Lubricating oil composition

Abstract

A lubricating oil composition for internal combustion engines which composition is phosphorus-free is provided. The lubricating oil composition contains at least 60% wt. of base oil selected from Group I, Group II, Group III and Group IV base oils or mixtures thereof, and at least 1.4% wt. of one or more antioxidants selected from aminic antioxidants and/or phenolic antioxidants, based on the total weight of the lubricating oil composition.

1 . A lubricating oil composition useful for internal combustion engines which composition is phosphorus-free, said composition comprising at least 60% wt. of base oil selected from the group consisting of Group I, Group II, Group III and Group IV base oils or mixtures thereof, and at least 1.4% wt. of at least one antioxidant selected from the group consisting of aminic antioxidants, phenolic antioxidants and mixtures thereof, based on the total weight of the lubricating oil composition.  
     
     
         2 . The lubricating oil composition of  claim 1  wherein said antioxidant is present in an amount of at least 1.6% wt., based on the total weight of the lubricating oil composition.  
     
     
         3 . The lubricating oil composition of  claim 1  wherein said antioxidant is an aminic antioxidant.  
     
     
         4 . The lubricating oil composition of  claim 3  wherein said aminic antioxidant is selected from the group consisting of alkylated diphenylamines, phenyl-α-naphthylamines, phenyl-β-naphthylamines and alkylated α-naphthylamines.  
     
     
         5 . The lubricating oil of  claim 2  wherein said antioxidant is an aminic antioxidant.  
     
     
         6 . The lubricating oil composition of  claim 1  wherein said antioxidant is a phenolic antioxidant.  
     
     
         7 . The lubricating oil composition of  claim 5  wherein said phenolic antioxidants are selected from 2,6-di-t-butylphenol, C7-C9 branched alkyl esters of 3,5-bis(1,1-dimethyl-ethyl)-4-hydroxy-benzenepropanoic acid, and 4,4′-methylenebis(2,6-di-t-butylphenol).  
     
     
         8 . The lubricating oil composition of  claim 2  wherein said antioxidant is a phenolic antioxidant.  
     
     
         9 . A method of lubricating an internal combustion engine comprising applying a lubricating oil composition of  claim 1  to a portion of the internal combustion engine.  
     
     
         10 . The method of  claim 9  wherein the internal combustion engine is a camless internal combustion engine.