Lacquer reducing lubricating oil composition and method of use of same

Abstract

This invention relates to lubricating oil compositions that have surprisingly been shown to reduce the formation of lacquer deposits in engines. More specifically, this invention relates to a lubricating oil for natural gas engines that reduces siloxane-related cylinder liner lacquer deposits.

What is claimed is:  
     
         1 . A lubricating oil composition comprising: 
 (a) at least about 20 wt % of at least one base oil of lubricating viscosity selected from the group consisting of Group II, Group III and Group IV base stocks;    (b) a diarylamine;    (c) an alkaline earth metal phenate;    (d) an alkali earth metal sulfonate;    (e) a borated aminated hydrocarbyl succinic derivative.    
     
     
         2 . The lubricant oil of  claim 1  wherein the diarylamine is an alkylated diphenyl amine provided to said composition in a concentration of about 0.05 to2.0 wt %.  
     
     
         3 . The lubricant oil of  claim 1  wherein the diarylamine is an alkylated diphenyl amine provided to said composition in a concentration of about 0.2 to 0.75 wt %.  
     
     
         4 . The lubricant oil of  claim 1  wherein the alkaline earth metal phenate is a calcium based phenate provided to said composition in a concentration of about 0.05 to 5.0 wt %.  
     
     
         5 . The lubricant oil of  claim 1  wherein the alkaline earth metal phenate is a calcium based phenate provided to said composition in a concentration of about 0.9 to 2.7 wt %.  
     
     
         6 . The lubricant oil of  claim 1  wherein the alkali earth metal sulfonate is a calcium sulfonate provided to said composition in a concentration of about 0.5 to 5.0 wt %.  
     
     
         7 . The lubricant oil of  claim 6  wherein the calcium sulfonate is a neutral calcium sulfonate provided to said composition in a concentration of about 0.5 to 1.0 wt %.  
     
     
         8 . The lubricant oil of  claim 1  wherein said borated aminated hydrocarbyl succinic derivative is derived from succinic anhydride and provided to said composition in a concentration of about 1.0 to 10.0 wt %.  
     
     
         9 . The lubricant oil of  claim 8  wherein the borated aminated polybutenyl succinic anhydride is provided to said composition in a concentration of about 1.75 to 3.0 wt %.  
     
     
         10 . The lubricant oil of  claim 1  wherein 
 said diarylamine is an alkylated diphenyl amine provided to said composition in a concentration of about 0.05 to 2.0 wt %,  
 said alkaline earth metal phenate is a calcium based phenate provided to said composition in a concentration of about 0.05 to 5.0 wt %,  
 said alkaline earth metal sulfonate is a calcium sulfonate provided to said composition in a concentration of about 0.5 to 5.0 wt %,  
 said borated aminated hydrocarbyl succinic derivative is derived from succinic anhydride and provided to said composition in a concentration of about 1.0 to 10.0 wt %.  
 
     
     
         11 . The lubricant oil of  claim 1  wherein 
 said diarylamine is an alkylated diphenyl amine provided to said composition in a concentration of about 0.2 to 0.75 wt %,  
 said alkaline earth metal phenate is a calcium based phenate provided to said composition in a concentration of about 0.9 to 2.7 wt %,  
 said alkaline earth metal sulfonate is a calcium sulfonate provided to said composition in a concentration of about 0.5 to 1.0 wt %,  
 said borated aminated hydrocarbyl succinic derivative is derived from succinic anhydride and provided to said composition in a concentration of about 1.75 to 3.0 wt %.  
 
     
     
         12 . A method of reducing lacquer in natural gas engines comprising employing the lubricant of  claim 1 .  
     
     
         13 . A method of reducing lacquer in natural gas engines comprising employing the lubricant of  claim 10 .  
     
     
         14 . A method of reducing lacquer in natural gas engines comprising employing the lubricant of  claim 11 .  
     
     
         15 . A lubricant oil composition comprising: 
 (a) at least about 20 wt % of at least one base oil of lubricating viscosity selected from the group consisting of Group II, Group III and Group IV base stocks;    (b) about 0.20 to about 0.75 wt % of an alkylated diphenyl amines;    (c) about 0.9 to about 2.7 wt % of at least one overbased alkali-metal phenate sulfide;    (d) about 0.50 to about 1.0 wt % of neutral alkali-metal sulfonate; and    (e) about 1.75 to about 3.0 wt % of a borated aminated hydrocarbyl succinic derivative which is derived from a succinic anhydride    
     
     
         16 . A method of reducing lacquer in natural gas engines comprising employing a lubricant oil composition comprising: 
 (a) at least about 20 wt % of at least one base oil of lubricating viscosity selected from the group consisting of Group II, Group III and Group IV base stocks;    (b) about 0.20 to about 0.75 wt % of an alkylated diphenyl amines;    (c) about 0.9 to about 2.7 wt % of at least one overbased alkali-metal phenate sulfide;    (d) about 0.5 to about 1.0 wt % of neutral alkali-metal sulfonate; and    (e) about 1.75 to about 3.0 wt % of a borated aminated hydrocarbyl succinic derivative which is derived from a succinic anhydride    
     
     
         17 . An additive for use in a lubricating oil composition which contains at least about 20 wt % of a non Group I base oil, said additive comprising: 
 (a) a diarylamine;    (b) an alkaline earth metal phenate;    (c) an alkaline earth metal sulfonate; and    (d) a borated aminated hydrocarbyl succinic derivative