Lubricating oils for wet clutch systems

Abstract

The present invention generally relates to lubricating oil compositions useful for vehicles such as industrial machinery, especially transport, construction, and agricultural machinery. Also disclosed is a method for maintaining friction in said vehicles comprising lubricating said vehicles with said lubricating oil compositions.

1 . An industrial machinery lubricating oil composition comprising:
 (a) a major amount of oil of lubricating viscosity;   (b) at least 1000 ppm of calcium from a calcium containing detergent;   (c) at least 800 ppm of Mg from a magnesium containing detergent;   (d) less than 600 ppm of N from a nitrogen containing dispersant;   wherein the lubricating oil composition has a phosphorus content of from 0.06 to 0.15 wt. %, a sulfur content of less than 0.5 wt. % and a sulfated ash content of from greater than 0.8 wt. % to 2.0 wt. %,   wherein the mass ratio of Ca to Mg is from 1:2 to 4:1, and   wherein said lubricating oil composition lubricates the crankcase of an internal combustion engine of an industrial machinery and at least one of a wet clutch, brakes, torque converters, gear systems, hydro static transmissions and hydraulic systems.   
     
     
         2 . The lubricating oil composition of  claim 1 , wherein the calcium containing detergent provides at least 1000 ppm to not greater than 4000 ppm by weight of calcium to the lubricating oil composition. 
     
     
         3 . The lubricating oil composition of  claim 1 , wherein the total base number (TBN) of the lubricating oil composition is from 8 to 16 mg KOH/g. 
     
     
         4 . The lubricating oil composition of  claim 1 , wherein the sulfated ash is from about 0.80 to about 1.60 wt. % as determined by ASTM D 874. 
     
     
         5 . (canceled) 
     
     
         6 . The lubricating oil composition of  claim 1 , wherein the industrial machinery is a transport, a construction or an agricultural machinery 
     
     
         7 . The lubricating oil composition of  claim 1 , wherein the industrial machinery is equipped with an automatic transmission, or a continuously variable transmission. 
     
     
         8 . A method for maintaining friction in a vehicle comprising lubricating said vehicle with a lubricating oil composition comprising:
 (a) a major amount of oil of lubricating viscosity;   (b) at least 1000 ppm of calcium from a calcium containing detergent;   (c) at least 800 ppm of Mg from a magnesium containing detergent;   (d) less than 600 ppm of N from a nitrogen containing dispersant;   wherein the lubricating oil composition has a phosphorus content of from 0.06 to 0.15 wt. %, a sulfur content of less than 0.5 wt. % and a sulfated ash content of from greater than 0.8 wt. % to 2.0 wt. %,   wherein the mass ratio of Ca to Mg is from 1:2 to 4:1, and   wherein said lubricating oil composition lubricates the crankcase of an internal combustion engine of said vehicle and at least one of a wet clutch, brakes, torque converters, gear systems, hydro static transmissions and hydraulic systems.   
     
     
         9 . The method of  claim 8 , wherein the calcium containing detergent provides at least 1000 ppm to not greater than 4000 ppm by weight of calcium to the lubricating oil composition. 
     
     
         10 . The method of  claim 8 , wherein the vehicle is an industrial machinery, an automobile, a truck, or other vehicle. 
     
     
         11 . The method of  claim 10 , wherein the industrial machinery is a transport, a construction, or an agricultural machinery. 
     
     
         12 . The method of  claim 8 , wherein the vehicle is equipped with an automatic transmission, or a continuously variable transmission. 
     
     
         13 . The lubricating oil composition of  claim 1 , wherein the calcium containing detergent comprises a calcium sulfonate having a total base number (TBN) of about 30 to about 100 and the magnesium containing detergent comprises a highly overbased magnesium sulfonate detergent having a TBN of 250 to 450. 
     
     
         14 . The lubricating oil composition of  claim 1 , wherein the magnesium containing detergent provides at least 800 ppm to not greater than 4000 ppm by weight of magnesium to the lubricating oil composition. 
     
     
         15 . The lubricating oil composition of  claim 1 , wherein the nitrogen containing dispersant comprises one or more post treated dispersants. 
     
     
         16 . The method of  claim 8 , wherein the calcium containing detergent comprises a calcium sulfonate having a TBN of about 30 to about 100 and the magnesium containing detergent comprises a highly overbased magnesium sulfonate detergent having a TBN of 250 to 450. 
     
     
         17 . The method of  claim 8 , wherein the nitrogen containing dispersant comprises one or more post treated dispersants. 
     
     
         18 . The method of  claim 8 , wherein said vehicle is an industrial machinery equipped with a wet-clutch system. 
     
     
         19 . The method of  claim 8 , wherein said vehicle is a motorcycle equipped with a transmission and wet clutch. 
     
     
         20 . A motorcycle lubricating oil composition comprising:
 (a) a major amount of oil of lubricating viscosity;   (b) at least 1000 ppm of calcium from a calcium containing detergent;   (c) at least 800 ppm of Mg from a magnesium containing detergent;   (d) less than 600 ppm of N from a nitrogen containing dispersant;   wherein the lubricating oil composition has a phosphorus content of from 0.06 to 0.15 wt. %, a sulfur content of less than 0.5 wt. % and a sulfated ash content of from greater than 0.8 wt. % to 2.0 wt. %,   wherein the mass ratio of Ca to Mg is from 1:2 to 4:1, and   wherein said motorcycle lubricating oil composition lubricates the crankcase of an internal combustion engine of a motorcycle and at least one of a wet clutch and transmission.   
     
     
         21 . The motorcycle lubricating oil composition of  claim 21 , wherein the calcium containing detergent comprises a calcium sulfonate having a total base number (TBN) of about 30 to about 100, the magnesium containing detergent comprises a highly overbased magnesium sulfonate detergent having a TBN of 250 to 450 and the nitrogen containing dispersant comprises one or more post treated dispersants.