Power control system and control method for a hybrid work vehicle

Abstract

This invention relates to a power control system and control method for a hybrid power vehicle, comprising a control system, a main drive system, a power auxiliary system, and a working system. A parallel mechanical coupling channel and a hydraulic coupling channel are provided between the main power unit and the ISG motor. The mechanical coupling channel includes an engine decoupling clutch, and the hydraulic coupling channel includes first and second reversible hydraulic presses and a closed hydraulic circuit. This invention enables the ISG motor to drive the main working pump during pure electric operation while the vehicle is parked. When the engine engages, power is pre-transmitted through the hydraulic coupling channel while the clutch is disengaged. Subsequently, the mechanically transmitted torque is gradually increased while the hydraulically transmitted power is decreased. Simultaneously, the ISG motor compensates for the input torque deviation of the main working pump, achieving continuous power transfer and improving the smoothness of power switching and the continuity of operation.

Description

Technical Field

[0001] This invention relates to the field of power control for hybrid special-purpose vehicles, and specifically to a power control system and control method for hybrid special-purpose vehicles. Background Technology

[0002] When operating while parked, hybrid insulated boom trucks typically require a hydraulic pump driven by an electric motor or engine to provide hydraulic power for the boom's lifting, extension, slewing, and bucket leveling mechanisms. To reduce noise and emissions in energized working areas, the vehicle usually prioritizes pure electric operation using a power battery and electric motor, supplementing power or generating electricity when the power battery's output is insufficient.

[0003] The transition of an engine from a stopped state to a stable output state involves processes such as starting, acceleration, speed matching, and power engagement. During engine power engagement, if the speed or torque on the engine side and the hydraulic pump side cannot be continuously matched, it can easily cause a decrease, sudden increase, or fluctuation in the hydraulic pump input torque, which in turn can lead to changes in boom movement speed, vibration, or even short-term pauses.

[0004] Current power input methods typically rely on electronic controllers to separately regulate engine torque, clutch pressure, and motor torque. Factors such as control signal delays, changes in clutch friction characteristics, hydraulic system leaks, oil temperature variations, and sudden load changes can lead to torque overlap or torque gaps between multiple power sources. Furthermore, when the control power supply or execution pressure is abnormal, multiple power transmission channels may fail simultaneously.

[0005] For insulated boom trucks carrying workers in the bucket, the continuity of hydraulic power during stationary operations directly affects the safety of boom leveling, retraction, and lowering. Therefore, a power system is needed that can maintain continuous hydraulic pump power during engine engagement and disengagement, and retain operational power even in the event of partial control function malfunctions.

[0006] The purpose of this invention is to design a power control system and control method for a hybrid power vehicle to address the problems existing in the prior art. Summary of the Invention

[0007] In view of the problems existing in the prior art, the present invention provides a power control system and control method for a hybrid power operation vehicle, which can effectively solve at least one of the problems existing in the prior art.

[0008] To achieve the above objectives, the present invention provides a power control system for a hybrid power vehicle, including a control system, a main drive system, a power assistance system, and a working system.

[0009] The control system is used to acquire the vehicle operating status, working system load status, engine operating status, ISG motor operating status, power battery status, and power coupling unit operating status, and to perform joint control and power distribution on the main drive system, power assistance system, and working system.

[0010] The overall drive system includes a power unit, a power coupling unit, a power distribution unit, and a drive unit. The power unit includes an engine, and the drive unit includes the vehicle's drive axle.

[0011] The power assistance system includes an ISG motor and a power battery electrically connected to the ISG motor. The ISG motor can operate in electric mode or power generation mode.

[0012] The working system includes a main working pump, which receives power from at least one of the main drive system and the power assist system to drive the vehicle's working device.

[0013] The power coupling unit is located between the main power unit and the power assistance system, and includes a mechanical coupling channel and a hydraulic coupling channel connected in parallel.

[0014] The mechanical coupling channel includes an engine decoupling clutch, used to selectively establish or disconnect the mechanical power transmission between the engine and the power transmission shaft where the ISG motor is located.

[0015] The hydraulic coupling channel includes a first reversible hydraulic press, a second reversible hydraulic press, and a closed hydraulic circuit connecting the two. The first reversible hydraulic press is driven to the engine, and the second reversible hydraulic press is driven to the power transmission shaft of the ISG motor, so that the hydraulic coupling channel spans the engine decoupling clutch and enables power transmission between the engine side and the ISG motor side when the engine decoupling clutch is in the disengaged state.

[0016] Therefore, when the engine decoupling clutch disengages, the engine power can first be flexibly connected to the ISG motor side and working system through the hydraulic coupling channel; after the speeds on both sides of the engine decoupling clutch meet the engagement conditions, the power transmission of the mechanical coupling channel is gradually established, thereby realizing the continuous transfer of hydraulic power to mechanical power.

[0017] The power distribution unit includes a power take-off (PTO) and a working PTO engagement mechanism. The PTO is connected to the power auxiliary system, the drive unit, and the working system. The working PTO engagement mechanism is used to selectively connect or disconnect the power transmission between the PTO and the main working pump.

[0018] Furthermore, the engine has an engine output shaft, the ISG motor is mounted on the ISG working shaft, and the engine decoupling clutch is located between the engine output shaft and the ISG working shaft. A first reversible hydraulic press is driven by the engine output shaft located on the engine side of the engine decoupling clutch, and a second reversible hydraulic press is driven by the ISG working shaft located on the other side of the engine decoupling clutch.

[0019] The overall drive system may also include an AMT transmission, a travel clutch, and a reduction mechanism. The AMT transmission is located between the ISG working shaft and the power take-off input end, the travel clutch is located between the power take-off output end and the drive axle, and the reduction mechanism is located between the power take-off working end and the main working pump.

[0020] When the vehicle is in motion, the driving clutch engages and the power take-off engagement mechanism disengages, allowing the power output from at least one of the engine and ISG motor to be transmitted to the drive axle via the AMT gearbox, power take-off, and driving clutch.

[0021] When the vehicle is in the parking operation state, the driving clutch is disengaged and the working power take-off engagement mechanism is engaged, so that the power output of at least one of the engine and ISG motor is transmitted to the main working pump through the AMT gearbox, power take-off and reduction mechanism.

[0022] Furthermore, the first reversible hydraulic press has a first working port and a second working port, and the second reversible hydraulic press has a third working port and a fourth working port. The first working port is connected to the third working port through a first working pipeline, and the second working port is connected to the fourth working port through a second working pipeline, thereby forming a closed hydraulic circuit.

[0023] A closed-loop hydraulic circuit may also include a replenishing pump, a replenishing check valve, and a pressure limiting assembly. The replenishing pump is used to replenish hydraulic oil to the low-pressure working lines of the closed-loop hydraulic circuit, and the pressure limiting assembly is used to limit the working pressure difference between the first and second working lines. The closed-loop hydraulic circuit may also be equipped with an oil cooling and filtration assembly and a pressure detection device.

[0024] The first reversible hydraulic press is preferably a hydraulic press with adjustable displacement. The control system continuously adjusts the power transmitted through the hydraulic coupling channel by changing the hydraulic flow rate in the closed hydraulic circuit and the output torque of the second reversible hydraulic press by adjusting the displacement of the first reversible hydraulic press.

[0025] Furthermore, the power control system may also include an independent electro-hydraulic control valve assembly, which includes a pilot pressure source, a first proportional control valve for adjusting the engagement pressure of the engine decoupling clutch, and a second proportional control valve for adjusting the displacement of the first reversible hydraulic press.

[0026] The first proportional control valve and the second proportional control valve receive control signals from the control system, thereby enabling the mechanical transmission torque of the engine decoupling clutch and the hydraulic transmission torque of the hydraulic coupling channel to be continuously and independently adjusted.

[0027] Preferably, the engine decoupling clutch adopts a pressure loss separation structure, which returns to the separation state when the first proportional control valve loses power or the pilot pressure is insufficient; the first reversible hydraulic press adopts a power loss return-to-zero structure, which returns to the zero displacement state when the corresponding control branch loses power, so as to reduce the risk of engine power unexpectedly entering the working system under abnormal conditions.

[0028] Furthermore, the power control system may also include a sensor assembly, which includes a first speed detection device for detecting the engine output shaft speed, a second speed detection device for detecting the ISG working shaft speed, an engagement pressure detection device for detecting the engagement pressure of the engine decoupling clutch, a displacement detection device for detecting the displacement of the first reversible hydraulic press, a circuit pressure detection device for detecting the working pressure difference of the closed hydraulic circuit, and a working load detection device for detecting the working status of the main working pump.

[0029] The control system can determine the required torque of the working system based on the working pressure and displacement of the main working pump, determine the hydraulic transmission torque of the hydraulic coupling channel based on the working pressure difference of the closed hydraulic circuit and the displacement of the second reversible hydraulic press, and determine the mechanical transmission torque of the mechanical coupling channel based on the engagement pressure of the engine decoupling clutch, the speed difference between the two sides and the engagement state.

[0030] Based on this, the control system determines the target torque of the ISG motor according to the deviation between the required torque of the working system and the sum of the mechanically transmitted torque and the hydraulically transmitted torque, so that the ISG motor can dynamically compensate the input torque of the main working pump during the engine power switching process.

[0031] The present invention also provides a power control method applied to the above-mentioned power control system, wherein the hybrid power vehicle includes an engine, an ISG motor, a power coupling unit, a power distribution unit, a power battery, and a main working pump; The engine and the ISG motor transmit power through the power coupling unit, which includes a mechanical coupling channel and a hydraulic coupling channel arranged in parallel. The mechanical coupling channel includes an engine decoupling clutch disposed between the engine and the ISG motor; The hydraulic coupling channel includes a first reversible hydraulic press, a second reversible hydraulic press, and a closed hydraulic circuit connecting the first reversible hydraulic press and the second reversible hydraulic press. The first reversible hydraulic press is driven to the engine output shaft of the engine, and the second reversible hydraulic press is driven to the ISG working shaft where the ISG motor is located. The power distribution unit is used to transmit the power output from at least one of the engine and the ISG motor to the main working pump, and the power battery is electrically connected to the ISG motor through a high-voltage DC bus; The power control method includes: S100. In the pure electric operation state of parking, the engine decoupling clutch is disengaged and the hydraulic coupling channel stops transmitting power. The power battery supplies power to the ISG motor so that the ISG motor drives the main working pump through the power distribution unit. S200. When the engine intervention conditions are met, keep the engine decoupling clutch disengaged and start the engine. Adjust the displacement of the first reversible hydraulic press so that the power output by the engine is transmitted to the ISG working shaft in sequence through the first reversible hydraulic press, the closed hydraulic circuit and the second reversible hydraulic press, so as to establish the hydraulic power transmission of the hydraulic coupling channel. S300. When the speed difference between the two sides of the engine decoupling clutch meets the engagement condition, the mechanical transmission torque of the engine decoupling clutch is gradually increased, and the hydraulic transmission power of the hydraulic coupling channel is gradually decreased, so that the power output by the engine is gradually transferred from the hydraulic coupling channel to the mechanical coupling channel. S400. During the power transfer process, the output torque of the ISG motor is adjusted according to the required torque of the main working pump, the mechanical transmission torque of the mechanical coupling channel, and the hydraulic transmission torque of the hydraulic coupling channel to compensate for the input torque deviation of the main working pump. S500: After the engine decoupling clutch is fully engaged, the hydraulic coupling channel stops transmitting power, and the engine drives the main working pump through the mechanical coupling channel and the power distribution unit.

[0032] The engine intervention conditions can be determined based on at least one of the following: the main working pump's required power, the ISG motor's allowable output torque, the power battery's state of charge, and the power battery's allowable discharge power. For example, the engine intervention conditions can be determined to be met when the main working pump's required power exceeds the pure electric operating capacity, the ISG motor reaches a preset output limit, the power battery's state of charge is lower than a preset value, or the power battery's allowable discharge power is insufficient.

[0033] During the engine decoupling clutch engagement process, the control system can gradually increase the mechanical transmission torque according to the clutch engagement pressure, and simultaneously reduce the displacement of the first reversible hydraulic press, so that the hydraulic transmission torque is gradually reduced, thereby continuously transferring the power source from the hydraulic coupling channel to the mechanical coupling channel.

[0034] When the sum of the mechanically transmitted torque and the hydraulically transmitted torque is less than the torque required by the main working pump, the ISG motor increases the electric torque; when the sum of the two is greater than the torque required by the main working pump, the ISG motor reduces the electric torque or enters the generator state, so that the input torque of the main working pump is maintained within the preset fluctuation range.

[0035] When the engine is driving stably, if the engine has excess power and the power battery is allowed to charge, the control system can control the ISG motor to enter the power generation state, converting the excess mechanical power of the engine into electrical energy and storing it in the power battery; when the engine output capacity is insufficient, the ISG motor can enter the electric assist state, driving the main working pump together with the engine.

[0036] Furthermore, when switching from engine-driven operation to parked pure electric operation, the control system first establishes electric compensation torque with the ISG motor. While the engine decoupling clutch remains engaged, the first reversible hydraulic press gradually increases its displacement from zero to re-establish hydraulic transmission torque. Subsequently, the engagement pressure of the engine decoupling clutch is gradually reduced, causing the mechanical transmission torque to decrease progressively. The output torque of the ISG motor is adjusted based on the changes in both mechanical and hydraulic transmission torque. After the engine decoupling clutch is fully disengaged, the ISG motor drives the main working pump, which then returns the first reversible hydraulic press to zero displacement and stops the engine.

[0037] Furthermore, when an abnormality is detected in the hydraulic coupling channel, engine decoupling clutch, or working power take-off transmission path, the control system stops the current power switching process and keeps or returns the engine decoupling clutch to the disengaged state, so that the first reversible hydraulic press returns to the zero displacement state.

[0038] When the engine or power coupling unit fails, but the power battery and ISG motor are still able to work normally, the control system can enter a pure electric degraded operation state. The ISG motor drives the main working pump within the allowable discharge power range of the power battery and limits the maximum output power of the working system and / or the operation of the working device to meet the needs of safe stopping, recovery or reset of the vehicle.

[0039] Therefore, the present invention provides the following effects and / or advantages: This invention establishes a mechanical coupling channel and a hydraulic coupling channel in parallel between the engine and the ISG motor. When the engine engages, power is first established using the hydraulic coupling channel while the engine decoupling clutch remains disengaged, and then the mechanical coupling channel gradually takes over the power, thereby reducing power interruption and clutch shock caused by direct mechanical engine engagement.

[0040] After the speed difference on both sides of the engine decoupling clutch meets the engagement condition, this invention gradually increases the transmitted torque of the mechanical coupling channel while gradually decreasing the transmitted power of the hydraulic coupling channel, causing the engine power to gradually transfer from the hydraulic coupling channel to the mechanical coupling channel. During the process of increasing mechanical transmitted torque and decreasing hydraulic transmitted torque, the ISG motor dynamically compensates for the deviation between the two and the torque required by the main working pump, which helps to maintain the continuity of the input power of the working system and reduce the speed and load fluctuations of the working device during the power source switching process.

[0041] The hydraulic coupling channel is mainly responsible for the flexible adjustment of power intervention, speed coordination and power transfer. After the engine is stably engaged, the mechanical coupling channel is mainly used to transmit power, thus taking into account both the smoothness of power switching and the transmission efficiency under stable operating conditions.

[0042] The ISG motor combines electric operation, power compensation, power assist, and power generation functions, enabling the power battery, engine, and working system to coordinate according to actual power demand, thereby improving the overall energy efficiency of the vehicle.

[0043] By controlling the engine decoupling clutch underpressure separation, hydraulic press power failure return to zero, and pure electric degradation, unexpected power transmission can be suppressed when the power coupling device malfunctions, while retaining limited pure electric operation capability, thus improving the fault safety of hybrid power vehicles.

[0044] This invention enables the main working pump to be driven by the ISG motor during pure electric operation while the vehicle is parked. When the engine is engaged, power is pre-transmitted through the hydraulic coupling channel while the clutch is disengaged. Subsequently, the mechanically transmitted torque is gradually increased and the hydraulically transmitted power is reduced. At the same time, the ISG motor compensates for the input torque deviation of the main working pump, thereby achieving continuous power transfer and improving the smoothness of power switching and the continuity of operation. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the control system according to Embodiment 1 of the present invention.

[0046] Figure 2 This is a structural diagram of the dynamic coupling unit in Embodiment 1 of the present invention.

[0047] Figure 3 This is a structural diagram of the independent electro-hydraulic control valve assembly in Embodiment 1 of the present invention.

[0048] Figure 4 This is a transmission route diagram of the control system in pure electric mode in Embodiment 1 of the present invention.

[0049] Figure 5 This is a transmission route diagram showing the engine connected via a hydraulic coupling channel in Embodiment 1 of the present invention.

[0050] Figure 6 This is one of the transmission route diagrams for the engine decoupling clutch engagement process in Embodiment 1 of the present invention.

[0051] Figure 7 This is the second transmission route diagram for the engine decoupling clutch engagement process in Embodiment 1 of the present invention.

[0052] Figure 8 This is a transmission route diagram of the control system in engine drive mode in Embodiment 1 of the present invention.

[0053] Figure 9 This is a diagram showing the energy transfer route of the ISG motor during reverse charging in Embodiment 1 of the present invention.

[0054] Figure 10 This is a transmission route diagram of the control system in hybrid driving mode in Embodiment 1 of the present invention.

[0055] Figure 11 This is a structural diagram of the dynamic coupling unit in Embodiment 2 of the present invention.

[0056] Figure 12 This is a structural diagram of the independent electro-hydraulic control valve group in Embodiment 2 of the present invention.

[0057] In the picture: 100. Control system; 110. Vehicle controller; 120. Engine controller; 130. Motor controller; 140. Battery management system; 150. Transmission controller; 200. Main drive system; 210. Engine; 211. Engine output shaft; 212. Engine starting device; 220. Drive axle; 230. Engine decoupling clutch; 231. Hydraulic actuator; 240. First reversible hydraulic press; 241. First displacement actuator; 250. Second reversible hydraulic press; 251. Second displacement actuator; 260. Closed hydraulic circuit; 261. First working pipeline; 262. Second working pipeline; 263. Make-up oil pump; 264. Make-up oil check valve; 265. Pressure limiting assembly; 266. Oil cooling and filtration assembly; 267. Hydraulic oil tank; 268. 270. Pressure sensor; 280. Power take-off; 290. AMT gearbox; 201. Travel clutch; 312. Reduction mechanism; 323. Power auxiliary system; 330. ISG motor; 341. ISG working shaft; 320. Power battery; 321. High voltage DC bus; 400. Working system; 410. Main working pump; 500. Independent electro-hydraulic control valve assembly; 510. Pilot pressure source; 520. First proportional control valve; 530. Second proportional control valve; 540. Third proportional control valve; 550. Displacement switching valve; 600. Sensor assembly; 610. First speed detection device; 620. Second speed detection device; 630. Engagement pressure detection device; 640. Displacement detection device; 650. Circuit pressure detection device; 660. Working load detection device. Detailed Implementation

[0058] The technical solution of the present invention will be further described below with reference to specific embodiments. It should be noted that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Without departing from the concept of the present invention, any equivalent substitutions or conventional adjustments made by those skilled in the art to the specific forms, connection methods, and control parameters of the components should be considered as implementation forms of the technical solution of the present invention.

[0059] Example 1 This embodiment uses a hybrid insulated bucket truck as an example for illustration. Besides insulated bucket trucks, this invention can also be applied to aerial work platforms, truck-mounted cranes, emergency rescue vehicles, sanitation vehicles, and other hybrid-powered work vehicles that require the main working pump 410 to drive the working device while parked.

[0060] like Figure 1-10 As shown, the power control system includes a control system 100, a main drive system 200, a power auxiliary system 300, and a working system 400.

[0061] The control system 100 is used to acquire the vehicle operating status, the load status of the working system 400, the operating status of the engine 210, the operating status of the ISG motor 310, the status of the power battery 320, the status of the engine decoupling clutch 230, and the status of the hydraulic coupling channel, and to perform power mode judgment, power distribution and power switching control based on the above status. The controllers can exchange information with each other through the vehicle bus.

[0062] The control system 100 may include a vehicle controller 110 and communication devices such as an engine controller 120, an electric motor controller 130, a battery management system 140, a transmission controller 150, and an electro-hydraulic controller. Alternatively, it may be implemented by an integrated controller with corresponding functions. The controllers can exchange information via the vehicle bus.

[0063] The overall drive system 200 includes an engine 210, a power coupling unit, a power take-off unit 270, an AMT transmission 280, a service clutch 281, a reduction gear 290, and a drive axle 220, which is used to transmit power to the vehicle wheels.

[0064] The engine 210 has an engine output shaft 211 and can be started by a separate engine starter 212.

[0065] The power assistance system 300 includes an auxiliary power unit and an energy storage unit, namely an ISG motor 310 and a power battery 320. The ISG motor 310 is mounted on the ISG working shaft 311 and exchanges electrical energy with the power battery 320 through a high-voltage DC bus 321. The ISG motor 310 can output mechanical power in electric mode and can also absorb mechanical power and charge the power battery 320 in generator mode.

[0066] The working system 400 includes a main working pump 410 and a working hydraulic circuit supplied by the main working pump 410. Taking an insulated boom truck as an example, the working hydraulic circuit can be used to drive the boom luffing cylinder, boom telescopic cylinder, slewing mechanism, bucket leveling mechanism, and other hydraulic actuators. The main working pump 410 is used to receive power from at least one of the engine 210 and the ISG motor 310 and convert mechanical energy into hydraulic energy.

[0067] An engine decoupling clutch 230 is provided between the engine output shaft 211 and the ISG working shaft 311. When the engine decoupling clutch 230 is engaged, a mechanical power transmission is established between the engine output shaft 211 and the ISG working shaft 311; when the engine decoupling clutch 230 is disengaged, the mechanical transmission path between the two is broken.

[0068] The engine decoupling clutch 230 is a wet multi-plate clutch, which includes a clutch hydraulic actuator 231. The control pressure change of the clutch hydraulic actuator 231 is used to change the clamping force between the clutch friction plates, thereby changing the mechanical torque that the engine decoupling clutch 230 can transmit.

[0069] The AMT transmission 280 is connected between the ISG working shaft 311 and the power take-off (PTO) 270. The PTO 270 has a driving output path and a working power take-off path. Its driving output end is connected to the drive axle 220 through a driving clutch 281, and its working power take-off end is connected to the main working pump 410 through a working power take-off engagement mechanism (not shown in the figure) and a reduction mechanism 290.

[0070] Therefore, when the vehicle is in motion, the driving clutch 281 can be engaged and the working power take-off engagement mechanism can be disengaged, so that at least one of the engine 210 and the ISG motor 310 can provide power to the drive axle 220; when the vehicle is parked, the driving clutch 281 can be disengaged and the working power take-off engagement mechanism can be engaged, so that at least one of the engine 210 and the ISG motor 310 can provide power to the main working pump 410.

[0071] The power coupling unit includes a mechanical coupling channel and a hydraulic coupling channel.

[0072] The mechanical coupling channel is mainly formed by the engine decoupling clutch 230. The hydraulic coupling channel includes a first reversible hydraulic press 240 (Figure H1), a second reversible hydraulic press 250 (Figure H2), and a closed hydraulic circuit 260.

[0073] The first reversible hydraulic press 240 is driven to the engine output shaft 211 and is located on the engine side of the engine decoupling clutch 230; the second reversible hydraulic press 250 is driven to the ISG working shaft 311 and is located on the other side of the engine decoupling clutch 230.

[0074] The first reversible hydraulic press 240 and the second reversible hydraulic press 250 are connected through a closed hydraulic circuit 260, so that the hydraulic coupling channel crosses the engine decoupling clutch 230 and is connected in parallel with the mechanical coupling channel formed by the engine decoupling clutch 230.

[0075] When the engine decoupling clutch 230 is disengaged, the engine 210 can still drive the first reversible hydraulic press 240 to work. The first reversible hydraulic press 240 drives the second reversible hydraulic press 250 through the closed hydraulic circuit 260, so that the engine power is transmitted to the ISG working shaft 311 in a hydraulic manner.

[0076] The first reversible hydraulic press 240 has a first working port and a second working port, and the second reversible hydraulic press 250 has a third working port and a fourth working port. The first working port is connected to the third working port through a first working pipe 261, and the second working port is connected to the fourth working port through a second working pipe 262, thereby forming a closed hydraulic circuit 260 in which hydraulic oil circulates between the first reversible hydraulic press 240 and the second reversible hydraulic press 250.

[0077] The closed-loop hydraulic circuit 260 is equipped with a replenishing pump 263, a replenishing check valve 264, and a pressure limiting component 265. The replenishing pump 263 replenishes hydraulic oil to the low-pressure side through two different replenishing check valves 264 according to the pressure status of the first working line 261 and the second working line 262. The pressure limiting component 265 is used to limit the working pressure difference between the two working lines. The closed-loop hydraulic circuit 260 may also be equipped with an oil cooling and filtering component 266 and a hydraulic oil tank 267 to meet the replenishment, cooling, and filtering needs of the hydraulic system.

[0078] The pressure limiting component 265 is connected between the first working pipeline 261 and the second working pipeline 262, and includes a first high-pressure relief valve and a second high-pressure relief valve arranged in opposite directions to limit the pressure difference between the first working pipeline 261 and the second working pipeline 262 in the two power transmission directions, respectively. When the working pressure difference of the closed hydraulic circuit 260 exceeds the preset pressure, the corresponding high-pressure relief valve opens, allowing part of the hydraulic oil in the high-pressure working pipeline to flow to the low-pressure working pipeline, thereby protecting the first reversible hydraulic press 240, the second reversible hydraulic press 250, and the working pipelines.

[0079] Pressure sensors 268 can be installed in the first working pipeline 261 and the second working pipeline 262 respectively. The working pressure difference of the closed hydraulic circuit 260 is determined by the pressure difference between the two. Based on the working pressure difference, the displacement and hydraulic efficiency of the second reversible hydraulic press 250, the hydraulic transmission torque output by the second reversible hydraulic press 250 to the ISG working shaft 311 is estimated.

[0080] The closed hydraulic circuit 260 may also be equipped with a temperature sensor (not shown in the figure) to detect the hydraulic oil temperature. The control system 100 can correct the estimated values ​​of the hydraulic press's volumetric efficiency, mechanical efficiency, and hydraulic transmission torque based on the hydraulic oil temperature.

[0081] In this embodiment, the first reversible hydraulic press 240 employs a bidirectional hydraulic pump with adjustable displacement and is equipped with a first displacement actuator 241. The second reversible hydraulic press 250 employs a reversible hydraulic press with a preset working displacement state and a zero displacement or preset minimum displacement state, and is equipped with a second displacement actuator 251. The second displacement actuator 251 is used to switch the second reversible hydraulic press 250 between the preset working displacement state and the zero displacement or preset minimum displacement state. A throttling or damping structure is provided in the control oil circuit of the second displacement actuator 251 to limit the rate of displacement change of the second reversible hydraulic press 250 between the two displacement states.

[0082] When the hydraulic coupling channel does not require effective power transmission, the control system 100 keeps the second reversible hydraulic press 250 in a zero displacement or preset minimum displacement state to reduce the hydraulic flow and reverse torque generated when the second reversible hydraulic press 250 rotates with the ISG working shaft 311. When the hydraulic coupling channel needs to establish power transmission, the control system 100 coordinates and adjusts the displacement of the first reversible hydraulic press 240 and gradually puts the second reversible hydraulic press 250 into a preset working displacement state, so that the hydraulic flow generated by the first reversible hydraulic press 240 gradually matches the hydraulic flow corresponding to the current speed and displacement of the second reversible hydraulic press 250, and establishes a working pressure difference for power transmission on this basis.

[0083] When the second reversible hydraulic press 250 is in a zero displacement or preset minimum displacement state, even if it rotates with the ISG working shaft 311, the theoretical suction and discharge flow rate it generates is reduced to a preset range, thereby reducing the circulating flow rate, working pressure difference and reverse drag torque generated by the second reversible hydraulic press 250 on the ISG working shaft 311 in the closed hydraulic circuit 260.

[0084] When engine 210 engages, the first reversible hydraulic press 240 primarily operates as a pump, converting the mechanical power output by engine 210 into hydraulic power; the second reversible hydraulic press 250 primarily operates as a motor, converting the hydraulic power into mechanical power on the ISG working shaft 311. The high-pressure side and low-pressure side of the first working pipeline 261 and the second working pipeline 262 are determined according to the rotation direction and power transmission direction of the first reversible hydraulic press 240 and the second reversible hydraulic press 250, and are not limited to a fixed working pipeline as the high-pressure side.

[0085] When the first reversible hydraulic press 240 is in a zero-displacement state, the hydraulic coupling channel essentially stops transmitting effective power. The zero-displacement state referred to in this article includes an actual displacement of zero or a minimum displacement state where only permissible leakage and control errors exist, but which does not undertake effective power transmission.

[0086] When the direction of power transmission changes, the first reversible hydraulic press 240 and the second reversible hydraulic press 250 can change their working state according to control requirements to adapt to the bidirectional oil flow in the closed hydraulic circuit 260. The control system 100 determines the current high-pressure side and low-pressure side according to the pressure of the first working pipeline 261 and the second working pipeline 262, and determines the power transmission state of the hydraulic coupling channel according to the pressure difference between the two.

[0087] The power control system also includes an independent electro-hydraulic control valve assembly 500. The independent electro-hydraulic control valve assembly 500 includes a pilot pressure source 510, a first proportional control valve 520, and a second proportional control valve 530.

[0088] The pilot pressure source 510 is connected to the hydraulic actuator of the engine decoupling clutch 230 via the first proportional control valve 520, forming a first control branch for adjusting the engagement pressure of the engine decoupling clutch 230. The control system 100 adjusts the control pressure of the hydraulic actuator of the engine decoupling clutch 230 by changing the control current of the first proportional control valve 520, thereby gradually changing the mechanical transmission torque of the mechanical coupling channel.

[0089] The pilot pressure source 510 is connected to the first displacement actuator 241 of the first reversible hydraulic press 240 via the second proportional control valve 530, forming a second control branch for adjusting the displacement of the first reversible hydraulic press 240. The control system 100 adjusts the position of the swashplate tilt angle, swing angle, or other displacement adjustment mechanism of the first reversible hydraulic press 240 by changing the control current of the second proportional control valve 530, thereby changing the displacement of the first reversible hydraulic press 240 and the transmission power of the hydraulic coupling channel.

[0090] The first proportional control valve 520 and the second proportional control valve 530 respectively receive control signals from the control system 100, so that the engagement pressure of the engine decoupling clutch 230 and the displacement of the first reversible hydraulic press 240 can be independently adjusted under the coordination of the pilot pressure source 510.

[0091] In one specific embodiment, the first proportional control valve 520 is a proportional pressure-reducing relief valve, and the second proportional control valve 530 is a proportional directional valve or a proportional pressure valve. Alternatively, the first proportional control valve 520 and the second proportional control valve 530 may be other electro-hydraulic control valves capable of continuously regulating the corresponding pressure or flow rate.

[0092] The pilot pressure source 510 is connected to the second displacement actuator 251 via the displacement switching valve 550, which is a two-position three-way solenoid directional valve. The pressure port of the displacement switching valve 550 is connected to the pilot pressure source 510, the working port is connected to the second displacement actuator 251, and the return port is connected to the return oil passage.

[0093] When the displacement switching valve 550 is in the first working position, the second displacement actuator 251 is connected to the return oil passage, and the second reversible hydraulic press 250 is in the zero displacement or preset minimum displacement state under the action of the reset mechanism; when the displacement switching valve 550 is in the second working position, the pilot pressure source 510 is connected to the second displacement actuator 251, so that the second reversible hydraulic press 250 enters the preset working displacement state.

[0094] A throttling element is provided in the control oil circuit of the second displacement actuator 251 to limit the operating speed of the second displacement actuator 251, so that the second reversible hydraulic press 250 can smoothly switch between zero displacement or preset minimum displacement state and preset working displacement state.

[0095] Pilot pressure source 510 is used to provide control oil and pilot pressure to the first proportional control valve 520 and the second proportional control valve 530. Pilot pressure source 510 can be provided by the vehicle's existing hydraulic system, or it can be composed of a separately installed pilot pump, accumulator, or other hydraulic source capable of providing stable control pressure. The first proportional control valve 520 adjusts the control pressure acting on the clutch hydraulic actuator 231 according to the control signal from the control system 100, and the second proportional control valve 530 adjusts the control pressure or control oil flow acting on the first displacement actuator 241 of the first reversible hydraulic press 240 according to the control signal from the control system 100, thereby realizing the continuous adjustment of the engagement state of the engine decoupling clutch 230 and the displacement of the first reversible hydraulic press 240, respectively.

[0096] The engine decoupling clutch 230 preferably adopts a pressure loss separation structure. When the first proportional control valve 520 is de-energized or the pilot pressure is insufficient, the clutch hydraulic actuator 231 is depressurized, causing the engine decoupling clutch 230 to return to the disengaged state.

[0097] The first reversible hydraulic press 240 preferably adopts a power-off zero-displacement structure. When the second proportional control valve 530 loses power, the first displacement actuator 241, under the action of the reset mechanism, causes the first reversible hydraulic press 240 to return to the zero displacement state.

[0098] Through the aforementioned independent control structure, the control system 100 can adjust the corresponding actuators according to the actual state of the mechanical coupling channel and the hydraulic coupling channel, respectively.

[0099] The power control system also includes sensor assembly 600.

[0100] The sensor assembly 600 includes a first speed detection device 610, a second speed detection device 620, an engagement pressure detection device 630, a displacement detection device 640, a loop pressure detection device 650, and a working load detection device 660.

[0101] The first speed detection device 610 detects the speed of the engine output shaft 211; the second speed detection device 620 detects the speed of the ISG working shaft 311; the engagement pressure detection device 630 detects the engagement pressure of the engine decoupling clutch 230; the displacement detection device 640 detects the actual displacement of the first reversible hydraulic press 240; the circuit pressure detection device 650 detects the working pressure difference of the closed hydraulic circuit 260; and the working load detection device 660 is used to obtain the working pressure, displacement, or other parameters that reflect the load of the working system of the main working pump 410.

[0102] The control system 100 can determine the required torque of the main working pump 410 based on its working pressure and displacement. The required torque of the main working pump 410 can be calculated according to the correspondence between the pressure difference between the inlet and outlet of the main working pump 410, the displacement of the main working pump 410, and the mechanical efficiency, or it can be determined through a pre-calibrated mapping relationship between pressure, displacement, speed, and required torque.

[0103] The hydraulic transmission torque of the hydraulic coupling channel can be determined based on the working pressure difference of the closed hydraulic circuit 260, the displacement of the second reversible hydraulic press 250, and the mechanical efficiency of the second reversible hydraulic press 250.

[0104] The product of the working pressure difference of the closed hydraulic circuit 260 and the displacement per revolution of the second reversible hydraulic press 250 corresponds to the theoretical output torque of the second reversible hydraulic press 250, and can be corrected by taking into account the hydraulic oil temperature and hydraulic efficiency.

[0105] The mechanical transmission torque of the mechanical coupling channel can be determined based on the engagement pressure of the engine decoupling clutch 230, the effective friction radius of the friction plates, the number of friction plates, the friction coefficient, and the speed difference between the two sides of the clutch. In actual control, the control system 100 can obtain an estimated value of the mechanical transmission torque through a pre-calibrated mapping relationship between clutch engagement pressure, speed difference, oil temperature, and mechanical transmission torque.

[0106] The control system 100 determines the target torque of the ISG motor 310 based on the deviation between the required torque of the main working pump 410 and the sum of the mechanically transmitted torque and the hydraulically transmitted torque. The target torque of the ISG motor 310 can be expressed as the required torque of the main working pump 410 minus the mechanically transmitted torque and the hydraulically transmitted torque, and is corrected by taking into account power transmission losses, speed regulation requirements, and dynamic compensation.

[0107] In the first embodiment, the second reversible hydraulic press 250 is a fixed displacement hydraulic press, with its displacement being a predetermined structural parameter. The control system 100 determines the output torque of the second reversible hydraulic press 250 based on the working pressure difference of the closed hydraulic circuit 260, the displacement of the second reversible hydraulic press 250, and the mechanical efficiency of the second reversible hydraulic press 250. The output torque of the second reversible hydraulic press 250 is positively correlated with the working pressure difference of the closed hydraulic circuit 260 and the displacement of the second reversible hydraulic press 250.

[0108] Furthermore, the control system 100 can obtain the correspondence between the working pressure difference of the closed hydraulic circuit 260, the hydraulic oil temperature, the speed of the second reversible hydraulic press 250 and the actual output torque through experimental calibration, and obtain the hydraulic transmission torque by looking up a table to compensate for theoretical calculation errors caused by hydraulic press leakage, mechanical friction and hydraulic oil temperature changes.

[0109] Therefore, the hydraulic torque can be obtained either by theoretical calculation based on working pressure difference and displacement, or by using a pre-calibrated characteristic mapping relationship.

[0110] When the engine 210, the first reversible hydraulic press 240, the second reversible hydraulic press 250, the ISG motor 310 and the main working pump 410 are equipped with gear transmission mechanisms, AMT gearbox 280, power take-off 270 or reduction mechanism 290 and have different transmission ratios, the control system 100 compares and balances the mechanical transmission torque of the engine decoupling clutch 230, the hydraulic transmission torque of the second reversible hydraulic press 250, the output torque of the ISG motor 310 and the required torque of the main working pump 410 after converting them to the same reference axis according to the corresponding transmission ratio and transmission efficiency.

[0111] The reference shaft is preferably the ISG working shaft 311, but it can also be selected as the engine output shaft 211 or the main working pump 410 input shaft depending on the specific implementation of the control system 100. The mechanical transmission torque, hydraulic transmission torque and ISG motor 310 output torque together satisfy the torque required by the main working pump 410, as mentioned in this article, means that the above torques, after being converted to the same reference shaft through the corresponding transmission ratio and transmission efficiency, satisfy the corresponding dynamic balance relationship.

[0112] When the vehicle enters the parking operation state, the control system 100 detects the vehicle speed, parking brake status, driving clutch 281 status, and operation power take-off engagement mechanism status.

[0113] When the vehicle speed is zero, the parking brake is effective, and the driving clutch 281 is disengaged, the control operation power take-off engagement mechanism is engaged, so that a power transmission path is formed between the power take-off unit 270 and the main working pump 410.

[0114] Combination Figure 4In the pure electric operation mode of parking, the engine decoupling clutch 230 remains disengaged, the first reversible hydraulic press 240 is in a zero displacement state, and the hydraulic coupling channel does not undertake effective power transmission.

[0115] The power battery 320 supplies power to the ISG motor 310, which in turn drives the main working pump 410 through the AMT gearbox 280, power take-off 270, working power take-off engagement mechanism and reduction mechanism 290 in sequence.

[0116] The control system 100 adjusts the speed and output torque of the ISG motor 310 according to the load changes of the main working pump 410, so that the main working pump 410 meets the power requirements of the working system 400.

[0117] During pure electric operation while parked, the control system 100 continuously acquires the power demand of the main working pump 410, the vehicle's auxiliary power, the actual torque of the ISG motor 310, the state of charge of the power battery 320, the temperature of the power battery 320, the health status of the power battery 320, the allowable discharge power of the power battery 320, and the voltage of the high-voltage DC bus 321.

[0118] Engine intervention conditions may include at least one of the following conditions: The sum of the power demand of the main working pump 410 and the auxiliary power of the vehicle is always greater than the allowable discharge power of the power battery 320. The actual electric torque of the ISG motor 310 reaches or is close to the preset electric torque limit. The state of charge (SOC) of the power battery 320 is lower than the preset SOC. The temperature of the 320 power battery exceeds the suitable temperature range for high-power discharge. The 320 health status of the power battery resulted in the allowable discharge power being lower than the preset power. The voltage of the high-voltage DC bus 321 is lower than the preset voltage, or the rate of voltage drop of the bus exceeds the preset threshold. The duration of the power shortage predicted by the operating instructions of the working device exceeds the preset time.

[0119] like Figure 5 As shown, during the initial stage of engine 210 engagement, the engine decoupling clutch 230 remains disengaged, ensuring that the engine 210 starting process is mechanically decoupled from the ISG working shaft 311, thereby reducing the direct impact of the engine starting process on the input power of the main working pump 410.

[0120] After the engine 210 is started by the engine starting device 212 and enters the preset operating state, the control system 100 causes the first reversible hydraulic press 240 to gradually increase its displacement from a zero displacement state.

[0121] At this time, the engine 210 drives the first reversible hydraulic press 240 to work in pump mode, establishes hydraulic flow and working pressure difference in the closed hydraulic circuit 260, and drives the second reversible hydraulic press 250 to work in motor mode, so that part of the power of the engine 210 is transmitted to the ISG working shaft 311 through the hydraulic coupling channel.

[0122] As the hydraulic transmission torque gradually increases, the control system 100 adjusts the output torque of the ISG motor 310 accordingly, so that the hydraulic transmission torque and the output torque of the ISG motor 310 together meet the torque requirements of the main working pump 410.

[0123] When the working pressure difference of the closed hydraulic circuit 260, the actual displacement of the first reversible hydraulic press 240, and the operating status of the second reversible hydraulic press 250 reach the preset range, the control system 100 determines that the hydraulic pre-transmission power has been established.

[0124] Before the hydraulic pre-transmission power is established, the engine decoupling clutch 230 remains disengaged to avoid direct mechanical engagement of the engine 210 before it has established stable auxiliary power.

[0125] like Figure 6-7 As shown, after the hydraulic pre-transmission power is established, the control system 100 obtains the speed status of both sides of the engine decoupling clutch 230 according to the first speed detection device 610 and the second speed detection device 620.

[0126] When there are other transmission components between the engine output shaft 211 and the ISG working shaft 311, the control system 100 converts the detected speed into the corresponding speed on both sides of the engine decoupling clutch 230 according to the corresponding transmission ratio, and calculates the speed difference between the two.

[0127] The control system 100 gradually reduces the speed difference between the two sides of the engine decoupling clutch 230 by adjusting at least one of the engine speed 210, the displacement of the first reversible hydraulic press 240, and the output torque of the ISG motor 310.

[0128] When the speed difference enters the preset engagement range, the control system 100 gradually increases the engagement pressure of the engine decoupling clutch 230 through the first proportional control valve 520.

[0129] As the engagement pressure of the engine decoupling clutch 230 increases, its mechanically transmitted torque gradually increases. At the same time, the control system 100 gradually reduces the displacement of the first reversible hydraulic press 240 through the second proportional control valve 530, thereby gradually reducing the hydraulically transmitted torque in the hydraulic coupling channel.

[0130] Therefore, the power of engine 210 is gradually transferred from the hydraulic coupling channel to the mechanical coupling channel, rather than suddenly switching from one power path to another at a certain moment.

[0131] During the aforementioned power transfer process, the control system 100 continuously determines the required torque of the main working pump 410, the mechanical transmission torque, and the hydraulic transmission torque, and adjusts the ISG motor 310 according to the deviation between the three.

[0132] When the sum of the mechanically transmitted torque and the hydraulically transmitted torque is less than the torque required by the main working pump 410, the ISG motor 310 increases the electric torque; when the sum of the two is greater than the torque required by the main working pump 410, the ISG motor 310 decreases the electric torque and enters the power generation state when the corresponding conditions are met.

[0133] The rapid torque regulation of the ISG motor 310 compensates for the torque deviation caused by the difference in dynamic response between the engine decoupling clutch 230 and the hydraulic coupling channel, thereby keeping the input torque of the main working pump 410 within a preset fluctuation range.

[0134] like Figure 8 As shown, when the engine decoupling clutch 230 reaches a fully engaged state and the speed difference between the two sides remains within the allowable range for a preset time, the control system 100 determines that the mechanical coupling channel is stably established.

[0135] Subsequently, the control system 100 causes the first reversible hydraulic press 240 to gradually return to the zero displacement state, and the second reversible hydraulic press 250 switches to the preset zero displacement state, so that the hydraulic coupling channel stops effective power transmission, and the engine 210 drives the main working pump 410 mainly through the mechanical coupling channel, AMT gearbox 280 and power distribution unit.

[0136] After the engine 210 stably drives the main working pump 410, the control system 100 determines the working state of the ISG motor 310 based on the actual output power of the engine 210 and the power required by the main working pump 410.

[0137] When the available output power of the engine 210 is insufficient to independently meet the needs of the working system 400, the ISG motor 310 is controlled to operate in electric mode, and together with the engine 210, it provides power to the main working pump 410.

[0138] When the engine 210 has surplus power and the power battery 320 is allowed to be charged, the ISG motor 310 is controlled to work in the power generation state, converting part of the surplus mechanical power of the engine 210 into electrical energy, and charging the power battery 320 through the high-voltage DC bus 321.

[0139] Therefore, the ISG motor 310 can undertake pure electric drive, power switching compensation, engine assist and power generation functions according to the power requirements of the whole vehicle.

[0140] like Figure 9As shown, when the power demand of the working system 400 decreases and the allowable output capacity of the power battery 320 and the ISG motor 310 can meet the requirements of pure electric operation for parking, the control system 100 can control the engine 210 to disengage.

[0141] When the engine 210 is disengaged, the control system 100 first enables the ISG motor 310 to establish the corresponding electric compensation torque.

[0142] While the engine decoupling clutch 230 remains engaged, the first reversible hydraulic press 240 gradually increases its displacement from zero displacement, and the second reversible hydraulic press 250 switches to the preset working displacement state, so that the hydraulic coupling channel can re-establish hydraulic transmission capability.

[0143] When the hydraulically transmitted torque reaches the preset range, the control system 100 gradually reduces the engagement pressure of the engine decoupling clutch 230 through the first proportional control valve 520, thereby gradually reducing the mechanically transmitted torque.

[0144] During this process, the output torque of the ISG motor 310 is adjusted according to the changes in mechanically transmitted torque and hydraulically transmitted torque to compensate for the changes in the input torque of the main working pump 410.

[0145] After the engine decoupling clutch 230 is completely disengaged, the mechanical power transmission between the engine 210 and the ISG working shaft 311 is cut off, and the ISG motor 310 takes over the driving needs of the main working pump 410.

[0146] Subsequently, the first reversible hydraulic press 240 is controlled to return to the zero displacement state and the second reversible hydraulic press 250 is switched to the preset zero displacement state, so that the hydraulic coupling channel stops effective power transmission and the engine 210 is controlled to stop, so that the vehicle returns to the parking pure electric operation state.

[0147] Through the above control, the mechanical power during the engine withdrawal process can also be continuously transferred to the hydraulic power and ISG motor power first, avoiding the sudden disappearance of mechanically transmitted torque and causing power fluctuations in the working system.

[0148] like Figure 10 As shown, when the vehicle is in motion, the power take-off engagement mechanism remains disengaged, the driving clutch 281 is engaged, and the power output from at least one of the engine 210 and the ISG motor 310 is transmitted to the drive axle 220 in sequence through the AMT gearbox 280, the power take-off 270 and the driving clutch 281.

[0149] Depending on the vehicle's power requirements and the status of the 320 power battery, the vehicle can be driven by an engine, an ISG motor, or a combination of both.

[0150] When the output power of the engine 210 exceeds the current driving requirements of the vehicle and the power battery 320 is allowed to be charged, the ISG motor 310 can also enter the power generation state to recover the excess power of the engine 210.

[0151] The control system 100 monitors the engine decoupling clutch 230, the closed hydraulic circuit 260, the first reversible hydraulic press 240, the working power take-off engagement mechanism, and the vehicle parking status.

[0152] When the pressure of the closed hydraulic circuit 260 is abnormal or the displacement adjustment of the first reversible hydraulic press 240 is abnormal, the control system 100 stops the hydraulic coupling channel from continuing to build power and returns the first reversible hydraulic press 240 to the zero displacement state.

[0153] When the engine decoupling clutch 230 experiences an engagement abnormality, the control system 100 stops the current mechanical engagement process and, depending on the actual situation, keeps the engine decoupling clutch 230 in a disengaged state or returns it to a disengaged state.

[0154] When the power take-off engagement mechanism fails to reach the preset engagement state, the driving clutch 281 is not fully disengaged, the vehicle speed is not zero, or the parking brake is not in an effective state, the control system 100 prohibits the main working pump 410 from entering the high-power working state.

[0155] When the engine 210 or the power coupling unit fails, but the power battery 320 and the ISG motor 310 can still work normally, the control system 100 enters the pure electric degraded operation state, and the ISG motor 310 drives the main working pump 410 within the allowable discharge power range of the power battery 320.

[0156] In pure electric degraded operation mode, the allowable output power of the main working pump 410 can be reduced, the operating speed of the working device can be limited, or the working device can be prohibited from continuing to perform actions that increase potential energy, while allowing descent, recovery, reset and other actions that help reduce operational risks.

[0157] Example 2 like Figure 11-12 As shown, the overall structure and control principle of this embodiment are basically the same as those of Embodiment 1. The main difference is that the first reversible hydraulic press 240 and the second reversible hydraulic press 250 are both hydraulic presses with adjustable displacement. The control system adjusts the displacement of the first reversible hydraulic press 240 and the second reversible hydraulic press 250 respectively to change the equivalent hydraulic transmission ratio, hydraulic transmission torque and speed adjustment range of the hydraulic coupling channel.

[0158] Specifically, the first reversible hydraulic press 240 is provided with a first displacement actuator 241, which is used to change the position of the swashplate tilt angle, swing angle or other displacement adjustment mechanism of the first reversible hydraulic press 240; the second reversible hydraulic press 250 is further provided with a second displacement actuator 251, which is used to change the position of the swashplate tilt angle, swing angle or other displacement adjustment mechanism of the second reversible hydraulic press 250.

[0159] Based on the independent electro-hydraulic control valve assembly described in Embodiment 1, this embodiment further includes a third proportional control valve 540. A pilot pressure source is connected to the first displacement actuator 241 via the second proportional control valve 530 to adjust the displacement of the first reversible hydraulic press 240; the pilot pressure source is connected to the second displacement actuator 251 via the third proportional control valve 540 to adjust the displacement of the second reversible hydraulic press 250. The second proportional control valve 530 and the third proportional control valve 540 respectively receive control signals output from the control system, enabling the displacements of the first reversible hydraulic press 240 and the second reversible hydraulic press 250 to be independently and continuously adjusted.

[0160] This embodiment also includes a second displacement detection device (not shown in the figure) corresponding to the second reversible hydraulic press 250. The displacement detection device 640 in Embodiment 1 serves as the first displacement detection device, used to detect the actual displacement of the first reversible hydraulic press 240 or the position of the first displacement actuator 241; the second displacement detection device is used to detect the actual displacement of the second reversible hydraulic press 250 or the position of the second displacement actuator 251. The control system implements closed-loop displacement control for the first reversible hydraulic press 240 and the second reversible hydraulic press 250 based on the detection results of the first displacement detection device 640 and the second displacement detection device, respectively.

[0161] The first displacement detection device 640 and the second displacement detection device can use position sensors for directly detecting the swashplate angle, swing angle or variable mechanism position of the hydraulic press, or determine the actual displacement of the corresponding hydraulic press based on the control pressure of the hydraulic press, the actuator displacement and the pre-calibrated correspondence.

[0162] Ignoring hydraulic leakage, the hydraulic flow rate generated by the first reversible hydraulic press 240 is related to its displacement and rotational speed, while the rotational speed of the second reversible hydraulic press 250 is related to the hydraulic flow rate and displacement entering the second reversible hydraulic press 250. Therefore, by changing the displacement ratio of the first reversible hydraulic press 240 and the second reversible hydraulic press 250, the equivalent hydraulic transmission ratio between the engine side and the ISG working shaft side can be changed. When a fixed mechanical transmission mechanism is also provided between the first reversible hydraulic press 240 and the second reversible hydraulic press 250 and their corresponding shafts, the control system calculates the hydraulic transmission relationship in conjunction with the fixed mechanical transmission ratio.

[0163] During the hydraulic pre-transmission power stage after engine intervention, the control system determines the target hydraulic transmission torque of the hydraulic coupling channel based on the required torque of the main working pump and the working pressure difference of the closed hydraulic circuit, and coordinates the determination of the target displacement of the first reversible hydraulic press 240 and the second reversible hydraulic press 250. When it is necessary to increase the hydraulic transmission torque, the displacement of the second reversible hydraulic press 250 can be increased, and the displacement of the first reversible hydraulic press 240 can be adjusted accordingly to provide the required hydraulic flow.

[0164] During the speed synchronization phase on both sides of the engine decoupling clutch, the control system determines the target displacement ratio of the first reversible hydraulic press 240 and the second reversible hydraulic press 250 based on the engine side speed, ISG working shaft speed and target synchronization speed relationship, and adjusts the first displacement actuator 241 and the second displacement actuator 251 through the second proportional control valve 530 and the third proportional control valve 540 respectively to change the equivalent hydraulic transmission ratio of the hydraulic coupling channel.

[0165] For example, when the engine speed remains essentially constant, if it is necessary to increase the output speed of the second reversible hydraulic press 250, the displacement of the first reversible hydraulic press 240 can be increased and / or the displacement of the second reversible hydraulic press 250 can be decreased; if it is necessary to increase the output torque of the second reversible hydraulic press 250 under the same working pressure difference, the displacement of the second reversible hydraulic press 250 can be increased. This allows for the coordinated adjustment of the speed and torque characteristics of the hydraulic coupling channel using the displacements of the two variable hydraulic presses.

[0166] During the takeover of the mechanical coupling channel, the control system gradually increases the engagement pressure of the engine decoupling clutch and gradually reduces the effective displacement of at least one of the first reversible hydraulic press 240 and the second reversible hydraulic press 250 according to the increase in mechanical transmission torque, thereby gradually reducing the hydraulic transmission torque. During this process, the control system continues to determine the target torque of the ISG motor based on the main working pump's required torque, the mechanical transmission torque, and the hydraulic transmission torque to compensate for torque deviations generated during power transfer.

[0167] Once the engine decoupling clutch is fully engaged and power is transmitted stably, the control system returns at least one of the first reversible hydraulic press 240 and the second reversible hydraulic press 250 to a zero displacement or preset minimum effective displacement state, thereby stopping or substantially stopping the effective power transmission of the hydraulic coupling channel.

[0168] Furthermore, both the first displacement actuator 241 and the second displacement actuator 251 can be equipped with a failure reset mechanism. When the corresponding proportional control valve loses power, the pilot pressure is abnormal, or the deviation between the actual displacement and the target displacement exceeds the preset range, the corresponding variable displacement hydraulic press returns to the zero displacement or preset safe displacement state. The control system also limits the displacement adjustment range of both based on the working pressure difference of the closed hydraulic circuit, the rotational speed of the first reversible hydraulic press 240 and the second reversible hydraulic press 250, and the actual displacement, to prevent the hydraulic press from overspeeding, the closed hydraulic circuit from being overpressurized, or the hydraulic press from entering an unpermitted working area.

[0169] Therefore, in this embodiment, the first displacement actuator 241, the second proportional control valve 530 and the first displacement detection device 640 form a displacement closed-loop control branch for the first reversible hydraulic press 240, and the second displacement actuator 251, the third proportional control valve 540 and the second displacement detection device form a displacement closed-loop control branch for the second reversible hydraulic press 250. This enables the control system to independently and coordinately adjust the displacement of the two reversible hydraulic presses, thereby achieving active adjustment of the equivalent hydraulic transmission ratio, output torque and speed of the hydraulic coupling channel.

[0170] Example 3 This embodiment provides a power control method for a hybrid power vehicle, applied to the power control system described in Embodiment 1 or Embodiment 2, and includes the following steps.

[0171] After the vehicle enters the parking operation state, the control system acquires the vehicle speed, parking brake status, drive clutch status, and power take-off engagement mechanism status. When the vehicle speed is zero, the parking brake is effective, and the drive clutch is disengaged, the control system engages the power take-off mechanism, establishing a power transmission path between the power take-off unit and the main work pump.

[0172] In pure electric operation mode while parked, the control system disengages the engine decoupling clutch and controls the first reversible hydraulic press to zero displacement, thus stopping effective power transmission through the hydraulic coupling channel. The power battery supplies power to the ISG motor, which drives the main working pump via the power distribution unit. The control system adjusts the speed and output torque of the ISG motor according to the working pressure, displacement, and operational requirements of the main working pump.

[0173] During pure electric operation while parked, the control system continuously acquires the power demand of the main working pump, the actual torque of the ISG motor, the state of charge of the power battery, and the allowable discharge power of the power battery. When the power demand of the main working pump exceeds the pure electric drive capability, the ISG motor reaches the preset torque limit, the state of charge of the power battery is lower than the preset value, or the allowable discharge power of the power battery is insufficient, the engine intervention conditions are determined to be met.

[0174] Once the engine intervention conditions are met, the control system keeps the engine decoupling clutch disengaged and starts the engine. After the engine enters a stable operating state, the control system gradually increases the displacement of the first reversible hydraulic press from zero, causing the engine to drive the first reversible hydraulic press to operate in pump mode, and causing the second reversible hydraulic press to switch to the preset working displacement state. The hydraulic oil drives the second reversible hydraulic press to operate in motor mode through a closed hydraulic circuit, thereby outputting hydraulic torque to the ISG working shaft.

[0175] During the gradual establishment of power in the hydraulic coupling channel, the control system adjusts the output torque of the ISG motor accordingly, so that the hydraulic transmission torque and the ISG motor output torque together meet the torque requirements of the main working pump. When the working pressure difference of the closed hydraulic circuit, the actual displacement of the first reversible hydraulic press, and the output state of the second reversible hydraulic press reach the preset range, it is determined that the hydraulic pre-transmission power has been established.

[0176] Subsequently, the control system acquires the rotational speeds on both sides of the engine decoupling clutch, and gradually reduces the speed difference between the two sides of the clutch by adjusting at least one of the engine speed, the displacement of the first reversible hydraulic press, and the output torque of the ISG motor.

[0177] When the speed difference between the two sides of the engine decoupling clutch enters the preset engagement range, the control system gradually increases the engagement pressure of the engine decoupling clutch, so that the mechanical transmission torque of the mechanical coupling channel gradually increases; at the same time, it gradually reduces the displacement of the first reversible hydraulic press, so that the hydraulic transmission torque of the hydraulic coupling channel gradually decreases.

[0178] During power transfer, the control system determines the target torque of the ISG motor based on the required torque of the main working pump, the mechanical transmission torque, and the hydraulic transmission torque. When the sum of the mechanical transmission torque and the hydraulic transmission torque is less than the required torque of the main working pump, the control system increases the electric compensation torque of the ISG motor; when the sum of the two is greater than the required torque of the main working pump, the control system reduces the electric torque of the ISG motor or controls the ISG motor to enter generator mode to maintain continuous power input to the main working pump.

[0179] When the engine decoupling clutch reaches full engagement and the speed difference between its two sides remains within the allowable range for a preset time, the mechanical coupling channel is determined to be stably established. The control system then gradually returns the first reversible hydraulic press to a zero-displacement state and switches the second reversible hydraulic press to a zero-displacement state, with the main working pump driven primarily by the engine through the mechanical coupling channel and the power distribution unit.

[0180] When the engine is operating under stable drive conditions, if the engine output power is insufficient, the ISG motor is controlled to enter electric assist mode; when the engine has surplus power, the ISG motor is controlled to enter generator mode and the generated electrical energy is stored in the power battery.

[0181] When the power demand of the main working pump decreases and the allowable discharge power of the power battery can meet the pure electric operation requirements of the vehicle, the control system executes the engine disengagement process. First, it controls the ISG motor to establish electric compensation torque and gradually increases the displacement of the first reversible hydraulic press, while coordinating to switch the displacement state of the second reversible hydraulic press to re-establish hydraulic transmission torque; then, it gradually reduces the engagement pressure of the engine decoupling clutch, so that the mechanical transmission torque gradually decreases.

[0182] After the engine decoupling clutch is fully disengaged, the main working pump is driven by the ISG motor. The control system then returns the first reversible hydraulic press to zero displacement and switches the second reversible hydraulic press to zero displacement, while controlling the engine to stop, thus restoring the vehicle to a parking, purely electric operating state.

[0183] During the aforementioned control process, when abnormal pressure in the closed-loop hydraulic circuit, abnormal hydraulic press displacement adjustment, abnormal engagement of the engine decoupling clutch, or abnormal status of the power take-off engagement mechanism is detected, the control system stops the current power switching process, keeps the engine decoupling clutch in or returns to the disengaged state, and returns the first reversible hydraulic press to the zero displacement state. Provided the power battery and ISG motor are functioning normally, the ISG motor drives the main working pump with limited power to ensure the safe shutdown or reset of the working system.

[0184] In the above implementation, "gradually increasing" or "gradually decreasing" can refer to continuous changes over time or stepwise changes according to multiple control stages; "transmitting power" includes transmitted torque and transmitted power; "continuous input power" means that during the power source switching process, the actual input torque or input power of the main working pump remains within a preset range that meets the normal operation of the working system, without requiring it to remain at the same value at any given time.

Claims

1. A power control system for a hybrid power vehicle, characterized in that, It includes a control system (100), a main drive system (200), a power assistance system (300), and a working system (400); The overall drive system (200) includes a main power unit, a power coupling unit, a power distribution unit and a drive unit. The main power unit includes an engine (210) and the drive unit includes a drive axle (220). The power assistance system (300) includes an auxiliary power unit and an energy storage unit. The auxiliary power unit includes an ISG motor (310), and the energy storage unit includes a power battery (320) electrically connected to the ISG motor (310). The working system (400) includes a main working pump (410) for receiving power from at least one of the main drive system (200) and the power assistance system (300); The power coupling unit is located between the main power unit and the auxiliary power unit, and includes a parallel mechanical coupling channel and a hydraulic coupling channel; The mechanical coupling channel includes an engine decoupling clutch (230) for selectively engaging or disengaging the mechanical power transmission between the engine (210) and the ISG motor (310); The hydraulic coupling channel includes a first reversible hydraulic press (240), a second reversible hydraulic press (250), and a closed hydraulic circuit (260) connecting the first reversible hydraulic press (240) and the second reversible hydraulic press (250). The first reversible hydraulic press (240) is driven to the engine (210), and the second reversible hydraulic press (250) is driven to the ISG motor (310). It is used to realize the power transmission between the engine (210) and the ISG motor (310) when the engine decoupling clutch (230) is disengaged. The power distribution unit includes a power take-off (270) and a working power take-off engagement mechanism. The power take-off (270) is connected to the auxiliary power unit, the drive unit, and the working system (400) respectively, and is used to distribute the power output by at least one of the main power unit and the power auxiliary system (300) to the drive unit and the working system (400). The working power take-off engagement mechanism is used to selectively connect or disconnect the power transmission between the power take-off (270) and the main working pump (410). The control system (100) is connected to the engine (210), ISG motor (310), engine decoupling clutch (230), hydraulic coupling channel, and working power take-off engagement mechanism, and is configured as follows: In the pure electric operation state of the vehicle, the engine decoupling clutch (230) is disengaged, the hydraulic coupling channel stops transmitting power and the operation power take-off engagement mechanism is engaged, so that the ISG motor (310) drives the main operation pump (410) through the power distribution unit. When the conditions for engine (210) intervention are met, the engine (210) is started while the engine decoupling clutch (230) remains disengaged, and the transmission power of the hydraulic coupling channel is gradually increased so that the power output by the engine (210) is transmitted to the power assistance system (300) and the working system (400) through the hydraulic coupling channel. After the speed difference on both sides of the engine decoupling clutch (230) meets the engagement condition, the transmission torque of the mechanical coupling channel is gradually increased and the transmission power of the hydraulic coupling channel is gradually decreased. At the same time, the output torque of the ISG motor (310) is adjusted to compensate for the input torque deviation of the main working pump (410), thereby realizing the power transfer between the mechanical coupling channel and the hydraulic coupling channel and maintaining the continuous input power of the working system (400).

2. The power control system for a hybrid power vehicle according to claim 1, characterized in that: The engine (210) has an engine output shaft (211), the ISG motor (310) is mounted on the ISG working shaft (311), and the engine decoupling clutch (230) is mounted between the engine output shaft (211) and the ISG working shaft (311). The first reversible hydraulic press (240) is driven to the engine output shaft (211) located on the engine (210) side of the engine decoupling clutch (230), and the second reversible hydraulic press (250) is driven to the ISG working shaft (311) located on the other side of the engine decoupling clutch (230), so that the hydraulic coupling channel crosses the engine decoupling clutch (230) and is connected in parallel with the mechanical coupling channel; The overall drive system (200) also includes an AMT transmission (280), a driving clutch (281), and a reduction gear (290); The AMT gearbox (280) is located between the ISG working shaft (311) and the input end of the power take-off (270), the driving clutch (281) is located between the driving output end of the power take-off (270) and the drive axle (220), and the reduction mechanism (290) is located between the working power take-off end of the power take-off (270) and the main working pump (410). When the vehicle is in motion, the driving clutch (281) engages and the working power take-off engagement mechanism disengages, so that the power output by at least one of the main power unit and the power assistance system (300) is transmitted to the drive axle (220) in sequence through the AMT transmission (280), the power take-off (270) and the driving clutch (281). In the parking operation state, the driving clutch (281) is disengaged and the operation power take-off engagement mechanism is engaged, so that the power output by at least one of the main power unit and the power assistance system (300) is transmitted sequentially to the main operation pump (410) through the AMT gearbox (280), the power take-off (270) and the reduction mechanism (290).

3. The power control system for a hybrid power vehicle according to claim 2, characterized in that: The first reversible hydraulic press (240) has a first working port and a second working port, and the second reversible hydraulic press (250) has a third working port and a fourth working port; The first working port is connected to the third working port through the first working pipeline (261), and the second working port is connected to the fourth working port through the second working pipeline (262), so that the first reversible hydraulic press (240) and the second reversible hydraulic press (250) form a closed hydraulic circuit (260); The closed hydraulic circuit (260) also includes a replenishing pump (263), a replenishing check valve (264), and a pressure limiting assembly (265); The output end of the replenishing pump (263) is connected to the first working pipeline (261) and the second working pipeline (262) through two replenishing check valves (264) respectively, and is used to replenish hydraulic oil to the low-pressure working pipelines in the first working pipeline (261) and the second working pipeline (262); The pressure limiting component (265) is connected between the first working pipeline (261) and the second working pipeline (262) to limit the working pressure difference between the first working pipeline (261) and the second working pipeline (262); The first working pipeline (261) and the second working pipeline (262) are respectively equipped with pressure detection devices; Both the first reversible hydraulic press (240) and the second reversible hydraulic press (250) are hydraulic presses with adjustable displacement. The control system (100) adjusts the displacement of the first reversible hydraulic press (240), changes the flow rate of the closed hydraulic circuit (260), and the torque output by the second reversible hydraulic press (250) to the ISG working shaft (311) to adjust the transmission power of the hydraulic coupling channel.

4. The power control system for a hybrid power vehicle according to claim 1, characterized in that: The hydraulic coupling channel also includes a first displacement actuator (241) for adjusting the displacement of the first reversible hydraulic press (240); The power control system also includes an independent electro-hydraulic control valve assembly (500), which includes a pilot pressure source (510), a first proportional control valve (520), and a second proportional control valve (530). The pilot pressure source (510) is connected to the hydraulic actuator (231) of the engine decoupling clutch (230) via a first proportional control valve (520) to form a first control branch for independently adjusting the engagement pressure of the engine decoupling clutch (230). The pilot pressure source (510) is connected to the first displacement actuator (241) of the first reversible hydraulic press (240) through the second proportional control valve (530) to form a second control branch for independently adjusting the displacement of the first reversible hydraulic press (240); The first proportional control valve (520) and the second proportional control valve (530) are electrically connected to the control system (100) respectively, so that the engagement pressure of the engine decoupling clutch (230) and the displacement of the first reversible hydraulic press (240) can be adjusted independently. The first proportional control valve (520) is a proportional pressure reducing relief valve, and the second proportional control valve (530) is a proportional directional valve or a proportional pressure valve. The engine decoupling clutch (230) is configured to disengage when the first proportional control valve (520) is de-energized or when the pressure of the pilot pressure source (510) is lower than a preset pressure, and the first reversible hydraulic press (240) is configured to reset to a zero displacement state when the second proportional control valve (530) is de-energized.

5. The power control system for a hybrid power vehicle according to claim 2, characterized in that: The power control system also includes: A first speed detection device (610) for detecting the speed of the engine output shaft (211); A second speed detection device (620) for detecting the speed of the ISG working shaft (311); Engagement pressure detection device (630) for detecting engagement pressure of the engine decoupling clutch (230); Displacement detection device (640) for detecting the displacement of the first reversible hydraulic press (240); A circuit pressure detection device (650) for detecting the working pressure difference of the closed hydraulic circuit (260); and A load detection device (660) for detecting the working pressure and displacement of the main working pump (410); The control system (100) is also configured to: The required torque of the working system (400) is determined based on the working pressure and displacement of the main working pump (410); The hydraulic transmission torque of the hydraulic coupling channel is determined based on the working pressure difference of the closed hydraulic circuit (260) and the displacement of the second reversible hydraulic press (250). The mechanical transmission torque of the mechanical coupling channel is determined based on the engagement pressure of the engine decoupling clutch (230), the speed difference on both sides of the engine decoupling clutch (230), and the engagement state. The target torque of the ISG motor (310) is determined based on the deviation between the required torque of the working system (400) and the sum of the mechanically transmitted torque and the hydraulically transmitted torque; During the process of the mechanical transmission torque gradually increasing and the hydraulic transmission torque gradually decreasing, the target torque of the ISG motor (310) is adjusted so that the input torque of the main working pump (410) is kept within a preset fluctuation range. After the engine decoupling clutch (230) is fully engaged, the first reversible hydraulic press (240) is controlled to return to the zero displacement state, so that the engine (210) drives the main working pump (410) through the mechanical coupling channel, and the ISG motor (310) is controlled to enter the power generation state according to the surplus power of the engine (210).

6. A power control method for a hybrid power vehicle, characterized in that: The hybrid power vehicle includes an engine (210), an ISG motor (310), a power coupling unit, a power distribution unit, a power battery (320), and a main working pump (410). The engine (210) and the ISG motor (310) transmit power through the power coupling unit, which includes a mechanical coupling channel and a hydraulic coupling channel arranged in parallel. The mechanical coupling channel includes an engine decoupling clutch (230) disposed between the engine (210) and the ISG motor (310); The hydraulic coupling channel includes a first reversible hydraulic press (240), a second reversible hydraulic press (250), and a closed hydraulic circuit (260) connecting the first reversible hydraulic press (240) and the second reversible hydraulic press (250). The first reversible hydraulic press (240) is driven to the engine output shaft (211) of the engine (210), and the second reversible hydraulic press (250) is driven to the ISG working shaft (311) where the ISG motor (310) is located. The power distribution unit is used to transmit the power output by at least one of the engine (210) and the ISG motor (310) to the main working pump (410), and the power battery (320) is electrically connected to the ISG motor (310) through the high voltage DC bus (321); The power control method includes: S100. In the pure electric operation state of parking, the engine decoupling clutch (230) is controlled to disengage, and the hydraulic coupling channel is stopped from transmitting power. The power battery (320) supplies power to the ISG motor (310), so that the ISG motor (310) drives the main working pump (410) through the power distribution unit. S200. When the engine intervention conditions are met, keep the engine decoupling clutch (230) disengaged and start the engine (210). Adjust the displacement of the first reversible hydraulic press (240) so that the power output by the engine (210) is transmitted to the ISG working shaft (311) in sequence through the first reversible hydraulic press (240), the closed hydraulic circuit (260) and the second reversible hydraulic press (250) to establish the hydraulic transmission power of the hydraulic coupling channel. S300. When the speed difference between the two sides of the engine decoupling clutch (230) meets the engagement condition, the mechanical transmission torque of the engine decoupling clutch (230) is gradually increased, and the hydraulic transmission power of the hydraulic coupling channel is gradually reduced, so that the power output by the engine (210) is gradually transferred from the hydraulic coupling channel to the mechanical coupling channel. S400. During the power transfer process, the output torque of the ISG motor (310) is adjusted according to the required torque of the main working pump (410), the mechanical transmission torque of the mechanical coupling channel and the hydraulic transmission torque of the hydraulic coupling channel to compensate for the input torque deviation of the main working pump (410). S500 After the engine decoupling clutch (230) is fully engaged, the hydraulic coupling channel stops transmitting power, and the engine (210) drives the main working pump (410) through the mechanical coupling channel and the power distribution unit.

7. A power control method for a hybrid power vehicle according to claim 6, characterized in that: Engine intervention conditions include at least one of the following: The sum of the power demand of the main working pump (410) and the auxiliary power of the vehicle is consistently greater than the allowable discharge power of the power battery (320); The electric torque of the ISG motor (310) reaches the preset electric torque limit; The state of charge of the power battery (320) is lower than the preset state of charge; The temperature or health condition of the power battery (320) causes the allowable discharge power of the power battery (320) to be lower than the preset power; The voltage drop rate of the high-voltage DC bus (321) exceeds a preset threshold. The predicted duration of the parking operation power gap exceeds the preset time; When the conditions for engine (210) intervention are met, the engine decoupling clutch (230) is kept disengaged, and the engine (210) is started by an engine starting device (212) independent of the ISG motor (310), so that the torque and speed fluctuations generated during the engine (210) start-up process are not transmitted to the ISG working shaft (311) and the main working pump (410) through the mechanical coupling channel.

8. A power control method for a hybrid power vehicle according to claim 6, characterized in that: Before the engine decoupling clutch (230) begins to engage, the rotational speed of the engine output shaft (211) and the rotational speed of the ISG working shaft (311) are obtained, and the speed difference between the two sides of the engine decoupling clutch (230) is determined. By adjusting at least one of the target speed of the engine (210), the displacement of the first reversible hydraulic press (240), and the output torque of the ISG motor (310), the speed difference is reduced to a preset engagement range; After the speed difference enters the preset engagement range: The engagement pressure of the engine decoupling clutch (230) is increased by the first proportional control valve (520) according to the first preset change rate, so as to gradually increase the mechanical transmission torque of the mechanical coupling channel. The displacement of the first reversible hydraulic press (240) is reduced by the second proportional control valve (530) according to the second preset rate of change, so as to gradually reduce the hydraulic transmission torque of the hydraulic coupling channel. The output torque of the ISG motor (310) is adjusted in real time based on the working pressure difference of the closed hydraulic circuit (260), the engagement pressure of the engine decoupling clutch (230), and the required torque of the main working pump (410). The mechanically transmitted torque, the hydraulically transmitted torque, and the output torque of the ISG motor (310) are combined to meet the torque requirements of the main working pump (410) and maintain the continuous input torque of the main working pump (410).

9. A power control method for a hybrid power vehicle according to claim 6, characterized in that: When switching from engine (210) driven operation mode to parking pure electric operation mode: Reduce the generating torque of the ISG motor (310) and enable the ISG motor (310) to establish electric compensation torque; With the engine decoupling clutch (230) engaged, the first reversible hydraulic press (240) is controlled to gradually increase the displacement from zero displacement, so that the hydraulic coupling channel can be re-established to transmit hydraulic torque. After the hydraulic transmission torque reaches the preset torque, the engagement pressure of the engine decoupling clutch (230) is gradually reduced by the first proportional control valve (520), so that the mechanical transmission torque of the mechanical coupling channel is gradually reduced. The electric torque of the ISG motor (310) is adjusted according to the changes in mechanical and hydraulic transmission torque to compensate for the input torque deviation of the main working pump (410). After the engine decoupling clutch (230) is fully disengaged, the main working pump (410) is driven by the ISG motor (310) through the power distribution unit; Then, the first reversible hydraulic press (240) is controlled to return to the zero displacement state, so that the hydraulic coupling channel stops transmitting power and the engine (210) is stopped.

10. A power control method for a hybrid power vehicle according to claim 8, characterized in that: When the working pressure difference of the closed hydraulic circuit (260) is abnormal, the deviation between the actual displacement and the target displacement of the first reversible hydraulic press (240) exceeds the preset value, or the output state of the second reversible hydraulic press (250) is abnormal, the first fault state is detected. The engagement process of the engine decoupling clutch (230) is stopped, the engine decoupling clutch (230) is kept disengaged or returned to the disengaged state, and the first reversible hydraulic press (240) is controlled to reset to the zero displacement state. When the engagement pressure of the engine decoupling clutch (230) reaches the preset pressure, and the speed difference between the two sides of the engine decoupling clutch (230) does not decrease to the preset range, it is the second fault state. The engagement pressure of the engine decoupling clutch (230) is stopped, and the input torque of the main working pump (410) is maintained by the ISG motor (310). When the first proportional control valve (520) loses power or the pilot pressure source (510) is under insufficient pressure, it is the third fault state, causing the engine decoupling clutch (230) to disengage; When the second proportional control valve (530) loses power or the displacement control of the first reversible hydraulic press (240) is abnormal, it is the fourth fault state, which resets the first reversible hydraulic press (240) to the zero displacement state and stops the transmission of power through the hydraulic coupling channel. In the aforementioned fault state, the ISG motor (310) drives the main working pump (410) within the allowable discharge power range of the power battery (320), and limits the maximum output power of the main working pump (410) or prohibits the working system (400) from performing actions that increase the potential energy of the vehicle working device.

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