Diagnosis method and diagnosis device

Abstract

A diagnosis method according to the present disclosure is a diagnosis method for diagnosing deterioration of lubricating oil. The lubricating oil contains a phenolic antioxidant. The diagnosis method comprises: detecting the color of the lubricating oil with a color sensor, and thus acquiring RGB data from the color sensor; and diagnosing deterioration of the lubricating oil on the basis of B data of the RGB data.

Description

Diagnostic method and diagnostic device

[0001] The present invention relates to a diagnostic method and a diagnostic device.

[0002] Patent Document 1 describes a method for diagnosing deterioration of lubricating oil using a sensor.

[0003] Japanese Patent Application Laid-Open No. 2019-78718

[0004] Patent Document 1 describes that lubricating oils contain various additives, including load-bearing additives such as oiliness agents, anti-wear agents, and extreme-pressure additives (extreme-pressure agents), as well as antioxidants and antifoaming agents. Patent Document 1 also describes estimating the concentration of additives contained in lubricating oil based on the B value in the chromaticity data. However, Patent Document 1 does not identify compounds suitable for deterioration diagnosis based on the B value.

[0005] The present invention aims to diagnose the deterioration of lubricating oil based on B data by utilizing the characteristics of phenolic antioxidants.

[0006] The main invention for achieving the above object is a diagnostic method for diagnosing deterioration of a lubricating oil, wherein the lubricating oil contains a phenolic antioxidant, the color of the lubricating oil is detected by a color sensor, RGB data is obtained from the color sensor, and the deterioration of the lubricating oil is diagnosed based on the B data of the RGB data.

[0007] Other features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[0008] According to the present invention, the characteristics of the phenolic antioxidant can be utilized to diagnose the deterioration of the lubricating oil based on the B data.

[0009] Figure 1 is a graph showing the time-dependent change in the detection results of a color sensor and the time-dependent change in the residual rate of antioxidants contained in lubricating oil. Figure 2 is a table showing the main absorption wavelengths of oxidation products, including DBPC. Figure 3 is an explanatory diagram of the DBPC oxidation process. Figures 4A to 4C are chromatograms obtained by a UV-Vis detector. Figure 5 is a graph showing the spectral detection results of a lubricating oil sample taken at timing B in Figure 1. Figure 6A is a chromatogram of the sample taken at timing B, and Figure 6B is a chromatogram of a TBSQ standard reagent. Figure 7A is a mass chromatogram of the sample taken at timing B, and Figure 7B is a mass chromatogram of a TBSQ standard reagent. Figure 8A is a mass spectrum of the sample taken at timing B, and Figure 8B is a mass spectrum of a TBSQ standard reagent. Figure 9 is a graph showing the time-dependent change in the detection results of a color sensor for a different lubricating oil and the time-dependent change in the residual rate of antioxidants contained in the lubricating oil. Figure 10 is an explanatory diagram of a diagnostic system 100. 11A and 11B are explanatory diagrams of the sensor unit 20. FIG. 12 is an explanatory diagram of lubricant profile information. FIG. 13 is an explanatory diagram of an example of the detection result database 422. FIG. 14 is a flow diagram of the diagnosis process. FIG. 15 is an explanatory diagram of the replacement time t1 and the remaining period Pr.

[0010] <Cross-reference to related applications> This application claims priority based on Japanese Patent Application No. 2024-078199, filed on May 13, 2024, and incorporates the contents of that application by reference. At least the following aspects will become apparent from the description of this specification and the accompanying drawings.

[0011] Aspect 1 is a diagnostic method for diagnosing deterioration of a lubricating oil, the lubricating oil containing a phenolic antioxidant, the method detecting the color of the lubricating oil with a color sensor to obtain RGB data from the color sensor, and diagnosing deterioration of the lubricating oil based on B data of the RGB data. According to the diagnostic method of aspect 1, deterioration of the lubricating oil can be diagnosed by utilizing the characteristics of the phenolic antioxidant.

[0012] Aspect 2 is the diagnostic method according to Aspect 1, wherein the phenolic antioxidant is a compound represented by the following formula (1): According to the diagnostic method of aspect 2, it is possible to utilize the phenomenon in which the gradation value of the B data decreases and then increases.

[0013] Aspect 3 is the diagnostic method according to Aspect 1 or 2, wherein the phenolic antioxidant produces a compound represented by the following formula (2): According to the diagnostic method of aspect 3, it is possible to utilize the phenomenon in which the gradation value of the B data decreases and then increases.

[0014] Aspect 4 is the diagnostic method of Aspect 3, characterized in that it determines whether the gradation value of the B data has increased after the gradation value of the B data has decreased. According to the diagnostic method of Aspect 4, it is possible to diagnose deterioration of a lubricating oil by utilizing the characteristics of a phenolic antioxidant.

[0015] Aspect 5 is the diagnostic method of Aspect 4, characterized in that when the gradation value of the B data decreases and then increases, it is diagnosed that the phenolic antioxidant in the lubricating oil has been consumed. According to the diagnostic method of Aspect 5, it is possible to diagnose deterioration of the lubricating oil by utilizing the characteristics of the phenolic antioxidant.

[0016] A sixth aspect of the present invention is a diagnostic device that includes a storage unit that stores RGB data of a color sensor that detects the color of a lubricant, and a diagnostic unit that diagnoses deterioration of the lubricant, and when the lubricant contains a phenolic antioxidant, the diagnostic unit diagnoses deterioration of the lubricant based on B data of the RGB data. The diagnostic device of the sixth aspect of the present invention can diagnose deterioration of the lubricant by utilizing the characteristics of the phenolic antioxidant.

[0017] ===Present Embodiment==== A preferred embodiment of the present invention will now be described with reference to the drawings.

[0018] <Regarding the diagnostic method> Figure 1 is a graph showing the time change in the detection results of the color sensor and the time change in the residual rate of the antioxidant contained in the lubricating oil. The horizontal axis in each graph represents time. The vertical axis on the left represents the gradation value of each of RGB (red, green, blue). The vertical axis on the right represents the residual rate (%) of the antioxidant. The solid line graph represents the time change in the detection results (RGB data) of the color sensor when the color of the lubricating oil is detected by the color sensor. The dotted line graph represents the time change in the residual rate of the antioxidant. A phenolic antioxidant is added to the lubricating oil.

[0019] The phenolic antioxidant in the lubricating oil measured in Figure 1 is a compound represented by the following formula (1) (2,6-di-tert-butyl-4-methylphenol; hereinafter, DBPC). In the lubricating oil measured in Figure 1, DBPC alone was added to the base oil at 0.5 mass %. DBPC is an example of a phenolic antioxidant.

[0020] The color sensor is a sensor (color detector) for detecting the color of the lubricant. The color sensor has a light-emitting unit and a light-receiving unit. The light-emitting unit irradiates light toward the lubricant, and the light-receiving unit receives the light from the lubricant. The color sensor outputs RGB data (color data including R data, G data, and B data) indicating the gradation values ​​of each of RGB (red, green, blue) according to the amount of light of each color received by the light-receiving unit. The R data is a gradation value indicating the result of receiving light of a red wavelength. The G data is a gradation value indicating the result of receiving light of a green wavelength. The B data is a gradation value indicating the result of receiving light of a blue wavelength. The lower the gradation value of the sensor, the more the lubricant absorbs light of that wavelength.

[0021] As shown by the dotted line in the graph, the residual rate of the antioxidant contained in the lubricant decreases over time. As the residual rate of the antioxidant changes, the detection results of the color sensor also change, as shown by the solid line in the graph.

[0022] As shown by the solid line graph in the figure, as the residual rate of the antioxidant decreases, the B data (data indicating the blue gradation value) decreases, but the R data and G data (data indicating the red and green gradation values) hardly decrease. Thus, when a phenolic antioxidant is contained in a lubricating oil, the B data changes more significantly as the residual rate of the antioxidant decreases than the R data and G data. The reason for this is thought to be that when a phenolic antioxidant is contained in a lubricating oil, the oxidation of the phenolic antioxidant produces yellow quinone compounds that absorb light with blue wavelengths, while intermediate compounds that absorb light with red and green wavelengths are less likely to be produced than quinone compounds.

[0023] When a lubricant deteriorates due to the inclusion of impurities, light of all wavelengths is absorbed, resulting in a decrease in the gradation values ​​of all RGB data colors. In contrast, when the residual rate of the phenolic antioxidant decreases, the B data decreases, but the R and G data show almost no decrease. By utilizing this characteristic, the color of a lubricant containing a phenolic antioxidant is detected with a color sensor, and the change in the B data is compared with the change in the R and G data, making it easier to identify the cause of lubricant deterioration.

[0024] Examples of phenolic antioxidants include 2,6-di-tert-butylphenol, 4,4'-methylenebis(2,6-di-tert-butylphenol), 4,4'-bis(2,6-di-tert-butylphenol), 4,4'-bis(2-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), 4,4'-isopropyl propylidenebis(2,6-di-tert-butylphenol), 2,2'-methylenebis(4-methyl-6-nonylphenol), 2,2'-isobutylidenebis(4,6-dimethylphenol), 2,2'-methylenebis(4-methyl-6-cyclohexylphenol), 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,4-dimethyl-6-tert-butylphenol, 2,6-di-tert-α-dimethylamino-p-cresol, 2,6-di-tert-butyl-4(N , N'-dimethylaminomethylphenol), 4,4'-thiobis(2-methyl-6-tert-butylphenol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), 2,2'-thiobis(4-methyl-6-tert-butylphenol), bis(3-methyl-4-hydroxy-5-tert-butylbenzyl)sulfide, bis(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide, 2,2'-thio-diethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate ], tridecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythrityl-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 3-methyl-5-tert-butyl-4-hydroxyphenyl-substituted fatty acid esters, and the like can be mentioned as preferred examples.These may be used alone or in combination of two or more.

[0025] Among the phenolic antioxidants, those which produce a compound represented by the following formula (2) (3,5,3',5'-tetra-t-butylstilbenequinone; hereinafter, referred to as TBSQ) are particularly preferred.

[0026] When a lubricating oil contains a phenolic antioxidant that forms TBSQ, the phenomenon occurs in which the B data, which had been decreasing, increases after the antioxidant in the lubricating oil is consumed and the residual antioxidant rate reaches nearly 0%, as shown in Figure 1. The occurrence of this phenomenon when a lubricating oil contains a phenolic antioxidant that forms TBSQ will be explained below.

[0027] Major oxidation products of phenolic antioxidants include 2,6-di-tert-butylmethylenequinone (hereinafter referred to as DBMQ), 2,6-di-tert-butyl-4-ethylphenol (hereinafter referred to as DBEP), 3,5-di-tert-butyl-4-hydroxybenzyl methyl ether (hereinafter referred to as HBME), 3,5-di-tert-butyl-4-hydroxybenzaldehyde (hereinafter referred to as BHBA), 3,5-di-tert-butyl-4-hydroxyacetophenone (hereinafter referred to as BHAP), 4,4'-di-hydroxy-3,5,3',5'-tetra-tert-butyldibenzyl (hereinafter referred to as HTBD), and 3,5,3',5'-tetra-t-butylstilbenequinone (TBSQ).

[0028] FIG. 2 is a table showing the main absorption wavelengths of oxidation products, including DBPC. HTBD and TBSQ are candidates for compounds that absorb blue wavelengths (450 nm). FIG. 3 is an explanatory diagram of the DBPC oxidation process. As shown in FIG. 3, HTBD and TBSQ are produced in the DBPC oxidation process. However, based on the following measurement results, the present inventors have identified TBSQ as the compound causing the change in the B data shown in FIG. 1.

[0029] Figures 4A to 4C are chromatograms from a UV-vis detector. Figure 4A is a chromatogram of a lubricant sample taken at timing A in Figure 1. Figure 4B is a chromatogram of a lubricant sample taken at timing B in Figure 1. Figure 4C is a chromatogram of a lubricant sample taken at timing C in Figure 1. The horizontal axis in the figure represents elution time, and the vertical axis in the figure represents wavelength. The bold frame in the figure indicates the blue wavelength region. The left figure in Figure 5 shows the chromatogram of Figure 4B, and the right figure in Figure 5 is a graph of the spectral detection results. As shown in Figures 4B and 5, of the three samples taken at timings A to C, only the sample taken at timing B contains compounds that absorb blue wavelengths.

[0030] Figure 6A is a chromatogram of the sample taken at timing B, and Figure 6B is a chromatogram of the TBSQ standard reagent. Figure 7A is a mass chromatogram of the sample taken at timing B, and Figure 7B is a mass chromatogram of the TBSQ standard reagent. Figure 8A is a mass spectrum of the sample taken at timing B, and Figure 8B is a mass spectrum of the TBSQ standard reagent. As shown in these figures, all measurement results for the sample taken at timing B were consistent with those for the TBSQ standard reagent.

[0031] From the above measurement results, it was determined that the compound causing the change in Data B shown in Figure 1 (the compound that absorbs blue wavelengths in the lubricating oil at timing B) is TBSQ. While TBSQ is shown as the final product in Figure 3, the disappearance of the compound that absorbs blue wavelengths (TBSQ) in Figure 4C suggests that TBSQ disappears due to thermal decomposition or other factors. Therefore, when a lubricating oil contains a phenolic antioxidant that generates TBSQ, TBSQ is generated as the antioxidant residual rate decreases, resulting in a decrease in Data B. After the antioxidant is consumed and the antioxidant residual rate reaches nearly 0%, TBSQ decreases, weakening the absorption of blue wavelengths, and resulting in an increase in Data B. Therefore, when a lubricating oil contains a phenolic antioxidant that generates TBSQ, it is possible to detect the depletion of antioxidants in the lubricating oil by detecting the reversal of the decrease in Data B and an increase.

[0032] 9 is a graph showing the time-dependent change in the detection results of the color sensor and the time-dependent change in the residual rate of the antioxidant contained in another lubricant. The lubricant being measured in FIG. 9 contains a different base oil from that of FIG. 1, to which 0.7 mass% of DBPC has been added, as well as 0.06 mass% of a rust inhibitor and 0.01 mass% of other additives (such as a pour point lowering agent).

[0033] As shown by the solid line in Figure 9, because the lubricating oil contains a phenolic antioxidant, the B data decreases as the antioxidant residual rate decreases, but the R and G data show almost no decrease. Also, as shown in Figure 9, because the lubricating oil contains a phenolic antioxidant that produces TBSQ, the previously decreased B data increases after the antioxidant is consumed and the antioxidant residual rate reaches nearly 0%.

[0034] As described above, when a lubricating oil contains a phenolic antioxidant, the B data decreases as the residual rate of the antioxidant decreases, but the R and G data hardly decrease. Therefore, if RGB data is obtained by detecting the color of a lubricating oil containing a phenolic antioxidant with a color sensor and the deterioration of the lubricating oil is diagnosed based on the B data of the RGB data, the characteristics of the phenolic antioxidant can be utilized to more appropriately diagnose the deterioration of the lubricating oil than when the diagnosis is based on the R and G data.

[0035] Furthermore, when a lubricating oil contains a phenolic antioxidant, if the change in the gradation value of the B data is large relative to the change in the gradation values ​​of the R data and G data of the RGB data, the residual rate of the antioxidant is diagnosed based on the B data. If the change in the gradation values ​​of all colors of the RGB data is large, the contamination of impurities is diagnosed. This allows the characteristics of a lubricating oil containing a phenolic antioxidant to be used to diagnose the cause of lubricating oil deterioration. Note that the diagnosis of lubricating oil deterioration does not necessarily require the determination of the residual rate of the antioxidant itself. For example, the diagnosis of lubricating oil deterioration may require the determination of the period until the residual rate of the antioxidant reaches a predetermined value (the remaining period Pr, described below), the determination of whether the residual rate of the antioxidant has reached a predetermined value, the degree of change in the residual rate of the antioxidant (e.g., whether the deterioration is fast or slow), or the determination of other indicators.

[0036] The phenolic antioxidant is preferably DBPC, which allows the deterioration of the lubricating oil to be diagnosed by utilizing the phenomenon in which the gradation value of the B data decreases and then increases.

[0037] Furthermore, it is desirable that the phenolic antioxidant produces TBSQ. This allows the deterioration of the lubricating oil to be diagnosed by utilizing the phenomenon in which the gradation value of the B data decreases and then increases. However, the phenolic antioxidant that produces TBSQ is not limited to DBPC.

[0038] In diagnosing a lubricant containing a phenolic antioxidant that produces TBSQ, it is desirable to perform a step of determining whether the gradation value of the B data decreases and then increases. In this case, it is desirable to diagnose that the lubricant is out of antioxidant when the gradation value of the B data decreases and then increases. This makes it possible to diagnose deterioration of the lubricant by utilizing the characteristics of the lubricant containing a phenolic antioxidant that produces TBSQ.

[0039] <About the Diagnostic System> Next, a diagnostic system using the above diagnostic method will be described. Fig. 10 is an explanatory diagram of a diagnostic system 100.

[0040] The diagnostic system 100 is a system for diagnosing the deterioration of lubricating oil. The diagnostic system 100 includes a sensor unit 20 having a color sensor 21, and a diagnostic device 40 having a control unit 41 and a storage unit 42. Communication is possible between the sensor unit 20 and the diagnostic device 40 via a communication network 90. ​​The communication network 90 is also connected to a terminal of a lubricating oil user (user terminal 61), a terminal of an authorized dealer or distributor that supplies lubricating oil to lubricating oil users (supplier terminal 71), and the like.

[0041] A user of the lubricant oil has a user terminal 61 and equipment that uses the lubricant oil. The equipment that uses the lubricant oil is, for example, a machine tool or a compressor. The equipment is provided with a tank for storing the lubricant oil (see FIGS. 11A and 11B ). The equipment that uses the lubricant oil (the tank that stores the lubricant oil) is provided with a sensor unit 20 having a color sensor 21. The sensor unit 20 may be attached to an existing tank of the equipment that uses the lubricant oil, or may be provided in advance in the tank of the equipment that uses the lubricant oil.

[0042] FIG. 11A is an explanatory diagram of the sensor unit 20.

[0043] The sensor unit 20 has a color sensor 21, a control unit 23, and a communication unit 24. As already described, the color sensor 21 detects the color of the lubricant and outputs RGB data. The control unit 23 controls the sensor unit 20. The communication unit 24 communicates with the diagnostic device 40 via a communication network 90. ​​For example, the control unit 23 is composed of an arithmetic processing unit such as a CPU or MPU, and a storage device such as a RAM or ROM (main storage device or auxiliary storage device), and the arithmetic processing unit executes a program stored in the storage device, thereby transmitting the detection results of the color sensor 21 (here, RGB data) to the diagnostic device 40 via the communication unit 24.

[0044] 11B is an explanatory diagram of a modified example of the sensor unit 20. The sensor unit 20 may have multiple color sensors 21. Each color sensor 21 detects the color of the lubricant in the tank of a different device. According to the modified sensor unit 20, a single sensor unit 20 can detect the deterioration state of the lubricant in each tank of multiple devices.

[0045] The diagnostic device 40 is a device that diagnoses the deterioration of lubricating oil. As shown in FIG. 10 , the diagnostic device 40 has a control unit 41 and a storage unit 42. The diagnostic device 40 also has an arithmetic processing unit, a storage device, a communication device, etc., which are not shown. The arithmetic processing unit executes programs stored in the storage device, thereby realizing various functions. The diagnostic device 40 may be configured with one computer or multiple computers.

[0046] As will be described later, the control unit 41 diagnoses the timing for changing the lubricant based on the detection results (here, RGB data) of the color sensor 21 stored in the memory unit 42. The control unit 41 also notifies the user terminal 61 and the supplier terminal 71 of the diagnosis results. As shown in FIG. 10 , the control unit 41 has a diagnosis unit 411 and a notification unit 412. The diagnosis unit 411 diagnoses the timing for changing the lubricant based on the RGB data of the color sensor 21. The notification unit 412 notifies the user terminal 61 and the supplier terminal 71 in accordance with the diagnosis results of the diagnosis unit 411. The processing of the control unit 41 (the diagnosis unit 411 and the notification unit 412) will be described later.

[0047] The storage unit 42 includes a profile database and a detection result database.

[0048] The profile database 421 stores profile information indicating the characteristics of the lubricant. FIG. 12 is an explanatory diagram of an example of the profile information. The profile information includes information (graph information) showing the relationship between time and gradation value, a diagnostic color, and a replacement threshold. The profile database 421 stores profile information associated with each type of lubricant. FIG. 12 shows profile information (graph information, diagnostic color, and replacement threshold) for a lubricant containing a phenolic antioxidant that produces TBSQ. The information (graph information) showing the relationship between time and gradation value in FIG. 12 is substantially the same as the data B in FIG. 1. Note that the graph information does not necessarily include data where the antioxidant is near zero% (e.g., data after timing B in FIG. 1). The diagnostic color is information for identifying the data to be used in diagnosing the lubricant from the RGB data detected by the color sensor 21. If the diagnostic color is set to "blue (B)," the "B data" from the RGB data is used in diagnosing the lubricant. In the profile information of a lubricant containing a phenolic antioxidant that produces TBSQ, "blue (B)" is set as the diagnostic color. The change threshold is a threshold used to diagnose whether or not the lubricant needs to be changed. A "gradation value" is set as the change threshold. In the case of the profile information of FIG. 12, a gradation value of "50" is set as the change threshold. Therefore, when diagnosing the lubricant, the gradation value indicated by the "B data" of the RGB data output by the color sensor 21 is compared with the threshold value of "50." When the detection result of the color sensor 21 reaches the change threshold, it indicates that the lubricant has deteriorated to the point where it needs to be changed. In other words, the change threshold is a reference value for determining whether the lubricant needs to be changed (in other words, the change threshold is a reference value for diagnosing the life of the lubricant).

[0049] 13 is an explanatory diagram of an example of the detection result database 422. The detection result database 422 is a database that stores the detection results of the color sensor 21. In the detection result database 422, for each sensor ID, the detection time (detection date and time) is associated with the detection result (RGB data) of the color sensor 21 at that detection time (although each column is left blank in the figure, information on the time and gradation value is stored). The detection result database 422 stores RGB data corresponding to each of a plurality of detection times. In other words, the detection result database 422 stores a history of the detection results (RGB data) of the color sensor 21.

[0050] 14 is a flow diagram of the diagnostic process. The control unit 41 executes each process in the diagram by having the arithmetic processing unit execute a program stored in the storage device of the computer constituting the diagnostic device 40. Here, the diagnostic process for a lubricating oil containing a phenolic antioxidant that produces TBSQ will be described.

[0051] First, the diagnosis unit 411 obtains the history of the detection results (RGB data) of the color sensor 21 from the detection result database 422 (S001). Next, the diagnosis unit determines whether the B data has decreased and then reversed and increased based on the history of the B data (S002). If the B data has decreased and then reversed and increased (YES in S002), the notification unit 412 notifies the user terminal 61 of the user of the lubricant and the supplier terminal 71 of the authorized dealer or agent that supplies the lubricant to the user that the antioxidant in the lubricant has run out (the antioxidant has been consumed) (S006).

[0052] If the result in S002 is NO, the diagnosis unit 411 determines whether the data for all colors (RGB data) are equal to or less than a predetermined value (S003). If the data for all colors (RGB data) are equal to or less than a predetermined value (YES in S003), the notification unit 412 notifies the user terminal 61 of the user of the lubricant and the supplier terminal 71 of the authorized dealer or agent that supplies the lubricant to the user that impurities have been mixed in the lubricant (S007).

[0053] If the result in S003 is NO, the diagnosis unit 411 diagnoses the deterioration of the lubricant based on the B data (data of the color set as the diagnosis color) (S004). Here, as the diagnosis of the deterioration of the lubricant, the timing of changing the lubricant and the remaining period are obtained.

[0054] 15 is an explanatory diagram of the replacement time t1 and remaining life Pr. The horizontal axis in the diagram represents time, and the vertical axis represents gradation value. Time t0 represents the current time. The solid line represents the transition of the detection results of the color sensor 21 (here, B data). The dotted line in the diagram represents the predicted transition of future detection results. Before time t0, the solid line graph represents the past detection results of the color sensor 21 (B data accumulated in the detection result database), and after time t0, the dotted line graph represents the predicted transition of the detection results of the color sensor 21.

[0055] The diagnostic unit 411 expands or contracts the time axis of the graph information in the profile database 421 (see the graph in FIG. 12 ) so that it matches the transition of the detection results of the color sensor 21 up to now (see the solid-line graph in FIG. 15 ). The diagnostic unit 411 then fits the graph with the changed time axis to the transition of the detection results of the color sensor 21 up to now (see the solid-line graph in FIG. 15 ) (by fitting the graph after the change of the time axis to the solid-line graph in FIG. 15 ), thereby obtaining a predicted transition of the detection results (the transition of the future detection results) shown by the dotted line in FIG. 15 . Next, the diagnostic unit 411 calculates the replacement time t1 at which the detection results of the color sensor 21 reach a predetermined threshold Tc. The threshold Tc corresponds to the replacement threshold (see FIG. 12 ) set in the profile information in the profile database 421. Furthermore, the diagnostic unit 411 calculates the remaining life Pr by calculating the difference between the replacement time t1 and the current time t0, as shown in FIG. 15 .

[0056] The rate at which lubricant deterioration progresses is thought to change depending on the usage conditions of the equipment using the lubricant. For example, as the frequency of use of the equipment increases, the lubricant deteriorates more quickly, which is thought to result in a faster change in the detection results of the color sensor 21. Conversely, as the frequency of use of the equipment decreases, the lubricant deterioration is suppressed, which is thought to result in a slower change in the detection results of the color sensor 21. Because the rate at which lubricant deterioration progresses varies in this way, it is thought that predicting future trends in detection results (see the dotted line in Figure 15) based on the most recent progression of lubricant deterioration will result in higher prediction accuracy. Therefore, it is desirable to use newer detection results stored in the detection result database 422 (in other words, without using older detection results) to determine the predicted trend of the detection results shown by the dotted line in Figure 15. This allows for highly accurate prediction of future trends in detection results and for highly accurate diagnosis of the lubricant replacement time t1. However, the predicted trend of the detection results shown by the dotted line in Figure 15 may also be determined using the detection results of the color sensor 21 from the beginning of lubricant use.

[0057] Next, the diagnosis unit 411 determines whether the remaining period Pr calculated in S004 is equal to or greater than a predetermined period (S005). If the remaining period Pr is less than the predetermined period (NO in S005), the notification unit 412 notifies the user terminal 61 of the user of the lubricant and the supplier terminal 71 of the authorized dealer or distributor that supplies the lubricant to the user of the lubricant, recommending a lubricant change (S008). Note that in FIG. 14, if the remaining period Pr is equal to or greater than the predetermined period (YES in S005), the notification unit 412 does not issue a notification, but it may also notify the user terminal 61 or the supplier terminal 71 of information such as the remaining period Pr.

[0058] As described above, the control unit 41 (diagnosis unit 411) obtains RGB data by detecting the color of the lubricating oil containing a phenolic antioxidant using the color sensor 21 (S001), and diagnoses the deterioration of the lubricating oil based on the B data of the RGB data (S004). In the above description, the remaining period Pr is calculated as the diagnosis of lubricating oil deterioration, but the diagnosis of lubricating oil deterioration is not limited to calculating the remaining period Pr. For example, the control unit 41 (diagnosis unit 411) may diagnose the deterioration of the lubricating oil by calculating the replacement time t1 (in other words, the timing when the remaining rate of the antioxidant reaches the replacement threshold), or by determining whether the lubricating oil has reached the replacement time t1, or by determining the degree of change in the remaining rate of the antioxidant (e.g., whether the deterioration is fast or slow).

[0059] Furthermore, the control unit 41 (diagnosis unit 411) determines that impurities have been mixed in when the gradation values ​​of all colors of the RGB data are below a predetermined value (when the gradation values ​​of all colors have changed significantly) (YES in S003). However, the control unit 41 may diagnose only the deterioration of the lubricating oil based on the B data without determining the presence of impurities, and may not perform the processes in S003 and S007. Note that when the lubricating oil contains a phenolic antioxidant, the B data decreases as the antioxidant content decreases, but the R data and G data hardly decrease. This has the advantage of making it easy to identify whether the cause of the lubricating oil deterioration is due to a decrease in the antioxidant content or impurity deterioration.

[0060] Furthermore, although the control unit 41 (diagnosis unit 411) detects in S002 that the gradation value of the B data increases after the gradation value of the B data decreases, the control unit 41 may not perform the process of S002 (and S006). For example, when diagnosing a lubricant in which the gradation value of the B data does not increase after the gradation value of the B data decreases (a lubricant containing a phenolic antioxidant that does not produce TBSQ), the control unit 41 may not perform the process of S002 (and S006). Furthermore, the control unit 41 (diagnosis unit 411) may selectively perform the process of S002 when diagnosing a lubricant in which the gradation value of the B data does not increase after the gradation value of the B data decreases (a lubricant containing a phenolic antioxidant that does not produce TBSQ). Furthermore, the control unit 41 may perform the process of S002 even when diagnosing a lubricant in which the gradation value of the B data does not increase after the gradation value of the B data decreases (a lubricant containing a phenolic antioxidant that does not produce TBSQ). For example, when diagnosing a lubricant containing a phenolic antioxidant in which it is unclear whether TBSQ is produced, the control unit 41 may perform the process of S002.

[0061] The diagnostic device 40 does not need to notify the user terminal 61 or the supplier terminal 71. In other words, the control unit 41 does not need to include the notification unit 412. For example, the control unit 41 (diagnosis unit 411) may simply store the lubricant diagnosis results in the memory unit 42.

[0062] The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. Furthermore, the present invention may be modified or improved without departing from the spirit thereof, and the present invention includes equivalents thereof.

[0063] 20 Sensor unit, 21 Color sensor, 23 Control unit, 24 Communication unit, 40 Diagnostic device, 41 Control unit, 411 Diagnostic unit, 412 Notification unit, 42 Storage unit, 421 Profile database, 422 Detection result database, 61 User terminal, 71 Supplier terminal, 90 Communication network, 100 Diagnostic system

Claims

1. A diagnostic method for diagnosing the deterioration of lubricating oil, The aforementioned lubricating oil contains a phenolic antioxidant, By detecting the color of the lubricating oil with a color sensor, RGB data is obtained from the color sensor. This is a diagnostic method that diagnoses the deterioration of the lubricating oil based on the B data among the RGB data, The phenolic antioxidant produces a compound represented by the following formula (2): 【Chemistry 2】 A diagnostic method characterized by determining whether the grayscale value of the B data increased after the grayscale value of the B data decreased.

2. A diagnostic method according to claim 1, The diagnostic method is characterized in that the phenolic antioxidant is a compound represented by the following formula (1). 【Chemistry 1】

3. A diagnostic method according to claim 1 or 2, A diagnostic method characterized by diagnosing that the phenolic antioxidant in the lubricating oil has been consumed if the grayscale value of the B data increases after a decrease in the grayscale value of the B data.

4. A storage unit that stores RGB data from a color sensor that detects the color of the lubricating oil, A diagnostic unit for diagnosing the deterioration of the lubricating oil and Equipped with, If the lubricating oil contains a phenolic antioxidant, the diagnostic unit is a diagnostic device that diagnoses the deterioration of the lubricating oil based on the B data of the RGB data. The phenolic antioxidant produces a compound represented by the following formula (2): 【Chemistry 2】 A diagnostic device characterized by determining whether the grayscale value of the B data increased after the grayscale value of the B data decreased.

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