Diesel engine on-line monitoring method and system

Abstract

The invention discloses a diesel engine on-line monitoring method and system, and belongs to the technical field of diesel engines. The method comprises the steps that the current rotating speed and the current torque of a diesel engine and first vibration data of all target vibration measuring points are obtained; determining a first target characteristic parameter of the corresponding target vibration measuring point according to the first vibration data of each target vibration measuring point; the first target characteristic parameter comprises a time domain characteristic parameter and a frequency domain characteristic parameter; determining a first parameter threshold value of each first target characteristic parameter according to the current rotating speed, the current torque and each first target characteristic parameter; determining a target parameter threshold value of each first target characteristic parameter according to each first target characteristic parameter, the corresponding first parameter threshold value and a preset threshold value updating condition; determining the running state of the gear train according to each first target characteristic parameter and the corresponding target parameter threshold value; the operation state comprises a normal state and a fault state; and when the operation state is a fault state, sending out early warning information.

Description

Technical Field

[0001] This application relates to the field of diesel engine technology, specifically to a method and system for online monitoring of diesel engines. Background Technology

[0002] The gear system is a crucial component of a diesel engine, used to transmit power and drive the valve train, pump, and other parts to operate in the designed sequence, maintaining the normal operation of the diesel engine. As a critical component of the diesel engine, the gear system is susceptible to various failures such as tooth wear, broken teeth, and broken shafts due to harsh working environments, heavy loads, high speeds, and long-term continuous operation, which in turn affect the overall safety and reliability of the diesel engine. Therefore, it is necessary to provide a reliable online monitoring and early warning solution for diesel engine gear systems. Summary of the Invention

[0003] This invention provides a method and system for online monitoring of diesel engines, enabling online monitoring and early warning of diesel engine gear systems and improving the operational reliability of diesel engines.

[0004] Firstly, a method for online monitoring of a diesel engine is provided. The diesel engine includes a gear system and associated auxiliary components. Multiple target vibration measuring points are arranged on the gear system and the auxiliary components. The online monitoring method for the diesel engine includes: Acquire the current speed and torque of the diesel engine, as well as the first vibration data of each target vibration measurement point; The first target characteristic parameter of the corresponding target vibration measurement point is determined based on the first vibration data of each target vibration measurement point. Determine the first parameter threshold for each first target feature parameter based on the current speed, current torque, and each first target feature parameter; The target parameter threshold of each first target feature parameter is determined based on each first target feature parameter, the corresponding first parameter threshold, and the preset threshold update condition; The operating state of the gear system is determined based on each first target feature parameter and the corresponding target parameter threshold; the operating state includes normal state and fault state. And if the running status is in a fault state, a warning message will be issued.

[0005] In some embodiments, determining the first target characteristic parameter of the corresponding target vibration measuring point based on the first vibration data of each target vibration measuring point includes: The first vibration data of each target vibration measuring point is preprocessed to obtain the first target characteristic parameters of each target vibration measuring point; wherein, the first target characteristic parameters include time domain characteristic parameters and frequency domain characteristic parameters.

[0006] In some embodiments, determining a first parameter threshold for each first target feature parameter based on the current rotational speed, the current torque, and each first target feature parameter includes: Acquire first operating data of the diesel engine within a first operating period; wherein, the first operating data includes the first speed and first torque of the diesel engine, and the second vibration data of each target vibration measuring point; The working condition threshold correspondence is determined based on the first rotation speed, the first torque, the preset rotation speed and torque working condition correspondence, and the second vibration data of each target vibration measuring point. The target operating range is determined based on the current speed, current torque, and the preset speed-torque operating condition correspondence. The first parameter threshold of each first target feature parameter is determined based on the correspondence between the target operating condition range, the operating condition threshold, and each first target feature parameter.

[0007] In some embodiments, determining the working condition threshold correspondence based on the first rotational speed, the first torque, the preset rotational speed-torque working condition correspondence, and the second vibration data of each target vibration measuring point includes: Based on the correspondence between the first speed, the first torque, and the preset speed-torque operating conditions, the operating conditions of the diesel engine are divided into intervals to obtain multiple operating condition intervals. The second target characteristic parameter of each target vibration measuring point is determined based on the second vibration data of each target vibration measuring point and the first preset calculation period; wherein, the first preset calculation period is the calculation period of the second target characteristic parameter; Under the condition of satisfying the preset number of self-learning, calculate the average value and standard deviation of all second target characteristic parameters of each target vibration measuring point in each working condition interval; The second parameter threshold for each second target characteristic parameter in each working condition interval is determined based on the average value and standard deviation of all second target characteristic parameters of each target vibration measuring point in each working condition interval; The correspondence between the operating condition thresholds is determined based on the second parameter threshold of each second target feature parameter in each operating condition interval and the corresponding operating condition interval.

[0008] In some embodiments, the operating conditions include stable operating conditions and variable operating conditions; based on the correspondence between the first speed, the first torque, and the preset speed-torque operating conditions, the operating conditions of diesel fuel are divided into intervals to obtain multiple operating condition intervals, including: Under stable operating conditions, the operating conditions are divided according to the range of the first speed, the range of the first torque, and the preset speed-torque correspondence. When the operating conditions are variable, the operating conditions are divided according to the first division step of the first speed and the second division step of the first torque.

[0009] In some embodiments, determining the second parameter threshold for each second target characteristic parameter in each working condition interval based on the average value and standard deviation of all second target characteristic parameters at each target vibration measuring point within each working condition interval includes: The lower limit of the second parameter threshold is determined based on the average value, standard deviation, and first preset coefficient of all second target characteristic parameters within each working condition interval; The upper limit of the second parameter threshold is determined based on the average value, standard deviation, and second preset coefficient of all second target characteristic parameters within each working condition interval; wherein, the first preset coefficient and the second preset coefficient are the coefficients of the second target characteristic parameter.

[0010] In some embodiments, determining the target parameter threshold for each first target feature parameter based on each first target feature parameter, the corresponding first parameter threshold, and a preset threshold update condition includes: Calculate the average rate of change of each first target feature parameter within a second preset calculation period; If the average rate of change of more than half of the first target characteristic parameters in all target vibration measurement points is less than half of the preset limit, the first parameter threshold is updated to determine the target parameter threshold.

[0011] In some embodiments, the method further includes: when more than half of the first target characteristic parameters in all target vibration measurement points have a rate of change of more than half of a preset limit, issuing a message to focus on the state of the gear train, and recording the number of warnings incremented by one.

[0012] In some embodiments, the method further includes: issuing information about an abnormal gear system status when the number of warnings exceeds a preset number; If the number of warnings is less than or equal to the preset number, the second preset calculation cycle will be shortened by half.

[0013] In some embodiments, determining the operating state of the diesel engine based on each first target feature parameter and the corresponding target parameter threshold includes: If the first target feature parameter is within the corresponding target parameter threshold range, the operating state of the gear system is determined to be normal. If the first target feature parameter exceeds the corresponding target parameter threshold range and the duration reaches the first preset duration or the average change rate of the first target feature parameter reaches the preset limit within the second preset duration, the operating state of the gear system is determined to be a fault state, and an early warning is triggered to enter the fault location mode in order to determine the fault location.

[0014] In some embodiments, the gear system includes a camshaft gear, a crankshaft gear, an idler gear, and a belt pump gear; Methods for determining the location of a fault include: When the first target characteristic parameter of the idler gear triggers the warning, it warns that the crankshaft or crankshaft gear has failed. If the first target characteristic parameter of the idler gear triggers an early warning, and the first target characteristic parameters of all the pump gears meshing with the idler gear also trigger an early warning, an early warning will be issued indicating that the shaft of the idler gear or the idler gear itself has failed. If the first target characteristic parameter of the idler gear triggers an early warning, and one of the belt pump gears meshing with the idler gear triggers an early warning due to the first target characteristic parameter of the belt pump gear, an early warning will be issued indicating a fault in the shaft or belt pump gear of the belt pump gear.

[0015] In some embodiments, the time-domain feature parameters include effective values; the frequency-domain feature parameters include shift frequency amplitude, shift frequency harmonic amplitude, meshing frequency amplitude, meshing frequency harmonic amplitude, and meshing frequency sideband amplitude; the method further includes: If the effective value exceeds the upper limit of the corresponding target parameter threshold and the amplitude of the meshing frequency sideband exceeds the range of the corresponding target parameter threshold, a warning will be issued for a broken tooth fault. If the effective value exceeds the lower limit of the corresponding target parameter threshold, and if the amplitude of any two or more frequencies among the frequency amplitude and frequency multiplier amplitude exceeds the corresponding target parameter threshold range, an early warning will be issued for a broken shaft fault. If there are any two or more frequencies in the meshing frequency amplitude and the meshing frequency harmonic amplitude that correspond to the target parameter threshold range, an early warning will be issued indicating that a tooth surface wear fault has occurred.

[0016] Secondly, an online monitoring system for a diesel engine is also provided. The diesel engine includes a gear train and associated auxiliary components; multiple target vibration measuring points are respectively arranged on the gear train and the auxiliary components; including: The acquisition module is used to acquire the current speed and torque of the diesel engine, as well as the first vibration data of each target vibration measurement point; The first determining module is used to determine the first target characteristic parameter of the corresponding target vibration measuring point based on the first vibration data of each target vibration measuring point. The second determining module is used to determine the first parameter threshold of each first target feature parameter based on the current speed, the current torque and each first target feature parameter; The third determining module is used to determine the target parameter threshold of each first target feature parameter based on each first target feature parameter, the corresponding first parameter threshold, and the preset threshold update condition. The fourth determining module is used to determine the operating state of the gear system based on each first target feature parameter and the corresponding target parameter threshold; the operating state includes normal state and fault state; The issuing module is used to issue early warning information when the running status is in a fault state.

[0017] Beneficial Effects: This application provides a diesel engine online monitoring method and system. The diesel engine online monitoring method includes: acquiring the current speed and current torque of the diesel engine, as well as first vibration data of each target vibration measuring point; determining the first target characteristic parameter of the corresponding target vibration measuring point based on the first vibration data of each target vibration measuring point; the first target characteristic parameter includes time-domain characteristic parameters and frequency-domain characteristic parameters; determining the first parameter threshold of each first target characteristic parameter based on the current speed, current torque, and each first target characteristic parameter; determining the target parameter threshold of each first target characteristic parameter based on each first target characteristic parameter, the corresponding first parameter threshold, and a preset threshold update condition; determining the operating state of the gear system based on each first target characteristic parameter and the corresponding target parameter threshold; the operating state includes a normal state and a fault state; and issuing a warning message when the operating state is a fault state. The diesel engine online monitoring method provided by this application arranges multiple vibration measuring points in the diesel engine gear system and its auxiliary components, and dynamically updates the target parameter threshold of the characteristic parameters corresponding to the vibration data of each vibration measuring point in real time, so as to monitor whether the gear system has a fault in real time and issue a warning when a fault occurs, thereby realizing online monitoring and warning of the gear system and improving the operating reliability of the diesel engine. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart of an online monitoring method for a diesel engine provided in the embodiments of this application; Figure 2 This is a schematic diagram of the arrangement of measuring points in the diesel engine gear system provided in the embodiments of this application; Figure 3 This is a schematic diagram of the first parameter threshold determination process provided in the embodiments of this application; Figure 4 This is a schematic diagram of the target parameter threshold iteration process provided in the embodiments of this application; Figure 5 This is a schematic diagram of the fault early warning and location process provided in the embodiments of this application; Figure 6 This is a flowchart illustrating the triggering of early warning conditions provided in the embodiments of this application; Figure 7 This is a schematic diagram of the process for determining the location of a warning fault provided in the embodiments of this application; Figure 8 This is a flowchart illustrating the process of determining the type of early warning fault provided in the embodiments of this application; Figure 9 This is a schematic diagram of the overall process of the diesel engine online monitoring method provided in the embodiments of this application; Figure 10 This is a schematic diagram of the principle structure of an online monitoring system for diesel engines provided in the embodiments of this application. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0022] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0023] The use of "applies to" or "configured to" in this application implies open and inclusive language, which does not exclude the applicability to or configuration to devices performing additional tasks or steps. Additionally, the use of "based on" implies openness and inclusivity, because processes, steps, calculations, or other actions "based on" one or more of the stated conditions or values ​​may in practice be based on additional conditions or values ​​beyond those stated.

[0024] In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use this application. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be made without using these specific details. In other instances, well-known structures and processes are not described in detail to avoid obscuring the description of this application with unnecessary detail. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0025] The applicant's research revealed that the gear system is a crucial component of a diesel engine, used to transmit power and drive the valve train, pump, and other parts to operate in the designed sequence, maintaining the normal operation of the diesel engine. As a key component of the diesel engine, the gear system is susceptible to various failures such as tooth wear, broken teeth, and broken shafts due to harsh working environments, heavy loads, high speeds, and long-term continuous operation, thus affecting the overall safety and reliability of the diesel engine. Therefore, online monitoring and early warning of the diesel engine gear system has practical engineering significance for improving diesel engine reliability.

[0026] Many scholars and research institutions both domestically and internationally have conducted extensive research on diesel engine gear system monitoring methods. Vibration monitoring, with its advantages of convenient sensor installation and easy signal extraction, has been widely applied and studied. However, due to the numerous excitation components and complex transmission characteristics of diesel engine vibrations, which exhibit nonlinearity and non-stationarity, online monitoring and early warning of diesel engine gear systems pose significant challenges. Vibration-based monitoring of diesel engine gear systems is primarily achieved through two methods: one is to extract feature information using time-domain, frequency-domain, or combined time-frequency methods to assess the gear system's state. Since there are numerous vibration excitation sources during diesel engine operation, the actual collected vibration signals are a comprehensive reflection of the vibrations of many engine components. Therefore, various signal processing methods must be used to analyze and process the original vibration signals to extract key information characterizing the gear system's state. However, due to the complexity of data processing methods, the complexity of the diesel engine's operating environment and structure, and the differences in data processing algorithms under different operating conditions, this approach relies heavily on human experience and cannot be applied to varying operating conditions. Furthermore, as the diesel engine's operating time accumulates, the gear system's state changes, requiring corresponding updates to the threshold values. Therefore, this method is mostly conducted offline and is difficult to apply to online monitoring of diesel engine gear systems under all operating conditions. Another approach is to use neural networks to establish a condition monitoring model for the diesel engine gear system. However, this method requires a large amount of data to complete, and the models may not be applicable to different engine models, resulting in poor applicability.

[0027] In view of this, embodiments of this application provide a diesel engine online monitoring method and system. The diesel engine online monitoring method includes: acquiring the current speed and current torque of the diesel engine, as well as first vibration data of each target vibration measuring point; determining the first target characteristic parameter of the corresponding target vibration measuring point based on the first vibration data of each target vibration measuring point; the first target characteristic parameter includes time-domain characteristic parameters and frequency-domain characteristic parameters; determining the first parameter threshold of each first target characteristic parameter based on the current speed, current torque, and each first target characteristic parameter; determining the target parameter threshold of each first target characteristic parameter based on each first target characteristic parameter, the corresponding first parameter threshold, and a preset threshold update condition; determining the operating state of the gear system based on each first target characteristic parameter and the corresponding target parameter threshold; the operating state includes a normal state and a fault state; and issuing a warning message when the operating state is a fault state. The diesel engine online monitoring method provided by embodiments of this application arranges multiple vibration measuring points in the diesel engine gear system and its auxiliary components, and dynamically updates the target parameter threshold of the characteristic parameters corresponding to the vibration data of each vibration measuring point in real time, so as to monitor whether the gear system has a fault in real time and issue a warning when a fault occurs, thereby realizing online monitoring and warning of the gear system and improving reliability.

[0028] Figure 1 This is a flowchart of an online monitoring method for a diesel engine provided in this application embodiment. On one hand, this embodiment provides an online monitoring method for a diesel engine, such as... Figure 1 As shown, it includes the following steps: Step 110: Obtain the current speed and torque of the diesel engine, as well as the first vibration data of each target vibration measurement point.

[0029] The current speed and torque of the diesel engine can be obtained in real time through sensors.

[0030] Each target vibration measuring point is equipped with a vibration sensor, which can detect the first vibration data of each target vibration measuring point in real time.

[0031] Figure 2 This is a schematic diagram of the arrangement of measuring points in the diesel engine gear system provided in an embodiment of this application. For example, see [link to relevant documentation]. Figure 2 The gear system of a diesel engine mainly includes camshaft gears, crankshaft gears, idler gears, and pump gears. For example... Figure 2 As shown, the gearbox includes idler gear 1, crankshaft gear, and idler gear 2. The auxiliary components of the gearbox include camshaft gear, pump gear 1, pump gear 2, pump gear 3, pump gear 4, pump gear 5, and pump gear 6.

[0032] The arrangement method for each target vibration measurement point is as follows: the optimal installation position of the vibration sensor is on the surface of the diesel engine component being tested. Due to the limited internal space of the diesel engine gear train, installing the vibration sensor can easily disrupt the gear transmission. This application proposes a method for arranging vibration measurement points on the surface of the diesel engine based on the transmission path of the vibration signal and the structure of the diesel engine, as detailed below: 1. Arrange vibration measuring points on the fixing bolts of the idler gear to detect axial vibration, such as... Figure 2 The first target vibration measuring point is vib1, and the second target vibration measuring point is vib2. Among them, the fixing bolt is the connecting part between the idler gear and the gearbox. The connecting part is the main path for the transmission of vibration energy between different components. The vibration at the fixing bolt of the idler gear can directly reflect the state of the idler gear and the idler shaft.

[0033] 2. Arrange vibration measuring points on the pump body of the conveyor belt to detect radial vibration, for example, by placing them near the center line of the shaft. Figure 2 The vibration measurement points from the third target vib3 to the eighth target vib8 directly reflect the condition of the pump gears and shafts.

[0034] Third, by arranging vibration measuring points on the surface of the gearbox, vibrations in the vertical, horizontal, and front-back directions can be detected. Figure 2 The vibration measurement point vib9 is the ninth target in the middle. The vibration at this point can be used to help determine the state of the gear system.

[0035] Step 120: Determine the first target characteristic parameter of the corresponding target vibration measuring point based on the first vibration data of each target vibration measuring point.

[0036] Each target vibration measurement point has corresponding first vibration data, and the corresponding first target characteristic parameters can be obtained based on the corresponding first vibration data.

[0037] In some embodiments, determining the first target characteristic parameter of the corresponding target vibration measuring point based on the first vibration data of each target vibration measuring point includes: preprocessing the first vibration data of each target vibration measuring point to obtain the first target characteristic parameter of each target vibration measuring point.

[0038] The first target characteristic parameters include time-domain characteristic parameters and frequency-domain characteristic parameters. The time-domain characteristic parameters include the RMS value (effective value); the frequency-domain characteristic parameters include: rotation frequency amplitude, rotation frequency harmonic amplitude, meshing frequency amplitude, meshing frequency harmonic amplitude, and meshing frequency sideband amplitude.

[0039] Preprocessing includes time-domain analysis, frequency-domain analysis, and time-frequency analysis, which can be set according to actual conditions and are not specifically limited here. For example, performing time-domain analysis on the first vibration data can obtain the corresponding time-domain characteristic parameters, performing frequency-domain analysis on the first vibration data can obtain the corresponding frequency-domain characteristic parameters, and performing time-frequency analysis on the first vibration data can obtain the time-frequency characteristic parameters.

[0040] Step 130: Determine the first parameter threshold for each first target feature parameter based on the current rotational speed, current torque, and each first target feature parameter.

[0041] The first parameter threshold is the initial threshold determination of the corresponding first target feature parameter.

[0042] In some embodiments, determining a first parameter threshold for each first target feature parameter based on the current rotational speed, the current torque, and each first target feature parameter specifically includes the following steps: Step 1: Obtain the first operating data of the diesel engine within the first operating time; wherein, the first operating data includes the first speed and first torque of the diesel engine, as well as the second vibration data of each target vibration measuring point.

[0043] The first running time can be either the historical running time of the diesel engine or the running time of the diesel engine during actual operation. In other words, the initial threshold determination of each first target feature parameter can be based on the historical running data of the diesel engine or on a segment of running data during actual operation. The specific setting can be made according to the actual situation, and no specific limitation is made here.

[0044] The specific value of the first running time can be set according to the actual situation, and no specific limit is made here.

[0045] The first speed and first torque of the diesel engine can be obtained in real time by sensors (e.g., speed sensors and torque sensors).

[0046] Step 2: Determine the working condition threshold correspondence based on the first rotational speed, the first torque, the preset rotational speed and torque working condition correspondence, and the second vibration data of each target vibration measuring point.

[0047] The preset speed and torque operating conditions correspond as follows: each preset speed range and preset torque range corresponds to one operating condition. For example, a speed of 500±20 r / min and a torque of 0 N.m correspond to operating condition one; a speed of 700±20 r / min and a torque of 2000±200 N.m correspond to operating condition two.

[0048] In some embodiments, determining the operating condition threshold correspondence based on the first speed, the first torque, the preset speed-torque operating condition correspondence, and the second vibration data of each target vibration measuring point includes: dividing the operating conditions of the diesel engine into intervals based on the first speed, the first torque, and the preset speed-torque operating condition correspondence to obtain multiple operating condition intervals; determining the second target characteristic parameter of the corresponding target vibration measuring point based on the second vibration data of each target vibration measuring point and a first preset calculation period; wherein, the first preset calculation period is the calculation period of the second target characteristic parameter; calculating the average value and standard deviation of all second target characteristic parameters of each target vibration measuring point in each operating condition interval, provided that a preset self-learning quantity is met; determining the second parameter threshold of each second target characteristic parameter in each operating condition interval based on the average value and standard deviation of all second target characteristic parameters of each target vibration measuring point in each operating condition interval; and determining the operating condition threshold correspondence based on the second parameter threshold of each second target characteristic parameter in each operating condition interval and the corresponding operating condition interval.

[0049] When processing the second vibration data from each target vibration measurement point for characteristic parameters, the calculation period (i.e., the first preset calculation period) and sampling frequency need to be determined. Specifically, the calculation period is determined as follows: the calculation period for time-domain characteristic parameters should not exceed t1 (t1=60*50 / n, where n is the rotational speed in seconds), and the calculation period for the frequency domain should not exceed t2 (t2=60*200 / n, where n is the rotational speed in seconds). The sampling frequency is determined as follows: the sampling frequency should be greater than f1 (f1=20fc, where fc is the meshing frequency in Hz).

[0050] The specific value of the preset self-learning quantity can be set according to the actual situation, and no specific limit is made here.

[0051] Among them, the correspondence between working condition thresholds is the correspondence between working condition intervals, feature parameters and parameter thresholds. It is a relationship comparison table composed of the working condition intervals corresponding to each second target feature parameter and the second parameter thresholds in the corresponding working condition intervals, so as to further determine the first parameter thresholds corresponding to each first target feature parameter in combination with the target working condition intervals and the first target feature parameters.

[0052] In some embodiments, the operating conditions include stable operating conditions and variable operating conditions; the operating conditions of diesel fuel are divided into intervals according to the first speed, the first torque, and the preset speed-torque operating condition correspondence, resulting in multiple operating condition intervals, including: when the operating conditions are stable, the operating conditions are divided according to the range of the first speed, the range of the first torque, and the preset speed-torque operating condition correspondence; when the operating conditions are variable, the operating conditions are divided according to the first division step size of the first speed and the second division step size of the first torque.

[0053] The first segmentation step is the speed segmentation step, and the second segmentation step is the torque segmentation step. The specific values ​​of the first and second segmentation step steps can be set according to actual conditions and are not specifically limited here. Specifically, multi-dimensional operating condition intervals are generated using speed and torque. Each dimension has its own upper and lower limits, and the limits of adjacent segments can overlap. Each dimension requires that there be no gaps between adjacent segments. For stable operating conditions, the intervals are divided using custom speed and torque ranges; for variable operating conditions, other operating conditions are divided into m*n operating condition intervals according to the segmentation step size (m is the speed segmentation step size, and n is the torque segmentation step size). An example stable operating condition setting table is shown in Table 2.

[0054] Table 2: Stable Operating Condition Setting Table

[0055] Specifically, the stable operating condition range is divided according to Table 2. Within the entire diesel engine operating condition range (speed 0~1000rpm, torque 0~10000N.m), in addition to the set stable operating condition range, there is a variable operating condition range. The variable operating condition range is divided into several grid areas according to the step size of 50r / min for speed and 500N.m for torque. Each area represents an operating condition range.

[0056] In some embodiments, determining the second parameter threshold of each second target characteristic parameter in each working condition interval based on the average value and standard deviation of all second target characteristic parameters of each target vibration measuring point in each working condition interval includes: determining the lower limit of the second parameter threshold based on the average value, standard deviation and first preset coefficient of all second target characteristic parameters in each working condition interval; determining the upper limit of the second parameter threshold based on the average value, standard deviation and second preset coefficient of all second target characteristic parameters in each working condition interval; wherein the first preset coefficient and the second preset coefficient are coefficients of the second target characteristic parameter.

[0057] The coefficients for different characteristic parameters vary slightly, and the RMS value coefficients are usually set to 0.9 and 1.1.

[0058] Specifically, multiple operating condition intervals are obtained by dividing the operating condition intervals according to the correspondence between the first speed, the first torque, and the preset speed-torque operating conditions. Parameters such as the filtering range of the original vibration data (e.g., the second vibration data), the characteristic parameter calculation period (e.g., time domain calculation period t1, frequency domain calculation period t2), and the self-learning duration t3 are set. Second vibration data from all target vibration measurement points within each operating condition interval are collected, filtered, and the corresponding second target characteristic parameters are calculated. When the calculated characteristic parameters reach the set self-learning quantity (preset self-learning quantity), the average value (μ) and standard deviation (σ) of all characteristic parameters are calculated. The threshold value (k1(μ-3σ), k2(μ+3σ)) is used as the characteristic parameter threshold (i.e., the first parameter threshold) within that operating condition interval, with the larger of the two values ​​being taken. Here, k1 and k2 are set coefficients, which vary slightly for different characteristic parameters; typically, the RMS value coefficient is set to k1=0.9 and k2=1.1.

[0059] It should be noted that the threshold is automatically generated once a sufficient number of samples are collected for the defined operating condition intervals. There is no need to conduct specific tests for each operating condition interval to generate the threshold; the number of samples required to generate the threshold is automatically accumulated. If the number of samples collected for a certain operating condition is insufficient in a single run, the number of samples continues to accumulate as the diesel engine operates under that condition until the threshold is generated.

[0060] Figure 3 This is a schematic diagram of the first parameter threshold determination process provided in the embodiments of this application. For an example, please refer to... Figure 3 The overall process for determining the first parameter threshold is as follows: First, set the segmentation step size (including the speed segmentation step size and torque segmentation step size), operating condition range, and stable operating condition intervals. Then, divide the operating condition into several operating condition intervals. Set the filtering range, collect vibration data within each operating condition interval, and perform filtering. Set the calculation cycle, calculate and store the feature parameters. Set the self-learning time and determine whether the set self-learning time has been reached. If not, return to the step of collecting vibration data within each operating condition interval and performing filtering. If reached, calculate the average value μ and standard deviation σ of all feature parameters. Finally, set coefficients k1 and k2, and the threshold is generated, i.e., upper limit y1: k2(μ+3σ); lower limit y2: k1(μ-3σ).

[0061] Step 3: Determine the target operating condition range based on the current speed, current torque, and the preset speed-torque operating condition correspondence.

[0062] Specifically, by obtaining the current speed and torque of the diesel engine and matching them with the preset speed-torque operating condition correspondence, the operating condition range (i.e., the target operating condition range) to which the current speed and torque belong can be determined.

[0063] Step 4: Determine the first parameter threshold of each first target feature parameter based on the correspondence between the target working condition range, the working condition threshold, and each first target feature parameter.

[0064] Specifically, after determining the correspondence between operating condition thresholds and the target operating condition range, the first parameter threshold corresponding to each first target feature parameter in the target operating condition range is found in the correspondence between the target operating condition range and the operating condition thresholds, thereby determining the first parameter threshold corresponding to each first target feature parameter.

[0065] Step 140: Determine the target parameter threshold for each first target feature parameter based on each first target feature parameter, the corresponding first parameter threshold, and the preset threshold update condition.

[0066] Among them, the target parameter threshold is the dynamic threshold of each first target feature parameter.

[0067] In some embodiments, determining the target parameter threshold for each first target feature parameter based on each first target feature parameter, the corresponding first parameter threshold, and a preset threshold update condition includes: calculating the average rate of change of each first target feature parameter within a second preset calculation period; and updating the first parameter threshold to determine the target parameter threshold when more than half of the first target feature parameters at all target vibration measurement points have an average rate of change less than half of a preset limit.

[0068] The second preset calculation period is the calculation period for the average value of the first target feature parameters. The specific value can be set according to the actual situation, and no specific limitation is made here.

[0069] The preset limit is the limit of the average rate of change of the first target feature parameter. The specific value can be set according to the actual situation, and no specific limit is set here.

[0070] Specifically, the target parameter threshold iteration process is as follows: dynamic iteration of the threshold is achieved through two methods: periodic updates and continuous tracking of feature parameter changes for timely updates. The specific methods are as follows: Set the average calculation period t4 for the first target characteristic parameter, the average calculation window length q, and calculate the average value of the first target characteristic parameter for each target vibration measurement point; store the average value calculated each time, and increment the average value calculation count by 1.

[0071] Calculate the average change rate of the first target characteristic parameter of each target vibration measuring point. If the average change rate of the first target characteristic parameter of more than half of all target vibration measuring points exceeds the preset limit (which can be set to 10%), then calculate the change rate compared with the average value of the characteristic parameter of the (n-1)th time. If the change rate is less than 1 / 2 threshold limit (5%), then relearn the first parameter threshold of the first target characteristic parameter of all target vibration measuring points to update the first parameter threshold of the first target characteristic parameter of all target vibration measuring points, and obtain the target parameter threshold of the first target characteristic parameter of all target vibration measuring points.

[0072] In some embodiments, the diesel engine online monitoring method further includes: when the average rate of change of more than half of the first target characteristic parameters in all target vibration measurement points exceeds half of a preset limit, issuing information on the state of the gear system to be of particular concern, and recording the number of warnings incremented by one.

[0073] Specifically, if the average rate of change of the first target characteristic parameter of more than half of all target vibration measurement points is greater than 1 / 2 of the preset limit (5%), then the status information of the gear system to be focused on will be issued, and the number of warnings will be b+1.

[0074] In some embodiments, the diesel engine online monitoring method further includes: issuing information about abnormal gear system status when the number of warnings is greater than a preset number; and shortening the second preset calculation cycle by half when the number of warnings (or alarms) is less than or equal to a preset number.

[0075] The default value here is 3 times, and the specific value can be set according to the actual situation. No specific limit is set here.

[0076] Specifically, if the number of warnings b exceeds the preset number, a gear system status abnormality information is issued; if the number of warnings b does not exceed the preset number, the average value calculation period is shortened to half of the second preset calculation period t4.

[0077] Figure 4 This is a schematic diagram of the target parameter threshold iteration process provided in the embodiments of this application. For an example, please refer to... Figure 4The iterative process for the threshold values ​​of the target parameters of each first target feature parameter is as follows: Set the calculation period t4 and the calculation window length q, and calculate the average value of all first target feature parameters for all target vibration measurement points. The number of times the average value of the feature parameters is calculated is n = n + 1. Calculate the rate of change of the average value of all first target feature parameters for all target vibration measurement points (compared to the initial value). Set a preset limit value a for the rate of change, and determine if the number of vibration measurement points whose average rate of change of the first target feature parameters exceeds the limit exceeds half. If not, the process ends. If it does, calculate the rate of change of the average value of the feature parameters (compared to the (n-1)th time). Determine if the rate of change of the average value is greater than half of the preset limit a. If not, relearn the threshold. If yes, issue a warning message for the gear system status, with the number of warning messages b = b + 1. Set a preset limit value c for the warning message (i.e., the number of warning messages c), and determine if the number of warning messages b is greater than the preset number of warning messages c. If it is greater than the preset number of warning messages c, issue a gear system status anomaly message. If not, shorten the second preset calculation period t4, i.e., t4 = ½ * t4, and return to the step of calculating the average value of all first target characteristic parameters of all target vibration measurement points.

[0078] Step 150: Determine the operating state of the gear system based on each first target feature parameter and the corresponding target parameter threshold.

[0079] The operating status includes normal status and fault status.

[0080] In some embodiments, determining the operating state of the diesel engine based on each first target feature parameter and the corresponding target parameter threshold includes: determining the operating state of the gear system as normal when the first target feature parameter is within the range of the corresponding target parameter threshold; and determining the operating state of the gear system as faulty when the first target feature parameter exceeds the range of the corresponding target parameter threshold and the duration reaches a first preset duration or the average change rate of the first target feature parameter reaches a preset limit within a second preset duration, and triggering an early warning to enter the fault location mode to determine the fault occurrence point.

[0081] The specific values ​​of the first preset duration and the second preset duration can be set according to the actual situation, and no specific limitation is made here.

[0082] The target parameter threshold can be a specific numerical value or a range value.

[0083] Specifically, the current engine speed, current torque, and vibration signals (i.e., first vibration data) of each target vibration measurement point are collected. The vibration signals are filtered, and the corresponding first target characteristic parameters are calculated. Based on the current engine speed and current torque, the target operating condition range to which the current operating condition belongs is determined, and the first parameter thresholds of all first target characteristic parameters of all target vibration measurement points within the target operating condition range are obtained. The target parameter threshold for each first target characteristic parameter is determined based on each first target characteristic parameter, its corresponding first parameter threshold, and preset threshold update conditions. Each first target characteristic parameter is compared with its corresponding target parameter threshold to determine whether it is within the corresponding target parameter threshold range. If the first target characteristic parameter is within the corresponding target parameter threshold range, it indicates that the diesel engine gear system is in normal condition. When a first target characteristic parameter exceeds its corresponding target parameter threshold range, and the duration of exceeding the target parameter threshold reaches a set time (i.e., the first preset duration), or the average rate of change of the characteristic parameter reaches a set value (i.e., the preset limit) within a certain time (i.e., the second preset duration), an early warning is triggered, and the system enters fault location mode.

[0084] In some embodiments, the gear train includes a camshaft gear, a crankshaft gear, an idler gear, and a motor-driven pump gear; the method for determining the fault location includes: issuing a warning that the crankshaft or crankshaft gear of the crankshaft gear has failed when a first target characteristic parameter of the idler gear triggers a warning; issuing a warning that the shaft or idler gear of the idler gear has failed when the first target characteristic parameter of the idler gear triggers a warning and the first target characteristic parameters of all motor-driven pump gears meshing with the idler gear trigger a warning; and issuing a warning that the shaft or motor-driven pump gear of the motor-driven pump gear has failed when the first target characteristic parameter of the idler gear triggers a warning and the first target characteristic parameter of one of the motor-driven pump gears meshing with the idler gear triggers a warning.

[0085] Furthermore, after determining that the operating state of the gear system is a fault state, the system enters the fault location mode. The specific process is as follows: if the first target characteristic parameters of the idler gear all trigger the warning, then the crankshaft or crankshaft gear of the crankshaft gear is warned to have a fault; if the first target characteristic parameters of the idler gear and all pumps meshing with the idler gear trigger the warning, then the shaft of the idler gear or the idler gear is warned to have a fault; if the first target characteristic parameters of the idler gear and the target vibration measurement point of a certain pump meshing with the idler gear trigger the warning, then the shaft or gear of that pump is warned to have a fault.

[0086] In some embodiments, the time-domain characteristic parameters include effective values; the frequency-domain characteristic parameters include rotational frequency amplitude, rotational frequency harmonic amplitude, meshing frequency amplitude, meshing frequency harmonic amplitude, and meshing frequency sideband amplitude; the diesel engine online monitoring method further includes: issuing an early warning of a broken tooth fault when the effective value exceeds the upper limit of the corresponding target parameter threshold and the meshing frequency sideband amplitude exceeds the range of the corresponding target parameter threshold; issuing an early warning of a broken shaft fault when the effective value exceeds the lower limit of the corresponding target parameter threshold and the amplitudes corresponding to any two or more frequencies among the rotational frequency amplitude and rotational frequency harmonic amplitude exceed the range of the corresponding target parameter threshold; and issuing an early warning of a tooth surface wear fault when the amplitudes corresponding to any two or more frequencies among the meshing frequency amplitude and meshing frequency harmonic amplitude fall within the range of the target parameter threshold.

[0087] Furthermore, after determining that the gear system is in a fault state, the fault type is determined. The specific implementation process is as follows: if the RMS value exceeds the upper limit of the corresponding target parameter threshold and the amplitude of the meshing frequency sideband exceeds the corresponding target parameter threshold range, a tooth breakage fault is warned; if the RMS value exceeds the lower limit of the corresponding target parameter threshold and the amplitude of any two or more frequencies corresponding to the rotational frequency assignment and rotational frequency harmonic assignment exceeds the corresponding target parameter threshold range, a shaft breakage fault is warned; if the amplitude of any two or more frequencies corresponding to the meshing frequency assignment and meshing frequency harmonic assignment exceeds the threshold range, a tooth surface wear fault is warned.

[0088] Step 160: If the running status is faulty, issue a warning message.

[0089] It is understood that the diesel engine online monitoring method provided in this application provides a method that arranges multiple vibration measuring points in the diesel engine gear system and its auxiliary components, and dynamically updates the target parameter threshold of the characteristic parameters corresponding to the vibration data of each vibration measuring point in real time, so as to monitor whether the gear system has a fault in real time and issue an early warning when a fault occurs, thereby realizing online monitoring and early warning of the gear system and improving reliability.

[0090] Figure 5 This is a schematic diagram of the fault early warning and location process provided in the embodiments of this application. For an example, please refer to [link to example]. Figure 5The fault warning and location process for this diesel engine is as follows: First, the current speed, current torque, and vibration signals from various target vibration measurement points are collected, and the vibration signals are filtered to calculate characteristic parameters. Then, the target operating condition range to which the current operating condition belongs is determined based on the current speed and current torque. It is then determined whether there is a threshold within the target operating condition range; if so, the threshold is determined. Otherwise, the relationship between the current characteristic parameters and the threshold is compared (i.e., the relationship between each first target characteristic parameter and its corresponding target parameter threshold is compared). It is then determined whether the trigger warning condition is met; if not, it indicates that the gear system is in normal condition. If the trigger warning condition is met, the location of the warning fault is further determined. If not, a gear system abnormality warning is issued. If yes, the type of warning fault is further determined. If no, a gear system abnormality warning is issued at location ××. If yes, a gear system fault warning is issued at location ××.

[0091] Figure 6 This is a flowchart illustrating the triggering of early warning conditions provided in an embodiment of this application. For example, see [link to example]. Figure 6 The process for triggering an early warning is as follows: Set the rate of change of the characteristic parameter and the time frame; determine whether the rate of change of the characteristic parameter reaches the set value within a certain time period. If it does, an early warning is triggered. If it does not, further determine whether the time exceeding the threshold reaches the set time (the over-limit time is pre-defined). If it does, an early warning is triggered. If it does not, no early warning is triggered.

[0092] Figure 7 This is a schematic diagram illustrating the process for determining the location of a warning fault as provided in an embodiment of this application. For an example, please refer to [link / reference needed]. Figure 7 The process for determining the location of the early warning fault is as follows: First, determine if the characteristic parameters of all vibration measurement points on the idler gears have triggered an early warning. If yes, issue an early warning for a crankshaft or crankshaft gear fault. If no, further determine if the characteristic parameters of the vibration measurement points on the idler gears and the pump meshing with them have triggered an early warning. If yes, issue an early warning for the idler shaft or idler gear fault. If no, further determine if the characteristic parameters of the vibration measurement points on the idler gears and the ×× pump meshing with them have triggered an early warning. If yes, issue an early warning for the shaft or pump gear of the ×× pump. If no, issue an early warning for an abnormality in the gear transmission shaft system.

[0093] Figure 8 This is a schematic flowchart illustrating the process of determining the type of early warning fault provided in an embodiment of this application. See also: Figure 8The process for determining the type of early warning fault is as follows: First, determine if the RMS value exceeds the upper limit of the corresponding target parameter threshold. If the RMS value exceeds the upper limit, further determine if the amplitude of the meshing frequency sideband exceeds the corresponding target parameter threshold range. If the meshing frequency sideband amplitude exceeds the corresponding target parameter threshold range, a gear tooth breakage warning is issued. If the RMS value does not exceed the upper limit, further determine if the RMS value exceeds the lower limit. If the RMS value exceeds the lower limit, further determine if the amplitude of any two or more of the rotational frequency amplitude and octave frequency amplitude exceeds the corresponding target parameter threshold range. If the amplitude of any two or more of the rotational frequency amplitude and octave frequency amplitude exceeds the corresponding target parameter threshold range, a shaft breakage warning is issued. If the RMS value does not exceed the lower limit, further determine if the amplitude of any two or more of the meshing frequency amplitude and octave frequency amplitude exceeds the corresponding target parameter threshold range. If it exceeds, a gear transmission shaft system abnormality warning is issued. If it does not exceed, a tooth surface wear warning is issued.

[0094] Figure 9 This is a schematic diagram of the overall process of the diesel engine online monitoring method provided in the embodiments of this application. For example, see [link to relevant documentation]. Figure 9 The overall implementation process of this diesel engine online monitoring method is as follows: First, vibration measuring point arrangement: This application targets the diesel engine gear system, and collects raw vibration signal data by installing multiple vibration measuring points on the diesel engine gear system and related auxiliary components. Then, characteristic parameter processing: Signals from all vibration measuring points are collected, preprocessed, and the characteristic parameters of each measuring point are calculated. Second, threshold determination: Operating condition intervals are divided by segmenting speed and torque, and the corresponding characteristic parameter thresholds for each operating condition interval are determined. Finally, fault early warning and location: The speed and torque signals of the diesel engine are collected to determine the operating condition interval to which the current operating condition belongs, the relationship between the current characteristic parameters and the threshold is judged, and it is determined whether an early warning condition is triggered. After the early warning condition is triggered, the location of the early warning fault is determined based on the mechanical structural relationship between the diesel engine components monitored by each measuring point; and the type of early warning fault is determined by the category of the characteristic parameters that triggered the early warning.

[0095] For example, this application can realize the monitoring and early warning of diesel engine gear system under all operating conditions, without relying on experience, and realize the early warning and the preliminary location of early warning faults.

[0096] Using this application, the gear transmission shaft systems of certain diesel engines were monitored. The specific steps are as follows: Step 1, Basis Figure 2 The vibration measurement point layout requirements stipulate that nine vibration measurement points are arranged on the diesel engine.

[0097] Step 2: Set the parameters according to Table 2.

[0098] Table 2: Parameter Setting Table

[0099] Step 3: Divide the stable operating range according to Table 1; within the entire diesel engine operating range (speed 0~1000rpm, torque 0~10000N.m), in addition to the set stable operating range, there is a variable operating range. The variable operating range is divided into several grid areas according to the step size of 50r / min speed and 500N.m torque, and each area represents an operating range.

[0100] Step 4: Collect raw vibration data from 9 vibration measurement points and filter them according to the set filtering parameters.

[0101] Step 5: When the diesel engine is running in a certain operating range, calculate and store the characteristic parameters of 9 vibration measuring points every 1 second.

[0102] Step 6: When the cumulative calculation time of characteristic parameters in a single working condition interval reaches the self-learning time, calculate the average value and standard deviation of each characteristic parameter of each vibration measuring point to generate a threshold interval; if it has not been reached, temporarily store the characteristic parameters, and recalculate the characteristic parameters when the working condition is run again until the threshold is generated.

[0103] Step 7: Taking the diesel engine's highest operating condition as an example, the operating condition at this time belongs to the stable operating condition range (1000±20, 10000±200). If the calculated characteristic parameters within this range have not reached 30 minutes, continue the calculation; if they have reached 30 minutes, calculate the average value μ and standard deviation σ of the characteristic parameters within 30 minutes. Taking the RMS value of the idler gear 1 measuring point as an example, the calculated average value is 30g, the standard deviation is 2g, the maximum value is 33g, and the minimum value is 28g. Compare (24, 36) and (23.8, 39.6) to determine that the RMS value is within the threshold range (23.8, 39.6) of the (1000±20, 10000±200) operating condition range.

[0104] Step 8: Run the stable operating range again (1000±20, 10000±200). At this time, the RMS value of the idler gear 1 measuring point is 50g, which lasts for more than 1 minute and exceeds the upper limit of 39.6g by 1.25 times, triggering the warning condition. At the same time, the characteristic parameter of the idler gear 2 measuring point also triggers the warning condition. Warning: crankshaft / crankshaft gear abnormality.

[0105] Step 9: The amplitude of the meshing frequency sideband (fc±if0, i=1, 2, 3) at the idler gear 1 measurement point also exceeds the threshold range, triggering a warning of crankshaft gear tooth breakage.

[0106] Step 10: When the cumulative running time in the stable operating range (1000±20, 10000±200) reaches 20 hours, calculate and store the average value of each characteristic parameter within 5 minutes. Taking the RMS value of the idler gear 1 measuring point as an example, the average value is calculated to be 31g.

[0107] Step 11: When the average value of the characteristic parameters of more than 4 measuring points exceeds the limit of 10% during the 5th calculation of the stable operating condition range (1000±20, 10000±200), the average value of the average value of the 5th calculation is calculated. If the average value of the 5th calculation is less than 5%, the threshold is relearned.

[0108] Step 12: If the rate of change is greater than 5%, a warning message for the gear system status of special attention will be issued, the number of warnings will be increased by 1, and the average calculation period will be shortened to 10 hours.

[0109] Step 13: When the third warning is issued, an abnormal gear system status is detected.

[0110] Figure 10 This is a schematic diagram of the principle structure of an online diesel engine monitoring system provided in the embodiments of this application. On the other hand, this application also provides an online diesel engine monitoring system; please refer to [link to relevant documentation]. Figure 10 The diesel engine online monitoring system 100 includes: an acquisition module 101 for acquiring the current speed and current torque of the diesel engine, as well as the first vibration data of each target vibration measuring point; a first determination module 102 for determining the first target characteristic parameter of each target vibration measuring point based on the first vibration data of each target vibration measuring point; a second determination module 103 for determining the first parameter threshold of each first target characteristic parameter based on the current speed, current torque, and each first target characteristic parameter; a third determination module 104 for determining the target parameter threshold of each first target characteristic parameter based on each first target characteristic parameter, the corresponding first parameter threshold, and a preset threshold update condition; a fourth determination module 105 for determining the operating state of the gear system based on each first target characteristic parameter and the corresponding target parameter threshold; the operating state includes a normal state and a fault state; and an issuance module 106 for issuing a warning message when the operating state is a fault state.

[0111] The technical solution of this application provides an online monitoring system for diesel engines. By arranging multiple vibration measuring points on the diesel engine gear system and its auxiliary components, the system dynamically updates the target parameter threshold of the characteristic parameters corresponding to the vibration data of each vibration measuring point in real time, so as to monitor whether the gear system has a fault in real time and issue an early warning when a fault occurs, thereby realizing online monitoring and early warning of the gear system and improving reliability.

[0112] In some embodiments, the first determining module 102 is further configured to: The first vibration data of each target vibration measuring point is preprocessed to obtain the first target characteristic parameters of each target vibration measuring point.

[0113] In some embodiments, the second determining module 103 is further configured to: Acquire first operating data of the diesel engine within a first operating period; wherein, the first operating data includes the first speed and first torque of the diesel engine, and the second vibration data of each target vibration measuring point; The working condition threshold correspondence is determined based on the first rotation speed, the first torque, the preset rotation speed and torque working condition correspondence, and the second vibration data of each target vibration measuring point. The target operating range is determined based on the current speed, current torque, and the preset speed-torque operating condition correspondence. The first parameter threshold of each first target feature parameter is determined based on the correspondence between the target operating condition range, the operating condition threshold, and each first target feature parameter.

[0114] In some embodiments, the second determining module 103 is further configured to: Based on the correspondence between the first speed, the first torque, and the preset speed-torque operating conditions, the operating conditions of the diesel engine are divided into intervals to obtain multiple operating condition intervals. The second target characteristic parameter of each target vibration measuring point is determined based on the second vibration data of each target vibration measuring point and the first preset calculation period; wherein, the first preset calculation period is the calculation period of the second target characteristic parameter; Under the condition of satisfying the preset number of self-learning, calculate the average value and standard deviation of all second target characteristic parameters of each target vibration measuring point in each working condition interval; The second parameter threshold for each second target characteristic parameter in each working condition interval is determined based on the average value and standard deviation of all second target characteristic parameters of each target vibration measuring point in each working condition interval; The correspondence between the operating condition thresholds is determined based on the second parameter threshold of each second target feature parameter in each operating condition interval and the corresponding operating condition interval.

[0115] In some embodiments, the operating conditions include stable operating conditions and variable operating conditions; the second determining module 103 is further configured to: Under stable operating conditions, the operating conditions are divided according to the range of the first speed, the range of the first torque, and the preset speed-torque correspondence. When the operating conditions are variable, the operating conditions are divided according to the first division step of the first speed and the second division step of the first torque.

[0116] In some embodiments, the second determining module 103 is further configured to: The lower limit of the second parameter threshold is determined based on the average value, standard deviation, and first preset coefficient of all second target characteristic parameters within each working condition interval; The upper limit of the second parameter threshold is determined based on the average value, standard deviation, and second preset coefficient of all second target characteristic parameters within each working condition interval; wherein, the first preset coefficient and the second preset coefficient are the coefficients of the second target characteristic parameter.

[0117] In some embodiments, the third determining module 104 is further configured to: Calculate the average rate of change of each first target feature parameter within a second preset calculation period; If the average rate of change of more than half of the first target characteristic parameters in all target vibration measurement points is less than half of the preset limit, the first parameter threshold is updated to determine the target parameter threshold.

[0118] In some embodiments, the diesel engine online monitoring system 100 further includes: a first judgment module, configured to issue information on the state of the gear train of particular concern when the average change rate of more than half of the first target characteristic parameters in all target vibration measurement points exceeds half of a preset limit, and to record the number of warnings incremented by one.

[0119] In some embodiments, the diesel engine online monitoring system 100 further includes: a second judgment module, used to issue information about abnormal gear system status when the number of warnings exceeds a preset number; If the number of warnings is less than or equal to the preset number, the second preset calculation cycle will be shortened by half.

[0120] In some embodiments, the fourth determining module 105 is further configured to: If the first target feature parameter is within the corresponding target parameter threshold range, the operating state of the gear system is determined to be normal. If the first target feature parameter exceeds the corresponding target parameter threshold range and the duration reaches the first preset duration or the average change rate of the first target feature parameter reaches the preset limit within the second preset duration, the operating state of the gear system is determined to be a fault state, and an early warning is triggered to enter the fault location mode in order to determine the fault location.

[0121] In some embodiments, the gear system includes a camshaft gear, a crankshaft gear, an idler gear, and a belt pump gear; The diesel engine online monitoring system also includes a fifth determination module, used for: When the first target characteristic parameter of the idler gear triggers the warning, it warns that the crankshaft or crankshaft gear has failed. If the first target characteristic parameter of the idler gear triggers an early warning, and the first target characteristic parameters of all the pump gears meshing with the idler gear also trigger an early warning, an early warning will be issued indicating that the shaft of the idler gear or the idler gear itself has failed. If the first target characteristic parameter of the idler gear triggers an early warning, and one of the belt pump gears meshing with the idler gear triggers an early warning due to the first target characteristic parameter of the belt pump gear, an early warning will be issued indicating a fault in the shaft or belt pump gear of the belt pump gear.

[0122] In some embodiments, the time-domain characteristic parameters include effective values; the frequency-domain characteristic parameters include rotational frequency amplitude, rotational frequency harmonic amplitude, meshing frequency amplitude, meshing frequency harmonic amplitude, and meshing frequency sideband amplitude; the diesel engine online monitoring system further includes a sixth determining module, used for: If the effective value exceeds the upper limit of the corresponding target parameter threshold and the amplitude of the meshing frequency sideband exceeds the range of the corresponding target parameter threshold, a warning will be issued for a broken tooth fault. If the effective value exceeds the lower limit of the corresponding target parameter threshold, and if the amplitude of any two or more frequencies among the frequency amplitude and frequency multiplier amplitude exceeds the corresponding target parameter threshold range, an early warning will be issued for a broken shaft fault. If there are any two or more frequencies in the meshing frequency amplitude and the meshing frequency harmonic amplitude that correspond to the target parameter threshold range, an early warning will be issued indicating that a tooth surface wear fault has occurred.

[0123] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0124] The above provides a detailed description of the diesel engine online monitoring method and system provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for online monitoring of a diesel engine, characterized in that, The diesel engine includes a gear train and associated components. Multiple target vibration measuring points are respectively arranged on the gear train and the auxiliary components; the method includes: Obtain the current speed and current torque of the diesel engine, as well as the first vibration data of each of the target vibration measurement points; The first target characteristic parameter of each target vibration measuring point is determined based on the first vibration data of each target vibration measuring point. A first parameter threshold is determined for each first target feature parameter based on the current rotational speed, the current torque, and each first target feature parameter; The target parameter threshold of each first target feature parameter is determined based on each first target feature parameter, the corresponding first parameter threshold, and the preset threshold update condition. The operating state of the gear system is determined based on each of the first target feature parameters and the corresponding target parameter threshold; the operating state includes a normal state and a fault state. And if the operating state is in a fault state, a warning message will be issued.

2. The method according to claim 1, characterized in that, The step of determining the first target characteristic parameter of the target vibration measuring point based on the first vibration data of each target vibration measuring point includes: The first vibration data of each target vibration measuring point is preprocessed to obtain the first target feature parameters of each target vibration measuring point; wherein, the first target feature parameters include time domain feature parameters and frequency domain feature parameters.

3. The method according to claim 1, characterized in that, The step of determining the first parameter threshold for each first target feature parameter based on the current rotational speed, the current torque, and each first target feature parameter includes: Acquire first operating data of the diesel engine within a first operating period; wherein the first operating data includes the first speed and first torque of the diesel engine, and the second vibration data of each of the target vibration measuring points; The working condition threshold correspondence is determined based on the first rotation speed, the first torque, the preset rotation speed and torque working condition correspondence, and the second vibration data of each of the target vibration measuring points. The target operating condition range is determined based on the current speed, the current torque, and the preset speed-torque operating condition correspondence. The first parameter threshold of each first target feature parameter is determined based on the target operating condition range, the corresponding relationship of the operating condition thresholds, and each first target feature parameter.

4. The method according to claim 3, characterized in that, The step of determining the working condition threshold correspondence based on the first rotational speed, the first torque, the preset rotational speed-torque working condition correspondence, and the second vibration data of each of the target vibration measuring points includes: Based on the first speed, the first torque, and the preset speed-torque working condition correspondence, the operating conditions of the diesel engine are divided into intervals to obtain multiple operating condition intervals; The second target characteristic parameter of each target vibration measuring point is determined based on the second vibration data of each target vibration measuring point and the first preset calculation period; wherein, the first preset calculation period is the calculation period of the second target characteristic parameter; Under the condition of satisfying the preset number of self-learning, calculate the average value and standard deviation of all second target characteristic parameters of each target vibration measuring point in each working condition interval; The second parameter threshold for each second target characteristic parameter in each working condition interval is determined based on the average value and standard deviation of all second target characteristic parameters of each target vibration measuring point in each working condition interval; The working condition threshold correspondence is determined based on the second parameter threshold of each second target feature parameter in each working condition interval and the corresponding working condition interval.

5. The method according to claim 4, characterized in that, The operating conditions include stable operating conditions and variable operating conditions; based on the first speed, the first torque, and the preset speed-torque operating condition correspondence, the operating conditions of the diesel fuel are divided into intervals to obtain multiple operating condition intervals, including: When the operating condition is the stable operating condition, the operating condition is divided according to the range of the first speed, the range of the first torque, and the preset speed-torque operating condition correspondence. When the operating condition is the variable operating condition, the operating condition is divided according to the first division step of the first speed and the second division step of the first torque.

6. The method according to claim 4, characterized in that, The step of determining the second parameter threshold for each second target characteristic parameter in each working condition interval based on the average value and standard deviation of all second target characteristic parameters of each target vibration measuring point in each working condition interval includes: The lower limit of the second parameter threshold is determined based on the average value, the standard deviation, and the first preset coefficient of all second target characteristic parameters within each operating condition interval; The upper limit of the second parameter threshold is determined based on the average value, the standard deviation, and the second preset coefficient of all second target feature parameters within each operating condition interval; wherein the first preset coefficient and the second preset coefficient are the coefficients of the second target feature parameter.

7. The method according to claim 1, characterized in that, The step of determining the target parameter threshold for each first target feature parameter based on each first target feature parameter, the corresponding first parameter threshold, and a preset threshold update condition includes: Calculate the average rate of change of each of the first target feature parameters within a second preset calculation period; If, among all the target vibration measurement points, more than half of the average change rates of the first target characteristic parameter are less than half of a preset limit, the first parameter threshold is updated to determine the target parameter threshold.

8. The method according to claim 7, characterized in that, The method further includes: when more than half of the target vibration measurement points have a rate of change of the average value of the first target characteristic parameter exceeding half of a preset limit, issuing a message to focus on the state of the gear system and recording the number of warnings incremented by one.

9. The method according to claim 8, characterized in that, The method further includes: issuing information indicating an abnormal state of the gear system when the number of warnings exceeds a preset number; If the number of warnings is less than or equal to the preset number, the second preset calculation cycle is shortened by half.

10. The method according to claim 2, characterized in that, Determining the operating state of the diesel engine based on each of the first target feature parameters and the corresponding target parameter threshold includes: When the first target feature parameter is within the corresponding target parameter threshold range, the operating state of the gear system is determined to be the normal state; If the first target feature parameter exceeds the corresponding target parameter threshold range and the duration reaches a first preset duration or the average change rate of the first target feature parameter reaches a preset limit within a second preset duration, the operating state of the gear system is determined to be a fault state, and an early warning is triggered to enter the fault location mode to determine the fault location.

11. The method according to claim 10, characterized in that, The gear system includes camshaft gears, crankshaft gears, idler gears, and gears for the pump. The method for determining the location of the fault includes: When the first target characteristic parameter of the idler gear triggers an early warning, an early warning is issued indicating that the crankshaft or the crankshaft gear has malfunctioned. If the first target characteristic parameter of the idler gear triggers an early warning, and the first target characteristic parameter of all the machine-belt pump gears meshing with the idler gear also triggers an early warning, an early warning is issued indicating that the shaft of the idler gear or the idler gear itself has malfunctioned. If the first target characteristic parameter of the idler gear triggers an early warning, and if the first target characteristic parameter of one of the belt pump gears meshing with the idler gear triggers an early warning, an early warning is issued indicating that the shaft of the belt pump gear or the belt pump gear itself has malfunctioned.

12. The method according to claim 10, characterized in that, The time-domain characteristic parameters include effective values; the frequency-domain characteristic parameters include frequency shift amplitude, frequency shift harmonic amplitude, meshing frequency amplitude, meshing frequency harmonic amplitude, and meshing frequency sideband amplitude. The method further includes: If the effective value exceeds the upper limit of the corresponding target parameter threshold and the amplitude of the meshing frequency sideband exceeds the range of the corresponding target parameter threshold, a warning is issued that a tooth breakage fault has occurred. If the effective value exceeds the lower limit of the corresponding target parameter threshold, and if the amplitude of any two or more frequencies among the frequency conversion amplitude and the frequency conversion multiplier amplitude exceeds the corresponding target parameter threshold range, an early warning of shaft breakage fault will be issued. If any two or more frequencies corresponding to the amplitudes of the meshing frequency amplitude and the harmonic amplitude of the meshing frequency fall within the threshold range of the target parameter, an early warning will be issued indicating a tooth surface wear fault.

13. A diesel engine online monitoring system, characterized in that, The diesel engine includes a gear train and associated components. Multiple target vibration measuring points are respectively arranged on the gear train and the auxiliary components; including: The acquisition module is used to acquire the current speed and current torque of the diesel engine, as well as the first vibration data of each of the target vibration measurement points; The first determining module is used to determine the first target characteristic parameter of the target vibration measuring point based on the first vibration data of each target vibration measuring point. The second determining module is used to determine a first parameter threshold for each first target feature parameter based on the current rotation speed, the current torque, and each first target feature parameter. The third determining module is used to determine the target parameter threshold of each first target feature parameter based on each first target feature parameter, the corresponding first parameter threshold, and the preset threshold update condition. The fourth determining module is used to determine the operating state of the gear system based on each of the first target feature parameters and the corresponding target parameter threshold; the operating state includes a normal state and a fault state; The issuing module is used to issue early warning information when the operating state is in a fault state.

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