Gear knocking active control system and method of reciprocating piston type air compressor

Abstract

The invention relates to the technical field of air compressor control, in particular to a gear knocking active control system and method of a reciprocating piston type air compressor, an electromagnet mechanism is integrated in a cylinder cover assembly, and an armature is arranged on a piston assembly; according to the displacement amount of the piston assembly, the reversing moment when the piston assembly reaches the top dead center is determined, and the current air gap length is obtained; according to the gas pressure signal in the cylinder of the air compressor, the reverse thrust of gas in the cylinder to the piston assembly is determined; at the reversing moment, a control instruction is generated according to the reverse thrust and the air gap length, the output electromagnetic attraction force of the electromagnet mechanism is adjusted, the reverse thrust is balanced through the electromagnetic attraction force, and therefore negative torque is eliminated, gear reverse impact is avoided, and efficient mute operation is achieved.

Description

Technical Field

[0001] This invention relates to the field of air compressor control technology, specifically to an active control system and method for gear knocking in a reciprocating piston air compressor. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Commercial vehicles rely on onboard air compressors to supply compressed air for their braking systems, air suspension, and other subsystems. Currently, most air compressors used in commercial vehicles are reciprocating piston air compressors. These compressors are powered by the engine, and their pistons reciprocate within the cylinders to compress the gas.

[0004] In this type of reciprocating piston air compressor, the direction of the output torque changes during a working cycle, generating a negative torque after the piston reaches top dead center and reverses direction. This negative torque causes a violent impact between the driven gear and the drive gear of the air compressor, resulting in gear knocking noise and reducing the life of the gear system.

[0005] To suppress this noise, one common industry solution is to control tooth backlash (such as using a shear gear design), which eliminates backlash through a flexibly connected preloaded gear. Another approach is to reduce residual pressure in the cylinder by controlling the air compressor's unloading rate, thereby reducing negative torque. However, existing noise reduction solutions all have significant drawbacks. Methods that control tooth backlash rely on flexible components connecting the drive gear and preload gear. The introduction of these flexible components reduces the rigidity and reliability of the gear transmission, making it prone to damage under heavy loads. Furthermore, they can easily trigger new high-frequency vibration problems, namely gear squealing.

[0006] The method of suppressing negative torque by controlling the air compressor unloading rate and reducing the residual pressure in the cylinder will directly reduce the effective exhaust volume of the air compressor, significantly reduce its pumping efficiency, and cause the air compressor to start loading more frequently to maintain system pressure, increasing fuel consumption and component wear. Summary of the Invention

[0007] In order to solve the technical problems existing in the background art, the present invention provides an active control system and method for gear knocking of reciprocating piston air compressor, which eliminates gear knocking noise from the source while ensuring the working efficiency and transmission reliability of air compressor.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A first aspect of the present invention provides an active gear knocking control system for a reciprocating piston air compressor, comprising: The cylinder head assembly integrates an electromagnet mechanism. The piston assembly has an armature at its end that can be attracted by an electromagnet mechanism; Displacement sensor is used to obtain the position of the piston assembly inside the air compressor cylinder; Pressure sensor is used to obtain the gas pressure inside the air compressor cylinder; The control unit is electrically connected to the displacement sensor, pressure sensor, and electromagnet mechanism, respectively. The control unit is configured as follows: Based on the position signal obtained by the displacement sensor, determine the reversing moment when the piston assembly reaches the top dead center, and obtain the current air gap length; The reverse thrust of the gas inside the cylinder on the piston assembly is determined based on the gas pressure signal obtained by the pressure sensor. At the moment of reversal, a control command is generated based on the reverse thrust and the air gap length to adjust the output electromagnetic attraction of the electromagnet mechanism, so that the electromagnetic attraction balances the reverse thrust.

[0009] Furthermore, the electromagnet mechanism includes an iron core connected to the cylinder head assembly, with a coil wound around the iron core, and the control unit changes the electromagnetic attraction by adjusting the intensity of the current flowing into the coil.

[0010] Furthermore, the control unit has a pre-stored electromagnetic force MAP, which represents the electromagnetic attraction force under different air gap lengths and different current intensities.

[0011] Furthermore, the control command is a current value, which is obtained by the control unit by querying the electromagnetic force MAP based on the reverse thrust and the target air gap length.

[0012] Furthermore, based on the reverse thrust and air gap length, control commands are generated to adjust the output electromagnetic attraction of the electromagnet mechanism, so that the electromagnetic attraction balances the reverse thrust, specifically: According to the reverse thrust The theoretical electromagnetic force can be obtained by querying the electromagnetic force MAP diagram based on the air gap length. , , The preset value is insufficient to generate negative torque; Let theoretical electromagnetic force According to the theory of electromagnetic force And the current value is obtained by looking up the air gap length on the MAP diagram.

[0013] Furthermore, the control unit is also configured to generate a command to shut off the current of the electromagnet mechanism when the gas pressure signal acquired by the pressure sensor drops to a preset pressure threshold, thereby eliminating the electromagnetic attraction force.

[0014] Furthermore, the displacement sensor is a non-contact displacement sensor, and the installation position is determined by the top clearance calibration method. That is, when the piston assembly is at the top dead center, the measured value is calibrated to be equal to the top clearance value of the air compressor.

[0015] Furthermore, the armature is embedded in the top of the piston assembly.

[0016] Furthermore, the pressure sensor is located on the cylinder head assembly, and its probe is connected to the inside of the cylinder.

[0017] A second aspect of the present invention provides a method for actively controlling gear knocking in a reciprocating piston air compressor, comprising the following steps: Obtain the position of the piston assembly within the air compressor cylinder, determine the reversal time when the piston assembly reaches top dead center, and the current air gap length; Obtain the gas pressure inside the air compressor cylinder to determine the reverse thrust of the gas on the piston assembly; At the moment of reversal, the required current value is determined based on the reverse thrust and the air gap length; the electromagnet mechanism generates an electromagnetic attraction force to balance the reverse thrust based on the current value. When the gas pressure in the air compressor cylinder drops below a preset threshold, the current to the electromagnet mechanism is cut off.

[0018] Compared with existing technologies, one or more of the above technical solutions have the following beneficial effects: 1. This solution uses electromagnetic force to actively and in real-time balance the gas counterforce that causes negative torque, eliminating the conditions for gear knocking at the source of vibration. Compared with the traditional solution that reduces negative torque by increasing the unloading rate, this solution does not require pre-releasing the high-pressure gas in the cylinder, ensuring the full utilization of compressed gas, avoiding the loss of pumping efficiency and energy waste, and achieving the dual goals of quiet operation and high efficiency.

[0019] 2. This solution eliminates the need for structures relying on flexible components such as shear gears, thus preventing the decline in transmission reliability caused by the aging and fatigue of flexible components. Furthermore, since the electromagnetic force acts directly on the piston rather than interfering with the gear meshing process, it does not alter the inherent stiffness characteristics of the gear pair, completely avoiding new NVH (noise, vibration, and harshness) problems such as gear squealing that may arise with traditional shear gear solutions, resulting in superior system durability.

[0020] 3. This solution employs closed-loop feedback control using both displacement and pressure sensors, combined with a pre-set electromagnetic force MAP, enabling real-time and accurate calculation and output of the required balanced electromagnetic force. The electromagnetic actuator boasts a fast response speed, effectively matching engine speed and piston motion frequency. This allows for automatic adjustment of the control strategy based on different operating conditions (such as varying speeds and loads), demonstrating strong adaptability and ensuring optimal vibration and noise reduction under various working conditions.

[0021] 4. The main actuators (electromagnets) and sensing components (displacement and pressure sensors) of this solution are all integrated into the air compressor cylinder head assembly, requiring minimal modification to the existing engine gear transmission system. This design makes the solution suitable not only for new vehicle models but also for upgrading existing commercial vehicles, offering broad application prospects. Attached Figure Description

[0022] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0023] Figure 1 This is a cross-sectional structural schematic diagram of an air compressor piston assembly provided in one or more embodiments of the present invention; Figure 2 This is a schematic diagram of the air compressor drive torque variation curve during air compressor operation provided by one or more embodiments of the present invention; Figure 3 This is a schematic diagram of the cylinder pressure curve of an air compressor during operation, provided by one or more embodiments of the present invention. Figure 4 This is a schematic diagram of the electromagnetic force, current, and air gap length MAP curves provided by one or more embodiments of the present invention.

[0024] In the diagram: 1. Cylinder head assembly; 2. Inlet port; 3. Displacement sensor; 4. Iron core; 5. Coil; 6. Pressure sensor; 7. Exhaust port; 8. Armature; 9. Air compressor cylinder block; 10. Piston assembly. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0027] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0028] Terminology Explanation: A reciprocating piston air compressor is a mechanical device that uses a piston to reciprocate linearly within a cylinder, compressing and delivering gas by changing the cylinder's internal volume. The power source for a vehicle-mounted reciprocating piston air compressor comes from the vehicle's engine. The engine drives a drive gear, which in turn drives a driven gear and a crankshaft. The crankshaft, via a connecting rod, drives the piston to reciprocate linearly, thus achieving the intake, compression, and discharge of gas.

[0029] An armature is a component made of soft magnetic materials (such as low-carbon steel or silicon steel). It does not generate magnetism itself, but it can be strongly attracted by an external electromagnet.

[0030] The control unit, typically a microcontroller or single-chip microcomputer, is responsible for receiving sensor signals, executing control algorithms, and outputting instructions.

[0031] Example 1: As described in the background section, the pneumatic systems (brakes, suspension, gear shifting, etc.) of commercial vehicles (especially heavy-duty trucks and long-haul buses) rely entirely on air compressors to provide compressed air. These onboard air compressors are typically reciprocating piston air compressors. However, the direction of torque on the crankshaft of a reciprocating piston air compressor changes during one working cycle (e.g., Figure 2 As shown, after the piston reaches top dead center and reverses direction, the pressure of the residual compressed gas in the cylinder will be higher than the intake pressure. This residual pressure will push the piston in the opposite direction, thus generating negative torque in the transmission system. Negative torque will cause reverse impact and separation between the driven gear and the drive gear of the air compressor, producing knocking noise.

[0032] One of the commonly used solutions in the industry is to control tooth backlash. The most representative method is to use shear gears, which use flexible elements (such as rubber) to connect two gear plates and always apply a preload to the gear pair to fill the gap and prevent the gears from impacting in the opposite direction when negative torque occurs.

[0033] This solution, by introducing flexible components, alters the high-rigidity characteristics of gear transmission, making it unsuitable for high-power or rapidly changing torque applications. It is also prone to damage under heavy loads. The strength of the flexible components limits the maximum torque they can transmit, and as these components age, their damping effect is lost, potentially leading to damage to the gear assembly and causing more serious malfunctions. At the same time, the introduction of nonlinear flexible and rigid components can easily trigger new high-frequency vibration problems, namely gear squealing.

[0034] Another approach reduces the residual pressure in the cylinder by controlling the air compressor's unloading rate, thereby decreasing the negative torque. This method involves proactively reducing the residual gas pressure in the cylinder when the piston reaches top dead center by opening the exhaust valve in advance or using other methods. Since the negative torque originates from the high-pressure gas pushing against the piston, the reduced pressure naturally decreases the reverse force, thus mitigating gear knocking.

[0035] When compressed gas is released prematurely without being fully exhausted, it means that some of the energy already used to compress the gas is wasted. To achieve the same system pressure, the air compressor needs to start more frequently or operate for longer periods, thus reducing its pumping efficiency and leading to increased energy consumption and fuel consumption (for gasoline vehicles), which contradicts the goal of high efficiency and energy saving. This method does not eliminate the root cause of negative torque; it merely attempts to weaken it, and at the expense of core performance indicators.

[0036] Both existing solutions are essentially passive: The shear gear solution attempts to "buffer" the impact consequences on the torque transmission path, but at this point the gear impact problem has already occurred, and the solution passively makes the impact less loud. The solution of controlling negative pressure passively "weakens" the root cause of negative torque (cylinder pressure). This solution comes at the cost of performance to reduce negative torque, but the gear impact problem caused by negative torque still exists.

[0037] Therefore, this solution uses sensors to monitor the piston position and cylinder pressure in real time, calculates the gas counter-thrust that generates negative torque, and actively applies a balancing force of equal magnitude and opposite direction generated by electromagnetic force to the piston at the moment of piston reversal to counteract the counter-thrust, thereby eliminating negative torque, avoiding gear reverse impact, and achieving efficient and quiet operation.

[0038] The gear knocking active control system for a reciprocating piston air compressor includes: The cylinder head assembly integrates an electromagnet mechanism. The piston assembly has an armature at its end that can be attracted by an electromagnet mechanism; Displacement sensor is used to obtain the position of the piston assembly inside the air compressor cylinder; Pressure sensor is used to obtain the gas pressure inside the air compressor cylinder; The control unit is electrically connected to the displacement sensor, pressure sensor, and electromagnet mechanism, respectively. The control unit is configured as follows: Based on the position signal obtained by the displacement sensor, determine the reversing moment when the piston assembly reaches the top dead center, and obtain the current air gap length; The reverse thrust of the gas inside the cylinder on the piston assembly is determined based on the gas pressure signal obtained by the pressure sensor. At the moment of reversal, a control command is generated based on the reverse thrust and the air gap length to adjust the output electromagnetic attraction of the electromagnet mechanism, so that the electromagnetic attraction balances the reverse thrust.

[0039] As a further embodiment, the electromagnet mechanism includes an iron core connected to the cylinder head assembly, with a coil wound on the iron core, and a control unit changing the electromagnetic attraction by adjusting the intensity of the current flowing into the coil.

[0040] As a further implementation, the control unit has a pre-stored electromagnetic force MAP, which represents the electromagnetic attraction force under different air gap lengths and different current intensities.

[0041] As a further implementation, the control command is a current value, which is obtained by the control unit by querying the electromagnetic force MAP based on the reverse thrust and the target air gap length.

[0042] As a further implementation, a control command is generated based on the reverse thrust and the air gap length to adjust the output electromagnetic attraction of the electromagnet mechanism, so that the electromagnetic attraction balances the reverse thrust. Specifically: According to the reverse thrust The theoretical electromagnetic force can be obtained by querying the electromagnetic force MAP diagram based on the air gap length. , , The preset value is insufficient to generate negative torque; Let theoretical electromagnetic force According to the theory of electromagnetic force And the current value is obtained by looking up the air gap length on the MAP diagram.

[0043] As a further implementation, the control unit is also configured to: when the gas pressure signal acquired by the pressure sensor drops to a preset pressure threshold, generate a command to shut off the current of the electromagnet mechanism, so that the electromagnetic attraction disappears.

[0044] As a further implementation, the displacement sensor is a non-contact displacement sensor, and the installation position is determined by the top clearance calibration method. That is, when the piston assembly is at the top dead center, the measured value is calibrated to be equal to the top clearance value of the air compressor.

[0045] As a further embodiment, the armature is embedded in the top of the piston assembly.

[0046] As a further implementation, the pressure sensor is located on the cylinder head assembly, with its probe end connected to the inside of the cylinder.

[0047] like Figure 1 As shown, the cylinder head assembly 1 is provided with an intake port 2 and an exhaust port 7 to support the compression and exhaust actions of the piston assembly 10.

[0048] like Figure 1As shown, the piston assembly 10 is provided with an armature 8 at its top; the cylinder head assembly 1 is provided with an iron core 4 corresponding to the position of the armature 8, and a coil 5 is provided on the iron core 4; the iron core 4 and the coil 5 form an electromagnet, and when the coil 5 is energized, it generates an attraction force on the armature 8 to counteract the negative torque of the piston assembly 10.

[0049] like Figure 1 As shown, the cylinder head assembly 1 is equipped with a displacement sensor 3 and a pressure sensor 6. The displacement sensor 3 obtains the position of the piston assembly 10, determines the reversing time of the piston assembly 10 and the air gap length between the piston assembly 10 and the electromagnet. Pressure sensor 6 acquires the pressure of the air compressor cylinder. The negative pressure (force that generates negative torque) after the piston assembly 10 reaches top dead center and reverses direction is calculated using the following formula: ; In the formula, The pressure exerted by the gas pressure inside the cylinder on the piston assembly 10. The pressure inside the cylinder. This represents the piston area.

[0050] by Based on this, after the air compressor reaches the top dead center, the control unit is triggered to adjust the current of coil 5, thereby adjusting the attraction between the iron core 4 and the armature 8, so that... Established, among which The preset value (which is insufficient to generate negative torque) is used until the cylinder pressure P ≤ When / S, the current in magnet coil 5 is turned off, the electromagnetic force disappears, and the adjustment ends.

[0051] To achieve the above adjustment process, the following two aspects need to be determined: 1. Determining the Piston Reversal Timing: The reversal timing of the piston assembly 10 needs to be determined using displacement sensor 3. To avoid damaging displacement sensor 3 and ensure its measurement accuracy, the displacement sensor is first calibrated based on the compressor's top clearance. This involves allowing the piston assembly 10 to reach top dead center and recording the measured value of displacement sensor 3 at this point. By continuously adjusting the position of displacement sensor 3 until The value is equal to the air compressor top clearance value c. At this time, the position of displacement sensor 3 is fixed, and the position calibration of displacement sensor 3 is completed.

[0052] During the operation of the air compressor, when the displacement sensor 3 measures... When the value equals the compressor top clearance value c, the piston assembly 10 reaches the top dead center position and begins to reverse. At this time, the control unit is triggered to adjust the current of the coil 5.

[0053] II. Determining the Magnitude of the Current: Since the electromagnetic force is related to both the current and the air gap length, as shown in the following formula: ; In the formula, The attraction between the iron core 4 and the armature 8; The number of electromagnetic coils; Current intensity; The vacuum permeability; The cross-sectional area of ​​the magnetic circuit; The leakage flux coefficient; This is the air gap length.

[0054] The electromagnetic force was calibrated in advance through bench testing or simulation. With current and air gap length MAP diagrams between them, such as Figure 4 As shown; When determining the reversing position of the piston assembly 10 based on the displacement sensor 3, the pressure obtained by the pressure sensor 6 is used. Calculate the gas force Further calculations were performed to determine the theoretical electromagnetic force. ,in To make electromagnetic force Then according to and air gap length Find the current value in the MAP diagram; The control unit controls the coil 5 to operate based on the obtained current value, causing the iron core 4 to generate magnetic force, thereby satisfying the requirement. The suction piston assembly 10 counteracts the negative torque of the air compressor and reduces gear knocking noise.

[0055] Traditional solutions reduce negative torque by releasing high-pressure gas in advance (increasing the unloading rate), which directly wastes the gas that has already been compressed using energy. In contrast, this solution does not interfere with the gas compression and exhaust process at all. The high-pressure gas in the cylinder is fully utilized, ensuring 100% pumping efficiency of the air compressor, reducing energy consumption and engine load, and has the advantage of high efficiency (ensuring pumping efficiency).

[0056] Traditional shear gear solutions merely "mask" or "reduce" the impact noise. This solution, however, eliminates the root cause of the impact: negative torque. By precisely balancing the gas thrust through electromagnetic force, the gear pair maintains a good meshing state throughout the entire cycle, preventing the physical conditions for tooth separation and re-impact. This achieves "root-cause noise reduction" and offers the advantage of high quietness (complete suppression of knocking).

[0057] At the same time, the flexible connecting components in the shear gear scheme have been eliminated. The sensing system and electromagnetic actuator are both mature components, and the overall system structure is closer to rigid transmission, which greatly improves durability and reliability. There is no need to worry about failure caused by the aging of flexible connecting components.

[0058] Regarding the issue of howling, the electromagnetic force in this solution acts on the piston without changing the meshing stiffness and characteristics of the gear pair itself, thus completely avoiding the risk of causing new noise, vibration, and acoustic roughness problems.

[0059] Traditional air compressor design and noise control is a purely mechanical problem. To counteract a rapidly changing force in real time, the response speed and control precision of mechanical components are far from sufficient. Therefore, this solution designs the mechanical system (piston, cylinder head), sensor system (displacement, pressure), and electronic control system (ECU, solenoid coil) as a whole.

[0060] Secondly, in traditional solutions, the preload of the shear gear is fixed; the unloading rate is also usually preset and static. These solutions cannot cope with fluctuations in operating conditions caused by changes in engine speed and load, and therefore can only passively "weaken" the impact / knocking problems caused by negative torque. This solution, however, uses a displacement sensor to determine when to intervene with electromagnetic force, and a pressure sensor and control unit to determine how much electromagnetic attraction to generate for the electromagnet to counteract the negative torque. This "perception-decision-execution" cycle operates in real-time and at high speed, giving the solution "intelligent" and "adaptive" characteristics, enabling it to handle various complex operating conditions.

[0061] Example 2: The active control method for gear knocking in a reciprocating piston air compressor includes the following steps: Obtain the position of the piston assembly within the air compressor cylinder, determine the reversal time when the piston assembly reaches top dead center, and the current air gap length; Obtain the gas pressure inside the air compressor cylinder to determine the reverse thrust of the gas on the piston assembly; At the moment of reversal, the required current value is determined based on the reverse thrust and the air gap length; the electromagnet mechanism generates an electromagnetic attraction force to balance the reverse thrust based on the current value. When the gas pressure in the air compressor cylinder drops below a preset threshold, the current to the electromagnet mechanism is cut off.

[0062] Traditional solutions are passive (such as the elastic buffer of shear gears) or static (such as a fixed unloading rate). This solution, however, is a closed-loop active control system. It can sense the operating conditions (pressure, position) in real time and dynamically adjust the output force. Regardless of the air compressor's speed or load, the system can automatically achieve optimal balance, demonstrating a high degree of intelligence.

[0063] Electromagnetic force has a millisecond-level response speed, which can keep up with changes in engine speed and ensure that the force is applied in a timely and accurate manner every time the piston reaches top dead center, meeting the needs of high-frequency operation of air compressors.

[0064] The system is primarily integrated into the cylinder head and piston of the air compressor, requiring minimal modifications to the engine and gear transmission system. This makes it easier to adapt to existing vehicle models, less restricted by installation space, and more universally applicable.

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A gear knocking active control system for a reciprocating piston air compressor, characterized in that, include: The cylinder head assembly integrates an electromagnet mechanism. The piston assembly has an armature at its end that can be attracted by the electromagnet mechanism; A displacement sensor is used to obtain the position of the piston assembly within the air compressor cylinder; Pressure sensor is used to obtain the gas pressure inside the air compressor cylinder; The control unit is electrically connected to the displacement sensor, pressure sensor, and electromagnet mechanism, respectively. The control unit is configured as follows: Based on the position signal obtained by the displacement sensor, the reversing time when the piston assembly reaches the top dead center is determined, and the current air gap length is obtained. The reverse thrust of the gas inside the cylinder on the piston assembly is determined based on the gas pressure signal obtained by the pressure sensor. At the moment of reversal, a control command is generated based on the reverse thrust and the air gap length to adjust the output electromagnetic attraction of the electromagnet mechanism so that the electromagnetic attraction balances the reverse thrust.

2. The gear knocking active control system for a reciprocating piston air compressor as described in claim 1, characterized in that, The electromagnet mechanism includes an iron core connected to the cylinder head assembly, on which a coil is wound, and the control unit changes the electromagnetic attraction by adjusting the intensity of the current flowing into the coil.

3. The gear knocking active control system for a reciprocating piston air compressor as described in claim 1, characterized in that, The control unit has a pre-stored electromagnetic force map, which represents the electromagnetic attraction force under different air gap lengths and different current intensities.

4. The gear knocking active control system for a reciprocating piston air compressor as described in claim 3, characterized in that, The control command is a current value, which is obtained by the control unit by querying the electromagnetic force MAP based on the reverse thrust and the target air gap length.

5. The gear knocking active control system for a reciprocating piston air compressor as described in claim 1, characterized in that, Based on the reverse thrust and air gap length, control commands are generated to adjust the output electromagnetic attraction of the electromagnet mechanism, so that the electromagnetic attraction balances the reverse thrust. Specifically: According to the reverse thrust The theoretical electromagnetic force can be obtained by querying the electromagnetic force MAP diagram based on the air gap length. , , The preset value is insufficient to generate negative torque; Let the theoretical electromagnetic force According to the theory of electromagnetic force The current value is obtained by looking up the electromagnetic force MAP diagram based on the air gap length.

6. The gear knocking active control system for a reciprocating piston air compressor as described in claim 1, characterized in that, The control unit is also configured to: when the gas pressure signal acquired by the pressure sensor drops to a preset pressure threshold, generate a command to cut off the current of the electromagnet mechanism, so that the electromagnetic attraction disappears.

7. The gear knocking active control system for a reciprocating piston air compressor as described in claim 1, characterized in that, The displacement sensor is a non-contact displacement sensor, and its installation position is determined by the top clearance calibration method. That is, when the piston assembly is at the top dead center, the measured value is calibrated to be equal to the top clearance value of the air compressor.

8. The gear knocking active control system for a reciprocating piston air compressor as described in claim 1, characterized in that, The armature is embedded in the top of the piston assembly.

9. The gear knocking active control system for a reciprocating piston air compressor as described in claim 1, characterized in that, The pressure sensor is located on the cylinder head assembly, and its probe end is connected to the inside of the cylinder.

10. A method for actively controlling gear knocking in a reciprocating piston air compressor, implemented based on the active gear knocking control system for the reciprocating piston air compressor according to any one of claims 1-9, characterized in that... Includes the following steps: The position of the piston assembly in the air compressor cylinder is obtained, and the reversal time when the piston assembly reaches the top dead center and the current air gap length are determined. Obtain the gas pressure inside the air compressor cylinder and determine the reverse thrust of the gas on the piston assembly; At the switching moment, the required current value is determined based on the reverse thrust and the air gap length; the electromagnet mechanism generates an electromagnetic attraction force to balance the reverse thrust based on the current value. When the gas pressure in the air compressor cylinder drops below a preset threshold, the current to the electromagnet mechanism is cut off.

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