A hybrid power system for a construction machine and a control method thereof

Abstract

The application discloses an engineering machinery hybrid power system and a control method thereof. The system comprises a walking system, a working system, an energy storage auxiliary system and a controller. The energy storage auxiliary system selectively delivers and recovers oil to the walking system or the working system under the control of the controller. The system is provided with a light-load electric drive mode and a heavy-load hybrid drive mode. In the light-load electric drive mode, the system is mainly driven by the motor. When the power of the heavy-load subsystem exceeds the maximum power of the motor, the hydraulic accumulator assists in supplementing. In the energy recovery stage, energy can flow back through the regenerative path. The application solves the problems of large installed power and high cost of the existing electro-hydraulic hybrid drive system, reduces the rated power of the motor, reduces the size and energy consumption of the equipment, improves the energy recovery and utilization efficiency, reduces the waste of invalid energy, and at the same time, through the assistance of the accumulator, the power response of the system in the high-load transient state is enhanced, the operation continuity and operation cycle are improved, and the efficient coordination and distribution of the energy of multiple subsystems are realized.

Description

Technical Field

[0001] This application relates to the field of engineering machinery technology, and in particular to a hybrid power system for engineering machinery and its control method. Background Technology

[0002] In the field of construction machinery, the choice of drive method has a crucial impact on equipment performance, energy consumption, and cost. Currently, existing drive methods for construction machinery mainly fall into three categories: pure electric drive, pure hydraulic drive, and electro-hydraulic hybrid drive. Among them, the electro-hydraulic hybrid drive system has wide applications in construction machinery. It powers the actuators through a motor and pump or high-voltage accumulator, while simultaneously achieving energy recovery in conjunction with the motor. This drive method cleverly integrates the advantages of electric and hydraulic drives, possessing both the precise control and rapid response of electric drives and the high output force and smooth transmission of hydraulic drives. It can reduce energy consumption and improve power performance to a certain extent, playing an important role in many construction machinery such as cranes and loaders.

[0003] However, in actual working conditions, electro-hydraulic hybrid drive systems still face many problems that urgently need to be solved. First, the large installed power and high peak demand are prominent issues. Construction machinery often encounters short-term high-power demand scenarios during operation, such as lifting, rapid acceleration, or sudden heavy loads. To ensure sufficient power performance under these conditions, it is necessary to configure motors with larger rated power, which directly leads to increased equipment size, cost, and energy consumption. Second, energy recovery and utilization are insufficient. A large amount of instantaneous energy during loading, such as energy from hydraulic cylinder lowering and inertial braking, is not fully recovered and is wasted on overflow losses, mechanical braking, and other unfavorable paths. Furthermore, the energy of multiple subsystems is not fully coordinated. Each subsystem operates independently during loading, lacking an effective coordination and allocation mechanism based on a shared energy source. Currently, there is no unified and efficient energy allocation and dynamic coordination solution. Summary of the Invention

[0004] The purpose of this application is to provide a hybrid power system for engineering machinery and its control method, which can improve the above-mentioned problems.

[0005] The embodiments of this application are implemented as follows: In a first aspect, this application provides a hybrid power system for engineering machinery, comprising a walking system, a working system, an energy storage auxiliary system, and a controller; the walking system includes a first motor, a hydraulic motor, and wheels, wherein the first motor and the hydraulic motor drive the wheels to rotate via mechanical components; the working system includes a second motor, a hydraulic pump, and a working hydraulic cylinder, wherein the second motor drives the hydraulic pump to deliver oil to the rodless or rod-side chamber of the working hydraulic cylinder, thereby causing the piston rod of the working hydraulic cylinder to move; both the first motor and the second motor are electrically connected to the controller; the energy storage auxiliary system includes a hydraulic accumulator, which, under the control of the controller, selectively delivers or recovers oil to the walking system or the working system.

[0006] When the hybrid power system of the construction machinery is in light-load electric drive mode, the load is small, the walking system is mainly driven by the first motor, the working system is mainly driven by the second motor to power the hydraulic pump, the hydraulic accumulator is in a holding state, and the controller controls the driving speed and actuator speed by adjusting the speed of the first motor and the second motor.

[0007] When the hybrid power system of construction machinery is in heavy-load hybrid drive mode: the load is large. If the load power of the subsystem exceeds the maximum power of the motor, the controller controls the hydraulic accumulator to selectively supplement the power to the corresponding subsystem, which significantly reduces the demand on the instantaneous power of the motor.

[0008] During the energy recovery phase, such as when the hydraulic cylinder is lowered or the walking system is decelerated and braked, energy flows back to the accumulator or motor / battery through the regeneration path, supporting two paths: the motor generates electricity to charge the battery, and the hydraulic energy directly compresses the accumulator.

[0009] It is understood that the hybrid power system for construction machinery disclosed in this application has the following beneficial effects: First, it addresses the challenges of large installed power and high peak demand by utilizing energy storage devices to compensate for short-term high power demand, thereby reducing the rated power of the motor and decreasing equipment size, cost, and energy consumption; second, it solves the problem of insufficient energy recovery and utilization by recovering instantaneous energy through regeneration paths, reducing waste; and third, it improves the problem of insufficient energy coordination among multiple subsystems by achieving unified and efficient energy allocation and dynamic coordination based on a shared energy source under different high power demands of subsystems.

[0010] In an optional embodiment of this application, the energy storage auxiliary system further includes a first electromagnetic directional valve electrically connected to the controller. The first electromagnetic directional valve includes a first liquid port, a second liquid port, and a third liquid port. The first liquid port is connected to the hydraulic accumulator, the second liquid port is connected to the walking system, and the third liquid port is connected to the working system. When the controller controls the first electromagnetic directional valve to be in a first working state, the first liquid port is connected to the second liquid port. When the controller controls the first electromagnetic directional valve to be in a second working state, the first liquid port is connected to the third liquid port.

[0011] It is understood that when the load power of the walking system is greater than the maximum power of the first motor, the controller controls the first solenoid directional valve to enter the first operating state. When the load power of the working system is greater than the maximum power of the second motor, the controller controls the first solenoid directional valve to enter the second operating state.

[0012] In an optional embodiment of this application, the walking system is further provided with a pressure sensor for monitoring the hydraulic state in the connecting pipe between the hydraulic accumulator and the first liquid port, and a flow sensor for monitoring the oil flow rate in the connecting pipe between the hydraulic accumulator and the first liquid port; the working system is further provided with a displacement sensor for monitoring the displacement state of the piston rod of the working hydraulic cylinder; the pressure sensor, the flow sensor and the displacement sensor are electrically connected to the controller, and the controller controls the first electromagnetic directional valve according to the feedback parameters of the pressure sensor, the flow sensor and the displacement sensor.

[0013] It is understandable that the controller adjusts the working power of the first motor and / or the second motor based on the displacement parameters fed back by the displacement sensor, the hydraulic parameters fed back by the pressure sensor, and the flow parameters fed back by the flow sensor, thereby achieving precise control of the travel speed and the speed of the working hydraulic cylinder.

[0014] In an optional embodiment of this application, the walking system further includes a first gear assembly and a second gear assembly that mesh with each other. The first motor drives the wheel to rotate through the first gear assembly, and the hydraulic motor drives the second gear assembly to rotate, thereby driving the first gear assembly to rotate the wheel through the meshing relationship. The walking system also includes a first oil tank, with the inlet of the hydraulic motor connected to the second oil port and the outlet of the hydraulic motor connected to the first oil tank.

[0015] It is understood that the walking system in this application is a parallel power system, in which the first motor and the hydraulic motor jointly drive the wheels. When encountering scenarios where the load is heavy or the driving speed increases, the hydraulic accumulator supplies oil to the hydraulic motor through the second liquid port, and the first motor and the hydraulic motor simultaneously provide power to the transmission mechanism. Once entering a scenario where the load is light or the driving speed reaches the cruising speed, the engineering machinery equipment only needs to rely on the first motor to maintain the speed.

[0016] In an optional embodiment of this application, the working system further includes a second oil tank and a second electromagnetic directional valve. The second electromagnetic directional valve includes a fourth port, a fifth port, a sixth port, and a seventh port. The fourth port is connected to the outlet of the hydraulic pump and also to the third port. The fifth port is connected to the rod chamber of the working hydraulic cylinder, the sixth port is connected to the rodless chamber of the working hydraulic cylinder, and the seventh port is connected to the inlet of the hydraulic pump. The inlet of the hydraulic pump is also connected to the second oil tank. When the controller controls the second electromagnetic directional valve to be in a third working state, the fourth port is connected to the sixth port, and the fifth port is connected to the seventh port. When the controller controls the second electromagnetic directional valve to be in a fourth working state, the fourth port is connected to the fifth port, and the sixth port is connected to the seventh port.

[0017] It can be understood that when the controller controls the second solenoid directional valve to the third operating state, the hydraulic pump draws oil from the second oil tank and delivers it to the rodless chamber of the working hydraulic cylinder, thereby pushing the piston rod to extend. Excess oil in the rod chamber returns to the second oil tank through the fifth and seventh ports. During this process, if the load power of the working system exceeds the maximum power of the second motor, the hydraulic accumulator delivers oil to the rodless chamber through the third port to increase the working power of the piston rod. When the controller controls the second solenoid directional valve to the fourth operating state, the hydraulic pump draws oil from the second oil tank and delivers it to the rod chamber of the working hydraulic cylinder, thereby compressing the piston rod to retract. Excess oil in the rodless chamber returns to the second oil tank through the sixth and seventh ports. It is evident that the controller can control the reciprocating motion of the piston rod by controlling the second solenoid directional valve.

[0018] In an optional embodiment of this application, a relief valve is further provided between the inlet and outlet of the hydraulic pump. It is understood that when the system pressure exceeds a set value, the relief valve opens, allowing excess oil to flow back to the second oil tank, preventing excessive system pressure from damaging components, and thus protecting the system, maintaining pressure stability, and ensuring safe and reliable operation.

[0019] In an optional embodiment of this application, a first check valve is provided on the oil pipe connecting the outlet of the hydraulic pump and the fourth outlet to prevent oil from flowing into the hydraulic pump.

[0020] In an optional embodiment of this application, a second check valve is provided on the oil pipe connecting the inlet of the hydraulic pump and the seventh port to prevent oil from flowing to the seventh port.

[0021] In an optional embodiment of this application, the rod chamber of the working hydraulic pump is also connected to the second oil tank, and a third check valve is provided on the oil pipe connecting the rod chamber and the second oil tank to prevent oil from flowing into the second oil tank.

[0022] It is understandable that when the controller puts the second solenoid directional valve in the third working state, if the currently operating hydraulic cylinder is lowered, the energy recovery stage begins. The oil in the rodless chamber returns to the hydraulic accumulator through the sixth and fourth ports. At this time, the second oil tank replenishes oil to the rod chamber through the seventh and fifth ports. Additionally, when the operating system is decelerating or lowering the load, if the pressure inside the hydraulic accumulator exceeds a preset pressure threshold, the controller first puts the first solenoid directional valve into the first working state to release oil to the traveling system, and then controls the first solenoid directional valve into the second working state, allowing the hydraulic accumulator to receive the oil returned by the operating system, thus achieving energy recovery.

[0023] Secondly, this application discloses a control method for a hybrid power system of engineering machinery, applicable to any of the hybrid power systems of engineering machinery described in the first aspect, such as... Figure 2 As shown, the method includes the following steps S1 to S3. Here, S1, S2, etc., are merely step identifiers; the execution order of the method does not necessarily follow an ascending numerical order. For example, step S2 may be executed first, followed by step S1. This application does not impose any restrictions.

[0024] S1, control the operating power of the first motor and / or the second motor to drive the walking system or the working system to operate.

[0025] S2, when the load power of the walking system is greater than the maximum power of the first motor, control the hydraulic accumulator to deliver oil to the walking system to assist the walking system in increasing its power.

[0026] S3, when the load power of the working system is greater than the maximum power of the second motor, control the hydraulic accumulator to supply oil to the working system to assist the working system in increasing its power.

[0027] S4, when the walking system is in a deceleration or braking state, control the hydraulic accumulator to connect with the walking system, receive the oil returned by the walking system, and realize energy recovery.

[0028] S5, when the working system is in a deceleration or load-lowering state, control the hydraulic accumulator to connect with the working system, receive the oil returned by the working system, and realize energy recovery.

[0029] In an optional embodiment of this application, the energy storage auxiliary system further includes a first electromagnetic directional valve electrically connected to the controller. The first electromagnetic directional valve includes a first liquid port, a second liquid port, and a third liquid port. The first liquid port is connected to the hydraulic accumulator, the second liquid port is connected to the walking system, and the third liquid port is connected to the working system. When the controller controls the first electromagnetic directional valve to be in a first working state, the first liquid port is connected to the second liquid port. When the controller controls the first electromagnetic directional valve to be in a second working state, the first liquid port is connected to the third liquid port. In this case, step S2 includes: when the load power of the walking system is greater than the maximum power of the first motor, controlling the first solenoid directional valve to enter a first working state; step S3 includes: when the load power of the working system is greater than the maximum power of the second motor, controlling the first solenoid directional valve to enter a second working state; step S4 includes: when the walking system is in a deceleration or braking state, controlling the first solenoid directional valve to enter the first working state, so that the hydraulic accumulator receives the oil returned by the walking system, thereby realizing energy recovery; step S5 includes: when the working system is in a deceleration or load lowering state, controlling the first solenoid directional valve to enter the second working state, so that the hydraulic accumulator receives the oil returned by the working system, thereby realizing energy recovery.

[0030] In an optional embodiment of this application, the above method further includes: when the working system is in a deceleration or load-lowering state, if the pressure in the hydraulic accumulator is greater than a preset pressure threshold, the first electromagnetic directional valve is controlled to first enter a first working state to release oil to the walking system, and then the first electromagnetic directional valve is controlled to enter a second working state, so that the hydraulic accumulator receives the oil returned by the working system and realizes energy recovery.

[0031] In an optional embodiment of this application, the walking system is further provided with a pressure sensor for monitoring the hydraulic state in the connecting pipe between the hydraulic accumulator and the first liquid port, and a flow sensor for monitoring the oil flow rate in the connecting pipe between the hydraulic accumulator and the first liquid port; the working system is further provided with a displacement sensor for monitoring the displacement state of the piston rod of the working hydraulic cylinder; the pressure sensor, the flow sensor, and the displacement sensor are respectively electrically connected to the controller. In this case, step S1 includes: adjusting the working power of the first motor and / or the second motor according to the displacement parameters fed back by the displacement sensor, the hydraulic parameters fed back by the pressure sensor, and the flow parameters fed back by the flow sensor.

[0032] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, optional embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a structural schematic diagram of a hybrid power system for engineering machinery provided in this application; Figure 2 This is a flowchart illustrating a control method for a hybrid power system of engineering machinery provided in this application; Figure 3 This application provides a load curve and a displacement curve for a hydraulic cylinder used in operation. Detailed Implementation

[0035] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0036] Firstly, such as Figure 1 As shown, this application provides a hybrid power system for construction machinery, including a walking system 100, a working system 200, an energy storage auxiliary system 300, and a controller 20.

[0037] The walking system 100 includes a first motor 1, a hydraulic motor 6, and wheels 10. The first motor 1 and the hydraulic motor 6 drive the wheels 10 to rotate through mechanical components.

[0038] The working system 200 includes a second motor 11, a hydraulic pump 12, and a working hydraulic cylinder 18. The second motor 11 drives the hydraulic pump 12 to deliver oil to the rodless chamber or rod chamber of the working hydraulic cylinder 18, so that the piston rod of the working hydraulic cylinder 18 moves to perform the operation.

[0039] Both the first motor 1 and the second motor 11 are electrically connected to the controller 20. Therefore, the controller 20 can control the speed of the first motor 1 and the second motor 11.

[0040] The energy storage auxiliary system 300 includes a hydraulic accumulator 2, which selectively supplies or recovers oil to the walking system 100 or the working system 200 under the control of the controller 20.

[0041] When the hybrid power system of the construction machinery is in light-load electric drive mode, the load is small. The walking system 100 is mainly driven by the first motor 1, and the working system 200 is mainly driven by the second motor 11 to power the hydraulic pump 12. The hydraulic accumulator 2 is in a holding state. The controller 20 controls the driving speed and actuator speed by adjusting the speed of the first motor 1 and the second motor 11.

[0042] When the hybrid power system of the construction machinery is in heavy-load hybrid drive mode: the load is large. If the load power of the subsystem exceeds the maximum power of the motor, the controller 20 controls the hydraulic accumulator 2 to selectively supplement the power to the corresponding subsystem, which significantly reduces the demand for instantaneous power of the motor.

[0043] During the energy recovery phase, such as when the hydraulic cylinder 18 is lowered or the walking system 100 is decelerated and braked, energy flows back to the accumulator or motor / battery through the regeneration path, supporting two paths: motor power generation to battery charging and hydraulic energy direct compression of the accumulator.

[0044] It is understood that the hybrid power system for construction machinery disclosed in this application has the following beneficial effects: First, it addresses the challenges of large installed power and high peak demand by utilizing energy storage devices to compensate for short-term high power demand, thereby reducing the rated power of the motor and decreasing equipment size, cost, and energy consumption; second, it solves the problem of insufficient energy recovery and utilization by recovering instantaneous energy through regeneration paths, reducing waste; and third, it improves the problem of insufficient energy coordination among multiple subsystems by achieving unified and efficient energy allocation and dynamic coordination based on a shared energy source under different high power demands of subsystems.

[0045] In optional embodiments of this application, reference continues to be made to... Figure 1The energy storage auxiliary system 300 also includes a first electromagnetic directional valve 5 electrically connected to the controller 20. The first electromagnetic directional valve 5 includes a first liquid port 51, a second liquid port 52, and a third liquid port 53. The first liquid port 51 is connected to the hydraulic accumulator 2, the second liquid port 52 is connected to the walking system 100, and the third liquid port 53 is connected to the working system 200. When the controller 20 controls the first electromagnetic directional valve 5 to be in a first working state, the first liquid port 51 is connected to the second liquid port 52. When the controller 20 controls the first electromagnetic directional valve 5 to be in a second working state, the first liquid port 51 is connected to the third liquid port 53.

[0046] It is understood that when the load power of the walking system 100 exceeds the maximum power of the first motor 1, the controller 20 controls the first solenoid directional valve 5 to enter the first working state. In the first working state, the oil in the hydraulic accumulator 2 is supplied to the walking system 100 through the first port 51 and the second port 52, thereby increasing the power of the walking system. When the wheels brake or slow down, the oil in the walking system 100 returns to the hydraulic accumulator 2 through the second port 52 and the first port 51, completing energy recovery. In addition, when the wheels brake or slow down, the energy of the walking system 100 can also be recovered into the first motor 1 and the battery connected to the first motor 1.

[0047] It is understandable that when the load power of the operating system 200 exceeds the maximum power of the second motor 11, the controller 20 controls the first solenoid directional valve 5 to enter the second operating state. In the second operating state, the hydraulic accumulator 2 supplies oil to the operating system 200 through the first port 51 and the third port 53, thereby increasing the power of the operating system. Figure 3 For example, the hydraulic cylinder starts lifting the load in about 30 seconds. At this time, the required power is relatively large. If it exceeds the maximum power of the second motor 11, the energy storage auxiliary system 300 needs to provide operation assistance at this time and deliver oil to the operation system 200.

[0048] It is understandable that when the hydraulic cylinder stops lifting or lowering the load, the oil in the working system 200 returns to the hydraulic accumulator 2 through the third port 53 and the first port 51, completing energy recovery. Figure 3 For example, when the hydraulic cylinder starts to reduce the load at around 45 seconds, the oil may return to the hydraulic accumulator 2 via the original path, which may cause the oil pressure in the hydraulic accumulator 2 to be too high. Therefore, the controller can control the first solenoid directional valve 5 to first enter the first working state, release the oil to the walking system 100, and then control the first solenoid directional valve 5 to enter the second working state, so that the hydraulic accumulator 2 receives the oil returned by the working system 200, thereby realizing energy recovery.

[0049] In optional embodiments of this application, reference continues to be made to... Figure 1The walking system 100 is also equipped with a pressure sensor 3 for monitoring the hydraulic state in the connecting pipe between the hydraulic accumulator 2 and the first liquid port 51, and a flow sensor 4 for monitoring the oil flow rate in the connecting pipe between the hydraulic accumulator 2 and the first liquid port 51; the working system 200 is also equipped with a displacement sensor 19 for monitoring the displacement state of the piston rod of the working hydraulic cylinder 18; the pressure sensor 3, the flow sensor 4 and the displacement sensor 19 are electrically connected to the controller 20, and the controller 20 controls the first solenoid directional valve 5 according to the feedback parameters of the pressure sensor 3, the flow sensor 4 and the displacement sensor 19.

[0050] It is understood that the controller 20 adjusts the working power of the first motor 1 and / or the second motor 11 based on the displacement parameters fed back by the displacement sensor 19, the hydraulic parameters fed back by the pressure sensor 3, and the flow parameters fed back by the flow sensor 4, thereby achieving precise control of the travel speed and the speed of the working hydraulic cylinder 18.

[0051] In optional embodiments of this application, reference continues to be made to... Figure 1 The walking system 100 also includes a first gear assembly 81 and a second gear assembly 82 that mesh with each other. The first motor 1 drives the wheel 10 to rotate through the first gear assembly 81, and the hydraulic motor 6 drives the second gear assembly 82 to rotate, thereby driving the first gear assembly 81 to drive the wheel 10 to rotate through the meshing relationship. The walking system 100 also includes a first oil tank 7. The inlet of the hydraulic motor 6 is connected to the second oil port 52, and the outlet of the hydraulic motor 6 is connected to the first oil tank 7.

[0052] It is understood that the walking system 100 in this application is a parallel power system, in which the first motor 1 and the hydraulic motor 6 jointly drive the wheels 10. When encountering scenarios where the load is heavy or the driving speed increases, the hydraulic accumulator 2 supplies oil to the hydraulic motor 6 through the second liquid port 52, and the first motor 1 and the hydraulic motor 6 simultaneously provide power to the transmission mechanism. Once the load is reduced or the driving speed reaches the cruising speed, the hydraulic accumulator 2 no longer supplies oil to the hydraulic motor 6, and the construction machinery equipment only needs to rely on the first motor 1 to maintain the speed.

[0053] In optional embodiments of this application, reference continues to be made to... Figure 1The working system 200 also includes a second oil tank 20 and a second solenoid directional valve 17. The second solenoid directional valve 17 includes a fourth port 171, a fifth port 172, a sixth port 173, and a seventh port 174. The fourth port 171 is connected to the outlet of the hydraulic pump 12 and is also connected to a third port 53. The fifth port 172 is connected to the rod chamber of the working hydraulic cylinder 18, the sixth port 173 is connected to the rodless chamber of the working hydraulic cylinder 18, and the seventh port 174... 74 is connected to the inlet of hydraulic pump 12, and the inlet of hydraulic pump 12 is also connected to the second oil tank 20; when controller 20 controls the second solenoid directional valve 17 to be in the third working state, the fourth port 171 is connected to the sixth port 173, and the fifth port 172 is connected to the seventh port 174; when controller 20 controls the second solenoid directional valve 17 to be in the fourth working state, the fourth port 171 is connected to the fifth port 172, and the sixth port 173 is connected to the seventh port 174.

[0054] It can be understood that when the controller 20 controls the second solenoid directional valve 17 to be in the third working state, the hydraulic pump 12 draws oil from the second oil tank 20 and delivers it to the rodless chamber of the working hydraulic cylinder 18, thereby pushing the piston rod to extend. Excess oil in the rod chamber returns to the second oil tank 20 through the fifth port 172 and the seventh port 174. During this process, if the load power of the working system 200 is greater than the maximum power of the second motor 11, the hydraulic accumulator 2 delivers oil to the rodless chamber through the third port 53 to increase the working power of the piston rod. When the controller 20 controls the second solenoid directional valve 17 to be in the fourth working state, the hydraulic pump 12 draws oil from the second oil tank 20 and delivers it to the rod chamber of the working hydraulic cylinder 18, thereby squeezing the piston rod to retract. Excess oil in the rodless chamber returns to the second oil tank 20 through the sixth port 173 and the seventh port 174. It can be seen that the controller 20 can control the reciprocating motion of the piston rod by controlling the second solenoid directional valve 17.

[0055] In optional embodiments of this application, reference continues to be made to... Figure 1 The rod chamber of the working hydraulic pump 12 is also connected to the second oil tank 20. A third check valve 16 is also provided on the oil pipe connecting the rod chamber and the second oil tank 20 to prevent oil from flowing into the second oil tank 20.

[0056] It is understood that when the controller 20 controls the second solenoid directional valve 17 to be in the third working state, if the currently operating hydraulic cylinder 18 is lowered, the energy recovery stage is entered, and the oil in the rodless chamber returns to the hydraulic accumulator 2 through the sixth port 173 and the fourth port 171; the third check valve 16 is used to prevent the oil from flowing to the second oil tank 20 and to ensure that the oil returns to the hydraulic accumulator 2; at this time, the second oil tank 20 replenishes the oil to the rod chamber through the seventh port 174 and the fifth port 172.

[0057] In optional embodiments of this application, reference continues to be made to... Figure 1 An overflow valve 14 is also provided between the inlet and outlet of the hydraulic pump 12. It can be understood that when the system pressure exceeds the set value, the overflow valve 14 opens, allowing excess oil to flow back to the second oil tank 20, preventing the system pressure from being too high and damaging the components, thus playing a role in protecting the system, maintaining pressure stability, and ensuring safe and reliable operation.

[0058] In optional embodiments of this application, reference continues to be made to... Figure 1 A first check valve 13 is provided on the oil pipe connecting the outlet of the hydraulic pump 12 and the fourth port 171 to prevent oil from flowing into the hydraulic pump 12.

[0059] In optional embodiments of this application, reference continues to be made to... Figure 1 A second check valve 15 is installed on the oil pipe connecting the inlet of the hydraulic pump 12 and the seventh port 174 to prevent oil from flowing to the seventh port 174.

[0060] Secondly, this application discloses a control method for a hybrid power system of engineering machinery, applicable to any of the hybrid power systems of engineering machinery described in the first aspect, such as... Figure 2 As shown, the method includes the following steps S1 to S3. Here, S1, S2, etc., are merely step identifiers; the execution order of the method does not necessarily follow an ascending numerical order. For example, step S2 may be executed first, followed by step S1. This application does not impose any restrictions.

[0061] S1 controls the operating power of the first motor and / or the second motor to drive the walking system or the working system.

[0062] It is understandable that the controller precisely adjusts the speed and output power of the first motor (driving the walking system) and the second motor (driving the working system) according to the actual working conditions of the construction machinery, such as the travel speed or the speed requirements of the hydraulic cylinder. Under light loads, the motor can drive the equipment alone; while under heavy loads or in scenarios requiring high power output, the motor power is increased to the rated power and combined with the energy storage auxiliary system to achieve efficient and stable operation of walking and working, ensuring the optimal balance between equipment power performance and energy consumption.

[0063] S2, when the load power of the walking system is greater than the maximum power of the first motor, controls the hydraulic accumulator to deliver oil to the walking system to assist the walking system in increasing its power.

[0064] It is understandable that when the load power of the walking system exceeds the maximum power of the first motor, the hydraulic accumulator connects to the walking system and delivers high-pressure oil to the walking system, providing additional power to the hydraulic motor and assisting the first motor in driving the wheels to rotate. This process significantly improves the instantaneous power of the walking system, ensuring that the equipment can still maintain stable operation under high power demand scenarios such as heavy loads or climbing, while avoiding motor overload damage.

[0065] S3, when the load power of the working system is greater than the maximum power of the second motor, controls the hydraulic accumulator to deliver oil to the working system to assist the working system in increasing its power.

[0066] S4 controls the hydraulic accumulator to connect with the walking system when the walking system is in a deceleration or braking state, so as to receive the oil returned by the walking system and realize energy recovery.

[0067] S5 controls the hydraulic accumulator to connect with the working system when the working system is decelerating or lowering the load, so as to receive the oil returned by the working system and realize energy recovery.

[0068] It is understandable that when the load power of the working system exceeds the maximum capacity of the second motor, the controller immediately connects the hydraulic accumulator to the working system, injecting high-pressure oil into the rodless chamber of the working hydraulic cylinder, significantly increasing the thrust output of the piston rod. This process, through the instantaneous release of hydraulic energy by the accumulator, effectively compensates for insufficient motor power, ensuring the continuity of heavy-duty operations such as loading and lifting, while preventing the motor from operating under overload.

[0069] In optional embodiments of this application, reference is made to Figure 1 The energy storage auxiliary system 300 also includes a first electromagnetic directional valve 5 electrically connected to the controller 20. The first electromagnetic directional valve 5 includes a first liquid port 51, a second liquid port 52, and a third liquid port 53. The first liquid port 51 is connected to the hydraulic accumulator 2, the second liquid port 52 is connected to the walking system 100, and the third liquid port 53 is connected to the working system 200. When the controller 20 controls the first electromagnetic directional valve 5 to be in a first working state, the first liquid port 51 is connected to the second liquid port 52. When the controller 20 controls the first electromagnetic directional valve 5 to be in a second working state, the first liquid port 51 is connected to the third liquid port 53.

[0070] In this case, step S2 includes: when the load power of the walking system is greater than the maximum power of the first motor, controlling the first electromagnetic reversing valve to enter the first working state.

[0071] In this case, step S3 includes: when the load power of the operating system is greater than the maximum power of the second motor, controlling the first solenoid directional valve to enter the second working state.

[0072] In this case, step S4 includes: when the walking system is in a deceleration or braking state, controlling the first electromagnetic reversing valve to enter the first working state, so that the hydraulic accumulator receives the oil returned by the walking system to realize energy recovery; In this case, step S5 includes: when the working system is in a deceleration or load-lowering state, controlling the first solenoid directional valve to enter the second working state, so that the hydraulic accumulator receives the oil returned by the working system to realize energy recovery.

[0073] In optional embodiments of this application, the above method further includes: when the working system is in a deceleration or load-lowering state, if the pressure inside the hydraulic accumulator is greater than a preset pressure threshold, the first solenoid directional valve is controlled to first enter a first working state to release oil to the walking system, and then the first solenoid directional valve is controlled to enter a second working state, so that the hydraulic accumulator receives the oil returned by the working system and realizes energy recovery.

[0074] In optional embodiments of this application, reference continues to be made to... Figure 1 The walking system 100 is also equipped with a pressure sensor 3 for monitoring the hydraulic state in the connecting pipe between the hydraulic accumulator 2 and the first liquid port 51, and a flow sensor 4 for monitoring the oil flow rate in the connecting pipe between the hydraulic accumulator 2 and the first liquid port 51; the working system 200 is also equipped with a displacement sensor 19 for monitoring the displacement state of the piston rod of the working hydraulic cylinder 18; the pressure sensor 3, the flow sensor 4 and the displacement sensor 19 are electrically connected to the controller 20 respectively.

[0075] In this case, step S1 includes: adjusting the operating power of the first motor and / or the second motor based on the displacement parameters fed back by the displacement sensor, the hydraulic parameters fed back by the pressure sensor, and the flow parameters fed back by the flow sensor.

[0076] It is understood that this embodiment, by setting pressure sensor 3, flow sensor 4, and displacement sensor 19, can accurately monitor the hydraulic state, oil flow rate, and piston rod displacement in real time. The controller 20 dynamically adjusts the working power of the first motor and / or the second motor based on these feedback parameters, achieving precise control of the travel speed and the speed of the working hydraulic cylinder 18. This helps optimize the equipment's power performance, avoid motor overload or power waste, improve system energy efficiency and operational stability, and enhance the equipment's adaptability to complex working conditions.

[0077] The terms "first," "second," "first," or "second" as used in the various embodiments of this disclosure may modify various components regardless of their order and / or importance, but these terms do not limit the corresponding components. The above terms are configured only for the purpose of distinguishing an element from other elements. For example, "first user equipment" and "second user equipment" refer to different user equipments, although both are user equipment. For example, without departing from the scope of this disclosure, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

[0078] When a component (e.g., a first component) is referred to as being "(operably or communicatively) coupled" or "(operably or communicatively) coupled to" or "connected to" another component (e.g., a second component), it should be understood that the first component is directly connected to the second component or that the first component is indirectly connected to the second component via yet another component (e.g., a third component). Conversely, it can be understood that when a component (e.g., a first component) is referred to as being "directly connected" or "directly coupled" to another component (the second component), no component (e.g., a third component) is inserted between the two.

[0079] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, components, features, and elements with the same names in different embodiments of this application may have the same meaning or different meanings, the specific meaning of which must be determined by its interpretation in that specific embodiment or further in conjunction with the context of that specific embodiment.

[0080] The above description is merely an optional embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in this application.

[0081] Depending on the context, the words “if” or “suppose” as used here can be interpreted as “when” or “in response to determination” or “in response to detection.” Similarly, depending on the context, the phrases “if determination” or “if detection (of the stated condition or event)” can be interpreted as “when determination” or “in response to determination” or “when detection (of the stated condition or event)” or “in response to detection (of the stated condition or event).”

[0082] The above description is merely an optional embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in this application.

[0083] The above description is merely an optional embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A control method for a hybrid power system of engineering machinery, applied to a hybrid power system of engineering machinery, characterized in that, The hybrid power system for the construction machinery includes a walking system, an operating system, an energy storage auxiliary system, and a controller; The walking system includes a first motor, a hydraulic motor, and wheels, wherein the first motor and the hydraulic motor respectively drive the wheels to rotate through mechanical components; The working system includes a second motor, a hydraulic pump, and a working hydraulic cylinder. The second motor drives the hydraulic pump to deliver oil to the rodless chamber or the rod chamber of the working hydraulic cylinder, so that the piston rod of the working hydraulic cylinder moves to perform the operation. Both the first motor and the second motor are electrically connected to the controller; The energy storage auxiliary system includes a hydraulic accumulator, which, under the control of the controller, selectively supplies or recovers hydraulic fluid to the walking system or the working system. The method includes the following steps: S1, control the operating power of the first motor and / or the second motor to drive the walking system or the working system to operate; S2, when the load power of the walking system is greater than the maximum power of the first motor, control the hydraulic accumulator to deliver oil to the walking system to assist the walking system in increasing its power; S3, when the load power of the working system is greater than the maximum power of the second motor, control the hydraulic accumulator to supply oil to the working system to assist the working system in increasing its power; S4, when the walking system is in a deceleration or braking state, control the hydraulic accumulator to connect with the walking system, receive the oil returned by the walking system, and realize energy recovery; S5, when the working system is in a deceleration or load-lowering state, control the hydraulic accumulator to connect with the working system, receive the oil returned by the working system, and realize energy recovery; The energy storage auxiliary system also includes a first electromagnetic reversing valve electrically connected to the controller. The first electromagnetic reversing valve includes a first liquid port, a second liquid port, and a third liquid port. The first liquid port is connected to the hydraulic accumulator, the second liquid port is connected to the walking system, and the third liquid port is connected to the working system. When the controller controls the first electromagnetic reversing valve to be in a first working state, the first liquid port is connected to the second liquid port; when the controller controls the first electromagnetic reversing valve to be in a second working state, the first liquid port is connected to the third liquid port. When the working system is in a deceleration or load-lowering state, if the pressure in the hydraulic accumulator is greater than a preset pressure threshold, the first solenoid directional valve is controlled to first enter the first working state to release oil to the walking system, and then the first solenoid directional valve is controlled to enter the second working state, so that the hydraulic accumulator receives the oil returned by the working system and realizes energy recovery.

2. The control method for a hybrid power system of engineering machinery according to claim 1, characterized in that, S2 includes: when the load power of the walking system is greater than the maximum power of the first motor, controlling the first electromagnetic reversing valve to enter a first working state; S3 includes: when the load power of the working system is greater than the maximum power of the second motor, controlling the first electromagnetic reversing valve to enter the second working state; S4 includes: when the walking system is in a deceleration or braking state, controlling the first electromagnetic reversing valve to enter a first working state, so that the hydraulic accumulator receives the oil returned by the walking system to realize energy recovery; S5 includes: when the working system is in a deceleration or load-lowering state, controlling the first electromagnetic reversing valve to enter a second working state, so that the hydraulic accumulator receives the oil returned by the working system to realize energy recovery.

3. The control method for a hybrid power system of engineering machinery according to claim 1, characterized in that, The walking system is also equipped with a pressure sensor to monitor the hydraulic state in the connecting pipe between the hydraulic accumulator and the first liquid port, and a flow sensor to monitor the oil flow rate in the connecting pipe between the hydraulic accumulator and the first liquid port; the working system is also equipped with a displacement sensor to monitor the displacement state of the piston rod of the working hydraulic cylinder. The pressure sensor, the flow sensor, and the displacement sensor are electrically connected to the controller, and the controller adjusts the operating power of the first motor and / or the second motor according to the feedback parameters of the pressure sensor, the flow sensor, and the displacement sensor. S1 includes: The operating power of the first motor and / or the second motor is adjusted based on the displacement parameters fed back by the displacement sensor, the hydraulic parameters fed back by the pressure sensor, and the flow parameters fed back by the flow sensor.

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