Lubricant compositions for high efficiency engines

Abstract

The instant disclosure is directed to a method of lubricating a sump-lubricated, high efficiency, gasoline-fueled internal combustion engine. Said method involves supplying to the engine a lubricating composition comprising an oil of lubricating viscosity, an anti-wear agent, an ashless antioxidant, a metal-containing detergent, an ashless polyolefin dispersant, and (f) a polymeric viscosity modifier. The disclosure further provides a method of operating a high efficiency sump-lubricated gasoline-fueled internal combustion engine while maintaining or improving at least one of durability, deposit control, oxidation control, fuel economy, and resistance to knock and stochastic pre-ignition.

1 . A method of lubricating an internal combustion engine, comprising supplying to a sump-lubricated, high efficiency, gasoline-fueled internal combustion engine a lubricating composition comprising (a) an oil of lubricating viscosity, (b) an anti-wear agent in an amount 0.15 weight percent to 6 weight percent of the composition, (c) an ashless antioxidant in an amount 1.2 weight to 7 weight percent of the composition, and (d) a metal-containing detergent in an amount to deliver 0.2 weight percent sulfated ash up to 1.5 weight percent sulfated ash to the composition, (e) an ashless polyolefin dispersant in an amount 0.8 weight percent to 8 weight percent of the composition, and (f) a polymeric viscosity modifier, dispersant viscosity modifier, or mixtures thereof in an amount 0.1 weight percent to 4.5 weight percent of the composition. 
     
     
         2 . The method of  claim 1 , wherein the internal combustion engine is operated at an effective compression ratio of at least 15:1. 
     
     
         3 . The method of  claim 1 , wherein the internal combustion engine is operated under a load with a brake mean effective pressure (BMEP) of greater than or equal to 18 bars. 
     
     
         4 . The method of  claim 1 , wherein the gasoline has an octane rating of at least 95 by the (R+M)/2 method. 
     
     
         5 . The method of  claim 1 , wherein the internal combustion engine is spark ignited. 
     
     
         6 . The method of  claim 1 , wherein the internal combustion engine is compression ignited. 
     
     
         7 . The method of claim[[s]] 1 to 6, wherein the internal combustion engine is a gasoline direct injection (GDI) engine. 
     
     
         8 . The method of  claim 1 , wherein the internal combustion engine is equipped with a turbocharger, a super charger, an air booster, or combinations thereof. 
     
     
         9 . The method of  claim 1 , wherein the internal combustion engine is operated with variable valve timing. 
     
     
         10 . The method of  claim 1 , wherein the internal combustion engine is operated with an air-fuel equivalence ratio (X) of less than 1.2. 
     
     
         11 . The method of  claim 1 , wherein the internal combustion engine is operated at speeds less than or equal to 3000 rpm. 
     
     
         12 . The method of any of  claim 1 , wherein the anti-wear additive comprises a phosphorus-containing additive, a phosphorus-free additive, or combinations thereof. 
     
     
         13 . The method of  claim 12 , wherein the phosphorus-containing additive is selected from metal dialkyldithiophosphates, amino phosphate salts, hydrocarbyl phosphites, hydrocarbyl phosphines, hydrocarbyl phosphonates, and combinations thereof. 
     
     
         14 . The method of  claim 12 , wherein the phosphorus-free anti-wear additive is selected from hydrocarbyl esters, amides, or imides of hydroxy-substituted carboxylic acid acids and mixtures thereof. 
     
     
         15 . The method of  claim 1 , wherein the metal detergent is a selected from a neutral alkaline earth metal detergent, an overbased alkaline earth metal detergent, and combinations thereof. 
     
     
         16 . The method of  claim 15 , wherein the alkaline earth metal detergent comprises calcium detergents, magnesium detergent, and mixtures thereof. 
     
     
         17 . The method of  claim 1 , wherein the oil of lubricating viscosity has a kinematic viscosity of at least 4.2 m 2 /s at 100 ° C. 
     
     
         18 . The method of  claim 1 , wherein the lubricant composition has a viscosity grade according to SAE J300 of XW-YY, wherein X is 0, 5, 10 or 15, and YY is 8, 12, 16, 20, 30, or 40. 
     
     
         19 . A method of operating an internal combustion engine, comprising supplying to a sump-lubricated, high efficiency, gasoline-fueled internal combustion engine a lubricating composition comprising (a) an oil of lubricating viscosity, (b) an anti-wear agent in an amount 0.15 weight percent to 6 weight percent of the composition, (c) an ashless antioxidant in an amount 1.2 weight to 7 weight percent of the composition, and (d) a metal-containing detergent in an amount to deliver 0.2 weight percent sulfated ash up to 1.5 weight percent sulfated ash to the composition, (e) an ashless polyolefin dispersant in an amount 0.8 weight percent to 8 weight percent of the composition, and (f) a polymeric viscosity modifier, dispersant viscosity modifier, or mixtures thereof in an amount 0.1 weight percent to 4.5 weight percent of the composition. 
     
     
         20 . A method of reducing friction power loss in a sump-lubricated, high efficiency, gasoline-fueled internal combustion engine comprising operating said engine and lubricating said engine with a lubricant composition comprising (a) an oil of lubricating viscosity, (b) an anti-wear agent in an amount 0.15 weight percent to 6 weight percent of the composition, (c) an ashless antioxidant in an amount 1.2 weight to 7 weight percent of the composition, and (d) a metal-containing detergent in an amount to deliver 0.2 weight percent sulfated ash up to 1.5 weight percent sulfated ash to the composition, (e) an ashless polyolefin dispersant in an amount 0.8 weight percent to 8 weight percent of the composition, and (f) a polymeric viscosity modifier, dispersant viscosity modifier, or mixtures thereof in an amount 0.1 weight percent to 4.5 weight percent of the composition.