Reduced engine deposits from dispersant treated with copper

Abstract

The invention provides a lubricating composition containing an oil of lubricating viscosity and a dispersant treated with copper reagent. The invention further relates to methods of lubricating an internal combustion engine by supplying the described lubricating composition to the internal combustion engine. The invention further relates to the use of a dispersant treated with copper to reduce deposits on the inner surfaces of engine components.

What is claimed: 
     
         1 . An internal combustion engine lubricant composition comprising;
 a) an oil of lubricating viscosity,   b) about 0.5 to 10 wt. % of a metal substituted dispersant based on the weight of said engine oil lubricant composition,   c) an antioxidant,   d) an antiwear additive,   
       wherein the metal of the metal dispersant comprises copper and the amount of metal substituted dispersant is such to provide about 5 to 500 ppm of copper to said engine lubricant composition and wherein the lubricant composition comprises sulfur in an amount of less than 1 wt. % and phosphorus in an amount of less than 0.2 wt .% based on the weight of said lubricant composition. 
     
     
         2 . A composition according to  claim 1 , wherein said metal substituted dispersant is present from about 1 to about 6 wt. % of said lubricant composition. 
     
     
         3 . A composition according to  claim 1 , wherein said copper is present from about 5 to about 100 ppm in said engine lubricant composition. 
     
     
         4 . A composition according to  claim 1 , wherein said copper is present from about 40 to about 200 ppm in said engine lubricant composition. 
     
     
         5 . A composition according to  claim 1 , wherein said metal substituted dispersant is present from about 1.5 to about 3.5 wt. % in said engine lubricant composition. 
     
     
         6 . A composition according to  claim 1 , wherein said metal substituted dispersant is a metal substituted succinimide dispersant. 
     
     
         7 . A composition according to  claim 1 , further comprising an overbased detergent. 
     
     
         8 . A composition according to  claim 1 , wherein said antioxidant comprises an aminic antioxidant and/or a phenolic antioxidant. 
     
     
         9 . A composition according to  claim 8 , wherein said aminic antioxidant is present in an amount from about 0.1 to about 10 wt. % based on said lubricant composition. 
     
     
         10 . A composition according to  claim 8 , wherein said phenolic antioxidant is present in an amount from about 0.1 to about 10 wt. % based on said lubricant composition. 
     
     
         11 . A composition according to  claim 1 , wherein said anti-wear agent is a metal dithiophosphate antiwear agent. 
     
     
         12 . A composition according to  claim 1 , wherein the lubricant composition comprises sulfur in an amount of less than 0.8 wt. % and phosphorus in an amount of less than 0.1 wt. % based on the weight of said lubricant composition. 
     
     
         13 . A composition according to  claim 1 , wherein the lubricant composition comprises molybdenum in an amount of less than 100 parts per million parts in weight/weight (ppm), and boron in the amount of less than 100 ppm all based on the weight of the lubricant composition. 
     
     
         14 . A method of using an ashless dispersant reacted with a copper compound as an additive in a lubricating composition to reduce engine deposits when said lubricant is exposed to use at temperatures of 150° C. or more wherein the amount of said ashless dispersant reacted with said copper compound is present in an amount to provide about 5 to 500 ppm of copper to said lubricating composition and wherein the lubricating composition comprises sulfur in an amount of less than 1 wt. % and phosphorus in an amount of less than 0.2 wt. % based on the weight of said lubricating composition. 
     
     
         15 . A method of using an ashless dispersant according to  claim 14 , wherein said temperature is 200° C. or more.