Lubricating oil composition

Abstract

A lubricating oil composition for internal combustion engines which has a sulphated ash content of not greater than 0.9 wt. % and a phosphorus content in the range of from 0.04 to 0.1 wt. % is provided. The composition contains base oil, one or more detergents selected from phenate detergents, salicylate detergents and sulphonate detergents, wherein said one or more detergents each, independently, have a TBN (total base number) value in the range of from 30 to 350 mg.KOH/g, as measured by ISO 3771; and at least 3.5 wt. % of one or more antioxidants selected from the group of aminic antioxidants and/or phenolic antioxidants, based on the total weight of the lubricating oil composition.

1 . A lubricating oil composition for internal combustion engines having a sulphated ash content of not greater than 0.9 wt. % and a phosphorus content in the range of from 0.04 to 0.1 wt. %, comprising 
 (a) a base oil,    (b) at least one detergent selected from the group consisting of phenate detergents, salicylate detergents and sulphonate detergents, wherein said detergent each, independently, have a TBN (total base number) value in the range of from 30 to 350 mg.KOH/g, as measured by ISO 3771; and    (c) at least 3.5 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 3.7 wt. %, based on the total weight of the lubricating oil composition.  
     
     
         3 . The lubricating oil composition of  claim 1  wherein said antioxidant comprise aminic antioxidants.  
     
     
         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 composition of  claim 1  wherein said antioxidant comprise phenolic antioxidants.  
     
     
         6 . The lubricating oil composition of  claim 5  wherein said phenolic antioxidant is selected from the group consisting of 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).  
     
     
         7 . The lubricating oil composition of  claim 1  wherein said composition has a sulphur content of not greater than 1.2 wt. %, based on the total weight of the lubricating oil composition.  
     
     
         8 . The lubricating oil composition of  claim 1  wherein said composition has a phosphorus content in the range of from 0.04 to 0.09 wt. %, based on the total weight of the lubricating oil composition.  
     
     
         9 . The lubricating oil composition of  claim 1  having a TBN level of at least 5.0 mg.KOH/g, as measured by ISO 3771, in an internal combustion engine in the VW T4 test (PV 1449).  
     
     
         10 . A method of lubricating an internal combustion engine comprising applying a lubricating oil composition of  claim 1  thereto.