Low Disperant Lubricant Composition

Abstract

The disclosed technology relates to lubricants for compression ignition internal combustion engines, particularly those demonstrating at least one of improved seals performance, reduced deposit formation, and excellent durability. The present invention provides a low dispersant lubricating composition comprising (a) an oil of lubricating viscosity, (b) about 0.5 weight percent to 3.0 weight percent of an oxyalkylated hydrocarbyl-substituted phenol compound, (c) about 0.01 weight percent to 2.6 weight percent of a polyalkenylsuccinimide dispersant, and (d) about 0.05 weight percent to 2.0 weight percent of a polyolefin dispersant viscosity modifier, and wherein the lubricating composition contains zinc in an amount less than about 700 ppm by weight of the composition.

1 . A low zinc lubricating composition comprising:
 an oil of lubricating viscosity;   0.5 weight percent to 3.0 weight percent of an oxyalkylated hydrocarbyl-substituted phenol compound;   0.01 weight percent to 2.6 weight percent of a polyalkenylsuccinimide dispersant; and   0.05 weight percent to 3.0 weight percent of a polyolefin dispersant viscosity modifier,   wherein the lubricating composition contains zinc in an amount less than 700 ppm by weight of the composition.   
     
     
         2 . The lubricating composition of  claim 1 , wherein the oxyalkylated hydrocarbyl phenol is represented by the formula: 
       
         
           
           
               
               
           
         
         wherein each R 2  is independently hydrogen or a hydrocarbyl group of 1 to 6 carbon atoms; R 3  is hydrogen, a hydrocarbyl group of 1 to 24 carbon atoms, an acyl group represented by —C(═O)R 5 , where R 5  is a hydrocarbyl group of 1 to 24 carbon atoms, or mixtures thereof; each R4 is independently a hydrocarbyl group of 1 to 225 carbon atoms, wherein at least one R4 contains 20 to 225 carbon atoms; n=1 to 20; and m=1 to 3. 
       
     
     
         3 . The lubricating composition of  claim 2 , wherein m=1; and R 4  is a hydrocarbyl group of 30 to 225 carbon atoms. 
     
     
         4 . The lubricating composition of  claim 1 , wherein n=2 to 10; at least one R 2  is methyl, and R 4  is a polyalk(en)yl group. 
     
     
         5 . The lubricating composition according to  claim 1 , wherein R 4  is a polyisobutenyl group having a molecular weight of 250 to 2500. 
     
     
         6 . The lubricating composition of  claim 1  wherein the polyalkenylsuccinimide dispersant wherein the polyolefin has a number average molecular weight of 850 to 5000 Daltons and a vinylidene content of at least 50 mol %. 
     
     
         7 . The lubricating composition of  claim 1 , wherein the polyalkenyl succinimide dispersant comprises a poyisobutylene succinimide compound. 
     
     
         8 . The lubricating composition of  claim 1 , wherein the polyolefin dispersant viscosity modifier comprises an ethylene-α-olefin copolymer grafted with a polar moiety. 
     
     
         9 . The lubricating composition of  claim 8  wherein the ethylene-α-olefin copolymer has a number-average molecular weight (Mn) of 4500 Da to 120,000 Da. 
     
     
         10 . The lubricating composition of  claim 1  wherein the polar moiety of the ethylene-α-olefin copolymer comprises an acyl group 
     
     
         11 . The lubricating composition of  claim 3  wherein the ethylene-α-olefin copolymer is further functionalized with a hydrocarbyl amine or hydrocarbyl alcohol capable of reacting with the acyl group to form an amide, imide, or ester linkage. 
     
     
         12 . The lubricating composition of  claim 1  comprising a phosphorus anti-wear agent. 
     
     
         13 . The lubricating composition of  claim 1 , comprising a zinc dialkyldithiophosphate in an amount to deliver 0.01 weight percent to 0.06 weight percent zinc to the lubricating composition. 
     
     
         14 . The lubricating composition of  claim 1 , further comprising a metal containing detergent. 
     
     
         15 . The lubricating composition of  claim 14 , wherein the metal containing detergent is selected from the group consisting of non-sulphur containing phenates, sulphur containing phenates, sulphonates, salixarates, saligenins, salicylates, and mixtures thereof. 
     
     
         16 . The lubricating composition of  claim 14 , wherein the metal-containing detergent comprises an alkaline earth metal detergent. 
     
     
         17 . The lubricating composition of  claim 16 , wherein the metal containing detergent comprises a calcium or magnesium containing sulfonate detergent. 
     
     
         18 . The lubricating composition of  claim 12 , wherein the metal containing sulfonate is present at 0.1 to 10 weight % of the composition. 
     
     
         19 . The lubricating composition of  claim 14 , wherein the metal containing sulfonate detergent has a metal ratio of at least 8. 
     
     
         20 . The lubricating composition of  claim 1 , further comprising an ashless antioxidant in an amount 0.5 weight percent to 6 weight percent of the composition. 
     
     
         21 . The lubricating composition of  claim 20 , wherein the ashless antioxidant is selected from group consisting of 2,6-dihydrocarbyl phenol compounds, diarylamine compounds, sulfurized olefin compounds, or mixtures thereof. 
     
     
         22 . The lubricating composition of  claim 1  comprising at least one of a friction modifier, antiwear agent, viscosity modifier, additional overbased salt, and corrosion inhibitor. 
     
     
         23 . A method of lubricating a light duty compression-ignition internal combustion engine, comprising supplying to said engine a lubricant composition a lubricating composition of  claim 1 . 
     
     
         24 . A method of reducing deposit formation in a light-duty compression ignition internal combustion engine, comprising:
 operating said engine with a lubricant composition comprising:
 an oil of lubricating viscosity; 
 0.5 weight percent to 3.0 weight percent of an oxyalkylated hydrocarbyl-substituted phenol compound; 
 0.01 weight percent to 2.6 weight percent of a polyalkenylsuccinimide dispersant; and 
 0.05 weight percent to 2.0 weight percent of a polyolefin dispersant viscosity modifier, 
 wherein the lubricating composition contains zinc in an amount less than 700 ppm by weight of the composition.