A multi-mode hybrid tractor drive system and method of controlling the same

Abstract

The application relates to a multi-mode hybrid tractor driving system and a control method thereof, and relates to the technical field of hybrid tractors, and comprises an engine, an independent PTO module, a generator, two groups of electric driving systems and a central clutch. The electric driving system comprises a motor and a coupler, the coupler utilizes a planetary array, a brake and a synchronizer to realize power confluence and distribution. The system realizes various modes such as single driving, conventional four-wheel driving, super front and rear driving and inter-axle power distribution by controlling the states of the clutches, can concentrate the power of the two motors to improve the traction force or redundantly drive when a fault occurs on one side. The PTO is directly connected with the engine to guarantee heavy load operation, and the generator optimizes the engine working condition. The application solves the problems of high emission and large energy consumption of traditional fuel vehicles and the problems of complex transmission and low efficiency of existing hybrid vehicles, realizes the organic unification of environmental protection, energy saving and intelligent control, and is particularly suitable for heavy load operation requirements under complex agricultural conditions.

Description

Technical Field

[0001] This invention relates to the field of hybrid tractor technology, and in particular to a multi-mode hybrid tractor drive system and its control method. Background Technology

[0002] Traditional gasoline-powered tractors rely solely on internal combustion engines for power. This necessitates adjusting the engine's operating point according to load variations, preventing the engine from operating stably within its economical range. Furthermore, the energy conversion process releases significant amounts of carbon dioxide, nitrogen oxides, and particulate matter, contributing to air pollution and indirectly polluting soil and water, thus disrupting the ecological balance. On the other hand, the dwindling global fossil fuel supply and increasing regional instability have led to persistently high oil prices, continuously increasing the operating costs of traditional gasoline-powered tractors and placing a growing economic burden on farmers.

[0003] Therefore, against the backdrop of achieving the "dual carbon" goal, the demand for new energy agricultural machinery and equipment in modern agricultural production is becoming increasingly urgent. New energy agricultural machinery and equipment has advantages such as low emissions, high energy utilization, and high levels of intelligence, providing a new approach for developing environmentally friendly, green, and intelligent agricultural machinery. Hybrid tractors are an important component of new energy agricultural machinery and equipment, and are also one of the high-end intelligent agricultural equipment that the country has focused on supporting in recent years.

[0004] Hybrid tractors, which coordinate the control of the internal combustion engine and electric motor, can significantly reduce fuel consumption while ensuring high power output, making it the main technological approach for high-horsepower new energy agricultural machinery. Currently, high-horsepower hybrid tractors mainly employ two technological approaches: series and parallel. Among them, parallel hybrid tractors mostly use the ECVT technology, which suffers from problems such as complex transmission structure and control strategy, increased power loss due to numerous transmission components, and lower transmission efficiency, resulting in relatively few products in the industry.

[0005] Series hybrid tractors operate on the same principle as range-extended electric vehicles, with the engine generating electricity to drive an electric motor, which in turn powers the entire machine. This technology offers advantages such as relatively simple structure and control strategies, continuous high-efficiency engine operation, and the ability to perform heavy-duty tasks like deep tillage, heavy harrowing, and ditching. However, it still faces challenges such as the single motor's power being insufficient for continuous heavy-duty operations, the need for additional transmission components to meet four-wheel drive requirements, and low transmission efficiency in four-wheel drive mode. Furthermore, existing dual-motor drive systems cannot proportionally distribute power to the tractor's front and rear axles, making it difficult to get out of trouble in complex road conditions. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the present invention discloses a multi-mode hybrid tractor drive system and its control method.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0008] A multi-mode hybrid tractor drive system and its control method include:

[0009] engine;

[0010] The PTO module is connected to the engine drivetrain.

[0011] A generator, connected to the engine drive, is used to charge the power battery pack;

[0012] The electric drive system consists of two sets, namely electric drive system a and electric drive system b, both of which are powered by a battery pack.

[0013] A central clutch is installed between the two electric drive systems;

[0014] The electric drive system includes:

[0015] Electric motor;

[0016] Coupler, used to connect to the motor drive;

[0017] Drive the clutch, which is connected to the coupler for transmission.

[0018] A drive wheel assembly is connected to a drive clutch for transmission; the drive wheel assembly of electric drive system a is the front wheel assembly, and the drive wheel assembly of electric drive system b is the rear wheel assembly.

[0019] The central clutch is connected to the coupler of electric drive system a and electric drive system b to realize the power transmission between electric drive system a and electric drive system b.

[0020] Preferably, the coupler includes:

[0021] The input gear shaft is connected at one end to the output shaft of the motor for transmission.

[0022] A planetary transmission device is connected to the other end of the input gear shaft; the output end of the planetary transmission device is connected to the drive clutch; and the ring gear of the planetary transmission device is rotatably connected to its housing.

[0023] The transmission gear shaft has teeth that mesh with the gear ring of the planetary transmission device.

[0024] The brake is installed at one end of the transmission gear shaft;

[0025] The connecting shaft is connected at one end to the central clutch drive.

[0026] A transmission gear is rotatably connected to a connecting shaft on the same axis; the transmission gear meshes with the input gear shaft.

[0027] A synchronizer, installed at the other end of the connecting shaft, is used to realize the power transmission between the connecting shaft and the transmission gear shaft or transmission gear.

[0028] Preferably, different operating modes are achieved by controlling electric drive system a, electric drive system b and central clutch, including single drive mode and dual drive mode;

[0029] The single-drive mode is divided into front-wheel drive mode and rear-wheel drive mode. In the single-drive mode, the central clutch is disengaged, and electric drive system a or electric drive system b works independently to drive the front wheel assembly to achieve front-wheel drive mode or drive the rear wheel assembly to achieve rear-wheel drive mode; or the central clutch is engaged, and the power of electric drive system b is transmitted to electric drive system a to drive the front wheel assembly to achieve front-wheel drive mode; or the power of electric drive system a is transmitted to electric drive system b to drive the rear wheel assembly to achieve rear-wheel drive mode; or electric drive system a or electric drive system b works independently to drive both the front wheel assembly and the rear wheel assembly to achieve four-wheel drive mode.

[0030] In dual-drive mode, electric drive system a and electric drive system b operate simultaneously, with the central clutch engaged. The four-drive mode includes:

[0031] In Super Front-Wheel Drive mode, electric drive system a and electric drive system b jointly drive the front wheel assembly;

[0032] In Super Rear-Wheel Drive mode, electric drive system a and electric drive system b jointly drive the rear wheel assembly;

[0033] In the front axle power distribution mode, electric drive system a drives the front wheel assembly, and electric drive system a and electric drive system b jointly drive the rear wheel assembly; by controlling the oil pressure of the drive clutch of electric drive system a, its power output is controlled, and the proportion of power from electric drive system a to the front wheel assembly is controlled.

[0034] In the rear axle power distribution mode, electric drive system b drives the rear wheel assembly, while electric drive system a and electric drive system b jointly drive the front wheel assembly. By controlling the oil pressure of the drive clutch of electric drive system b, its power output is controlled, thereby realizing the proportion of power from electric drive system b to the rear wheel assembly.

[0035] Preferably, it also includes a power control system and an electric control system;

[0036] The power control system includes an inverter electrically connected to the generator, and a battery management system, a power battery pack, and an integrated drive motor controller that are electrically and signal-connected to the inverter in sequence; the integrated drive motor controller is electrically and signal-connected to the motors of the two electric drive systems respectively.

[0037] The power control system includes a TCU, which is connected to the generator, inverter, battery management system, integrated drive motor controller, and the motors, couplers, brakes, synchronizers, and drive clutches of the two electric drive systems.

[0038] Preferably, the drive wheel assembly includes:

[0039] The main reducer is connected to the drive clutch in a transmission manner;

[0040] The differential is connected to the main reducer for transmission.

[0041] There are two drive wheels, which are respectively connected to the two output shafts of the differential.

[0042] Preferably, a wheel-side reducer is installed between the drive wheel and the differential to realize the power transmission from the differential to the drive wheel.

[0043] Preferably, the two sets of electric drive systems are arranged along the length of the tractor, and electric drive system a and electric drive system b are symmetrically arranged about the central clutch.

[0044] By employing the technical solution described above, the present invention has the following beneficial effects:

[0045] (1) This invention achieves high torque output by setting up a PTO module independent of the electric drive system, allowing it to directly obtain power from the engine. This design ensures that the agricultural implement can still work stably when the battery power is insufficient or when performing continuous high-power operations such as rotary tillage and sowing, without being limited by battery capacity. At the same time, by using a generator to convert the mechanical energy generated by the engine into electrical energy for storage, not only is the overall vehicle range extended, but the engine's operating range is also optimized, allowing it to work continuously in the high-efficiency range, thereby significantly reducing fuel consumption and emissions, and solving the problem that traditional fuel tractor engines cannot work stably in the economic range and cause serious pollution.

[0046] (2) This invention further employs two independent electric drive systems in conjunction with a central clutch and a coupler with power convergence and divergence functions to construct a variety of flexible drive modes. By controlling the state combinations of the brakes, synchronizers, drive clutches, and central clutch, the system can achieve multiple modes such as single drive (front drive / rear drive), conventional four drive, super front drive, super rear drive, and front and rear axle power distribution. In particular, in dual drive mode, the power from motors on different axles is vectorized and synthesized within the coupler using a planetary transmission device, realizing super front drive mode, super rear drive mode, front axle power distribution mode, and front axle power distribution mode. This allows for the concentrated output of dual motor power to a single axle or proportional distribution, significantly improving traction under extreme muddy or hill-climbing conditions. In addition, this structure allows the vehicle to continue to be driven by another normal motor through the complex transmission chain of the central clutch and coupler in the event of a single motor failure, significantly improving the redundancy and reliability of the system and preventing the entire vehicle from being paralyzed due to a single motor failure.

[0047] (3) The coupler structure of this invention is ingeniously designed. By locking the gear ring with a brake, the planetary transmission device can be reduced to a fixed-axis gear train, realizing a single-input mode. When the brake is released and the synchronizer is engaged, the sun gear and the gear ring are allowed to input at different speeds, realizing stepless coupling and power splitting of dual power sources. This mechanism enables the control system to precisely adjust the torque distribution between the front and rear axles according to the working conditions. For example, in the front or rear axle power distribution mode, by controlling the hydraulic pressure of the drive clutch to forcibly split part of the power to the other axle, a differentiated torque distribution between the front and rear axles is realized, adapting to the needs of complex road conditions. At the same time, this design eliminates the complex mechanical transmission mechanism of traditional parallel hybrid power, reduces the number of transmission components and power loss, and improves transmission efficiency.

[0048] (4) This invention further introduces an intelligent power and electrical control system. Using the TCU as the central nervous system, it monitors vehicle status and environmental information in real time, coordinating the timing of the engine, generator, dual motors, and various actuators. This not only achieves millisecond-level power response and smooth mode switching, but also optimizes charging and discharging strategies based on the SOC state, preventing overcharging and over-discharging of the battery and extending battery life. Combined with symmetrical mechanical layout optimization and the setting of wheel-side reducers, this solution ensures balanced front and rear axle loads and improves stability during field operations while further amplifying the driving torque, enhancing the passability and heavy-load operation capacity of the agricultural machinery, and achieving an overall organic unity of environmental protection, energy saving, high efficiency, and intelligence. Attached Figure Description

[0049] Figure 1 This is a simplified diagram of the power transmission system of the present invention;

[0050] Figure 2 A simplified diagram of the power transmission of the coupler;

[0051] Figure 3 This is a simplified diagram of the power transmission of the drive wheel assembly.

[0052] In the diagram: 1. Engine; 2. PTO module; 3. Generator; 4. Central clutch; 5. Motor; 6. Coupler; 6-1. Input gear shaft; 6-2. Planetary transmission; 6-3. Transmission gear shaft; 6-4. Brake; 6-5. Connecting shaft; 6-6. Transmission gear; 6-7. Synchronizer; 7. Drive clutch; 8. Drive wheel assembly; 8-1. Main reducer; 8-2. Differential; 8-3. Drive wheel; 8-4. Wheel-side reducer.

[0053] Figure 1 The solid black line in the middle represents mechanical transmission connections, the dashed red line represents electrical connections, and the double-dotted blue line represents signal connections. Detailed Implementation

[0054] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0055] In the description of this invention, it should be noted that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed when in use. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0056] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," "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 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. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0057] Example 1:

[0058] Combined with appendix Figures 1-2A multi-mode hybrid tractor drive system and its control method are disclosed, comprising an engine 1, an electric drive system, and a central clutch 4. The engine 1 is used to achieve power output in fuel mode; a PTO module 2 and a generator 3 are both connected to the engine 1 via transmission; the PTO module 2 is independent of the electric drive system, directly obtaining power from the engine 1, enabling high torque output and ensuring stable operation of the implements even when the electric system's power is insufficient or continuous high-power operation is required, such as rotary tillage or sowing, without being limited by battery capacity; the generator 3 is used to charge the power battery pack, converting the mechanical energy generated by the engine 1 into electrical energy stored in the power battery pack, extending the vehicle's range and optimizing the engine's operating range to reduce fuel consumption.

[0059] The electric drive system consists of two sets, namely electric drive system a and electric drive system b, both of which are powered by a power battery pack; a central clutch 4 is installed between the two sets of electric drive systems.

[0060] Both electric drive system a and electric drive system b include a motor 5, a coupler 6, a drive clutch 7, and a drive wheel assembly 8. The motor 5 is powered by a battery pack. The coupler 6 is driven by the motor 5; it is a key device for power transmission and distribution, possessing power convergence and divergence functions. The drive clutch 7 is driven by the coupler 6; the drive wheel assembly 8 is also driven by the drive clutch 7; the power output from the coupler 6 can be transmitted to the drive wheel assembly 8 via the drive clutch 7.

[0061] The drive wheel assembly 8 of electric drive system a is the front wheel assembly, and the drive wheel assembly 8 of electric drive system b is the rear wheel assembly; the central clutch 4 is connected to the coupler 6 of electric drive system a and electric drive system b to realize the power transmission and interruption between electric drive system a and electric drive system b, thereby establishing the connection or isolation state of the front and rear axle power.

[0062] Specifically, the coupler 6 includes an input gear shaft 6-1, a planetary transmission device 6-2, a transmission gear shaft 6-3, a brake 6-4, and a connecting shaft 6-5. One end of the input gear shaft 6-1 is connected to the output shaft of the motor 5. The planetary transmission device 6-2 includes a housing, a sun gear, planet gears, a planet carrier, and a gear ring, with the gear ring rotatably connected to the housing and having an external tooth structure. The axle of the sun gear is the input shaft of the entire planetary transmission device 6-2, and the axle of the sun gear is connected to the end of the input gear shaft 6-1 away from the motor 5 to achieve power input. The axle of the planet carrier of the planetary transmission device 6-2 is the output shaft, and the axle of the planet carrier is connected to the drive clutch 7 to transmit power to the drive clutch 7. When engaged, the drive clutch 7 transmits power to the corresponding drive wheel assembly 8 to achieve forward or reverse movement of the tractor.

[0063] The teeth of the transmission gear shaft 6-3 mesh with the ring gear of the planetary transmission device 6-2. The brake 6-4 is installed at one end of the transmission gear shaft 6-3. When the brake 6-4 is locked, the transmission gear shaft 6-3 is fixed, thus locking the ring gear. When the ring gear is locked, the planetary transmission device 6-2 degenerates into a fixed-axis gear train or a simple reduction mechanism. Power can only be transmitted through the input gear shaft 6-1 via the sun gear and planet gears to the planet carrier for output. At this time, the coupler 6 is in single-input mode. One end of the connecting shaft 6-5 is connected to the central clutch 4, and a synchronizer 6-7 is installed at the other end of the connecting shaft 6-5. A transmission gear 6-6 is rotatably connected to the shaft of the connecting shaft 6-5. The transmission gear 6-6 meshes with the input gear shaft 6-1, forming a constantly meshed path from the input gear shaft 6-1 to the transmission gear 6-6. The synchronizer 6-7 is used to achieve selective power transmission between the connecting shaft 6-5 and the transmission gear shaft 6-3 or the transmission gear 6-6.

[0064] When the brake 6-4 is released and the synchronizer 6-7 engages with the transmission gear shaft 6-3, the power from the connecting shaft 6-5 is transmitted to the transmission gear shaft 6-3 through the synchronizer 6-7. The transmission gear shaft 6-3 drives the gear ring to rotate. Due to the meshing relationship between the gear ring and the planetary gears, the rotation direction of the gear ring is opposite to that of the sun gear. At this time, the power from the input gear shaft 6-1 and the power from the connecting shaft 6-5 are vectored and synthesized within the planetary transmission device 6-2, and output together from the planet carrier shaft. This structure allows the input gear shaft 6-1 and the connecting shaft 6-5 to be input at different speeds without mechanical interference, realizing stepless coupling and power splitting of dual power sources, which facilitates the control system to accurately adjust the torque distribution between the front and rear shafts according to the working conditions.

[0065] Since this embodiment has two sets of electric drive systems, different working modes can be achieved by controlling the state combination of electric drive system a, electric drive system b and central clutch 4. The working modes include single drive mode and dual drive mode.

[0066] The single-drive mode is divided into front-drive mode and rear-drive mode. In the single-drive mode, the central clutch 4 is disengaged, and electric drive system a or electric drive system b works independently to drive the front wheel assembly to achieve front-drive mode or drive the rear wheel assembly to achieve rear-drive mode, which is suitable for light-load transportation or specific road surface adhesion conditions; or the central clutch 4 is engaged, and the power of electric drive system b is transmitted to electric drive system a to drive the front wheel assembly to achieve front-drive mode; or the power of electric drive system a is transmitted to electric drive system b to drive the rear wheel assembly to achieve rear-drive mode; or the central clutch 4 is engaged, and electric drive system a or electric drive system b works independently to drive both the front wheel assembly and the rear wheel assembly to achieve conventional four-wheel drive mode.

[0067] Specifically, in single-drive mode:

[0068] When the central clutch 4 is disengaged, the brake 6-4 of the electric drive system a is locked, the drive clutch 7 is engaged, and the motor 5 is working. The power transmission path of the motor 5 of the electric drive system a is sequentially the input gear shaft 6-1 of the electric drive system a, the planetary transmission device 6-2, the drive clutch 7, and the front wheel assembly. At this time, the electric drive system b is not working, and the tractor runs in front-wheel drive mode.

[0069] When the central clutch 4 is disengaged, the brake 6-4 of the electric drive system b is locked, the drive clutch 7 is engaged, and the motor 5 is working. The power transmission path of the motor 5 of the electric drive system b is sequentially the input gear shaft 6-1 of the electric drive system b, the planetary transmission device 6-2, the drive clutch 7, and the rear wheel assembly. At this time, the electric drive system a is not working, and the tractor runs in rear-wheel drive mode.

[0070] When the central clutch 4 is engaged, the brake 6-4 of electric drive system a is released, the drive clutch 7 is disengaged, the motor 5 operates, and the synchronizer 6-7 engages with the transmission gear 6-6; when the brake 6-4 of electric drive system b is locked, the drive clutch 7 is engaged, the motor 5 is in a de-energized coasting state, and the synchronizer 6-7 engages with the transmission gear 6-6; the power transmission path of the motor 5 of electric drive system a is sequentially the input gear shaft 6-1 of electric drive system a, the transmission gear 6-6, the synchronizer 6-7, the connecting shaft 6-5, and the central clutch 4, and then transmitted via the central clutch 4 to the connecting shaft 6-5, the synchronizer 6-7, the transmission gear 6-6, the input gear shaft 6-1, the planetary transmission device 6-2, the drive clutch 7, and the rear wheel assembly of electric drive system b; in this state, the front axle motor 5 acts as a power source, driving the rear wheels through the reverse transmission path of the coupler 6 of electric drive system b, realizing cross-axle drive with front-wheel drive as the main mode.

[0071] When the central clutch 4 is engaged, the brake 6-4 of electric drive system a is locked, the drive clutch 7 is engaged, the motor 5 is in a de-energized coasting state, and the synchronizer 6-7 is engaged with the transmission gear 6-6. When the brake 6-4 of electric drive system b is released, the drive clutch 7 is disengaged, the motor 5 operates, and the synchronizer 6-7 is engaged with the transmission gear 6-6. The power transmission path of the motor 5 of electric drive system b is sequentially: input gear shaft 6-1 of electric drive system b, transmission gear 6-6, synchronizer 6-7, connecting shaft 6-5, central clutch 4, and then transmitted via the central clutch 4 to the connecting shaft 6-5, synchronizer 6-7, transmission gear 6-6, input gear shaft 6-1, planetary transmission device 6-2, drive clutch 7, and front wheel assembly of electric drive system a. In this state, the rear axle motor 5 acts as a power source, driving the front wheels through the reverse transmission path of the coupler 6 of electric drive system a, realizing a rear-wheel drive-dominated cross-axle drive.

[0072] When the central clutch 4 is engaged, the brake 6-4 of electric drive system a is locked, the drive clutch 7 is engaged, the motor 5 operates, and the synchronizer 6-7 engages with the transmission gear 6-6; when the brake 6-4 of electric drive system b is locked, the drive clutch 7 is engaged, the motor 5 is in a de-energized coasting state, and the synchronizer 6-7 engages with the transmission gear 6-6; the power of the motor 5 of electric drive system a is divided into two paths. One path is transmitted sequentially through the input gear shaft 6-1 of electric drive system a, the planetary transmission device 6-2, the drive clutch 7, and the front wheel assembly; the other path is transmitted sequentially through the input gear shaft 6-1 of electric drive system a, the transmission gear 6-6, the synchronizer 6-7, the connecting shaft 6-5, and the central clutch 4; and through the connecting shaft 6-5, the synchronizer 6-7, the transmission gear 6-6, the input gear shaft 6-1, the planetary transmission device 6-2, the drive clutch 7, and the rear wheel assembly of electric drive system b. This state realizes a four-wheel drive mode with the front axle motor as the main power source, driving both the front and rear wheels, and the power of the rear axle comes entirely from the power split of the front axle.

[0073] When the central clutch 4 is engaged, the brake 6-4 of electric drive system a is locked, the drive clutch 7 is engaged, the motor 5 is in a de-energized coasting state, and the synchronizer 6-7 is engaged with the transmission gear 6-6; when the brake 6-4 of electric drive system b is locked, the drive clutch 7 is engaged, the motor 5 operates, and the synchronizer 6-7 is engaged with the transmission gear 6-6; the power of the motor 5 of electric drive system b is divided into two paths. One path is transmitted sequentially through the input gear shaft 6-1 of electric drive system b, the planetary transmission device 6-2, the drive clutch 7, and the rear wheel assembly; the other path is transmitted sequentially through the input gear shaft 6-1 of electric drive system b, the transmission gear 6-6, the synchronizer 6-7, the connecting shaft 6-5, the central clutch 4, the connecting shaft 6-5 of electric drive system a, the synchronizer 6-7, the transmission gear 6-6, the input gear shaft 6-1, the planetary transmission device 6-2, the drive clutch 7, and the front wheel assembly; this state realizes a four-wheel drive mode with the rear axle motor as the main power source, driving both the front and rear wheels, and the power of the front axle comes entirely from the power split of the rear axle.

[0074] When the actual usage environment changes or one of the motors 5 in electric drive system a or electric drive system b fails, the system can flexibly switch to any of the above working modes and continue to provide driving force to the whole vehicle through the complex transmission chain of the central clutch 4 and coupler 6 using the normally working motor, which significantly improves the redundancy and reliability of the system and avoids the paralysis of the whole vehicle due to the failure of a single unit.

[0075] In dual-drive mode, the motors 5 of electric drive system a and electric drive system b work simultaneously, and the central clutch 4 engages. The four-drive mode includes a variety of enhanced drive strategies:

[0076] In Super Front-Wheel Drive mode, electric drive system a and electric drive system b work together to drive the front wheel assembly, aiming to achieve maximum front axle traction to cope with extreme mud or climbing conditions.

[0077] Specifically, in super front-wheel drive mode, the brake 6-4 of electric drive system a is released, the drive clutch 7 is engaged, and the synchronizer 6-7 is engaged with the transmission gear shaft 6-3; the drive clutch 7 of electric drive system b is disengaged, and the synchronizer 6-7 is engaged with the transmission gear 6-6; the power transmission path of motor 5 of electric drive system a is sequentially the input gear shaft 6-1 of electric drive system a, planetary transmission device 6-2, drive clutch 7, and front wheel assembly; the power transmission path of motor 5 of electric drive system b is sequentially the input gear shaft 6-1 of electric drive system b, transmission gear 6-6, synchronizer 6-7, and connecting shaft 6-5. The central clutch 4 transmits power to the connecting shaft 6-5, synchronizer 6-7, and transmission gear shaft 6-3 of electric drive system a, thereby driving the ring gear of the planetary transmission device 6-2 of electric drive system a. At this time, the sun gear of electric drive system a receives power from its own motor 5, and the ring gear receives power from the motor 5 of electric drive system b transmitted through the central clutch 4. The rotation direction of the ring gear is opposite to that of the sun gear. The two power sources are coupled and superimposed within the planetary transmission device 6-2, and are output together from the planet carrier shaft, realizing the combined force of the motors 5 of electric drive system a and electric drive system b to drive the front wheel assembly, greatly improving the front axle torque output.

[0078] In Super Rear-Wheel Drive mode, electric drive system a and electric drive system b work together to drive the rear wheel assembly, aiming to achieve maximum rear axle traction.

[0079] Specifically, in super rear-wheel drive mode, the brake 6-4 of electric drive system b is released, the drive clutch 7 is engaged, and the synchronizer 6-7 is engaged with the transmission gear shaft 6-3; the drive clutch 7 of electric drive system a is disengaged, and the synchronizer 6-7 is engaged with the transmission gear 6-6; the power transmission path of the motor 5 of electric drive system b is sequentially the input gear shaft 6-1 of electric drive system b, the planetary transmission device 6-2, the drive clutch 7, and the rear wheel assembly; the power transmission path of the motor 5 of electric drive system a is sequentially the input gear shaft 6-1 of electric drive system a, the transmission gear 6-6, the synchronizer 6-7, and the connecting gear 6-3. The power is transmitted from the connecting shaft 6-5 and the central clutch 4 to the connecting shaft 6-5, synchronizer 6-7, and transmission gear shaft 6-3 of the electric drive system b, thereby driving the ring gear of the planetary transmission device 6-2 of the electric drive system b. At this time, the sun gear of the electric drive system b receives power from its own motor 5, and the ring gear receives power from the motor 5 of the electric drive system a transmitted through the central clutch 4. The rotation direction of the ring gear is opposite to that of the sun gear. The two power sources are coupled and superimposed in the planetary transmission device 6-2, and are output together from the planet carrier gear shaft, so as to realize the combined force of the motors 5 of the electric drive system a and the electric drive system b to drive the rear wheel assembly.

[0080] In the front axle power distribution mode, electric drive system a drives the front wheel assembly, while electric drive system a and electric drive system b jointly drive the rear wheel assembly, achieving differentiated torque distribution between the front and rear axles to adapt to complex road conditions.

[0081] Specifically, in the front axle power distribution mode, the brake 6-4 of electric drive system a is locked, the drive clutch 7 is engaged, and the synchronizer 6-7 is engaged with the transmission gear 6-6; the brake 6-4 of electric drive system b is released, the drive clutch 7 is engaged, and the synchronizer 6-7 is engaged with the transmission gear shaft 6-3. The power transmission path of the motor 5 of electric drive system b is sequentially the input gear shaft 6-1 of electric drive system b, the planetary transmission device 6-2, the drive clutch 7, and the rear wheel assembly, providing basic rear drive force. The power of motor 5 in electric drive system a is divided into two paths. One path transmits power sequentially through the input gear shaft 6-1, planetary transmission device 6-2, drive clutch 7, and front wheel assembly of electric drive system a, driving the front wheels. The other path transmits power sequentially through the input gear shaft 6-1, transmission gear 6-6, synchronizer 6-7, connecting shaft 6-5, and central clutch 4 of electric drive system a, transmitting power to the connecting shaft 6-5, synchronizer 6-7, and transmission gear shaft 6-3 of electric drive system b, driving the ring gear of planetary transmission device 6-2. In electric drive system b, the ring gear rotates in the opposite direction to the sun gear, achieving power coupling between the input gear shaft 6-1 and the cross-axis power from electric drive system a, both outputting from the planet carrier shaft. By controlling the hydraulic pressure of the drive clutch 7 of electric drive system a, the power ratio to the front wheel assembly is controlled, and the remaining power is forcibly diverted to the rear axle, thus enabling part of the power from electric drive system a and motor 5 of electric drive system b to jointly drive the rear wheel assembly, flexibly adjusting the torque ratio between the front and rear axles.

[0082] In the rear axle power distribution mode, electric drive system b drives the rear wheel assembly, while electric drive system a and electric drive system b jointly drive the front wheel assembly.

[0083] Specifically, in the rear axle power distribution mode, the brake 6-4 of electric drive system b is locked, the drive clutch 7 is engaged, and the synchronizer 6-7 is engaged with the transmission gear 6-6; the brake 6-4 of electric drive system a is released, the drive clutch 7 is engaged, and the synchronizer 6-7 is engaged with the transmission gear shaft 6-3. The power transmission path of the motor 5 of electric drive system a is sequentially the input gear shaft 6-1 of electric drive system a, the planetary transmission device 6-2, the drive clutch 7, and the front wheel assembly, providing basic front driving force. The power of motor 5 in electric drive system b is divided into two paths. One path transmits power sequentially through the input gear shaft 6-1, planetary transmission device 6-2, drive clutch 7, and rear wheel assembly of electric drive system b, driving the rear wheels. The other path transmits power sequentially through the input gear shaft 6-1, transmission gear 6-6, synchronizer 6-7, connecting shaft 6-5, and central clutch 4 of electric drive system b, transmitting power to the connecting shaft 6-5, synchronizer 6-7, and transmission gear shaft 6-3 of electric drive system a, driving the ring gear of planetary transmission device 6-2. In electric drive system a, the ring gear rotates in the opposite direction to the sun gear, achieving power coupling between the input gear shaft 6-1 and the cross-axis power from electric drive system b, both outputting from the planet carrier shaft. By controlling the hydraulic pressure of drive clutch 7 of electric drive system b, the power ratio to the rear wheel assembly is controlled, and the remaining power is forcibly diverted to the front axle, thus enabling part of the power from electric drive system b and motor 5 of electric drive system a to jointly drive the front wheel assembly, further optimizing traction performance.

[0084] Example 2:

[0085] Combined with appendix Figure 1 A multi-mode hybrid tractor drive system and its control method are disclosed. The difference between the system and Embodiment 1 is that, based on Embodiment 1, the system also includes a power control system and an electric control system to achieve intelligent energy management and motion control of the entire vehicle.

[0086] The power control system includes an inverter electrically connected to the generator 3, which rectifies the AC power generated by the generator 3 into DC power; and a battery management system, a power battery pack, and an integrated drive motor controller, which are electrically and signal-connected to the inverter in sequence. The battery management system monitors the voltage, current, temperature, and SOC status of the power battery pack in real time, and works in conjunction with the inverter to optimize the charging and discharging strategy, prevent overcharging and over-discharging, and extend battery life. The integrated drive motor controller is electrically and signal-connected to the motors 5 of the two electric drive systems, receives commands from the upper layer, and precisely controls the torque, speed, and direction of rotation of the motors 5 to achieve millisecond-level power response.

[0087] The power control system includes a TCU, which acts as the nerve center of the vehicle. It is connected to the generator 3, inverter, battery management system, integrated drive motor controller, and the motors 5 of the two electric drive systems, the brakes 6-4 and synchronizers 6-7 of the coupler 6, and the drive clutch 7. The TCU calculates the optimal power distribution scheme in real time through a preset control algorithm based on the driver's operating intentions (such as throttle opening and gear selection), vehicle driving status (such as vehicle speed, wheel speed, and acceleration), and environmental information (such as road adhesion coefficient). It then issues commands to coordinate the start-stop and output power of the engine 1, the power generation load of the generator 3, the torque output of each motor 5, and the action sequence of each actuator (brake 6-4, synchronizer 6-7, drive clutch 7, and central clutch 4) to ensure smooth and shock-free power switching in various operating modes and maximize the energy-saving and power advantages of the hybrid system.

[0088] Example 3:

[0089] Combined with appendix Figure 1 and 3 A multi-mode hybrid tractor drive system and its control method are disclosed. Based on Embodiment 1 or 2, the mechanical layout is optimized. The two sets of electric drive systems are arranged along the length of the tractor, and electric drive system a and electric drive system b are symmetrically arranged about the central clutch 4. This symmetrical layout not only makes the front and rear axle load distribution of the whole vehicle more balanced, improving the stability and maneuverability of the tractor when working in the field, but also simplifies the arrangement of the drive shaft, reduces energy loss and mechanical vibration in the power transmission process, and facilitates modular production and maintenance, thereby reducing manufacturing costs.

[0090] Furthermore, the drive wheel assembly 8 includes a main reducer 8-1, a differential 8-2, and drive wheels 8-3. The main reducer 8-1 is connected to the drive clutch 7 to reduce the rotational speed and increase the torque; the differential 8-2 is connected to the main reducer 8-1 to allow the left and right wheels to rotate at different speeds when the tractor turns, preventing tire wear and steering difficulties; there are two drive wheels 8-3, which are respectively connected to the two output shafts of the differential 8-2 to form a complete wheel-end drive unit with a compact structure and high transmission efficiency.

[0091] Furthermore, a wheel-side reducer 8-4 is installed between the drive wheel 8-3 and the differential 8-2. The wheel-side reducer 8-4 enables secondary speed reduction and torque amplification from the differential 8-2 to the drive wheel 8-3. The wheel-side reducer 8-4 further amplifies the driving torque, making it particularly suitable for low-speed, high-torque conditions such as heavy-load tillage and traction of tractors. At the same time, it reduces the size and stress on the main reducer and differential, improves the reliability of the transmission system and ground clearance, and enhances the passability of agricultural machinery.

[0092] The parts of this invention not described in detail are prior art. It will be apparent to those skilled in the art that this invention is not limited to the details of the above exemplary embodiments, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be regarded as exemplary and non-limiting in all respects, and are intended to encompass all changes falling within the meaning and scope of equivalents within this invention.

Claims

1. A multi-mode hybrid tractor drive system, characterized in that, include: Engine (1); PTO module (2) is connected to the engine (1) via transmission; The generator (3) is connected to the engine (1) for charging the power battery pack; The electric drive system consists of two sets, namely electric drive system a and electric drive system b, both of which are powered by a battery pack. The central clutch (4) is installed between the two sets of electric drive systems; The electric drive system includes: Motor (5); Coupler (6) is connected to the motor (5) for transmission; Drive the clutch (7) and connect it to the coupler (6) for transmission; The drive wheel assembly (8) is connected to the drive clutch (7) for transmission; the drive wheel assembly (8) of the electric drive system a is the front wheel assembly, and the drive wheel assembly (8) of the electric drive system b is the rear wheel assembly; The central clutch (4) is connected to the coupler (6) of electric drive system a and electric drive system b to realize the power transmission between electric drive system a and electric drive system b; The coupler (6) includes: The input gear shaft (6-1) is connected at one end to the output shaft of the motor (5) for transmission. The planetary transmission device (6-2) is connected to the other end of the input gear shaft (6-1); the output end of the planetary transmission device (6-2) is connected to the drive clutch (7); and the gear ring of the planetary transmission device (6-2) is rotatably connected to its housing. The transmission gear shaft (6-3) has its teeth meshing with the gear ring of the planetary transmission device (6-2); The brake (6-4) is installed at one end of the transmission gear shaft (6-3); The connecting shaft (6-5) is connected at one end to the central clutch (4) for transmission. The transmission gear (6-6) is rotatably connected to the connecting shaft (6-5) on the same axis; the transmission gear (6-6) meshes with the input gear shaft (6-1); Synchronizer (6-7), installed at the other end of connecting shaft (6-5), is used to realize power transmission between connecting shaft (6-5) and transmission gear shaft (6-3) or transmission gear (6-6).

2. The control method for the multi-mode hybrid tractor drive system as described in claim 1, characterized in that, Different working modes are achieved by controlling electric drive system a, electric drive system b and central clutch (4), including single drive mode and dual drive mode; Among them, the single drive mode is divided into front drive mode and rear drive mode. In the single drive mode, the central clutch (4) is disengaged, and the electric drive system a or the electric drive system b works independently to drive the front wheel assembly to achieve the front drive mode or drive the rear wheel assembly to achieve the rear drive mode; or the central clutch (4) is engaged, and the power of the electric drive system b is transmitted to the electric drive system a to drive the front wheel assembly to achieve the front drive mode; or the power of the electric drive system a is transmitted to the electric drive system b to drive the rear wheel assembly to achieve the rear drive mode; or the electric drive system a or the electric drive system b works independently to drive the front wheel assembly and the rear wheel assembly to achieve the four-wheel drive mode. In dual-drive mode, electric drive system a and electric drive system b work simultaneously, and the central clutch (4) engages. The four-drive mode includes: In Super Front-Wheel Drive mode, electric drive system a and electric drive system b jointly drive the front wheel assembly; In Super Rear-Wheel Drive mode, electric drive system a and electric drive system b jointly drive the rear wheel assembly; In the front axle power distribution mode, electric drive system a drives the front wheel assembly, and electric drive system a and electric drive system b jointly drive the rear wheel assembly; by controlling the oil pressure of the drive clutch (7) of electric drive system a, its power output is controlled, and the proportion of power from electric drive system a to the front wheel assembly is controlled. In the rear axle power distribution mode, electric drive system b drives the rear wheel assembly, and electric drive system a and electric drive system b jointly drive the front wheel assembly; by controlling the oil pressure of the drive clutch (7) of electric drive system b, its power output is controlled, thereby realizing the proportion of power from electric drive system b to the rear wheel assembly.

3. The control method for the multi-mode hybrid tractor drive system as described in claim 2, characterized in that, It also includes the power control system and the electric control system; The power control system includes an inverter electrically connected to the generator (3), and a battery management system, a power battery pack, and an integrated drive motor controller that are electrically and signal-connected to the inverter in sequence; the integrated drive motor controller is electrically and signal-connected to the motors (5) of the two electric drive systems respectively. The power control system includes a TCU, which is signal connected to the generator (3), inverter, battery management system, integrated drive motor controller, and the motors (5), couplers (6), brakes (6-4), synchronizers (6-7), and drive clutches (7) of the two electric drive systems.

4. The multi-mode hybrid tractor drive system as described in claim 1, characterized in that, The drive wheel assembly (8) includes: The main reducer (8-1) is connected to the drive clutch (7) in a transmission manner; The differential (8-2) is connected to the main reducer (8-1) in a transmission manner; There are two drive wheels (8-3), which are respectively connected to the two output shafts of the differential (8-2).

5. The multi-mode hybrid tractor drive system as described in claim 4, characterized in that, A wheel-side reducer (8-4) is installed between the drive wheel (8-3) and the differential (8-2), through which power is transmitted from the differential (8-2) to the drive wheel (8-3).

6. The multi-mode hybrid tractor drive system as described in claim 1, characterized in that, The two sets of electric drive systems are arranged along the length of the tractor, and electric drive system a and electric drive system b are symmetrically arranged about the central clutch (4).

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