Multifunctional hydraulic hybrid system test bench

Abstract

This invention belongs to the field of hydraulic hybrid power technology and proposes a multifunctional hydraulic hybrid power system experimental platform. By setting up an electromagnetic clutch group with linkage and interlocking control relationships, the series and parallel hydraulic hybrid power structures can be switched by controlling the engagement and disengagement of different clutches on the same experimental platform. Compared with existing technologies, this invention can complete experimental research on different configurations without changing the hardware system, improving the versatility and utilization of the experimental platform. This invention constructs a unified mechanical-hydraulic coupling testing system by arranging multi-dimensional sensors in the mechanical transmission unit and hydraulic system. It realizes the synchronous acquisition and comprehensive analysis of mechanical and hydraulic parameters, which can comprehensively reflect the energy transfer process and working mechanism of the system, thereby solving the problem of scattered and incomplete parameter monitoring and improving the integrity and reliability of experimental data.

Description

Technical Field

[0001] This invention relates to the field of hydraulic hybrid power technology, and in particular to a multifunctional hydraulic hybrid power system test bench. Background Technology

[0002] With increasingly stringent requirements for energy conservation and emission reduction, hydraulic hybrid power systems are gradually becoming an important development direction for power systems in engineering vehicles and special vehicles due to their advantages such as high power density, high energy recovery efficiency, and fast response speed. To reduce vehicle testing costs and improve system development efficiency, it is typically necessary to construct an experimental platform to conduct performance testing and control strategy verification of the hydraulic hybrid power system.

[0003] Most existing hydraulic hybrid power test benches are designed for a single structural form (such as series or parallel), lacking the ability to switch between multiple configurations. At the same time, during system testing, only local parameter monitoring can often be achieved, making it difficult to conduct unified and coordinated analysis of the mechanical transmission part (speed, torque) and the hydraulic transmission part (pressure, flow). In addition, existing test benches usually cannot simultaneously achieve the following functions: (1) engine fuel consumption and emission testing under hybrid and single drive states; (2) simulation of multi-load coordinated control and energy recovery process under constant pressure system; (3) simulation and evaluation of vehicle friction braking characteristics.

[0004] In addition, in the existing technology, each subsystem (power source, hydraulic circuit, loading system and control system) is designed relatively independently and lacks a unified structural integration scheme, resulting in poor functional expandability of the test bench and limited coverage of working conditions.

[0005] Therefore, there is an urgent need for a multifunctional hydraulic hybrid power system test bench with high structural integration, capable of switching between series and parallel structures, and equipped with functions such as multi-parameter monitoring, energy recovery control, and braking simulation. Summary of the Invention

[0006] Therefore, one objective of this invention is to provide a multifunctional hydraulic hybrid power system test bench to solve the problems mentioned in the background art and overcome the shortcomings of the prior art.

[0007] To achieve the above objectives, the present invention provides a multifunctional hydraulic hybrid power system test bench, comprising: A power input unit, including an engine, is used to provide mechanical power output; The mechanical transmission unit connected to the power input unit includes a connecting coupling, a gearbox, and an electromagnetic clutch, used for power transmission and switching of transmission paths; The hydraulic system connected to the mechanical transmission unit includes a constant pressure variable pump, an accumulator group, at least one pair of secondary components, and a hydraulic control valve group, used for the conversion, storage, and recovery of mechanical energy and hydraulic energy; The loading unit connected to the hydraulic system includes a brake and a flywheel assembly, used to simulate external loads and inertial loads; The measuring unit connected to the mechanical transmission unit, the hydraulic system, and the loading unit includes a speed and torque sensor, a pressure sensor, and a flow sensor; in, The electromagnetic clutch in the mechanical transmission unit is configured to include at least a clutch assembly and a second clutch. The clutch assembly and the third clutch are connected by a linkage and interlock control relationship, such that: When the clutch group is engaged and the third clutch is disengaged, the output of the power input unit is transmitted in parallel with the hydraulic system through the mechanical transmission path, forming a parallel hydraulic hybrid power structure. When the third clutch is engaged and the clutch group is disengaged, the output of the power input unit is transmitted through the hydraulic system, forming a series hydraulic hybrid power structure. The hydraulic system is a constant pressure system. The constant pressure variable pump is used to maintain the system pressure stability. The secondary element converts mechanical energy into hydraulic energy under load conditions and stores it in the accumulator group. The accumulator group includes multiple accumulators of different volumes, which are selectively connected to the hydraulic system via control valves.

[0008] Preferably, the clutch assembly includes a first electromagnetic clutch and a third electromagnetic clutch, which are respectively disposed on the mechanical transmission path for synchronous engagement or disengagement.

[0009] Preferably, an electrical interlock or control logic interlock is provided between the clutch assembly and the second clutch, allowing only one power transmission path to be in operation at any given time.

[0010] Preferably, the hydraulic control valve group includes a second valve for switching the system operating mode. When the test bench is operating in a series hydraulic hybrid power structure, the second valve is opened to make the hydraulic system form a constant pressure network to simulate multi-load collaborative control conditions.

[0011] Preferably, the power input unit includes an engine, and the test bench also includes an emissions testing instrument, configured to switch between an engine-only drive mode and a hybrid drive mode, for testing the engine's fuel consumption and emissions performance under different drive modes.

[0012] Preferably, the constant pressure variable pump is a pressure-compensated variable pump, and the output pressure is maintained within a preset constant range.

[0013] Preferably, the secondary element operates in two modes: a pump mode and a motor mode. During loading, it absorbs mechanical energy and converts it into hydraulic energy, and during release, it converts the hydraulic energy back into mechanical energy for output.

[0014] Preferably, the accumulator group includes multiple accumulators arranged in parallel, and each accumulator is connected to the hydraulic system through an independent control valve.

[0015] Preferably, the flywheel assembly in the loading unit is used to simulate the inertial load of a vehicle, and the brake is used to simulate the friction braking of a vehicle, and different working conditions can be achieved by adjusting the braking force.

[0016] Preferably, the measuring unit is located at the node of the mechanical transmission path and the hydraulic system to simultaneously collect mechanical parameters and hydraulic parameters.

[0017] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: This invention, by setting up an electromagnetic clutch group with linkage and interlocking control relationships, enables the switching between series and parallel hydraulic hybrid power structures on the same experimental platform by controlling the engagement and disengagement of different clutches. Compared with existing technologies, this invention can complete experimental research on different configurations without changing the hardware system, improving the versatility and utilization of the experimental platform.

[0018] This invention constructs a unified mechanical-hydraulic coupled testing system by arranging multi-dimensional sensors in the mechanical transmission unit and hydraulic system. It achieves synchronous acquisition and comprehensive analysis of mechanical and hydraulic parameters, fully reflecting the energy transfer process and working mechanism of the system. This solves the problems of scattered and incomplete parameter monitoring, improving the completeness and reliability of experimental data.

[0019] This invention uses an engine as the power input unit and integrates emission testing instruments into the test bench. Furthermore, through a flexible transmission path design, it enables switching between hybrid drive mode and engine-only drive mode. This allows the test bench to not only test power transmission performance but also to be used to evaluate the engine's fuel economy and emission characteristics under different operating modes, providing stronger comprehensive testing and performance evaluation capabilities.

[0020] This invention employs a constant-pressure hydraulic system consisting of a constant-pressure variable pump, an accumulator group, and secondary components, along with corresponding control valve groups, to construct a loop capable of stabilizing system pressure. It can simulate multi-load coordinated control under constant-pressure networks and utilizes secondary components to convert mechanical energy into hydraulic energy stored in the accumulator under braking or loading conditions, achieving a systematic simulation of energy recovery and reuse processes. This provides an effective means for in-depth research on energy management strategies for hydraulic hybrid power systems.

[0021] This invention employs a loading unit consisting of a brake and a flywheel assembly. The brake directly simulates the friction braking process of a vehicle, while the flywheel assembly simulates the inertial load of the vehicle. Through the combination of these two components, the experimental platform can reproduce the dynamic response and load characteristics of a vehicle in actual operation, thereby solving the problems of insufficient load simulation capability and unrealistic operating condition simulation in existing experimental platforms, and improving the engineering reference value of the experimental results.

[0022] Furthermore, this invention achieves adjustable system energy storage capacity and characteristics by employing an energy storage group composed of multiple energy storage devices of different volumes and selectively connecting them to the system using control valves. This design allows researchers to easily study the impact of different energy storage scales and charging pressures on the system's energy recovery efficiency and dynamic performance, enhancing the flexibility and depth of research in scientific research and teaching.

[0023] This invention constructs a multi-layered safety protection and auxiliary system by setting an overflow valve as a safety valve, configuring an oil filter with alarm in the critical circuit, and setting an electromagnetic switch valve for emergency unloading. These measures effectively improve the safety and reliability of the test bench under long-term, complex operating conditions.

[0024] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the structure of the multifunctional hydraulic hybrid power system test bench according to an embodiment of the present invention.

[0026] The components include: 1. Accelerator pedal; 2. Brake pedal; 3. First angle sensor; 4. Second angle sensor; 5. Accumulator group; 6. First valve; 7. First pressure sensor; 8. First relief valve; 9. Second valve; 10. Engine; 11. First coupling; 12. First transfer case; 13. First electromagnetic clutch; 14. First flow sensor; 15. Automatic transmission; 16. Third electromagnetic clutch; 17. Second transfer case; 18. Second coupling; 19. Second flow sensor; 20. First flywheel assembly; 21. Third coupling; 22. First brake; 23. Third flow sensor; 24. Emission testing instrument; 25. Check valve; 26. Second electromagnetic clutch; 27. Constant pressure variable pump; 28. Gear position detector; 29. ​​Multi-plate electromagnetic... 30. Clutch; 31. Fourth Coupling; 32. First Secondary Component; 33. Secondary Component; 34. Fifth Coupling; 35. Second Flywheel Assembly; 36. Sixth Coupling; 37. Second Brake; 38. Displacement Sensor; 39. Secondary Component Variable Cylinder; 40. Secondary Pressure Sensor; 41. Third Pressure Sensor; 42. Third Valve; 43. Secondary Component Variable Control Assembly; 44. Fourth Valve; 45. First Oil Filter; 46. Fourth Flow Sensor; 47. Servo Valve; 48. Pre-pressurized Air Filter; 59. Oil Tank Thermometer; 50. Oil Tank Level Gauge; 51. Second Oil Filter; 52. Electric Motor; 53. Gear Pump; 54. Second Relief Valve; 55. Third Oil Filter; 56. Fourth Oil Filter; 57. Oil Tank. Detailed Implementation

[0027] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0028] like Figure 1 As shown, an embodiment of the present invention provides a multifunctional hydraulic hybrid power system test bench, comprising: A power input unit, including an engine, is used to provide mechanical power output; The mechanical transmission unit connected to the power input unit includes a connected coupling, a gearbox, and at least one set of electromagnetic clutches for power transmission and switching of transmission paths. The hydraulic system connected to the mechanical transmission unit includes a constant pressure variable pump, an accumulator group, at least one pair of secondary components, and a hydraulic control valve group, used for the conversion, storage, and recovery of mechanical energy and hydraulic energy; The loading unit connected to the hydraulic system includes a brake and a flywheel assembly, used to simulate external loads and inertial loads; The measuring unit connected to the mechanical transmission unit, the hydraulic system, and the loading unit includes a speed and torque sensor, a pressure sensor, and a flow sensor; in, The electromagnetic clutch in the mechanical transmission unit is configured to include at least a clutch assembly and a second clutch. The clutch assembly and the third clutch are connected by a linkage and interlock control relationship, such that: When the clutch group is engaged and the third clutch is disengaged, the output of the power input unit is transmitted in parallel with the hydraulic system through the mechanical transmission path, forming a parallel hydraulic hybrid power structure. When the third clutch is engaged and the clutch group is disengaged, the output of the power input unit is transmitted through the hydraulic system, forming a series hydraulic hybrid power structure. The hydraulic system is a constant pressure system. The constant pressure variable pump is used to maintain the system pressure stability. The secondary element converts mechanical energy into hydraulic energy under load conditions and stores it in the accumulator group. The accumulator group includes multiple accumulators of different volumes, which are selectively connected to the hydraulic system via control valves.

[0029] Furthermore, the clutch assembly includes a first electromagnetic clutch and a third electromagnetic clutch, which are respectively located at different positions on the mechanical transmission path for synchronous engagement or disengagement.

[0030] Furthermore, an electrical interlock or control logic interlock is provided between the clutch assembly and the second clutch to ensure that only one power transmission path is allowed to be in operation at any given time.

[0031] Furthermore, the hydraulic control valve group includes a second valve for switching the system operating mode. When the test bench is operating in a series hydraulic hybrid power structure, the hydraulic system forms a constant pressure network by opening the second valve to simulate multi-load collaborative control conditions.

[0032] Furthermore, the power input unit includes an engine, and the test bench also includes an emissions testing instrument, configured to switch between an engine-only drive mode and a hybrid drive mode, for testing the engine's fuel consumption and emissions performance under different drive modes.

[0033] Furthermore, the constant pressure variable pump is a pressure-compensated variable pump, and the output pressure is maintained within a preset constant range to ensure the stable operation of the hydraulic system.

[0034] Furthermore, the secondary element operates in two modes: a pump mode and a motor mode. During loading, it absorbs mechanical energy and converts it into hydraulic energy, and during release, it converts the hydraulic energy back into mechanical energy for output.

[0035] Furthermore, the accumulator group includes multiple accumulators connected in parallel, and each accumulator is connected to the hydraulic system through an independent control valve to achieve the selection of different capacity combinations.

[0036] Furthermore, the flywheel assembly in the loading unit is used to simulate the inertial load of a vehicle, and the brake is used to simulate the friction braking of a vehicle, and different working conditions can be achieved by adjusting the braking force.

[0037] Furthermore, the measurement unit is set at key nodes in the mechanical transmission path and hydraulic system to simultaneously collect mechanical and hydraulic parameters, thereby achieving synchronous acquisition and comprehensive analysis of mechanical and hydraulic parameters.

[0038] In one embodiment, the engine of the power input unit provides the system's original power output; the couplings, gearboxes, electromagnetic clutches, and flywheel assembly of the mechanical transmission unit are used to realize power transmission, speed regulation, and load simulation; the constant pressure variable pump, accumulator group, secondary components, hydraulic valves, and pipeline system of the hydraulic system are used to realize energy conversion, storage, and recovery; the brakes of the loading and braking unit are used to simulate vehicle braking and external load conditions; the speed and torque sensors, pressure sensors, flow sensors, and displacement sensors of the measurement unit are used to monitor the system's operating status in real time; and the electric motors, gear pumps, oil tanks, oil filters, cooling and safety control components of the auxiliary unit are used to maintain stable system operation.

[0039] In one embodiment, such as Figure 1 As shown, the coupling includes a first coupling 11, a second coupling 18, a third coupling 21, a fourth coupling 30, a fifth coupling 33 and a sixth coupling 35, and each coupling is equipped with a speed and torque sensor. The electromagnetic clutch includes a first electromagnetic clutch 13, a second electromagnetic clutch 26 and a third electromagnetic clutch 16; The secondary element includes a first secondary element 31 and a second secondary element 32; The hydraulic control valve group includes a first valve 6, a second valve 9, a third valve 41, a fourth valve 43, and a servo valve 46; The brake includes a first brake 22 and a second brake 36; The flywheel assembly includes a first flywheel assembly 20 and a second flywheel assembly 34; The pressure sensor includes a first pressure sensor 7, a second pressure sensor 39 and a third pressure sensor 40; The flow sensor includes a first flow sensor 14, a second flow sensor 19, a third flow sensor 23, and a fourth flow sensor 45; The engine 10 is connected to an emission testing instrument 24. The engine 10 is connected to the first coupling 11. The first coupling 11 is connected to a first transfer case 12. The first transfer case 12 is connected to the first electromagnetic clutch 13 and the second electromagnetic clutch 26 respectively. The first electromagnetic clutch 13 is connected to an automatic transmission 15, the automatic transmission 15 is connected to the third electromagnetic clutch 16, the third electromagnetic clutch 16 is connected to a second transfer case 17, the second transfer case 17 is connected to the second coupling 18 and the multi-plate electromagnetic clutch 29 respectively, and the automatic transmission 15 is connected to a gear position detector 28. The second coupling 18 is connected to the first flywheel assembly 20, the first flywheel assembly 20 is connected to the third coupling 21, and the third coupling 21 is connected to the first brake 22; The multi-plate electromagnetic clutch 29 is connected to the fourth coupling 30, the fourth coupling 30 is connected to the first secondary element 31, the first secondary element 31 is connected to the oil tank 57 through the fourth oil filter 55, the third valve 41, and the first overflow valve 8 respectively, and a second flow sensor 19 is provided between the first secondary element 31 and the first overflow valve 8. The second electromagnetic clutch 26 is connected to the constant pressure variable pump 27, the constant pressure variable pump 27 is connected to the oil tank 57, and a second oil filter 50 is provided between the constant pressure variable pump 27 and the oil tank 57. The constant pressure variable pump 27 is connected to the first overflow valve 8, and a first flow sensor 14 and a one-way valve 25 are provided between the constant pressure variable pump 27 and the first overflow valve 8. It also includes a secondary variable cylinder 38, which is connected to the servo valve 46. The servo valve 46 is connected to the gear pump 52 and the oil tank 57 respectively. A first oil filter 44 and a fourth flow sensor 45 are provided between the servo valve 46 and the gear pump 52. The gear pump 52 is connected to a motor 51. The gear pump 52 is connected to the oil tank 57 through a second overflow valve 53. The gear pump 52 is connected to the oil tank 57 through a third oil filter 54. A second pressure sensor 39 and a third pressure sensor 40 are provided between the secondary variable cylinder 38 and the servo valve 46. The secondary variable cylinder 38 is connected to the first secondary element 31. The secondary variable cylinder 38 is also connected to a displacement sensor 37. The second secondary element 32 is connected to the oil tank 57 through the fifth oil filter 56, the second secondary element 32 is connected to the oil tank 57 through the secondary element variable control component 42, the second secondary element 32 is connected to the oil tank 57 through the fourth valve 43, the second secondary element 32 is connected to the first overflow valve 8 through the second valve 9, a third flow sensor 23 is provided between the second valve 9 and the second secondary element 32, and a first pressure sensor 7 is provided between the second valve 9 and the first overflow valve 8; The second secondary element 32 is connected to the fifth coupling 33, the fifth coupling 33 is connected to the second flywheel assembly 34, the second flywheel assembly 34 is connected to the sixth coupling 35, and the sixth coupling 35 is connected to the second brake 36. It also includes a pre-compressed air filter 47, an oil tank thermometer 48, and an oil tank level gauge 49, all of which are connected to the oil tank 57. It also includes an energy storage unit 5, which is connected to the first overflow valve 8 via a first valve 6; All oil filters are equipped with alarm functions.

[0040] The accumulator in the accumulator group 5 is a hydraulic accumulator.

[0041] Using the accelerator pedal 1 and brake pedal 2 as signal input devices and driver command input interfaces, pressing the accelerator pedal 1 generates an electrical signal representing the throttle opening or power demand, while pressing the brake pedal 2 generates a braking request signal. These signals are sent to the control system of the test bench to simulate the driving operation of a real vehicle and trigger the corresponding control logic. The first angle sensor 3 and the second angle sensor 4 are respectively installed on the rotating shafts of the accelerator pedal 1 and brake pedal 2 to measure the angle or displacement of the two pedals when pressed.

[0042] Compared with the prior art, the present invention has the following advantages: Achieving multi-configuration switching and significantly improving the versatility of the experimental platform: This invention enables the experimental platform to switch between series and parallel hydraulic hybrid power structures on the same platform by setting up a linkage and interlocking mechanism between electromagnetic clutches (first electromagnetic clutch, third electromagnetic clutch, and second electromagnetic clutch). Compared with existing experimental platforms designed only for a single configuration, this invention can complete experimental research on different structural forms without changing the hardware system, significantly improving the versatility and utilization of the experimental platform.

[0043] This invention constructs a unified mechanical-hydraulic coupling testing system to improve system analysis capabilities. By deploying multiple sensors at key locations in both the mechanical and hydraulic systems, it enables the simultaneous acquisition and comprehensive analysis of parameters such as speed, torque (mechanical side, blue portion in the diagram), pressure, and flow rate (hydraulic side, red portion in the diagram). Compared to existing technologies where parameters are scattered and monitoring is incomplete, this invention comprehensively reflects the energy transfer process and working mechanism of the hydraulic hybrid power system, improving the completeness and reliability of experimental data.

[0044] Supporting multi-condition engine performance testing with enhanced functionality: This invention enables flexible switching between hybrid drive mode and engine-only drive mode, and, combined with an emissions testing device, allows for testing of engine fuel consumption and emissions performance. Compared to existing test benches that only focus on power transmission testing, this invention expands the engine performance evaluation capabilities, giving the test platform stronger comprehensive testing capabilities.

[0045] Research on Multi-Load Cooperative Control and Energy Recovery in a Constant Pressure System: This invention constructs a constant pressure hydraulic system through the coordinated design of a constant pressure variable pump, accumulator group, and secondary components, achieving multi-load cooperative control (CPS mode) and the recovery and reuse of hydraulic energy. Simultaneously, by adjusting the accumulator capacity and charging pressure, the impact of different energy storage conditions on energy recovery efficiency can be studied. Compared to the lack of systematic energy recovery research methods in existing technologies, this invention can more realistically simulate the energy management process of a hydraulic hybrid power system.

[0046] This invention possesses the capability to simulate vehicle braking and inertial loads, resulting in more realistic operational condition simulations. By configuring brakes (first and second brakes) to simulate vehicle friction braking and a flywheel assembly (second flywheel assembly) to simulate vehicle inertial loads, it can recreate the dynamic response characteristics of a vehicle during actual operation. Compared to the insufficient load simulation capabilities of existing experimental platforms, this invention provides an experimental environment closer to actual operating conditions, enhancing the engineering reference value of the experimental results.

[0047] Adjustable accumulator array enhances experimental flexibility and research depth: This invention employs an accumulator array composed of multiple accumulators of varying volumes, with the connection method selected via a control valve, making the system's energy storage characteristics adjustable. This design can be used to study the impact of different energy storage capacities on system performance and the effect of different charging pressures on energy recovery efficiency, thereby improving the applicability of the experimental setup in teaching and research.

[0048] The system boasts high safety and reliability: This invention effectively improves the safety and stability of system operation by setting up an overflow valve (first overflow valve) for overpressure protection, an oil filter to ensure the cleanliness of hydraulic oil, and an electromagnetic control valve to achieve emergency unloading, thus meeting the requirements of long-term experimental operation.

[0049] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0050] It will be readily understood by those skilled in the art that this invention includes any combination of the inventive description and specific embodiments outlined in the foregoing specification, as well as the various parts shown in the accompanying drawings. Due to space limitations and for the sake of brevity, not all of these combinations have been described in detail. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

[0051] Although embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A multifunctional hydraulic hybrid power system experimental platform, characterized in that, include: A power input unit, including an engine, is used to provide mechanical power output; The mechanical transmission unit connected to the power input unit includes a connecting coupling, a gearbox, and an electromagnetic clutch, used for power transmission and switching of transmission paths; The hydraulic system connected to the mechanical transmission unit includes a constant pressure variable pump, an accumulator group, at least one pair of secondary components, and a hydraulic control valve group, used for the conversion, storage, and recovery of mechanical energy and hydraulic energy; The loading unit connected to the hydraulic system includes a brake and a flywheel assembly, used to simulate external loads and inertial loads; The measuring unit connected to the mechanical transmission unit, the hydraulic system, and the loading unit includes a speed and torque sensor, a pressure sensor, and a flow sensor; in, The electromagnetic clutch in the mechanical transmission unit is configured to include at least a clutch assembly and a second clutch. The clutch assembly and the third clutch are connected by a linkage and interlock control relationship, such that: When the clutch group is engaged and the third clutch is disengaged, the output of the power input unit is transmitted in parallel with the hydraulic system through the mechanical transmission path, forming a parallel hydraulic hybrid power structure. When the third clutch is engaged and the clutch group is disengaged, the output of the power input unit is transmitted through the hydraulic system, forming a series hydraulic hybrid power structure. The hydraulic system is a constant pressure system. The constant pressure variable pump is used to maintain the system pressure stability. The secondary element converts mechanical energy into hydraulic energy under load conditions and stores it in the accumulator group. The accumulator group includes multiple accumulators of different volumes, which are selectively connected to the hydraulic system via control valves.

2. The multifunctional hydraulic hybrid power system test bench as described in claim 1, characterized in that, The clutch assembly includes a first electromagnetic clutch and a third electromagnetic clutch, which are respectively located on the mechanical transmission path for synchronous engagement or disengagement.

3. The multifunctional hydraulic hybrid power system test bench as described in claim 1, characterized in that, An electrical interlock or control logic interlock is provided between the clutch assembly and the second clutch, allowing only one power transmission path to be in operation at any given time.

4. The multifunctional hydraulic hybrid power system test bench as described in claim 1, characterized in that, The hydraulic control valve group includes a second valve for switching the system operating mode. When the test bench is working in a series hydraulic hybrid structure, the second valve is opened to make the hydraulic system form a constant pressure network to simulate multi-load coordinated control conditions.

5. The multifunctional hydraulic hybrid power system test bench as described in claim 1, characterized in that, The power input unit includes an engine, and the test bench also includes an emissions testing instrument, configured to switch between engine-only drive mode and hybrid drive mode for testing the engine's fuel consumption and emissions performance under different drive modes.

6. The multifunctional hydraulic hybrid power system test bench as described in claim 1, characterized in that, The constant pressure variable pump is a pressure-compensated variable pump, and the output pressure is maintained within a preset constant range.

7. The multifunctional hydraulic hybrid power system test bench as described in claim 1, characterized in that, The secondary element operates in two modes: pump mode and motor mode. During loading, it absorbs mechanical energy and converts it into hydraulic energy. During release, it converts the hydraulic energy back into mechanical energy for output.

8. The multifunctional hydraulic hybrid power system test bench as described in claim 1, characterized in that, The accumulator group includes multiple accumulators connected in parallel, and each accumulator is connected to the hydraulic system through an independent control valve.

9. The multifunctional hydraulic hybrid power system test bench as described in claim 1, characterized in that, The flywheel assembly in the loading unit is used to simulate the inertial load of a vehicle, and the brake is used to simulate the friction braking of a vehicle. Different working conditions can be achieved by adjusting the braking force.

10. The multifunctional hydraulic hybrid power system test bench as described in claim 1, characterized in that, The measuring unit is located at the nodes of the mechanical transmission path and the hydraulic system to simultaneously collect mechanical and hydraulic parameters.

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