Trunk piston engine lubricating oil compositions

Abstract

A trunk piston engine lubricating oil composition is disclosed comprising (a) a major amount of a base stock containing at least 90% by weight saturated hydrocarbons; and (b) a base stock selected from the group consisting of (i) an ester base stock wherein the ester base stock is present in an amount greater than 10% by weight and no greater than about 45% by weight, based on the total weight of the lubricating oil composition, and (ii) an alkylated aromatic base stock.

1 . A trunk piston engine lubricating oil composition comprising (a) a major amount of a base stock containing at least 90% by weight saturated hydrocarbons; and (b) a base stock selected from the group consisting of (i) an ester base stock wherein the ester base stock is present in an amount greater than 10% by weight and no greater than about 45% by weight, based on the total weight of the lubricating oil composition, and (ii) an alkylated aromatic base stock. 
     
     
         2 . The trunk piston engine lubricating oil composition of  claim 1 , wherein the base stock comprising at least 90% by weight saturated hydrocarbons comprises at least one of a Group II base stock, a Group III base stock or a base stock derived from a Fischer-Tropsch synthesized, waxy, paraffinic hydrocarbon material. 
     
     
         3 . The trunk piston engine lubricating oil composition of  claim 1 , wherein the base stock comprising at least 90% by weight saturated hydrocarbons comprises at least one Group II base stock. 
     
     
         4 . The trunk piston engine lubricating oil composition of  claim 1 , which is substantially free of a Group I base stock. 
     
     
         5 . The trunk piston engine lubricating oil composition of  claim 1 , wherein the base stock (b) is an ester base stock. 
     
     
         6 . The trunk piston engine lubricating oil composition of  claim 1 , wherein the base stock (b) is an ester base stock, wherein the ester base stock has a kinematic viscosity of about 2 to about 10 cSt at 100° C. 
     
     
         7 . The trunk piston engine lubricating oil composition of  claim 5 , wherein the ester base stock is a polyol ester base stock. 
     
     
         8 . The trunk piston engine lubricating oil composition of  claim 1 , wherein the base stock (b) is an alkylated aromatic base stock. 
     
     
         9 . The trunk piston engine lubricating oil composition of  claim 8 , wherein the alkylated aromatic base stock is an alkylated fused and/or polyfused aromatic base stock. 
     
     
         10 . The trunk piston engine lubricating oil composition of  claim 8 , wherein the alkylated aromatic base stock is an alkylated naphthalene. 
     
     
         11 . The trunk piston engine lubricating oil composition of  claim 1 , further comprising one or more trunk piston engine lubricating oil composition additives selected from the group consisting of an antioxidant, anti-wear agent, detergent, rust inhibitor, dehazing agent, demulsifying agent, metal deactivating agent, friction modifier, pour point depressant, antifoaming agent, co-solvent, package compatibiliser, corrosion-inhibitor, ashless dispersant, dye, extreme pressure agent and mixtures thereof. 
     
     
         12 . A method for improving heavy fuel oil compatibility of a trunk piston engine lubricating oil composition comprising a major amount of a base stock containing at least 90% by weight saturated hydrocarbons, the method comprising adding to the trunk piston engine lubricating oil composition a base stock selected from the group consisting of (i) an ester base stock wherein the ester base stock is present in an amount greater than 10% by weight and no greater than about 45% by weight, based on the total weight of the lubricating oil composition, and (ii) an alkylated aromatic base stock. 
     
     
         13 . The method of  claim 12 , wherein the base stock comprising at least 90% by weight saturated hydrocarbons comprises at least one of a Group II base stock, a Group III base stock or a base stock derived from a Fischer-Tropsch synthesized, waxy, paraffinic hydrocarbon material. 
     
     
         14 . The method of  claim 12 , wherein the base stock comprising at least 90% by weight saturated hydrocarbons comprises at least one Group II base stock. 
     
     
         15 . The method of  claim 12 , wherein the base stock added to the trunk piston engine lubricating oil composition is an ester base stock. 
     
     
         16 . The method of  claim 15 , wherein the ester base stock is a polyol ester base stock. 
     
     
         17 . The method of  claim 12 , wherein the base stock added to the trunk piston engine lubricating oil composition is an alkylated aromatic base stock. 
     
     
         18 . The method of  claim 17 , wherein the alkylated aromatic base stock is an alkylated naphthalene. 
     
     
         19 . The method of  claim 12 , wherein the trunk piston engine lubricating oil composition further comprises one or more trunk piston engine lubricating oil composition additives selected from the group consisting of an antioxidant, anti-wear agent, detergent, rust inhibitor, dehazing agent, demulsifying agent, metal deactivating agent, friction modifier, pour point depressant, antifoaming agent, co-solvent, package compatibiliser, corrosion-inhibitor, ashless dispersant, dye, extreme pressure agent and mixtures thereof. 
     
     
         20 . A method for operating a trunk piston engine, the method comprising lubricating the trunk piston engine with a trunk piston engine lubricating oil composition comprising (a) a major amount of a base stock containing at least 90% by weight saturated hydrocarbons; and (b) a base stock selected from the group consisting of (i) an ester base stock wherein the ester base stock is present in an amount greater than 10% by weight and no greater than about 45% by weight, based on the total weight of the lubricating oil composition, and (ii) an alkylated aromatic base stock.