RU2495415C2 - Method for effective monitoring of lubricating oil operability, and device for its implementation - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: optic emission beam exciting oil fluorescence is directed at the controlled oil; fluorescence intensity of fresh oil is measured simultaneously at three spectrum ranges and two operating spectrum ranges are determined, in which values of intensities are higher than in the third one; fluorescence intensity is measured during oil operation; oil ageing index is determined as ratio of intensities in working spectrum ranges, and oil operability is evaluated as per the ageing index. Optic emission exciting oil fluorescence is polarised, and in addition, fluorescence intensities are measured simultaneously with parallel and perpendicular emission polarisation relative to polarisation of optic emission exciting oil fluorescence, as per which anisotropy index of oil fluorescence is determined, as well as oil temperature is measured and oil dynamic viscosity is determined additionally as per the specified calibration dependence and oil operability is evaluated as per the ageing index, by comparing the index value to a threshold value, and as per the change of oil viscosity at its operating temperature relative to the threshold value. Besides, a device adapted for implementation of the above method is described.

EFFECT: improving reliability of effective monitoring of oil operability owing to increasing informativity by using for effective evaluation of oil state of two diagnostics indices - oil ageing degree characterising the change of oil chemical properties and oil viscosity characterising the ability of providing effective thickness of lubrication layer between surfaces of friction assemblies.

2 cl, 1 dwg, 3 tbl

Description

The invention relates to mechanical engineering and can be used to evaluate in real time the health of the oil, in particular hydraulic, compressor, transmission, engine oil, in order to determine the optimal timing of its replacement.

To ensure high reliability of the mechanisms, timely oil change, methods and devices are being developed that are built into the oil circulation line, allowing to obtain information about the state of the lubricant during the operation of machinery and equipment. At the same time, important requirements for such devices are the reliability of the design, the reliability of the information received and the small size.

One of the main factors in the deterioration of the working properties of oil is a change in its viscosity, which determines the ability of the oil to provide an effective thickness of the lubricant layer between the surfaces of the friction units, which prevents accelerated wear and disruption of the normal operation of the friction units. As an increase in viscosity, and its decrease leads to a violation of the bearing capacity of the oil. An increase in viscosity may indicate thermal degradation, oil oxidation, decomposition of additives, water pollution, etc. A decrease in viscosity may be caused by fuel entering the oil, cracking (at very high temperatures).

An equally important indicator of the health of the oil is its oxidation due to exposure to high temperature and its interaction with oxygen, nitrogen oxides and air moisture, as well as a decrease in the content of antioxidant additives during the operation of the mechanisms. As a result of oil oxidation, acids are formed that cause corrosion of the metal parts of the friction units and their premature failure.

Known methods and devices for the operational monitoring of the oil’s health by changing its viscosity, which are built into the lubrication system and provide continuous monitoring of the oil’s working properties in order to replace it in a timely manner.

The known method of a falling ball, based on measuring the speed of steady motion of a body in a test oil, is implemented in a device that uses two electromagnetic coils covering a piston made of ferromagnetic material (US patent No. 6584831, IPC: G01N 11/10, publ. 21.12 .2001). The device is integrated in the oil circulation line, and oil fills the measuring cavity. The electromagnetic coils are switched on alternately, creating a force causing the piston to move in both directions along the measuring cavity. As viscosity increases, piston movement slows down. The viscosity of the oil is estimated by the time the piston moves between the coils. Since the movement of the piston in both directions is forced, it is not affected by gravity and oil flow.

The disadvantage of this method and device is that it requires the use of macro displacement of the piston, which complicates the design, increases the size and reduces the reliability of the device due to wear of the rubbing parts.

Known quasistatic (without moving at the macro level) method and device for monitoring the viscosity of lubricating oil (Agoston A., Otsch C., Jakoby B. Viscosity sensors for engine oil condition monitoring - Application and interpretation of results // Sensors and Actuators - 2005 (121) , 327-332, US patent No. 6938462, IPC: G01N 11/00, publ. September 6, 05), which are based on measuring the parameters of acoustic waves passing through a crystal in contact with the test oil. The device consists of a thin AT quartz disk - a slice with two circular electrodes deposited on the end surfaces. A voltage is applied between the electrodes that causes a shear strain of the crystal. The oscillating surface generates a plane-parallel laminar flow in the contacting liquid layer. By changing the frequency of the applied voltage, the frequency of the mechanical resonance is found. The shift of the resonant frequency and the change in the amplitude of the oscillations provide information on the properties of the oil.

The disadvantage of this method is that due to the high operating frequency (> 5 MHz), it is sensitive to the properties of the liquid only in a very thin layer in contact with the surface of the sensor. In addition, when high-frequency elastic waves propagate through a viscous oil (high molecular weight liquid), the oil begins to behave like a gel, since the vibration frequencies of large molecules coincide or are less than the operating frequencies of the device. In this case, the device does not accurately reflect the viscosity properties of the oil.

Known methods and devices for operational monitoring of the health of the oil by changing the degree of its oxidation, built-in lubrication system.

So, it is known a device for monitoring the quality of oil (US patent No. 6459995, IPC: G01N 031/00, publ. 01.10.02), based on the measurement of changes in its dielectric constant. The device contains a capacitive sensor immersed in oil, which is an element of the oscillatory circuit containing an LC or crystal oscillator.

The output signal of the oscillatory circuit depends on the dielectric constant and the tangent of dielectric loss of oil, which change with a change in its acidity. Thus, the output signal carries information about the degree of oxidation of the oil. The disadvantage of this device is that the dielectric constant of the oil, and therefore the output signal, depends not only on the acidity of the oil, but also on the water content, the degree of contamination of the oil by mechanical particles, which makes it impossible to establish the main factor that caused the signal to change.

Optical, in particular fluorescent, operational methods for monitoring the quality of oil by the degree of its oxidation, also developed with the aim of increasing sensitivity by reducing electrical noise, are also known.

The closest technical solution (prototype) is a method and device for operational monitoring of the performance of lubricating oil (Patent RB No. 11208, IPC: G01N 33/26, publ. 30.06.08), based on measuring changes in the fluorescence parameters of the oil during its operation. A method for operational monitoring the performance of lubricating oil includes the following operations: a beam of optical radiation that excites fluorescence of the oil is directed to a controlled oil; measure the fluorescence intensity of fresh oil simultaneously in three spectral ranges and determine two working spectral ranges in which the intensities are greater than in the third; measure the fluorescence intensity during the operation of the oil; determine the rate of oil oxidation as a ratio of intensities in the working spectral ranges; by changing the rate of oxidation of the oil evaluate its performance in the friction units. The device consists of a housing with an optical window fixed in it, a transmitting channel that contains an emitter, a transmitting optical fiber and a feedback photodetector, a measuring channel including a receiving optical fiber and a color sensor, and a signal processing and decision block.

The disadvantage of the prototype is the lack of information about the state of the oil, since its assessment is carried out according to one diagnostic indicator - the degree of oxidation of the oil and its viscosity is not evaluated. Limited information content is the reason for the lack of accuracy and reliability of the assessment of the performance of the oil.

The objective of the invention is to increase the reliability of operational control of the oil’s performance by increasing the information content by using two diagnostic indicators for an effective assessment of the oil’s condition - the oxidation state of the oil, characterizing the change in the chemical properties of the oil, and the viscosity of the oil, characterizing the ability to provide an effective thickness of the lubricant layer between the surfaces friction units.

The problem is solved by the fact that the known method of operational monitoring the performance of lubricating oil, which consists in sending a beam of optical radiation that excites oil fluorescence to the controlled oil, measuring the fluorescence intensity of fresh oil simultaneously in three spectral ranges and determining two operating spectral ranges in which the intensities are greater than in the third, they measure the fluorescence intensity during the operation of the oil, determine the oxide oil ratio as a ratio of intensities in the working spectral ranges and according to the oxidation index evaluate the oil’s performance, supplemented by a new set of operations.

It is known (Lakowicz J.R. Principles of Fluorescence Spectroscopy. Second Edition. University of Maryland School of Medicine. Kluwer Academic / Plenum Publishers. New York. 1999) that fluorescence anisotropy depends on the viscosity of the medium in which the fluorescent molecules are located. This relationship is used in methods for measuring the viscosity of non-fluorescent body fluids (Williams AM, Dor Ben-Amotz. Molecular-Optical Viscometer Based on Fluorescence Depolarization / Anal. Chem. 1992, P.700-703) and polymeric materials (US Patent No. 5151748, IPC: G01N 11/00, published on September 29, 1992), for which purpose fluorescent "molecular rotors" or "chromophores" are introduced into the test medium. In this case, the viscosity η of the test medium η = f (r) is estimated from the change in the anisotropy of g fluorescence of molecular rotors. The lubricant contains fluorescent molecules of the base base and additives (mainly molecules of aromatic and polycyclic aromatic compounds), which does not require the introduction of special fluorescent markers for the use of fluorescent methods.

A new set of operations is that the optical radiation that excites the fluorescence of the oil is polarized so that it acquires a linear polarization, and additionally simultaneously measure the fluorescence intensities with parallel I _// (T) and perpendicular I _⊥ (T) polarization of radiation relative to polarization of optical radiation exciting oil fluorescence. In addition, the temperature T of the oil is recorded, which is an important operation, since the viscosity of the oil is highly dependent on temperature, therefore, when monitoring the viscosity, it is necessary to indicate at what temperature the measurements were made. From the measured intensities I _// (T) and I _⊥ (T), the anisotropy index r (T) of oil fluorescence at temperature T is determined by the formula (Levshin L.V., Saletsky AM Luminescence and its measurements: Molecular luminescence. - M. : Publishing House of Moscow State University, 1989. - 272 p.):

$$\text{r}\left(\text{T}\right)=\frac{{\text{I}}_{\text{//}}\left(\text{T}\right)-{\text{I}}_{\perp }\left(\text{T}\right)}{{\text{I}}_{\text{//}}\left(\text{T}\right)+{\text{2I}}_{\perp }\left(\text{T}\right)}\left(\text{one}\right)$$

and in addition to the indicator of oil oxidation, its dynamic viscosity is evaluated by the calibration dependence:

$$\text{η}=\varphi \left(\text{r}\text{, T}\right)\left(\text{2}\right)$$

Where

η is the dynamic viscosity,

r is the anisotropy index,

T is the temperature of the oil.

Then evaluate the performance of the oil by the oxidation index S of the oil, comparing the value of S with the threshold value of S _then , and by changing the viscosity η of the oil at its operating temperature relative to the threshold value of η _then .

The introduction of a new set of operations allows the use of an additional diagnostic indicator, the viscosity of the oil, for operational monitoring of the oil’s health, which increases the information content and, therefore, the reliability of the conclusion about the oil’s health.

The specified technical result in the implementation of the invention is achieved by the fact that in a known device comprising a housing with an optical window fixed therein, a transmitting channel consisting of an emitter, a transmitting optical fiber, a feedback photodetector, a measuring channel including a receiving optical fiber and a color sensor, and the signal processing and decision unit according to the invention, the transmitting channel further comprises a polarizer mounted between the transmitting optical fiber and the optical window, which serves to create a linear polarization of optical radiation that excites the fluorescence of the oil. In addition, the device contains two additional measuring channels, each of which contains a sequentially measuring photodetector, a receiving optical fiber and an analyzer installed between the receiving optical fiber and the optical window, the polarization plane of the analyzer of the first additional measuring channel being parallel and the second perpendicular to the plane of polarization . Additional measuring channels were introduced to measure simultaneously the fluorescence intensity with parallel I _// and perpendicular I _⊥ polarization of the radiation relative to the polarization of the exciting optical radiation, respectively. In addition, a temperature sensor is installed in the device’s body to measure the temperature of the monitored oil.

The invention is illustrated by drawings, which depict:

figure 1 - design of the proposed device;

figure 2 is a histogram of the change in the oxidation index S of the compressor oil during operation and the threshold value of the indicator S _then ;

figure 3 is a histogram of changes in viscosity η of compressor oil during operation and the threshold value of the indicator η _then .

The proposed device comprises a housing 14 with an optical window 10 fixed therein and a temperature sensor 19, a transmitting channel, three measuring channels and a signal processing and decision-making unit 17 (Fig. 1). The transmitting channel, which serves to create a linear polarization of optical radiation and transfer it to the volume of the controlled oil, consists of an emitter 1, a feedback photodetector 2, a transmitting optical fiber 5 and mounted on the surface of the optical window 10 of the polarizer 11, after passing through which the optical radiation acquires linear polarization. In this case, the input end face of the optical fiber 5 is facing the emitter 1, and the output end is facing the polarizer 11. The measuring channels are used to transmit the fluorescence radiation of the oil from the controlled oil region to the recording sensors. The first measuring channel includes a receiving optical fiber 6 and a color sensor 3. The input end face of the receiving optical fiber 6 is facing the optical window 10, and the output end is facing the color sensor 3. A color sensor detecting the fluorescence intensity of the oil simultaneously in three spectral ranges, in particular, “Red”, “green” and “blue” allows to evaluate the spectral distribution of fluorescence of oil, which is used to determine the oxidation index. The second measuring channel contains a first analyzer 12, a receiving optical fiber 9 and a photodetector 8. The third measuring channel contains a second analyzer 13, a receiving optical fiber 7 and a photodetector 4. The input ends of the transmitting optical fibers 9 and 7 are facing the analyzers 12, 13, and the output to the photodetectors 8 and 4, while the analyzers are mounted on the surface of the optical window so that the plane of polarization of the first analyzer 12 is parallel and the second analyzer 13 is perpendicular to the plane of polarization of the polarizer 11, that о allows using photodetectors 8 and 4 to register fluorescence with parallel and perpendicular polarization relative to the polarization of the optical radiation exciting the fluorescence. The electrical terminals of the emitter 1, the feedback photodetector 2, the color sensor 3, the photodetectors 4 and 8, and the temperature sensor 19 are output to a mounting plate 15 mounted on the housing 14 and connected by an electric cable 18 to the signal processing and decision unit 17. For protection against mechanical damage and shielding from electrical interference, a protective cover 16 is used, mounted on the housing 14.

As a radiation source, the proposed device uses a source of such radiation, which excites the fluorescence of the oil, i.e. with a wavelength in the range of 350-450 nm (for example, UV diode. LED3-UV-395-30). The color sensor allows you to simultaneously measure the fluorescence intensity of the oil in three spectral ranges, in particular, in “red”, “green” and “blue”. Such a sensor can be, for example, a Color Sensor MCS3AT / MCS3BT or Color Sensor TCS230. As measuring photodetectors 4, 8, a photodetector is used, the spectral sensitivity region of which is consistent with the fluorescence spectrum of lubricating oils, for example, a VTB8440 photodiode.

To evaluate the viscosity at the manufacturing stage, the device is calibrated in the laboratory using calibration samples with known viscosity at given temperatures. The obtained calibration dependence η = φ (r, T) is entered into the microprocessor memory of the device.

The proposed method is as follows.

The device using a thread and an o-ring 20 is mounted in a tank with a controlled oil, as shown in figure 1, or built into the oil pipe. The device is connected to power. Test equipment is filled with fresh oil. Part of the optical radiation flux of the emitter 1 is fed to a feedback photodetector 2, which measures the radiation intensity and its output signal is used in the feedback circuit to stabilize the radiation intensity of the emitter. The optical radiation beam of the emitter 1 passes through the optical transmitting fiber 5 to the polarizer 11, where it is converted from non-polarized to linearly polarized radiation, and then through the optical window 10 is directed to a controlled oil. In this case, fluorescence is excited in the irradiated volume of the oil. Part of the fluorescence radiation flux, passing through the optical window 10, is transmitted through the receiving optical fiber 6 to the color sensor 3, which registers the fluorescence intensity (I _R , I _G and I _B ) simultaneously in three spectral ranges - red "R", green "G" and blue "B". Then, from the three spectral ranges, two operating ranges Δλ _ld and Δλ _cor are determined, in which the intensities are greater than in the third. In the first measuring channel, the oxidation index S of oil is calculated by the formula

, $$\text{S}=\frac{{\text{I}}_{\text{Δλ}\text{dl}}}{{\text{I}}_{\text{Δλ}\text{core}}}$$

,

where I _Δλdl is the value of the fluorescence intensity measured in the long-wavelength

operating spectral range;

I _Δλcor is the fluorescence intensity value measured in the short-wavelength working spectral range.

During the operation of the equipment, oil oxidation occurs, which is accompanied by a shift of the fluorescence spectrum to the long-wavelength region and an increase in I _Δλ for relatively I _Δλcor , i.e. an increase in S.

The second part of the fluorescence radiation flux, passing through the optical window 10, falls on the first analyzer 12, the plane of polarization of which is parallel to the polarization plane of the polarizer 11, as a result of which fluorescence radiation with parallel I _// polarization relative to the polarization of the optical radiation is transmitted to the photodetector 8 through the receiving optical fiber 9, excitatory fluorescence.

At the same time, in the third measuring channel, the fluorescence radiation passes through the optical window 10, the second analyzer 13, the plane of polarization of which is perpendicular to the plane of polarization of the polarizer 11, and transmitted through fiber 7 to the photodetector 4, which detects fluorescence with perpendicular I _⊥ polarization of radiation relative to the polarization of optical radiation, which stimulates fluorescence of oil. Also, at the same time, the temperature sensor 19 detects the oil temperature T.

Then, the anisotropy index of oil fluorescence is determined by the formula (1) and the dynamic viscosity of the oil is calculated from the calibration dependence η = φ (r, T).

After that, the performance of the oil is evaluated by the oxidation index S, comparing the value of S with the threshold value of S _then , and by changing the viscosity η of the oil at its operating temperature relative to the threshold value of η _then .

All calculations are performed using a microprocessor in the signal processing unit. The values of S, η and T are displayed on the display of the device. The values of the indicators S and η are compared with threshold values and a conclusion is made on the performance of the lubricating oil in the decision block, which is reflected by the light indication on the display.

The introduction of two additional measuring channels allows simultaneous measurements of fluorescence intensity with parallel I _// and perpendicular I _⊥ polarization of radiation relative to the polarization of exciting optical radiation, respectively. This makes it possible to evaluate the anisotropy of the fluorescence of the oil and an additional parameter characterizing the performance of the oil, the viscosity of the oil. In addition, a temperature sensor installed in the device’s body makes it possible to record the operating temperature of the controlled oil, which is an important parameter in the analysis of the oil and is used to determine its viscosity.

As a result of assessing the condition of the oil simultaneously by two diagnostic indicators - the degree of oxidation of the oil and the viscosity of the oil - increases the information content of the analysis and the reliability of the conclusion about the health of the oil.

An example of the use of the proposed method and device for monitoring the health of the oil KS-19 in the compressor system.

To assess the viscosity, the device at the manufacturing stage was calibrated under laboratory conditions using oil samples (NAFTAN MI 1-3 (SAE 15W-40) and Shell Omala Oil 460) with known viscosity at given temperatures. The obtained calibration dependence η = φ (r, T) has the form:

$$\text{η}\left(\text{r}\text{,}\text{T}\right)=\text{A}\left(\text{T}\right)\cdot \text{r}\left(\text{T}\right)-\text{B}\left(\text{T}\right)\text{,}\left(\text{3}\right)$$

Where

A (T) = 56.69 · exp (-0.0605 · T) and B (T) = 5.4103 · exp (-0.0726 · T) are temperature coefficients.

The calibration dependence was recorded in the memory of the microprocessor of the device.

так как $$\text{S}=\frac{{\text{I}}_{\text{Δλдл}}}{{\text{I}}_{\text{Δλкор}}}=\frac{{\text{U}}_{\text{G}}}{{\text{U}}_{\text{B}}}$$

Одновременно измерялись сигналы на выходе фотоприемника второго U_// и третьего U_⊥ измерительных каналов, отражающие соответственно интенсивности флуоресценции с параллельной I_// и перпендикулярной I_⊥ поляризацией, по которым определяется показатель анизотропии г при измеренной температуре Т:To control the performance of lubricating oil KS-19 in the compressor system, the proposed device was installed in a tank with oil. The lubrication system was filled with clean oil KS-19 and the device for monitoring the performance of lubricating oil was turned on. At the output of the color sensor, which was used as the Color Sensor MCS3AT / MCS3BT, three signals (U _R = 164 mV, U _G = 636 mV and U _B = 1246 mV) were recorded simultaneously using the microcontroller of the processing and decision unit fluorescence of oil (I _R , I _G and I _B ) in red “R”, green “G” and blue “B” spectral range. Further signal processing was also performed using a microcontroller. Namely, it was determined that the minimum value of the three signals (U _R , U _G and U _B ) is the signal in the red spectral range, that is, the working spectral ranges are green and blue, and IΔλ _for = I _G , IΔλcor = I _B . Therefore, the oxidation index S when assessing 10 oil KS-19 was determined as the ratio $$\frac{{\text{U}}_{\text{G}}}{{\text{U}}_{\text{B}}}$$

as $$\text{S}=\frac{{\text{I}}_{\text{Δλ for}}}{{\text{I}}_{\text{Δλcor}}}=\frac{{\text{U}}_{\text{G}}}{{\text{U}}_{\text{B}}}$$

At the same time, the signals at the output of the photodetector of the second U _// and third U _⊥ measuring channels were measured, reflecting respectively the fluorescence intensities with parallel I _// and perpendicular I _⊥ polarizations, which determine the anisotropy index g at the measured temperature T:

$$r\left(T\right)=\frac{I_{//}\left(T\right)-I_{\perp }\left(T\right)}{I_{//}\left(T\right)+2I_{\perp }\left(T\right)}=\frac{U_{//}\left(T\right)-U_{\perp }\left(T\right)}{U_{//}\left(T\right)+2U_{\perp }\left(T\right)}$$

Using the value of the anisotropy index r taking into account the oil temperature, its dynamic viscosity η was determined from the calibration dependence (3).

The table shows the measured values of the signals U _R , U _G , U _B , U _// , U _⊥ and T, as well as the calculated values of S, r and η for fresh oil (operating time t = 0) and for oil operating in the compressor system during time t1 and t2.

Table oil operating time t = 0 t1 t2 U _R , mV 164 128 44 U _G , mV 636 350 96 U _B , mV 1246 580 113 S 0.51 0.60 0.85 U _// , mV 391 273 94 U _⊥ , mV 294 201 66 r 0,099 0.107 0.124 T, ° C 60 61 60 η, Pa s 0,079 0,086 0.117

Figure 2 and figure 3 shows the change in the oxidation index S and viscosity η of oil during operation and their threshold values of S _then and η _then . It is seen that the values of the diagnostic indicator S during the operating time on the graph did not exceed the threshold, while the viscosity of the oil when the operating time t2 exceeds the threshold value η _pore = 0.11 Pa · s, while a warning signal appeared on the display the need for an oil change (the indicator LED of the signal processing and decision-making unit was turned on).

The above example shows that the proposed method and device that implements the simultaneous assessment of two diagnostic indicators S and η increases the reliability of operational monitoring of the performance of lubricating oil by increasing the information content by using two diagnostic indicators at the same time to assess the condition of the oil - the degree of oil oxidation characterizing the change in the chemical properties of the oil , and the viscosity of the oil, characterizing the ability to provide an effective thickness of the lubricant layer between the surface tyami friction units.

Information sources

1. US patent No. 6584831, IPC: G01N 11/10, publ. 12/21/2001.

2. Agoston A., Otsch S., Jakoby B. Viscosity sensors for engine oil condition monitoring - Application and interpretation of results // Sensors and Actuators - 2005 (121), P.327-332

3. US patent No. 6938462, IPC: G01N 11/00, publ. 09/06/05.

4. US Patent No. 6459995, IPC: G01N 031/00, publ. 10/01/02.

5. Patent RB No. 11208, IPC: G01N 33/26, publ. 06/30/08 (prototype).

6. Levshin L.V., Saletsky A.M. Luminescence and its measurements: Molecular luminescence. - M.: Publishing House of Moscow State University, 1989 .-- 272 p.

7. Lakowicz J.R. Principles of Fluorescence Spectroscopy. Second Edition. University of Maryland School of Medicine. Kluwer Academic / Plenum Publishers. New York 1999.

8. Williams A.M., Dor Ben-Amotz. Molecular-Optical Viscometer Based on Fluorescence Depolarization / Anal. Chem. - 1992, P.700-703.

Claims (2)

1. A method for operational monitoring the performance of lubricating oil, which consists in sending a beam of optical radiation that stimulates fluorescence of the oil to the controlled oil, measuring the fluorescence intensity of fresh oil simultaneously in three spectral ranges and determining two operating spectral ranges in which the intensities are greater than in the third, measure the fluorescence intensity during the operation of the oil, determine the rate of oil oxidation as the ratio of intensities in their spectral ranges and oxidation index evaluate the performance of the oil, characterized in that the optical radiation that excites the fluorescence of the oil is polarized and, at the same time, the fluorescence intensities are measured with parallel and perpendicular polarization of the radiation relative to the polarization of the optical radiation exciting the fluorescence of the oil, which determine the anisotropy index oil, and also measure the temperature of the oil and additionally determine the dynamic viscosity s oil on the calibration curve
η = φ (r, T),
where η is the dynamic viscosity,
r is the anisotropy index,
T is the oil temperature,
and evaluate the performance of the oil in terms of oxidation, comparing the value of the indicator with a threshold value, and by changing the viscosity of the oil at its operating temperature relative to the threshold value. 2. A device for operational monitoring the performance of lubricating oil, comprising a housing with an optical window fixed therein, a transmitting channel consisting of an emitter, a transmitting optical fiber, a feedback photodetector, a measuring channel including a receiving optical fiber and a color sensor, and a signal processing unit and decision making, characterized in that a temperature sensor is installed in the housing, and the transmitting channel comprises a polarizer installed between the transmitting optical fiber and the optical window, and, cr IU it comprises two additional measuring channels, each of which comprises, arranged sequentially measuring light detector receiving the optical fiber and the analyzer arranged between the receiving optical fiber and an optical window, wherein the plane of the analyzer of the first additional measuring channel polarization parallel, and the second perpendicular plane polarizer polarization.

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