RU2199114C1 - Device evaluating service properties of motor oils - Google Patents

Abstract

FIELD: evaluation of service properties of motor oils. SUBSTANCE: invention deals with facilities for motor oil oxidation while evaluating oil service properties. Device evaluating service properties of motor oils includes working chamber with electric heating, spray gun, cooler for volatile products of oxidation with return of condensate and temperature meter. Working chamber comes in the form of cylindrical separable barrel mounted for leak-tight fixing, upper part of barrel carries separable bushing, spray gun comes in the form of hollow cone which vertex has hole and is dipped into examined motor oil. Holes to pulverize oil are drilled in opposition to separable busing, near base of spray gun. Spray gun is installed inside barrel uniaxially to it and is put on shaft which is supported in bearings. Bubbling tube meant to supply oxidizer and to take oil samples for analysis from barrel by means of suction unit is positioned under spray gun. Cooler for volatile products of oxidation is mounted above working chamber and has form of hollow cylinder with inlet and outlet pipe unions for cooling agent and flanges. Lower flange forms conical surface which vertex is directed inward of cooler and upper flange is closed by lid that is joined tight to lower flange. EFFECT: potential for determination of temperature region of serviceability of motor oil, of rate of its oxidation and of 3 dwg its corrosion activity depending on time and temperature of test.

Description

 The invention relates to devices for the oxidation of oils in the evaluation of operational properties.

A universal oxidation apparatus is known (GOST 18136 - 72, p. 2 - 4), which includes an aluminum heating block, inside of which there are six nests - pockets for placing test vessels. The block is heated using electric heaters that maintain a temperature of 40 to 250 ^o C with an accuracy of ± 0.5 ^o C. Test vessels are made of heat-resistant glass and include a refrigerator, a gas supply pipe, a condensate trap, a sleeve with a thin section, a transition tube, and a hook for catalyst suspension, capillary and test tube.

 The apparatus provides for the oxidation of the test oil with air or oxygen in the presence or absence of a catalyst at a given temperature. The stability of the oil against oxidation is characterized by the following indicators: acid number, saponification number, viscosity, resin content, coking ability, insoluble sediment content, dielectric loss tangent, volume resistivity, color and weight of the catalyst, appearance, color and mass of condensate.

 A disadvantage of the known technical solution is that the use of the apparatus does not provide for the possibility of determining the temperature range of the health of lubricating oils and their oxidation rate depending on changes in the temperature of the test.

 The closest in technical essence and the achieved result is a device for evaluating the operational properties of motor oils, including a working chamber made in the form of a cylindrical tube with electric heating, a sprayer made in the form of a tube mounted at an angle to the working chamber with an oil nozzle, a collecting tank, an external bath with electric heating, a refrigerator for volatile oxidation products, a condensate return pipe and a contact thermometer (ed. St. USSR 179083, G 01 N 33/28, G 01 N 25/14, 1966).

 A disadvantage of the known technical solution is that the use of air for spraying oil and the quality of its spraying depends on its viscosity (or temperature), air flow, and getting it into the working chamber reduces its temperature, which negatively affects the assessment of oil oxidation. In addition, it is not possible by the known device to determine the temperature range of the oil’s working capacity in which it is practically not oxidized, the oxidation rate used to evaluate the oil’s service life, and corrosion activity.

 The objective of the invention is to provide a device for determining the temperature range of the health of engine oil, its oxidation rate and corrosion activity depending on the time and temperature of the test.

 The problem is solved in that in the device for evaluating the operational properties of motor oils, including a working chamber with electric heating, a sprayer, a refrigerator for volatile oxidation products with condensate return and a temperature meter, according to the invention, the working chamber is made in the form of a cylindrical removable cup installed with the possibility of hermetic fixation, on the upper part of which a removable sleeve is placed, the sprinkler is made in the form of a hollow cone, the top of which has a hole and a bogie oil into the test oil, holes for spraying oil are made at the base of the sprayer against the removable sleeve of the glass, while the sprayer is placed coaxially with it and mounted on a shaft mounted in turn in bearings, a bubbler tube is installed under the sprayer, which is capable of supplying an oxidizing agent and sampling oil from a glass for analysis, using a suction device, a refrigerator for volatile oxidation products is installed above the working chamber and is made in the form of a hollow cylinder with refrigerant inlet and outlet fittings and flanges, the lower of which is made with the formation of a conical surface with the apex directed inside the refrigerator, and the upper one is tightly closed by a lid that is tightly connected to the lower flange.

 A comparative analysis of the prototype and the claimed device showed that the latter has the following distinctive features.

 The implementation of the working chamber in the form of a removable cup with a removable sleeve installed in it, supplying the device with a sprayer that turns the oil into a finely dispersed phase, and a bubbler tube for supplying oxidizer and a device for sampling the test oil, installing a refrigerator above the working chamber, which drains the condensate into the glass, and supplying the device with an oxidizer drain tube - all these design features are aimed at solving the problem - assessing the operational properties of motor oil by definition: temperature region of engine oil performance, speed of oxidation and corrosion activity depending on the time and temperature tests.

 In FIG. 1 shows a general view of the device; figure 2 - dependence of the rate of oxidation of oil on temperature; figure 3 - dependence of the oxidation index on the time of oxidation.

 The device contains three units hermetically connected to each other. In the lower block there is a working chamber for the test oil, made in the form of a cylindrical removable cup 1, mounted coaxially in the housing 2 of the electric heater 3, insulated from the environment by thermal insulation 4 and hermetically fixed by a clamping device 5. On the top of the cup 1 there is a removable sleeve 6, designed to study the tendency of oils to laconic agar formation and corrosion activity. Moreover, to study the varnish and carbon formation, the sleeve 6 is made of aluminum, and to determine the corrosion activity of oils and accelerate the oxidation process is made of steel, copper or its alloys.

 The cup 1 is removed from the housing 2 of the electric heater using the handle 7 during the extraction of the device 5. Inside the cup 1, a sprinkler 8 is coaxially mounted, made in the form of a hollow cone with an opening 9 at the top, which is immersed in the test oil. At the base of the sprayer 8, holes 10 are made for spraying oil onto the removable sleeve 6. Under the sprayer 8, which acts as a mixer, to provide a constant temperature in the volume of the test oil, a bubbler tube 11 for supplying an oxidizing agent (air) and a thermocouple 12 are installed.

 The bubbling tube 11 is connected to the compressor 13 by a flow meter 14, an oxidizing agent supply regulator 15, and an oil sampling device 16 during the test.

 The thermocouple 12 is connected to a temperature control unit 17, including: a temperature setter, a comparison, registration and indication circuit and connected to a heater 3. Unit 17 provides a discrete setting of the required temperature and its automatic maintenance during the test oil’s test time. The middle unit of the device is made in the form of a hollow cylinder 18 with holes for entering the bubbler tube 11, the sealed inlet 19 of the thermocouple 12 and the air outlet tube 20.

 The upper block is a refrigerator, it is a hollow cylinder 21 with an inlet 22 and an outlet 23 for supplying and discharging refrigerant (water) and two flanges, the lower of which 24 is made with a conical surface 25, the apex of which is directed inside the cylinder 21. Such a structural embodiment of the lower flange 24 provides condensation of oil vapors and drainage of condensate into the working chamber 1. On the cylindrical sleeve 26, made integral with the flange 24, the bearing 27 of the shaft 28 of the sprayer 8 is installed.

 The upper flange 29 of the cylinder 21 is hermetically closed by a cover 30 made with an upper sleeve 31 in which the electric drive 32 is installed and a lower sleeve 33 in which the bearing 34 of the shaft 28 of the sprayer 8 is installed. The bushings 26 and 33 are hermetically connected and thereby prevent the ingress of refrigerant into the working chamber 1 and provide normal temperature operation of the bearings 27 and 34.

 The device operates as follows.

 Due to the fact that the performance properties of oils are evaluated by such indicators as: temperature range of oil performance, oxidation rate, corrosion activity and varnish and carbon formation, we will consider the operation of the device taking into account the definition of these indicators.

To determine the temperature range of the health of the test oil, tests are carried out in the temperature range from 50 to 180 ^o C through the interval 10-20 ^o C for two hours for each temperature. Before the test, the oil is photometric and the absorbance is determined.

 The working chamber 1 is filled with the investigated oil in a volume of 100 g and, using the handle 7, is installed in the housing 2 of the electric heater 3 and hermetically fixed with a clamping device 5.

 The supply of refrigerant (water) is turned on, which, through the inlet fitting 22, the hollow cylinder 21 enters the outlet fitting 23. At the same time, the electric heater 3 is connected, connected to the block 17, by which the required temperature of the test oil detected by thermocouple 12 is set using the dial indicator. during the test it is supported automatically and is registered with a dial indicator.

 After reaching the set temperature, the indicator of operation of the heater 3 (LED) and the heater itself turn off, the compressor 13 is turned on, and using the valve 15, the oxidizer flow rate is established by the flow meter 14 and the test start time is fixed. At the same time as the compressor 13 is turned on, the sprinkler 8 rotational drive 32 is turned on, which, when rotated by centrifugal forces, pumps oil with an oxidizing agent through the opening 9 along the conical surface to the holes 10 to turn it into a finely dispersed state.

 The oxidizing agent (air) from the compressor 13 through the supply regulator 15, the flow meter 14 enters the bubbler tube 11 and through its holes immersed in oil passes through the volume of oil in the working chamber 1 and through the layer of the finely dispersed oil phase formed by its spraying, the holes 10 enter in contact with the cold conical surface 25 of the flange 24 of the refrigerator 21. After condensation of the oil vapor, the oxidizer through the tube 20 enters the atmosphere, and the condensate flows down the conical surface 25 into the working chamber 1 to continue oxidation.

 The interaction of the oxidizing agent with the oil in the volume, on the inner conical surface of the sprayer 8, with the finely dispersed phase and in a thin layer of oil flowing down along the surface of the removable sleeve 6, provides an increase in the contact time of the oxidizing agent with the oil, which increases its oxidation rate, and hence the test time.

After two hours of testing, the compressor 13 is turned off, the valve 15 is closed and, using the device 16 (syringe), an oil sample is taken and its optical density is determined. Then a new temperature value is set (10-20 ^o C higher than the previous one), the compressor 13 is turned on, the oxidizer consumption is set, and after reaching the set temperature, the time for starting the oil test under new temperature conditions is fixed.

 The tests are carried out until at a certain temperature there is a sharp change in the optical density of the test oil. This temperature is the limiting temperature of the tested oil. According to the test results, the dependences of the change in the optical density of the oil on the test temperature are built (Fig. 2).

According to the dependencies (figure 2), the temperature range of the health of the oil M-8-B (s) is limited to a temperature of 150 ^o C, and the oil 10 W 30 - 160 ^o C.

 After the test, the pressing device 5 is unscrewed, the handle 1 is removed with the handle 7, the test oil is drained, the glass is rinsed, filled with washing liquid and installed in the housing 2 of the heater 3. Then the spray nozzle 8 for washing is washed and the bubble tube 11 and the oil sampling device 16 are washed .

The operation of the device in determining the rate of oil oxidation is similar to that described above, with the only difference being that the oxidation is carried out at a constant temperature of 5-10 ^o C above the temperature of the onset of oxidation, determined by the dependences of FIG. 2, or at the temperature specified in the technical specifications for the oil test.

 After reaching the set temperature, the compressor 13 is turned on, the predetermined oxidizer flow rate is set by the valve 15 along the flow meter 14, the sprayer 8 is turned on and the time of the oxidation start is fixed. Every two hours, an oil sample is taken by the device 16 for photometry and determining the degree of oxidation. The obtained values of the optical density are used to build the dependence (Fig. 3) on the oxidation time, according to the slope of which the oxidation rate is determined. The lower the rate of oil oxidation, the higher its thermo-oxidative stability.

 According to the data (figure 3) the lowest oxidation rate has oil 10 W 30, and the highest - M-8-B (s). So, for example, an oxidation index of 0.3, oil M-8-B (s) reaches in 4.7 hours, oil M-8-B in 5.6 hours, and oil 10 W 30 in 16, 4 hours, so oil 10 W 30 has the greatest resource.

The work of the device to determine the tendency of oil to varnish and carbon formation is similar to that described with the only difference that the oil is tested in the temperature range from 180 to 350 ^o C. In this case, the initial temperature is set to 180 ^o C and increase its value stepwise by 10-20 ^o C , and the test time is increased to 4 hours

 Before testing, the removable sleeve 6, made of aluminum or its alloys, is weighed with an accuracy of 0.002 g. After every 4 hours of testing, the cup 1 is removed from the housing 2 of the heater 3, the sleeve 6 is removed, degreased, dried, weighed and the amount of deposits is determined depending on the temperature tests.

 To determine the corrosion activity of the test oil, the removable sleeve 6 is used from steel, copper or its alloys, and the corrosion activity is determined by the difference in its weight before and after the test. The same removable bushings are used as catalysts to increase the rate of oil oxidation.

 Using the device allows testing both pure and working oils, both with and without a catalyst, and to evaluate the performance properties of motor oils by indicators such as: temperature range of performance, oxidation rate, corrosion activity and a tendency to varnish and carbon formation That allows you to select the best samples of oils and evaluate the change in their operational properties when used in internal combustion engines.

Claims (1)

 A device for evaluating the performance properties of motor oils, including a working chamber with electric heating, a sprayer, a refrigerator for volatile oxidation products with condensate return and a temperature meter, characterized in that the working chamber is made in the form of a cylindrical removable cup mounted with the possibility of hermetic fixation on the upper part which has a removable sleeve, the sprayer is made in the form of a hollow cone, the top of which has a hole and is immersed in the test oil, at the base openings for spraying oil are made against the spray nozzle against the removable sleeve of the glass, while the spray is placed coaxially into the glass and mounted on a shaft mounted in turn in the bearings, a sparging tube is installed under the spray, made with the possibility of feeding an oxidizing agent and sampling the oil from the glass for analysis using a suction device, a refrigerator for volatile oxidation products is installed above the working chamber and is made in the form of a hollow cylinder with inlet and outlet fittings for refrigerant and flanges, the lower of which is made with the formation of a conical surface with the apex directed into the inside of the refrigerator, and the upper one is hermetically closed by a lid, which is sealed to the lower flange.

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