Lubricant composition suitable for engines fueled by alternate fuels

Abstract

A lubricant composition suitable for use in engines fueled by gasoline or biorenewable fuels or both, comprising an oil of lubricating viscosity and a dispersant system is disclosed herein. Also disclosed is an emulsion composition comprising a biorenewable fuel, an oil of lubricant viscosity, and a dispersant system. A method of reducing aqueous separation in an emulsion composition is also disclosed.

1 - 18 . (canceled) 
     
     
         19 . A method of reducing aqueous separation in an emulsion composition comprising:
 providing an emulsion composition comprising a fuel composition comprising a biorenewable fuel, water, and an oil of lubricating viscosity; and   providing to said emulsion composition a dispersant system consisting essentially of a first dispersant comprising at least one relatively low molecular weight hydrocarbyl-substituted succinimide; and a second dispersant comprising at least one relatively high molecular weight dispersant selected from the group consisting of hydrocarbyl-substituted succinimides, hydrocarbyl-substituted amines, or Mannich base adducts derived from a hydrocarbyl-substituted phenol condensed with an aldehyde and an amine,   
       wherein the hydrocarbyl substituent of each of the first and second dispersants comprises a polyisobutylene group having a number average molecular weight of 800 to 2500. 
     
     
         20 . (canceled) 
     
     
         21 . The method of  claim 19 , wherein the ratio of first dispersant to second dispersant ranges from about 1:3 to about 3:1. 
     
     
         22 . The method of  claim 19 , wherein the ratio of first dispersant to second dispersant ranges from about 1:1 to about 1:3. 
     
     
         23 - 25 . (canceled) 
     
     
         26 . The method of  claim 19 , wherein the ratio of hydrocarbyl substituent to succinic acid in the first dispersant ranges from about 1.0:1.0 to about 1:0:1.6. 
     
     
         27 . The method of  claim 19 , wherein at least one of the first and second dispersants is a post treated dispersant. 
     
     
         28 . The method of  claim 19 , wherein the emulsion composition comprises at least one additive selected from the group consisting of antiwear agents, detergent, diluents, defoamers, demulsifiers, anti-foam agents, corrosion inhibitors, extreme pressure agents, seal well agents, antioxidants, pour point depressants, rust inhibitors and friction modifiers. 
     
     
         29 . The method of  claim 19 , wherein the biorenewable fuel comprises an alcohol. 
     
     
         30 . A method of lubricating an engine operating a fuel composition containing a biorenewable fuel to prevent aqueous phase separation in an emulsion containing a lubricant, the fuel composition, and water, comprising:
 lubricating the engine with a lubricant composition comprising:   a dispersant system consisting essentially of a first dispersant comprising at least one relatively low molecular weight hydrocarbyl-substituted succinimide; and a second dispersant comprising at least one relatively high molecular weight dispersant selected from the group consisting of hydrocarbyl-substituted succinimides, hydrocarbyl-substituted amines, or Mannich base adducts derived from a hydrocarbyl-substituted phenol condensed with an aldehyde and an amine, wherein the hydrocarbyl substituent of each of the first and second dispersants comprises a polyisobutylene group having a number average molecular weight of 800 to 2500; and   operating the engine on the fuel composition.   
     
     
         31 . The method of  claim 30 , wherein the ratio of first dispersant to second dispersant ranges from about 1:3 to about 3:1. 
     
     
         32 . The method of  claim 30 , wherein the ratio of first dispersant to second dispersant ranges from about 1:1 to about 1:3. 
     
     
         33 . The method of  claim 30 , wherein the ratio of hydrocarbyl substituent to succinic acid in the first dispersant ranges from about 1.0:1.0 to about 1:0:1.6. 
     
     
         34 . The method of  claim 30 , wherein at least one of the first and second dispersants is a post treated dispersant. 
     
     
         35 . The method of  claim 30 , wherein the lubricant composition comprises at least one additive selected from the group consisting of antiwear agents, detergent, diluents, defoamers, demulsifiers, anti-foam agents, corrosion inhibitors, extreme pressure agents, seal well agents, antioxidants, pour point depressants, rust inhibitors and friction modifiers. 
     
     
         36 . The method of  claim 30 , wherein the biorenewable fuel comprises an alcohol.