Piston displacement laser detection and electromagnetic proportion control system for ionic liquid hydrogen compressor

Abstract

An ionic liquid hydrogen compressor piston displacement laser detection and electromagnetic proportion control system comprises a plurality of single-stage compression units connected with a radial plunger pump. The single-stage compression unit is formed by connecting a corresponding single-stage mechanical structure and a hydraulic control system; the single-stage mechanical structure comprises an ionic liquid hydrogen compressor, a cylinder body is provided with a notch in the radial direction, a laser displacement sensor is fixed to the cylinder body, the signal output of the laser displacement sensor is connected with the signal input of an upper computer controller, and the laser displacement sensor measures the displacement variation of a piston in the radial direction through the notch in the cylinder body. The data is transmitted to an upper computer controller, and the upper computer controller calculates the displacement of the metal piston in the axial direction according to the conical surface angle, so that the accurate monitoring and control of the position of the piston are realized; the reliability and maintainability of the system are improved, the operation stability of the compressor is improved, the service life of the compressor is prolonged, mechanical damage and noise are reduced, and energy loss is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of ionic liquid hydrogen compressors, and in particular relates to a laser detection and electromagnetic proportional control system for piston displacement of an ionic liquid hydrogen compressor. Background Art

[0002] With the transformation of the global energy structure and the increasing demand for environmental protection, hydrogen, as a clean and sustainable secondary energy source, has gradually become an important part of energy storage and utilization. Hydrogen has the advantages of high energy density and zero emissions. Especially in the field of hydrogen fuel cell vehicles, hydrogen is regarded as an important solution for the decarbonization of future transportation. However, the widespread application of hydrogen faces many challenges, one of which is the storage and transportation of hydrogen. Since the volume energy density of hydrogen at normal temperature and pressure is low, how to efficiently and safely compress and store hydrogen has become the key to the development of hydrogen energy technology.

[0003] Ionic liquid hydrogen compressor is a new type of liquid piston compressor, which uses ionic liquid as compression medium, has extremely low hydrogen solubility and good thermal stability, can play a role in cooling and lubrication during the compression process, and further improve the compression efficiency. The core advantage of ionic liquid hydrogen compressor lies in its efficient heat exchange capacity and low energy consumption. Ionic liquid is almost incompressible and will not contaminate hydrogen, so it can effectively reduce energy loss and improve compression efficiency during the compression process. In addition, ionic liquid compressors can further enhance the heat exchange effect during the gas compression process by increasing the surface area to volume ratio in the compression chamber, so that its total efficiency can reach more than 83%. Therefore, ionic liquid compressors are considered to be one of the most promising compression technologies in future hydrogen refueling stations.

[0004] The piston operation control of the ionic liquid hydrogen compressor has an important impact on the energy efficiency of the compressor and is the basis for ensuring the normal operation of the compressor. The piston motion trajectory of the ionic liquid hydrogen compressor directly affects the dynamic characteristics and energy loss of the compressor. However, due to the extremely flexible dynamic characteristics of the free piston, it is difficult to predict and control the trajectory of the free piston under different working conditions. Most of the existing research focuses on the theoretical level and lacks real-time and precise control of the piston motion trajectory.

[0005] At present, ionic liquid hydrogen compressors mainly use two methods to buffer the operation of pistons: adding mechanical buffer structures and valve-controlled hydraulic cylinder buffer operation control in hydrogen compression cylinders, such as the patent application named "A motion control system for the lower dead point of the free piston of an ionic liquid compressor" (publication number CN117738877A) and the patent application named "A motion control system for the upper dead point of the free piston of an ionic liquid compressor" (publication number CN117738878A). The addition of a mechanical buffer structure will make the hydraulic cylinder structure more complicated, increase the cost and difficulty of design and manufacturing, and at the same time, the mechanical buffer structure still requires the cooperation of a specific throttling buffer hydraulic system to a certain extent to realize the buffer operation control of the piston. The valve-controlled hydraulic cylinder piston buffer operation control is also only to use a throttle valve to perform throttling buffering at a specific time, and the control method is relatively simple. The above two piston control methods only perform throttling buffering on the piston to reduce the impact of the piston on the cylinder body, and cannot accurately control the running trajectory of the piston, cannot ensure the normal operation of the compressor, cannot improve the energy efficiency of the compressor, and cannot completely avoid the impact of the piston on the hydraulic cylinder.

[0006] In summary, the existing ionic liquid hydrogen compressor piston operation monitoring and control has the following deficiencies: (1) In order to reduce the impact of the piston on the lower dead center, the existing ionic liquid hydrogen compressor adds a complex mechanical buffer structure to the piston and the lower cavity of the hydraulic cylinder. The existence of the mechanical buffer structure will increase the cost and difficulty of the compressor processing and manufacturing. The compressor cylinder needs to be divided into multiple parts and then connected by tie rods and threaded connections, which is difficult to process and assemble. At the same time, the mechanical buffer structure still cannot completely avoid the impact and retention of the piston on the lower dead center. (2) In terms of the control of the piston top dead center movement, the existing ionic liquid hydrogen compressor uses a mechanical buffer method or a method of controlling the opening size of the electromagnetic overflow valve to reduce the impact of the piston on the top dead center. This method also divides the compressor cylinder into multiple different parts and installs a speed or displacement sensor in the cylinder body, which is difficult to install and manufacture. (3) The existing ionic liquid hydrogen compressor cannot accurately and real-time monitor and control the running trajectory of the piston during operation. The piston cannot move according to the given running trajectory, and it is impossible to ensure the normal operation of the compressor and completely avoid the impact of the piston on the hydraulic cylinder. Mechanical damage and noise will be generated during the operation of the ionic liquid compressor. Summary of the invention

[0007] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a laser detection and electromagnetic proportional control system for the piston displacement of an ionic liquid hydrogen compressor. The compressor cylinder body is an integrated structure, and the piston operation is controlled by a displacement sensor feedback signal and a valve-controlled hydraulic cylinder, thereby realizing the monitoring and control of the operation of the ionic liquid compressor piston; improving the reliability and maintainability of the system, improving the operating stability and life of the compressor, reducing mechanical damage and noise, and reducing energy loss.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] An ionic liquid hydrogen compressor piston displacement laser detection and electromagnetic proportional control system, comprising a plurality of single-stage compression units connected to a radial piston pump 3;

[0010] The single-stage compression unit is composed of a corresponding single-stage mechanical structure 1 and a hydraulic control system 2 connected together; the single-stage mechanical structure 1 includes an ionic liquid hydrogen compressor composed of a cylinder head 6, a porous medium 7, a cylinder body 8, a cooling water jacket 9, an ionic liquid piston 10, a metal piston 11, and a base 12. A radial notch is opened on the cylinder body 8, and a laser displacement sensor 13 is fixed on the cylinder body 8. The signal output of the laser displacement sensor 13 is connected to the signal input of a host computer controller 23. The laser displacement sensor 13 measures the displacement change of the piston in the radial direction through the notch on the cylinder body 8, and transmits the data to the host computer controller 23. The host computer controller 23 calculates the displacement of the metal piston 11 in the axial direction according to the cone angle, thereby realizing accurate monitoring and control of the piston position.

[0011] When the diameter of the hydraulic cylinder air cavity is significantly larger than the diameter of the oil cavity, the metal piston 11 is designed as a truncated cone-shaped piston with a conical surface; when the diameter of the hydraulic cylinder air cavity is close to or smaller than the diameter of the oil cavity, the metal piston 11 is designed as an I-shaped piston, and the connecting rod of the I-shaped piston is designed with a conical surface.

[0012] The hydraulic control system 2 includes a second electromagnetic proportional directional valve 22, which is connected to the oil circuit on the base 12. The second electromagnetic proportional directional valve 22 is connected via the first electromagnetic proportional directional valve 21, the second relief valve 20, the oil replenishment pump 19 and the accumulator 18. The structure in which the one-way valve 16 and the throttle valve 17 are connected in series is then connected in parallel with the first electromagnetic proportional directional valve 21 and the first relief valve 15. One end of the parallel structure is connected to the radial piston pump 3, and the other end is connected to the oil circuit between the oil replenishment pump 19 and the accumulator 18; the control ends of the first electromagnetic proportional directional valve 21 and the second electromagnetic proportional directional valve 22 are connected to the host computer controller 23.

[0013] The hydraulic capacity of a single piston chamber of the radial piston pump 3 is slightly larger than the oil chamber capacity of the hydraulic cylinder to ensure sufficient supply of hydraulic oil.

[0014] During the operation of the single-stage compression unit, the laser displacement sensor 13 monitors the position of the metal piston 11 in real time according to the designed piston motion curve, and transmits the data to the host computer controller 23. The host computer controller 23 performs feedback comparison based on the position of the metal piston 11 and the operation curve, and adjusts the flow rate of the hydraulic cylinder oil chamber by controlling the valve core displacement of the second electromagnetic proportional directional valve 22, thereby accurately controlling the operation trajectory of the piston.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] (1) The compression cylinder structure of the ionic liquid hydrogen compressor of the present invention eliminates the complex mechanical buffer structure, reduces the requirements for segmented design and manufacturing of the compressor cylinder body, simplifies the processing and assembly process of the compressor cylinder body, reduces the processing and manufacturing cost and difficulty, avoids the complex structure and installation difficulties brought about by the traditional mechanical buffer method, improves the reliability and maintainability of the system, and reduces the risk of failure caused by mechanical wear.

[0017] (2) The ionic liquid hydrogen compressor of the present invention installs a laser displacement sensor on the side of the cylinder body, and measures the piston displacement by opening a groove on the cylinder body. When the diameter of the hydraulic cylinder air cavity is significantly larger than the diameter of the oil cavity, a truncated cone-shaped piston with a conical surface is designed for piston displacement monitoring and control; when the diameter of the hydraulic cylinder air cavity is close to or smaller than the diameter of the oil cavity, an I-shaped piston with a conical surface on the connecting rod is designed for piston displacement monitoring and control.

[0018] (3) The ionic liquid hydrogen compressor of the present invention introduces an intelligent control system, which monitors the piston position in real time through a laser displacement sensor and a host computer controller, and dynamically adjusts the flow and pressure of the hydraulic control system to ensure that the piston running trajectory is consistent with the design curve. This closed-loop control system not only avoids the impact of the piston on the upper and lower dead points, but also significantly improves the operating stability and life of the compressor, and reduces mechanical damage and noise; at the same time, the coordinated use of the accumulator and the oil replenishment pump optimizes the recycling of the hydraulic oil and reduces energy loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the overall structure of the system of the embodiment of the present invention.

[0020] Figure 2 It is a schematic diagram of the specific structure of the system of the embodiment of the present invention.

[0021] Figure 3 This is a schematic diagram of single-stage hydraulic control of an ionic liquid hydrogen compressor in an embodiment of the present invention.

[0022] Figure 4 This is a partial cross-sectional view of the mechanical structure of a single-stage compression unit of an ionic liquid hydrogen compressor system according to an embodiment of the present invention (the diameter of the hydraulic cylinder air cavity is significantly larger than the diameter of the oil cavity).

[0023] Figure 5 This is a partial cross-sectional view of the mechanical structure of a single-stage compression unit of an ionic liquid hydrogen compressor system according to an embodiment of the present invention (the diameter of the hydraulic cylinder air cavity is close to or smaller than the diameter of the oil cavity). DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the embodiments and drawings.

[0025] like Figure 1 As shown, a laser detection and electromagnetic proportional control system for piston displacement of an ionic liquid hydrogen compressor includes five single-stage compression units connected to a radial piston pump 3;

[0026] like Figure 2 As shown, the single-stage compression unit is composed of a corresponding single-stage mechanical structure 1 and a hydraulic control system 2 connected together; the single-stage mechanical structure 1 includes an ionic liquid hydrogen compressor composed of a cylinder head 6, a porous medium 7, a cylinder body 8, a cooling water jacket 9, an ionic liquid piston 10, a metal piston 11, and a base 12. The bottom of the cylinder body 8 is connected to the base 12, and the top of the cylinder body 8 is connected to the cylinder head 6 by screws. The cylinder head 6 is the top sealing component of the single-stage compression unit, and a sealing ring is installed inside it to ensure the sealing of the fluid in the compression cylinder to prevent gas or liquid leakage. This connection method not only ensures the stability of the structure, but also facilitates disassembly and maintenance; the cylinder body 8 is the main structure of the compression unit, and a cooling water flow channel is opened on its outer wall surface for cooling water during the operation of the compressor. The fluid is cooled and dissipated in the process, and the design of the cooling water flow channel can effectively reduce the heat generated during the compression process to avoid affecting the compression efficiency or damaging the equipment due to excessive temperature; a positioning groove is also opened inside the cylinder body 8 to fix the porous medium 7. The porous medium 7 not only plays a supporting role during the compression process, but also can perform secondary cooling on the fluid to further improve the heat dissipation effect; the outer side of the cylinder body 8 is connected to the cooling water jacket 9, and the temperature of the cylinder body 8 is further reduced by circulating cooling water; a sealing ring is installed on the cooling water jacket 9 to prevent cooling water leakage and ensure the normal operation of the cooling system; the ionic liquid piston 10 and the metal piston 11 located below the porous medium 7 inside the cylinder body 8 are the core moving parts of the compression unit, and the two work together to complete the compression of the gas.

[0027] like Figure 2 , Figure 3 , Figure 4As shown, the cylinder body 8 is provided with a radial notch, and the laser displacement sensor 13 is fixed to the cylinder body 8 by means of a sensor fixing plate 14 and screws; when the diameter of the hydraulic cylinder air cavity is significantly larger than the diameter of the oil cavity, the metal piston 11 is designed as a truncated cone-shaped piston with a conical surface; the signal output of the laser displacement sensor 13 is connected to the signal input of the host computer controller 23, and the laser displacement sensor 13 measures the displacement change of the piston in the radial direction through the notch on the cylinder body 8, and transmits the data to the host computer controller 23, and the host computer controller 23 calculates the displacement of the metal piston 11 in the axial direction according to the cone angle, thereby realizing accurate monitoring and control of the piston position. This design not only improves the measurement accuracy, but also simplifies the installation method of the sensor and reduces the difficulty of manufacturing and assembly.

[0028] like Figure 2 , Figure 3 , Figure 5 As shown, when the diameter of the hydraulic cylinder air cavity is close to or smaller than the diameter of the oil cavity, the metal piston 11 is designed as an I-shaped piston, and the connecting rod of the I-shaped piston is still designed with a conical surface. The cylinder body 8 is also provided with a radial notch, and the laser displacement sensor 13 is fixed to the cylinder body 8 through the sensor fixing plate 14 and screws. The laser displacement sensor 13 measures the radial displacement change of the piston through the notch on the cylinder body 8, and transmits the data to the host computer controller 23; the host computer controller 23 calculates the displacement of the metal piston 11 in the axial direction according to the cone angle, thereby realizing accurate monitoring and control of the piston position. This design is suitable for different hydraulic cylinder sizes and has high versatility and flexibility.

[0029] like Figure 2 , Figure 3As shown, the hydraulic control system 2 is composed of a first relief valve 15, a one-way valve 16, a throttle valve 17, an accumulator 18, an oil replenishing pump 19, a second relief valve 20, a first electromagnetic proportional directional valve 21, a second electromagnetic proportional directional valve 22 and other components. These components work together to ensure the stable operation of the hydraulic control system; the second electromagnetic proportional directional valve 22 is connected to the oil circuit on the base 12, and the second electromagnetic proportional directional valve 22 is connected to the accumulator 18 via the first electromagnetic proportional directional valve 21, the second relief valve 20, the oil replenishing pump 19, and the structure after the one-way valve 16 and the throttle valve 17 are connected in series, and then connected in parallel with the first electromagnetic proportional directional valve 21 and the first relief valve 15. One end of the parallel structure is connected to the radial piston pump 3, and the other end is connected to the oil replenishing pump 1 9 and the oil circuit between the accumulator 18; the control ends of the first electromagnetic proportional directional valve 21 and the second electromagnetic proportional directional valve 22 are connected to the host computer controller 23; the radial piston pump 3 is the power source of the hydraulic control system, and the hydraulic volume of its single piston chamber is slightly larger than the volume of the hydraulic cylinder oil chamber to ensure sufficient supply of hydraulic oil; during the operation of the single-stage compression unit, according to the designed piston motion curve, the laser displacement sensor 13 monitors the position of the metal piston 11 in real time, and transmits the data to the host computer controller 23, the host computer controller 23 performs feedback comparison based on the position of the metal piston 11 and the operation curve, and adjusts the flow of the hydraulic cylinder oil chamber by controlling the valve core displacement of the second electromagnetic proportional directional valve 22, thereby accurately controlling the running trajectory of the piston.

[0030] like Figure 2 , Figure 3 As shown, the excess oil in the plunger cavity of the radial piston pump 3 flows back to the accumulator 18 through the first electromagnetic proportional directional valve 21; the first electromagnetic proportional directional valve 21 is also controlled by the host computer controller 23 according to the displacement signal monitored by the laser displacement sensor 13 to ensure the balance and efficient operation of the hydraulic control system; the accumulator 18 replenishes a certain amount of oil for the radial piston pump 3 during the intake stage to ensure that the plunger cavity is always full of hydraulic oil; when the oil pressure in the accumulator 18 is lower than the set value, the oil replenishment pump 19 starts working to replenish the accumulator 18 with oil to maintain the normal operation of the system; the second overflow valve 20, as a safety protection device, automatically opens when the system pressure is too high to prevent the hydraulic system from overloading and ensure the safe operation of the equipment.

Claims

1. A laser detection and electromagnetic proportional control system for piston displacement of an ionic liquid hydrogen compressor, characterized in that: It comprises a plurality of single-stage compression units connected to a radial piston pump (3); The single-stage compression unit is composed of a corresponding single-stage mechanical structure (1) and a hydraulic control system (2) connected together; the single-stage mechanical structure (1) includes an ionic liquid hydrogen compressor connected together by a cylinder head (6), a porous medium (7), a cylinder body (8), a cooling water jacket (9), an ionic liquid piston (10), a metal piston (11), and a base (12); a radial notch is opened on the cylinder body (8); a laser displacement sensor (13) is fixed on the cylinder body (8); a signal output of the laser displacement sensor (13) is connected to a signal input of a host computer controller (23); the laser displacement sensor (13) measures the displacement change of the piston in the radial direction through the notch on the cylinder body (8), and transmits the data to the host computer controller (23); the host computer controller (23) calculates the displacement of the metal piston (11) in the axial direction according to the cone angle, thereby realizing accurate monitoring and control of the piston position.

2. The system according to claim 1, characterized in that: When the diameter of the hydraulic cylinder air chamber is significantly larger than the diameter of the oil chamber, the metal piston (11) is designed as a truncated cone-shaped piston with a conical surface; when the diameter of the hydraulic cylinder air chamber is close to or smaller than the diameter of the oil chamber, the metal piston (11) is designed as an I-shaped piston, and the connecting rod of the I-shaped piston is designed with a conical surface.

3. The system according to claim 1, characterized in that: The hydraulic capacity of a single plunger chamber of the radial plunger pump (3) is slightly larger than the capacity of the hydraulic cylinder oil chamber, so as to ensure sufficient supply of hydraulic oil.

4. The system according to claim 1, characterized in that: The hydraulic control system (2) comprises a second electromagnetic proportional directional valve (22), the second electromagnetic proportional directional valve (22) is connected to the oil circuit on the base (12), the second electromagnetic proportional directional valve (22) is connected via the first electromagnetic proportional directional valve (21), the second overflow valve (20), the oil replenishment pump (19) and the accumulator (18), the structure after the one-way valve (16) and the throttle valve (17) are connected in series, and then connected in parallel with the first electromagnetic proportional directional valve (21) and the first overflow valve (15), one end of the parallel structure is connected to the radial piston pump (3), and the other end is connected to the oil circuit between the oil replenishment pump (19) and the accumulator (18); the control ends of the first electromagnetic proportional directional valve (21) and the second electromagnetic proportional directional valve (22) are connected to the host computer controller (23).

5. The system according to claim 4, characterized in that: During the operation of the single-stage compression unit, according to the designed piston motion curve, the laser displacement sensor (13) monitors the position of the metal piston (11) in real time and transmits the data to the upper computer controller (23). The upper computer controller (23) performs feedback comparison based on the position of the metal piston (11) and the operation curve, and adjusts the flow rate of the hydraulic cylinder oil chamber by controlling the valve core displacement of the second electromagnetic proportional directional valve (22), thereby accurately controlling the operation trajectory of the piston.

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