Low-speed machine piston ring temperature measuring system

Abstract

The invention relates to a low-speed machine piston ring temperature measuring system, which is characterized in that a specially-made self-adaptive piston ring temperature sensor is in direct contact with a piston ring for measurement, the sensor is composed of a steel pipe fixed section and a steel pipe free section capable of axially stretching, and a temperature measuring probe at the tail end of the free section continuously and elastically abuts against the piston ring under the action of a spring; the multi-degree-of-freedom dynamic motion is effectively compensated; the sensors are distributed in the circumferential direction of the piston ring, and signal wires of the sensors are arranged and fixed along an inner cavity of the piston and are finally connected to the anti-shielding signal processing and transmitting device fixed to the bottom of the piston skirt through threading holes in the piston skirt. Compared with the prior art, the device has the advantages that the temperature of the piston ring can be directly and reliably measured, and the like.

Description

Technical Field

[0001] This invention relates to the field of internal combustion engine condition monitoring technology, and in particular to a low-speed engine piston ring temperature measurement system. Background Technology

[0002] As a key component of large low-speed diesel engines (hereinafter referred to as "low-speed engines"), piston rings not only bear the enormous mechanical load and transient thermal shock generated by combustion, but also come into direct contact with high-temperature, high-pressure, and complex combustion gases, undergoing transient reciprocating motion within the cylinder liner. These harsh service conditions easily lead to abnormally high piston ring operating temperatures, resulting in localized lubricating oil film failure, piston ring jamming, abnormal wear, thermal fatigue fracture, and even cylinder scoring, ultimately seriously threatening the operational safety, reliability, and economy of low-speed engines. Real-time piston ring operating temperature is a core parameter for accurately assessing its operating status and predicting potential failures. However, because piston rings are always within a closed combustion chamber, moving and rotating within the ring grooves, and are relatively thin, the operating space is extremely limited. Therefore, how to accurately and dynamically capture the true operating temperature of piston rings has always been a major technical challenge for both academia and industry. Meanwhile, in response to the national strategic call to break through key core technologies and promote the intelligent upgrading of industries in the field of high-end equipment manufacturing, this study aims to solve the problem of accurate online measurement of piston ring temperature in low-speed engines, lay the foundation for building an intelligent operation and maintenance system based on condition monitoring, and effectively avoid catastrophic accidents, reduce maintenance costs and improve the overall operating efficiency of the machine. This has important scientific significance and engineering application value.

[0003] In the field of internal combustion engine condition monitoring technology, in order to obtain the thermal load data of piston assembly, various temperature measurement methods have been disclosed in the prior art. From the perspective of measurement method, they can be divided into contact measurement and non-contact measurement.

[0004] In terms of measurement methods, for example, Chinese patent CN120740992A discloses the use of infrared sensors to directly measure piston rings. The core principle of non-contact infrared thermometry is to detect the infrared energy radiated from the surface of an object and convert it into a temperature value. However, between the infrared sensor on the piston ring and cylinder liner, there may be media such as lubricating oil film, oil mist from combustion, and carbon soot. These media will absorb and scatter infrared radiation, thereby attenuating the signal strength, resulting in the measured temperature being lower than the actual value.

[0005] Therefore, almost all practical applications currently employ contact-based temperature measurement. This involves transmitting measurement data, and there are three main methods: wired transmission, storage-based transmission, and data transfer without data transmission. Storage-based transmission is similar to a black box, meaning data can only be obtained upon disassembly and cannot be acquired in real-time.

[0006] For contact-based data transmission, Chinese patents CN112146884A and CN210665069U disclose methods that use a linkage mechanism, commonly known as a "grasshopper mechanism," to guide the signal lines of sensors such as thermocouples. An inherent drawback of this method is that the signal cables are highly susceptible to fatigue fracture during the high-speed reciprocating motion of an internal combustion engine. Furthermore, the complex mechanical structure not only requires significant modifications to the engine itself but also severely impacts the reliability and applicability of the measurement system. Data storage-based measurement (such as that disclosed in Chinese patent CN102156005A) encapsulates the acquisition and storage unit inside the piston, avoiding cable issues. However, its operating mode is offline acquisition, meaning the engine must be disassembled after shutdown to read the data, making real-time monitoring and fault diagnosis impossible.

[0007] Meanwhile, the write speed and capacity of existing micro-memories are insufficient to meet the requirements for the large amounts of data generated by transient temperature measurements. To overcome these shortcomings, wireless transmission technology has become a mainstream research direction. It utilizes Bluetooth, ZigBee, or proprietary radio frequency protocols for data transmission, as exemplified by Chinese patents CN106908164A and CN102749149A. Among these, the system represented by Chinese patent CN110350667A is relatively complete, disclosing a wireless transmission scheme for internal combustion engine piston temperature based on wireless charging. This scheme integrates sensors, signal processing units, and wireless transmitters inside the piston, achieving real-time wireless transmission of piston temperature.

[0008] However, all existing contact-based temperature measurement technologies, whether wired or wireless, share a common technical drawback: they measure the temperature of the piston body (such as the piston crown center, ring land, or piston cavity), not the direct operating temperature of the piston rings. The piston body temperature serves only as an indirect proxy parameter for the piston ring thermal state, and due to thermal resistance between the piston rings and the piston body, using the piston body temperature as the piston ring temperature results in significant measurement delays and inaccuracies. As a key component that directly exchanges heat and rubs against high-temperature gases and the cylinder liner, the piston ring's temperature is a core parameter affecting lubrication, wear, and sealing performance. Currently, the industry has not yet developed a technology capable of directly and in-situ measuring the piston ring operating temperature.

[0009] The main technical bottlenecks of this defect include the following three aspects: First, the installation and reliability of sensors. During assembly and operation, piston rings undergo axial movement, circumferential rotation, and radial contraction and expansion along the ring groove. This multi-degree-of-freedom dynamic characteristic makes any solution for rigidly mounting sensors on the piston ring prone to failure during assembly due to alignment difficulties, or sensor damage due to relative motion during operation. Second, the integration of electronic systems. Telemetry devices need to be laid out around the extremely limited space of the piston ring and withstand severe vibration and impact loads, while adapting to the movement and rotation of the piston ring within the ring groove; currently, there is a lack of feasible designs. Simultaneously, there is a lack of real-time and high-charging-efficiency power supply solutions for low-speed engine scenarios. Third, the challenge of signal transmission integrity. In the extreme and harsh environment of low-speed engines, wireless signals are susceptible to attenuation, shielding, and multipath effects; in particular, the shielding problem of signals transmitted from within the metal ring groove remains unresolved.

[0010] Therefore, without drastically altering the internal structure of the low-speed engine, how to achieve in-situ, real-time, and high-precision measurement of the transient temperature of the piston rings, while simultaneously improving the reliability and operability of the system, is a key technical problem that urgently needs to be solved in this field. Summary of the Invention

[0011] The purpose of this invention is to provide a low-speed engine piston ring temperature measurement system in order to overcome the shortcomings of the existing technology.

[0012] The objective of this invention can be achieved through the following technical solutions: A low-speed engine piston ring temperature measurement system includes a temperature detection device, a wireless data transmission device, a wireless data receiving device, and a diagnostic device connected in sequence. The wireless data receiving device is located on the partition of the scavenging chamber of the low-speed engine. The wireless data transmission device is located at the bottom of the piston skirt inside the cylinder liner of the low-speed engine. Multiple temperature detection devices are provided, each distributed at intervals along the circumference of the piston ring and embedded in the piston head. They are connected to a wireless data transmission device via a communication cable. The communication cable is laid along a predetermined path inside the piston cavity, with its second end passing through a wire hole opened on the piston skirt and connecting to the wireless data transmission device. Each temperature detection device includes a fixed section of copper tube and a free section of copper tube. A spring is provided on the free section of copper tube, and one end of the free section is connected to the fixed section of copper tube, while the other end is equipped with a temperature probe. The fixed section of copper tube is installed inside the piston body. The temperature probe extends to the surface of the groove inside the piston body and contacts the inner surface of the piston ring side located in the groove. Under the action of the spring, it achieves compensation for axial movement, circumferential rotation, and radial expansion and contraction.

[0013] The copper tube fixing section includes a screw and a locking nut on the screw. The screw includes a base, a support section, and a guide section connected in sequence. The support section has external threads on its outer side. The locking nut is sleeved on the support section and mates with the external threads on the support section. At least the guide section has a hollow channel. One end of the free section of the copper tube is inserted into the hollow channel, and the other end has a second support step. The connection between the support section and the guide section forms a first support step. The two ends of the spring are respectively supported on the first support step and the second support step.

[0014] The support section is provided with a hollow channel, and the hollow channel in the support section is connected to the hollow channel in the guide section.

[0015] The diameter of the free section of the copper tube is smaller than the diameter of the hollow channel.

[0016] The angle between the axis of the copper tube fixing section and the piston rod can be selected as 30°, 60°, or 90°. 30° is used when measuring the temperature of the first piston ring, 60° when measuring the temperature of the second piston ring, and 90° when measuring the temperature of the third piston ring.

[0017] The piston body is provided with multiple piston rings, and multiple temperature detection devices are provided in the grooves corresponding to each piston ring.

[0018] Four temperature sensing devices are installed in the groove corresponding to the piston ring at the top of the piston head, and two temperature sensing devices are installed in the groove corresponding to the piston ring at the top of the other piston heads. All temperature sensing devices in each groove are distributed at equal angles.

[0019] The system also includes a wireless charging receiving coil and a wireless charging transmitting coil. The wireless charging receiving coil and the wireless data transmitting device are integrated in a first protective housing. The first protective housing is specially designed in conjunction with the piston skirt structure of a specified low-speed engine. The first protective housing includes a first arc-shaped main body and a first mounting platform. The first arc-shaped main body has a long strip-shaped tile structure. The curvature of the outer surface is configured to match the contour of the piston skirt annular surface to achieve conformal fitting installation. The first mounting platform is extended from one end of the first arc-shaped main body by integral molding. On the two longitudinal sides of the first mounting platform, a number of mounting holes are evenly distributed along the length direction. The mounting holes are used to firmly fix the protective housing to the inner surface of the piston skirt with bolts to resist the severe vibration and impact generated during the operation of the low-speed engine. The wireless charging transmitting coil and the wireless data receiving device are integrated in a second protective housing, which is rigidly fixed to the stationary partition of the low-speed scavenging chamber by a support rod.

[0020] The diagnostic device is configured to perform the following steps: Acquire temperature data collected by each temperature detection device; Based on the temperature data collected by each temperature detection device, the average temperature, temperature fluctuation rate, axial temperature difference and circumferential temperature non-uniformity are extracted respectively. The average temperature, temperature fluctuation rate, axial temperature difference, and circumferential temperature non-uniformity are input into the trained anomaly detection model to obtain the detection results, which include normal, lubrication deterioration, excessive wear, and impending jamming.

[0021] The temperature fluctuation rate The mathematical expression is: in: Represents crankshaft angular velocity. Represents time, It is the crankshaft angle. It measures the piston ring temperature.

[0022] The mathematical expression for the axial temperature difference is: in: It is an axial temperature difference distribution. Represents the circumferential coordinates of the measuring point. The temperature of the first piston ring was measured. The temperature of the first piston ring measured.

[0023] The mathematical expression for the circumferential temperature non-uniformity is: in: It characterizes the overall temperature difference span of the piston ring in the circumferential direction. This represents the total number of measuring points on the loop. Represents the measurement point number. Representing the Instantaneous temperature readings at each measuring point and Representatives selected respectively The maximum and minimum values ​​of the data from each measuring point.

[0024] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention achieves direct in-situ measurement of the piston ring body temperature in low-speed engines. Existing technologies place temperature sensors in locations far from the piston rings, such as the piston body, resulting in indirect measurement. Due to the thermal resistance formed by multiple interfaces between the measurement point and the heat source, this inherent physical property causes the temperature signal to attenuate and be delayed during transmission. This means that existing technologies can only reflect the macroscopic average temperature trend and cannot respond to transient thermal characteristics that indicate early faults. The adaptive sensing structure employed in this invention can compensate for the multi-degree-of-freedom motion of the piston ring in the axial, circumferential, and radial directions, thereby maintaining a continuous and effective heat conduction path between the temperature probe and the piston ring body. This solution eliminates signal distortion from indirect measurements, enabling direct acquisition of high-fidelity piston ring temperatures. Therefore, it can accurately capture transient temperature signals caused by factors such as lubricating oil film rupture, which serve as precursors to serious faults such as cylinder scoring, fundamentally improving the timeliness of fault warnings.

[0025] 2. This invention achieves high reliability, long-term maintenance-free operation, and minimally invasive installation of the measurement system, overcoming the core obstacles to the engineering applicability of existing technologies. The optimized system integration scheme isolates destructive stress, ensuring stable operation of the system during engine overhaul cycles; its installation scheme requires no significant structural modifications to key engine components, possessing minimally invasive or non-destructive characteristics; its integrated online wireless power supply system eliminates the constraint of battery capacity on monitoring continuity. Therefore, this invention solves the aforementioned engineering application bottlenecks and possesses high reliability and engineering applicability.

[0026] 3. A closed-loop intelligent diagnostic capability, from physical data to operation and maintenance decisions, has been constructed, greatly improving the safety, reliability, and cost-effectiveness of condition-based maintenance for low-speed engines. Existing monitoring systems typically function as data acquisition terminals, outputting raw physical quantity data streams. This type of data requires subsequent manual or offline analysis to be transformed into effective information that can guide operation and maintenance, creating a technological gap between data and decision-making. This invention integrates an intelligent diagnostic algorithm module into the system. This module can fuse and analyze real-time multi-point temperature data with engine operating parameters (such as load and speed), autonomously performing feature extraction, trend analysis, and fault mode identification. Its final output is decision recommendations or condition assessments with clear engineering significance, thereby transforming the system from a simple sensor into a closed-loop system from data acquisition to intelligent decision-making, improving the direct usability of information. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the temperature detection device. Figure 3 This is a schematic diagram showing the arrangement of the temperature detection device; Figure 4 This is a schematic diagram of the first protective shell; Figure 5 A schematic diagram of the piston skirt and threading hole; Figure 6 A schematic diagram showing the installation location of the wireless data transmission device; Figure 7 This is a schematic diagram of the software module composition; Figure 8 This is a schematic diagram of the measurement method; Figure 9 This is a schematic diagram of the measurement results; The components include: 1. Temperature detection device; 2. Wireless data transmission device; 3. Wireless data receiving device; 4. External control device; 5. Diagnostic analysis device; 6. Wireless charging transmitting coil; 7. Wireless charging receiving coil; 8. First protective housing; 9. Second protective housing; 10. Piston head; 11. Piston skirt; 12. Piston rod; 13. Piston ring; 14. Cylinder liner; 15. Mounting through hole; 16. Partition plate; 1-1. Fixed section of copper tube; 1-2. Free section of copper tube; 1-3. Temperature probe; 1-4. Spring; 1-5. Communication cable; 1-1-1. Screw; 1-1-2. Locking nut. Detailed Implementation

[0028] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0029] A low-speed engine piston ring temperature measurement system, such as Figure 1 As shown, it includes a temperature detection device 1, a wireless data transmission device 2, a wireless data receiving device 3, and a diagnostic device connected in sequence. In particular, in this embodiment, the wireless data transmission device 2 can also be called an anti-shielding signal processing and transmission device, which has the function of anti-shielding signal. The wireless data receiving device 3 can also be called an intelligent receiving device. The diagnostic device includes an external control device 4 and a diagnostic analysis device 5. The wireless data receiving device 3 is installed on the partition 17 of the scavenging chamber of the low-speed engine. The wireless data transmission device 2 is located at the bottom of the piston skirt 11 inside the cylinder liner of the low-speed engine. External control device 4 and diagnostic analysis device 5 are located outside the cylinder body of the low-speed engine; Multiple temperature detection devices 1 are provided, spaced apart along the circumference of the piston ring and embedded in the piston head 10. They are connected to a wireless data transmission device via communication cables 1-5. The communication cables 1-5 are laid along a predetermined path within the piston cavity, with the second end passing through a wire hole on the piston skirt 11 and connecting to the wireless data transmission device. To address the technical challenge of existing rigid sensors being unable to adapt to the multi-degree-of-freedom dynamic motion (including axial movement, circumferential rotation, and radial expansion and contraction) of the piston ring within the ring groove, a specially designed adaptive piston ring temperature sensor assembly is presented. Specifically, as shown... Figure 2 and Figure 3 As shown, the temperature detection device 1 includes a fixed copper tube section 1-1 and a free copper tube section 1-2. The fixed copper tube section 1-1 and the free copper tube section 1-2 are two core functional areas that work together. A spring 1-4 is provided on the free copper tube section 1-2, and one end of the free copper tube section 1-2 is connected to the fixed copper tube section 1-1, while the other end is equipped with a temperature probe 1-3. The fixed copper tube section 1-1 is installed inside the piston body 10. The temperature probe 1-3 extends to the surface of the inner groove of the piston body 10 and contacts the inner surface of the piston ring located within the inner groove. Under the action of the spring 1-4, it compensates for axial movement, circumferential rotation, and radial expansion and contraction. Because the temperature detection device 1 has adaptive capabilities, in this embodiment, it can also be called an adaptive piston ring temperature sensor.

[0030] In this embodiment, the intelligent receiving device is connected to the external control device 4 via a connecting wire. In this embodiment, the external control device 4 is connected to the diagnostic analysis device 5 via a USB data cable; The copper tube fixing section 1-1 includes a screw 1-1-1 and a locking nut 1-1-2 on the screw 1-1-1. The function of the screw 1-1-1 is to connect with the mounting base pre-machined on the piston body, thereby firmly and sealingly anchoring the entire sensor assembly to the piston body and providing a stable mounting reference. It includes a base, a support section and a guide section connected in sequence. The support section has external threads on its outer side. The locking nut 1-1-2 is sleeved on the support section and mates with the external threads on the support section. At least the guide section has a hollow channel. One end of the copper tube free section 1-2 is inserted into the hollow channel, and the other end has a second support step. The copper tube free section 1-2 can move axially and telescopically relative to the copper tube fixing section 1-1. The connection between the support section and the guide section forms a first support step. The two ends of the spring 1-4 are respectively supported on the first support step and the second support step.

[0031] In this embodiment, with this design, after the temperature detection device 1 is installed, the free section 1-1 of the steel pipe extends from the piston body 10 under the continuous axial thrust applied by the spring, and the temperature probe 1-3 at its end elastically and continuously abuts against the surface of the piston ring 13. Therefore, no matter what slight positional changes occur in the piston ring 13 during operation, the free section 1-1 of the steel pipe can perform real-time, passive adaptive compensation through its own extension and contraction, thereby ensuring that the temperature probe 1-3 and the piston ring 13 always maintain reliable physical contact, ultimately solving the fundamental technical problem of measurement failure or data inaccuracy caused by dynamic changes in the measured object.

[0032] In addition, in some embodiments, the support section is provided with a hollow channel, and the hollow channel in the support section is connected to the hollow channel in the guide section, thereby having a greater range of free movement.

[0033] In some embodiments, the diameter of the free section 1-2 of the copper tube is smaller than the diameter of the hollow channel, thereby providing a certain range of tilt angle movement.

[0034] Generally, the copper tube fixing section 1-1 is installed at an angle. For example, the angle between the axis of the copper tube fixing section 1-1 and the piston rod can be selected as 30°, 60°, or 90°. A 30° angle is used when measuring the temperature of the first piston ring, a 60° angle is used when measuring the temperature of the second piston ring, and a 90° angle is used when measuring the temperature of the third piston ring. Figure 3 As shown, in this embodiment, to achieve direct, in-situ installation of the specially designed adaptive piston ring temperature sensor, the piston head 10 in the low-speed engine piston assembly needs to undergo pre-precision machining to form an installation interface integrating sensing, guiding, and sealing functions. Specifically, the machining mainly includes extending downwards at a preset angle from the bottom of the piston ring groove inside the piston head 10, penetrating to an operable surface inside the piston head, thereby forming an inclined sensor channel; In this embodiment, the upper port of the sensor channel is precisely opened on the bottom surface of the first, second, and third ring grooves of the piston. The geometry and position of this port are precisely designed, and its function is to guide the temperature measuring end of the specially designed adaptive piston ring temperature sensor so that it can pass through the port and elastically abut against the piston ring 13 installed in the ring groove. In this embodiment, the lower port of the sensor channel is machined into a stepped-hole mounting base. Its exterior has a countersunk hole or tapered seat surface for accommodating the seal, while the interior is machined with standard threads (M6 threads in this embodiment). The function of this mounting base is to provide a standardized, high-strength threaded connection interface for the entire sensor's sealing and locking nut assembly. In this embodiment, through the above processing, a functional geometric structure is formed on the piston head, providing a protected physical path directly to the piston ring being measured for the specially designed adaptive piston ring temperature sensor (and its armor line), and providing an installation and positioning reference for realizing the spring adaptive pressure and high-pressure sealing of the sensor in this invention. The system also includes a wireless charging receiving coil 7 and a wireless charging transmitting coil 6. The wireless charging receiving coil 7 and the wireless data transmitting device 2 are integrated into the first protective housing 8. The first protective housing 8 is specially designed in conjunction with the piston skirt structure of the specified low-speed machine. The first protective housing 8 includes a first arc-shaped main body and a first mounting platform. The first arc-shaped main body has a long strip-shaped tile structure. The curvature of the outer surface is constructed to match the contour of the piston skirt annular surface to achieve conformal fitting installation. The first mounting platform is extended from one end of the first arc-shaped main body by integral molding. On the two longitudinal sides of the first mounting platform, a number of mounting holes are evenly distributed along the length direction. The mounting holes are used to firmly fix the protective housing to the inner surface of the piston skirt with bolts to resist the severe vibration and impact generated during the operation of the low-speed machine. The connecting wire between the wireless charging transmitting coil 6 inside the cylinder liner and the anti-shielding signal processing and transmitting device inside the cylinder liner is made of high-temperature resistant Teflon wire. The connecting wires between the specially designed adaptive piston ring temperature sensor inside the cylinder liner and the anti-shielding signal processing and transmitting device inside the cylinder liner are made of high-temperature resistant Teflon wires.

[0035] The shielded signal processing and transmitting device and the wireless charging receiving coil are fixed in the first protective housing by casting with high-temperature epoxy resin. In this embodiment, in order to achieve a reliable electrical connection between the specially designed adaptive piston ring temperature sensor (located at the piston head) and the shielded signal processing and transmitting device (located at the piston skirt), the connecting wires of the specially designed adaptive piston ring temperature sensor and the shielded signal processing and transmitting device are designed with a specific internal wiring and interface structure. In this embodiment, the sensor's connecting wire is laid along a predetermined path within the piston cavity. To ensure that the wire remains structurally stable and protected from thermal damage under the high temperatures and severe vibrations generated during long-term engine operation, it is fixedly bonded to the surface of the piston cavity using a high-temperature resistant, electrically insulating adhesive. To ensure a safe and reliable transition of the signal wire from the piston cavity to the transmitting device mounted on the outer wall of the piston skirt, a dedicated wire-passing hole 16 is pre-machined on the piston skirt. This channel is located at the lower edge of the piston skirt, corresponding to the mounting position of the shielded signal processing and transmitting device. like Figure 5As shown, in this embodiment, the pre-machined wire-passing hole on the piston skirt is designed as an oblique hole, with the hole's orientation at 66° to the horizontal direction. The diameter of the wire-passing hole is 18mm, and the distance between the hole and the center of the piston skirt is 367.52mm. Its dimensions are designed to ensure the smooth passage of the signal wire while maximizing the structural integrity of the piston skirt. This channel enables an orderly transition of the signal path from the high-dynamic, high-temperature environment inside the piston to the relatively stable external environment, providing crucial structural protection for the signal integrity and long-term reliability of the entire measurement system. The anti-shielding signal processing and transmitting device is equipped with two combined solar panels containing a total of 16 rechargeable high-temperature resistant batteries. These rechargeable high-temperature resistant batteries have three power supply modes: operating mode, standby mode, and sleep mode, with power consumption gradually decreasing to save energy. Operating mode: 34mA; Standby mode: 8mA; Sleep mode: 0mA. In this embodiment, the wireless charging transmitting coil is powered by an external power source, and can realize the anti-shielding signal processing and charging function of the transmitting device on the piston through the wireless charging receiving coil when the piston skirt moves to the vicinity of the bottom dead center. like Figure 6 As shown, in this embodiment, to achieve stable installation of the anti-shielding signal processing and transmitting device on the piston skirt, the piston skirt annular surface is pre-machined. The piston skirt in this embodiment is a hollow cylindrical structure. With the central axis of the piston skirt as a symmetry reference, two sets of mounting screw holes are symmetrically machined on the arc segment of its lower edge. Each set contains nine mounting screw holes, totaling eighteen. According to the engineering markings shown in the attached drawings, the thread specification of the mounting screw holes is M3, and its machining depth is 8mm. The wireless charging transmitting coil 6 and the wireless data receiving device 3 are integrated in the second protective housing 9, which is rigidly fixed to the stationary partition of the low-speed scavenging chamber by a support rod.

[0036] The intelligent receiving device and the wireless charging transmitting coil 6 are fixed in the second protective housing 9 using high-temperature epoxy resin casting. In this embodiment, the intelligent receiving device and the wireless charging transmitting coil 6 in the scavenging chamber are housed in a specially designed second protective housing 9, the main structure of which is similar to that of the first protective housing 8. The second protective housing is installed using a specially configured support rod as a connector, which rigidly fixes the housing to the stationary partition of the low-speed machine's scavenging chamber. The specific connection method is as follows: The second protective housing has a mounting platform with threaded holes. One end of the support rod passes through itself via a fastener and is threaded into the threaded hole on the mounting platform, thus fixing the support rod to the housing. The other end of the support rod is threaded into a threaded hole on the stationary partition of the low-speed scavenging chamber via another fastener. Through these two steps, the second protective housing, which houses the smart receiver and wireless charging transmitting coil, is securely anchored to the internal structure of the low-speed scavenging chamber via the support rod. In this embodiment, the intelligent receiving device is equipped with three high-gain antennas, forming a spatial diversity receiving system, which is mounted on the inner wall of the second protective housing. This can significantly combat signal fading caused by piston movement and multipath effects, ensuring reliable signal reception at any position on the piston rings; In this embodiment, the connecting wire between the intelligent receiving device and the external control device needs to pass through the cylinder shell of the scavenging chamber. First, a standardized mounting through hole 15 is machined at a predetermined position on the cylinder shell of the scavenging chamber of the low-speed machine. A hollow sealing connector is installed and fixed within the through-hole, with the signal wire passing through the central channel of the sealing connector. A one-time epoxy resin potting process is performed within the internal cavity of the sealing connector. During potting, a liquid epoxy resin compound is injected into the cavity, completely encapsulating the signal wire passing through it and filling all internal gaps, forming a strong physical bond with the outer sheath of the wire and the inner wall of the connector housing. In this embodiment, the external control device is designed with a power switch to control the power supply from the shielded signal processing and transmitting device, the wireless charging transmitting coil to the external control device itself. Generally, the piston body 10 is provided with multiple piston rings, and multiple temperature detection devices 1 are provided in the grooves corresponding to each piston ring.

[0037] Considering that the working environment of the first ring is more demanding and the temperature changes drastically, four temperature detection devices 1 are installed in the groove corresponding to the piston ring at the top of the piston head, and two temperature detection devices 1 are installed in the groove corresponding to the piston ring at the top of the other piston heads. All temperature detection devices 1 in each groove are distributed at equal angles.

[0038] like Figure 7 As shown, in this embodiment, when the diagnostic analysis device executes instructions, the following functional modules can be implemented: Multi-dimensional data synchronization and visualization module: receives multi-point temperature data streams from the piston ring temperature measurement system in real time; and then visualizes the temperature data of each measuring point on each piston ring in the form of a time series curve on the graphical user interface; Feature Extraction and Status Assessment Module: Based on the received real-time temperature data stream, this module automatically calculates and quantifies a set of preset physical characteristic indicators that characterize the health status of the piston rings. These indicators include at least: Average Temperature and Temperature Fluctuation Rate: Used to assess the overall thermal load level and stability of the piston rings. Axial Temperature Difference: Calculates and analyzes the temperature difference between corresponding measuring points on the upper and lower surfaces of the same piston ring; this temperature difference is used to quantitatively characterize the degree of gas leakage between the ring lands. Circumferential Temperature Non-uniformity: Calculates and analyzes the standard deviation or range of temperatures among multiple measuring points distributed along the circumference of the piston ring; this indicator is used to assess the lubrication status and contact uniformity between the piston rings and cylinder liners. Predictive fault diagnosis module: This module incorporates one or more machine learning models (e.g., anomaly detection algorithms). These models learn multi-dimensional temperature characteristic patterns corresponding to the low-speed engine under historical normal operating conditions to establish a dynamic health status baseline model. During continuous online monitoring, this module compares the temperature characteristic patterns under the current operating conditions with the health status baseline model in real time to automatically identify statistically significant early abnormal deviations indicating potential faults such as lubrication deterioration, excessive wear, or impending seizure. It then generates and outputs a warning signal when preset alarm logic is met. In this embodiment, the diagnostic device is configured to perform the following steps: Acquire temperature data collected by each temperature detection device 1; Based on the temperature data collected by each temperature detection device 1, the average temperature, temperature fluctuation rate, axial temperature difference and circumferential temperature non-uniformity are extracted respectively. The average temperature, temperature fluctuation rate, axial temperature difference, and circumferential temperature non-uniformity are input into the trained anomaly detection model to obtain the detection results, which include normal, lubrication deterioration, excessive wear, and impending jamming.

[0039] Temperature fluctuation rate The mathematical expression is: in: Represents crankshaft angular velocity. Represents time, It is the crankshaft angle. It measures the piston ring temperature.

[0040] The mathematical expression for axial temperature difference is: in: It is an axial temperature difference distribution. Represents the circumferential coordinates of the measuring point. The temperature of the first piston ring was measured. The temperature of the first piston ring measured.

[0041] The mathematical expression for circumferential temperature nonuniformity is: in: It characterizes the overall temperature difference span of the piston ring in the circumferential direction. This represents the total number of measuring points on the loop. Represents the measurement point number. Representing the Instantaneous temperature readings at each measuring point and Representatives selected respectively The maximum and minimum values ​​of the data from each measuring point.

[0042] Specifically, such as Figure 8 As shown, this embodiment utilizes the aforementioned measurement system to design a method for measuring the piston ring temperature of a low-speed engine, including the following steps: S1. Perform data acquisition and wireless transmission. This step is completed on the piston assembly and includes the following sub-steps: S1.1 System Activation: In response to data acquisition commands received from the outside, the shielded signal processing and transmitting device deployed on the piston skirt switches from a low-power standby state to an active working state; S1.2 In-situ temperature sensing: The temperature probe of the specially designed adaptive piston ring temperature sensor maintains continuous physical contact with the piston ring under the action of the elastic bias element, thereby acquiring the temperature of the piston ring to be measured in real time and directly, and converting the temperature information into a raw, temperature-related electrical signal. S1.3 Signal Conditioning and Digitization: The original electrical signal is transmitted to the shielded signal processing and transmitting device through the signal wire. The device then performs signal conditioning operations on the signal, which include at least signal amplification, filtering and analog-to-digital conversion, thereby generating standardized digital temperature data. S1.4 Anti-shielding wireless transmission: The anti-shielding signal processing and transmission device transmits the processed digital temperature data from inside the cylinder liner to the outside through its specially designed antenna and wireless communication protocol; S2. Perform data reception and wired transmission. This step is completed in the low-speed engine scavenging chamber and includes the following sub-steps: S2.1 Signal Reception and Decoding: The intelligent receiving device deployed in the engine scavenging chamber continuously receives and decodes the wireless data signals from the shielded signal processing and transmitting device, restoring them into an effective digital temperature data stream; S2.2 Wired relay transmission: The intelligent receiving device transmits the received digital temperature data stream to the external diagnostic analysis device in real time and without loss through a sealed connecting wire passing through the engine. S3. Perform diagnostic analysis and early warning. This step is completed on the external diagnostic analysis device of the low-speed engine and includes the following sub-steps: S3.1 Data Visualization and Status Monitoring: The received multi-point temperature data stream is visualized in real time on the graphical user interface in the form of time series curves, and can be synchronously displayed in conjunction with other engine operating parameters; S3.2 Health status feature extraction: Automatically and periodically calculate a set of preset physical characteristic indicators that can characterize the health status of piston rings. The indicators include at least average temperature, temperature fluctuation rate, axial temperature difference and circumferential temperature non-uniformity. S3.3 Predictive Fault Diagnosis and Alarm: The real-time calculated temperature characteristic pattern is continuously compared with the pre-established health status baseline model. When a statistically significant abnormal deviation is detected in the current characteristic pattern, and the deviation meets the preset fault alarm logic, an early warning signal is automatically generated and output. To verify the technical feasibility and practical effect of the present invention, the measurement results of this embodiment are provided. Figure 9 This invention relates to a time-domain curve of multi-point temperature data of piston rings acquired using the measurement system under actual operating conditions of a low-speed engine. The figure shows the real-time temperature changes at multiple measuring points distributed along the circumference of the piston ring under a specific load and speed condition. This result directly demonstrates that the system and method described in this invention can achieve direct, dynamic, and multi-point online monitoring of piston ring temperature.

[0043] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A low-speed engine piston ring temperature measurement system, comprising a temperature detection device (1), a wireless data transmission device (2), a wireless data receiving device (3), and a diagnostic device connected in sequence, characterized in that: The wireless data receiving device (3) is mounted on the partition (17) of the scavenging chamber of the low-speed engine. The wireless data transmission device (2) is located at the bottom of the piston skirt (11) inside the low-speed engine cylinder liner. Multiple temperature detection devices (1) are provided, and each temperature detection device (1) is distributed at intervals along the circumference of the piston ring, embedded in the piston head (10), and connected to the wireless data transmission device through a communication cable (1-5). The communication cable (1-5) is laid along a preset path in the piston cavity, and the second end passes through a wire hole opened on the piston skirt (11) and is connected to the wireless data transmission device. The temperature detection device (1) includes a copper tube fixed section (1-1) and a copper tube free section (1-2). A spring (1-4) is provided on the free section (1-2) of the copper tube, and one end of the free section (1-2) of the copper tube is connected to the fixed section (1-1) of the copper tube, and a temperature probe (1-3) is provided on the other end. The fixed section (1-1) of the copper tube is installed inside the piston body (10). The temperature probe (1-3) extends to the surface of the groove inside the piston body (10) and contacts the inner surface of the piston ring side set in the groove. Under the action of the spring (1-4), it realizes the compensation of axial movement, circumferential rotation and radial expansion and contraction.

2. The low-speed engine piston ring temperature measurement system according to claim 1, characterized in that, The copper tube fixing section (1-1) includes a screw (1-1-1) and a locking nut (1-1-2) on the screw (1-1-1). The screw (1-1-1) includes a base, a support section and a guide section connected in sequence. The support section has an external thread on its outer side. The locking nut (1-1-2) is sleeved on the support section and engages with the external thread on the support section. A hollow channel is provided in the guide section. One end of the free section (1-2) of the copper tube is inserted into the hollow channel, and the other end has a second support step. The connection between the support section and the guide section forms a first support step. The two ends of the spring (1-4) are respectively supported on the first support step and the second support step.

3. The low-speed engine piston ring temperature measurement system according to claim 2, characterized in that, The support section is provided with a hollow channel, and the hollow channel in the support section is connected to the hollow channel in the guide section.

4. The low-speed engine piston ring temperature measurement system according to claim 2, characterized in that, The diameter of the free section (1-2) of the copper tube is smaller than the diameter of the hollow channel.

5. The low-speed engine piston ring temperature measurement system according to claim 2, characterized in that, The angle between the axis of the copper tube fixing section (1-1) and the piston rod can be selected as 30 degrees, 60 degrees or 90 degrees.

6. The low-speed engine piston ring temperature measurement system according to claim 1, characterized in that, The piston body (10) is provided with multiple piston rings, and multiple temperature detection devices (1) are provided in the grooves of each piston ring.

7. The low-speed engine piston ring temperature measurement system according to claim 6, characterized in that, Four temperature detection devices (1) are provided in the groove corresponding to the first piston ring at the top of the piston head. Two temperature detection devices (1) are provided in the grooves corresponding to the second and third piston rings. All temperature detection devices (1) in each groove are distributed at equal angles.

8. The low-speed engine piston ring temperature measurement system according to claim 1, characterized in that, The system also includes a wireless charging receiving coil (7) and a wireless charging transmitting coil (6). The wireless charging receiving coil (7) and the wireless data transmitting device (2) are integrated in a first protective housing (8). The first protective housing (8) is specially designed in conjunction with the piston skirt structure of a specified low-speed engine. The first protective housing (8) includes a first arc-shaped body and a first mounting platform. The first arc-shaped body is a long strip-shaped tile structure. The curvature of the outer surface is constructed to match the contour of the piston skirt annular surface to achieve conformal fitting installation. The first mounting platform is extended from one end of the first arc-shaped body by integral molding. Several mounting holes are evenly distributed along the length direction on the two longitudinal sides of the first mounting platform. The mounting holes are used to firmly fix the protective housing to the inner surface of the piston skirt with bolts to resist the severe vibration and impact generated during the operation of the low-speed engine. The wireless charging transmitting coil (6) and the wireless data receiving device (3) are integrated in the second protective housing (9), which is rigidly fixed to the stationary partition of the low-speed scavenging chamber by a support rod.

9. A low-speed engine piston ring temperature measurement system according to claim 7, characterized in that, The diagnostic device is configured to perform the following steps: Acquire the temperature data collected by each temperature detection device (1); Based on the temperature data collected by each temperature detection device (1), the average temperature, temperature fluctuation rate, axial temperature difference and circumferential temperature non-uniformity are extracted respectively. The average temperature, temperature fluctuation rate, axial temperature difference, and circumferential temperature non-uniformity are input into the trained anomaly detection model to obtain the detection results, which include normal, lubrication deterioration, excessive wear, and impending jamming.

10. A low-speed engine piston ring temperature measurement system according to claim 9, characterized in that, The temperature fluctuation rate The mathematical expression is: in: Represents crankshaft angular velocity. Represents time, It is the crankshaft angle. It measures the piston ring temperature; The mathematical expression for the axial temperature difference is: in: It is an axial temperature difference distribution. Represents the circumferential coordinates of the measuring point. The temperature of the first piston ring was measured. The temperature of the first piston ring measured; The mathematical expression for the circumferential temperature non-uniformity is: in: It characterizes the overall temperature difference span of the piston ring in the circumferential direction. This represents the total number of measuring points on the loop. Represents the measurement point number. Representing the Instantaneous temperature readings at each measuring point and Representatives selected respectively The maximum and minimum values ​​in the data from each measuring point.

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