High performance non-zinc, zero phosphorus engine oils for internal combustion engines

Abstract

A substantially zinc and phosphorous free lubricating oil meeting engine performance requirements contain an additive system containing metal detergents, at least one borated ashless dispersant, at least an amine antioxidant and a trinuclear molybdenum compound. The lubricant contains a minimum of 120 ppm boron and a minimum of 80 ppm molybdenum.

1 . A lubricating oil composition having less than about 2000 ppm sulfur and substantially free of zinc and phosphorus comprising: 
 (a) a major amount of a base oil of lubricating viscosity; and    (b) an effective amount of an additive system comprising: 
 (i) a metal detergent or mixture of metal detergents;  
 (ii) an ashless dispersant or mixture of dispersants, at least one of which is a borated ashless dispersant;  
 (iii) an ashless aminic antioxidant or mixture of antioxidants containing at least an aminic antioxidant; and  
 (iv) an oil soluble, phosphorous free, trinuclear molybdenum compound.  
   (c) with the proviso that the composition have a minimum of 120 ppm boron and a minimum of 80 ppm molybdenum.    
     
     
         2 . The composition of  claim 1  wherein the composition has a B:Mo:N ratio in the range of about 3:5:7 to about 5:1:18.  
     
     
         3 . The composition of  claim 2  wherein the additive system includes a mixture of alkaline metal detergents selected from the group consisting of calcium and magnesium sulfonates, phenates, salicylates and mixtures thereof in the amount of about 1.5 to about 6.0 wt % based on the total weight of the composition.  
     
     
         4 . The composition of  claim 3  including a mixture of borated and non-borated dispersants in the weight ratio of 1:9 to 9:1 and wherein the total amount of ashless dispersant is in the range of about 2.0 wt % to about 12.0 wt % based on the total weight of the composition.  
     
     
         5 . The composition of  claim 4  includes a mixture of phenolic and amine antioxidants in the weight ratio of about 1.0:9.0 to about 9.0:1.6 and wherein the total amount is in the range of about 0.25 wt % to about 2.5 wt % based on the total weight of the composition and wherein the trinuclear molybdenum compound is present in an amount of from about 0.05 wt % to about 1.50 wt %, based on the total weight of the composition.  
     
     
         6 . In the lubrication of an engine combusting a fuel containing below about 350 ppm sulfur, the improvement wherein the engine is lubricated with a composition comprising: 
 (a) a major amount of a base oil of lubricating viscosity; and    (b) an effective amount of an additive system comprising, 
 (i) a metal detergent or mixture of metal detergents;  
 (ii) an ashless dispersant or mixture of dispersants, at least one of which is a borated ashless dispersant;  
 (iii) an ashless aminic antioxidant or mixture of antioxidants containing at least an aminic antioxidant; and  
 (iv) an oil soluble, phosphorous free, trinuclear molybdenum compound.  
   (c) with the proviso that the composition have a minimum of 120 ppm boron and a minimum of 80 ppm molybdenum.    
     
     
         7 . The improvement of  claim 6  wherein the composition has a B:Mo:N ratio in the range of about 3:5:7 to about 5:1:18.  
     
     
         8 . The improvement of  claim 7  wherein the additive system includes a mixture of alkaline metal detergents selected from the group consisting of calcium and magnesium sulfonates, phenates, salicylates and mixtures thereof in the amount of about 1.5 to about 6.0 wt % based on the total weight of the composition.  
     
     
         9 . The improvement of  claim 8  wherein including a mixture of borated and non-borated dispersants in the weight ratio of 1:9 to 9:1 and wherein the total amount of ashless dispersant is in the range of about 2.0 wt % to about 12.0 wt % based on the total weight of the composition.  
     
     
         10 . The improvement of  claim 9  wherein includes a mixture of phenolic and amine antioxidants in the weight ratio of about 1.0:9.0 to about 9.0:1.6 and wherein the total amount is in the range of about 0.25 wt % to about 2.5 wt % based on the total weight of the composition and wherein the trinuclear molybdenum compound is present in an amount of from about 0.05 wt % to about 1.50 wt %, based on the total weight of the composition.