Method of Lubricating an Internal Combustion Engine

Abstract

The invention provides a method of lubricating an internal combustion engine comprising supplying to said engine a dispersion, the dispersion comprises: (a) a metal base; (b) a surfactant; and (c) an organic medium in which the metal base is uniformly dispersed by physical processes, wherein the metal base has a mean average particle size of at least 10 nanometres to less than 1 μm; and the dispersion has a solids content of greater than 15 wt %. The invention further provides a lubricant composition containing said dispersion.

1 . A method of lubricating an internal combustion engine comprising supplying to said engine a dispersion, the dispersion comprising: (a) a metal base; (b) a surfactant; and (c) an organic medium in which the metal base is uniformly dispersed by physical processes, wherein the metal base has a mean average particle size of at least 10 nanometres to less than 1 μm; and the dispersion has a solids content of greater than 15 wt %. 
     
     
         2 . The method of  claim 1 , wherein the dispersion has total base number ranging from 200 to 1750. 
     
     
         3 . The method of  claim 1 , wherein the dispersion is semi-translucent to translucent or transparent. 
     
     
         4 . The method of  claim 1 , wherein the physical processes for preparing the dispersion comprise milling in a vertical or horizontal bead mill. 
     
     
         5 . The method of  claim 1 , wherein the metal base is present at 25 wt % to 80 wt %, or from 35 wt % to 70 wt % of the dispersion. 
     
     
         6 . The method of  claim 1 , wherein the metal of the metal base comprises a monovalent or divalent metal. 
     
     
         7 . The method of  claim 1 , wherein the metal comprises lithium, potassium, sodium, copper, zinc, magnesium, calcium, barium or mixtures thereof. 
     
     
         8 . The method of  claim 1 , wherein the metal comprises calcium. 
     
     
         9 . The method of  claim 1 , wherein the metal base has a mean average particle size of 30 nanometres to 0.7 μm. 
     
     
         10 . The method of  claim 1 , wherein the base of the metal base comprises at least one of oxides, hydroxides or carbonates. 
     
     
         11 . The method of  claim 1 , wherein the metal base comprises sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, sodium hydroxide, potassium hydroxide, anhydrous lithium hydroxide, lithium hydroxide monohydrate, magnesium hydroxide, calcium hydroxide, lithium carbonate, calcium carbonate, copper acetate, magnesium carbonate, calcium oxide, magnesium oxide, lithium oxide, cerium oxide, iron oxide or mixtures thereof. 
     
     
         12 . The method of  claim 1 , wherein the surfactant has a hydrophilic lipophilic balance (HLB) ranging from 1 to 40. 
     
     
         13 . The method of  claim 1 , wherein the surfactant comprises at least one of hydrocarbyl substituted aryl sulphonic acids, polyolefin-substituted acylating agents, or salixarenes. 
     
     
         14 . The method of  claim 1 , wherein the organic medium comprises an oil of lubricating viscosity. 
     
     
         15 . The method of  claim 1 , wherein the dispersion comprises: (a) 40-65 wt % of a metal base; (b) 5-25 wt % of a surfactant; and (c) an organic medium in which the metal base is uniformly dispersed by physical processes. 
     
     
         16 . A lubricant composition comprising (i) a dispersion comprising: (a) a metal base; (b) a surfactant; and (c) an organic medium in which the metal base is uniformly dispersed by physical processes, wherein the metal base has a mean average particle size of at least 10 nanometres to less than 1 μm; and the dispersion has a solids content of greater than 15 wt %; (ii) an oil of lubricating viscosity; and (iii) other performance additives. 
     
     
         17 . The lubricant composition of  claim 16 , wherein the other performance additives comprise at least one of metal deactivators, detergents, dispersants, viscosity modifiers, friction modifiers, corrosion inhibitors, dispersant viscosity modifiers, extreme pressure agents, antiscuffing agents, antioxidants, foam inhibitors, demulsifiers, pour point depressants, seal swelling agents and mixtures thereof. 
     
     
         18 . The lubricant composition of  claim 16 , wherein (i) the dispersion is present at 0.5-10 wt % (ii) the oil of lubricating viscosity is present at 70-99.4 wt %; and (iii) the other performance additives are present at 0.01-25 wt % of the lubricant composition.