WO2024095582A1

WO2024095582A1 - Lubricating oil abnormality detection system, lubricating oil abnormality detection device, lubricating oil abnormality detection method, lubricating oil abnormality detection program and recording medium

Info

Publication number: WO2024095582A1
Application number: PCT/JP2023/031107
Authority: WO
Inventors: 杜継葛西; 竜也楠本
Original assignee: 出光興産株式会社
Priority date: 2022-11-04
Filing date: 2023-08-29
Publication date: 2024-05-10

Abstract

A lubricating oil abnormality detection system (1), which is one embodiment of a lubricating oil abnormality detection system, comprises: an electrical properties acquisition unit (111) for acquiring the electrical properties of a lubricating oil; a minimum value determination unit (114) for determining a minimum value of the lubricating oil; and an abnormal state determination unit (150) for determining an abnormal state of the lubricating oil on the basis of the electrical properties and the determination result regarding the minimum value from the minimum value determination unit.

Description

Lubricant oil abnormality detection system, lubricant oil abnormality detection device, lubricant oil abnormality detection method, lubricant oil abnormality detection program, and recording medium

The present invention relates to a lubricant abnormality detection system, a lubricant abnormality detection device, a lubricant abnormality detection method, a lubricant abnormality detection program, and a recording medium.

Patent Document 1 describes predicting failures in equipment that uses lubricating oil. Patent Document 2 describes diagnosing the degree of deterioration based on color information of the lubricating oil.

Japanese Patent Publication No. 2021-167791 Japanese Patent Publication No. 2020-012690

One aspect of the present invention aims to provide a new technology for determining abnormal conditions in lubricating oil.

In order to solve the above problem, a lubricant abnormality detection system according to one embodiment of the present invention includes an electrical characteristic acquisition unit that acquires electrical characteristic information indicating the electrical characteristics of the lubricant, a minimum value determination unit that determines the minimum value at which the electrical characteristics of the lubricant decrease with use and then begin to increase, and an abnormality determination unit that determines an abnormal state of the lubricant based on the electrical characteristic information acquired by the electrical characteristic acquisition unit and the result of the determination of the minimum value by the minimum value determination unit.

In order to solve the above problems, a lubricant abnormality detection device according to one embodiment of the present invention includes an electrical characteristic acquisition unit that acquires electrical characteristic information indicating the electrical characteristics of the lubricant, a minimum value determination unit that determines the minimum value at which the electrical characteristics of the lubricant decrease with use and then begin to increase, and an abnormality determination unit that determines an abnormal state of the lubricant based on the electrical characteristic information acquired by the electrical characteristic acquisition unit and the result of the determination of the minimum value by the minimum value determination unit.

In order to solve the above problem, a lubricant abnormality detection method according to one aspect of the present invention is a lubricant abnormality detection method executed by one or more computers, and includes an electrical characteristic acquisition step of acquiring electrical characteristic information indicating the electrical characteristics of the lubricant, a minimum value determination step of determining a minimum value that is the minimum value when the electrical characteristics of the lubricant decrease with use and then begin to increase, and an abnormal condition determination step of determining an abnormal condition of the lubricant based on the electrical characteristic information acquired in the electrical characteristic acquisition step and the determination result of the minimum value in the minimum value determination step.

The lubricant abnormality detection device according to one aspect of the present invention may be realized by a computer. In this case, the lubricant abnormality detection program that causes the computer to operate as each part (software element) of the lubricant abnormality detection device to realize the lubricant abnormality detection device on a computer, and the computer-readable recording medium on which the program is recorded, also fall within the scope of the present invention.

According to one aspect of the present invention, a new technology can be provided for determining abnormal conditions in lubricating oil.

1 is a block diagram showing an example of the configuration of a lubricant oil abnormality detection system according to an embodiment of the present invention. FIG. 2 is a flow chart showing the flow of a lubricant abnormality detection method according to an embodiment of the present invention. 1 is a graph showing the capacitance ratio at 30° C. versus ISOT test deterioration time for gas engine oil A containing a calcium detergent and having a calcium content of 0.29 wt %. 4 is a graph showing the capacitance ratio at 30° C. versus ISOT test deterioration time for gas engine oil B containing a calcium detergent and having a calcium content of 0.10 wt %. 1 is a graph showing the capacitance ratio at 30° C. versus the deterioration time in an ISOT test for an engine oil containing no metal-based detergent.

As shown in the reference examples described below, the inventors conducted a detailed analysis of the electrical properties of lubricants over time of use, and discovered that, depending on the type of lubricant containing a metal-based detergent, the electrical properties decrease with use and then have a minimum value when they begin to increase. The electrical properties depend on the type and amount of polar substances, and as the amount of polar substances decreases, the electrical properties decrease, and as the amount of polar substances increases, the electrical properties increase. Since metal-based detergents are polar substances, it is believed that the electrical properties decrease as the metal-based detergent is consumed and its amount decreases. On the other hand, many of the deteriorated substances of the main component oil and additives other than the metal-based detergent are polar substances, and it is believed that the electrical properties increase as the main component oil and additives other than the metal-based detergent deteriorate and the amount of the deteriorated substances increases. The inventors focused on these points and completed the present invention. The lubricant abnormality detection system according to one aspect of the present invention is a new technology that determines the abnormal state of a lubricant by taking into account the minimum value.

[Embodiment]
The configuration of the lubricant oil abnormality detection system 1 according to this embodiment will be described in detail below.

<Configuration of lubricant abnormality detection system 1>
FIG. 1 is a block diagram illustrating an example of the configuration of a lubricant abnormality detection system 1 according to this embodiment.

The lubricant abnormality detection system 1 according to this embodiment includes a lubricant abnormality detection device 10, an electrical property sensor 20, a temperature sensor 30, and a property sensor 40. The lubricant abnormality detection device 10 acquires values measured by each sensor, judges the abnormal state of the lubricant, and displays the judgment result of the abnormal state. Examples of the lubricant abnormality detection device 10 include a computer terminal that can be carried by a user, a stationary computer terminal, and the like. In the case of a portable computer terminal, the user can check the judgment result of the abnormal state displayed on the lubricant abnormality detection device 10 at hand at any time. In addition, the electrical property sensor 20, the temperature sensor 30, and the property sensor 40 may be permanently installed in a container such as a tank in which the lubricant is stored in a machine that uses the lubricant, or may be in contact with the lubricant as necessary. In the case of a permanent installation in a container, the electrical properties, temperature, and properties of the lubricant in the container can be constantly and continuously measured.

(Lubricant Abnormality Detection Device 10)
The lubricant abnormality detection device 10 includes a control unit 100, a storage unit 200, and a display unit 300. The control unit 100, the storage unit 200, the display unit 300, and a communication interface (not shown) described later are connected via a bus. In this embodiment, the control unit 100 and the storage unit 200 are included in the lubricant abnormality detection device 10, but are not limited to this configuration and may be included in an external server separate from the lubricant abnormality detection device 10. In this case, the lubricant abnormality detection device 10 displays the results determined by the external server. The communication interface is an interface that connects to a network. The communication interface may be, for example, a wired connection interface such as Ethernet (registered trademark) or a wireless connection interface such as WiFi (registered trademark), or may be a wired connection interface. For example, the communication interface connects the electrical characteristic acquisition unit 111 and the electrical characteristic sensor 20 so that the electrical characteristic acquisition unit 111 acquires electrical characteristic information from the electrical characteristic sensor 20. The communication interface also connects the temperature acquisition unit 121 and the temperature sensor 30 so that the temperature acquisition unit 121 acquires temperature information from the temperature sensor 30. The communication interface also connects the property acquisition unit 131 and the property sensor 40 so that the property acquisition unit 131 acquires property information from the property sensor 40. Furthermore, the communication interface may connect the abnormal state determination unit 150 and an external server so that the abnormal state determination unit 150 outputs the abnormal state determination result to an external server separate from the lubricant abnormality detection device 10.

(Control unit 100)
The control unit 100 controls each part of the lubricant abnormality detection device 10 by executing a program stored in the storage unit 200. The processor is configured by an integrated circuit such as a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit), for example.

Next, the functional configuration of the control unit 100 will be described. The control unit 100 includes an electrical property unit 110, a temperature unit 120, a property unit 130, a moving average value calculation unit 140, an abnormal state determination unit 150, and a display control unit 160.

(Electrical Characteristic Unit 110)
The electrical characteristic unit 110 is a unit that performs processing related to electrical characteristics and includes an electrical characteristic acquisition section 111, an electrical characteristic temperature correction determination section 112, an electrical characteristic temperature correction section 113, a minimum value determination section 114, and an electrical characteristic comparison section 115.

The electrical characteristic acquisition unit 111 acquires electrical characteristic information indicating the electrical characteristics of the lubricant from the electrical characteristic sensor 20. Examples of electrical characteristics include capacitance, electrical conductivity, and dielectric constant.

The electrical characteristic acquisition unit 111 acquires the electrical characteristic information output from the electrical characteristic sensor 20 via the communication interface. The electrical characteristic acquisition unit 111 outputs the acquired electrical characteristic information to the electrical characteristic temperature correction determination unit 112 and the memory unit 200. The electrical characteristic information is information indicating the results of the measurement of the electrical characteristics of the lubricating oil by the electrical characteristic sensor 20. The electrical characteristic sensor 20 will be described later.

The electrical characteristic temperature correction determination unit 112 determines whether or not temperature correction is required for the electrical characteristic information based on the temperature information acquired by the temperature acquisition unit 121 and the electrical characteristic information acquired by the electrical characteristic acquisition unit 111.

For example, the electrical characteristic temperature correction determination unit 112 compares the temperature information acquired by the temperature acquisition unit 121 with a preset temperature range in which temperature correction of the electrical characteristic information is not required. If the temperature information acquired by the temperature acquisition unit 121 is included in this range, the electrical characteristic temperature correction determination unit 112 determines that temperature correction is not required for the electrical characteristic information. Also, if the temperature information acquired by the temperature acquisition unit 121 is not included in this range, the electrical characteristic temperature correction determination unit 112 determines that temperature correction is required for the electrical characteristic information.

If the electrical characteristic temperature correction determination unit 112 determines that the electrical characteristic information does not require temperature correction, it outputs the electrical characteristic information to the minimum value determination unit 114 and the storage unit 200. If the electrical characteristic temperature correction determination unit 112 determines that the electrical characteristic information requires temperature correction, it outputs the determination result of whether or not the electrical characteristic information requires temperature correction to the electrical characteristic temperature correction unit 113 and the storage unit 200.

If the electrical characteristic temperature correction determination unit 112 determines that temperature correction is required for the electrical characteristic information, the electrical characteristic temperature correction unit 113 performs temperature correction of the electrical characteristic information. For example, the electrical characteristic temperature correction unit 113 accumulates temperature information and electrical characteristic information of the type of lubricant to be determined in advance as a database, and calculates a correction formula (relationship formula) based on the database. The electrical characteristic temperature correction unit 113 performs temperature correction of the electrical characteristic information by referring to the calculated correction formula. Since electrical characteristics are affected by temperature, the abnormality determination unit 150 can more accurately determine an abnormal state of the lubricant by having the electrical characteristic temperature correction unit 113 perform temperature correction.

The electrical characteristic temperature correction unit 113 outputs the electrical characteristic information after temperature correction to the minimum value determination unit 114 and the memory unit 200.

In this embodiment, as described above, the electrical characteristic unit 110 is provided with the electrical characteristic temperature correction determination unit 112 and the electrical characteristic temperature correction unit 113, and the electrical characteristic information is corrected by temperature. However, the present invention is not limited to this form. The electrical characteristic unit 110 may not be provided with the electrical characteristic temperature correction determination unit 112 and the electrical characteristic temperature correction unit 113. In other words, in the present invention, the electrical characteristic information may or may not be corrected by temperature, and the need for temperature correction may or may not be determined. If the electrical characteristic unit 110 does not perform temperature correction of the electrical characteristic information, it is preferable to provide a temperature regulator (not shown) that controls the temperature of the lubricating oil near the electrodes of the electrical characteristic sensor 20. The temperature regulator may be a housing having a space in which the electrodes of the electrical characteristic sensor 20 are stored. At least the detection unit of the temperature sensor 30 and a temperature change device (e.g., a heater) that changes the temperature are stored in the space in the housing in which the electrodes of the electrical characteristic sensor 20 are stored. By pouring lubricant into the space that houses the electrodes of the housing, the detection unit of the temperature sensor 30, and the temperature change device, the temperature of the lubricant that has entered the space is detected based on the value of the temperature sensor 30. Next, it is confirmed whether the temperature of the lubricant that has entered the space is an appropriate value for acquiring electrical characteristic information. If necessary, the temperature of the housing is changed by the temperature change device. The temperature change by the temperature change device may be performed by the control unit 100, or the user of the lubricant abnormality detection system may change the temperature based on the value of the temperature sensor 30 via a controller or the like for controlling the temperature.

The minimum value determination unit 114 determines the minimum value of the lubricant based on the electrical characteristic information acquired by the electrical characteristic acquisition unit 111 or the temperature-corrected electrical characteristic information corrected by the electrical characteristic temperature correction unit 113. The minimum value is the minimum value at which the electrical characteristics decrease as the lubricant is used and then begin to increase. Specifically, the minimum value determination unit 114 (1) determines whether the lubricant being determined is a lubricant having a minimum value, and (2) if it is determined in (1) that the lubricant being determined is a lubricant having a minimum value, it determines the relationship between the current value and the minimum value.

First, in (1), an example of a specific method in which the minimum value determination unit 114 determines whether the lubricant being determined has a minimum value is described below.

As an example, the minimum value determination unit 114 refers to the change over time in the electrical characteristic information stored in the memory unit 200 to determine whether the lubricant being determined has a minimum value. If there is a downward trend from the initial value, the minimum value determination unit 114 determines that the lubricant has a minimum value. Also, if there is an upward trend from the initial value, the minimum value determination unit 114 determines that the lubricant does not have a minimum value.

As another example, the minimum value determination unit 114 refers to a database stored in advance in the storage unit 200 to determine whether the lubricant to be determined is a lubricant having a minimum value. For example, the database contains information on whether each type of lubricant has a minimum value (hereinafter also referred to as minimum value information). The user inputs the type of lubricant to be determined via an input unit (not shown) of the lubricant abnormality detection device 10. The minimum value determination unit 114 determines whether the minimum value information of the input lubricant type is included in the database. If the minimum value determination unit 114 determines that the minimum value information of the input lubricant type is included in the database, it determines whether the lubricant to be determined is a lubricant having a minimum value based on the minimum value information. If the minimum value determination unit 114 determines that the minimum value information of the input lubricant type is not included in the database, it may re-determine the lubricant by, for example, referring to the change over time in the electrical characteristic information described above.

Next, when the minimum value determination unit 114 determines in (1) that the lubricant to be determined has a minimum value, it determines the relationship between the current value and the minimum value in (2). It is preferable that the minimum value determination unit 114 always determines the relationship between the current value and the minimum value. For example, it is preferable to continue determining the minimum value even after once determining that the past value is a minimum value, or even after determining that the current value has already become a minimum value. For example, even if the electrical characteristic has decreased and then started to increase, it may decrease again and then start to increase. In this case, the minimum value determination unit 114 may determine that the minimum values at each time when the characteristic changes from a decrease to an increase are all minimum values. For example, when an abnormal state occurs in which fuel is mixed into a lubricant containing a metal-based cleaning agent, the electrical characteristic may start to increase due to the mixing of fuel, even though the electrical characteristic that has decreased due to the influence of the metal-based cleaning agent has not reached the minimum value that the lubricant inherently has due to its properties. Similarly, the electrical characteristics may also increase due to the inclusion of metal (wear debris) and moisture. In these cases, the minimum value determination unit 114 may first determine that the minimum value when the electrical characteristics change from decreasing to increasing is also a minimum value, and may also determine that the minimum value when the electrical characteristics change from decreasing to increasing due to the presence of a metal-based cleaning agent is also a minimum value. In this way, it is preferable for the minimum value determination unit 114 to continuously determine the minimum values, from the viewpoint of preventing the minimum value caused by the metal-based cleaning agent from being overlooked, even when multiple minimum values occur.

In (2), an example of a specific method in which the minimum value determination unit 114 determines whether a past value is a minimum value is described below. In other words, whether the electrical characteristic has reached a minimum value can be determined by, for example, comparing the current value with the past value. Therefore, the minimum value determination unit 114 determines whether a past value prior to measuring the current value (for example, the measurement value in the immediately preceding measurement) was a minimum value.

As an example, the minimum value determination unit 114 first calculates the difference between the current value and the past value of the electrical characteristic. Here, the "current value" is the measurement value obtained by the current measurement as the target for determining an abnormal state. The "past value" is the measurement value obtained by the measurement immediately before the current measurement. Next, the minimum value determination unit 114 compares the current difference with the previous difference, and determines whether the past value is a minimum value or not depending on whether there is a sign reversal (whether it is positive or negative). Note that the "current difference" is the difference between the current value and the past value, and the "previous difference" is the difference between the measurement value obtained by the measurement immediately before the current measurement and the measurement value obtained by the measurement two measurements before the current measurement. If there is a sign reversal between the current difference and the previous difference, the minimum value determination unit 114 determines that the past value is a minimum value. Furthermore, if there is no sign reversal between the current difference and the previous difference, the minimum value determination unit 114 determines that the past value is not a minimum value. Specifically, a case will be described as an example in which the measured value changes from (1) 100 to (2) 90 to (3) 95. In this case, the difference between (1) and (2) is -10 (negative), and the difference between (2) and (3) is 5 (positive). The minimum value determination unit 114 determines that (2) is the minimum value because there is a reversal of sign between the difference between (1) and (2) and the difference between (2) and (3).

In addition, the minimum value determination unit 114 may compare the current difference with a preset difference threshold value, rather than comparing the current difference with the previous difference. As an example, the minimum value determination unit 114 compares the current value with the past value, and determines whether the calculated current difference is equal to or greater than the preset difference threshold value. If the calculated current difference is equal to or greater than the preset difference threshold value, the minimum value determination unit 114 determines that the past value is a minimum value. If the calculated current difference is less than the preset difference threshold value, the minimum value determination unit 114 determines that the past value is not a minimum value. Specifically, a case will be described in which the preset difference threshold value is 0, and the measured value changes from (1) 100 to (2) 90 to (3) 95. In this case, the difference between (1) and (2) is -10, and the difference between (2) and (3) is 5. The minimum value determination unit 114 determines that (2) is the minimum value because the difference between (2) and (3) is equal to or greater than the preset difference threshold. The specific numerical value of the preset difference threshold described above is merely an example, and the preset difference threshold can be set as appropriate. Note that in this embodiment, the preset difference threshold is set to 0, but the threshold may be set taking error into consideration.

Note that although an example of determining whether a past value is a minimum value or not is described here, the minimum value determination unit 114 may determine that there is a minimum value between the past value and the current value if the current difference is zero. Specifically, a case where the measured value changes from (1) 100 → (2) 90 → (3) 90 → (4) 100 will be described as an example. In this case, the difference between (1) and (2) is -10, the difference between (2) and (3) is 0, and the difference between (3) and (4) is 10. Since the difference between (2) and (3) is 0, the minimum value determination unit 114 determines that there is a minimum value between (2) and (3). In this way, even if the current difference is zero, by making the determination as described above, it is possible to prevent the minimum value from being overlooked.

As yet another example, the minimum value determination unit 114 may make a determination using a trained model obtained by machine learning using the components, electrical property information, temperature information, property information, etc., and the presence or absence, value, etc. of minimum values of electrical properties as training data. The specific configuration of the learning process for obtaining the minimum value determination result is not particularly limited, but machine learning methods such as support vector machines, linear regression, random forests, neural networks, gradient boosting trees, genetic algorithms, gradient descent, and Bayesian optimization can be used.

As yet another example, the current value of the electrical characteristic may be compared with a minimum value threshold value that is set in advance as a minimum value for each type of lubricant to determine the minimum value of the electrical characteristic. If the current value of the electrical characteristic is equal to or less than the threshold value, the minimum value determination unit 114 determines that the current value is a minimum value. If the current value of the electrical characteristic is greater than the threshold value, the minimum value determination unit 114 determines that the current value is not a minimum value.

In addition, when the minimum value determination unit 114 determines that the past value or the current value is not a minimum value, that is, when the lubricant has a minimum value but the past value or the current value is not a minimum value, the minimum value determination unit 114 may further determine the relationship between the past value or the current value and the minimum value. For example, the rate of change from a measurement value before the past value to the past value, or the rate of change from the past value to the current value, may be used to determine when the minimum value will be reached, or an estimated value of the minimum value may be calculated. In addition, for example, if a minimum value (or an estimated value thereof) based on the type of lubricant is stored in the storage unit 200 in advance, the difference from the minimum value may be determined. In addition, the time when the minimum value has already been reached may be determined based on the rate of change from a measurement value before the past value to the past value, or the rate of change from the past value to the current value, etc.

The minimum value determination unit 114 outputs the minimum value determination result to the electrical characteristic comparison unit 115, the moving average value calculation unit 140, the abnormal state determination unit 150, and the memory unit 200.

The electrical characteristic comparison unit 115 compares the current value of the electrical characteristic with a past value. The current value of the electrical characteristic may be a value acquired by the electrical characteristic acquisition unit 111, a value corrected by the electrical characteristic temperature correction unit 113, or a moving average value of the electrical characteristic information calculated by the moving average value calculation unit 140. The electrical characteristic comparison unit 115 may also correct the electrical characteristic information according to the judgment result of the minimum value judgment unit 114 to set it as the current value. The electrical characteristic comparison unit 115 acquires past values of the electrical characteristic from the memory unit 200.

Furthermore, for example, the electrical characteristic comparison unit 115 subtracts a past value from a current value of the electrical characteristic, and determines whether the calculated value is positive or negative. Further, for example, the electrical characteristic comparison unit 115 calculates the difference between the current value and the past value of the above-mentioned electrical characteristic, and compares the calculated difference with a preset difference threshold. Further, for example, the electrical characteristic comparison unit 115 determines whether the calculated difference is equal to or greater than a preset difference threshold.

The electrical characteristic comparison unit 115 outputs the comparison results of the electrical characteristic information to the abnormal state determination unit 150 and the memory unit 200.

In this embodiment, as described below, a form will be described in which deterioration and soot contamination are judged after the determination that the electrical characteristics have reached a minimum value, but the present invention is not limited to this form. For example, depending on the determination result of the minimum value determination unit 114, the electrical characteristics comparison unit 115 may use the determination result to correct the electrical characteristics information and set the corrected value as a past value or a current value. For example, if it is known that the lubricant to be measured is a specific lubricant that contains a metal-based detergent, the electrical characteristics information can be corrected as follows. In this case, for example, the correction may be based on the difference between the behavior of the electrical characteristics when no abnormality occurs in a specific lubricant that contains a metal-based detergent and the behavior of the electrical characteristics when no abnormality occurs in the specific lubricant that does not contain a metal-based detergent.

(Temperature Unit 120)
The temperature unit 120 is a unit that performs processing related to temperature. The temperature unit 120 includes a temperature acquisition unit 121.

The temperature acquisition unit 121 acquires temperature information indicating the temperature of the lubricating oil from the temperature sensor 30. The temperature acquisition unit 121 may acquire the temperature information output from the temperature sensor 30 via a communication interface. The temperature acquisition unit 121 outputs the acquired temperature information to the moving average calculation unit 140, the abnormal state determination unit 150, and the memory unit 200. The temperature information is information indicating the results of the measurement of the temperature of the lubricating oil by the temperature sensor 30. The temperature sensor 30 will be described later.

The current temperature value may be a value acquired by the temperature acquisition unit 121, or may be a moving average value of the temperature information calculated by the moving average value calculation unit 140 described later.

(Property unit 130)
The property unit 130 includes a property acquisition section 131 , a property temperature correction determination section 132 , a property temperature correction section 133 , and a property comparison section 134 .

The property acquisition unit 131 acquires property information indicating the properties of the lubricating oil from the property sensor 40. In this specification, "property" refers to properties other than electrical properties and temperature. For example, properties include viscosity, density, acid value, base value, color tone, etc. In one aspect of the present invention, one or more of these properties may be measured. The property acquisition unit 131 may acquire the property information output from the property sensor 40 via a communication interface. The property acquisition unit 131 outputs the acquired property information to the property temperature correction determination unit 132 and the memory unit 200. The property information is information indicating the results of the property sensor 40 measuring the properties of the lubricating oil. The property sensor 40 will be described later.

The property temperature correction determination unit 132 determines whether or not temperature correction is required for the property information based on the temperature information acquired by the temperature acquisition unit 121 and the property information acquired by the property acquisition unit 131.

For example, the property temperature correction determination unit 132 compares the temperature information acquired by the temperature acquisition unit 121 with a preset temperature range in which temperature correction of the property information is not required. If the temperature information acquired by the temperature acquisition unit 121 is included in this range, the property temperature correction determination unit 132 determines that temperature correction is not required for the property information. Also, if the temperature information acquired by the temperature acquisition unit 121 is not included in this range, the property temperature correction determination unit 132 determines that temperature correction is required for the property information.

If the property temperature correction determination unit 132 determines that the property information does not require temperature correction, it outputs the property information to the property comparison unit 134 and the storage unit 200. If the property temperature correction determination unit 132 determines that the property information requires temperature correction, it outputs the determination result of whether or not the property information requires temperature correction to the property temperature correction unit 133 and the storage unit 200.

When the property temperature correction determination unit 132 determines that temperature correction is necessary for the property information, the property temperature correction unit 133 performs temperature correction of the property information. For example, the property temperature correction unit 133 accumulates temperature information and viscosity information of the type of lubricant to be determined in advance as a database, and calculates a correction formula based on the database. The property temperature correction unit 133 performs temperature correction of the properties by referring to the calculated correction formula. Since the properties are affected by temperature, the property temperature correction unit 133 performs temperature correction, allowing the abnormality determination unit 150 to more accurately determine an abnormal state of the lubricant.

The property temperature correction unit 133 outputs the property information after temperature correction to the property comparison unit 134 and the memory unit 200.

The property comparison unit 134 compares the current property value with the past property value. The current property value may be a value acquired by the property acquisition unit 131, may be a value corrected by the property temperature correction unit 133, or may be a moving average value of the property information calculated by the moving average calculation unit 140 described later. The property comparison unit 134 also acquires past property values from the storage unit 200. As one example, the property comparison unit 134 calculates the difference between the current property value and the past property value, and compares the calculated difference with a preset difference threshold. The property comparison unit 134 determines whether the calculated difference is equal to or greater than the preset difference threshold. As another example, the property comparison unit 134 subtracts the past property value from the current property value, and determines whether the calculated value is positive.

The property comparison unit 134 outputs the comparison results of the property information to the abnormal state determination unit 150 and the memory unit 200.

(Moving average value calculation unit 140)
When the moving average value is used as the current value in the electrical characteristic comparison unit 115, the abnormal state determination unit 150, and the property comparison unit 134, the moving average value calculation unit 140 calculates the moving average value based on multiple values per unit time of the electrical characteristic information, temperature information, and property information.

The moving average value calculation unit 140 outputs the calculated moving average value to the electrical characteristic comparison unit 115, the abnormal state determination unit 150, the property comparison unit 134, and the memory unit 200.

(Abnormal state determination unit 150)
The abnormal state determination unit 150 determines an abnormal state of the lubricant based on the electrical characteristic information acquired by the electrical characteristic acquisition unit 111 and the determination result of the minimum value by the minimum value determination unit 114. Specifically, the abnormal state determination unit 150 determines an abnormal state of the lubricant based on the determination result of the minimum value determined by the minimum value determination unit 114 and the comparison result by the electrical characteristic comparison unit 115. By using the determination result of the minimum value, the abnormal state determination unit 150 can determine an abnormal state when the lubricant to be determined contains a metal-based detergent, thereby eliminating the cause of an extreme polarity change resulting from consumption of the metal-based detergent, and thus can determine an abnormal state with high accuracy.

For example, the abnormal state determination unit 150 can determine an abnormal state of the lubricant by comparing the electrical characteristic information obtained by the electrical characteristic comparison unit 115 with a preset electrical characteristic abnormal value. Also, for example, the abnormal state determination unit 150 can more accurately detect an increase in the electrical characteristics by using the current value of the electrical characteristics corrected according to the result of the determination of the minimum value by the electrical characteristic comparison unit 115, and therefore can more accurately determine an abnormal state.

The abnormal state determination unit 150 may also determine an abnormal state based on the temperature information acquired by the temperature acquisition unit 121 and the property information acquired by the property acquisition unit 131. Specifically, the abnormal state determination unit 150 determines an abnormal state of the lubricant based on the minimum value determination result determined by the minimum value determination unit 114, the comparison result of the electrical property comparison unit 115, the temperature information acquired by the temperature acquisition unit 121, and the comparison result of the property comparison unit 134. By determining an abnormal state by further referring to the temperature information and property information, it is possible to determine an abnormal state with greater accuracy.

When the abnormal state determination unit 150 determines whether an abnormal state is being affected by the electrical characteristics, it is preferable that the abnormal state determination unit 150 determines the abnormal state by referring to the determination result of the minimum value. In this case, for example, the abnormal state determination unit 150 determines the abnormal state after the electrical characteristics reach a minimum value. In other words, in determining an abnormal state that may be affected by the electrical characteristics, the determination result of the minimum value is used as a trigger for the abnormal state determination unit 150 to start determining the abnormal state. By referring to the determination result of the minimum value in this way, it is possible to more accurately determine an abnormal state that may affect the electrical characteristics. Note that, when determining an abnormal state that is not an abnormal state that may be affected by the electrical characteristics, the abnormal state determination unit 150 may continue to determine the abnormal state regardless of the determination result of the minimum value. In other words, in this case, the abnormal state may be determined even before the electrical characteristics reach a minimum value.

The abnormal state is, for example, at least one selected from deterioration, fuel contamination, soot contamination, metal contamination, and water contamination. Deterioration is, for example, deterioration due to at least one of oxidation and heat. In the case of deterioration, the capacitance tends to increase, the viscosity tends to increase, and the density tends to increase. In the case of fuel contamination, the capacitance tends to increase, the viscosity tends to decrease, and the density tends to decrease. In the case of soot contamination, the capacitance tends to decrease, the viscosity tends to increase, and the density tends to increase. In the case of metal (wear powder) contamination, the capacitance tends to increase, the viscosity tends not to change, and the density tends not to change. In the case of water contamination, the capacitance tends to increase significantly, the viscosity tends not to change, and the density tends not to change. The abnormal state determination unit 150 refers to these tendencies to determine various abnormal states.

Examples of abnormal states that may be affected by the electrical characteristics as described above include deterioration and soot contamination. When determining deterioration and soot contamination, the abnormal state determination unit 150 determines deterioration and soot contamination after the point in time when the electrical characteristics reach a minimum value by referring to the electrical characteristic information, temperature information, and property information from that point onward. In other words, when determining an abnormal state of deterioration and soot contamination, the abnormal state determination unit 150 does not determine deterioration and soot contamination until the electrical characteristics reach a minimum value. In other words, in determining deterioration and soot contamination, the determination result of the minimum value is used as a trigger for the abnormal state determination unit 150 to start determining deterioration and soot contamination. Note that when determining metal contamination, moisture contamination, etc., the abnormal state determination unit 150 determines metal contamination, moisture contamination, etc. even before the electrical characteristics reach a minimum value. As mentioned above, even if the minimum value is measured two or more times as a result, the arrival of the first minimum value may be the trigger. If it is determined that there is a second minimum value after the first minimum value, or that there is a high possibility of this occurring, the trigger may not be the arrival of the first minimum value, but rather the arrival of the second or subsequent minimum values.

The abnormal state determination unit 150 outputs the abnormal state determination result to the display control unit 160. The abnormal state determination unit 150 may also output the abnormal state determination result to an external server via a communication interface.

(Display Control Unit 160)
The display control unit 160 controls the display unit 300 to display the abnormal state determination result on the display unit 300. The display control unit 160 outputs the abnormal state determination result determined by the abnormal state determination unit 150 to the display unit 300. When the abnormal state determination unit 150 determines deterioration and soot contamination, the display control unit 160 may cause the display unit 300 to display the current value of the electrical characteristic and a message indicating that the minimum value has not been reached before the electrical characteristic reaches the minimum value, or may not display information regarding the electrical characteristic until the electrical characteristic reaches the minimum value.

(Memory unit 200)
The storage unit 200 stores the program executed by the control unit 100 and various data used by the control unit 100. The storage unit 200 is configured, for example, by a hard disk drive (HDD), a solid state drive (SSD), an electrically erasable programmable read-only memory (EEPROM (registered trademark)), a read only memory (ROM), a random access memory (RAM), or a combination of these. Note that a part or all of the memory is not limited to being built into the lubricant oil abnormality detection device 10, and may be externally attached via an input/output interface (not shown) such as a universal serial bus (USB). In addition, a part or all of the storage unit 200 may be connected to the lubricant oil abnormality detection device 10 via a network as a device independent of the lubricant oil abnormality detection device 10.

The storage unit 200 stores various information. For example, the storage unit 200 stores information such as electrical characteristic information acquired by the electrical characteristic acquisition unit 111, temperature information acquired by the temperature acquisition unit 121, property information acquired by the property acquisition unit 131, electrical characteristic information after temperature correction by the electrical characteristic temperature correction unit 113, property information after temperature correction by the property temperature correction unit 133, the minimum value judgment result judged by the minimum value judgment unit 114, the comparison result by the electrical characteristic comparison unit 115, the comparison result by the property comparison unit 134, the moving average value calculated by the moving average value calculation unit 140, the abnormal state judgment result judged by the abnormal state judgment unit 150, and each preset threshold value.

(Display unit 300)
The display unit 300 is controlled by the display control unit 160. The display unit 300 displays the abnormal state determination result by the abnormal state determination unit 150 that is output from the display control unit 160.

By knowing the results of abnormality detection, users will be able to suggest suitable oils for machines that use lubricants, and predict abnormalities in the machine's parts.

(Electrical property sensor 20)
The electrical property sensor 20 is a sensor for measuring the electrical properties of the lubricant. For example, when measuring the electrostatic capacitance, the electrical property sensor 20 is preferably provided with a comb-shaped electrode. The comb-shaped electrode has a structure in which comb-shaped electrodes are interdigitated. The comb-shaped electrode has such a structure, and thus the distance between the electrodes can be shortened. The distance can be, for example, 20 μm. The material of the electrode is preferably, for example, platinum. By using the comb-shaped electrode of the electrode, the sensitivity of the electrical properties of the oil can be increased. Therefore, the electrical properties can be detected in real time. The electrical property sensor 20 generates electrical property information, which is information indicating the results of measuring the electrical properties of the lubricant, based on the results, and transmits the electrical property information to the lubricant abnormality detection device 10. In this embodiment, the electrical property sensor 20 is described as having a comb-shaped electrode, but the electrical property sensor 20 in the present invention is not limited to such a form, and various conventionally known sensors can be adopted depending on the electrical properties of the object to be measured.

(Temperature sensor 30)
The temperature sensor 30 is a sensor for measuring the temperature of the lubricant. The temperature sensor 30 is not particularly limited as long as it is a sensor that can appropriately measure the temperature of the lubricant in a desired range. The temperature sensor 30 generates temperature information that is information indicating the result of measuring the temperature of the lubricant based on the result, and transmits the temperature information to the lubricant abnormality detection device 10.

(Property sensor 40)
The property sensor 40 is a sensor for measuring the properties of the lubricant. The property sensor 40 is not particularly limited as long as it is a sensor that can appropriately measure the properties of the lubricant in a desired range. The property sensor 40 generates property information that is information indicating the results of measuring the properties of the lubricant based on the results, and transmits the property information to the lubricant abnormality detection device 10.

(Type of lubricant)
The type of lubricant for which the lubricant abnormality detection system 1 according to the present embodiment judges an abnormal state is not particularly limited, and examples thereof include internal combustion engine oil, drive system oil, and equipment oil. Specific examples of lubricants include gas engine oil, gasoline engine oil, and diesel engine oil. The lubricant may or may not contain a metal-based detergent, but the lubricant abnormality detection system 1 according to the present embodiment can be effectively used to judge the abnormal state of a lubricant containing a metal-based detergent. The lubricant abnormality detection system 1 according to the present embodiment judges the abnormal state of the lubricant by taking into account the minimum value of the electrical characteristics, even if the lubricant contains a metal-based detergent, so that it can be judged with high accuracy. Metal-based detergents are used not only in internal combustion engine oils but also in various drive system oils and various equipment oils, so the lubricant abnormality detection system 1 according to the present embodiment can be used to judge the abnormal state of various lubricants.

Examples of metal-based detergents include calcium detergents, magnesium detergents, and sodium detergents.

<Flow of lubricant oil abnormality detection method>
The lubricant abnormality detection system 1 executes a lubricant abnormality detection method. Fig. 2 is a flow chart showing the flow of the lubricant abnormality detection method. As shown in Fig. 2, the lubricant abnormality detection method includes steps S101 to S110.

In step S101, the electrical characteristic acquisition unit 111 acquires electrical characteristic information from the electrical characteristic sensor 20. Also in step S101, the temperature acquisition unit 121 acquires temperature information from the temperature sensor 30. Also in step S101, the property acquisition unit 131 acquires property information indicating the properties of the lubricating oil from the property sensor 40. The electrical characteristic acquisition unit 111 outputs the acquired electrical characteristic information to the electrical characteristic temperature correction determination unit 112 and the storage unit 200, and proceeds to step S102. The temperature acquisition unit 121 outputs the acquired temperature information to the moving average calculation unit 140, the abnormal state determination unit 150, and the storage unit 200, and proceeds to step S109. The property acquisition unit 131 outputs the acquired property information to the property temperature correction determination unit 132 and the storage unit 200, and proceeds to step S106.

In step S102, the electrical characteristic temperature correction determination unit 112 determines whether or not the electrical characteristic information requires temperature correction based on the temperature information acquired by the temperature acquisition unit 121 and the electrical characteristic information acquired by the electrical characteristic acquisition unit 111. If the electrical characteristic temperature correction determination unit 112 determines that the electrical characteristic information requires temperature correction (YES in step S102), the control unit 100 proceeds to processing of S103. If the electrical characteristic temperature correction determination unit 112 determines that the electrical characteristic information does not require temperature correction (NO in step S102), the control unit 100 proceeds to processing of steps S104 and S105.

In step S103, if the electrical characteristic temperature correction determination unit 112 determines that temperature correction is required for the electrical characteristic information, the electrical characteristic temperature correction unit 113 performs temperature correction on the electrical characteristic information. The electrical characteristic temperature correction unit 113 outputs the temperature-corrected electrical characteristic information to the minimum value determination unit 114, the electrical characteristic comparison unit 115, and the storage unit 200, and proceeds to steps S104 and S105.

In step S104, the minimum value determination unit 114 determines the minimum value of the lubricant. The minimum value determination unit 114 outputs the determination result of the determined minimum value to the abnormal state determination unit 150 and the memory unit 200. For example, in step S104, the minimum value determination unit 114 determines whether or not the electrical characteristic has reached a minimum value, and outputs the determination result to the abnormal state determination unit 150 and the memory unit 200.

In step S105, the electrical characteristic comparison unit 115 compares the current value and the past value of the electrical characteristic. Specifically, the electrical characteristic comparison unit 115 uses the electrical characteristic information acquired in step S101, or the electrical characteristic information temperature-corrected in step S103 if temperature correction has been performed, as the current value. The electrical characteristic comparison unit 115 also acquires past values to be compared from the storage unit 200. Then, the electrical characteristic comparison unit 115 compares the current value and the past value. The electrical characteristic comparison unit 115 outputs the comparison result of the electrical characteristic information to the abnormal state determination unit 150 and the storage unit 200, and proceeds to step S110. Note that in step S105, the moving average value calculated by the moving average calculation unit 140 may be used as the current value and the past value of the electrical characteristic. In this case, the moving average value of the electrical characteristic information is calculated by the moving average calculation unit 140 before step S105. Note that, as a modified example of this embodiment, for example, step S105 may be omitted depending on the result of step S104. In other words, the comparison between the current value and the past value of the electrical characteristic performed in step S109 may be performed after it is determined in step S104 that the electrical characteristic has reached a minimum value, but may not be performed if it is determined that the electrical characteristic has not reached a minimum value.

In step S106, the property temperature correction determination unit 132 determines whether or not the property information requires temperature correction based on the temperature information acquired by the temperature acquisition unit 121 and the property information acquired by the property acquisition unit 131. If the property temperature correction determination unit 132 determines that the property information requires temperature correction (YES in step S106), the control unit 100 proceeds to processing of S107. If the property temperature correction determination unit 132 determines that the property information does not require temperature correction (NO in step S106), the control unit 100 proceeds to processing of step S108.

In step S107, if the property temperature correction determination unit 132 determines that the property information requires temperature correction, the property temperature correction unit 133 performs temperature correction on the property information. The property temperature correction unit 133 outputs the temperature-corrected property information to the property comparison unit 134 and the storage unit 200, and proceeds to step S108.

In step S108, the property comparison unit 134 compares the current property value with the past property value. Specifically, the property comparison unit 134 uses the property information acquired in step S101, or, if temperature correction has been performed, the property information temperature-corrected in step S107 as the current property value. The property comparison unit 134 also acquires past values to be compared from the storage unit 200. The property comparison unit 134 then compares the current property value with the past property value. The property comparison unit 134 outputs the comparison result of the property information to the abnormal state determination unit 150 and the storage unit 200, and proceeds to step S109. In step S108, the moving average value calculated by the moving average calculation unit 140 may be used as the current property value and past property value. In this case, the moving average value of the property information is calculated by the moving average calculation unit 140 before step S108.

In step S109, the abnormal state determination unit 150 determines an abnormal state of the lubricant based on the result of the minimum value determination by the minimum value determination unit 114 in step S104, the result of the comparison of the electrical properties by the electrical properties comparison unit 115 in step S105, the temperature information acquired by the temperature acquisition unit 121 in step S101, and the result of the comparison of the properties by the property comparison unit 134 in step S108. The abnormal state determination unit 150 outputs the result of the abnormal state determination to the display control unit 160 and the storage unit 200, and proceeds to step S110. Note that, depending on the result of step S104, some of step S109 is omitted. In other words, among the abnormal state determinations performed in step S109, the determination of an abnormal state that may be affected by the electrical properties described above (e.g., deterioration, soot contamination) is performed after it is determined in step S104 that the electrical properties have reached a minimum value, but is not performed if it is determined that the electrical properties have not reached a minimum value.

In step S110, the display control unit 160 causes the display unit 300 to display the abnormal state determination result determined by the abnormal state determination unit 150. In step S110, the display unit 300 displays the abnormal state determination result by the abnormal state determination unit 150 output from the display control unit 160.

[Software implementation example]
The functions of the lubricant abnormality detection device 10 (hereinafter referred to as the "device") are realized by a program for causing a computer to function as the device, and by a program for causing a computer to function as each control block of the device (particularly each part included in the control unit 100).

In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., a memory) as hardware for executing the program. The functions described in each of the above embodiments are realized by executing the program using this control device and storage device.

The program may be stored in one or more non-transient computer-readable recording media. The recording media may or may not be included in the device. In the latter case, the program may be provided to the system via any wired or wireless transmission medium.

Furthermore, some or all of the functions of each of the control blocks can be realized by a logic circuit. For example, an integrated circuit in which a logic circuit that functions as each of the control blocks is formed is also included in the scope of the present invention. In addition, it is also possible to realize the functions of each of the control blocks by, for example, a quantum computer.

Furthermore, each process described in each of the above embodiments may be executed by AI (Artificial Intelligence). In this case, the AI may run on the control device, or may run on another device (such as an edge computer or a cloud server).

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. The technical scope of the present invention also includes embodiments obtained by appropriately combining the technical means disclosed in the different embodiments.

[Additional Notes]
From the above description, the present invention can be understood, for example, as follows: In order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are conveniently placed in parentheses, but the present invention is not limited to the illustrated embodiments.

The lubricant abnormality detection system (1) according to aspect 1 includes an electrical characteristic acquisition unit (111) that acquires electrical characteristic information indicating the electrical characteristics of the lubricant, a minimum value determination unit (114) that determines a minimum value when the electrical characteristic of the lubricant decreases with use and then begins to increase, and an abnormal state determination unit (150) that determines an abnormal state of the lubricant based on the electrical characteristic information acquired by the electrical characteristic acquisition unit (111) and the result of the determination of the minimum value by the minimum value determination unit.

The lubricant abnormality detection system (1) according to aspect 2 further includes at least one of a temperature acquisition unit (121) that acquires temperature information indicating the temperature of the lubricant and a property acquisition unit (131) that acquires property information indicating the properties of the lubricant in accordance with aspect 1, and the abnormal state determination unit (150) may determine the abnormal state further based on the temperature information acquired by the temperature acquisition unit (121) and the property information acquired by the property acquisition unit (131).

The lubricant abnormality detection system (1) according to aspect 3 may further include a moving average calculation unit (140) that calculates a moving average based on a plurality of values per unit time of at least one selected from the electrical characteristic information, the temperature information, and the property information in aspect 2, and the abnormal state determination unit (150) may determine the abnormal state further based on the moving average value.

The lubricant oil abnormality detection system (1) according to aspect 4 may be the lubricant oil abnormality detection system (1) according to aspect 2 or aspect 3, in which the property is at least one of viscosity and density.

The lubricant abnormality detection system (1) according to aspect 5 may be any one of aspects 1 to 4, in which the abnormal state is at least one selected from deterioration, fuel contamination, soot contamination, metal contamination, and water contamination.

The lubricant abnormality detection system (1) according to aspect 6 may further include, in aspect 2, an electrical characteristic temperature correction determination unit (112) that determines whether or not the electrical characteristic information requires temperature correction based on the temperature information acquired by the temperature acquisition unit (121) and the electrical characteristic information acquired by the electrical characteristic acquisition unit (111), and an electrical characteristic temperature correction unit (113) that performs temperature correction on the electrical characteristic information when the electrical characteristic temperature correction determination unit (112) determines that the electrical characteristic information requires temperature correction.

The lubricant abnormality detection system (1) according to aspect 7 may further include, in aspect 2, a property temperature correction determination unit (132) that determines whether or not temperature correction is required for the property information based on the temperature information acquired by the temperature acquisition unit (121) and the property information acquired by the property acquisition unit (131), and a property temperature correction unit (133) that performs temperature correction of the property information when the property temperature correction determination unit (132) determines that temperature correction is required for the property information.

The lubricant abnormality detection system (1) according to aspect 8 may further include an electrical characteristic sensor (20) that measures the electrical characteristics to obtain the electrical characteristic information in any one of aspects 1 to 7, and the electrical characteristic acquisition unit (111) may acquire the electrical characteristic information from the electrical characteristic sensor (20).

The lubricant abnormality detection system (1) according to aspect 9 may further include a display unit (300) that displays the abnormal state determination result by the abnormal state determination unit (150) in any one of aspects 1 to 8.

The lubricant abnormality detection device (10) according to aspect 10 includes an electrical characteristic acquisition unit (111) that acquires electrical characteristic information indicating the electrical characteristics of the lubricant, a minimum value determination unit (114) that determines a minimum value when the electrical characteristic of the lubricant decreases with use and then begins to increase, and an abnormal state determination unit (150) that determines an abnormal state of the lubricant based on the electrical characteristic information acquired by the electrical characteristic acquisition unit (111) and the result of the determination of the minimum value by the minimum value determination unit (114).

The lubricant abnormality detection method according to aspect 11 is a lubricant abnormality detection method executed by one or more computers, and includes an electrical characteristic acquisition step (S101) for acquiring electrical characteristic information indicating the electrical characteristics of the lubricant, a minimum value determination step (S104) for determining a minimum value that is the minimum value when the electrical characteristic of the lubricant decreases with use and then begins to increase, and an abnormal state determination step (S109) for determining an abnormal state of the lubricant based on the electrical characteristic information acquired in the electrical characteristic acquisition step and the determination result of the minimum value in the minimum value determination step.

The lubricant abnormality detection program according to aspect 12 is a lubricant abnormality detection program for causing a computer to function as the lubricant abnormality detection device (10) according to aspect 10, and is a lubricant abnormality detection program for causing a computer to function as the electrical characteristic acquisition unit (111), the minimum value determination unit (114), and the abnormal state determination unit (150).

The recording medium according to aspect 13 is a computer-readable recording medium on which the lubricant oil abnormality detection program according to aspect 12 is recorded.

[Reference Example]
A reference example of the present invention will be described below.

(Reference Example 1)
Using gas engine oil A containing a calcium detergent (metallic detergent) containing 0.29 wt% calcium, an ISOT (Indiana Stirring Oxidation Test) was performed in accordance with JIS K2514-1:2013 under conditions of 165.5 ° C. and no catalyst. After 0 hours, 72 hours, 96 hours, and 120 hours from the start of the test, a part of the gas engine oil A was collected and cooled to 30 ° C., and the capacitance at 30 ° C. was measured using a comb electrode (manufactured by BAS Co.) with an electrode spacing of 20 μm and made of Pt. The capacitance in air was also measured in the same manner as the blank. The capacitance of the gas engine oil A/the capacitance of the blank was calculated as the capacitance ratio. FIG. 3 shows a graph showing the capacitance ratio at 30 ° C. versus the ISOT test deterioration time of gas engine oil A.

(Reference Example 2)
Gas engine oil B was used, which had the same composition as gas engine oil A, except that the calcium content of the calcium detergent was 0.10 wt %. Otherwise, the ISOT test was carried out in the same manner as in Reference Example 1. The capacitance was measured 0 hours, 24 hours, 48 hours, and 72 hours after the start of the test. Figure 4 is a graph showing the capacitance ratio at 30°C versus the ISOT test deterioration time for gas engine oil B.

(Reference Example 3)
An engine oil containing no metallic detergent was used. The ISOT test was carried out in the same manner as in Reference Example 1. The capacitance was measured 0 hours, 48 hours, 72 hours, and 96 hours after the start of the test. Figure 5 shows a graph showing the capacitance ratio at 30°C versus the ISOT test deterioration time for engine oil containing no metallic detergent.

(result)
In Reference Example 1, it was found that gas engine oil A had a minimum value of the capacitance ratio after 72 hours. In Reference Example 2, it was found that gas engine oil B had a minimum value of the capacitance ratio after 24 hours. Furthermore, in Reference Example 3, it was found that the engine oil without a metal-based detergent had no minimum point. From the results of Reference Examples 1 to 3, it was revealed that the lubricating oil had a minimum value of the capacitance ratio when it contained a metal-based detergent, and did not have a minimum value of the capacitance ratio when it did not contain a metal-based detergent.

Electrical properties depend on the type and amount of polar substances, and as the amount of polar substances decreases, the capacitance decreases, and as the amount of polar substances increases, the electrical properties increase. Metallic detergents are polar substances, so it is thought that the capacitance decreases when the metallic detergent is consumed and the amount decreases. Therefore, in the case of gas engine oil A and gas engine oil B, which contain metallic detergents, it is thought that the capacitance ratio decreased due to the consumption (deterioration) of the metallic detergent. Furthermore, many of the deteriorated substances of the main component oil and additives other than the metallic detergent are polar substances, and it is thought that the electrical properties increase due to the deterioration of the main component oil and additives other than the metallic detergent and the increase in the amount of the deteriorated substances. Therefore, the increase after exceeding the minimum point of gas engine oil A and gas engine oil B containing metallic detergents is thought to be due to the deterioration of the main component oil and additives other than the metallic detergent. Furthermore, the increase in the capacitance of engine oil without metallic detergent from the initial value is thought to be due to the deterioration of the main component oil and additives.

REFERENCE SIGNS LIST 1 Lubricant abnormality detection system 10 Lubricant abnormality detection device 20 Electrical property sensor 30 Temperature sensor 40 Property sensor 100 Control unit 110 Electrical property unit 111 Electrical property acquisition section 112 Electrical property temperature correction judgment section 113 Electrical property temperature correction section 114 Minimum value judgment section 115 Electrical property comparison section 120 Temperature unit 121 Temperature acquisition section 130 Property unit 131 Property acquisition section 132 Property temperature correction judgment section 133 Property temperature correction section 134 Property comparison section 140 Moving average value calculation section 150 Abnormal state judgment section 160 Display control section 200 Memory section 300 Display section

Claims

an electrical characteristic acquisition unit that acquires electrical characteristic information indicating electrical characteristics of the lubricant;
a minimum value determination unit that determines a minimum value when the electrical characteristic of the lubricating oil decreases with use and then starts to increase;
a lubricant abnormality detection system comprising: an abnormality determination unit that determines an abnormal state of the lubricant based on the electrical characteristic information acquired by the electrical characteristic acquisition unit and the result of the minimum value determination by the minimum value determination unit.
The lubricant is further provided with at least one of a temperature acquisition unit that acquires temperature information indicating a temperature of the lubricant and a property acquisition unit that acquires property information indicating a property of the lubricant,
The lubricant abnormality detection system according to claim 1 , wherein the abnormal state determination unit determines the abnormal state further based on the temperature information acquired by the temperature acquisition unit and the property information acquired by the property acquisition unit.
a moving average value calculation unit that calculates a moving average value based on a plurality of values per unit time of at least one selected from the electrical characteristic information, the temperature information, and the property information,
The lubricant abnormality detection system according to claim 2 , wherein the abnormality determination unit determines the abnormality further based on the moving average value.
The lubricant abnormality detection system according to claim 2, wherein the property is at least one of viscosity and density.
The lubricant abnormality detection system according to claim 1, wherein the abnormal state is at least one selected from deterioration, fuel contamination, soot contamination, metal contamination, and water contamination.
an electrical characteristic temperature correction determination unit that determines whether or not temperature correction is required for the electrical characteristic information based on the temperature information acquired by the temperature acquisition unit and the electrical characteristic information acquired by the electrical characteristic acquisition unit;
The lubricant abnormality detection system according to claim 2 , further comprising an electrical characteristic temperature correction unit that performs temperature correction of the electrical characteristic information when the electrical characteristic temperature correction determination unit determines that temperature correction is required for the electrical characteristic information.
a property temperature correction determination unit that determines whether or not temperature correction is required for the property information based on the temperature information acquired by the temperature acquisition unit and the property information acquired by the property acquisition unit;
The lubricant abnormality detection system according to claim 2 , further comprising a property temperature correction unit that performs temperature correction of the property information when the property temperature correction determination unit determines that temperature correction is required for the property information.
an electrical characteristic sensor for measuring the electrical characteristic to obtain the electrical characteristic information;
The lubricant abnormality detection system according to claim 1 , wherein the electrical characteristic acquisition unit acquires the electrical characteristic information from the electrical characteristic sensor.
The lubricant abnormality detection system according to any one of claims 1 to 8, further comprising a display unit that displays the abnormality determination result by the abnormality determination unit.
an electrical characteristic acquisition unit that acquires electrical characteristic information indicating electrical characteristics of the lubricant;
a minimum value determination unit that determines a minimum value when the electrical characteristic of the lubricating oil decreases with use and then starts to increase;
a lubricant abnormality detection device comprising: an abnormality determination unit that determines an abnormal state of the lubricant based on the electrical characteristic information acquired by the electrical characteristic acquisition unit and the result of the minimum value determination by the minimum value determination unit.
A lubricant abnormality detection method executed by one or more computers, comprising:
An electrical characteristic acquisition step of acquiring electrical characteristic information indicating electrical characteristics of the lubricant;
a minimum value determination step of determining a minimum value at which the electrical property of the lubricating oil decreases with use and then starts to increase;
A lubricant abnormality detection method comprising: an abnormality determination step of determining an abnormal state of the lubricant based on the electrical characteristic information acquired in the electrical characteristic acquisition step and the result of the minimum value determination step.
A lubricant abnormality detection program for causing a computer to function as the lubricant abnormality detection device described in claim 10, the lubricant abnormality detection program causing a computer to function as the electrical characteristic acquisition unit, the minimum value determination unit, and the abnormal state determination unit.
A computer-readable recording medium having recorded thereon the lubricant abnormality detection program according to claim 12.