Hybrid power tractor driving system and driving mode switching method

Abstract

The invention relates to the technical field of agricultural new energy machinery, in particular to a hybrid power tractor driving system and a driving mode switching method, and the hybrid power tractor driving system comprises a dynamic coupling driving system, a control system and a power battery; the power coupling driving system comprises a first motor, a second motor, an engine, a first motor controller, a second motor controller, an engine controller and a power gearbox. The first motor, the second motor and the engine are installed at the power input shaft end of the power gearbox. The control system comprises a first motor controller, a second motor controller, an engine controller and a vehicle control unit, and the vehicle control unit communicates with the first motor controller, the second motor controller, the engine controller and the power battery through a CAN bus. Through cooperative control of the rear-drive double motors and the engine, multiple working modes are achieved, and the energy utilization efficiency and the working condition adaptability are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural new energy machinery, and particularly relates to a hybrid tractor drive system and a drive mode switching method. Background Art

[0002] With the continuous improvement of environmental protection requirements and the modernization of agricultural machinery, traditional tractors powered by internal combustion engines face problems such as low energy efficiency and high emissions, and there is an urgent need to introduce a new power system to improve work efficiency and reduce pollution.

[0003] Traditional agricultural machinery or engineering vehicles mostly use a single diesel engine for driving, and cannot flexibly switch the power input according to the working conditions, resulting in problems such as high fuel consumption, high emissions, and energy waste. When operating the power take-off (PTO), the driving power often needs to be sacrificed, affecting the operation efficiency, and energy recovery cannot be achieved. Most existing hybrid drive systems use a single-motor structure, with a single drive mode and insufficient energy conversion. Especially in the case of high-power requirements and complex working environments, traditional systems are difficult to meet the needs of high efficiency and long-term high-load work, difficult to balance the vehicle driving and PTO operation requirements, lack an efficient torque coupling mechanism, and have poor power output stability. The pure electric solution is limited by the battery capacity and charging facilities, with insufficient endurance and unable to meet the long-term operation requirements, lacking an efficient in-vehicle charging mechanism.

[0004] Some solutions attempt to use parallel drive of the motor and the engine, and an integrated design of PTO and drive, but do not solve the problem of transmission efficiency when multiple power sources are coupled, and do not achieve the dynamic switching function of motor power generation and drive. Developing a tractor drive system with multi-mode, hybrid power, and adjustable drive methods has become the key to improving the efficiency of agricultural machinery. In the prior art, how to effectively combine electric drive and engine drive to improve the flexibility of power output and the energy efficiency of the system is still a technical problem to be solved.

[0005] Under this background, introducing a hybrid drive system has become an inevitable trend in the power upgrade of agricultural tractors. The hybrid system breaks the limitations of traditional single power sources through the coordinated integration of the motor and the engine at the structural and control levels, and has many significant advantages. The system can adopt a pure electric drive mode during light load or low-speed operation, significantly reducing fuel consumption and noise pollution; during heavy load or long-term operation, through parallel or coupled drive of the engine and the motor, the power output efficiency and operation continuity are improved. The hybrid system supports an energy recovery mechanism, and converts kinetic energy into electrical energy for storage through the reverse operation of the motor during vehicle braking or deceleration, realizing the reuse of energy. The system has multi-mode drive capabilities and intelligent control strategies, and can automatically switch to the optimal working mode according to the working conditions, taking into account both driving performance and operation efficiency.

[0006] Compared with traditional systems, hybrid drive systems not only improve energy utilization efficiency and environmental adaptability, but also demonstrate obvious technical advantages in the diversity, complexity, and continuity of agricultural operations. Developing a multi-mode hybrid drive system applicable to agricultural operation scenarios and capable of dynamic regulation has important practical significance and technical value for promoting the green and efficient development of agricultural machinery. Summary of the Invention

[0007] The object of the present invention is to provide a hybrid tractor drive system and a drive mode switching method, which solve the problems of insufficient endurance, inability to meet the requirements of long-term operation, and lack of an efficient on-vehicle charging mechanism existing in the prior art.

[0008] To achieve the above object, the present invention provides a hybrid tractor drive system and a drive mode switching method, including:

[0009] A power coupling drive system, a control system, and a power battery;

[0010] The power coupling drive system includes a first motor, a second motor, an engine, a first motor controller, a second motor controller, an engine controller, and a power transmission gearbox. The first motor, the second motor, and the engine are respectively installed at the power input shaft end of the power transmission gearbox. The first motor and the second motor are respectively electrically connected to the power battery through the first motor controller and the second motor controller. The power coupling drive system is used to drive the vehicle and PTO output.

[0011] The control system includes a first motor controller, a second motor controller, an engine controller, and a vehicle controller. The vehicle controller communicates with the first motor controller, the second motor controller, the engine controller, and the power battery through the CAN bus, and is used to coordinate and control the operating states of the motor and the engine.

[0012] The first motor and the second motor are AC motors, and the first motor controller and the second motor controller are both AC motor controllers; wherein, the first motor and the engine are mainly used for driving functions, and the second motor has both driving functions and power generation functions.

[0013] When the second motor is in the driving working state, the first motor and the second motor are powered by the power battery; when the second motor is in the power generation state, the engine drives the second motor to generate electricity, and the generated electric energy is used to supply power to the first motor.

[0014] The power transmission gearbox includes: a first gear set, a shift gear set, a PTO shift gear set, a right half shaft of electromagnetic clutch 1, a second gear set, electromagnetic clutch 1, a third gear set, a left half shaft of electromagnetic clutch 1, a fourth gear set, a left half shaft of electromagnetic clutch 2, a fifth gear set, electromagnetic clutch 2, a left half shaft of electromagnetic clutch 3, a sixth gear set, a right half shaft of electromagnetic clutch 2, electromagnetic clutch 3, a seventh gear set, a right half shaft of electromagnetic clutch 3, an eighth gear set, and a ninth gear set.

[0015] Among them, the output shaft of the first motor is connected to the driving gear of the eighth gear set, and the driving gear of the ninth gear set meshes with the driven gear of the eighth gear set; the driving gears of the shift gear set and the seventh gear set mesh with the driven gear of the ninth gear set, and the driven gear of the seventh gear set is connected to the right half shaft of electromagnetic clutch 3; the driving gear of the first gear set meshes with the driven gear of the shift gear set, and the shaft where its driven gear is located is the rear-wheel power output shaft; the output shaft of the second motor is connected to the driving gear of the third gear set, and its driven gear is connected to the left half shaft of electromagnetic clutch 1; the output shaft of the engine is connected to the driving gear of the fourth gear set, and its driven gear meshes with the driving gears of the second gear set and the fifth gear set and the left half shaft of electromagnetic clutch 2 respectively; the driven gear of the second gear set is connected to the right half shaft of electromagnetic clutch 1, and the driven gear of the fifth gear set is connected to the left half shaft of electromagnetic clutch 3; the driving gear of the sixth gear set is connected to the right half shaft of electromagnetic clutch 2, and its driven gear meshes with the driving gear of the PTO shift gear set, and the shaft where the driven gear of the PTO shift gear set is located is the PTO power output shaft.

[0016] The power transmission gearbox supports six driving modes, including:

[0017] Mode 1: The first motor works, the shift gear set meshes, the PTO shift gear set disengages, electromagnetic clutch 1 disengages, electromagnetic clutch 2 disengages, electromagnetic clutch 3 disengages, and the power of the first motor is transmitted to the rear wheels through the eighth gear set, the ninth gear set, the shift gear set, and the first gear set. At this time, no power is transmitted to the PTO.

[0018] Mode 2: The engine works, the shift gear set meshes, the PTO shift gear set disengages, electromagnetic clutch 1 disengages, electromagnetic clutch 2 disengages, electromagnetic clutch 3 engages, and the engine power is transmitted to the rear wheels through the fourth gear set, the fifth gear set, the seventh gear set, the shift gear set, and the first gear set. At this time, no power is transmitted to the PTO.

[0019] Mode 3: The first motor and the second motor work, the shift gear set meshes, the PTO shift gear set disengages, electromagnetic clutch 1 engages, electromagnetic clutch 2 disengages, electromagnetic clutch 3 engages. The power of the first motor is torque-coupled with the power of the second motor after passing through the eighth gear set, the ninth gear set and the third gear set, the second gear set, the fifth gear set, the seventh gear set respectively. The coupled power is transmitted to the rear wheels through the shift gear set and the first gear set. At this time, no power is transmitted to the PTO.

[0020] Mode Four: The first motor and the engine are working, the shift gear set is engaged, the PTO shift gear set is disengaged, electromagnetic clutch one is disengaged, electromagnetic clutch two is disengaged, electromagnetic clutch three is engaged. The power of the first motor is torque-coupled with the power of the engine after passing through gear set eight and gear set nine and the power of the engine after passing through gear set four, gear set five, and gear set seven. The coupled power is transmitted to the rear wheels through the shift gear set and gear set one. At this time, no power is transmitted to the PTO.

[0021] Mode Five: The first motor, the second motor, and the engine are working, the shift gear set is engaged, the PTO shift gear set is disengaged, electromagnetic clutch one is engaged, electromagnetic clutch two is disengaged, electromagnetic clutch three is disengaged. The power of the engine drives the second motor to generate electricity through gear set four, gear set two, and gear set three. The power of the first motor is transmitted to the rear wheels through gear set eight, gear set nine, the shift gear set, and gear set one. At this time, no power is transmitted to the PTO.

[0022] Mode Six: The first motor and the engine are working, the shift gear set is engaged, the PTO shift gear set is engaged, electromagnetic clutch one is disengaged, electromagnetic clutch two is engaged, electromagnetic clutch three is disengaged. The power of the first motor is transmitted to the rear wheels through gear set eight, gear set nine, the shift gear set, and gear set one. The power of the engine is transmitted to the PTO through gear set six and the PTO shift gear set.

[0023] By controlling the engagement and disengagement of electromagnetic clutch one to control whether the power of the second motor is input, by controlling the engagement and disengagement of electromagnetic clutch two to control whether the power of the engine is input, by controlling the engagement and disengagement of electromagnetic clutch three to control whether the power of the first motor is input, by controlling the engagement and disengagement of the shift gear set to control whether the driving force of the rear wheels is output, and by controlling the engagement and disengagement of the PTO shift gear set to control whether the power of the PTO is output.

[0024] The beneficial effects of the present invention are as follows:

[0025] 1. The present invention supports multiple working modes (including pure electric drive, engine drive, dual-motor coupling drive, on-road charging, and PTO operation, etc.), adapts to complex working conditions, can be flexibly switched according to the working conditions, takes into account driving power and operation efficiency, thereby improving the adaptability of the tractor.

[0026] 2. Through the coordinated operation of the power battery, the electric motor, and the engine, the present invention can effectively improve the energy utilization rate, reduce fuel consumption and emissions, meet the requirements of modern agriculture for efficient and environmentally friendly machinery, and the system can efficiently utilize electric energy and mechanical energy during the mutual switching between the power generation and driving functions.

[0027] 3. The present invention adopts an electromagnetic clutch and a multi-gearbox design, which simplifies the mechanical structure while improving the power transmission efficiency, realizes the dynamic coupling and decoupling of the power source, and enhances the system reliability.

[0028] 4. The control system of the present invention coordinates the communication between the CAN bus and multiple motor controllers and engine controllers, simplifies the management and operation of the entire power system, improves the stability and reliability of the system, and can realize the switching between different driving modes through simple operations.

[0029] 5. The drive system of the present invention can provide optimal power output under different operating modes. Especially in the complex operating environment of a tractor, such as high load and long-time operation, it can provide stable power support to ensure the efficient operation of the tractor, and has both environmental protection and economy.

[0030] The technical solution of the present invention will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0031] Figure 1 is a schematic structural diagram of a hybrid tractor drive system according to a specific example of the present invention;

[0032] Figure 2 is a schematic structural diagram of a power coupling gearbox according to a specific example of the present invention;

[0033] Figure 3 is a flow chart of a mode switching strategy according to a specific example of the present invention;

[0034] Reference Signs:

[0035] 1, PTO output; 2, power gearbox; 3, second motor; 4, second motor controller; 5, vehicle controller; 6, power battery; 7, engine controller; 8, engine; 9, first motor controller; 10, first motor; 201, gear set one; 202, shift gear set; 203, PTO shift gear set; 204, electromagnetic clutch one right half shaft; 205, gear set two; 206, electromagnetic clutch one; 207, gear set three; 208, electromagnetic clutch one left half shaft; 209, gear set four; 210, electromagnetic clutch two left half shaft; 211, gear set five; 212, electromagnetic clutch two; 213, electromagnetic clutch three left half shaft; 214, gear set six; 215, electromagnetic clutch two right half shaft; 216, electromagnetic clutch three; 217, gear set seven; 218, electromagnetic clutch three right half shaft; 219, gear set eight; 220, gear set nine. Detailed Embodiments

[0036] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present invention is habitually placed during use. It is 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 should not be construed as a limitation to the present invention. In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "installed", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] The following will describe in detail the embodiments of the present invention with reference to the drawings. The described embodiments are some, but not all, of the embodiments of the present invention.

[0038] As Figure 1 shown, the present invention provides a configuration scheme for a hybrid tractor drive system, including a power coupling drive system, a control system, and a power battery; solid lines represent mechanical connections, and dashed lines represent electrical connections.

[0039] The power coupling drive system includes a first motor 10, a second motor 3, an engine 8, a first motor controller 9, a second motor controller 4, an engine controller 7, and a power transmission gearbox 2. The output ends of the first motor 10, the second motor 3, and the engine 8 are mechanically connected to the power transmission gearbox 2. After the power is input, it is output by the drive shaft through the power transmission gearbox 2 to drive the vehicle to travel, or it can be output by the PTO through the control of the PTO shift gear set to drive agricultural implements.

[0040] The control system includes a first motor controller 9, a second motor controller 4, an engine controller 7, and a vehicle controller 5. The vehicle controller 5 is electrically connected to the first motor controller 9, the second motor controller 4, and the engine controller 7. The vehicle controller 5 communicates with the first motor controller 9, the second motor controller 4, the engine controller 7, and the power battery 6 through the CAN bus, and is used to coordinately control the operating states of the motors and the engine to achieve the control of the whole vehicle.

[0041] The first motor 10 and the second motor 3 are AC motors, and the first motor controller 9 and the second motor controller 4 are both AC motor controllers; among them, the first motor 10 and the engine 8 are mainly used for driving functions, and the second motor 3 has both driving functions and power generation functions.

[0042] When the second motor 3 is in the driving state, the first motor 10 and the second motor 3 are powered by the power battery 6; when the second motor 3 is in the power generation state, the second motor 3 is driven by the engine 8 to generate electricity, and the generated electric energy is used to supply power to the first motor 10.

[0043] The power transmission gearbox 2 is as Figure 2 shown. The power transmission gearbox 2 includes: a first gear set 201, a shift gear set 202, a PTO shift gear set 203, a right half shaft of the first electromagnetic clutch 204, a second gear set 205, a first electromagnetic clutch 206, a third gear set 207, a left half shaft of the first electromagnetic clutch 208, a fourth gear set 209, a left half shaft of the second electromagnetic clutch 210, a fifth gear set 211, a second electromagnetic clutch 212, a left half shaft of the third electromagnetic clutch 213, a sixth gear set 214, a right half shaft of the second electromagnetic clutch 215, a third electromagnetic clutch 216, a seventh gear set 217, a right half shaft of the third electromagnetic clutch 218, an eighth gear set 219, and a ninth gear set 220.

[0044] Among them, the output shaft of the first motor 10 is connected to the driving gear of the eighth gear set 219, and the driving gear of the ninth gear set 220 meshes with the driven gear of the eighth gear set 219; the driving gears of the shift gear set 202 and the seventh gear set 217 mesh with the driven gear of the ninth gear set 220, and the driven gear of the seventh gear set 217 is connected to the right half shaft 218 of the third electromagnetic clutch; the driving gear of the first gear set 201 meshes with the driven gear of the shift gear set 202, and the shaft where its driven gear is located is the rear-wheel power output shaft; the output shaft of the second motor 3 is connected to the driving gear of the third gear set 207, and its driven gear is connected to the left half shaft 208 of the first electromagnetic clutch; the output shaft of the engine 8 is connected to the driving gear of the fourth gear set 209, and its driven gear meshes with the driving gears of the second gear set 205, the fifth gear set 211 and the left half shaft 210 of the second electromagnetic clutch respectively; the driven gear of the second gear set 205 is connected to the right half shaft 204 of the first electromagnetic clutch, and the driven gear of the fifth gear set 211 is connected to the left half shaft 213 of the third electromagnetic clutch; the driving gear of the sixth gear set 214 is connected to the right half shaft 215 of the second electromagnetic clutch, its driven gear meshes with the driving gear of the PTO shift gear set 203, and the shaft where the driven gear of the PTO shift gear set 203 is located is the PTO power output shaft.

[0045] In the configuration of the power transmission gearbox 2, six driving modes can be realized, as follows:

[0046] (1) Single-motor driving mode

[0047] Only the first motor 10 is working. The PTO shift gear set 203 is in a disengaged state, the shift gear set 202 is in an engaged state, the first electromagnetic clutch 206 is in a disengaged state, the second electromagnetic clutch 212 is in a disengaged state, and the third electromagnetic clutch 216 is in a disengaged state. The power battery 6 supplies power to the first motor 10. The power of the first motor 10 is transmitted to the rear wheels through the eighth gear set 219, the ninth gear set 220, the shift gear set 202, and the first gear set 201. At this time, no power is transmitted to the PTO. The driving walking speed can be switched between high and low by changing the driving gear of the shift gear set 202.

[0048] (2) Engine drive mode

[0049] Only the engine 8 is working. The PTO shift gear set 203 is in a disengaged state, the shift gear set 202 is in an engaged state, the first electromagnetic clutch 206 is in a disengaged state, the second electromagnetic clutch 212 is in a disengaged state, and the third electromagnetic clutch 216 is in an engaged state. The power of the engine 8 is transmitted to the rear wheels through the fourth gear set 209, the fifth gear set 211, the seventh gear set 217, the shift gear set 202, and the first gear set 201. At this time, no power is transmitted to the PTO. The driving walking speed can be switched between high and low by changing the driving gear of the shift gear set 202.

[0050] (3) Dual-motor coupled drive mode

[0051] Only the first motor 10 and the second motor 3 are working. The PTO shift gear set 203 is in a disengaged state, the shift gear set 202 is in an engaged state, the first electromagnetic clutch 206 is in an engaged state, the second electromagnetic clutch 212 is in a disengaged state, and the third electromagnetic clutch 216 is in an engaged state. The power battery 6 supplies power to the first motor 10 and the second motor 3. The power of the first motor 10 is torque-coupled with the power of the second motor 3 after passing through the eighth gear set 219, the ninth gear set 220, the third gear set 207, the second gear set 205, the fifth gear set 211, and the seventh gear set 217. The coupled power is transmitted to the rear wheels through the shift gear set 202 and the first gear set 201. At this time, no power is transmitted to the PTO. The driving walking speed can be switched between high and low by changing the driving gear of the shift gear set 202.

[0052] (4) Engine-motor parallel drive mode

[0053] Only the first motor 10 and the engine 8 are working. The PTO shift gear set 203 is in a disengaged state, the shift gear set 202 is in an engaged state, the first electromagnetic clutch 206 is in a disengaged state, the second electromagnetic clutch 212 is in a disengaged state, the third electromagnetic clutch 216 is in an engaged state. The power battery 6 supplies power to the first motor 10. The power of the first motor 10 is torque-coupled with the power of the engine 8 after passing through the eighth gear set 219 and the ninth gear set 220 and the power of the engine 8 after passing through the fourth gear set 209, the fifth gear set 211, and the seventh gear set 217. The coupled power is transmitted to the rear wheels through the shift gear set 202 and the first gear set 201. At this time, no power is transmitted to the PTO. The driving walking speed can be switched between high and low by changing the driving gear of the shift gear set 202.

[0054] (5) Driving and charging mode

[0055] Only the first motor 10, the second motor 3, and the engine 8 are working. The PTO shift gear set 203 is in a disengaged state, the shift gear set 202 is in an engaged state, the first electromagnetic clutch 206 is in an engaged state, the second electromagnetic clutch 212 is in a disengaged state, the third electromagnetic clutch 216 is in a disengaged state. The power of the engine 8 drives the second motor 3 to generate electricity to supply power to the first motor 10 and the power battery 6 through the fourth gear set 209, the second gear set 205, and the third gear set 207. The power of the first motor 10 is transmitted to the rear wheels through the eighth gear set 219, the ninth gear set 220, the shift gear set 202, and the first gear set 201. At this time, no power is transmitted to the PTO. The driving walking speed can be switched between high and low by changing the driving gear of the shift gear set 202.

[0056] (6) PTO operation mode

[0057] Only the first motor 10 and the engine 8 are working. The PTO shift gear set 203 is in an engaged state, the shift gear set 202 is in an engaged state, the first electromagnetic clutch 206 is in a disengaged state, the second electromagnetic clutch 212 is in an engaged state, the third electromagnetic clutch 216 is in a disengaged state. The power battery 6 supplies power to the first motor 10. The power of the first motor 10 is transmitted to the rear wheels through the eighth gear set 219, the ninth gear set 220, the shift gear set 202, and the first gear set 201. The power of the engine 8 is transmitted to the PTO through 209, the sixth gear set 214, and the PTO shift gear set 203. The high and low speed two-speed output can be realized by switching the position of the driving gear of the shift gear set 202, and the two standard PTO output speeds of 540 rpm and 720 rpm can be realized by switching the gear position of the PTO shift gear set 203.

[0058] As Figure 3 shown, a hybrid tractor drive system and mode switching strategy includes the following steps:

[0059] The vehicle controller 5 collects parameters such as vehicle speed, battery SOC, PTO load request, and braking signal in real time, and dynamically selects the most suitable driving mode in combination with the preset priority and operating condition judgment logic. During mode switching, through the sequential control of the electromagnetic clutch and the gradual change processing of the torque output of the motor / engine, the driving process is ensured to be smooth and continuous.

[0060] When the power demand Preq is lower than the rated output of a single motor P drive and the battery SOC > 20%, the single-motor drive mode is selected; when the power demand Preq is lower than the rated output of a single motor P drive and the battery SOC < 20%, the driving mode for on-road charging is selected; when the power demand Preq is higher than the rated output of a single motor P drive and lower than the rated output of the engine P engine, the engine drive mode is selected; when the power demand Preq is higher than the rated output of the engine P engine and the battery SOC > 20%, the dual-motor coupling drive mode is selected; when the power demand Preq is higher than the rated output of the engine P engine and the battery SOC < 20%, the engine-motor parallel drive mode is selected; when the PTO load is activated, the system enters the PTO operation mode, and the engine 8 supplies energy to the PTO, and the first motor 10 is responsible for driving.

[0061] In the deceleration or braking state, the vehicle controller 5 controls the second motor 3 to enter the regenerative braking mode to recover kinetic energy, which is converted into electrical energy and stored in the battery 6.

[0062] In the driving mode for on-road charging, the engine 8 drives the second motor 3 to generate electricity, and the vehicle controller 5 adjusts the engine load according to the battery SOC: when SOC < 20%, the engine 8 operates in the high-efficiency area with 80% load; when SOC > 80%, the engine 8 idles or suspends power generation to prevent energy waste.

[0063] In the engine-motor parallel drive mode, the system optimally distributes the torque output of the engine and the first motor based on the efficiency MAP: the engine 8 is the basic drive and preferentially operates in the high thermal efficiency area, and the first motor 10 provides high-load compensation.

[0064] In the dual-motor coupling drive mode, the system optimally distributes the torque output of the first motor and the second motor based on the efficiency MAP: the first motor 10 is the basic drive, and the second motor 3 provides high-load compensation.

[0065] In the PTO operation mode, by independently controlling the electromagnetic clutch two 212, the power of the engine 8 is directed to the PTO, and the first motor 10 independently drives the rear wheels to avoid power competition.

[0066] The above embodiments are only used to illustrate the invention patent and are not intended to limit the invention patent. Those of ordinary skill in the relevant technical field can also make various changes and modifications without departing from the essence and scope of the invention patent. Therefore, all equivalent technical solutions also fall within the scope of the invention patent, and the scope of patent protection of the invention patent shall be defined by the claims. The content not described in detail in this specification belongs to the well-known prior art of those skilled in the art.

Claims

1. A hybrid tractor drive system, characterized in that, Comprising: A first motor (10), a second motor (3), an engine (8), a first motor controller (9), a second motor controller (4), an engine controller (7), and a power transmission gearbox (2). The first motor (10), the second motor (3), and the engine (8) are respectively installed at the power input shaft end of the power transmission gearbox (2); The control system includes a first motor controller (9), a second motor controller (4), an engine controller (7), and a vehicle controller (5). The vehicle controller (5) communicates with the first motor controller (9), the second motor controller (4), the engine controller (7), and the power battery (6) via a CAN bus, and is used to coordinately control the operating states of the motors and the engine.

2. The hybrid tractor drive system according to claim 1, wherein The first motor (10) and the second motor (3) are AC motors, and the first motor controller (9) and the second motor controller (4) are both AC motor controllers. Among them, the first motor (10) and the engine (8) are mainly used for driving functions, and the second motor (3) has both driving and power generation functions. When the second motor (3) is in the driving working state, the first motor (10) and the second motor (3) are powered by the power battery (6). When the second motor (3) is in the power generation state, the engine (8) drives the second motor (3) to generate electricity, and the generated electric energy is used to supply power to the first motor (10).

3. A hybrid tractor drive system according to claim 2, characterized in that, The power transmission gearbox (2) includes: a first gear set (201), a shift gear set (202), a PTO shift gear set (203), a right half shaft of electromagnetic clutch one (204), a second gear set (205), an electromagnetic clutch one (206), a third gear set (207), a left half shaft of electromagnetic clutch one (208), a fourth gear set (209), a left half shaft of electromagnetic clutch two (210), a fifth gear set (211), an electromagnetic clutch two (212), a left half shaft of electromagnetic clutch three (213), a sixth gear set (214), a right half shaft of electromagnetic clutch two (215), an electromagnetic clutch three (216), a seventh gear set (217), a right half shaft of electromagnetic clutch three (218), an eighth gear set (219), and a ninth gear set (220); Among them, the output shaft of the first motor (10) is connected to the driving gear of the eighth gear set (219), and the driving gear of the ninth gear set (220) meshes with the driven gear of the eighth gear set (219); the driving gears of the shifting gear set (202) and the seventh gear set (217) mesh with the driven gear of the ninth gear set (220), and the driven gear of the seventh gear set (217) is connected to the right half shaft of the electromagnetic clutch three (218); the driving gear of the first gear set (201) meshes with the driven gear of the shifting gear set (202), and the shaft where its driven gear is located is the rear wheel power output shaft; the output shaft of the second motor (3) is connected to the driving gear of the third gear set (207), and its driven gear is connected to the left half shaft of the electromagnetic clutch one (208); the output shaft of the engine (8) is connected to the driving gear of the fourth gear set (209), and its driven gear meshes with the driving gears of the second gear set (205), the fifth gear set (211) and the left half shaft of the electromagnetic clutch two (210) respectively; the driven gear of the second gear set (205) is connected to the right half shaft of the electromagnetic clutch one (204), and the driven gear of the fifth gear set (211) is connected to the left half shaft of the electromagnetic clutch three (213); the driving gear of the sixth gear set (214) is connected to the right half shaft of the electromagnetic clutch two (215), and its driven gear meshes with the driving gear of the PTO shifting gear set (203), and the shaft where the driven gear of the PTO shifting gear set (203) is located is the PTO power output shaft.

4. A hybrid tractor drive system according to claims 1-3, characterized in that, The power transmission gearbox (2) supports six driving modes, including: Mode 1: The first motor (10) works, the shifting gear set (202) meshes, the PTO shifting gear set (203) disengages, the electromagnetic clutch one (206) disengages, the electromagnetic clutch two (212) disengages, the electromagnetic clutch three (216) disengages, and the power of the first motor (10) is transmitted to the rear wheels through the eighth gear set (219), the ninth gear set (220), the shifting gear set (202), and the first gear set (201). At this time, no power is transmitted to the PTO. Mode 2: The engine (8) works, the shifting gear set (202) meshes, the PTO shifting gear set (203) disengages, the electromagnetic clutch one (206) disengages, the electromagnetic clutch two (212) disengages, the electromagnetic clutch three (216) engages, and the power of the engine (8) is transmitted to the rear wheels through the fourth gear set (209), the fifth gear set (211), the seventh gear set (217), the shifting gear set (202), and the first gear set (201). At this time, no power is transmitted to the PTO. Mode Three: The first motor (10) and the second motor (3) operate, the shift gear set (202) is engaged, the PTO shift gear set (203) is disengaged, the first electromagnetic clutch (206) is engaged, the second electromagnetic clutch (212) is disengaged, the third electromagnetic clutch (216) is engaged. The power of the first motor (10) passes through the eighth gear set (219) and the ninth gear set (220), and then torque-couples with the power of the second motor (3) passing through the third gear set (207), the second gear set (205), the fifth gear set (211), and the seventh gear set (217). The coupled power is transmitted to the rear wheels through the shift gear set (202) and the first gear set (201). At this time, no power is transmitted to the PTO. Mode Four: The first motor (10) and the engine (8) operate, the shift gear set (202) is engaged, the PTO shift gear set (203) is disengaged, the first electromagnetic clutch (206) is disengaged, the second electromagnetic clutch (212) is disengaged, the third electromagnetic clutch (216) is engaged. The power of the first motor (10) passes through the eighth gear set (219) and the ninth gear set (220), and then torque-couples with the power of the engine (8) passing through the fourth gear set (209), the fifth gear set (211), and the seventh gear set (217). The coupled power is transmitted to the rear wheels through the shift gear set (202) and the first gear set (201). At this time, no power is transmitted to the PTO. Mode Five: The first motor (10), the second motor (3), and the engine (8) operate, the shift gear set (202) is engaged, the PTO shift gear set (203) is disengaged, the first electromagnetic clutch (206) is engaged, the second electromagnetic clutch (212) is disengaged, the third electromagnetic clutch (216) is disengaged. The power of the engine (8) drives the second motor (3) to generate electricity through the fourth gear set (209), the second gear set (205), and the third gear set (207). The power of the first motor (10) is transmitted to the rear wheels through the eighth gear set (219), the ninth gear set (220), the shift gear set (202), and the first gear set (201). At this time, no power is transmitted to the PTO. Mode Six: The first motor (10) and the engine (8) operate, the shift gear set (202) is engaged, the PTO shift gear set (203) is engaged, the first electromagnetic clutch (206) is disengaged, the second electromagnetic clutch (212) is engaged, the third electromagnetic clutch (216) is disengaged. The power of the first motor (10) is transmitted to the rear wheels through the eighth gear set (219), the ninth gear set (220), the shift gear set (202), and the first gear set (201). The power of the engine (8) is transmitted to the PTO through (209), the sixth gear set (214), and the PTO shift gear set (203).

5. A hybrid tractor drive system according to claim 4, characterized in that, The shift gear set (202) can achieve two-speed output of high speed and low speed by switching the position of the driving gear. The PTO shift gear set (203) can achieve two standard PTO output speeds of 540 rpm and 720 rpm by switching the gear position.

6. A driving mode switching method for a hybrid tractor, applied to a hybrid tractor drive system as described in claims 1-5, characterized in that, Including: When the power demand P req is lower than the rated output P_drive of a single motor and the battery SOC > 20%, the system enters the single-motor drive mode; When the power demand P req is lower than the rated output P_drive of a single motor and the battery SOC < 20%, the system enters the driving mode with on-board charging; When the power demand P req is higher than the rated output P_drive of a single motor and lower than the rated output P_engine of the engine, the system enters the engine drive mode.

7. A method for switching the driving mode of a hybrid tractor according to claim 6, characterized in that, Also including: When the power demand Preq is higher than the rated output of the engine P engine and the battery SOC > 20%, the system enters the dual-motor coupled drive mode. When the power demand Preq is higher than the rated output P of the engine and the battery SOC < 20%, the system enters the engine-motor parallel drive mode; When the PTO load is activated, the system enters the PTO operation mode, and the engine (8) supplies energy to the PTO, while the first motor (10) provides the driving force for the whole vehicle.

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