Method for improving engine fuel efficiency

Abstract

A method for improving fuel efficiency, while maintaining or improving high temperature wear, deposit and varnish control, in an engine lubricated with a lubricating oil by using as the lubricating oil a formulated oil. The formulated oil has a composition including a lubricating oil base stock as a major component, and at least one alkoxylated alcohol as a minor component. Fuel efficiency is improved and high temperature wear, deposit and varnish control are maintained or improved as compared to high temperature wear, deposit and varnish control achieved using a lubricating engine oil containing a minor component other than the at least one alkoxylated alcohol. A lubricating engine oil having a composition including a lubricating oil base stock as a major component, and at least one alkoxylated alcohol as a minor component. The lubricating engine oils are useful in internal combustion engines including direct injection, gasoline and diesel engines.

What is claimed is: 
     
         1 . A method for improving fuel efficiency, while maintaining or improving high temperature wear, deposit and varnish control, in an engine lubricated with a lubricating oil by using as the lubricating oil a formulated oil, said formulated oil having a composition comprising a lubricating oil base stock as a major component; and at least one alkoxylated alcohol, as a minor component; wherein fuel efficiency is improved and high temperature wear, deposit and varnish control are maintained or improved as compared to high temperature wear, deposit and varnish control achieved using a lubricating engine oil containing a minor component other than the at least one alkoxylated alcohol. 
     
     
         2 . The method of  claim 1  wherein the lubricating oil base stock comprises a Group I, Group II, Group III, Group IV or Group V base oil. 
     
     
         3 . The method of  claim 1  wherein, in comparison with fuel efficiency achieved using a lubricating engine oil containing a minor component other than the at least one alkoxylated alcohol, the lubricating engine oil containing at least one alkoxylated alcohol exhibits a fuel efficiency, FEI sum, greater than 1.2×, as determined by a Sequence VID Fuel Economy (ASTM D7589) engine test; and wherein, in comparison with high temperature wear, deposit and varnish control achieved using a lubricating engine oil containing a minor component other than the at least one alkoxylated alcohol, the lubricating engine oil containing at least one alkoxylated alcohol exhibits high temperature wear, deposit and varnish control greater than 1.1×, as determined by a Sequence IIIG/IIIGA (ASTM D7320) engine test. 
     
     
         4 . The method of  claim 1  wherein the alkoxylated alcohol is represented by the formula
   R 1 —[O—(CH 2 ) x ] y —OH
 
 
       wherein R 1  is a hydrocarbon group having from 1 to 50 carbon atoms, x is an integer from 1 to 10, and y is an integer from 1 to 10. 
     
     
         5 . The method of  claim 4  wherein the alkoxylated alcohol is selected from stearyl alcohol ethoxylate, lauryl alcohol ethoxylate, oleyl alcohol ethoxylate, stearyl alcohol propoxylate, lauryl alcohol propoxylate, oleyl alcohol propoxylate, stearyl alcohol butoxylate, octyl alcohol butoxylate, myristyl alcohol ethoxypropoxylate, stearyl alcohol ethoxypropoxylate, lauryl alcohol ethoxypropoxylate, and mixtures thereof. 
     
     
         6 . The method of  claim 1  wherein the alkoxylated alcohol is represented by the formula
   R 2 O—(R 3 —O—) z H
 
 
       wherein R 2  is a branched or linear hydrocarbon group having from 12 to 20 carbon atoms, R 3  is an alkylene group having from 2 to 4 carbon atoms, and z is an integer from 1 to 10. 
     
     
         7 . The method of  claim 6  wherein the alkoxylated alcohol is selected from polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxypropylene stearyl ether, polyoxypropylene lauryl ether, polyoxypropylene oleyl ether, polyoxybutylene stearyl ether, polyoxybutylene octyl ether, poly(oxyethylene)(oxypropylene) myristyl ether, poly(oxyethylene)(oxypropylene) stearyl ether, poly(oxyethylene)(oxypropylene) lauryl ether, and mixtures thereof. 
     
     
         8 . The method of  claim 1  wherein the oil base stock is present in an amount of from 70 weight percent to 95 weight percent, and the at least one alkoxylated alcohol is present in an amount of from 0.05 weight percent to 6 weight percent, based on the total weight of the formulated oil. 
     
     
         9 . The method of  claim 1  wherein, in friction measurements of the lubricating oil by mini-traction machine (MTM) in Striheck mode at 50° C. and 100° C., the integrated Stribeck friction coefficient of the lubricating oil in the MTM is reduced as compared to the integrated Stribeck friction coefficient of a lubricating oil containing a minor component other than the at least one alkoxylated alcohol. 
     
     
         10 . The method of  claim 1  wherein phosphorus retention is improved as compared to phosphorus retention achieved using a lubricating engine oil containing a minor component other than the at least one alkoxylated alcohol. 
     
     
         11 . A lubricating engine oil having a composition comprising a lubricating oil base stock as a major component; and at least one alkoxylated alcohol, as a minor component; wherein fuel efficiency is improved and high temperature wear, deposit and varnish control are maintained or improved as compared to high temperature wear, deposit and varnish control achieved using a lubricating engine oil containing a minor component other than the at least one alkoxylated alcohol. 
     
     
         12 . The lubricating engine oil of  claim 11  wherein the lubricating oil base stock comprises a Group I, Group II, Group III, Group IV or Group V base oil. 
     
     
         13 . The lubricating engine oil of  claim 11  wherein, in comparison with fuel efficiency achieved using a lubricating engine oil containing a minor component other than the at least one alkoxylated alcohol, the lubricating engine oil containing at least one alkoxylated alcohol exhibits a fuel efficiency, FEI sum, greater than 1.2×, as determined by a Sequence YID Fuel Economy (ASTM D7589) engine test; and wherein, in comparison with high temperature wear, deposit and varnish control achieved using a lubricating engine oil containing a minor component other than the at least one alkoxylated alcohol, the lubricating engine oil containing at least one alkoxylated alcohol exhibits high temperature wear, deposit and varnish control greater than 1.1×, as determined by a Sequence IIIG/IIIGA (ASTM D7320) engine test. 
     
     
         14 . The lubricating engine oil of  claim 11  wherein the alkoxylated alcohol is represented by the formula
   R 1 —[O—(CH 2 ) x ] y —OH
 
 
       wherein R 1  is a hydrocarbon group having from 1 to 50 carbon atoms, x is an integer from 1 to 10, and y is an integer from 1 to 10. 
     
     
         15 . The lubricating engine oil of  claim 14  wherein the alkoxylated alcohol is selected from stearyl alcohol ethoxylate, lauryl alcohol ethoxylate, oleyl alcohol ethoxylate, stearyl alcohol propoxylate, lauryl alcohol propoxylate, oleyl alcohol propoxylate, stearyl alcohol butoxylate, octyl alcohol butoxylate, myristyl alcohol ethoxypropoxylate, stearyl alcohol ethoxypropoxylate, and lauryl alcohol ethoxypropoxylate. 
     
     
         16 . The lubricating engine oil of  claim 11  wherein the alkoxylated alcohol is represented by the formula
   R 2 O—(R 3 —O—) z H
 
 
       wherein R 2  is a hydrocarbon group having from 12 to 20 carbon atoms, R 3  is an alkylene group having from 2 to 4 carbon atoms, and z is an integer from 1 to 10. 
     
     
         17 . The lubricating engine oil of  claim 16  wherein the alkoxylated alcohol is selected from polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxypropylene stearyl ether, polyoxypropylene lauryl ether, polyoxypropylene oleyl ether, polyoxybutylene stearyl ether, polyoxybutylene octyl ether, poly(oxyethylene)(oxypropylene) myristyl ether, poly(oxyethylene)(oxypropylene) stearyl ether, and poly(oxyethylene)(oxypropylene) lauryl ether. 
     
     
         18 . The lubricating engine oil of  claim 11  wherein the oil base stock is present in an amount of from 70 weight percent to 95 weight percent, and the at least one alkoxylated alcohol is present in an amount of from 0.05 weight percent to 6 weight percent, based on the total weight of the formulated oil. 
     
     
         19 . The lubricating engine oil of  claim 11  wherein the lubricating oil further comprises one or more of an anti-wear additive, viscosity index improver, antioxidant, detergent, dispersant, pour point depressant, corrosion inhibitor, metal deactivator, seal compatibility additive, anti-foam agent, inhibitor, and anti-rust additive. 
     
     
         20 . The lubricating engine oil of  claim 11  wherein the lubricating oil is a passenger vehicle engine oil (PVEO).