Mixed TBN detergents and lubricating oil compositions containing such detergents

Abstract

The present invention concerns a detergent additive for lubricating oil compositions comprising at least two of low, medium, and high TBN detergents. Preferably the detergent is a calcium salicylate. The present invention also concerns lubricating oil compositions comprising such detergents, and at least one of Group II base stock, Group III base stock, or wax isomerate base stock.

What is claimed is:  
     
         1 . A detergent additive for use in a lubricating oil composition comprising at least two detergents selected from a group consisting of: 
 (a) a first detergent having a TBN of over about 200,    (b) a second detergent having a TBN between about 100 and 200; and    (c) a third detergent having a TBN less than about 100.    
     
     
         2 . The detergent additive of  claim 1  wherein any one or all of said first, second and third detergents is a calcium salicylate detergent.  
     
     
         3 . The detergent additive of  claim 1  comprising said first detergent, said second detergent and said third detergent.  
     
     
         4 . A lubricating oil composition which comprises: 
 (a) an oil of lubricating viscosity; and    (b) at least two detergents selected from a group consisting of: 
 (i) a first detergent having a TBN of over about 200,  
 (ii) a second detergent having a TBN between about 100 and 200; and  
 (iii) a third detergent having a TBN less than about 100.  
   
     
     
         5 . The lubricating oil composition of  claim 4  any one or all of said first, second and third detergents is a salicylate detergent.  
     
     
         6 . The lubricating oil composition of  claim 4  wherein said lubricating composition contains said first detergent, said second detergent and said third detergent.  
     
     
         7 . The lubricating oil composition of  claim 4  through  claim 6  further comprising a hydrocarbyl aromatic fluid.  
     
     
         8 . The lubricating oil composition of  claim 7  wherein the salicylate detergent is a calcium salicylate.  
     
     
         9 . The lubricating oil composition of  claim 8  wherein the oil of lubricating viscosity has a viscosity index of about 110 or greater.  
     
     
         10 . The lubricating oil composition of  claim 9  wherein the oil of lubricating viscosity is at least one item selected from the group consisting of Group II base stocks, Group III base stocks, Group IV base stocks, and wax isomerates, and mixtures thereof.  
     
     
         11 . The lubricating oil composition of  claim 10  wherein the wax isomerate base stock is a hydroisomerized Fischer-Tropsch wax.  
     
     
         12 . The lubricating oil composition of  claim 10  wherein the salicylates are each present in an amount of about 0.2 to about 4 weight percent of the lubricating oil composition on an active ingredient basis, and the hydrocarbyl aromatic fluid is present in an amount of about 3 to 30 weight percent of the lubricating oil composition.  
     
     
         13 . The lubricating oil composition of  claim 12  wherein the salicylates are each present in an amount of about 0.25 to about 2 weight percent of the lubricating oil composition on an active ingredient basis, and the hydrocarbyl aromatic fluid is present in an amount of about 4 to 20 weight percent of the lubricating oil composition.  
     
     
         14 . The lubricating oil composition of  claim 13  wherein at least 20 weight percent of the lubricating oil composition is comprised of at least one item selected from a group consisting of Group II base stocks, Group III base stocks, and wax isomerate base stocka and mixtures thereof.  
     
     
         15 . The lubricating oil composition of  claim 14  wherein at least 30 weight percent of the lubricating oil composition is comprised of at least one item selected from a group consisting of Group II base stocks, Group III base stocks, and wax isomerate base stocka and mixtures thereof.  
     
     
         16 . The lubricating oil composition of  claim 15  wherein at least 80 weight percent of the lubricating oil composition is comprised of at least one item selected from a group consisting of Group II base stocks, Group III base stocks, and wax isomerate base stocka and mixtures thereof.  
     
     
         17 . A method for improving the viscosity increase of a lubricating oil composition in a 3-hour Noack test comprising the step of adding to an oil of lubricating viscosity at least two items selected from a group consisting of: 
 (i) a first salicylate detergent having a TBN of over about 200,    (ii) a second salicylate detergent having a TBN between about 100 and 200; and    (iii) a third salicylate detergent having a TBN less than about 100.    
     
     
         18 . A method for improving piston cleanliness and ring sticking of a lubricating oil composition comprising the step of adding to an oil of lubricating viscosity at least two items selected from a group consisting of: 
 (i) a first salicylate detergent having a TBN of over about 200,    (ii) a second salicylate detergent having a TBN between about 100 and 200; and    (iii) a third salicylate detergent having a TBN less than about 100.    
     
     
         19 . A method for improving film forming tendency of a lubricating oil composition comprising the step of adding to an oil of lubricating viscosity at least two items selected from a group consisting of: 
 (i) a first salicylate detergent having a TBN of over about 200,    (ii) a second salicylate detergent having a TBN between about 100 and 200; and    (iii) a third salicylate detergent having a TBN less than about 100.    
     
     
         20 . A method for improving frictional properties of a lubricating oil composition comprising the step of adding to an oil of lubricating viscosity at least two items selected from a group consisting of:a first salicylate detergent having a TBN of over about 200, (ii) a second salicylate detergent having a TBN between about 100 and 200; and 
 (iii) a third salicylate detergent having a TBN less than about 100.