Method and system for testing lubricating performance of friction pair of engine

Abstract

The invention relates to the technical field of friction pair testing, in particular to a method and system for testing the lubricating performance of an engine friction pair. The method comprises the following steps: simulating reciprocating motion of a friction pair of an engine in a lubricating state by using a friction part of a friction tester, and acquiring data points of the friction part at different moments; according to the moments corresponding to the data points, the friction force data and the temperature data, the multiple data points of the friction part are clustered to obtain multiple clusters, and noise degree values of the clustered data points are determined; determining an abnormal degree value of the target data point according to the noise degree value of the data point in the data space; and taking the reciprocal of the average value of the abnormal degree values of all the correction data points as the lubricating performance parameter value of the friction pair in the lubricating state. According to the technical scheme, a more accurate test result of the lubricating performance of the friction pair can be obtained.

Description

Technical Field

[0001] The present application relates to the technical field of friction pair testing, and in particular to a method and system for testing the lubrication performance of an engine friction pair. Background Art

[0002] The engine friction pair refers to the two components inside the engine that move relative to each other and contact each other. The friction pair generates friction in the process of contact and relative movement. For example, the friction pair composed of the piston and the cylinder wall, the friction pair composed of the crankshaft and the bearing, and the friction pair composed of the camshaft and the valve stem. These friction pairs play a key role in the operation of the engine, but they may also cause wear of the components due to friction, thereby affecting the performance and life of the engine. Therefore, it is necessary to test the lubrication performance of the friction pairs with lubricant added in the engine.

[0003] In order to test the lubrication performance of the friction pair, a Chinese patent application document with publication number CN114459757A provides a method for testing the lubrication performance of a rolling friction pair, including: installing a rolling friction pair specimen between a base and a fixed bracket, connecting the specimen bearing in the rolling friction pair specimen to the output end of the motor assembly through a connecting piece, a force-bearing turntable and a turntable shaft head; adjusting the loading assembly so that the output loading force of the telescopic rod of its force-applying unit is applied to the crossbeam to ensure that the force-applying roller is in contact with the circumference of the force-bearing turntable, and after adding a predetermined amount of grease to the rolling friction pair specimen, clicking a start test button; the motor assembly runs according to a fixed acceleration and deceleration program, the force-applying unit applies pressure according to the force set by the program, and the pressure sensor feedback value is used as a closed-loop condition for pressure regulation to control the force-applying unit, and the loaded load value and speed value as well as the temperature parameters obtained by the temperature sensor are recorded, and the grease squeezed out of the lubrication pair is sampled and analyzed at a certain time interval to obtain the lubrication performance results of the rolling friction pair.

[0004] The distribution of grease at different positions in the lubrication pair may be different, making it difficult for the grease squeezed out of the lubrication pair to accurately represent the lubrication state of the lubrication pair. Therefore, the relevant technology performs sampling and analysis on the grease squeezed out of the lubrication pair, which is difficult to accurately achieve effective testing of the friction pair with grease added. Summary of the invention

[0005] In order to overcome the problem in the related art that it is difficult to accurately and effectively test a friction pair to which grease is added, the present application provides a method and system for testing the lubrication performance of an engine friction pair.

[0006] According to a first aspect of an embodiment of the present application, a method for testing the lubrication performance of an engine friction pair is provided, comprising: using a friction component of a friction tester to simulate the reciprocating motion of the friction pair of the engine under a lubricated state, and obtaining data points of the friction component at different times; the data points include friction force data and temperature data of the friction component at different times; performing three-dimensional clustering on multiple data points of the friction component according to the time, friction force data and temperature data corresponding to the data points to obtain multiple cluster clusters, and determining the noise level value of the data points in the data space of the three-dimensional clusters; adjusting the friction force data or temperature data of the data points according to the noise level value of the data points in the data space to obtain corrected data points, and determining the credibility value of the cluster cluster according to the correlation between the friction force data and the temperature data of the corrected data points in the same cluster cluster; determining the neighborhood size corresponding to the corrected data point according to the credibility value of the cluster cluster to which the corrected data point belongs, so as to determine the abnormality level value of the target data point using the neighborhood size; taking the reciprocal of the average value of the abnormality level values ​​of all corrected data points as the lubrication performance parameter value of the friction pair under a lubricated state, and the lubrication performance parameter value is used to characterize the ability of the friction pair to which lubricant is added to maintain lubrication at different temperatures.

[0007] In this way, by using the friction components of the friction tester to simulate the reciprocating motion of the friction pair of the engine under lubricated conditions, and obtaining the friction force data and temperature data of the friction components at different times, it is possible to simulate the temperature changes of the friction pair of the engine under reciprocating motion, thereby determining the lubrication performance parameter value of the friction pair under lubricated conditions. The lubrication performance parameter value can characterize the ability of the friction pair to which lubricant is added to maintain lubrication at different temperatures. Compared with testing the friction pair by squeezing grease out of the lubrication pair, the friction force data and temperature data can better reflect the actual lubrication condition of the friction pair, thereby obtaining a more accurate test result for the lubrication performance of the friction pair.

[0008] Optionally, determining a noise level value of a data point in a three-dimensional clustering data space includes: ,in, Indicates The noise level value of the a-th data point in the cluster under the m-th monitoring parameter; norm is the normalization function, For the The vertical distance from the a-th data point in the m-th monitoring parameter to the hyperplane corresponding to the m-th monitoring parameter; the hyperplane corresponding to the m-th monitoring parameter is obtained by fitting the time series corresponding to the m-th monitoring parameter in the same cluster; For the The average vertical distance of the other data points in the clusters except the a-th data point to the hyperplane corresponding to the m-th parameter when the m-th monitoring parameter is taken; the monitoring parameter is friction data or temperature data.

[0009] In this way, the average value of the vertical distances from other data points to the hyperplane and the vertical distance from the a-th data point to the hyperplane are compared. The difference between these two vertical distances can reflect the difference between the a-th data point and other data points clustered into the same cluster. The numerical value of the noise data point is sporadic, so the obtained noise degree value can effectively characterize the probability that the data point belongs to the noise data point.

[0010] Optionally, according to the noise level value of the data point in the data space, the friction data or the temperature data of the data point is adjusted to obtain a corrected data point, including: , For the The value of the mth monitoring parameter of the ath data point in the cluster after adjustment; For the The value of the mth monitoring parameter of the ath data point in the cluster before adjustment, For the The noise level value of the a-th data point in the cluster under the m-th monitoring parameter, For the The value of the mth monitoring parameter of the a-1th data point in the cluster before adjustment; the monitoring parameter is friction data or temperature data.

[0011] In this way, the adjustment of the monitoring parameters of the data points in the data space is carried out based on the noise level value of the monitoring parameters of the data points and the changes in the monitoring parameters of the friction components at adjacent moments. A larger adjustment amount can be used for the monitoring parameters of the data points when the probability that the monitoring parameters of the data points are affected by noise is greater, or a smaller adjustment amount can be used for the monitoring parameters of the data points when the monitoring parameters of the data points remain stable, thereby ensuring the accuracy of the monitoring parameters of the data points after adjustment.

[0012] Optionally, the credibility value of the cluster is determined according to the correlation between the friction data and the temperature data of the corrected data points in the same cluster, including: ,in, For the The credibility value of a cluster, exp is an exponential function with a natural constant as the base, For the The friction data of the corrected data points in the clusters are arranged in time order. For the The temperature data of the corrected data points in the clusters are a sequence composed of time order, It means taking the covariance between two series.

[0013] In this way, the credibility value of the cluster is determined according to the correlation between the friction data and the temperature data of the corrected data points in the same cluster, and a higher credibility value can be assigned to the cluster whose friction data is more stable at different temperatures, so as to evaluate the ability of the friction pair with lubricating oil added to maintain lubrication at different temperatures.

[0014] Optionally, determining the size of the neighborhood corresponding to the corrected data point according to the credibility value of the cluster to which the corrected data point belongs includes: ,in, is the neighborhood size corresponding to the rth corrected data point, To preset the neighborhood size, is the credibility value of the cluster to which the rth corrected data point belongs, is the maximum timestamp of all the corrected data points of the cluster to which the rth corrected data point belongs. is the timestamp of the rth corrected data point, Indicates rounding up.

[0015] In this way, the neighborhood size matching the corrected data point can be adaptively set based on the preset neighborhood size according to the credibility value of the cluster to which the corrected data point belongs, so as to take into account both the calculation efficiency and accuracy of the abnormality degree value of the corrected data point.

[0016] Optionally, the abnormality degree value of the target data point is determined using the neighborhood size, including: determining multiple reference data points in the data space that are within the range corresponding to the neighborhood size of the target data point, and determining the abnormality degree value of the target data point using the target data point, the ABOD anomaly detection algorithm and the multiple reference data points; wherein the abnormality degree value is used to characterize the degree of discreteness between the target data point and the reference data point.

[0017] Optionally, the friction component of the friction tester is used to simulate the reciprocating motion of the friction pair of the engine under lubricated state, including: adding a preset amount of lubricant to the friction component, and controlling the friction component to reciprocate; the material of the friction component is the same as the material of the friction pair of the engine, and the structure of the friction component is the same as the structure of the friction pair of the engine.

[0018] According to a second aspect of an embodiment of the present application, a system for testing the lubrication performance of an engine friction pair is provided, comprising: a processor and a memory, wherein the memory stores computer program instructions, and when the computer program instructions are executed by the processor, the steps of the method for testing the lubrication performance of an engine friction pair provided in the first aspect of the present application are implemented.

[0019] The technical solution provided by the embodiments of the present application may include the following beneficial effects: using the friction components of the friction tester to simulate the reciprocating motion of the friction pair of the engine under a lubricated state, and obtaining the friction force data and temperature data of the friction components at different times, it is possible to simulate the temperature changes that occur in the friction pair of the engine under the reciprocating motion, thereby determining the lubrication performance parameter value of the friction pair under the lubricated state, and the lubrication performance parameter value can characterize the ability of the friction pair to which lubricant is added to maintain lubrication at different temperatures. Compared with testing the friction pair by squeezing grease out of the lubrication pair, the friction force data and temperature data can better reflect the actual lubrication condition of the friction pair, thereby obtaining a more accurate test result for the lubrication performance of the friction pair.

[0020] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0022] Figure 1 is a flow chart showing a method for testing lubrication performance of an engine friction pair according to an exemplary embodiment; Figure 2 It is a schematic structural diagram of a system for testing the lubrication performance of an engine friction pair according to an exemplary embodiment. DETAILED DESCRIPTION

[0023] Here, exemplary embodiments are described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application.

[0024] First, the application scenario of the embodiment of the present application is briefly introduced. In the application scenario of the present application, a friction tester can be used to simulate the motion state of the friction pair to be tested, and the lubrication performance of the friction pair with lubricant added can be tested by measuring the dosage of lubricant overflowed from the friction pair.

[0025] However, it is difficult to accurately reflect the lubrication state of the friction pair to which the lubricant is added through the amount of the overflowed lubricant. Therefore, it is difficult for the related technology to accurately implement the test of the lubrication performance of the friction pair to which the lubricant is added.

[0026] In view of the above technical problems, the present application provides a method and system for testing the lubrication performance of an engine friction pair. Figure 1 is a flow chart showing a method for testing the lubrication performance of an engine friction pair according to an exemplary embodiment. Figure 1 As shown, the method includes the following steps.

[0027] In step S101, the friction component of the friction tester is used to simulate the reciprocating motion of the friction pair of the engine in a lubricated state, and data points of the friction component at different times are obtained.

[0028] The data points include friction force data and temperature data of the friction component at different times, and the same data point includes friction force data and temperature data of the friction component at the same time.

[0029] The friction component may include two sub-components that contact each other and reciprocate. The contact surfaces of the two sub-components may be coated with lubricant. The two sub-components may be used to simulate the reciprocating motion of the friction pair of the engine under a lubricated state. By acquiring the friction force data and temperature data of the two sub-components during the reciprocating motion, the movement process of the friction component can be effectively monitored.

[0030] As the duration of the reciprocating motion of two sub-components in contact with each other increases, the temperature of the contact surface of the two sub-components may rise. By obtaining the friction force data and temperature data of the two sub-components during the reciprocating motion, it can be reflected that the friction between the two sub-components is affected by the temperature rise caused by friction.

[0031] The temperature sensor may be installed near the contact surface of the two sub-components of the friction assembly, or may be installed on the contact surface of the sub-components. The temperature sensor may be, for example, a thermocouple temperature sensor or an infrared temperature sensor.

[0032] Multiple mechanical sensors can be set at different positions in the friction tester to determine the friction data between the two sub-components of the friction component based on the mechanical monitoring data obtained by the mechanical sensors. For example, the power applied to the friction component during movement, the acceleration information of the friction component, and the angular velocity information can be obtained by multiple mechanical sensors to determine the friction data between the two sub-components of the friction component. The embodiment of the present application does not limit the method for obtaining the friction data of the friction component.

[0033] A friction component with the same material and structure as the friction pair to be tested in the engine can be used to simulate the lubrication condition of the friction pair added with lubricant during the reciprocating motion of the engine.

[0034] The friction pair to be tested in the engine may be, for example, the friction pair between the piston and the cylinder wall, or the friction pair to be tested in the engine may be, for example, the friction pair between the camshaft and the valve stem end. The embodiments of the present application do not limit the specific friction pair tested.

[0035] In one embodiment, a friction component of a friction tester is used to simulate the reciprocating motion of a friction pair of an engine under a lubricated state, including: adding a preset amount of lubricant to the friction component, and controlling the friction component to reciprocate; the material of the friction component is the same as the material of the friction pair of the engine, and the structure of the friction component is the same as the structure of the friction pair of the engine.

[0036] The lubricant added to the friction component may be lubricating oil or grease, for example, when the engine is a diesel engine, the lubricant may be diesel engine oil; when the engine is a gasoline engine, the lubricant may be gasoline engine oil.

[0037] The preset dosage of lubricant can be determined according to the size of the contact area of ​​the friction pair and the frequency of the reciprocating motion, or according to the historical dosage of lubricant added in the past, which will not be elaborated here.

[0038] By adding a preset amount of lubricant, it is possible to test the effect of different amounts of lubricant on the lubrication effect of the friction pair, thereby determining the optimal amount of lubricant and reducing lubricant waste while preventing wear caused by insufficient lubrication.

[0039] The friction tester's friction components are used to simulate this process. The material and structure of the friction components are the same as those of the engine's friction pair. A preset amount of lubricant is added to restore the conditions of the engine's friction pair in a real working environment to the greatest extent possible, avoiding tests directly on the engine and reducing the cost of testing the engine's friction pair.

[0040] In step S102, three-dimensional clustering is performed on multiple data points of the friction component according to the time, friction data and temperature data corresponding to the data points to obtain multiple clusters, and the noise level value of the data points in the three-dimensional clustering data space is determined.

[0041] Since the timestamp information corresponding to the data points is different, and the friction data and temperature data of the friction parts at different times may be different, the time, friction data and temperature data can be used as three dimensions respectively, and three-dimensional clustering is performed on multiple data points of the friction parts to obtain multiple cluster clusters; the three dimensions of the data space correspond to the time, friction data and temperature data respectively.

[0042] Three-dimensional clustering of multiple data points of friction parts is performed to obtain multiple cluster clusters, which can be achieved through clustering algorithms such as spectral clustering algorithm, hierarchical clustering algorithm, density-based clustering algorithm and iterative self-organizing clustering algorithm.

[0043] Among the multiple data points obtained from the friction component, there may be some noisy data points affected by noise. Since the influence of noise is random, the difference between the noise data points affected by noise and other data points not affected by noise is large, and such difference is difficult to effectively characterize the actual abnormality of the data point itself. Therefore, the noise degree value of the data point can be determined by comparing the data points to avoid the data point being affected by possible noise.

[0044] In one embodiment, determining the noise level value of a data point in a three-dimensional clustered data space includes: ,in, Indicates The noise level value of the a-th data point in the cluster under the m-th monitoring parameter; norm is the normalization function, For the The vertical distance from the a-th data point in the m-th monitoring parameter to the hyperplane corresponding to the m-th monitoring parameter; the hyperplane corresponding to the m-th monitoring parameter is obtained by fitting the time series corresponding to the m-th monitoring parameter in the same cluster; For the The average vertical distance of the other data points except the a-th data point in the clusters to the hyperplane corresponding to the m-th parameter when the m-th monitoring parameter is taken; the monitoring parameter is friction data or temperature data.

[0045] The hyperplane corresponding to the monitoring parameter can be obtained by fitting the values ​​of data points at different times in the same cluster under the monitoring parameter. For example, when the monitoring parameter is friction data, the friction data of different data points in the same cluster can be fitted by least squares to obtain the hyperplane corresponding to the friction data of the same cluster.

[0046] By referring to the process of obtaining the hyperplane corresponding to the friction data of the same cluster, the hyperplane corresponding to the temperature data of the same cluster can be obtained, so as to evaluate the performance of the data points in the same cluster on the temperature data.

[0047] For the temperature data of a data point in the cluster, the vertical distance from the temperature data of the data point to the hyperplane corresponding to the friction data of the cluster can reflect the difference between the temperature data of the data point and the fitted hyperplane.

[0048] Since the hyperplane corresponding to the temperature data is obtained by fitting the temperature data of the data points in the cluster, the hyperplane corresponding to the temperature data can characterize the corresponding relationship between the temperature data of the data points in the cluster and the time. Therefore, the vertical distance from the temperature data of the data point to the hyperplane of the friction data corresponding to the cluster can reflect the difference between the temperature data of the data point and the overall change of the temperature data in the cluster.

[0049] The normalization function norm is used to normalize the values ​​to be normalized to the range of 0 to 1, so as to perform calculations or comparisons between the values.

[0050] In this way, the average value of the vertical distances from other data points to the hyperplane and the vertical distance from the a-th data point to the hyperplane are compared. The difference between these two vertical distances can reflect the difference between the a-th data point and other data points clustered into the same cluster. The numerical value of the noise data point is sporadic, so the obtained noise degree value can effectively characterize the probability that the data point belongs to the noise data point.

[0051] When analyzing the noise level value of the data points of the friction components, the information of the three dimensions of time information, friction force data and temperature data can be combined to more comprehensively observe the noise performance of the data points of the friction pair to determine whether the data points at a certain moment are affected by noise.

[0052] In step S103, according to the noise level value of the data point in the data space, the friction data or temperature data of the data point is adjusted to obtain a corrected data point, and according to the correlation between the friction data and the temperature data of the corrected data point in the same cluster, the credibility value of the cluster is determined.

[0053] The noise level of a data point reflects the degree of deviation of the data point relative to other data points in the cluster. In an ideal clustering situation, the data points in the cluster should have high similarity and consistency, that is, the noise level is low.

[0054] When the noise level of a data point is high, it means that the friction data or temperature data of the data point may be different from other data points in the cluster due to measurement error, external interference or its own particularity.

[0055] Therefore, it is necessary to adjust the friction data or temperature data of the data point according to the noise level value of the data point. For example, the friction data of the data point can be adjusted according to the noise level value of the data point on the friction data, or the temperature data of the data point can be adjusted according to the noise level value of the data point on the temperature data.

[0056] And because the number of noise data points is smaller than the number of non-noise data points, the data points in the same cluster obtained after clustering already have certain similarities. In order to avoid the influence of the adjustment process on the overall clustering results of non-noise data points, the position of the data points in the data space can be kept unchanged before and after the adjustment.

[0057] In one embodiment, according to the noise level value of the data point in the data space, adjusting the friction data or temperature data of the data point to obtain the corrected data point includes: , For the The value of the mth monitoring parameter of the ath data point in the cluster after adjustment; For the The value of the mth monitoring parameter of the ath data point in the cluster before adjustment, For the The noise level value of the a-th data point in the cluster under the m-th monitoring parameter, For the The value of the mth monitoring parameter of the a-1th data point in the cluster before adjustment; the monitoring parameter is friction data or temperature data.

[0058] In the calculation formula for the value of the monitoring parameter of the data point after adjustment, the greater the noise level value of the monitoring parameter of the data point before adjustment, the greater the adjustment amount of the value of the monitoring parameter of the data point before adjustment; or, the smaller the noise level value of the monitoring parameter of the data point before adjustment, the smaller the adjustment amount of the value of the monitoring parameter of the data point before adjustment.

[0059] Furthermore, since the existence of noise data points is sporadic, when a data point is affected by noise and has a higher noise level value, the probability that data points at adjacent moments are affected by noise at the same time is low, so that the data point at the previous moment of the data point affected by noise can provide a better reference for the adjustment of the data point affected by noise.

[0060] When the friction force data of the friction component changes little at adjacent moments, or when the temperature data of the friction component changes little at adjacent moments, the lubrication performance of the friction component can maintain good stability, and the monitoring parameters of the data points are less likely to be affected by noise. Therefore, a smaller adjustment amount can be used for the values ​​of the monitoring parameters of the data points.

[0061] In this way, the adjustment of the monitoring parameters of the data points in the data space is carried out based on the noise level value of the monitoring parameters of the data points and the changes in the monitoring parameters of the friction components at adjacent moments. A larger adjustment amount can be used for the monitoring parameters of the data points when the probability that the monitoring parameters of the data points are affected by noise is greater, or a smaller adjustment amount can be used for the monitoring parameters of the data points when the monitoring parameters of the data points remain stable, thereby ensuring the accuracy of the monitoring parameters of the data points after adjustment.

[0062] In one embodiment, determining the credibility value of a cluster according to the correlation between the friction data and the temperature data of the corrected data points in the same cluster includes: ,in, For the The credibility value of a cluster, exp is an exponential function with a natural constant as the base, For the The friction data of the corrected data points in the clusters are arranged in time order. For the The temperature data of the corrected data points in the clusters are a sequence composed of time order, It means taking the covariance between two series.

[0063] In the usage scenario of the embodiment of the present application, the stronger the ability of the friction pair with lubricant added in the engine to maintain lubrication at different temperatures, that is, the better the stability of the lubrication performance of the friction pair with lubricant added in the engine, the greater the lubrication performance parameter of the friction pair with lubricant added.

[0064] On the contrary, if the lubricating performance of the friction pair with lubricant added in the engine decreases significantly with the increase of temperature, making it difficult for the friction pair with lubricant added to maintain its lubricating ability after the temperature rises, it means that the friction pair with lubricant added is difficult to meet the requirements of different operating temperatures, and the lubricating performance parameters of the friction pair with lubricant added are smaller.

[0065] By adjusting the monitoring parameters of the data points in the clusters that may be affected by noise, for multiple data points clustered into the same cluster in the data space, different data points are closer in time, and the friction data or temperature data of different data points in the same cluster are closer.

[0066] For the sequence of friction data of the corrected data points in the cluster clusters composed in chronological order and the sequence of corrected data points in the cluster clusters composed in chronological order, the larger the value of the covariance between the two sequences is, the greater the influence of temperature on the friction force of the friction pair with lubricant added under the lubricating effect of the lubricant, and the friction pair with lubricant added may find it difficult to maintain good lubrication performance at different temperatures.

[0067] Since a larger value of the covariance indicates that it is more difficult for the friction pair with the lubricant added to maintain good lubrication performance at different temperatures, a lower credibility value may be assigned to the corresponding cluster with a larger covariance.

[0068] The covariance between the two sequences ranges from -1 to 1. Due to the existence of the 1 / 2 term in the credibility value of the clustering cluster, the exponential term of the exponential function in the credibility value of the clustering cluster can be between -1 and 0. Therefore, after being processed by the exponential function with a natural constant as the base, the credibility value obtained is a positive number less than 1, which is convenient for comparison or calculation between parameters.

[0069] In this way, the credibility value of the cluster is determined according to the correlation between the friction data and the temperature data of the corrected data points in the same cluster, and a higher credibility value can be assigned to the cluster whose friction data is more stable at different temperatures, so as to evaluate the ability of the friction pair with lubricating oil added to maintain lubrication at different temperatures.

[0070] In step S104, the neighborhood size corresponding to the corrected data point is determined according to the credibility value of the cluster to which the corrected data point belongs, so as to determine the abnormality value of the target data point by using the neighborhood size.

[0071] After adjusting the friction data or temperature data of data points that may be affected by noise, the corrected data points in the cluster have avoided possible noise data points. The credibility value of the cluster to which the corrected data points belong can reflect the credibility of the cluster as a whole. For corrected data points with different credibility values, matching neighborhood sizes can be adaptively adopted.

[0072] For example, for a corrected data point with a larger credibility value of the cluster to which it belongs, the degree of abnormality of the corrected data point can be determined by comparing it with a smaller number of neighboring data points; and for a corrected data point with a smaller credibility value of the cluster to which it belongs, the degree of abnormality of the corrected data point can be determined by comparing it with a larger number of neighboring data points; wherein the degree of abnormality is used to characterize the degree of discreteness between the target data point and the reference data point.

[0073] In one embodiment, determining the size of the neighborhood corresponding to the revised data point according to the credibility value of the cluster to which the revised data point belongs includes: ,in, is the neighborhood size corresponding to the rth corrected data point, To preset the neighborhood size, is the credibility value of the cluster to which the rth corrected data point belongs, is the maximum timestamp of all the corrected data points of the cluster to which the rth corrected data point belongs. is the timestamp of the rth corrected data point, Indicates rounding up.

[0074] In the calculation formula of the neighborhood size corresponding to the corrected data point, the larger the credibility value of the cluster to which the corrected data point belongs, the greater the stability of the friction data of the friction component at the time of the corrected data point, and a smaller neighborhood size can be used for the corrected data point.

[0075] On the contrary, the smaller the credibility value of the cluster to which the corrected data point belongs, the less stable the friction data of the friction component is at the moment of the corrected data point. A larger neighborhood size can be used for the corrected data point, and the abnormality value of the corrected data point can be further determined by comparing it with a larger number of neighboring data points.

[0076] A larger timestamp corresponds to a moment closer to the current moment. For example, the timestamp of the current moment is greater than the timestamp of the moment before the current moment. The smaller the difference between the largest timestamp among all the corrected data points of the cluster to which the corrected data point belongs and the timestamp of the rth corrected data point, the closer the time of the corrected data point is to the latest time. The size of the neighborhood corresponding to the corrected data point can be increased to further determine the abnormality value of the corrected data point.

[0077] In the calculation formula of the neighborhood size corresponding to the corrected data point, the 0.01 in the denominator can avoid division by zero during calculation, thereby ensuring the stability of the calculation process of the formula; the preset neighborhood size can be set according to actual needs, for example, the preset neighborhood size can be set to an integer between 5 and 8.

[0078] In this way, the neighborhood size matching the corrected data point can be adaptively set based on the preset neighborhood size according to the credibility value of the cluster to which the corrected data point belongs, so as to take into account both the calculation efficiency and accuracy of the abnormality degree value of the corrected data point.

[0079] In one embodiment, the abnormality degree value of the target data point is determined using the neighborhood size, including: determining multiple reference data points in the data space that are within the range corresponding to the neighborhood size of the target data point, and determining the abnormality degree value of the target data point using the target data point, the ABOD anomaly detection algorithm, and the multiple reference data points; wherein the abnormality degree value is used to characterize the degree of discreteness between the target data point and the reference data point.

[0080] For example, the target data point can be any one of the multiple corrected data points in the data space. If the neighborhood size corresponding to the target data point is 8, the target neighborhood range corresponding to the neighborhood size equal to 8 can be determined, and other corrected data points within the target neighborhood range of the target data point can be used as reference data points of the target data point.

[0081] In the ABOD (Angle-Based Outlier Detection) algorithm, the degree of abnormality corresponding to the target data point can be determined according to the positional relationship between the target data point and multiple reference data points; the more dispersed the positional relationship between the target data point and multiple reference data points, the greater the degree of abnormality corresponding to the target data point, indicating that the degree of outlier of the friction force data of the friction pair at the moment corresponding to the target data point is greater.

[0082] Since the friction component of the friction tester is used to simulate the reciprocating operation of the friction pair of the engine, and lubricant is added to the friction component, when the friction component reciprocates under the action of the lubricant, the greater the degree of outlier of the friction force data of the friction pair at the moment corresponding to the target data point, it means that the friction force stability of the friction force data of the friction pair at the moment or time period corresponding to the target data point is low, making it difficult for the friction pair added with lubricating oil to meet the lubrication requirements at different temperatures; or, the added lubricating oil is difficult to meet the requirement of keeping the friction pair lubricated at different temperatures.

[0083] In step S105, the reciprocal of the average value of the abnormality degree values ​​of all the corrected data points is used as the lubrication performance parameter value of the friction pair in the lubrication state.

[0084] The lubrication performance parameter value is used to characterize the ability of the friction pair with added lubricant to maintain lubrication at different temperatures; the larger the lubrication performance parameter value of the friction pair in the lubricated state, the stronger the ability of the friction pair with added lubricant to maintain lubrication at different temperatures, and the more the friction pair with added lubricant can adapt to the need to maintain lubrication at different temperatures.

[0085] On the contrary, the smaller the lubrication performance parameter value of the friction pair in the lubricated state, the weaker the ability of the friction pair with added lubricant to maintain lubrication at different temperatures, and the more difficult it is for the friction pair with added lubricant to adapt to the need to maintain lubrication at different temperatures.

[0086] The smaller the average value of the abnormality degree of all corrected data points is, the stronger the overall stability of the lubrication performance of the friction pair with added lubricant at different temperatures is, and the more the friction pair with added lubricant can adapt to the need to maintain lubrication at different temperatures.

[0087] A method for testing the lubrication performance of an engine friction pair provided in an embodiment of the present application utilizes the friction components of a friction tester to simulate the reciprocating motion of the engine's friction pair under a lubricated state, and obtains friction force data and temperature data of the friction components at different times. This can simulate the temperature changes of the engine's friction pair under reciprocating motion, thereby determining the lubrication performance parameter value of the friction pair under a lubricated state. The lubrication performance parameter value can characterize the ability of the friction pair to which lubricant is added to maintain lubrication at different temperatures. Compared with testing the friction pair by squeezing grease out of the lubrication pair, the friction force data and temperature data can better reflect the actual lubrication condition of the friction pair, thereby obtaining a more accurate test result for the lubrication performance of the friction pair.

[0088] Figure 2 FIG. 1 is a schematic diagram of a structure of a testing system 1000 for lubrication performance of a friction pair of an engine according to an exemplary embodiment. Figure 2 The engine friction pair lubrication performance testing system 1000 includes: a processor 1100 and a memory 1200, wherein the memory 1200 stores computer program instructions, and when the computer program instructions are executed by the processor 1100, all or part of the steps of the engine friction pair lubrication performance testing method in the present application are implemented.

[0089] It should be understood that the features of some embodiments of the various applications described herein may be combined with each other, unless specifically stated otherwise.

[0090] Although terms such as "first", "second", and "third" may be used herein to describe various components, parts, regions, layers, or sections, these components, parts, regions, layers, or sections are not limited to these terms. Instead, these terms are only used to distinguish one component, part, region, layer, or section from another component, part, region, layer, or section. Therefore, without departing from the teachings of the examples described herein, the first component, part, region, layer, or section mentioned in the examples may also be referred to as the second component, part, region, layer, or section.

[0091] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description herein, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0092] In addition, the word "exemplary" is used herein to mean serving as an example, instance, or diagram. Any aspect or design described herein as "exemplary" is not necessarily to be understood as being advantageous over other aspects or designs. Instead, the use of the word exemplary is intended to present concepts in a concrete manner. As used herein, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or".

[0093] Likewise, although the present application has been shown and described with respect to one or more implementations, equivalent variations and modifications will occur to those skilled in the art upon reading and understanding this specification and the accompanying drawings. With particular regard to the various functions performed by the components (e.g., elements, resources, etc.) described above, unless otherwise noted, the terms used to describe such components are intended to correspond to any component (functionally equivalent) that performs the specific functions of the described components, even if not structurally equivalent to the disclosed structures.

[0094] Additionally, while particular features of the present application may have been disclosed with respect to only one of several implementations, such features may be combined with one or more other features of other implementations as may be desired and advantageous for any given or particular application.

[0095] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary technical means in the art that are not disclosed in the present application, and the specification and embodiments are only considered as exemplary.

[0096] It will be appreciated that the present application is not limited to the exact construction that has been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof.

Claims

1. A method for testing the lubrication performance of an engine friction pair, characterized in that: include: The friction components of the friction tester are used to simulate the reciprocating motion of the friction pair of the engine under lubrication, and the data points of the friction components at different times are obtained; The data points include friction force data and temperature data of the friction component at different times; According to the time, friction force data and temperature data corresponding to the data points, three-dimensional clustering is performed on multiple data points of the friction component to obtain multiple cluster clusters, and the noise level value of the data points in the data space of the three-dimensional clustering is determined; According to the noise level value of the data point in the data space, the friction data or the temperature data of the data point is adjusted to obtain a corrected data point, and according to the correlation between the friction data and the temperature data of the corrected data point in the same cluster, the credibility value of the cluster is determined; Determine the size of the neighborhood corresponding to the corrected data point according to the credibility value of the cluster to which the corrected data point belongs, so as to determine the abnormality value of the target data point by using the neighborhood size; The reciprocal of the average value of the abnormality degree values ​​of all corrected data points is taken as the lubrication performance parameter value of the friction pair in the lubricated state, and the lubrication performance parameter value is used to characterize the ability of the friction pair to which lubricant is added to maintain lubrication at different temperatures.

2. The method for testing the lubrication performance of an engine friction pair according to claim 1, characterized in that: Determine the noise level of data points in the data space of three-dimensional clustering, including: ,in, Indicates The noise level value of the a-th data point in the cluster under the m-th monitoring parameter; norm is the normalization function, For the The vertical distance from the a-th data point in the m-th monitoring parameter to the hyperplane corresponding to the m-th monitoring parameter; the hyperplane corresponding to the m-th monitoring parameter is obtained by fitting the time series corresponding to the m-th monitoring parameter in the same cluster; For the The average vertical distance of the other data points except the a-th data point in the clusters to the hyperplane corresponding to the m-th parameter when the m-th monitoring parameter is taken; the monitoring parameter is friction data or temperature data.

3. The method for testing the lubrication performance of an engine friction pair according to claim 1, characterized in that: According to the noise level value of the data point in the data space, the friction data or temperature data of the data point is adjusted to obtain the corrected data point, including: , For the The value of the mth monitoring parameter of the ath data point in the cluster after adjustment; For the The value of the mth monitoring parameter of the ath data point in the cluster before adjustment, For the The noise level value of the a-th data point in the cluster under the m-th monitoring parameter, For the The value of the mth monitoring parameter of the a-1th data point in the cluster before adjustment; the monitoring parameter is friction data or temperature data.

4. The method for testing the lubrication performance of an engine friction pair according to claim 1, characterized in that: According to the correlation between the friction data and the temperature data of the corrected data points in the same cluster, the credibility value of the cluster is determined, including: ,in, For the The credibility value of a cluster, exp is an exponential function with a natural constant as the base, For the The friction data of the corrected data points in the clusters are arranged in time order. For the The temperature data of the corrected data points in the clusters are a sequence composed of time order, It means taking the covariance between two series.

5. The method for testing the lubrication performance of an engine friction pair according to claim 1, characterized in that: According to the credibility value of the cluster to which the corrected data point belongs, the size of the neighborhood corresponding to the corrected data point is determined, including: ,in, is the neighborhood size corresponding to the rth corrected data point, To preset the neighborhood size, is the credibility value of the cluster to which the rth corrected data point belongs, is the maximum timestamp of all the corrected data points of the cluster to which the rth corrected data point belongs. is the timestamp of the rth corrected data point, Indicates rounding up.

6. The method for testing the lubrication performance of an engine friction pair according to claim 1, characterized in that: Determining the abnormality value of the target data point by using the neighborhood size includes: Determine multiple reference data points in the data space that are within the range corresponding to the neighborhood size of the target data point, and use the target data point, the ABOD anomaly detection algorithm and the multiple reference data points to determine the abnormality degree value of the target data point; wherein the abnormality degree value is used to characterize the degree of discreteness between the target data point and the reference data point.

7. The method for testing the lubrication performance of engine friction pairs according to claim 1, characterized in that: The friction components of the friction tester are used to simulate the reciprocating motion of the friction pair of the engine under lubrication, including: A preset amount of lubricant is added to the friction component, and the friction component is controlled to perform reciprocating motion; the material of the friction component is the same as the material of the friction pair of the engine, and the structure of the friction component is the same as the structure of the friction pair of the engine.

8. A testing system for lubrication performance of engine friction pair, characterized in that: include: A processor and a memory, wherein the memory stores computer program instructions, and when the computer program instructions are executed by the processor, a method for testing the lubrication performance of an engine friction pair according to any one of claims 1 to 7 is implemented.

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