Lubricating oil composition

Abstract

A lubricating oil composition, particularly useful for use in gasoline engines, which has superior low fuel consumption properties is provided. A lubricating oil composition contains one or more salicylate-type detergents, one or more ashless friction modifiers and a base oil containing a base oil component having an oil film thickness of 95 nm or less, when measured under conditions of a sliding speed of 4.4 m/s, a Hertz pressure of 0.53 GPa and an oil temperature of 100° C.

1 . A lubricating oil composition comprising at least one salicylate-type detergent, at least one ashless friction modifier and a base oil, wherein the base oil comprises a base oil component having an oil film thickness of 95 nm or less, when measured under conditions of a sliding speed of 4.4 m/s, a Hertz pressure of 0.53 GPa and an oil temperature of 100° C.  
   
   
       2 . The lubricating oil composition of  claim 1  wherein the base oil component is present in an amount of 5% or more by mass, of the entire base oil.  
   
   
       3 . The lubricating oil composition of  claim 1  wherein the salicylate-type detergent is present in an amount in the range of from 0.5 to 10.0% by mass, based on the total mass of the lubricating oil composition.  
   
   
       4 . The lubricating oil composition of  claim 1  wherein the ashless friction modifier is present in an amount in the range of from 0.01 to 5.0% by mass, based on the total mass of the lubricating oil composition.  
   
   
       5 . The lubricating oil composition of  claim 1  wherein the salicylate-type detergent is selected from calcium and magnesium salicylate-type detergents.  
   
   
       6 . The lubricating oil composition of  claim 1  wherein the ashless friction modifier is a compound containing an oleyl group.  
   
   
       7 . The lubricating oil composition of  claim 1  wherein the base oil component has an oil film thickness of 80 nm or less, when measured under conditions of a sliding speed of 4.4 m/s, a Hertz pressure of 0.53 GPa and an oil temperature of 100° C.  
   
   
       8 . The lubricating oil composition of  claim 2  wherein the salicylate-type detergent is present in an amount in the range of from 0.5 to 10.0% by mass, based on the total mass of the lubricating oil composition.  
   
   
       9 . The lubricating oil composition of  claim 8  wherein the ashless friction modifier is present in an amount in the range of from 0.01 to 5.0% by mass, based on the total mass of the lubricating oil composition.  
   
   
       10 . The lubricating oil composition of  claim 5  wherein the ashless friction modifier is a compound containing an oleyl group.  
   
   
       11 . The lubricating oil composition of  claim 2  wherein the salicylate-type detergent is selected from calcium and magnesium salicylate-type detergents.  
   
   
       12 . The lubricating oil composition of  claim 11  wherein the ashless friction modifier is a compound containing an oleyl group.  
   
   
       13 . The lubricating oil composition of  claim 9  wherein the salicylate-type detergent is selected from calcium and magnesium salicylate-type detergents.  
   
   
       14 . The lubricating oil composition of  claim 13  wherein the ashless friction modifier is a compound containing an oleyl group.  
   
   
       15 . The lubricating oil composition of  claim 14  wherein the base oil component has an oil film thickness of 80 nm or less, when measured under conditions of a sliding speed of 4.4 m/s, a Hertz pressure of 0.53 GPa and an oil temperature of 100° C.  
   
   
       16 . A lubricating composition comprising: 
 (a) a base oil comprising 5% or more by mass, based on the entire base oil, of a base oil component having an oil film thickness of 80 nm or less, when measured under conditions of a sliding speed of 4.4 m/s, a Hertz pressure of 0.53 GPa and an oil temperature of 100° C.    (b) from 0.5 to 10.0% by mass, based on the total mass of the lubricating oil composition, of a salicylate-type detergent; and    (c) from 0.01 to 5% by mass, based on the total mass of the lubricating oil composition, of an ashless friction modifier that contains an oleyl group.    
   
   
       17 . A method of reducing fuel consumption in an internal combustion engine comprising lubricating said internal combustion engine with a lubricating oil composition of  claim 1 .  
   
   
       18 . A method of reducing fuel consumption in an internal combustion engine comprising lubricating said internal combustion engine with a lubricating oil composition of  claim 16 .  
   
   
       19 . A method of lubricating an internal combustion engine comprising applying to said engine a lubricating oil composition of  claim 1 .  
   
   
       20 . A method of lubricating a gasoline internal combustion engine comprising applying to said engine a lubricating oil composition of  claim 16.