RU2207556C1 - Procedure establishing quality of mineral motor oils and causes of its change - Google Patents

Abstract

FIELD: diagnostics of change of initial state of liquid substance and establishment of causes of these changes. SUBSTANCE: values of electric conductivity and dielectric permittivity of reference and tested specimens are measured at given temperature from 10 to 90 C. Oil is good for running if it satisfies condition 1<n<n_crit where n and n_crit are ratios of electric conductivity of reference and tested oils and of reference oil and oil unsuitable for running. If n≥n_crit it is advised that oil is object should be replaced. Causes of change of oil quality are established by ratio of dielectric permittivities of reference and tested oils. EFFECT: reliable, timely establishment of degree of suitability of oils for running without consumption of various resources, analysis of oils right in operated objects.

Description

 The invention relates to the field of diagnosing changes in the initial state of a liquid substance and determining the causes of these changes. It can be used to solve a wide range of problems of analyzing the quality of fuels and lubricants in motor vehicles, locomotives, sea and river vessels, in aviation, turbogenerators, transformers and energy distributors, in transmission systems, in oil refining, when used in various types of motors, hydraulic systems in the production and regeneration of oils.

 Currently, during the operation of oils, there are practically no affordable, fast, reliable and effective ways to determine the quality of the oil before changing it. The criterion (analogue) for replacing the oil is the average service life in kilometers or hours of operation of the cars, the duration of operation in various engines or plants, etc., established as a result of research and generalization of operating experience [1].

 In the production of oils, to assess their quality, analysis is carried out using numerous labor-intensive, time-consuming chemical methods [1]. Analyzes are carried out systematically with large material and intellectual costs.

 Low efficiency of quality assessment is negatively reflected in the operation of oils, it can lead to unforeseen expenses, environmental pollution with toxic combustion products.

 The operational determination of the quality of the oil using the proposed method coordinates the intervals for its replacement, which are necessary for actual operating conditions, thereby expanding the allowable operating intervals and increasing the life of the engine.

 The usefulness and effectiveness of the invention goes beyond simply informing about the need to change the oil. In some cases, for example, in aeronautical engineering, where safety is the main concern, or on large ships, locomotives and turbine units, where the cost of repairs is significant, the invention can provide early detection of an emergency.

The advantage of the proposed method is that it allows the generalized selective parameters n and n _e reliably, quickly, without the cost of reagents, without resorting to time-consuming, multi-factor and multi-operation chemical analyzes, to determine the degree of suitability of the oils for use, and also that their analysis can be carried out directly at numerous, very different facilities, in diagnostic inspection services that monitor the condition of oils at these facilities.

 The essence of the present invention is as follows.

Measured at a given temperature in the range from 10 to 90 ^o With the values of electrical conductivity and dielectric constant of the reference oil and the test oil, used, calculate the ratio of these values, and the oil quality is determined by the formula:
1 <n <n _{the critical eskoe,}
where n is the ratio of the electrical conductivity of the reference and test oil;
n _{the critical eskoe} - ratio of electric conductivities and the degraded model (limited usefulness) for operation oil.

The reasons for the change in the quality of the oil are selectively established by the formulas for n _ε - the ratio of the dielectric constant of the reference and test oils:
n _ε <1, if water gets into the oil;
n _ε > 1, if gasoline gets into the oil;
n _ε = 1 ± 0.05 corresponds to the condition due to the burnup of additives admissible for operation and slight pollution, in contrast to the above reasons (the presence of water and gasoline).

If _{the critical} n≥n _eskoe, oil the object it is advisable to replace.

 The invention is implemented as follows.

где G и G* - соответственно активные электропроводности образцового и отработанного масел. См;

- соответственно удельные электропроводности образцового и отработанного масел, См/м.Is set (determined) in the temperature range from 10 to 90 ^o C _{the critical eskoe} n - limiting criteria applications (limited usefulness) of an oil, which is a ratio of electric conductivities of the exemplary oil corresponding source performance standards and oils, used and already unserviceable:

where G and G * are respectively the active conductivities of the reference and waste oils. Cm;

- respectively, the electrical conductivity of the reference and waste oils, S / m

The electrical conductivity of the test oil is measured and, at a given temperature t, n is determined as the ratio of the model electrical conductivity to a given measured value. The oil is suitable for use if the condition:
1 <n <n _{the critical eskoe.}

When _{the critical} n≥n _eskoe advisable to change the oil, since its further exploitation may cause accidents, looming environmental and other problems.

 Note an important fact.

где К - геометрическая постоянная датчика, 1/м;
К* - приведенная постоянная датчика, 1/м.With a change in the conductivity, there may be a difference in the interaction of the liquid substance with the sensor. Then, to determine the quality change, instead of the G / G * ratio, use the formula given in [2]:

where K is the geometric constant of the sensor, 1 / m;
K * - reduced sensor constant, 1 / m.

 Under the condition K = K *, this difference in the interaction is not observed. For the capacitive sensor used in our case, which has two potential electrodes equipped with a screen with zero potential, which is connected using a three-clamp circuit, the oil-sensor interaction remains the same in the entire measured range, i.e. K = K *.

At the same time, the causality criterion n _ε is established (determined) at a given temperature, which is the ratio of the dielectric constants of the reference and analyzed oils.

If n _ε <1 - water is present in the oil;
if n _ε > 1 - gasoline is present in the oil.

 Examples of specific performance.

Oil brands were analyzed:
M8B manufactured in Russia;
SAEW5 - 30 - made in the USA.

 1. Measurements of electrical conductivity and permittivity are carried out using an E7-14 immitance meter complete with a capacitive DP sensor attached to it [3].

Connect the sensor to the device E7-14 and determine its electric capacity with air:
C _o = 8.98 pF.

Example 1. Analysis of oil brand M8B
2. The gauge is filled alternately with exemplary, and then unsuitable for use oil, and at a given temperature of 20 ^° C, the active conductivities G — for exemplary and G * —for used oil are determined using an instrument, and electrical capacitances C — for exemplary and C * - for waste oils:
G = 12.03 • 10 ^-9 cm; C = 21.38 pF;
G * = 4.29 • 10 ^-9 cm; C * = 22.53 pF.

3. Determine at 20 ^o With the ultimate criterion for the suitability of the oil for use:
n _{Critical eskoe} = G / G * = 2,80.

4. Fill the sensor with the test oil and at 20 ^o With the help of the device determine the active conductivity
G _m = 7.7 • 10 ^-9 cm
and electrical capacitance
C _m = 22.49pF.

5. Determine at 20 ^o With the value of the quality criterion for the analyzed oil n = 1,56.

It turned out that n <n _{the critical eskoe.} Therefore, the oil is serviceable. The causality criterion is determined n _ε = 0.95 - the oil does not contain water and gasoline.

Example 2. Analysis of brand SAEW5-30 oil
Using an E7-14 immitance meter complete with a DP sensor, as in example 1, p. 1, С _о = 8.98 pF is measured.

1. Alternately fill the sensor with an exemplary one, and then with oil after a run of 11,000 km and at a temperature of 20 ^o С, determine with the help of a device the corresponding active conductivities G - for a model and G * - for oil after a run of 11,000 km, as well as electric capacitances C - for a model and С * - for oil after a run of 11,000 km:
G = 30.02 • 10 ^-9 cm; C = 21.08 pF;
G * = 17.14 • 10 ^-9 cm; C * = 21.87 pF.

3. Determine at 20 ^o With in this case the ultimate criterion for the suitability of the oil for use:
n _{Critical eskoe} = G / G * = 1,75.

4. Fill the sensor with the test oil and at 20 ^o With the help of the device determine the active conductivity
G _m = 7.37 • 10 ^-9 cm
and electrical capacitance
Cm = 22.36 pF.

5. Determine at 20 ^o With the value of the quality criterion for the analyzed oil n = 4,07.

It turned out that n = 4,07> n _{the critical eskoe.} Therefore, the oil is unusable.

The causality criterion is determined n _ε = 0.94 <1.0 - water got into the oil.

Literature
1. Kolesnik P. A. Material science in road transport. - M .: "Transport", 1980.

 2. Usikov S. V., Babkin P. A., Ivanova Z. D., Feofilatyeva R. N. The method for determining the electrical conductivity of the liquid / A.s. 1423950, 1988 /.

 3. Belousov O. A., Efremov B. M., Leonov V. M., Litko A. A., Lukina T. A., Ovinnikov V. K., Solodova M. P., Usikov S. V. Three-electrode sensor / A.s. 578603, 1977. Bull. 40 /.

Claims (1)

The method of determining the quality of mineral motor oils and the reasons for its changes, characterized in that at a given temperature in the range from 10 to 90 ^o C determine the ratio of electrical conductivity and dielectric constant of the reference and test oils, the oil quality is determined by the formula
1 <n <n _{of critical,}
where n is the ratio of the electrical conductivity of the reference and test oils;
n _{crit nical} - ratio of electric conductivities and an exemplary unserviceable oil and causes changes in quality of oil set by the formulas
n _ε <1 - water got into the oil;
n _ε > 1 - gasoline got into the oil,
where n _ε is the ratio of the dielectric constant of the reference and studied oils.