Lubricating oil composition

Abstract

A low SAPS lubricating oil composition exhibiting having up to 0.3 wt. % sulfur, up to 0.08 wt. % phosphorus, and a sulfated ash content up to 0.80 wt. % comprising a nitrogen-containing ashless dispersant, a boron source, the wt. % N to wt. % B ratio being 3:1 to 5:1.

1 . A lubricating oil composition having a sulfur content of up to 0.3 wt. %, a phosphorus content of up to 0.08 wt. %, a sulfated ash content of up to 0.80 wt. % which comprises an admixture of: 
 (a) a major amount of an oil of lubricating viscosity    (b) at least one nitrogen-containing dispersant, the dispersant providing to the oil a nitrogen content of at least 0.075 wt. % nitrogen, the dispersant having a polyalkenyl backbone which has a molecular weight range of about 900 to 3000, and    (c) an oil soluble or oil dispersible source of boron, present in an amount so as to provide a ratio of wt. % nitrogen to wt. % boron in the oil composition of about 3:1 to 5:1.    
     
     
         2 . The composition of  claim 1 , further comprising one or more of a member of the group consisting of an overbased metal containing detergent, an antioxidant, a zinc dihydrocarbyl dithiophosphate, oil soluble organomolybdenum compounds, friction modifiers and viscosity modifiers.  
     
     
         3 . The composition of  claim 2 , wherein the detergent is calcium alkyl salicylate of TBN 200-400.  
     
     
         4 . The composition of  claim 1 , wherein the dispersant is a polyisobutenyl succinimide.  
     
     
         5 . The composition of  claim 1 , wherein the boron compound is a separately added borated polyisobutenyl succinimide dispersant.  
     
     
         6 . The composition of  claim 2 , comprising an antioxidant that is (i) a dialkyl diphenylamine wherein the alkyl is C 4 -C 20  alkyl a (ii) a hindered phenol or a mixture thereof.  
     
     
         7 . The composition of  claim 2 , wherein the hydrocarbyl groups of the zinc dihydrocarbyl dithiophosphate have 2 to 8 carbon atoms  
     
     
         8 . The composition of  claim 2 , wherein the organomolybdenum compound is a dialkyldithiocarbamate  
     
     
         9 . The composition of  claim 1 , wherein the oil of lubricating viscosity is a mineral oil.