Additives and lubricant formulations for improved antioxidant properties

A vehicle having a crankcase and containing a lubricant in the crankcase for lubricating the vehicle, the lubricant comprising an oil of lubricating viscosity, an organomolybdenum friction modifier, an antioxidant compound, and an amount of at least one hydrocarbon soluble titanium compound effective to provide an oxidation stability rating of the lubricant of less than about 39 milligrams according to a TEOST MHT-4 test, wherein the lubricant is devoid of titanium compounds that contain phosphorus atoms and titanium compounds that contain sulfur and phosphorus atoms, and wherein the lubricant is substantially devoid of phenolic antioxidant compounds and wherein the amount of hydrocarbon soluble titanium compound provides from about 1 to about 1500 parts per million titanium in the lubricant, wherein the hydrocarbon soluble titanium compound comprises the reaction product of a titanium alkoxide and a non-linear carboxylic acid.

A fully formulated crankcase lubricant composition for an engine comprising a base oil component of lubricating viscosity, an antioxidant compound, and an amount of hydrocarbon soluble titanium-containing agent effective to provide an oxidation stability rating of the lubricant composition of less than about 39 milligrams according to a TEOST MHT-4 test, wherein the lubricant composition is devoid of phenolic antioxidant compounds and is devoid of titanium-containing agents that contain phosphorus atoms and wherein the amount of hydrocarbon soluble titanium-containing agent provides from about 1 to about 1500 parts per million titanium in the lubricant composition, wherein the hydrocarbon soluble titanium compound comprises the reaction product of a titanium alkoxide and a non-linear carboxylic acid.

A method of reducing oxidation of engine lubricant compositions during operation of an engine containing the lubricant composition in the substantial absence of phenolic antioxidant compounds, comprising contacting a crankcase of the engine with a lubricant composition comprising a base oil of lubricating viscosity, an antioxidant compound, and an amount of a hydrocarbon soluble titanium compound effective to provide an oxidation stability rating of the lubricant composition of less than about 39 milligrams according to a TEOST MHT-4 test, wherein the lubricant composition is devoid of titanium compounds that contain phosphorus atoms and wherein the amount of hydrocarbon soluble titanium compound provides from about 1 to about 1500 parts per million titanium in the lubricant composition, wherein the hydrocarbon soluble titanium compound comprises the reaction product of a titanium alkoxide and a non-linear carboxylic acid.

A method of lubricating moving parts of an engine crankcase with a lubricating oil exhibiting an oxidation stability rating of less than about 39 milligrams according to a TEOST MHT-4 test in the substantial absence of phenolic antioxidants, the method comprising using as the lubricating oil for one or more moving parts a lubricant composition containing a base oil, an organomolybdenum friction modifier, and an antioxidant additive, the antioxidant additive comprising a hydrocarbyl carrier fluid, an amount of hydrocarbon soluble titanium compound providing from about 1 to about 1500 parts per million titanium in the lubricating oil, and an antioxidant compound other than the titanium compound, wherein the lubricant composition is devoid of titanium compounds that contain phosphorus atoms, wherein the hydrocarbon soluble titanium compound comprises the reaction product of a titanium alkoxide and a non-linear carboxylic acid.