Polyol Ester Based Drive-Train Fluid for High Stress Automatic Transmissions
AssigneeChemtura Corporation
InventorsSalvatore Rea, David Cooper, Robert Vinson
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Abstract
The use of certain polyol ester (POE) based fluids has been found to be surprisingly effective in, e.g., automotive automatic transmissions, such as, for example, racing automotive automatic transmissions. The use of select POE based fluids has been found to lower operating temperatures, improve torque convertor engagement and torque convertor lock-up due to improved efficiency, performance and friction properties, allowing improved efficiency in high stress applications.
Claims20
A mechanical device comprising a fluid coupling and a hydraulic transfer fluid, said hydraulic transfer fluid being a working fluid comprising:
- i) from 80 to 99% by weight of a polyol ester composition comprising C5-10 alkylcarboxlate esters of pentaerythritol, di-pentaerythritol, tri-pentaerythritol and/or higher pentaerythritol oligomers;
- and
- ii) from 1 to 20% by weight of additives selected from dispersants;
- anti-wear agents;
- anti-oxidants;
- corrosion inhibitors;
- friction modifiers;
- seal swell agents;
- anti-foamants viscosity modifiers, detergents, pour point depressants;
- wherein the working fluid has a kinematic viscosity at 40° C. of from 4 to 64 cSt, a kinematic viscosity at 100° C. of from 2 to 28 cSt, and a viscosity index of greater than greater than 100.
An improved method for operating an automatic transmission comprising a fluid coupling and a hydraulic transfer fluid, the improvement being selecting as the hydraulic transfer fluid a working fluid comprising:
- i) from 80 to 99% by weight of a polyol ester composition comprising C5-10 alkylcarboxlate esters of pentaerythritol, di-pentaerythritol, tri-pentaerythritol and/or higher pentaerythritol oligomers;
- and
- ii) from 1 to 20% by weight of additives selected from dispersants;
- anti-wear agents;
- anti-oxidants;
- corrosion inhibitors;
- friction modifiers;
- seal swell agents;
- anti-foamants viscosity modifiers, detergents, pour point depressants;
- wherein the working fluid has a kinematic viscosity at 40° C. of from 4 to 64 cSt, a kinematic viscosity at 100° C. of from 2 to 28 cSt, and a viscosity index of greater than greater than 100.
Dependencies are inferred from the claim text.