enable the power generation and auxiliary motor 2 to generate electricity;

[0050] By selectively engaging the clutch C15 , the clutch C26 and the clutch C37 , different transmission ratios are provided between the drive motor 3 and / or the engine 1 and the PTO output shaft assembly 104 .

[0051] The present invention can realize the switching of the hybrid tractor's travel system and PTO multi-mode by engaging different clutches and brakes. The engagement status of the actuators of each travel system mode is shown in Table 1, and the engagement status of the actuators of each PTO mode is shown in Table 2.

[0052] Table 1 Engagement status of the travel system mode switching element

[0053]

[0054]

[0055] Table 2 PTO mode switching element engagement status

[0056]

[0057] Note: ● represents the engagement of the clutch or brake, ○ represents the disengagement of the clutch or brake.

[0058] The hybrid powertrain system power output operating modes include: pure electric operating mode for the traveling system, extended range operating mode for the traveling system, direct engine drive operating mode for the traveling system, hybrid operating mode for the traveling system, energy braking recovery mode, pure electric operating mode for the PTO, extended range operating mode for the PTO, direct engine drive operating mode for the PTO, and combined drive operating mode for the PTO; the hybrid operating modes for the traveling system include combined drive mode for the traveling system and driving power generation mode for the traveling system; the PTO operating mode outputs power in accordance with the driving system operating mode according to the driver's needs;

[0059] like Figure 2 As shown, the travel system is in pure electric operation mode: only the brake B2 10 is engaged, the engine is in an inoperative state, the power battery 4 supplies power to the generator and auxiliary motor 2, and the output power of the generator and auxiliary motor 2 is transmitted to the differential assembly 29 through the generator and auxiliary motor output shaft assembly 100, the generator and auxiliary motor connecting gear assembly 25, the right planetary gear carrier 21, the right planetary gear ring 22, the main output shaft assembly 105, and the final reducer gear assembly 28 for output;

[0060] like Figure 3As shown, the extended-range working mode of the running system is as follows: the clutch C1 5 and the brake B2 10 are engaged, the power output by the engine 1 is transmitted through the engine input shaft assembly 101, the connecting gear assembly 24, the clutch C1 5, and the generator and auxiliary motor output shaft assembly 100 to drive the generator and auxiliary motor 2 to generate electricity. The electric power generated by the generator and auxiliary motor 2 is used to charge the power battery 4 or directly output power. The power output by the generator and auxiliary motor 2 is transmitted through the generator and auxiliary motor output shaft assembly 100, the generator and auxiliary motor connecting gear assembly 25, the right planetary gear carrier 21, the right planetary gear ring 22, the total output shaft assembly 105, and the final reducer gear assembly 28 to the differential assembly 29 for output;

[0061] The walking system engine direct drive working mode is divided into a walking system engine direct drive low speed section first gear working mode, a walking system engine direct drive low speed section second gear working mode, a walking system engine direct drive low speed section third gear working mode, a walking system engine direct drive high speed section first gear working mode, a walking system engine direct drive high speed section second gear working mode, and a walking system engine direct drive high speed section third gear working mode;

[0062] like Figure 4 As shown, the running system is in the engine direct drive low-speed first gear working mode: the clutch C4 8, the brake B1 9 and the brake B2 10 are engaged, and the synchronizer S11 is engaged to the left, the generator and the auxiliary drive motor are in the non-operating state, and the output power of the engine 1 is transmitted to the differential assembly 29 through the engine input shaft assembly 101, the low-speed gear assembly 26, the left planetary gear carrier 17, the left planetary gear sun gear 18, the clutch C4 8, the right planetary gear sun gear 23, the right planetary gear ring 22, the total output shaft assembly 105, and the final reducer gear assembly 28 for output;

[0063] like Figure 5 As shown, the running system is in the engine direct drive low-speed second gear working mode: only the brake B1 9 is engaged, and the synchronizer S11 is engaged to the left, the generator and auxiliary drive motor are in an inoperative state, and the output power of the engine 1 is transmitted to the differential assembly 29 through the engine input shaft assembly 101, the low-speed gear assembly 26, the left planetary gear carrier 17, the left planetary gear ring 19, the right planetary gear carrier 21, the right planetary gear ring 22, the main output shaft assembly 105, and the final reducer gear assembly 28 for output;

[0064] like Figure 6As shown, the running system is in the engine direct drive low-speed third gear working mode: the clutch C4 8 and the control brake B19 are engaged, and the synchronizer S11 is engaged to the left, the generator and the auxiliary drive motor are in an inoperative state, and the output power of the engine 1 is transmitted to the left planetary gear carrier 17 through the engine input shaft assembly 101 and the low-speed gear assembly 26 and is split at the left planetary gear carrier 17. One power path is transmitted to the right planetary gear ring 22 through the left planetary gear sun gear 18, the clutch C4 8, and the right planetary gear sun gear 23; the other power path is transmitted to the right planetary gear ring 22 through the left planetary gear ring 19 and the right planetary gear carrier 21; the two powers are combined at the right planetary gear ring 22 and transmitted to the differential assembly 29 for output through the total output shaft assembly 105 and the final reducer gear assembly 28;

[0065] like Figure 7 As shown, the running system is in the engine direct drive high-speed section first gear working mode, the clutch C4 8, the brake B1 9 and the brake B2 10 are engaged, and the synchronizer S11 is engaged to the right. The generator and auxiliary drive motor are in an inoperative state. The output power of the engine 1 is transmitted to the differential assembly 29 for output via the engine input first shaft assembly 101, the high-speed section gear assembly 26, the left planetary gear carrier 17, the left planetary gear sun gear 18, the clutch C4 8, the right planetary gear sun gear 23, the right planetary gear ring 22, the total output shaft assembly 105, and the final reducer gear assembly 28.

[0066] Travel system engine direct drive high-speed section second gear working mode: engage brake B1 9, and synchronizer S11 right engage, the generator and auxiliary drive motor are in the non-operating state, the output power of the engine 1 is transmitted to the differential assembly 29 through the engine input shaft assembly 101, the high-speed section gear assembly 26, the left planetary gear carrier 17, the left planetary gear ring 19, the right planetary gear carrier 21, the right planetary gear ring 22, the main output shaft assembly 105, and the final reducer gear assembly 28 for output;

[0067] The third gear working mode of the direct-drive high-speed section of the traveling system engine is as follows: the clutch C4 8 and the brake B19 are engaged, and the synchronizer S11 is engaged to the right. The generator and auxiliary drive motors are in an inoperative state. The output power of the engine 1 is transmitted to the left planetary gear carrier 17 through the engine input shaft assembly 101 and the high-speed section gear assembly 26 and is split at the left planetary gear carrier 17. One power path is transmitted to the right planetary gear ring 22 through the left planetary gear sun gear 18, the clutch C4 8, and the right planetary gear sun gear 23; the other power path is transmitted to the right planetary gear ring 22 through the left planetary gear ring 19 and the right planetary gear carrier 21. After the two powers converge at the right planetary gear ring 22, they are transmitted to the differential assembly 29 for output through the total output shaft assembly 105 and the final reducer gear assembly 28.

[0068] like Figure 8As shown, the running system is in the low-speed first gear working mode: the clutch C4 8 and the brake B2 10 are engaged, and the synchronizer S11 is engaged to the left. The output power of the engine 1 is transmitted to the right planetary gear ring 22 via the engine input shaft assembly 101, the low-speed gear assembly 26, the left planetary gear carrier 17, the left planetary gear sun gear 18, the clutch C48, and the right planetary gear sun gear 23; the power of the generator and auxiliary drive motor 2 is transmitted to the right planetary gear ring 22 via the generator and auxiliary drive motor output shaft assembly 100, the generator and auxiliary drive motor output gear assembly 25, and the right planetary gear carrier 21; the two powers converge at the right planetary gear ring 22 and are transmitted to the differential assembly 29 for output via the total output shaft assembly 105 and the final reducer gear assembly 28;

[0069] The travel system is jointly driven in the low-speed second gear working mode, with only the synchronizer S11 left engaged.

[0070] The travel system is jointly driven in the low-speed third gear working mode, clutch C4 8 is engaged, and synchronizer S11 is engaged to the left.

[0071] Travel system combined drive high-speed section first gear working mode: engage clutch C4 8 and control brake B2 10, and synchronizer S11 is engaged right.

[0072] Travel system combined drive high-speed section second gear working mode: only synchronizer S11 right is engaged.

[0073] Travel system combined drive high-speed section third gear working mode: engage clutch C4 8, and synchronizer S11 right engage.

[0074] The traveling system driving power generation working mode is divided into the traveling system driving power generation low speed section first gear working mode, the traveling system driving power generation low speed section second gear working mode, the traveling system driving power generation low speed section third gear working mode, the traveling system driving power generation high speed section first gear working mode, the traveling system driving power generation high speed section second gear working mode and the traveling system driving power generation high speed section third gear working mode;

[0075] like Figure 9As shown, the travel system is in the first gear working mode of the low-speed driving generator stage, the clutch C4 8 and the brake B2 10 are engaged, and the synchronizer S11 is engaged to the left. The output power of the engine 1 is transmitted through the engine input shaft assembly 101, the low-speed stage gear assembly 26, the left planetary gear carrier 17, the left planetary gear sun gear 18, the clutch C4 8, and the right planetary gear sun gear 23 to the right planetary gear ring 22 for diversion; one path of power is transmitted through the right planetary gear sun gear 23, the right planetary gear ring 22, the total output shaft assembly 105, and the final reducer gear assembly 28 to the differential assembly 29 for output; one path of power is transmitted through the right planetary gear carrier 21, the generator and auxiliary motor output gear assembly 25, and the generator and auxiliary motor output shaft assembly 100 to drive the generator and auxiliary motor 2 to generate electricity. The electric power generated by the generator and auxiliary motor 2 is used to charge the power battery 4.

[0076] Second gear working mode of low speed section of traveling system driving generator: only synchronizer S11 left is engaged.

[0077] Travel system driving generator low speed section third gear working mode: engage clutch C4 8, and synchronizer S11 left engaged.

[0078] Travel system combined drive high-speed section first gear working mode: engage clutch C4 8 and control brake B2 10, and synchronizer S11 is engaged right.

[0079] Travel system combined drive high-speed section second gear working mode: only synchronizer S11 right is engaged.

[0080] Travel system combined drive high-speed section third gear working mode: engage clutch C4 8, and synchronizer S11 right engage.

[0081] like Figure 10 As shown, in the energy recovery braking mode: the brake B210 is engaged, the engine is in an inoperative state, and during the braking process, the differential assembly 29 recovers the power during the braking process and drives the generator and auxiliary motor 2 to generate electricity through the main reducer gear assembly 28, the main output shaft assembly 105, the right planetary gear ring 22, the right planetary gear carrier 21, the generator and auxiliary motor connecting gear assembly 25, and the generator and auxiliary motor output shaft assembly 100. The electric power generated by the generator and auxiliary motor 2 is used to charge the power battery 4;

[0082] like Figure 11 As shown, the PTO pure electric working mode: the clutch C37 is engaged, the engine is in an inoperative state, and the output power of the drive motor 3 is transmitted to the PTO output shaft assembly 104 through the drive motor output shaft assembly 103, the clutch C37, and the single planetary gear planet carrier 15 for output;

[0083] like Figure 12As shown, in the PTO range-extending working mode, the clutch C15 and the clutch C37 are engaged, and the output power of the engine 1 is input through the engine shaft assembly 101, the connecting gear assembly 24, and the clutch C15 to drive the generator and the auxiliary drive motor 2 to generate electricity. The electric power generated by the generator and the auxiliary drive motor is used to charge the power battery 4, and the power battery supplies power to the drive motor 3. The output power of the drive motor 3 is transmitted to the PTO output shaft assembly 104 for output through the drive motor output shaft assembly 103, the clutch C37, the single planetary gear sun gear 14, and the single planetary gear planet carrier 15;

[0084] like Figure 13 As shown, the PTO engine direct drive working mode: the clutch C2 6 is engaged, the drive motor is in an inoperative state, and the output power of the engine 1 is transmitted to the PTO output shaft assembly 104 through the engine input two-shaft assembly 102, the single planetary gear ring 13, the clutch C26, and the single planetary gear carrier 15;

[0085] like Figure 14 As shown, in the PTO combined drive working mode: clutch C2 6 and clutch C3 7 are engaged, and the output power of the engine 1 is transmitted to the single planetary gear ring 13 through the engine input two-shaft assembly 102, the single planetary gear ring 13, and the clutch C26 to the single planetary gear carrier 15; the output power of the drive motor 3 is transmitted to the single planetary gear carrier 15 through the drive motor output shaft assembly 103, the clutch C37, and the single planetary gear sun gear 14; the two powers are combined at the single planetary gear carrier 15 and then transmitted to the PTO output shaft assembly 104 for output;

[0086] like Figure 15 The control system principle diagram shown in the figure shows the control system principle of the hybrid powertrain system for a hybrid tractor according to the present invention, which includes the following steps:

[0087] Step 1: Information collection.

[0088] The data interaction management layer collects the working status information of each assembly of the current hybrid powertrain system, the driver's intention information, and the tractor operating condition information. The driver's intention information includes the driver's requested driving torque T req , Driver requested braking torque T br and PTO required speed V PTO ;

[0089] Step 2: Information data analysis,

[0090] The data interaction management layer identifies the working status information of each assembly of the hybrid powertrain system, the driver's intention information, and the vehicle's operating condition information, and parses it into driving torque information, braking torque information, PTO required speed, clutch status information, control brake status information, synchronizer status information, engine working status, drive motor working status, and battery working status. The data interaction management layer sends the parsed information to the vehicle control strategy layer;

[0091] Step 3: Execute the power output working mode.

[0092] The vehicle control strategy layer analyzes and calculates the received information to determine the power output working mode of the hybrid powertrain system, and issues a working mode execution command to the actuator control layer. The actuator control layer controls each assembly of the hybrid powertrain system to complete the corresponding working command according to the working mode execution command, and feeds back information on whether the working command is completed to the actuator control layer, so that the hybrid powertrain system realizes the power output of the corresponding working mode. The working command includes the engine 1 control command, the drive motor 2 control command, the power battery control command 4, the clutch C15 control command, the clutch C26 control command, the clutch C37 control command, the clutch C48 control command, the brake B19 control command, the brake B210 control command, the synchronizer command 9 power generation and the auxiliary drive motor 3 control command;

[0093] Step 4: Work order execution verification,

[0094] Whether the actuator has completed the corresponding command is determined based on the actuator status feedback information. If the corresponding command has not been completed, the command is sent to the actuator control layer based on the feedback signal until the actuator completes the command;

[0095] like Figure 16 As shown, the control method of the hybrid powertrain system for a hybrid power tractor according to the present invention comprises the following steps:

[0096] The driver's requested driving torque T is obtained by the sensor req and the driver's requested braking torque T br ; Determine the PTO required speed V PTO ;

[0097] Transmission modes with different transmission ratios between the power generation and auxiliary motor (2) and / or the engine (1) and the differential assembly (29): a pure electric transmission mode for the walking system, an extended-range transmission mode for the walking system, a direct-drive transmission mode for the walking system engine, an energy recovery braking mode, a combined driving mode for the walking system, and a power generation mode for the walking system;

[0098] During the tractor startup phase, if the power battery state of charge (SOC) is greater than the starting threshold of the extended range transmission mode, the power battery state of charge (SOC) switch , and the driver requests a drive torque T req >0, when PTO speed demand V PTO >0, the controller makes the hybrid powertrain system power output travel system pure electric transmission mode and PTO pure electric transmission mode; when the PTO speed demand V PTO <0, the controller makes the hybrid powertrain system power output pure electric transmission mode of the running system; if the power battery state of charge SOC < running system extended range transmission mode starting threshold state of charge SOC switch And satisfy the power battery state of charge SOC < power battery starting threshold state of charge SOC L , and the driver requests a drive torque T req >0, when PTO speed demand V PTO >0, the controller makes the hybrid powertrain system power output travel system extended range transmission mode and PTO extended range transmission mode; when the PTO speed demand V PTO When <0, the controller enables the hybrid powertrain system to output the power of the running system to the extended-range transmission mode;

[0099] During the tractor driving phase, if the power battery state of charge SOC> power battery starting threshold state of charge SOC L , the controller enables the engine in the hybrid powertrain system to intervene; if the driver requests a driving torque T req > Maximum torque threshold T for efficient engine operation max , when PTO speed requirement V PTO >0, the controller enables the hybrid powertrain system to output the travel system combined drive transmission mode and the PTO combined drive mode. When the PTO speed demand V PTO <0, the controller makes the hybrid powertrain system power output walking system joint drive transmission mode; if the engine runs efficiently, the minimum torque threshold T min <Driver requested driving torque T req <Maximum torque threshold T for efficient engine operation max , when PTO speed requirement V PTO >0, the controller makes the hybrid powertrain system power output the walking system engine direct drive transmission mode and the PTO engine direct drive mode. When the PTO speed demand V PTO <0, the controller makes the hybrid powertrain system power output running system engine direct drive transmission mode; if the driver requests the driving torque T req Minimum torque threshold T for efficient engine operation min , when PTO speed requirement VPTO >0, the controller makes the hybrid powertrain system power output travel system driving power generation transmission mode and PTO engine direct drive transmission mode, when the PTO speed demand V PTO When <0, the controller makes the hybrid powertrain system power output running system driving power generation transmission mode;

[0100] During the tractor braking phase, if the driver requests a braking torque T br >0, the controller enables the hybrid powertrain system to enter the power output energy braking recovery transmission mode.

[0101] It can be seen from the above control strategy logic that the hybrid powertrain system for a hybrid power tractor according to the present invention can select whether to output the PTO according to demand, and switch to the working mode of the PTO according to the working mode of the walking system, which is suitable for the complex working conditions of the tractor. The reverse gear in the present invention can be achieved by reversing the motor.

[0102] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0103] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent embodiments or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for controlling a hybrid powertrain system for a hybrid tractor, wherein the hybrid powertrain system for the hybrid tractor comprises an engine, a generator and auxiliary motor, a power battery, and a differential assembly, wherein the power battery is connected to the generator and auxiliary motor, and a transmission system is provided between the generator and auxiliary motor, the engine, and the differential assembly, wherein the transmission system comprises a plurality of clutch assemblies and brake assemblies; It is characterized by: It also includes a drive motor, a single planetary gear assembly, a clutch C1, a clutch C2 and a clutch C3; the single planetary gear assembly includes a single planetary ring gear, a single planetary sun gear and a single planetary carrier; the single planetary ring gear, the single planetary sun gear and the single planetary carrier constitute a planetary gear train, the single planetary ring gear is connected to the engine, and the clutch C2 is used to selectively connect the single planetary ring gear to the engine output shaft for common rotation; the drive motor is connected to the power battery, and the clutch C3 is used to selectively connect the drive motor output shaft to the single planetary sun gear for common rotation; the output shaft of the single planetary carrier is a PTO output shaft assembly; the clutch C1 is used to selectively connect the engine to the generator and auxiliary motor, so as to enable the generator and auxiliary motor to generate electricity; The control method comprises the following steps: The driver's requested driving torque T is obtained by the sensor req and the driver's requested braking torque T br ; Determine the PTO required speed V PTO ; Transmission modes with different gear ratios between the power generation and auxiliary motors, the engine, and the differential assembly: pure electric transmission mode for the traveling system, extended-range transmission mode for the traveling system, direct engine drive mode for the traveling system, energy recovery mode, combined drive mode for the traveling system, and power generation mode for the traveling system; During the tractor startup phase, if the power battery state of charge (SOC) is greater than the starting threshold of the extended range transmission mode, the power battery state of charge (SOC) switch , and the driver requests a driving torque T req >0, when PTO speed demand V PTO >0, the controller makes the hybrid powertrain system power output travel system pure electric transmission mode and PTO pure electric transmission mode; when the PTO speed demand V PTO <0, the controller makes the hybrid powertrain system power output pure electric transmission mode of the running system; if the power battery state of charge SOC < running system extended range transmission mode starting threshold state of charge SOC switch And the power battery state of charge SOC < power battery starting threshold state of charge SOC L , and the driver requests a driving torque T req >0, when PTO speed demand V PTO >0, the controller makes the hybrid powertrain system power output travel system extended range transmission mode and PTO extended range transmission mode; when the PTO speed demand V PTO When <0, the controller enables the hybrid powertrain system to output the power of the running system to the extended-range transmission mode; During the tractor driving phase, if the power battery state of charge SOC> power battery starting threshold state of charge SOC L , the controller causes the engine in the hybrid powertrain system to intervene in operation; If the driver requests a driving torque T req > Maximum torque threshold T for efficient engine operation max , when PTO speed requirement V PTO >0, the controller enables the hybrid powertrain system to output the travel system combined drive transmission mode and the PTO combined drive mode. When the PTO speed demand V PTO <0, the controller makes the hybrid powertrain system power output walking system joint drive transmission mode; if the engine runs efficiently, the minimum torque threshold T min <Driver requested driving torque T req <Maximum torque threshold T for efficient engine operation max , when PTO speed requirement V PTO >0, the controller makes the hybrid powertrain system power output the walking system engine direct drive transmission mode and the PTO engine direct drive mode. When the PTO speed demand V PTO When <0, the controller sets the hybrid powertrain system power output running system engine direct drive transmission mode; If the driver requests a driving torque T req <Minimum torque threshold T for efficient engine operation min , when PTO speed requirement V PTO >0, the controller makes the hybrid powertrain system power output travel system driving power generation transmission mode and PTO engine direct drive transmission mode, when the PTO speed demand V PTO When <0, the controller makes the hybrid powertrain system power output running system driving power generation transmission mode; During the tractor braking phase, if the driver requests a braking torque T br >0, the controller enables the hybrid powertrain system to enter the power output energy braking recovery transmission mode.

2. The hybrid powertrain system for a hybrid tractor according to claim 1, characterized in that: By selectively controlling the engagement of clutch C1, clutch C2 and clutch C3, a transmission mode is provided between the drive motor, engine and PTO output shaft assembly: PTO pure electric transmission mode, PTO extended-range transmission mode, PTO engine direct drive transmission mode, and PTO combined drive transmission mode.

3. The hybrid powertrain system for a hybrid tractor according to claim 2, characterized in that: By selectively controlling the engagement of clutch C3, a PTO pure electric transmission mode is provided between the drive motor and the PTO output shaft assembly. The output power of the drive motor is transmitted to the PTO output shaft assembly through the drive motor output shaft assembly, clutch C3, and single planetary gear planet carrier in sequence.

4. The hybrid powertrain system for a hybrid tractor according to claim 2, characterized in that: By selectively controlling the engagement of clutch C1 and clutch C3, a PTO extended-range transmission mode is provided between the drive motor and the PTO output shaft assembly. The engine drives the generator and auxiliary motor to generate electricity through clutch C1, and the electricity generated by the generator and auxiliary motor is input into the power battery for charging; the power battery supplies power to the drive motor, and the output power of the drive motor is output through the PTO output shaft assembly.

5. The hybrid powertrain system for a hybrid tractor according to claim 2, characterized in that: By selectively controlling the engagement of clutch C2, a PTO engine direct drive transmission mode is provided between the engine and the PTO output shaft assembly, and the engine output power is transmitted to the PTO output shaft assembly output in sequence through the single planetary gear ring, clutch C2, and single planetary gear carrier.

6. The hybrid powertrain system for a hybrid tractor according to claim 2, characterized in that: By selectively controlling the engagement of clutch C2 and clutch C3, a PTO joint drive transmission mode is provided between the engine, drive motor and PTO output shaft assembly; the engine output power is transmitted to the single planetary gear ring and clutch C2 to the single planetary gear carrier; the drive motor output power is transmitted to the single planetary gear carrier via the drive motor output shaft assembly, clutch C3 and the single planetary gear sun gear; the two powers are transmitted to the PTO output shaft assembly for output after converging at the single planetary gear carrier.

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