Lubricating compositions

Abstract

A lubricating oil composition, comprising as an ester additive component, one or more esters of glycerol and a carboxylic acid such as oleic acid having a defined proportion of monoester, diester and/or triester and an oil-soluble molybdenum compound, which may a trinuclear molybdenum compound.

1 . A composition comprising: 
 (A) oil of lubricating viscosity;    (B) as an ester additive component, one or more esters of glycerol and a carboxylic acid containing 12 to 30 carbon atoms and 0 to 3 carbon-carbon double bonds wherein less than 50% by mass of the component is one or more monoesters; and    (C) as a further additive component, an oil-soluble molybdenum compound.    
   
   
       2 . A composition as claimed in  claim 1  wherein 40% by mass or less of the ester additive component is one or more monoesters.  
   
   
       3 . A composition as claimed in  claim 1  wherein the carboxylic acid is a saturated or unsaturated C16 to C18 fatty acid, such as oleic acid.  
   
   
       4 . A composition as claimed in  claim 1  wherein the oil-soluble molybdenum compound is a trinuclear molybdenum compound.  
   
   
       5 . A composition as claimed in  claim 1 , further comprising one or more co-additives, different from (B) and (C), selected from ashless dispersants, metal detergents, corrosion inhibitors, metal dihydrocarbyl dithiophosphates, antioxidants, pour point depressants, additional friction modifiers, antifoam agents and viscosity modifiers.  
   
   
       6 . A lubricating oil concentrate comprising: 
 (A) oil of lubricating viscosity;    (B) as an ester additive component, one or more esters of glycerol and a carboxylic acid containing 12 to 30 carbon atoms and 0 to 3 carbon-carbon double bonds wherein less than 50% by mass of the component is one or more monoesters; and    (C) as a further additive component, an oil-soluble molybdenum compound.    
   
   
       7 . A concentrate as claimed in  claim 6  wherein the oil of lubricating viscosity is present in an amount of from 30 to 70 mass %.  
   
   
       8 . A method for reducing friction in an internal combustion engine at an operating temperature in excess of 90° C., comprising operating the engine and lubricating the engine with a composition as claimed in  claim 1  and operating the lubricated engine.  
   
   
       9 . A method of enhancing the friction-modification properties of a lubricating oil composition in the lubrication of an internal combustion engine at operating temperatures in excess of 90° C., comprising formulating said lubricating oil composition with a combination of: 
 (B) as an ester additive component, one or more esters of glycerol and a carboxylic acid containing 12 to 30 carbon atoms and 0 to 3 carbon-carbon double bonds wherein less than 50% by mass of the component is one or more monoesters; and    (C) as a further additive component, an oil-soluble molybdenum compound.    
   
   
       10 . A composition comprising: 
 (A) oil of lubricating viscosity;    (B) as an ester additive component, one or more esters of glycerol and a carboxylic acid containing 12 to 30 carbon atoms and 0 to 3 carbon-carbon double bonds wherein less than 55% by mass of the component is one or more monoesters; and    (C) as a further additive component, an oil-soluble tri-nuclear molybdenum compound.    
   
   
       11 . A composition as claimed in  claim 10  wherein 40 mass % or less of the ester additive component is one or more monoesters.  
   
   
       12 . A composition as claimed in  claim 10  wherein the carboxylic acid is a saturated or unsaturated C16 to C18 fatty acid, such as oleic acid.  
   
   
       13 . A composition as claimed in  claim 10  wherein the oil of lubricating viscosity is present in a concentrate-forming amount.  
   
   
       14 . A composition as claimed in  claim 13  wherein the concentrate-forming amount is from 30 to 70 mass %.  
   
   
       15 . A composition as claimed in  claim 10  further comprising one or more co-additives, different from (B) and (C), selected from ashless dispersants, metal detergents, corrosion inhibitors, metal dihydrocarbyl dithiophosphates, antioxidants, pour point depressants, additional friction modifiers, antifoam agents and viscosity modifiers.  
   
   
       16 . A method for reducing friction in an internal combustion engine at an operating temperature in excess of 90° C., comprising operating the engine and lubricating the engine with a composition as claimed in  claim 10  and operating the lubricated engine.  
   
   
       17 . A method as claimed in  claim 16  wherein the high temperature is in excess of 90° C.  
   
   
       18 . A method of enhancing the friction-modification properties of a lubricating oil composition in the lubrication of an internal combustion engine at operating temperatures in excess of 90° C., comprising formulating said lubricating oil composition with a combination of: 
 (B) as an ester additive component, one or more esters of glycerol and a carboxylic acid containing 12 to 30 carbon atoms and 0 to 3 carbon-carbon double bonds wherein less than 55% by mass of the component is one or more monoesters; and    (C) as a further additive component, an oil-soluble tri-nuclear molybdenum compound.