High efficiency engine oil compositions

Abstract

The present application pertains to a lubricating oil composition for an internal combustion engine that advantageously which exhibits improved fuel economy. The composition may comprise a major amount of oil of lubricating viscosity, an alkaline earth metal sulfonate detergent, and a comb-shaped polymethacrylate viscosity modifier. The compositions may be an 0W-8, an 0W-12, an 0W-16, or an 0W-20 SAE viscosity grade and be particularly useful for a hybrid vehicle.

1 . A lubricating oil composition for an internal combustion engine, comprising:
 a) a major amount of oil of lubricating viscosity;   b) an alkaline earth metal sulfonate detergent providing 1200-2200 ppm of metal to the lubricating oil composition;   c) a comb-shaped polymethacrylate viscosity modifier having a PSSI of less than 15;   wherein the lubricating oil composition is an 0W-8, an 0W-12, an 0W-16, or an 0W-20 SAE viscosity grade; and   wherein the lubricating oil composition is substantially free of a friction modifier.   
     
     
         2 . The lubricating oil composition of  claim 1  wherein the lubricating oil composition has a viscosity index of greater than 200. 
     
     
         3 . The lubricating oil composition of  claim 1  wherein the composition comprises less than 50 ppm of a friction modifier. 
     
     
         4 . The lubricating oil composition of  claim 1  wherein the composition comprises less than 25 ppm of a friction modifier. 
     
     
         5 . The lubricating oil composition of  claim 1  wherein the composition comprises 0 ppm of a friction modifier. 
     
     
         6 . The lubricating oil composition of  claim 1  wherein the composition exhibits a fuel economy improvement (FEI) of at least about 1%. 
     
     
         7 . The lubricating oil composition of  claim 1  wherein the composition exhibits a fuel economy improvement (FEI) of at least about 2%. 
     
     
         8 . The lubricating oil composition of  claim 1  wherein the lubricating oil composition is an 0W-8 SAE viscosity grade. 
     
     
         9 . The lubricating oil composition of  claim 1  wherein the lubricating oil composition is an 0W-12 SAE viscosity grade. 
     
     
         10 . The lubricating oil composition of  claim 1  wherein the lubricating oil composition is an 0W-16 SAE viscosity grade. 
     
     
         11 . The lubricating oil composition of  claim 1  wherein the lubricating oil composition is an 0W-20 SAE viscosity grade. 
     
     
         12 . The lubricating oil composition of  claim 1  wherein the alkaline earth metal sulfonate detergent is a magnesium sulfonate detergent, a calcium sulfonate detergent, or a mixture thereof. 
     
     
         13 . A method for improving fuel economy in an internal combustion engine comprising lubricating said engine with a lubricating oil composition comprising:
 a) a major amount of oil of lubricating viscosity;   b) an alkaline earth metal sulfonate detergent providing 1200-2200 ppm of metal to the lubricating oil composition;   c) a comb-shaped polymethacrylate viscosity modifier having a PSSI of less than 15;   wherein the lubricating oil composition is an 0W-8, an 0W-12, an 0W-16, or an 0W-20 SAE viscosity grade; and   wherein the lubricating oil composition is substantially free of a friction modifier.   
     
     
         14 . The method of  claim 13  wherein the lubricating oil composition has a viscosity index of greater than 200. 
     
     
         15 . The method of  claim 13  wherein the composition comprises less than 50 ppm of a friction modifier. 
     
     
         16 . The method of  claim 13  wherein the composition comprises less than 25 ppm of friction modifier. 
     
     
         17 . The method of  claim 13  wherein the composition comprises 0 ppm of a friction modifier. 
     
     
         18 . The method of  claim 13  wherein the composition exhibits a fuel economy improvement (FEI) of at least about 1%. 
     
     
         19 . The method of  claim 13  wherein the composition exhibits a fuel economy improvement (FEI) of at least about 2%. 
     
     
         20 . The method of  claim 13  wherein the lubricating oil composition is an 0W-8 SAE viscosity grade. 
     
     
         21 . The method of  claim 13  wherein the lubricating oil composition is an 0W-12 SAE viscosity grade. 
     
     
         22 . The method of  claim 13  wherein the lubricating oil composition is an 0W-16 SAE viscosity grade. 
     
     
         23 . The method of  claim 13  wherein the lubricating oil composition is an 0W-20 SAE viscosity grade. 
     
     
         24 . The method of  claim 13  wherein the alkaline earth metal sulfonate detergent is a magnesium sulfonate detergent, a calcium sulfonate detergent, or a mixture thereof.