Hybrid vehicle and its traveling construction machine hybrid system

Abstract

The application provides an oil hybrid vehicle and an oil hybrid power system of a walking engineering machine, and the system has an electrical type based on a motor generator, a hydraulic type based on a pump motor and a composite type based on a motor generator-pump motor for recovering walking braking energy, so that the braking energy can be recovered in a wide range and with high efficiency, and the braking energy recovery efficiency is improved; in a system driving condition, power is provided in multiple forms such as engine single driving, pump motor single driving, motor generator-pump motor single driving, engine-pump motor combined driving and engine-motor generator-pump motor combined driving, so that the use of the engine is reduced through multiple single driving modes, the engine can be stably operated in an economic condition for a long time through multiple combined driving modes, the fuel economy of the whole vehicle is 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 engineering machinery, specifically to hydraulic hybrid vehicles and their hydraulic hybrid power systems for mobile engineering 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 hydraulic hybrid vehicle and a hydraulic hybrid system for mobile engineering machinery, which can effectively solve the problem that the hydraulic hybrid system in the prior art has low energy density of hydraulic accumulator and limited space due to the limited installation space, resulting in limited energy storage space and thus low energy recovery efficiency during driving and braking.

[0006] This invention provides a hydraulic hybrid power system for mobile construction machinery, including a vehicle controller, a power coupling component, a main power component, a second clutch, a first auxiliary power component, and a second auxiliary power component;

[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 through the second clutch. The first auxiliary power component and the second auxiliary power component are connected in parallel. The output terminal of the vehicle controller 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 is used to electrically connect to the pedals of the traveling construction machinery and the 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 an energy recovery 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 an energy recovery 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 an energy recovery 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 energy recovery of the hydraulic accumulator is completed according to the SOC value of the hydraulic accumulator, 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 the energy release state, 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 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 torque coupler, the first output shaft of the torque coupler is connected to the input shaft of the gearbox, the second output shaft of the torque coupler is connected to the input shaft of the first 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 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 second clutch, a second hydraulic pump motor, a hydraulic oil tank, a one-way valve, a two-position two-way solenoid directional valve, and a hydraulic accumulator.

[0023] The second output shaft of the torque coupler is connected to the second hydraulic pump motor via the second clutch. 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 check valve. The second hydraulic pump motor is connected in parallel with the second auxiliary power component. The output terminal of the vehicle controller is electrically connected to the control terminal of the second clutch, the control terminal of the second hydraulic pump motor, and the control terminal of the two-position two-way solenoid directional valve.

[0024] Preferably, the second auxiliary power component includes a first hydraulic pump motor, an electric generator, and a battery. The first hydraulic pump motor is coaxially connected to the electric generator, the electric generator is electrically connected to the battery, and the output terminal of the vehicle controller is electrically connected to the control terminal of the first hydraulic pump motor.

[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 vehicle body and a hybrid electric vehicle system for mobile construction machinery as described above, wherein the hybrid electric vehicle system for mobile construction machinery is disposed on the vehicle body.

[0028] In summary, the hydraulic hybrid vehicle and its mobile engineering machinery hydraulic hybrid system provided in this embodiment can efficiently recover braking energy over a wide range during braking conditions through a reasonable energy recovery strategy; during driving conditions, it can reduce engine usage or stably adjust the engine to operate at the economic operating point for a long time through a reasonable driving strategy, greatly improving the fuel economy of the vehicle and achieving significant energy saving and emission reduction results; thus solving the problem of low energy recovery efficiency of existing hydraulic hybrid systems due to the low energy density of hydraulic accumulators and the limited installation space, resulting in limited energy storage space. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the hydraulic hybrid power 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 hydraulic hybrid power system for mobile construction machinery, including a vehicle controller 19, a power coupling component, a main power component, a second clutch 8, a first auxiliary power component, and a second auxiliary power component;

[0033] The output shaft of the active 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 second clutch 8. The first auxiliary power component and the second auxiliary power component are connected in parallel. The output terminal of the vehicle controller 19 is electrically connected to the control terminal of the active 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 19 is used to electrically connect to the pedals of the traveling construction machinery and the sensors of the traveling construction machinery.

[0034] The vehicle controller 19 is configured to perform the following steps by executing a computer program stored internally thereon:

[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 an energy recovery 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 an energy recovery 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 an energy recovery 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 energy recovery of the hydraulic accumulator is completed according to the SOC value of the hydraulic accumulator, 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 19 controls the component states of the hydraulic hybrid power system of the mobile construction machinery to ensure its smooth operation. The vehicle controller 19 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 signal, clutch pedal opening signal, accelerator pedal opening signal, brake pedal opening signal, hydraulic system pressure sensor pressure feedback signal, hydraulic accumulator SOC signal, and battery SOC signal. 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 19 executes a predetermined control strategy, sending control signals to the motor controller, engine controller, two-position two-way solenoid directional valve, second clutch, first and second hydraulic pump motors, etc., thereby controlling the operating status of each component, ensuring the smooth operation of the hydraulic hybrid power system, and realizing various driving and braking working modes.

[0041] In this embodiment, the hydraulic hybrid power system for mobile construction machinery structurally includes a first active 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 also includes a power-type energy storage unit (hydraulic accumulator) and an energy-type energy storage unit (battery). When the hydraulic hybrid power system is in braking condition, 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 combined method based on the electric generator and hydraulic pump motor. 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, capable of large-scale, efficient braking energy recovery, and can stably adjust the engine's economical operation for extended periods, 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 the energy release state, 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 hydraulic hybrid power 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-hydraulic pump motor-only drive, engine-hydraulic pump motor combined drive, and engine-electric generator-hydraulic pump motor combined drive. By reducing engine usage through multiple individual drive methods and achieving stable engine operation in economic conditions for a long time through multiple combined drive methods, the fuel economy of the whole 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 torque coupler 3, a gearbox 4, a drive axle 5, and a drive wheel 7;

[0050] The output shaft of the main power component is connected to the input shaft of the torque coupler 3, the first output shaft of the torque coupler 3 is connected to the input shaft of the gearbox 4, the second output shaft of the torque coupler 3 is connected to the input shaft of the first auxiliary power component, the output shaft of the gearbox 4 is connected to the drive axle 5, and the drive axle 5 is connected to the drive wheel 7.

[0051] Specifically, in this embodiment, the torque coupler 3 can be a gear-type torque coupler, which can be simply understood as a clutch, although its principle and structure are more complex than a regular clutch. The gearbox 4, the drive axle 5, and the drive wheel 7 can be considered as a transmission system. A transmission system refers to a device that transmits power between a power source such as an engine and the drive wheels of a 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 torque couplers can also be used. This is not specifically limited 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 6 is also included, which is disposed on the drive wheel 7, and the output terminal of the vehicle controller 19 is electrically connected to the control terminal of the braking device 6.

[0053] Specifically, in this embodiment, the braking device 6 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 2, wherein the output shaft of the engine 1 is connected to the input shaft of the torque coupler 3 through the first clutch 2, and the output terminal of the vehicle controller 19 is electrically connected to the control terminal of the first clutch 2.

[0055] In one possible embodiment of the present invention, the first auxiliary power component includes a second clutch 8, a second hydraulic pump motor 9, a hydraulic oil tank 10, a one-way valve 12, a two-position two-way solenoid directional valve 13, and a hydraulic accumulator 15.

[0056] The second output shaft of the torque coupler 3 is connected to the second hydraulic pump motor 9 via the second clutch 8. The low-pressure oil circuit of the second hydraulic pump motor 9 is connected to the hydraulic oil tank 10. The high-pressure oil circuit of the second hydraulic pump motor 9 is connected to the hydraulic accumulator 15 via the two-position two-way solenoid directional valve 13 and the one-way valve 12. The second hydraulic pump motor 9 is connected in parallel with the second auxiliary power component. The output terminal of the vehicle controller 19 is electrically connected to the control terminal of the second clutch 8, the control terminal of the second hydraulic pump motor 9, and the control terminal of the two-position two-way solenoid directional valve 13.

[0057] In one possible embodiment of the present invention, the second auxiliary power component includes a first hydraulic pump motor 16, an electric generator 17, and a battery 18. The first hydraulic pump motor 16 is coaxially connected to the electric generator 17, the electric generator 17 is electrically connected to the battery 18, and the output terminal of the vehicle controller 19 is electrically connected to the control terminal of the first hydraulic pump motor 16.

[0058] Specifically, in this embodiment, the first hydraulic pump motor 16 and the second hydraulic pump motor 9 can be variable displacement hydraulic pump motors. When the second hydraulic pump motor 9 is in pump mode, the hydraulic oil output by the hydraulic pump flows into the hydraulic accumulator 15 through the one-way valve 12, which is the charging process of the hydraulic accumulator 15; the hydraulic oil output by the hydraulic pump can also directly supply oil to the first hydraulic pump motor 16, at which time the first hydraulic pump motor 16 is in motor mode. When the second hydraulic pump motor 9 is in motor mode, the two-position two-way solenoid directional valve 13 opens, and the hydraulic accumulator 15 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 15.

[0059] When the first hydraulic pump motor 16 is in pump mode, the hydraulic oil output by the hydraulic pump flows into the hydraulic accumulator 15 through the one-way valve 12; the hydraulic oil output by the hydraulic pump can also directly supply oil to the second hydraulic pump motor 9, at which time the second hydraulic pump motor 9 operates in motor mode. When the first hydraulic pump motor 16 is in motor mode, it directly drives the electric generator 17 to operate in generator mode, and the generator charges the battery 18. When the electric generator 17 is in electric motor mode, it directly drives the first hydraulic pump motor 16 to operate in pump mode, which is the discharge process of the battery 18. It should be noted that in other embodiments, other types of first and second hydraulic pump motors can also be used, which are not specifically limited here, but these solutions are all within the protection scope of this invention.

[0060] In this embodiment, when the hydraulic hybrid power system of the mobile construction machinery brakes, the engine 1 stops working, the first clutch 2 disengages, the gearbox 4 is in any gear, the second clutch 8 engages, and the second hydraulic pump motor 9 is connected to the transmission system through the torque coupler 3, starting to operate in pump mode. The first hydraulic pump motor 16 operates in motor mode, directly driving the electric generator 17 to operate in generator mode. The hydraulic accumulator 15 is charged and the battery 18 is charged, realizing the recovery of vehicle braking energy. When the hydraulic hybrid power system of the mobile construction machinery is driven, the engine 1 starts working, the first clutch 2 engages, and the torque coupler 3 is connected to the transmission system. The second clutch 8 engages, the second hydraulic pump motor 9 is connected to the transmission system through the torque coupler 3, the gearbox 4 is in a certain gear, the electric generator 17 operates in motor mode, driving the first hydraulic pump motor 16 to operate in pump mode, the second hydraulic pump motor 9 operates in motor mode, the hydraulic accumulator 15 releases energy, and the battery 18 discharges, realizing the release of the recovered vehicle braking energy.

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

[0062] When the hydraulic hybrid power system of the mobile construction machinery brakes, the braking force is provided by mechanical friction braking and hydraulic regenerative braking. When hydraulic regenerative braking participates in the braking process, it can recover energy from vehicle movement. During vehicle braking, regenerative braking takes priority for energy recovery, with mechanical friction braking assisting. In emergency braking situations, mechanical friction braking is used directly, and regenerative braking does not participate.

[0063] First, the hydraulic accumulator recovers energy independently. The vehicle controller 19 monitors the SOC value of the hydraulic accumulator 15. When the SOC value is in a recyclable state, hydraulic energy recovery is performed. The vehicle controller 19 collects and processes the brake pedal opening signal to determine the required braking torque of the vehicle and allocates it appropriately. The vehicle controller 19 controls the second clutch 8 to engage, and the torque coupler 3 is connected to the transmission system. The torque of the drive wheel 7 drives the second hydraulic pump motor 9 to operate in pump mode via the drive axle 5, the gearbox 4, the torque coupler 3, and the second clutch 8. The hydraulic pump draws oil from the hydraulic oil tank 10 and outputs hydraulic oil into the hydraulic accumulator 15 through the one-way valve 12, 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 15, completing the braking energy recovery process. The vehicle controller 19 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 to ensure braking safety.

[0064] Secondly, the battery recovers energy independently. The vehicle controller 19 monitors the SOC value of the battery 18. When the SOC value is in a recyclable state, electrical energy recovery is performed. The vehicle controller 19 collects and processes the brake pedal opening signal to determine the required braking torque of the vehicle and allocates it appropriately. The vehicle controller 19 controls the second clutch to engage, and the torque coupler 3 is connected to the transmission system. The torque of the drive wheel 7 drives the second hydraulic pump motor 9 to operate in pump mode via the drive axle 5, the gearbox 4, the torque coupler 3, and the second clutch 8. The hydraulic pump draws oil from the hydraulic oil tank 10 and outputs hydraulic oil to supply the first hydraulic pump motor 16 to operate in motor mode. The hydraulic motor drives the electric generator 17 to operate in generator mode, thereby charging the battery 18. The hydraulic pump generates regenerative braking torque to decelerate the drive wheel 7. In this way, the kinetic energy of the vehicle is converted into electrical energy in the battery 18, completing the braking energy recovery process.

[0065] Finally, a combined hydraulic accumulator-battery energy recovery process is implemented. The vehicle controller 19 monitors the SOC values ​​of the hydraulic accumulator 15 and the battery 18. When the SOC value is within a recoverable range, a combined hydraulic-electrical energy recovery process is performed. The vehicle controller 19 also collects and processes the brake pedal opening signal to determine the required braking torque for the entire vehicle and allocates it appropriately. The vehicle controller 19 controls the second clutch 8 to engage, the torque coupler 3 is connected to the transmission system, and the vehicle controller 19 controls the displacement of the first hydraulic pump motor 16 and the second hydraulic pump motor 9. The torque of the drive wheel 7 drives the second hydraulic pump motor 9 to operate in pump mode via the drive axle 5, the gearbox 4, the torque coupler 3, and the second clutch 8. The hydraulic pump draws oil from the hydraulic oil tank 10 and outputs hydraulic oil, which flows into the hydraulic accumulator through the one-way valve 12 for hydraulic energy recovery. The hydraulic pump draws oil from the hydraulic oil tank and outputs hydraulic oil to supply the first hydraulic pump motor 16 for motor mode operation. The hydraulic motor drives the electric generator 17 to operate in generator mode, thereby charging the battery 18 for electrical energy recovery. Hydraulic energy recovery and electrical energy recovery are carried out simultaneously.

[0066] When the hydraulic hybrid power 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 9, and the electric generator 17. When the second hydraulic pump motor 9 and the electric generator 17 participate in the driving process, the energy recovered by the system can be released. During the system driving process, the auxiliary power source is given priority to provide power, reducing the use of the engine 1 or avoiding the engine 1 from working in the inefficient range, which is conducive to energy saving and emission reduction.

[0067] First, the engine drives alone. When the engine 1 is driven alone, the first clutch 2 is engaged by controlling the clutch pedal. The torque of the engine 1 drives the drive wheel 7 to rotate through the first clutch 2, the torque coupler 3, the gearbox 4, and the drive axle 5, thus moving the vehicle. The process of the engine 1 driving alone is the same as that of a conventional vehicle, and there is no energy saving or emission reduction effect. However, during the process of the engine 1 driving alone, the excess power of the engine 1 can be recovered by the hydraulic regeneration system and stored in the hydraulic accumulator 15, thereby improving energy utilization efficiency.

[0068] Secondly, the second hydraulic pump motor is driven independently. The vehicle controller 19 monitors the SOC value of the hydraulic accumulator 15. After monitoring that the SOC value is in a state where energy can be released, the vehicle controller 19 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 9 is driven independently. The vehicle controller 19 controls the second clutch 8 to engage, the torque coupler 3 is connected to the transmission system, and the vehicle controller 19 controls the two-position two-way solenoid valve 13 to open. The hydraulic oil in the hydraulic accumulator 15 is supplied to the second hydraulic pump motor 9 through the two-position two-way solenoid valve 13. During motor operation, the torque of the hydraulic motor drives the drive wheel 7 to rotate through the second clutch 8, the torque coupler 3, the gearbox 4, and the drive axle 5, thus moving the vehicle. During the independent driving of the second hydraulic pump motor 9, the engine 1 does not work, and the vehicle achieves energy saving and emission reduction effects.

[0069] Secondly, the electric generator operates independently. The vehicle controller 19 monitors the SOC value of the battery 18. After detecting that the SOC value is in a dischargeable state, the vehicle controller 19 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 17 operates independently. The vehicle controller 19 controls the second clutch 8 to engage, and the torque coupler 3 is connected to the transmission system. The battery 18 discharges to the electric generator 17, which operates under motor conditions. The motor torque drives the drive wheel 7 to rotate through the first hydraulic pump motor 16, the second hydraulic pump motor 9, the second clutch 8, the torque coupler 3, the gearbox 4, and the drive axle 5, thus moving the vehicle. During the independent operation of the electric generator 17, the first hydraulic pump motor 16 and the second hydraulic pump motor 9 act as electro-hydraulic-mechanical energy conversion units, while the engine 1 does not work, achieving energy saving and emission reduction effects.

[0070] Finally, a combined drive system is implemented, comprising the combined drive of engine 1 and the second hydraulic pump motor 9, the combined drive of engine 1, the electric generator 17, the first hydraulic pump motor 16, and the second hydraulic pump motor 9, and the combined drive of electric generator 17, the first hydraulic pump motor 16, and the second hydraulic pump motor 9. 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.

[0071] This section provides a detailed analysis of the combined drive process of the electric generator 17, the first hydraulic pump motor 16, and the second hydraulic pump motor 9. The vehicle controller 19 monitors the SOC values ​​of the hydraulic accumulator 15 and the battery 18. After monitoring that the SOC value of the hydraulic accumulator 15 is in a state where it can release energy and the SOC value of the battery 18 is in a state where it can discharge energy, the vehicle controller 19 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 19 engages the second clutch 8, and the torque coupler 3 connects to the transmission system. Hydraulic oil in the hydraulic accumulator 15 is supplied to the second hydraulic pump motor 9 via the two-position two-way solenoid valve 13, operating in motor mode. Simultaneously, the battery 18 discharges to the electric generator 17, operating in electric motor mode. The electric generator drives the first hydraulic pump motor 16, operating in pump mode. The hydraulic pump draws oil from the hydraulic oil tank 10 and outputs hydraulic oil to the second hydraulic pump motor 9, operating in motor mode. Finally, the torque of the hydraulic motor, via the second clutch 8, the torque coupler 3, the gearbox 4, and the drive axle 5, drives the drive wheel 7 to rotate, causing the vehicle to move. During the combined drive process of the electric generator 17, the first hydraulic pump motor 16, and the second hydraulic pump motor 9, the engine 1 does not operate, achieving energy saving and emission reduction.

[0072] In one possible embodiment of the present invention, a first relief valve 11 is further included, wherein a first interface of the first relief valve 11 is connected to the hydraulic oil tank 10, and a second interface of the first relief valve 11 is connected to the second hydraulic pump motor 9.

[0073] Specifically, in this embodiment, the first overflow valve 11 serves as an overload protection for the first auxiliary power component and can be used as a safety valve.

[0074] In one possible embodiment of the present invention, a second relief valve 14 is further included, the first interface of the second relief valve 14 being connected to the hydraulic oil tank 10, and the second interface of the first relief valve 11 being connected to the hydraulic accumulator 15.

[0075] Specifically, in this embodiment, the second relief valve 14 controls the maximum working pressure of the hydraulic accumulator 15 through the relief pressure, and can be used as a relief valve.

[0076] In summary, the optimal energy recovery scheme for the hydraulic hybrid power system of the aforementioned mobile construction machinery during braking is a hydraulic-electric composite energy recovery, with hydraulic and electrical energy recovery occurring sequentially. Specifically, because the hydraulic accumulator 15 has a high power density and is prioritized during vehicle start-up, hydraulic energy recovery takes precedence during braking energy recovery, with electrical recovery assisting. Therefore, the torque of the drive wheel 7 drives the second hydraulic pump motor 9 to operate in pump mode via the drive axle 5, the gearbox 4, the torque coupler 3, and the second clutch 8. The hydraulic pump draws oil from the hydraulic oil tank 10 and outputs hydraulic oil, which flows through the one-way valve 12 into the hydraulic accumulator 15 for hydraulic energy recovery. After the hydraulic accumulator 15 is fully charged, the hydraulic pump draws oil from the hydraulic oil tank 10 and outputs hydraulic oil to supply the first hydraulic pump motor 16 for motor operation. The hydraulic motor drives the electric generator 17 for generator operation, thereby charging the battery 18 and performing electrical energy recovery. Therefore, in the optimal hydraulic-electric composite energy recovery scheme, braking energy can be recovered over a wide range and efficiently, improving energy recovery efficiency. The optimal power solution for the hydraulic hybrid power system of the aforementioned mobile construction machinery is to rationally select the drive mode based on the vehicle's required drive torque. When the regenerated drive force meets the drive requirements, the second hydraulic pump motor 9 can be driven alone, the electric generator 17 can be driven alone, or the electric generator 17-first hydraulic pump motor 16-second hydraulic pump motor 9 can be driven together. When the regenerated drive force does not meet the drive requirements, the engine 1-second hydraulic pump motor 9 can be driven together, or the engine 1-electric generator 17-first hydraulic pump motor 16-second hydraulic pump motor 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, which greatly improves the fuel economy of the entire vehicle and achieves significant energy saving and emission reduction results.

[0077] In simple terms, the hydraulic hybrid power system of the mobile construction machinery can recover braking energy efficiently over a wide range during braking conditions through a reasonable energy recovery strategy; during driving conditions, it can reduce the use of engine 1 or stably adjust the engine to operate at the economic operating point for a long time through a reasonable driving strategy, which greatly improves the fuel economy of the whole vehicle and achieves significant energy saving and emission reduction results.

[0078] The second embodiment of the present invention provides a hybrid electric vehicle, including a vehicle body and a hybrid electric vehicle system for mobile construction machinery as described above, wherein the hybrid electric vehicle system for mobile construction machinery is disposed on the vehicle body.

[0079] 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 hydraulic hybrid power system for mobile construction machinery, characterized in that, This includes the vehicle controller, power coupling assembly, main power assembly, second clutch, first auxiliary power assembly, and second auxiliary power assembly; 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 second clutch. The first auxiliary power component and the second auxiliary power component are connected in parallel. The output terminal of the vehicle controller 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 is used to electrically connect to the pedals of the traveling construction machinery and the sensors of the traveling construction machinery. The power coupling assembly includes a 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 torque coupler, the first output shaft of the torque coupler is connected to the input shaft of the gearbox, the second output shaft of the torque coupler is connected to the input shaft of the first 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 hydraulic oil tank, a check valve, a two-position two-way solenoid directional valve, and a hydraulic accumulator; The torque coupler's second output shaft is connected to the second hydraulic pump motor via the second clutch. 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 check valve. The second hydraulic pump motor is connected in parallel with the second auxiliary power assembly. The output terminal of the vehicle controller is electrically connected to the control terminal of the second clutch, the control terminal of the second hydraulic pump motor, and the control terminal of the two-position two-way solenoid directional valve. The second auxiliary power component includes a first hydraulic pump motor, an electric generator, and a battery. The first hydraulic pump motor is coaxially connected to the electric generator, the electric generator is electrically connected to the battery, and the output terminal of the vehicle controller is electrically connected to the control terminal of the first hydraulic pump motor. 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 an energy recovery 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 result that only the battery is in an energy recovery 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 an energy recovery 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 energy recovery of the hydraulic accumulator is completed according to the SOC value of the hydraulic accumulator, 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 hydraulic hybrid power 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 hydraulic hybrid power 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 hydraulic hybrid power 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 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 hydraulic hybrid power 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 hydraulic hybrid power 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 vehicle body and a mobile engineering machinery hydraulic hybrid power system as described in any one of claims 1 to 6, wherein the mobile engineering machinery hydraulic hybrid power system is configured on the vehicle body.

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