RU2477308C1 - Hydraulic fluid for automatic transmission - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to compositions of hydraulic fluids used in automatic transmission. Improvements are achieved by adding isomerised slack wax (fraction 360°C - K.K) to an oil base which is a low-viscosity distillate component. The low-viscosity distillate component is obtained from vacuum distillate of a crude oil distillation plant (fraction 300-450°C) through selective purification, dewaxing and hydrofining. The isomerised slack wax (fraction 360°C - K.K) is obtained by a catalytic method from petroleum slack wax - a by-product of plants for dewaxing refined oil (fraction 300°C - K.K) with oil content of 2.5-12 wt % by hydrofining, hydroisodewaxing, hydrogenation with subsequent fractionation. The isomerised slack wax has kinematic viscosity at 100°C in the range of 3.9-4.7 mm²/s, chilling point not higher than minus 10°C and open flash point not lower than 210°C. Components of the hydraulic fluid for automatic transmission are in the following ratio, wt %: multifunctional additive (antiwear, antioxidant, friction modifier, viscosity modifier) 14-18; anticorrosion additive 0.06-0.1; antifoam agent 0.002-0.006, dye 0.002-0.003, base - up to 100, wherein the base contains, wt %: a low-viscosity distillate component - 20-70; isomerised slack wax - 30-80.

EFFECT: improved viscosity-temperature characteristics: low dynamic viscosity at minus 40°C, higher viscosity index, low chilling point, reduced susceptibility to foaming.

1 cl, 4 tbl, 1 ex

Description

The invention relates to compositions of hydraulic fluids used in automatic transmissions.

Hydraulic fluids for automatic transmissions are a special type of hydraulic fluid. Since automatic transmissions include several completely dissimilar units - a torque converter, a gearbox, a complex control system, a hydraulic fluid must have the following functions: lubricate, cool, transmit torque and contribute to friction clutch.

The following basic requirements for the quality of fluids for automatic transmission can be noted:

- the static and dynamic coefficients of friction must be stable during the period of operation of the fluid;

- good low temperature properties;

- high viscosity index;

- good antiwear properties;

- high resistance to oxidation at high temperature and vigorous mixing with air;

- good dispersing and washing properties;

- good anti-corrosion properties;

- low foaming and good deaeration.

Automatic transmission fluids are well-refined and specially selected mineral or synthetic oils with additives that give the oil the required properties. The static and dynamic coefficients of friction should have constant values during the entire operation to ensure easy gear shifting and avoid jerking during transmission operation. Smooth operation of the transmission without jerking is ensured by the use of friction modifiers, which are introduced into almost all fluids of hydrodynamic gears and are of particular importance for fluids of an automatic transmission. High viscosity index is provided by specially selected basic mineral or synthetic bases and viscosity index modifiers. Foaming should be minimal at the highest speeds and loads. Antioxidant resistance should ensure the stability of the properties of the oil during the entire period of operation of the oil (30000-50000 km). To improve lubricating properties, antiwear additives are introduced.

The aim of the present invention is to provide a hydraulic fluid for automatic transmissions with improved viscosity-temperature characteristics, minimum dynamic viscosity at sub-zero temperatures, improved anti-foam properties.

Known oil for automatic transmissions [1 - US 4,758,364], having the following composition, wt.%:

the monoolefin polymer C ₂ -C ₁₀ - 15.

a copolymer of methacrylic acid ester with C ₁ -C ₁₈ saturated monovalent monohydric alcohol - 5;

base base (mineral and synthetic) - up to 100.

The specified invention is aimed at improving shear rate and viscosity-temperature characteristics. However, in comparison with the claimed, the dynamic viscosity at minus 40 ° C is significantly higher (for a known oil, the upper limit is 50,000 cP, for the claimed one, in fact - 11,980 cP).

The disadvantages of the known hydraulic oil for automatic transmissions are high dynamic viscosity at subzero temperatures, which does not allow the use of hydraulic oil in the Far North, as well as an insufficient set of functional additives to ensure anti-corrosion properties.

Known hydraulic fluid for automatic transmissions on an oil or synthetic basis [2 - EU 0544298 A1]. As part of this fluid, detergents (phenates), antioxidants (dithiophosphates), anticorrosion agents, viscosity index modifiers and antifoam agents can be used as additives (additives) that improve functional properties. The essence of this invention is the use in the composition of the hydraulic fluid of a special additive - alkaline earth metal borate salt, which improves frictional properties.

A disadvantage of the known hydraulic fluid is an insufficient set of functional additives and the lack of information on the viscosity-temperature characteristics of the oil.

Known hydraulic fluid [3 - US 5,094,763], which has the following composition:

mineral or synthetic base;

additives (or additives):

- anti-corrosion (for example, thiadiazoline derivatives);

- antioxidant additive (phenol derivatives);

- viscosity index modifier (polymethacrylates);

- detergent additive (sulfonates);

- antifoam (siloxanes).

The essence of this invention is the replacement of zinc dithiophosphates, which are a component of a hydraulic fluid, with thiadiazoline derivatives. The authors of this invention declare that the new composition of the hydraulic fluid will provide long-term operation of hydraulic systems without compromising the durability of rubber materials. The disadvantage of this hydraulic fluid is the lack of information on such important and standard in the modern requirements for the quality of hydraulic fluids for automatic transmissions indicators, as dynamic viscosity at minus 40 ° C, as well as a tendency to foaming. In addition, the use of synthetic components in the composition of the liquid leads to a rise in price of the product.

The prior art functional fluid [4 - US 6,255,546] with improved Brookfield dynamic viscosity at minus 40 ° C, which can be used for automatic and hydraulic systems. The liquid contains a mixture of hydrocracking oils and selective cleaning, as well as a functional additive package, including a viscosity modifier, antiwear, anti-corrosion, anti-oxidative, anti-foam and other additives. A disadvantage of the known functional fluid is a lower viscosity index compared to the claimed hydraulic fluid for automatic transmissions. Known functional fluid has a viscosity index in the range of 150-200, and the claimed hydraulic fluid is above 200 (actually 204-218, Table 4).

Closest to the claimed hydraulic fluid for automatic transmissions, a fluid for automatic transmissions [5 - US 6,077,455]. In the present invention, an isomerized oil obtained by hydrotreating, hydro-isodeparaffinization, hydrogenation and fractionation is used as a component for automatic transmissions. The oil has a kinematic viscosity at 100 ° C above 3 cSt, Brookfield viscosity at minus 40 ° C about 15000 cP. The oil contains anticorrosive, antioxidant, dispersing, antifoam, antiwear and other additives. The specified invention is aimed at improving the viscosity-temperature characteristics.

A disadvantage of the known hydraulic fluid is the lack of information about such important indicators as the viscosity index and the tendency to foaming, which make it possible to more fully evaluate the performance characteristics of fluids for automatic transmissions.

The basis of the present invention is the creation of a new hydraulic fluid for automatic transmissions with improved viscosity-temperature characteristics, lower dynamic viscosity at sub-zero temperatures, less prone to foaming, which allows it to be used in a wide temperature range.

The goal is solved by the fact that in the composition of the hydraulic fluid for automatic transmissions containing additives: multifunctional (antiwear, antioxidant, friction modifier, viscosity modifier), anticorrosive, antifoam and dye, a mixture of mineral base oil - a low-viscosity distillate is used as the base component representing mineral oil obtained from the vacuum distillate of the primary oil refining units (fraction 300-450 ° C) by selection explicit purification, dewaxing and hydrotreating, and isomerized hatch (fraction 360 ° С - К.К.), obtained by catalytic method from oil hatch - a by-product of raffinate dewaxing plants (fraction 300 ° С - К.К.) with an oil content of from 2.5% wt. up to 12.0% wt. by hydrotreating, hydroisodeparaffinization, hydrogenation, followed by fractionation at a certain ratio. The ratio of the components of the inventive hydraulic fluid for automatic transmissions is shown in Table 1.

Due to the joint use of a mixture of two components as a basic basis: a low-viscosity distillate component and an isomerized pump, we manage to obtain a new result in the proposed hydraulic fluid: to reduce the dynamic viscosity at minus 40 ° C from 20,000 cP (typical specifications) to 11,980 cP, to ensure high viscosity index, reduce the tendency of the oil to foam.

This effect is due to the optimal ratio and the combined action of a mixture of a low-viscosity distillate component and an isomerized pump, which is confirmed by the test results of the proposed hydraulic fluid presented below.

In the selected ratio of components, the synergistic effect is maximum. The advantages of this composition are the possibility of its use in automatic transmissions of modern advanced manufacturers that put forward strict technical requirements for product quality (Table 4).

In the composition of the claimed fluid used:

- multifunctional additive (represents Infineum T 4560, including additives: antiwear, antioxidant, friction modifier, viscosity modifier, manufactured industrially under the Quality Certificate);

- anticorrosive additive (it is an Infineum C 9488 additive, manufactured industrially according to the Quality Certificate);

- antifoam (polymethylsiloxane, is an additive Infineum C 9496, manufactured industrially according to the Quality Certificate);

- dye (dye dark red fat-soluble "Zh" is produced according to TU 6-14-37-80 rev. 1, 2, 3).

The properties of the low-viscosity distillate component and the isomerized sac according to the alleged invention are shown in Table 2.

A method of obtaining the inventive hydraulic fluid for automatic transmissions is to mix a low-viscosity distillate component and an isomerized pump with additives at a temperature of 60-80 ° C. Thus, samples of 6 compositions were prepared, including samples No. 1 and No. 6, the ratio of components in which is outside the claimed quantitative ratios.

The ratio of the components in the samples of the claimed hydraulic fluid for automatic transmissions is shown in Table 3.

Example 1

Hydraulic fluid is prepared by mixing a low-viscosity distillate component and an isomerized pump according to the compositions of samples No. 2, 3, 4, 5 (see Table 3) and additives: multifunctional, anti-corrosion, anti-foam, dye. The calculated quantities of the low-viscosity distillate component (33570 kg) and isomerized gacha (18355 kg) are pumped into the tank. Additives are added in the form of a concentrate based on isomerized gach. Additive concentrate is prepared in a mixer. First, an isomerized gach is pumped into the mixer (the amount of base is 32,000 kg), then additives are dosed (multifunctional - 16,000 kg, anticorrosive - 70 kg and dark red dye - 2.5 kg), where they are mixed at a temperature of 60-80 ° С . Then, the calculated amount of antifoam additive - 3 kg with a portable dispenser is fed into the mixer. On the mixer, a stirring device is turned on, and after mixing, the concentrate is set for analysis according to the following indicators: kinematic viscosity at 100 ° C, water content, flash point in an open crucible, pour point. After obtaining positive results, the additive concentrate is filtered through a filter press (if necessary) and fed into the tank with a mixture of a low-viscosity distillate component and isomerized pump. In the tank, the base is mixed with additives. Hydraulic fluid is asked for a full analysis. Samples were tested according to the technical requirements for modern hydraulic fluids for automatic transmissions. The results are shown in table 4.

Table 4, for clarity, shows typical technical requirements for the quality of the claimed fluid for automatic transmissions, the test results of the inventive fluid (columns 3, 4, 5, 6, 7, 8). The table shows that with a decrease in the percentage of involvement of the isomerized pump as part of the base hydraulic fluid for automatic transmissions to 20%, the kinematic viscosity at 100 ° C does not meet the stated typical specifications when it increases to 85%. In sample No. 6, anti-foam properties are also deteriorating. In addition, from Table 4 it is seen that samples No. 2, 3, 4 and 5, prepared in accordance with the claimed ratio of the components, have improved low-temperature properties, in particular, the dynamic viscosity at minus 40 ° C is in the range of 11980-12660 cP, at typical technical requirements - no more than 20,000 cP.

An increase in the proportion of isomerized slag in the composition of the liquid has a positive effect on the index “viscosity index” (Sample No. 2, Table 4), which allows the use of liquid in a wider temperature range. The tendency of the hydraulic fluid to foam is also reduced. Thus, the claimed hydraulic fluid for automatic transmissions meets the typical technical requirements for modern automatic transmissions, has improved viscosity-temperature characteristics, lower dynamic viscosity at sub-zero temperatures, improved anti-foam properties and can be used in cars operating in the North at operating oil temperatures from minus 47 ° C to minus 56 ° C.

Table 1 The ratio of the components of the inventive hydraulic fluid for automatic transmissions Component The ratio of components, wt.% Multifunctional additive 14-18 Corrosion Prevention Agent 0.06-0.1 Antifoam additive 0.002-0.006 Dye 0.002-0.003 Basic foundation up to 100 moreover, the base framework contains: - low viscosity distillate component 20 ÷ 70 - isomerized gach 30 ÷ 80

table 2 Properties of low viscosity distillate component and isomerized hach according to the invention The name of indicators Low viscosity distillate component Isomerized Gach 1. Kinematic viscosity at 100 ° C, mm ² / s 2.5 ÷ 4.0 3.9 ÷ 4.7 2. Viscosity Index 94 140 3. The pour point, ° C, not higher minus 10 minus 15 4. Flash point on open. crucible, ° C, not lower 165 210

Table 3 The ratio of the components in the samples of the inventive hydraulic fluid for automatic transmissions The ratio of components, wt.% Component Arr. No. 1 Arr. Number 2 Arr. Number 3 Arr. Number 4 Arr. Number 5 Arr. Number 6 Multifunctional additive 16 16 16 16 16 16 Corrosion Prevention Agent 0,07 0,07 0,07 0,07 0,07 0,07 Antifoam additive 0.003 0.003 0.003 0.003 0.003 0.003 Dye 0.0025 0.0025 0.0025 0.0025 0.0025 0.0025 Basic foundation up to 100 up to 100 up to 100 up to 100 up to 100 up to 100 moreover, the base framework contains: - low viscosity distillate component fifteen twenty 40 60 70 80 - isomerized gach 85 80 60 40 thirty twenty

Claims (1)

A hydraulic fluid for automatic transmissions containing a base base and additives: multifunctional (antiwear, antioxidant, friction modifier, viscosity modifier), anticorrosive, antifoam additives and dye, characterized in that it contains a mixture of a low-viscosity distillate component, which is a base mineral oil obtained from the vacuum distillate of primary oil refining units (fraction 300-450 ° С) by selective purification, dewaxing and hydro purification, and isomerized gacha (fraction 360 ° С - К.К.), obtained catalytically from oil gacha - a by-product of raffinate dewaxing plants (fraction 300 ° С - К.К.) with an oil content of 2.5 to 12 wt. .% by hydrotreating, hydroisodeparaffinization, hydrogenation, followed by fractionation in the following ratio of components, wt.%:
multifunctional additive 14-18 anticorrosive additive 0.06-0.1 antifoam additive 0.002-0.006 dye 0.002-0.003 base foundation up to 100
moreover, the base framework contains:
- low viscosity distillate component 20-70 - isomerized gach 30-80