Oil-electric hydraulic multi-power hybrid system for oil-hybrid vehicles and walking construction machines

Abstract

The application provides an oil-electric-hydraulic multi-power hybrid system of an oil hybrid vehicle and a walking engineering machine, and the recovery of walking braking energy in a braking condition is realized in an electrical type based on an electric generator, a hydraulic type based on a hydraulic pump motor and a composite type based on an electric generator-hydraulic pump motor, so that the braking energy can be recovered in a wide range and with high efficiency, and the braking energy recovery efficiency is greatly improved; in a driving condition, power is provided in various forms such as engine single driving, hydraulic pump motor single driving, electric generator single driving, engine-hydraulic pump motor combined driving, engine-electric generator combined driving, hydraulic pump motor-electric generator combined driving and engine-hydraulic pump motor-electric generator combined driving, so that the use of the engine is reduced through various single driving modes, and the engine can be stably operated in an economic condition for a long time through various combined driving modes, the fuel economy of the whole vehicle is greatly improved, and the energy-saving and emission-reducing effect is remarkable.

Description

Technical Field

[0001] This invention relates to the field of hybrid power systems for mobile construction machinery, specifically to hybrid electric vehicles and hybrid electric-hydraulic systems for mobile construction machinery. Background Technology

[0002] When heavy-duty mobile construction machinery travels on urban roads, due to its heavy weight, high installed power, and frequent start-stop cycles, the engine often operates under low load, resulting in high fuel consumption and poor emissions. This also causes a significant amount of negative braking energy load to be wasted as heat. Therefore, current vehicle drive systems on the market include start-stop systems and brake energy recovery systems. Hybrid systems, with their energy storage units, lay the foundation for energy recovery from the negative braking energy load of mobile construction machinery. Hybrid power technology, with its high power density and rapid energy charging and discharging, has become the most effective way to achieve brake energy recovery in mobile construction machinery.

[0003] Existing hydraulic hybrid technology suffers from several limitations. When the high-pressure accumulator runs out of pressure energy, the vehicle cannot perform a pure hydraulic start at low speeds, severely impacting normal vehicle operation. Furthermore, the braking energy recovered in the hydraulic system is only sufficient for low-speed pure hydraulic start. When the recovered braking energy reaches the maximum pressure of the high-pressure accumulator, the excess braking energy cannot be used for the working devices of the construction machinery, resulting in waste. In short, the development of existing hydraulic hybrid technology is constrained by numerous limitations, including hydraulic accumulator technology bottlenecks, difficulty in reducing vehicle power output, high costs, low hydraulic transmission efficiency, and hydraulic fluid leakage and pollution. Hydraulic hybrid systems suffer from low energy density and limited space due to the low size of the hydraulic accumulator, resulting in limited energy recovery efficiency and low braking energy recovery efficiency. Simultaneously, the limited energy storage of hydraulic hybrid systems prevents long-term stable adjustment of engine operation for economical operation and makes it impossible to reduce engine power output, leading to poor energy saving and emission reduction effects.

[0004] In view of the above, this application is hereby submitted. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a hybrid power system for oil-hydraulic hybrid vehicles and mobile construction machinery, which can effectively solve the problem that the existing oil-hydraulic hybrid systems have low energy density and limited space due to the installation space of the hydraulic accumulator, resulting in limited energy storage space and thus low energy recovery efficiency during travel and braking.

[0006] This invention provides a hybrid power system for mobile engineering machinery, comprising a vehicle controller, a power coupling component, a main power component, a first auxiliary power component, a second auxiliary power component, a second clutch, a third clutch, and a fourth clutch;

[0007] The output shaft of the main power component is connected to the input shaft of the power coupling component. The first auxiliary power component is connected to the input shaft of the power coupling component via the third clutch. The second auxiliary power component is connected to the input shaft of the power coupling component via the second clutch. The first auxiliary power component is connected to the second auxiliary power component via a pipeline through the four-clutch. The output terminal of the vehicle controller is electrically connected to the control terminals of the main power component, the first auxiliary power component, and the second auxiliary power component. The input terminal of the vehicle controller is used to electrically connect to the pedals and sensors of the traveling construction machinery.

[0008] The vehicle controller is configured to perform the following steps by executing a computer program stored internally:

[0009] When the system is detected to be in a braking state, the SOC value of the hydraulic accumulator and the SOC value of the battery of the mobile construction machinery are acquired in real time, and the SOC values ​​of the hydraulic accumulator and the battery are compared with the corresponding preset values ​​to generate comparison results.

[0010] When it is determined from the comparison result that only the hydraulic accumulator is in a recyclable state, the first auxiliary power component is controlled to convert the braking energy generated by the power coupling component into hydraulic energy and store it.

[0011] When it is determined from the comparison result that only the battery is in a recyclable state, the first auxiliary power component and the second auxiliary power component are controlled to convert the braking energy generated by the power coupling component into electrical energy and store it.

[0012] When it is determined from the comparison results that both the hydraulic accumulator and the battery are in a recyclable state, the first auxiliary power component is first controlled to convert the braking energy generated by the power coupling component into hydraulic energy and store it. When the SOC value of the hydraulic accumulator is detected that the energy recovery of the hydraulic accumulator is complete, the first auxiliary power component and the second auxiliary power component are controlled to convert the braking energy generated by the power coupling component into electrical energy and store it.

[0013] Preferably, it further includes:

[0014] When the system is detected to be in driving mode, the SOC value of the hydraulic accumulator and the SOC value of the battery of the mobile construction machinery are acquired in real time, and the SOC values ​​of the hydraulic accumulator and the battery are compared with the corresponding preset values ​​to generate comparison results.

[0015] When it is determined from the comparison result that only the hydraulic accumulator is in a state where it can release energy, the first auxiliary power component is controlled to drive the power coupling component to rotate.

[0016] When it is determined from the comparison result that only the battery is in a dischargeable state, the second auxiliary power component is controlled to drive the power coupling component to rotate.

[0017] When it is determined from the comparison results that the hydraulic accumulator is not in a state where it can release energy and the battery is not in a state where it can discharge energy, the active power component is controlled to drive the power coupling component to rotate.

[0018] Preferably, the power coupling assembly includes a first torque coupler, a second torque coupler, a gearbox, a drive axle, and drive wheels;

[0019] The output shaft of the main power component is connected to the input shaft of the second torque coupler, the first output shaft of the second torque coupler is connected to the input shaft of the gearbox, the second output shaft of the second torque coupler is connected to the input shaft of the first torque coupler, the first output shaft of the first torque coupler is connected to the input shaft of the first auxiliary power and the input shaft of the second auxiliary power component, the output shaft of the gearbox is connected to the drive axle, and the drive axle is connected to the drive wheel.

[0020] Preferably, the system further includes a braking device configured on the drive wheel, and the output terminal of the vehicle controller is electrically connected to the control terminal of the braking device.

[0021] Preferably, the powertrain includes an engine and a first clutch, wherein the output shaft of the engine is connected to the input shaft of the first torque coupler via the first clutch, and the output terminal of the vehicle controller is electrically connected to the control terminal of the first clutch.

[0022] Preferably, the first auxiliary power assembly includes a third clutch, a second hydraulic pump motor, a first hydraulic pump motor, a fourth clutch, a hydraulic oil tank, a one-way valve, a two-position two-way solenoid directional valve, and a hydraulic accumulator.

[0023] In this configuration, the first output shaft of the first torque coupler is connected to the second auxiliary power assembly; the second output shaft of the first torque coupler is connected to the second hydraulic pump motor via the third clutch; the first hydraulic pump motor is connected to the second auxiliary power assembly via the fourth clutch; the first hydraulic pump motor and the second hydraulic pump motor are connected in parallel; the low-pressure oil circuit of the second hydraulic pump motor is connected to the hydraulic oil tank; the high-pressure oil circuit of the second hydraulic pump motor is connected to the hydraulic accumulator via the two-position two-way solenoid directional valve and the one-way valve; and the output terminal of the vehicle controller is electrically connected to the control terminals of the third clutch, the first hydraulic pump motor, the second hydraulic pump motor, the two-position two-way solenoid directional valve, and the fourth clutch.

[0024] Preferably, the second auxiliary power assembly includes a second clutch, an electric generator, a third torque coupler, and a battery. The first output shaft of the first torque coupler is connected to the third torque coupler via the second clutch. The first output shaft of the third torque coupler is connected to the electric generator. The second output shaft of the third torque coupler is connected to the first hydraulic pump motor via the fourth clutch. The electric generator is electrically connected to the battery. The output terminal of the vehicle controller is electrically connected to the control terminal of the second clutch.

[0025] Preferably, it further includes a first relief valve, the first port of which is connected to the hydraulic oil tank, and the second port of which is connected to the second hydraulic pump motor.

[0026] Preferably, the system further includes a second relief valve, the first port of which is connected to the hydraulic oil tank, and the second port of the first relief valve is connected to the hydraulic accumulator.

[0027] The present invention also provides a hybrid electric vehicle, including a mechanical body and a hybrid electric-hydraulic system for mobile construction machinery as described above, wherein the hybrid electric system for mobile construction machinery is configured on the mechanical body.

[0028] In summary, the hybrid electric vehicle and mobile construction machinery system provided in this embodiment can efficiently recover braking energy over a wide range during braking by employing a reasonable energy recovery strategy. During driving, a reasonable driving strategy can reduce engine usage or allow the engine to operate stably at its economic operating point for extended periods, significantly improving overall vehicle fuel economy and achieving remarkable energy conservation and emission reduction. This solves the problem of low energy recovery efficiency in existing hybrid electric systems due to the low energy density of hydraulic accumulators and the limited installation space, resulting in insufficient energy storage. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the hybrid hydraulic-electric-hydraulic system for mobile engineering machinery provided in an embodiment of the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to represent selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0032] Please see Figure 1 The first embodiment of the present invention provides a hybrid power system for mobile engineering machinery, including a vehicle controller 20, a power coupling component, a main power component, a first auxiliary power component, a second auxiliary power component, a second clutch 8, a third clutch 12, and a fourth clutch 23.

[0033] The output shaft of the main power component is connected to the input shaft of the power coupling component. The first auxiliary power component is connected to the input shaft of the power coupling component through the third clutch 12. The second auxiliary power component is connected to the input shaft of the power coupling component through the second clutch 8. The first auxiliary power component is connected to the second auxiliary power component through the four-clutch 23. The output terminal of the vehicle controller 20 is electrically connected to the control terminal of the main power component, the control terminal of the first auxiliary power component, and the control terminal of the second auxiliary power component. The input terminal of the vehicle controller 20 is used to electrically connect to the pedals and sensors of the traveling construction machinery.

[0034] The vehicle controller 20 is configured to perform the following steps by executing a computer program stored internally:

[0035] When the system is detected to be in a braking state, the SOC value of the hydraulic accumulator and the SOC value of the battery of the mobile construction machinery are acquired in real time, and the SOC values ​​of the hydraulic accumulator and the battery are compared with the corresponding preset values ​​to generate comparison results.

[0036] When it is determined from the comparison result that only the hydraulic accumulator is in a recyclable state, the first auxiliary power component is controlled to convert the braking energy generated by the power coupling component into hydraulic energy and store it.

[0037] When it is determined from the comparison result that only the battery is in a recyclable state, the first auxiliary power component and the second auxiliary power component are controlled to convert the braking energy generated by the power coupling component into electrical energy and store it.

[0038] When it is determined from the comparison results that both the hydraulic accumulator and the battery are in a recyclable state, the first auxiliary power component is first controlled to convert the braking energy generated by the power coupling component into hydraulic energy and store it. When the SOC value of the hydraulic accumulator is detected that the energy recovery of the hydraulic accumulator is complete, the first auxiliary power component and the second auxiliary power component are controlled to convert the braking energy generated by the power coupling component into electrical energy and store it.

[0039] The development of current hybrid electric vehicle technology is limited by many factors, including bottlenecks in hydraulic accumulator technology, difficulty in reducing vehicle power output, high cost, low hydraulic transmission efficiency, and hydraulic fluid leakage and pollution. Due to the low energy density of hydraulic accumulators and the limited installation space, hybrid electric vehicle systems cannot recover much energy, resulting in low energy recovery efficiency during driving and braking. At the same time, due to limited energy storage, hybrid electric vehicle systems cannot stably adjust the engine for economical operation for extended periods, nor can they reduce the engine power output, leading to poor energy saving and emission reduction effects.

[0040] Specifically, in this embodiment, the vehicle controller 20 controls the component states of the hybrid hydraulic-electric-hydraulic system of the mobile construction machinery to ensure its smooth operation. The vehicle controller 20 collects and processes signals such as feedback speed and torque signals from the electric generator controller, feedback speed and torque signals from the engine controller, gearbox gear position signals, clutch pedal opening signals, accelerator pedal opening signals, brake pedal opening signals, hydraulic system pressure sensor pressure feedback signals, hydraulic accumulator SOC signals, and battery SOC signals. It then identifies the vehicle's operating mode and autonomously switches to a suitable condition. Furthermore, it rationally allocates the power or torque of different power sources according to the vehicle control strategy, optimizing onboard energy to maximize the efficiency of the entire vehicle system. Simultaneously, it recovers and utilizes as much regenerative braking energy as possible, ensuring the engine always operates within its efficient operating range to reduce fuel consumption and exhaust emissions. The vehicle controller 20 executes a predetermined control strategy, sending control signals to the motor controller, engine controller, two-position two-way solenoid directional valve, second, third and fourth clutches, first and second hydraulic pump motors, etc., thereby controlling the operating status of each component, ensuring the smooth operation of the hybrid hydraulic-electric-hydraulic system, and realizing various driving and braking working modes.

[0041] In this embodiment, the hybrid hydraulic-electric-hydraulic system for mobile construction machinery structurally includes a first primary power unit (engine), a second auxiliary power unit (hydraulic pump motor), and a third auxiliary power unit (electric generator). Its energy sources are a fuel tank, a hydraulic accumulator, and a battery, respectively. The system possesses a power-type energy storage unit (hydraulic accumulator) and an energy-type energy storage unit (battery). When the hybrid system is braking, it recovers braking energy through three methods: an electric method based on the electric generator, a hydraulic method based on the hydraulic pump motor, and a composite method based on both. This achieves large-scale, efficient recovery of braking energy, significantly improving braking energy recovery efficiency. In short, this system has high energy recovery efficiency, and the auxiliary power source can stably output power for extended periods. By stabilizing the engine's economic operating point through peak shaving and valley filling, the overall vehicle performance, including fuel economy, power, and handling, is greatly improved, resulting in significant energy saving and emission reduction. Simultaneously, the system is safe and reliable, with high energy recovery efficiency, greatly improving vehicle fuel economy and achieving significant energy saving and emission reduction. To a certain extent, this solves the problem of existing hydraulic hybrid power technology having low energy density in the hydraulic accumulator storage unit, resulting in insufficient energy storage and an inability to stably adjust the engine operating point for economical operation.

[0042] In this embodiment, because the hydraulic accumulator has a high power density, it is used first when the vehicle starts. Therefore, during the braking energy recovery process, hydraulic energy recovery is prioritized, and electrical auxiliary braking energy recovery is used. During hydraulic energy recovery, the hydraulic-hydraulic hybrid power system of the mobile construction machinery only needs to control the first auxiliary power component to work to perform energy conversion. However, during electrical braking energy recovery, the second auxiliary power component also needs energy from the first auxiliary power component. At this time, the system needs to control the first and second auxiliary power components to work simultaneously to perform energy conversion. Moreover, one energy recovery may not be able to fully store the hydraulic accumulator of the first auxiliary power component, which also wastes the system's energy to some extent.

[0043] In one possible embodiment of the present invention, it further includes:

[0044] When the system is detected to be in driving mode, the SOC value of the hydraulic accumulator and the SOC value of the battery of the mobile construction machinery are acquired in real time, and the SOC values ​​of the hydraulic accumulator and the battery are compared with the corresponding preset values ​​to generate comparison results.

[0045] When it is determined from the comparison result that only the hydraulic accumulator is in a state where it can release energy, the first auxiliary power component is controlled to drive the power coupling component to rotate.

[0046] When it is determined from the comparison result that only the battery is in a dischargeable state, the second auxiliary power component is controlled to drive the power coupling component to rotate.

[0047] When it is determined from the comparison results that the hydraulic accumulator is not in a state where it can release energy and the battery is not in a state where it can discharge energy, the active power component is controlled to drive the power coupling component to rotate.

[0048] Specifically, in this embodiment, when the hybrid hydraulic-electric-hydraulic system of the mobile construction machinery is in driving condition, it provides power in various forms, such as engine-only drive, hydraulic pump motor-only drive, electric generator-only drive, engine-hydraulic pump motor combined drive, engine-electric generator combined drive, hydraulic pump motor-electric generator combined drive, and engine-hydraulic pump motor-electric generator combined drive. By reducing engine usage through multiple individual drive methods and achieving stable engine operation under economic conditions for a long time through multiple combined drive methods, the fuel economy of the entire vehicle is greatly improved, and the energy saving and emission reduction effects are significant.

[0049] In one possible embodiment of the present invention, the power coupling assembly includes a first torque coupler 2, a second torque coupler 4, a gearbox 5, a drive axle 6, and a drive wheel 7;

[0050] The output shaft of the main power component is connected to the input shaft of the second torque coupler 4, the first output shaft of the second torque coupler 4 is connected to the input shaft of the gearbox 5, the second output shaft of the second torque coupler 4 is connected to the input shaft of the first torque coupler 2, the first output shaft of the first torque coupler 2 is connected to the input shaft of the first auxiliary power and the input shaft of the second auxiliary power component, the output shaft of the gearbox 5 is connected to the drive axle 6, and the drive axle 6 is connected to the drive wheel 7.

[0051] Specifically, in this embodiment, the first torque coupler 2 and the second torque coupler 4 can be gear-type torque couplers. A gear-type torque coupler can be simply understood as a clutch, although its principle and structure are more complex than a regular clutch. The gearbox 5, the drive axle 6, and the drive wheel 7 can be considered as a transmission system. A transmission system refers to the device that transmits power from a power source such as the engine to the drive wheels of the vehicle. The basic function of the transmission system is to receive power from the engine and transmit it to the drive wheels. In addition, it can also increase the torque from the engine; reduce the engine's output speed; change the direction of the engine's output speed; and cut off the transmission of engine power to the drive wheels. It should be noted that in other embodiments, other types of first and second torque couplers can also be used. No specific limitations are made here, but these solutions are all within the protection scope of this invention.

[0052] In one possible embodiment of the present invention, a braking device 21 is also included, which is disposed on the drive wheel 7, and the output terminal of the vehicle controller 20 is electrically connected to the control terminal of the braking device 21.

[0053] Specifically, in this embodiment, the braking device 21 generates friction between the brake pads and the wheel drum or disc, and in the process of friction, it converts the kinetic energy of the car during driving into heat energy for consumption.

[0054] In one possible embodiment of the present invention, the power unit includes an engine 1 and a first clutch 3, wherein the output shaft of the engine 1 is connected to the input shaft of the first torque coupler 2 via the first clutch 3, and the output terminal of the vehicle controller 20 is electrically connected to the control terminal of the first clutch 3.

[0055] In one possible embodiment of the present invention, the first auxiliary power assembly includes a third clutch 12, a second hydraulic pump motor 13, a first hydraulic pump motor 10, a fourth clutch 23, a hydraulic oil tank 14, a one-way valve 16, a two-position two-way solenoid directional valve 17, and a hydraulic accumulator 19.

[0056] In this configuration, the first output shaft of the first torque coupler 2 is connected to the second auxiliary power assembly, the second output shaft of the first torque coupler 2 is connected to the second hydraulic pump motor 13 via the third clutch 12, the first hydraulic pump motor 10 is connected to the second auxiliary power assembly via the fourth clutch 23, the first hydraulic pump motor 10 and the second hydraulic pump motor 13 are connected in parallel, the low-pressure oil circuit of the second hydraulic pump motor 13 is connected to the hydraulic oil tank 14, the high-pressure oil circuit of the second hydraulic pump motor 13 is connected to the hydraulic accumulator 19 via the two-position two-way solenoid directional valve 17 and the one-way valve 16, and the output terminal of the vehicle controller 20 is electrically connected to the control terminal of the third clutch 12, the control terminal of the first hydraulic pump motor 10, the control terminal of the second hydraulic pump motor 13, the control terminal of the two-position two-way solenoid directional valve 17, and the control terminal of the fourth clutch 23.

[0057] In one possible embodiment of the present invention, the second auxiliary power assembly includes a second clutch 8, an electric generator 9, a third torque coupler 22, and a battery 11. The first output shaft of the first torque coupler 2 is connected to the third torque coupler 22 via the second clutch 8. The first output shaft of the third torque coupler 22 is connected to the electric generator 9. The second output shaft of the third torque coupler 22 is connected to the first hydraulic pump motor 10 via the fourth clutch 23. The electric generator 9 is electrically connected to the battery 11. The output terminal of the vehicle controller 20 is electrically connected to the control terminal of the second clutch 8.

[0058] Specifically, in this embodiment, the third torque coupler 22 can be a gear-type torque coupler, and the first hydraulic pump motor 10 and the second hydraulic pump motor 13 can be variable displacement hydraulic pump motors. When the second hydraulic pump motor 13 is in pump mode, the hydraulic oil output by the hydraulic pump flows into the hydraulic accumulator 19 through the one-way valve 16, which is the charging process of the hydraulic accumulator 19. The hydraulic oil output by the hydraulic pump can also directly supply oil to the first hydraulic pump motor 10. At this time, the first hydraulic pump motor 10 is in motor mode. When the second hydraulic pump motor 13 is in motor mode, the two-position two-way solenoid directional valve 17 is opened, and the hydraulic accumulator 19 is connected to the main oil circuit to supply high-pressure oil to the hydraulic motor, which is the discharging process of the hydraulic accumulator 19.

[0059] When the first hydraulic pump motor 10 is in pump mode, the hydraulic oil output by the hydraulic pump flows into the hydraulic accumulator 19 through the one-way valve 16. The hydraulic oil output by the hydraulic pump can also directly supply oil to the second hydraulic pump motor 13. At this time, the second hydraulic pump motor 13 operates in motor mode. When the first hydraulic pump motor 10 is in motor mode, the fourth clutch 23 engages, driving the generator motor 9 to operate in generator mode through the third power coupling mechanism, and the generator charges the battery 11. When the electric generator 9 is in motor mode, the fourth clutch 23 engages, driving the first hydraulic pump motor 10 to operate in pump mode through the third power coupling mechanism; the second clutch 8 engages, the third power coupling mechanism connects to the first power coupling mechanism, and the motor is connected to the transmission system. This is the discharge process of the battery 11. It should be noted that in other embodiments, other types of third torque couplers, first hydraulic pump motors, and second hydraulic pump motors can also be used. No specific limitation is made here, but these solutions are all within the protection scope of this invention.

[0060] In this embodiment, when the hybrid hydraulic-electric-hydraulic system of the mobile construction machinery brakes, the engine 1 stops working, the first clutch 3 disengages, the gearbox 5 is in any gear, the third clutch 12 engages, the second torque coupler 4 and the first torque coupler 2 are connected to the transmission system, and the second hydraulic pump motor 13 starts operating as a pump; the second clutch 8 engages, the third torque coupler 22 is connected to the transmission system, the electric generator 9 operates as a generator, the hydraulic accumulator 19 charges, and the battery 11 is charged, thus realizing the recovery of vehicle braking energy. When the hybrid hydraulic-electric-hydraulic system of the mobile construction machinery is driven, the engine 1 starts working, the first clutch 3 engages, the second torque coupler 4 is connected to the transmission system, the second clutch 8 engages, the third torque coupler 22 and the electric generator 9 are connected to the transmission system; the third clutch 12 engages, the second hydraulic pump motor 13 is connected to the transmission system through the first torque coupler 2, the gearbox 5 is in a certain gear, the hydraulic accumulator 19 releases energy, and the battery 11 discharges, thus realizing the release of the recovered vehicle braking energy.

[0061] The specific working principle of this invention is as follows:

[0062] When the hybrid hydraulic-electric-hydraulic system of the mobile construction machinery brakes, the braking force is provided by mechanical friction braking, hydraulic regenerative braking, or electrical regenerative braking. When hydraulic or electrical regenerative braking participates in the braking process, energy recovery during vehicle movement is possible. During vehicle braking, regenerative braking is prioritized for energy recovery, with mechanical friction braking assisting. In emergency braking situations, mechanical friction braking is used directly, and regenerative braking is not involved.

[0063] First, the hydraulic accumulator recovers energy independently. The vehicle controller 20 monitors the SOC value of the hydraulic accumulator 19. When the SOC value is in a recoverable state, hydraulic energy recovery is performed. The vehicle controller 20 collects and processes the brake pedal opening signal to determine the required braking torque of the vehicle and allocates it appropriately. The vehicle controller 20 controls the engagement of the third clutch, and the first torque coupler 2 is connected to the transmission system. The torque of the drive wheel 7 drives the second hydraulic pump motor 13 to operate in pump mode via the drive axle 6, the gearbox 5, the second torque coupler 4, the first torque coupler 2, and the third clutch 12. The hydraulic pump draws oil from the hydraulic oil tank 14 and outputs hydraulic oil into the hydraulic accumulator 19 through the one-way valve 16, simultaneously generating regenerative braking torque to decelerate the drive wheel 7. In this way, the kinetic energy of the vehicle is converted into hydraulic energy in the hydraulic accumulator 19, completing the braking energy recovery process. The vehicle controller 20 controls the hydraulic pump to operate at maximum displacement to provide maximum braking torque and quickly recover braking energy. Insufficient braking force is supplemented by mechanical friction braking.

[0064] To accelerate the energy recovery process of the hydraulic accumulator 19 and reduce its charging time, the vehicle controller 20 engages the second clutch 8 and the fourth clutch 23. The first torque coupler 2 and the third torque coupler 22 are connected to the transmission system. The torque of the drive wheel 7 drives the first hydraulic pump motor 10 to operate in pump mode via the drive axle 6, the gearbox 5, the second torque coupler 4, the first torque coupler 2, the second clutch 8, the third torque coupler 22, and the fourth clutch 23. The hydraulic pump draws oil from the hydraulic oil tank 14 and outputs hydraulic oil into the hydraulic accumulator 19 through the one-way valve 16. Simultaneously, regenerative braking torque is generated to decelerate the drive wheel 7. The second hydraulic pump motor 13 and the first hydraulic pump motor 10 operate in pump mode, jointly participating in the regenerative braking process, generating a larger regenerative braking torque to decelerate the drive wheel 7 and accelerate the charging process of the hydraulic accumulator 19, thus achieving efficient braking energy recovery. If the regenerative braking torque is sufficient, the vehicle controller 20 adjusts the displacement of the first hydraulic pump motor 10 and the second hydraulic pump motor 13 to provide the required braking torque; if the regenerative braking torque is insufficient, the insufficient braking force will be supplemented by mechanical friction braking to ensure braking safety.

[0065] Secondly, the battery performs separate energy recovery. The vehicle controller 20 monitors the SOC value of the battery 11. When the SOC value is in a recyclable state, electrical energy recovery is performed. The vehicle controller 20 collects and processes the brake pedal opening signal to determine the required braking torque of the vehicle and allocates it appropriately. The vehicle controller 20 controls the second clutch 8 to engage, and the first torque coupler 2 and the third torque coupler 22 are connected to the transmission system. The torque of the drive wheel 7 drives the electric generator 9 to operate in generator mode via the drive axle 6, the gearbox 5, the second torque coupler 4, the first torque coupler 2, the second clutch 8, and the third torque coupler 22, thereby charging the battery 11.

[0066] To accelerate the energy recovery process of the battery 11 and reduce its charging time, the vehicle controller 20 controls the engagement of the third clutch 12 and the fourth clutch 23. The torque of the drive wheel 7 drives the second hydraulic pump motor 13 to operate in pump mode via the drive axle 6, the gearbox 5, the second torque coupler 4, the first torque coupler 2, and the third clutch 12. The hydraulic pump draws oil from the hydraulic oil tank 14 and outputs hydraulic oil to supply the first hydraulic pump motor 10 to operate in motor mode. The torque of the hydraulic motor drives the electric generator 9 to operate in generator mode via the fourth clutch 23 and the third torque coupler 22, thereby charging the battery 11.

[0067] Finally, a combined hydraulic accumulator-battery energy recovery process is implemented. The vehicle controller 20 monitors the SOC values ​​of the hydraulic accumulator 19 and the battery 11. When the SOC value is within a recoverable range, a combined hydraulic-electric energy recovery is performed. The vehicle controller 20 collects and processes the brake pedal opening signal to determine the required braking torque of the vehicle and allocates it appropriately. The vehicle controller 20 controls the engagement of the third clutch 12, the second clutch 8, and the fourth clutch 23. The second torque coupler 4, the first torque coupler 2, and the third torque coupler 22 are connected to the transmission system. The vehicle controller 20 controls the displacement of the first hydraulic pump motor 10 and the second hydraulic pump motor 13. The torque of the drive wheel 7 drives the second hydraulic pump motor 13 to operate in pump mode via the drive axle 6, the gearbox 5, the second torque coupler 4, the first torque coupler 2, and the third clutch 12. The hydraulic pump draws oil from the hydraulic oil tank 14 and outputs hydraulic oil, which flows into the hydraulic accumulator 19 through the one-way valve 16 for hydraulic energy recovery. The torque from the drive wheel 7, transmitted through the drive axle 6, the gearbox 5, the second torque coupler 4, the first torque coupler 2, the second clutch 8, and the third torque coupler 22, drives the electric generator 9 to operate in generator mode, thereby charging the battery 11 and performing electrical energy recovery. Hydraulic energy recovery and electrical energy recovery occur simultaneously. During energy recovery, the first hydraulic pump motor 10, operating in pump mode, can accelerate the charging process of the hydraulic accumulator 19; the first hydraulic pump motor 10, operating in motor mode, can accelerate the charging process of the battery 11. The first hydraulic pump motor 10 plays an auxiliary braking role in braking energy recovery, accelerating the energy recovery process and improving energy recovery efficiency.

[0068] When the hybrid hydraulic-electric-hydraulic system of the mobile construction machinery is driven, the driving force is provided by three power units: the engine 1, the second hydraulic pump motor 13, and the electric generator 9. During the driving process, the second hydraulic pump motor 13 and the electric generator 9 can release the energy recovered by the system. During system operation, the auxiliary power source is prioritized to provide power, reducing the use of the engine 1 or preventing it from operating in an inefficient range, thus contributing to energy conservation and emission reduction.

[0069] First, the engine drives the vehicle alone. When engine 1 is driven alone, the first clutch 3 is engaged via the clutch pedal. The torque of engine 1 drives the drive wheel 7 to rotate through the first clutch 3, the second torque coupler 4, the gearbox 5, and the drive axle 6, thus moving the vehicle. The process of engine 1 driving alone is the same as that of a traditional vehicle, and there is no energy saving or emission reduction effect. However, during the process of engine 1 driving alone, the excess power of engine 1 can be recovered through a hydraulic regeneration system and stored in a hydraulic accumulator, improving energy utilization efficiency.

[0070] Secondly, the second hydraulic pump motor is driven independently. The vehicle controller 20 monitors the SOC value of the hydraulic accumulator 19. After monitoring that the SOC value is in a state where energy can be released, the vehicle controller 20 collects and processes the accelerator pedal opening signal. When it determines that the regenerated driving force meets the driving force required by the vehicle, the second hydraulic pump motor 13 is driven independently. The vehicle controller 20 controls the third clutch 12 to engage, the first torque coupler 2 is connected to the transmission system, and the vehicle controller 20 controls the two-position two-way solenoid valve 17 to open. The hydraulic oil in the hydraulic accumulator 19 is supplied to the second hydraulic pump motor 13 through the two-position two-way solenoid valve 17. During motor operation, the torque of the hydraulic motor drives the drive wheel 7 to rotate through the third clutch 12, the first torque coupler 2, the second torque coupler 4, the gearbox 5, and the drive axle 6, thus moving the vehicle. During the independent driving of the second hydraulic pump motor 13, the engine 1 does not work, and the vehicle achieves energy saving and emission reduction effects.

[0071] Secondly, the electric generator 9 operates independently. The vehicle controller 20 monitors the SOC value of the battery 11. After detecting that the SOC value is in a dischargeable state, the vehicle controller 20 collects and processes the accelerator pedal opening signal. When it determines that the regenerative driving force meets the driving force required by the vehicle, the electric generator 9 operates independently. The vehicle controller 20 controls the second clutch 8 to engage, and the first torque coupler 2 and the third torque coupler 22 are connected to the transmission system. The battery 11 discharges to the electric generator 9, which operates under motor conditions. The motor torque drives the drive wheel 7 to rotate via the third torque coupler 22, the second clutch 8, the first torque coupler 2, the second torque coupler 4, the gearbox 5, and the drive axle 6, thus moving the vehicle. During the independent operation of the electric generator 9, the engine 1 does not work, and the vehicle achieves energy saving and emission reduction effects.

[0072] Finally, a combined drive system is implemented, comprising the combined drive of engine 1 and the second hydraulic pump motor 13, engine 1 and the electric generator 9, the second hydraulic pump motor 13 and the electric generator 9, engine 1, the second hydraulic pump motor 13 and the electric generator 9, and the electric generator 9, the first hydraulic pump motor 10 and the second hydraulic pump motor 13. The combined drive system involves multiple power sources driving simultaneously. The specific driving process is similar to the individual driving processes described above, combined into different forms of combined drive schemes. This combined drive scheme can stably adjust the economical operation of engine 1 over a long period, achieving energy saving and emission reduction effects.

[0073] This section provides a detailed analysis of the combined drive process of the electric generator 9, the first hydraulic pump motor 10, and the second hydraulic pump motor 13. The vehicle controller 20 monitors the SOC values ​​of the hydraulic accumulator 19 and the battery 11. After monitoring that the SOC value of the hydraulic accumulator 19 is in a state where it can release energy and the SOC value of the battery 11 is in a state where it can discharge energy, the vehicle controller 20 collects and processes the accelerator pedal opening signal. When it determines that the regenerative driving force meets the driving force required by the vehicle, it performs combined drive. The vehicle controller 20 controls the engagement of the fourth clutch 23, the third torque coupler 22 is connected to the transmission system, the vehicle controller 20 controls the engagement of the third clutch 12, the first torque coupler 2 is connected to the transmission system, the battery 11 discharges to the electric generator 9 to operate in motor mode, the motor torque drives the first hydraulic pump motor 10 to operate in pump mode through the third torque coupler 22, the hydraulic pump draws oil from the hydraulic oil tank 14 and outputs hydraulic oil to the second hydraulic pump motor 13 to operate in motor mode, the hydraulic motor torque drives the drive wheel 7 to rotate through the third clutch 12, the first torque coupler 2, the second torque coupler 4, the gearbox 5, and the drive axle 6, and the vehicle moves. In the process of the electric generator 9-first hydraulic pump motor 10-second hydraulic pump motor 13 joint drive, the electric-hydraulic conversion is actually performed by the first hydraulic pump motor 10 to output strong power, the engine 1 does not work, and the vehicle achieves energy saving and emission reduction effect.

[0074] In one possible embodiment of the present invention, a first relief valve 15 is further included, wherein a first interface of the first relief valve 15 is connected to the hydraulic oil tank 14, and a second interface of the first relief valve 15 is connected to the second hydraulic pump motor 13.

[0075] Specifically, in this embodiment, the first overflow valve 15 serves as an overload protection for the first auxiliary power component and can be used as a safety valve.

[0076] In one possible embodiment of the present invention, a second relief valve 18 is further included, wherein a first port of the second relief valve 18 is connected to the hydraulic oil tank, and a second port of the second relief valve 18 is connected to the hydraulic accumulator 19.

[0077] Specifically, in this embodiment, the second relief valve 18 controls the maximum working pressure of the hydraulic accumulator 19 through the relief pressure, and can be used as a relief valve.

[0078] In summary, the optimal energy recovery scheme for the braking condition of the hybrid hydraulic-electric-hydraulic system of the aforementioned mobile construction machinery is a hydraulic-electric composite energy recovery, in which hydraulic energy recovery and electrical energy recovery are carried out simultaneously. The specific process is as follows: because the hydraulic accumulator 19 has a high power density, it is used first when the vehicle starts. Therefore, during the braking energy recovery process, when hydraulic energy recovery and electrical energy recovery are carried out simultaneously, hydraulic energy recovery is prioritized. Thus, the torque of the drive wheel 7 drives the first hydraulic pump motor 10 to operate in pump mode via the fourth clutch 23, drawing oil from the hydraulic oil tank 14 and outputting hydraulic oil into the hydraulic accumulator 19 through the one-way valve 16, thereby accelerating the charging process of the hydraulic accumulator 19. After the hydraulic accumulator 19 is fully charged, the vehicle controller 20 controls the first hydraulic pump motor 10 to operate in motor mode, while the second hydraulic pump motor 13 continues to output hydraulic oil to the first hydraulic pump motor 10 in pump mode. The torque of the hydraulic motor drives the electric generator 9 to operate in generator mode via the fourth clutch 23 and the third torque coupler 22, accelerating the charging process of the battery 11. Therefore, in the optimal hydraulic-electric composite energy recovery scheme, the first hydraulic pump motor 10 operates in both pump and motor modes, accelerating the charging process of the hydraulic accumulator 19 and the battery 11, improving energy recovery efficiency, and thus recovering braking energy over a wide range and efficiently. The optimal power solution for the hybrid hydraulic-electric-hydraulic system of the aforementioned mobile construction machinery is to rationally select the drive mode based on the vehicle's required drive torque. When the regenerative drive force meets the drive requirements, the second hydraulic pump motor 13 can be driven alone, the electric generator 9 can be driven alone, or the electric generator 9, the first hydraulic pump motor 10, and the second hydraulic pump motor 13 can be driven together. When the regenerative drive force does not meet the drive requirements, the engine 1 and the second hydraulic pump motor 13 can be driven together, or the engine 1 and the electric generator 9 can be driven together, or the second hydraulic pump motor 13 and the electric generator 9 can be driven together. Therefore, the use of the engine 1 is reduced, or the engine 1 is stably adjusted to operate at its economic operating point for a long time, greatly improving the fuel economy of the entire vehicle and achieving significant energy saving and emission reduction results.

[0079] In short, the hybrid electric-hydraulic system of the mobile construction machinery can efficiently recover braking energy over a wide range during braking by adopting a reasonable energy recovery strategy. During driving, it can reduce the use of engine 1 or stably adjust engine 1 to operate at the economic operating point for a long time by adopting a reasonable driving strategy, which greatly improves the fuel economy of the whole vehicle and achieves significant energy saving and emission reduction results.

[0080] A second embodiment of the present invention provides a hybrid electric vehicle, including a mechanical body and a hybrid electric-hydraulic system for mobile construction machinery as described above, wherein the hybrid electric vehicle system for mobile construction machinery is configured on the mechanical body.

[0081] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions that fall within the scope of the present invention are within the scope of protection of the present invention.

Claims

1. A hybrid power system for mobile construction machinery, characterized in that: It includes a vehicle controller, a power coupling assembly, a main power assembly, a first auxiliary power assembly, a second auxiliary power assembly, a second clutch, a third clutch, and a fourth clutch; The output shaft of the main power component is connected to the input shaft of the power coupling component. The first auxiliary power component is connected to the input shaft of the power coupling component via the third clutch. The second auxiliary power component is connected to the input shaft of the power coupling component via the second clutch. The first auxiliary power component is connected to the second auxiliary power component via a pipeline through the four-clutch. The output terminal of the vehicle controller is electrically connected to the control terminals of the main power component, the first auxiliary power component, and the second auxiliary power component. The input terminal of the vehicle controller is used to electrically connect to the pedals and sensors of the traveling construction machinery. The power coupling assembly includes a first torque coupler, a second torque coupler, a gearbox, a drive axle, and drive wheels; Wherein, the output shaft of the main power component is connected to the input shaft of the second torque coupler, the first output shaft of the second torque coupler is connected to the input shaft of the gearbox, the second output shaft of the second torque coupler is connected to the input shaft of the first torque coupler, the first output shaft of the first torque coupler is connected to the input shaft of the first auxiliary power and the input shaft of the second auxiliary power component, the output shaft of the gearbox is connected to the drive axle, and the drive axle is connected to the drive wheel; The first auxiliary power assembly includes a second hydraulic pump motor, a first hydraulic pump motor, a hydraulic oil tank, a check valve, a two-position two-way solenoid directional valve, and a hydraulic accumulator; The first output shaft of the first torque coupler is connected to the second auxiliary power component, the second output shaft of the first torque coupler is connected to the second hydraulic pump motor through the third clutch, the first hydraulic pump motor is connected to the second auxiliary power component through the fourth clutch, the first hydraulic pump motor and the second hydraulic pump motor are connected in parallel, the low-pressure oil circuit of the second hydraulic pump motor is connected to the hydraulic oil tank, the high-pressure oil circuit of the second hydraulic pump motor is connected to the hydraulic accumulator through the two-position two-way solenoid directional valve and the one-way valve, and the output terminal of the vehicle controller is electrically connected to the control terminal of the third clutch, the control terminal of the first hydraulic pump motor, the control terminal of the second hydraulic pump motor, the control terminal of the two-position two-way solenoid directional valve, and the control terminal of the fourth clutch. The second auxiliary power assembly includes an electric generator, a third torque coupler, and a battery. The first output shaft of the first torque coupler is connected to the third torque coupler via the second clutch. The first output shaft of the third torque coupler is connected to the electric generator. The second output shaft of the third torque coupler is connected to the first hydraulic pump motor via the fourth clutch. The electric generator is electrically connected to the battery. The output terminal of the vehicle controller is electrically connected to the control terminal of the second clutch. The vehicle controller is configured to perform the following steps by executing a computer program stored internally: When the system is detected to be in a braking state, the SOC value of the hydraulic accumulator and the SOC value of the battery of the mobile construction machinery are acquired in real time, and the SOC values ​​of the hydraulic accumulator and the battery are compared with the corresponding preset values ​​to generate comparison results. When it is determined from the comparison result that only the hydraulic accumulator is in a recyclable state, the first auxiliary power component is controlled to convert the braking energy generated by the power coupling component into hydraulic energy and store it. When it is determined from the comparison results that only the battery is in a recyclable state, the first auxiliary power component and the second auxiliary power component are controlled to convert the braking energy generated by the power coupling component into electrical energy and store it. When it is determined from the comparison results that both the hydraulic accumulator and the battery are in a recyclable state, the first auxiliary power component is first controlled to convert the braking energy generated by the power coupling component into hydraulic energy and store it. When the SOC value of the hydraulic accumulator is detected that the energy recovery of the hydraulic accumulator is complete, the first auxiliary power component and the second auxiliary power component are controlled to convert the braking energy generated by the power coupling component into electrical energy and store it.

2. The hybrid hydraulic-electric-hydraulic system for mobile engineering machinery according to claim 1, characterized in that, Also includes: When the system is detected to be in driving mode, the SOC value of the hydraulic accumulator and the SOC value of the battery of the mobile construction machinery are acquired in real time, and the SOC values ​​of the hydraulic accumulator and the battery are compared with the corresponding preset values ​​to generate comparison results. When it is determined from the comparison result that only the hydraulic accumulator is in the energy release state, the first auxiliary power component is controlled to drive the power coupling component to rotate. When it is determined from the comparison result that only the battery is in a dischargeable state, the second auxiliary power component is controlled to drive the power coupling component to rotate. When it is determined from the comparison results that the hydraulic accumulator is not in a state where it can release energy and the battery is not in a state where it can discharge energy, the active power component is controlled to drive the power coupling component to rotate.

3. The hybrid hydraulic-electric-hydraulic system for mobile engineering machinery according to claim 1, characterized in that, It also includes a braking device configured on the drive wheel, and the output terminal of the vehicle controller is electrically connected to the control terminal of the braking device.

4. The hybrid hydraulic-electric-hydraulic system for mobile engineering machinery according to claim 1, characterized in that, The powertrain includes an engine and a first clutch. The output shaft of the engine is connected to the input shaft of the first torque coupler via the first clutch. The output terminal of the vehicle controller is electrically connected to the control terminal of the first clutch.

5. The hybrid hydraulic-electric-hydraulic system for mobile engineering machinery according to claim 1, characterized in that, It also includes a first relief valve, the first port of which is connected to the hydraulic oil tank, and the second port of which is connected to the second hydraulic pump motor.

6. The hybrid hydraulic-electric-hydraulic system for mobile engineering machinery according to claim 1, characterized in that, It also includes a second relief valve, the first port of which is connected to the hydraulic oil tank, and the second port of which is connected to the hydraulic accumulator.

7. A hybrid electric vehicle, characterized in that, The system includes a mechanical body and a hybrid hydraulic-electric-hydraulic system for mobile construction machinery as described in any one of claims 1 to 6, wherein the hybrid hydraulic-electric-hydraulic system for mobile construction machinery is disposed on the mechanical body.

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