Power transmitting fluids with improved materials compatibility
A power transmitting fluid comprises a major amount of a lubricating oil and a minor amount of an additive composition. The additive composition comprises: (a) a friction modifier of the formula: (b) an oil-soluble phosphorus compound; and, (c) an ashless dispersant; wherein R 1 and R 2 may be the same or different and represent linear or branched, saturated or unsaturated hydrocarbyl groups having from 8 to 20 carbon atoms. Z represents a polyoxyalkylene segment or a polyalkoxylated alkyl amine segment. The friction modifiers provide the fluid with improved fluoroelastomer seal compatibility and enhanced copper corrosion compatibility.
1. A power transmitting fluid comprising a major amount of a natural lubricating oil and a minor amount of an additive composition, the additive composition comprising:
(a) a friction modifier of the formula:
(b) an oil-soluble phosphorus compound: and
(c) an ashless dispersant:
where R 1 and R 2 may be the same or different and represent linear or branched, saturated or unsaturated hydrocarbyl groups having from 8 to 20 carbon atoms;
wherein Q represents an alkylene group having 1 to 4 carbon atoms; and
wherein a is an integer from 5 to 15.
2. A fluid according to claim 1 wherein Q or each Q is an ethylene group.
3. A fluid according to claim 2 wherein R 9 is an alkyl group.
4. A fluid according to claim 1 wherein R 1 and R 2 are the same.
5. A fluid according to claim 1 wherein R 1 and R 2 are linear or branched, saturated or unsaturated alkyl groups having from 4 to 20 carbon atoms.
6. A fluid according to claim 1 wherein the fluid further comprises one or more corrosion inhibitors.
7. A fluid according to claim 1 wherein the fluid further comprises one or more metal-containing detergents.
8. A fluid according to claim 1 , which is an automatic transmission fluid.
9. A method of formulating a power transmitting fluid with improved fluoroelastomer seal compatibility, the method comprising combining a major amount of a natural lubricating oil with a minor amount of an additive composition as defined in claim 1 .
10. A method of formulating a power transmitting fluid with improved copper corrosion compatibility, the method comprising combining a major amount of a lubricating oil with a minor amount of an additive composition as defined in claim 1 .