Fuel economy engine oil composition

Abstract

The present invention is directed to a lubricating oil additive containing a vicinal diol and a particular detergent blend typically is low viscosity base oils whereby exhibiting improved fuel economy. In this respect, disclosed is a lubricating oil composition comprising: a major amount of base oil of lubricating viscosity; a friction modifier which is selected from the group consisting of C 10 -C 30 alkane 1,2-diols and C 10 -C 30 alkene 1,2-diols; an overbased alkyl alkaline earth metal hydroxybenzoate detergent having a metal ratio less than 3.0; and an overbased alkyl calcium sulfonate or an overbased alkyl calcium hydroxybenzoate having a metal ratio of 3.5 or greater.

What is claimed is: 
     
         1 . A lubricating oil composition comprising:
 a. a major amount of base oil of lubricating viscosity;   b. a friction modifier which is selected from the group consisting of C 10 -C 30  alkane 1,2-diols and C 10 -C 30  alkene 1,2-diols;   c. an overbased alkyl alkaline earth metal hydroxybenzoate detergent having a metal ratio less than 3.0; and   d. an overbased alkyl calcium sulfonate or an overbased alkyl calcium hydroxybenzoate having a metal ratio of 3.5 or greater.   
     
     
         2 . The lubricating oil composition according to  claim 1 , wherein the friction modifier is selected from the formula R 1 —CH(OH)CH 2 (OH) wherein R 1  is alkyl containing from 8 to 28. 
     
     
         3 . The lubricating oil composition according to  claim 2 , wherein the friction modifier is a C 10 -C 30  alkane 1,2-diol derived from a linear alkyl containing from 14 to 18 carbon atoms. 
     
     
         4 . The lubricating oil composition according to  claim 3 , wherein the friction modifier is in amount from 0.02 to 5.0 wt. % based upon the total weight of the lubricating oil composition. 
     
     
         5 . The lubricating oil composition according to  claim 1 , wherein the overbased alkyl alkaline earth metal hydroxybenzoate detergent having a metal ratio less than 3.0 has an alkyl chain length of 14 to 18 carbon atoms. 
     
     
         6 . The lubricating oil composition according to  claim 1 , wherein the overbased alkyl calcium sulfonate or an overbased alkyl calcium hydroxybenzoate having a metal ratio of 3.5 or greater has an alkyl chain length of 20 to 28 carbon atoms. 
     
     
         7 . The lubricating oil composition according to  claim 1 , wherein the overbased alkyl calcium sulfonate is selected having a metal ratio of 3.5 or greater has an alkyl chain length of 20 to 28 carbon atoms. 
     
     
         8 . The lubricating oil composition according to  claim 1 , wherein the overbased alkyl calcium hydroxybenzoate is selected having a metal ratio of 3.5 or greater has an alkyl chain length of 20 to 28 carbon atoms. 
     
     
         9 . The lubricating oil composition according to  claim 1 , wherein the base oil of lubricating viscosity has a viscosity index of greater than 110. 
     
     
         10 . The lubricating oil composition according to  claim 9 , wherein the base oil of lubricating oil has a HTHS viscosity of less than 2.9 mP·s at 150° C. as determined by ASTM D4683. 
     
     
         11 . The lubricating oil composition according to  claim 10 , wherein the lubricating oil composition is formulated to meet SAE viscosity grade 0W20. 
     
     
         12 . The lubricating oil composition according to  claim 9 , wherein the lubricating oil composition has a HTHS viscosity of less than 2.6 mP·s at 150° C. as determined by ASTM D4683. 
     
     
         13 . The lubricating oil composition according to  claim 9 , wherein the lubricating oil composition has a HTHS viscosity of less than 2.3 mP·s at 150° C. as determined by ASTM D4683. 
     
     
         14 . The lubricating oil composition according to  claim 13 , wherein the lubricating oil composition contains less than 3 wt % of viscosity index improver component. 
     
     
         15 . A lubricating oil composition for internal combustion engines comprising:
 a. a major amount of base oil of lubricating viscosity;   b. a C 10 -C 30  hydrocarbyl 1,2-diol in an amount from about 0.1 to 3 mass %;   c. an overbased alkyl (C 14 -C 18 ) alkaline earth metal hydroxybenzoate detergent having a metal ratio less than 3.0 in an amount from about 0.01 to 0.4 mass % based on alkaline earth metal content;   d. an overbased alkyl (C 20 -C 28 ) calcium sulfonate or an overbased alkyl (C 20 -C 28 ) calcium hydroxybenzoate having a metal ratio of 3.5 or greater in an amount from 0.01 to 0.4 mass % based on calcium content;   e. a nitrogen containing dispersant in terms of nitrogen content from about 0.01 to 0.3 mass %;   f. a zinc dialkydithiophosphate in the amount from 0.01 to 0.1% in terms of phosphorous content;   g. an oxidation inhibitor selected from the group consisting of a phenolic antioxidant or a diphenyl amine type antioxidant in the amount from 0.1 to 7 mass %; and   
       wherein the mass % is based upon the total amount of the lubricating oil composition.