Lubricating oil compositions

Abstract

The present application pertains to functional fluids or EV fluids. The functional fluids may comprise a major amount of an oil of lubricating viscosity, at least one overbased sulfonate detergent. and an anti-fatigue additive. The functional fluids or EV fluids provide surprising and unexpected fatigue properties.

1 . A functional fluid or EV fluid comprising:
 (a) a major amount of an oil of lubricating viscosity;   (b) an anti-fatigue additive comprising alkyl polyol having 2 to 20 carbon atoms; and   (c) at least one overbased sulfonate detergent;   wherein the amount of anti-fatigue additive is from about 0.001 wt. % to about 1.5 wt. % based on the total weight of the functional fluid or EV fluid.   
     
     
         2 . The functional fluid or EV fluid of  claim 1 , wherein the at least one overbased sulfonate detergent is a high overbased calcium sulfonate. 
     
     
         3 . The functional fluid or EV fluid of  claim 1 , further comprising a sulfurized calcium phenate detergent present in an amount to provide about 40 mmol or less of calcium. 
     
     
         4 . The functional fluid or EV Fluid of  claim 1 , wherein the functional fluid further comprises at least one dispersant additive. 
     
     
         5 . The functional fluid or EV Fluid of  claim 4 , wherein the at least one dispersant additive is an ethylene carbonate post treated bissuccinimide. 
     
     
         6 . The functional fluid or EV fluid of  claim 1 , further comprising at least one anti-wear additive. 
     
     
         7 . The functional fluid or EV fluid of  claim 6 , wherein the at least one anti-wear additive is a zinc dialkyl dithiophosphate. 
     
     
         8 . The functional fluid or EV fluid of  claim 7 , wherein the zinc dialkyl dithiophosphate is derived from a primary alcohol. 
     
     
         9 . The functional fluid or EV fluid of  claim 1 , wherein the anti-fatigue additive is glycerol, triglycerol, 1,2,4-butanetriol, 2,2-diethyl-1,3-propanediol, diglycerol, 3-methoxy-1,2-propanediol, myo-inositol, meso-erythritol, D-sorbitol, xylitol, D-(+)-xylose, D-(+)-glucose, pentaerythritol, dipentaerythritol; tripentaerythritol, ethylene glycol, diethylene glycol, triethylene glycol, 2,2-dimethyl-1,3-propanediol, or polyvinyl alcohol. 
     
     
         10 . The functional fluid or EV fluid of  claim 1 , wherein the functional fluid or EV fluid includes 3 wt. % or less of zinc dithiophosphate based on total weight of the functional fluid or EV fluid. 
     
     
         11 . A method of increasing the fatigue time of a bearing comprising contacting a metal surface with a functional fluid or EV fluid comprising:
 a) a major amount of an oil of lubricating viscosity;   (b) an anti-fatigue additive comprising alkyl polyol having 2 to 20carbon atoms; and   (c) at least one overbased sulfonate detergent; wherein the amount of anti-fatigue additive is from about 0.001 wt. % to about 1.5 wt. %.   
     
     
         12 . The method of  claim 11 , wherein the at least one overbased sulfonate detergent is a high overbased calcium sulfonate. 
     
     
         13 . The method of  claim 11 , wherein the functional fluid or EV fluid further comprises a sulfurized calcium phenate detergent present in an amount to provide about 40 mmol or less of calcium. 
     
     
         14 . The method of  claim 11 , wherein the functional fluid or EV fluid further comprises at least one dispersant additive. 
     
     
         15 . The method of  claim 11 , wherein the anti-fatigue additive is glycerol, triglycerol, 1,2,4-butanetriol, 1,1,1,-tris(hydroxymethyl)propane, 2,2-diethyl-1,3-propanediol, diglycerol, 3-methoxy-1,2,-propanediol, myo-inositol, meso-erythritol, D-sorbitol, xylitol, D-(+)-xylose, D-(+)-glucose, pentaerythritol, dipentaerythritol; tripentaerythritol, ethylene glycol, diethylene glycol, triethylene glycol, 2,2-dimethyl-1,3-propanediol, or polyvinyl alcohol. 
     
     
         16 . The method of  claim 11 , wherein the functional fluid or EV fluid includes less than 3 wt. % of zinc dithiophosphate based on the total weight of the functional fluid or EV fluid. 
     
     
         17 . A lubricating oil composition for hybrid vehicle or plug-in hybrid vehicles comprising:
 (a) a major amount of an oil of lubricating viscosity;   (b) an anti-fatigue additive comprising alkyl polyol having 2 to 20 carbon atoms; and   (c) at least one overbased sulfonate detergent;   wherein the amount of anti-fatigue additive is from about 0.001 wt. % to about 1.5 wt. % based on the total weight of the lubricating oil composition.   
     
     
         18 . The lubricating oil composition of  claim 17 , wherein the at least one overbased sulfonate detergent is a high overbased calcium sulfonate. 
     
     
         19 . The lubricating oil composition of  claim 17 , wherein the lubricating oil composition includes 3 wt. % or less of zinc dithiophosphate based on total weight of the lubricating oil composition. 
     
     
         20 . The lubricating oil composition of  claim 17 , wherein the lubricating oil composition includes calcium phenate detergent in an amount to provide about 40 mmol or less of calcium.