JPH09100712A - Method for predicting lubricating oil life and lubricating oil life predicting device using this method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for predicting a lubricating oil life, which is capable of accurately predicting the remaining life of lubricating oil even when a change occurs in a vehicular traveling pattern and directly displaying a distance to be traveled until the life of the lubricating oil expires. SOLUTION: A lubricating oil life predicting device is provided with a lubricating oil analyzing means 2 for analyzing the rate of a pentane insoluble amount contained in lubricating oil or the total acid value of the lubricating oil by measuring the infrared ray absorption level of the lubricating oil, a traveling distance measuring means 8 for integrating traveling distances from the time of exchanging the lubricating oil with another, a calculating means 4 for selecting a function having a highest relative coefficient from a plurality of preset functions as a regression approximate curve by using the measured deterioration level of the lubricating oil and the traveling distance and calculating a distance to be traveled by applying the limit value of the deterioration of the lubricating oil to the regression approximate curve and a display means 9 for displaying the calculated distance to be traveled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating oil life predicting method and apparatus, and more particularly to a lubricating oil life predicting method and apparatus suitable for predicting the life of engine oil for automobiles.

[0002]

2. Description of the Related Art Conventional systems for detecting deterioration of engine oil are of a type that determines the oil replacement timing based on the distance traveled, and a type that determines changes in oil properties by various types of sensors. Is roughly divided into

In the former, there is a method of simply displaying the traveling distance after the last oil change, and a method of correcting the replacement time by the difference in engine speed and oil temperature at that time even when traveling the same distance.

The values shown in Table 1 below are generally known as a measure of oil deterioration that the latter intends to judge (for example, "Introduction to Reliability Technology for Automotive Engines", Internal Combustion Engine Vol. 100 1987).

[0005]

[Table 1] If the running conditions are constant, the pentane-insoluble content in the above evaluation items is such that the contaminants and wear debris mixed in the lubricating oil increase in almost direct proportion to the operating time, and the total acid value is It is known that it increases due to thermal deterioration of the lubricating oil, and that it changes like a quadratic curve with respect to the operating time.

The changes in pentane insoluble matter and total acid value with respect to this use time are shown in FIGS. 6 and 7, respectively, and a method for estimating the remaining life of lubricating oil using this relationship is disclosed in Japanese Patent Laid-Open No. 3-31746. It is disclosed in the publication.

[0007]

However, in the above-described conventional method for estimating the remaining life of the lubricating oil, the remaining life of the lubricating oil is displayed by operating time. However, there is a problem in that the travelable distance indicating whether or not the vehicle can travel is not directly displayed.

Further, since the remaining life is estimated on the assumption that the traveling condition is constant, there is a problem that the estimation accuracy is poor when the traveling pattern of the vehicle changes and the error is very large.

In view of the above problems, a first object of the present invention is to provide a lubricating oil life predicting method for directly displaying a travelable distance until the life of the lubricating oil is exhausted.

A second object of the present invention is to provide a lubricating oil life predicting method capable of accurately predicting the remaining life of the lubricating oil even if the running pattern of the vehicle changes.

[0011]

To solve the above-mentioned problems, the present invention has the following arrangement. That is, the invention according to claim 1 includes a lubricating oil analysis process for obtaining a deterioration degree of the lubricating oil,
The gist of the present invention is to include a mileage measurement process for obtaining a mileage after the replacement of the lubricating oil and a calculation process for calculating a mileage using the obtained deterioration degree of the lubricating oil and the mileage. This is a method for predicting the lubricating oil life.

According to a second aspect of the present invention, in the lubricating oil life predicting method according to the first aspect, the calculation process is a regression analysis of the deterioration degree of the lubricating oil with respect to the traveled distance, and a plurality of predetermined functions are used. The gist is to select the function having the highest correlation coefficient as the regression approximation curve and apply the limit value of the deterioration degree of the lubricating oil to the regression approximation curve to calculate the travelable distance.

Even if the running pattern of the vehicle changes in this way, by selecting a regression approximation curve that best fits the measured value of the degree of deterioration of the lubricating oil with respect to the actual running distance,
The remaining life of the lubricating oil can be accurately predicted.

According to a third aspect of the present invention, in the lubricating oil life prediction method according to the first or second aspect, the deterioration degree of the lubricating oil is the proportion of the pentane insoluble matter contained in the lubricating oil or the lubricating oil. The gist is that it is the total acid value of.

According to a fourth aspect of the present invention, a lubricating oil analyzing means for measuring the deterioration degree of the lubricating oil, a traveling distance measuring means for accumulating the traveling distance after the lubricating oil is replaced, and the measured lubricating oil A lubricating oil life prediction device comprising: a calculating unit that calculates a travelable distance using a deterioration degree and a traveling distance; and a display unit that displays the calculated travelable distance.

According to a fifth aspect of the present invention, in the lubricating oil life predicting apparatus according to the fourth aspect, the calculating means performs a regression analysis of the deterioration degree of the lubricating oil with respect to the traveling distance, and uses a plurality of predetermined functions. The gist is to select the function having the highest correlation coefficient as the regression approximation curve and apply the limit value of the deterioration degree of the lubricating oil to the regression approximation curve to calculate the travelable distance.

According to a sixth aspect of the present invention, in the lubricating oil life predicting apparatus according to the fourth or fifth aspect, the lubricating oil analysis means measures infrared absorption of the lubricating oil and pentane contained in the lubricating oil. The gist is to analyze the ratio of insoluble matter or the total acid number of the lubricating oil.

[0018]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a system configuration diagram showing a configuration of a lubricating oil life prediction device according to the present invention. FIG.
In the lubricant oil life prediction device 1, the lubricant oil analysis device 2
, An analog / digital converter (hereinafter abbreviated as A / D converter) 3, a microcomputer 4, a random access memory (hereinafter abbreviated as RAM) 5
, Read only memory (hereinafter abbreviated as ROM) 6, reset button 7, and travel distance input device 8
And a display device 9.

FIG. 2 is a sectional view along the optical axis showing the detailed structure of the lubricating oil analyzer 2. The lubricating oil analyzer 2 is
It comprises a ceramic heater 21, a lubricating oil passage 23 having a transparent window 22, a condenser lens 24, a shutter 25, a bandpass filter 26, and a light receiving element 27.

Ceramic heater 21, transparent window 22, condenser lens 24, shutter 25, bandpass filter 26
The light receiving element 27 and the light receiving element 27 are coaxially arranged in this order. Infrared rays radiated from the ceramic heater 21 which generates heat when energized enter the lubricating oil passing through the inside of the lubricating oil passage 23 through the transparent window 22, are absorbed and attenuated according to the deterioration degree of the lubricating oil, The light is condensed by the condensing lens 24, becomes an intermittent light of the opening / closing cycle of the shutter 25, the wavelength of the measurement target is selected by the bandpass filter 26, and enters the light receiving element 27.

Condensing lens 24 and bandpass filter 2
The shutter 25 provided between the shutter 6 and 6 functions as a chopper that opens and closes at a constant cycle. This is because the pyroelectric characteristic of the light receiving element 27 does not respond to direct current, so that the light receiving element 27 can measure the amplitude of the alternating current component of the transmitted light by the transmitted light that is intermittent in the chopper cycle.

The center wavelength selected by the bandpass filter 26 in the present embodiment is 5.5 μm when analyzing pentane insoluble matter as the degree of deterioration of the lubricating oil, and as the degree of deterioration of the lubricating oil. When analyzing the total acid value, it is 8.5 μm. The bandpass filter 26 is
The two kinds of wavelengths may be selectively switched so that the pentane-insoluble matter and the total acid value can be analyzed together.

The light receiving element 27 is a light receiving element utilizing the pyroelectric effect of a ferroelectric substance, detects a temperature change of the light receiving element due to infrared rays as a surface charge of a ferroelectric crystal, and has a built-in voltage change due to this charge. It is transmitted to the gate of the FET and output as the drain current of this FET.

In this way, the lubricating oil analyzer 2 can obtain the output current of the light receiving element 27 according to the degree of deterioration of the lubricating oil.
The signal is converted into a digital signal by the / D converter 3 and taken into the microcomputer 4.

The microcomputer 4 has a travel distance,
Non-volatile RA that stores the analysis value of the lubricating oil, the number of analysis times, etc.
M5, a program executed by the microcomputer 4, a ROM 6 that stores various regression approximation curves and the limit value of the deterioration degree of the lubricating oil, a reset button 7 that notifies the microcomputer 4 that the lubricating oil has been replaced, and a travel distance pulse Is connected to a microcomputer 4 and a display device 9 for displaying a travelable distance and a lubricating oil replacement instruction.

Table 2 below shows an example of the total regression approximated curve stored in the ROM 6 in advance.

[0027]

[Table 2] FIG. 3 is an explanatory diagram in the case where the life of the lubricating oil is predicted based on the analysis of the pentane insoluble matter in the present embodiment, and the travelable distance that can be traveled before the life of the lubricating oil is exhausted is obtained. If the limit value of the pentane insoluble content of the lubricating oil used is 3 wt%, the pentane insoluble content is 3 wt%.
The output signal value of the lubricating oil analyzer 2 corresponding to is stored in the ROM 6 as the limit value of the deterioration degree of the lubricating oil. Further, the linear approximation described in item No. 1 of Table 2 is specified as the initial curve.

Then, when the lubricating oil is replaced with new lubricating oil and the reset button is pressed (travel distance = 0 km) and every predetermined traveling distance (for example, 1,000 km), the lubricating oil analyzer 2 determines that the lubricating oil is not pentane. The dissolved component is analyzed, and the microcomputer 4 takes in a signal corresponding to the concentration.
Then, the regression analysis is performed on all of the regression approximation curves (functions) shown in Table 2 for the initial analysis value and the analysis value for each predetermined traveling distance, and the coefficient with the highest approximation accuracy is obtained for each curve. Next, the correlation coefficient is calculated for each curve, the curve having the maximum correlation coefficient is selected as the regression approximation curve, and the travelable distance is calculated and displayed from this curve and the limit value.

FIG. 4 is an explanatory diagram for predicting the life of the lubricating oil based on the analysis of the total acid value in the present embodiment, and obtaining the travelable distance that can be traveled before the life of the lubricating oil is exhausted. . Assuming that the limit value of the increase in total acid value of the lubricating oil used is 2.5 [mgKOH / g], the output signal value of the lubricating oil analyzer 2 corresponding to this value and the total acid value is R
Store in OM6. As the initial curve, the polynomial approximation described in item No. 3 of Table 2 is specified. Then, 2.5 was added to the total acid value C at reset (C + 2.5) [m
The output signal value of the lubricating oil analyzer 2 corresponding to gKOH / g] is stored in the RAM 5 as the limit value of the lubricating oil deterioration degree.
The subsequent operation is almost the same as the case of analyzing pentane insoluble matter.

FIG. 5 is a flow chart showing the operation of the microcomputer 4 when predicting the life of the lubricating oil based on the analysis of the pentane insoluble matter. First, the user of the vehicle presses the reset button 7 when replacing the new lubricating oil, and instructs the microcomputer 4 to predict the life of the new lubricating oil.

When the microcomputer 4 detects that the reset button 7 has been pressed (when the determination in step S10 is Yes), the traveling distance storage area, the lubricating oil analysis value storage area, and the number of analysis times (N) storage of the RAM 5 are stored. Each area is cleared (step S12). Next, the first lubricating oil analysis is performed, the analysis value is stored in the first analysis value storage area of the RAM 5, and the analysis count is updated by adding 1 to the analysis count, and the analysis count is stored in the analysis count storage area of the RAM 5. It is stored (step S14).

Next, the analysis value this time is compared with the limit value of the deterioration degree of the lubricating oil stored in the ROM 6 (step S
16) If the analysis value is greater than or equal to the limit value (step S16)
If the judgment is No), an error is displayed and the operation is stopped.
When the analysis value is less than the limit value (when the determination in step S16 is Yes), the analysis value reaches the limit value using the curve designated as the initial curve among the plurality of regression approximate curves stored in the ROM 6 in advance. Is calculated and displayed (step S18), and the process returns to step S10.

If the determination in step S10 is Yes,
It is determined whether or not a travel distance pulse has been input from the travel distance input device 8 (step S20). If no travel distance pulse has been input (if the determination in step S20 is No), nothing is performed and the process returns to step S10.

If a mileage pulse is input (if the determination in step S20 is Yes), the mileage value stored in the mileage storage area of the RAM 5 is read and the distance represented by one mileage pulse is added. Then, the mileage is updated and stored again in the RAM 5 (step S22). Next, it is determined whether or not the updated traveling distance is a predetermined execution unit for predicting the lubricating oil life (step S24).

This prediction execution unit is an interval at which the display of the travelable distance showing the remaining life of the lubricating oil is updated by evaluating the traveling distance up to now and the corresponding analysis value of the deterioration degree of the lubricating oil by regression analysis. In this embodiment, for example, the travel distance is set to every 1,000 km. If the predicted execution unit is too small, the travelable distance fluctuates due to an error in the analysis value, which is not preferable. If the predicted execution unit is too large, the lubricating oil replacement time will be missed.

If the determination in step S24 is No, nothing is done and the process returns to step S10. If the result of the determination in step S24 is Yes, a lubricating oil analysis is performed, and the analysis value is R
The number of analyzes is stored in the Nth analysis value storage area of AM5, and the number of analyzes is updated by adding 1 to the number of analysis times N, and the number of analysis times is stored in the number of analysis times storage area of the RAM 5 (step S2).
6).

Next, the analysis value this time is compared with the limit value of the deterioration degree of the lubricating oil stored in the ROM 6 (step S
28), if the analysis value is greater than or equal to the limit value (step S28)
If the determination is No, the travelable distance is 0 and a lubricating oil replacement instruction is displayed (step S30), and the operation ends.

If the analysis value is less than the limit value (step S
If the determination at 28 is Yes), it is determined whether the number of analysis times N exceeds 2 (step S32). If the number of analyzes N is 2 or less (No in the determination in step S32, actually only N = 2), the process proceeds to step S18.

If the number of analyzes N is 3 or more (step S
32) Yes), referring to the analysis value obtained by analyzing the lubricating oil for each predetermined travel distance stored in the analysis value storage area of the RAM 5, the relational expression between the travel distance and the analysis value is RO
Regression is performed using the total regression approximation curve stored in M6 (step S34). Next, the correlation coefficient (R ² ) between each regression approximation curve and the actual measurement analysis value is calculated (step S36), and the regression approximation curve having the largest correlation coefficient is selected (step S36).
38), using the selected regression approximation curve, the travelable distance that can be traveled before the limit value of the deterioration degree of the lubricating oil is reached is calculated and displayed (step S4).
0), and returns to step S10.

When predicting the life of a lubricating oil based on the analysis of the total acid number, the limit value of the analysis value is not a constant,
Since the initial value (C) of the total acid value is, for example, 2.5, a value obtained by adding 2.5 to the first analysis value after reset is stored in the RAM 5 as a limit value, and thereafter stored in the RAM 5. The difference from the flowchart of FIG. 5 is that the limit values that are set are referred to.

Next, a modification of the embodiment will be described. In the above-described embodiment, the lubricating oil analysis means measures the infrared absorption of the lubricating oil to analyze either the proportion of the pentane-insoluble matter contained in the lubricating oil or the total acid value of the lubricating oil. When the central wavelength selected by the bandpass filter 26 is switchable and the pentane insoluble matter and the total acid value are both analyzed, the smaller one of the travelable distances predicted from the respective analysis values is displayed. Is preferred.

In addition to the display of the travelable distance, the reliability of the travelable distance, for example, a value obtained by multiplying the correlation coefficient of the regression approximation curve by 100 may be simultaneously displayed.

Further, instead of analyzing the lubricating oil for each constant traveling distance, the lubricating oil may be analyzed for each constant operating time to calculate the travelable distance.

Since the method of regression analysis and the method of obtaining the correlation coefficient itself are well known, the explanation thereof is omitted, but Takeshi Hayakawa "Basics of regression analysis" (Asakura Shoten) and Minoru Tajima et al. The theory of least squares method and its application "(Toyo Shoten).

[0045]

As described above, according to the lubricating oil life prediction method of the present invention, the lubricating oil analysis process for obtaining the deterioration degree of the lubricating oil and the traveling distance measurement process for obtaining the traveling distance after the replacement of the lubricating oil are performed. And the calculation process of calculating the travelable distance using the obtained deterioration degree of the lubricant oil and the traveled distance, the effect that the remaining life of the lubricant oil can be indicated by the travelable distance is provided. is there.

Further, according to the present invention, in the calculation process for calculating the travelable distance, the degree of deterioration of the lubricating oil with respect to the traveled distance is subjected to regression analysis, and the correlation coefficient is highest from a plurality of predetermined functions. Select the function as the regression trendline,
By fitting the limit value of the degree of deterioration of the lubricating oil to the regression approximation curve and calculating the travelable distance, the measured value of the degree of deterioration of the lubricating oil with respect to the actual traveling distance can be calculated even if the traveling pattern of the vehicle changes. By selecting the best-fitting regression approximation curve, it is possible to accurately predict the remaining life of the lubricating oil. As a result, it is possible to prevent wasteful replacement of the lubricating oil and prevent the life of the engine or the like from being shortened due to the deteriorated lubricating oil, which contributes to energy saving, reduction in vehicle operation cost, environmental protection, and the like.

Further, according to the lubricating oil life predicting apparatus of the present invention, the lubricating oil analyzing means measures the infrared absorption of the lubricating oil to determine the proportion of pentane-insoluble matter contained in the lubricating oil or the total acid value of the lubricating oil. By the analysis, there is an effect that it is possible to provide a small and lightweight lubricating oil life prediction device that can be mounted on a vehicle.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing a configuration of a lubricating oil life prediction device according to the present invention.

FIG. 2 is a plan view showing the configuration of a lubricating oil analyzer.

FIG. 3 is a graph illustrating a method of predicting a travelable distance from a pentane insoluble matter value and a traveled distance.

FIG. 4 is a graph illustrating a method of predicting a travelable distance from a total acid value and a traveled distance.

FIG. 5 is a flowchart illustrating an operation of the lubricating oil life prediction device.

FIG. 6 is a graph illustrating a conventional method for predicting the remaining life of lubricating oil from the pentane insoluble matter value and running time.

FIG. 7 is a graph illustrating a conventional method for predicting the remaining life of a lubricating oil from the total acid value and running time.

[Explanation of symbols]

1 Lubricating oil life prediction device 2 Lubricating oil analyzer 3
A / D converter 4 Microcomputer 5 R
AM 6 ROM 7 Reset button 8 Mileage input device 9 Display device

Claims (6)

[Claims] 1. A method for analyzing a lubricating oil for determining a degree of deterioration of lubricating oil, a step for measuring a traveling distance for determining a traveling distance after replacement of the lubricating oil, and a step for measuring a degree of deterioration of the lubricating oil and a traveling distance obtained based on the traveling degree. A lubricating oil life prediction method comprising: a calculation process for calculating a travelable distance; 2. The calculation process comprises performing a regression analysis of the degree of deterioration of the lubricating oil with respect to the traveling distance, selecting a function having the highest correlation coefficient from a plurality of predetermined functions as a regression approximation curve, and the regression approximation curve. The travelable distance is calculated by fitting the limit value of the deterioration degree of the lubricating oil to
Lubricating oil life prediction method described. 3. The lubricating oil life according to claim 1 or 2, wherein the deterioration degree of the lubricating oil is a ratio of a pentane insoluble component contained in the lubricating oil or a total acid value of the lubricating oil. Prediction method. 4. Lubricating oil analysis means for measuring the degree of deterioration of lubricating oil, traveling distance measuring means for accumulating the traveling distance after replacement of lubricating oil, and the measured degree of deterioration and traveling distance of lubricating oil. A lubricating oil life prediction device comprising: a calculating unit that calculates a travelable distance using the display unit; and a display unit that displays the calculated travelable distance. 5. The regression calculating means calculates regression of the degree of deterioration of the lubricating oil with respect to the traveling distance, selects a function having the highest correlation coefficient from a plurality of predetermined functions as a regression approximation curve, and the regression approximation curve 5. The travelable distance is calculated by fitting the limit value of the degree of deterioration of the lubricating oil to.
Lubricating oil life prediction device described. 6. The lubricating oil analyzing means measures infrared absorption of the lubricating oil to analyze a ratio of a pentane-insoluble component contained in the lubricating oil or a total acid value of the lubricating oil. Alternatively, the lubricating oil life prediction device according to claim 5.