Lubricant Providing Improved Cleanliness For Two-Stroke Cycle Engines

Abstract

A lubricant composition comprising an oil of lubricating viscosity, 0.1 to 2 percent by weight of a Mannich dispersant, and 0.1 to 2 percent by weight of a succinimide dispersant, wherein the succinimide dispersant provides at least about 40 parts per million by weight of nitrogen atoms to the lubricant composition, provides cleanliness to a two-stroke cycle engine.

1 . A lubricant composition comprising:
 (a) an oil of lubricating viscosity;   (b) about 0.1 to about 2 percent by weight of an ashless Mannich dispersant;   (c) about 0.1 to about 2 percent by weight of an ashless succinimide dispersant; and   (d) a metal-containing detergent in an amount to deliver about 0.01 to about 0.12 percent sulfated ash to the lubricant composition.   
       wherein the succinimide dispersant provides at least about 40 parts per million by weight of nitrogen atoms to the lubricant composition. 
     
     
         2 . (canceled) 
     
     
         3 . The lubricant composition of  claim 1  wherein the Mannich dispersant comprises the reaction product of a polyisobutene-substituted phenol, formaldehyde or a reactive equivalent of formaldehyde, and dimethylamine. 
     
     
         4 . The lubricant composition of  claim 1  wherein the amount of the Mannich dispersant is about 0.2 to about 1.05 percent by weight. 
     
     
         5 . The lubricant composition of  claim 1  wherein the succinimide dispersant is a condensation product of hydrocarbyl-substituted succinic anhydride or a reactive equivalent thereof, with a polyethylene polyamine. 
     
     
         6 . The lubricant composition of  claim 1  wherein the succinimide dispersant has a total base number of at least about 70 on an oil-free basis. 
     
     
         7 . The lubricant composition of  claim 1  wherein the succinimide dispersant has a total base number of at least about 90 on an oil-free basis. 
     
     
         8 . The lubricant composition of  claim 1  wherein the succinimide dispersant has a nitrogen content of at least about 3 percent by weight on an oil-free basis. 
     
     
         9 . The lubricant composition of  claim 1  wherein the amount of the succinimide dispersant is about 0.2 to about 1 percent by weight. 
     
     
         10 . (canceled) 
     
     
         11 . The lubricant composition of  claim 1  wherein the weight ratio of the Mannich dispersant to the succinimide dispersant is about 80:20 to about 20:80. 
     
     
         12 . The lubricant composition of  claim 1  wherein the metal-containing detergent is an overbased sulfonate, phenate, salicylate, or salixarate detergent. 
     
     
         13 . The lubricant composition of  claim 1  wherein the metal containing detergent comprises an overbased calcium phenate detergent. 
     
     
         14 . The lubricant composition of  claim 1  wherein the metal containing detergent contributes at least about 0.1 total base number to the lubricant composition. 
     
     
         15 . The lubricant composition of  claim 1  wherein the amount of phosphorus contained therein is 0 to 0.05 weight percent. 
     
     
         16 . The lubricant composition of  claim 15  wherein the amount of phosphorus is provided by one or more zinc dialkyldithiophosphates. 
     
     
         17 . A composition prepared by admixing the components of  claim 1 . 
     
     
         18 . A method of lubricating an internal combustion engine, comprising supplying thereto the lubricant composition of  claim 1 . 
     
     
         19 . The method of  claim 18  wherein the internal combustion engine is a two-stroke cycle engine. 
     
     
         20 . The method of  claim 18  wherein the internal combustion engine has a power output of less than 150 kW (201 horsepower). 
     
     
         21 . The method of  claim 18  wherein the internal combustion engine has a power output of 0.1 to 15 kW. 
     
     
         22 . The method of  claim 18  wherein the lubricant composition is provided as a mixture with a liquid fuel.