Multigrade lubricating compositions

Abstract

The invention relates to a method of lubricating a mechanical device (such as an internal combustion engine) with a lubricating composition. The invention further relates to the use of the lubricating composition for an internal combustion engine to provide improved fuel economy and providing at least one of (i) wear reduction, (ii) control of corrosion, (iii) cleanliness, and (iv) soot control.

What is claimed is: 
     
         1 . A multigrade lubricant composition, comprising:
 (a) an oil of lubricating viscosity having a viscosity index of at least 110 or 120 to 140 or 150;   (b) an ashless dispersant; and   (c) an overbased metal detergent wherein the lubricating composition contains less than 0.01 weight percent of a polymeric viscosity index improver; wherein the lubricant composition has a SAE viscosity grade of XW-Y, wherein X may be 0, 5, or 10; and Y may be 16, 20, 26, 30, or 40.   
     
     
         2 . The lubricant composition of  claim 1 , wherein the multigrade crank-case lubricant is a SAE 0W-16, 0W-20, 0W-26, 5W-16, 5W-20, 5W-26, 5W-30, 10W-16, 10W-30, or 10W-40 lubricant. 
     
     
         3 . The lubricating composition of  claim 1 , wherein the ashless dispersant is derived from a polyolefin having a number average molecular weight of 500 to 000. 
     
     
         4 . The lubricating composition of  claim 1 , wherein the metal-containing overbased detergent comprises one or more of a calcium sulfonate, a calcium phenate, a magnesium sulfonate or a magnesium phenate. 
     
     
         5 . The lubricating composition of  claim 4 , where the metal-containing overbased detergent is present in amount to deliver at least 4 TBN to the composition. 
     
     
         6 . The lubricating composition of  claim 1 , wherein the lubricating composition has a viscosity index of at least 130 or at least 135. 
     
     
         7 . The lubricant of  claim 1 , wherein the oil of lubricating viscosity has a viscosity index of at least 124. 
     
     
         8 . The lubricant composition of  claim 1 , wherein the oil of lubricating viscosity comprises from 0.1 weight percent to 20 weight percent of an oil derived from hydroisomerization of a high wax-containing feed stream. 
     
     
         9 . The lubricant composition of  claim 1 , wherein the oil of lubricating viscosity comprises from 0.5 weight percent to 5 weight percent of an oil derived from hydroisomerization of a high wax-containing feed stream. 
     
     
         10 . A method of lubricating a compression-ignition internal combustion engine comprising supplying to said engine a lubricant composition according to  claim 1 . 
     
     
         11 . A method of improving the fuel economy of a compression-ignition internal combustion engine comprising supplying to the engine a SAE 0W-16, 0W-20, 0W-26, 5W-16, 5W-20, 5W-26, 5W-30, 10W-16, 10W-30, or 10W-40 lubricant, wherein the lubricant comprises:
 (a) an oil of lubricating viscosity having a viscosity index of at least 115;   (b) an ashless dispersant, and (c) an overbased metal detergent,   wherein the lubricating composition contains less than 0.01 weight percent of a polymeric viscosity modifier.   
     
     
         12 . A multigrade crankcase lubricant composition having a viscosity index of at least 130, comprising:
 (a) an oil of lubricating viscosity having a viscosity index of at least 115;   (b) an ashless dispersant; and   (c) an overbased metal detergent,   wherein the lubricating composition contains less than 0.1 weight percent of an ethylene-olefin-based copolymer.   
     
     
         13 . The lubricant composition of  claim 12 , wherein in the ethylene-olefin-based copolymer, ethylene makes up from 50 percent to 90 percent of the monomer used to prepare the copolymer on a molar basis. 
     
     
         14 . The lubricant composition of  claim 13 , wherein the ethylene-olefin copolymer has a molecular weight from 5,000 to 40,000 Mn. 
     
     
         15 . The lubricant composition of  claim 12 , wherein no more than 50% of the overbased metal detergent contains a salicylate soap.