Ashless engine lubricants for high temperature applications

Abstract

An ashless lubricating oil having a lubricating oil base stock as a major component, and a mixture of (i) at least one ashless antiwear additive, (ii) at least one ashless detergent, and (iii) at least one aminic antioxidant, as minor components. The lubricating oil base stock is a branched polyol ester. The lubricating oil base stock is present in an amount from about 30 to about 99.8 mass percent, based on the total mass of the ashless lubricating oil. A method for improving oxidative stability and high temperature stability of a lubricating oil in an engine or other mechanical component lubricated with the lubricating oil by using the ashless lubricating oil. The ashless lubricating oil is useful as a passenger vehicle engine oil (PVEO).

1 . A method for improving oxidative stability of a lubricating oil in an engine or other mechanical component lubricated with the lubricating oil by using as the lubricating oil an ashless formulated oil, said ashless formulated oil having a composition comprising a lubricating oil base stock as a major component; and a mixture of (i) at least one ashless antiwear additive, (ii) at least one ashless detergent, and (iii) at least one aminic antioxidant, as minor components; wherein the lubricating oil base stock comprises at least one branched polyol ester, which is obtained by reacting one or more polyhydric alcohols with one or more branched mono-carboxylic acids containing at least 4 carbon atoms, and wherein the lubricating oil base stock is present in an amount from 30 to 99.8 mass percent, based on the total mass of the lubricating oil. 
     
     
         2 . The method of  claim 1  wherein oxidative stability is improved, as compared to oxidative stability achieved using a lubricating oil other than the ashless formulated oil. 
     
     
         3 . The method of  claim 1  wherein the one or more polyhydric alcohols are selected from the group consisting of trimethylol propane, pentaerythritol, neopentyl glycol, trimethylol ethane, 2-methyl-2-propyl-1,3-propanediol, and dipentaerythritol. 
     
     
         4 . The method of  claim 1  wherein the one or more branched mono-carboxylic acids containing at least 4 carbon atoms are selected from the group consisting of 3,5,5-trimethyl hexanoic acid (TMH), 2,2-dimethyl propionic acid (neopentanoic acid), neoheptanoic acid, neooctanoic acid, neononanoic acid, iso-hexanoic acid, neodecanoic acid, 2-ethyl hexanoic acid (2EH), isoheptanoic acid, isooctanoic acid, isononanoic acid, and isodecanoic acid. 
     
     
         5 . The method of  claim 1  wherein the at least one branched polyol ester is selected from the group consisting of trimethylol propane ester of 3,5,5-trimethyl hexanoic acid (TMH), trimethylol propane ester of 2,2-dimethyl propionic acid (neopentanoic acid), trimethylol propane ester of neoheptanoic acid, trimethylol propane ester of neooctanoic acid, trimethylol propane ester of neononanoic acid, trimethylol propane ester of iso-hexanoic acid, trimethylol propane ester of neodecanoic acid, trimethylol propane ester of 2-ethyl hexanoic acid (2EH), trimethylol propane ester of isoheptanoic acid, trimethylol propane ester of isooctanoic acid, trimethylol propane ester of isononanoic acid, and trimethylol propane ester of isodecanoic acid. 
     
     
         6 . The method of  claim 1  wherein the at least one branched polyol ester is selected from the group consisting of pentaerythritol ester of 3,5,5-trimethyl hexanoic acid (TMH), pentaerythritol ester of 2,2-dimethyl propionic acid (neopentanoic acid), pentaerythritol ester of neoheptanoic acid, pentaerythritol ester of neooctanoic acid, pentaerythritol ester of neononanoic acid, pentaerythritol ester of iso-hexanoic acid, pentaerythritol ester of neodecanoic acid, pentaerythritol ester of 2-ethyl hexanoic acid (2EH), pentaerythritol ester of isoheptanoic acid, pentaerythritol ester of isooctanoic acid, pentaerythritol ester of isononanoic acid, and pentaerythritol ester of isodecanoic acid. 
     
     
         7 . The method of  claim 1  wherein the at least one ashless antiwear additive is selected from the group consisting of an amine phosphate, a thiophosphate, a dithiophosphate, an amine salt of sulfurized phosphate, an alkylated triphenyl phosphorothionate, a sulfurized triglyceride, and mixtures thereof. 
     
     
         8 . The method of  claim 1  wherein the at least one ashless detergent is selected from the group consisting of a polyoxyethylene alkyl ether, a polyoxypropylene alkyl ether, and a polyoxybutylene alkyl ether. 
     
     
         9 . The method of  claim 1  wherein the at least one aminic antioxidant is selected from the group consisting of p,p′-dioctyldiphenylamine, octylated phenyl-alpha-naphthylamine, octylated/butylated diphenylamine, and a polymeric aminic antioxidant. 
     
     
         10 . The method of  claim 9  wherein the polymeric aminic antioxidant is the polymerization reaction product of one or more substituted or hydrocarbyl-substituted diphenyl amines, one or more unsubstituted or hydrocarbyl-substituted phenyl naphthyl amines, or a combination thereof. 
     
     
         11 . The method of  claim 1  wherein the at least one ashless antiwear additive is present in an amount from 0.01 to 1.2 mass percent, based on the total mass of the lubricating oil. 
     
     
         12 . The method of  claim 1  wherein the at least one ashless detergent is present in an amount from 0.01 to 6 mass percent, based on the total mass of the lubricating oil. 
     
     
         13 . The method of  claim 1  wherein the at least one aminic antioxidant is present in an amount from 0.01 to 15 mass percent, based on the total mass of the lubricating oil. 
     
     
         14 . The method of  claim 1  wherein the ashless formulated oil further comprises one or more of a viscosity modifier, dispersant, pour point depressant, corrosion inhibitor, metal deactivator, seal compatibility additive, anti-foam agent, inhibitor, and anti-rust additive. 
     
     
         15 . The method of  claim 1  wherein the engine or other mechanical component comprises a high energy density gasoline engine equipped with turbo chargers, or gasoline particular filters (GPFs). 
     
     
         16 . The method of  claim 1  wherein the lubricating oil is a passenger vehicle engine oil (PVEO). 
     
     
         17 . An ashless lubricating oil having a composition comprising a lubricating oil base stock as a major component; and a mixture of (i) at least one ashless antiwear additive, (ii) at least one ashless detergent, and (iii) at least one aminic antioxidant, as minor components; wherein the lubricating oil base stock comprises at least one branched polyol ester, which is obtained by reacting one or more polyhydric alcohols with one or more branched mono-carboxylic acids containing at least 4 carbon atoms; and wherein the lubricating oil base stock is present in an amount from 30 to 99.8 mass percent, based on the total mass of the ashless lubricating oil. 
     
     
         18 . The ashless lubricating oil of  claim 17  wherein, in an engine or other mechanical component lubricated with the ashless lubricating oil, oxidative stability is improved achieved using a lubricating oil other than the ashless lubricating oil. 
     
     
         19 . The ashless lubricating oil of  claim 17  wherein the one or more polyhydric alcohols are selected from the group consisting of trimethylol propane, pentaerythritol, neopentyl glycol, trimethylol ethane, 2-methyl-2-propyl-1,3-propanediol, and dipentaerythritol. 
     
     
         20 . The ashless lubricating oil of  claim 17  wherein the one or more branched mono-carboxylic acids containing at least 4 carbon atoms are selected from the group consisting of 3,5,5-trimethyl hexanoic acid (TMH), 2,2-dimethyl propionic acid (neopentanoic acid), neoheptanoic acid, neooctanoic acid, neononanoic acid, iso-hexanoic acid, neodecanoic acid, 2-ethyl hexanoic acid (2EH), isoheptanoic acid, isooctanoic acid, isononanoic acid, and isodecanoic acid. 
     
     
         21 . The ashless lubricating oil of  claim 17  wherein the at least one branched polyol ester is selected from the group consisting of trimethylol propane ester of 3,5,5-trimethyl hexanoic acid (TMH), trimethylol propane ester of 2,2-dimethyl propionic acid (neopentanoic acid), trimethylol propane ester of neoheptanoic acid, trimethylol propane ester of neooctanoic acid, trimethylol propane ester of neononanoic acid, trimethylol propane ester of iso-hexanoic acid, trimethylol propane ester of neodecanoic acid, trimethylol propane ester of 2-ethyl hexanoic acid (2EH), trimethylol propane ester of isoheptanoic acid, trimethylol propane ester of isooctanoic acid, trimethylol propane ester of isononanoic acid, and trimethylol propane ester of isodecanoic acid. 
     
     
         22 . The ashless lubricating oil of  claim 17  wherein the at least one branched polyol ester is selected from the group consisting of pentaerythritol ester of 3,5,5-trimethyl hexanoic acid (TMH), pentaerythritol ester of 2,2-dimethyl propionic acid (neopentanoic acid), pentaerythritol ester of neoheptanoic acid, pentaerythritol ester of neooctanoic acid, pentaerythritol ester of neononanoic acid, pentaerythritol ester of iso-hexanoic acid, pentaerythritol ester of neodecanoic acid, pentaerythritol ester of 2-ethyl hexanoic acid (2EH), pentaerythritol ester of isoheptanoic acid, pentaerythritol ester of isooctanoic acid, pentaerythritol ester of isononanoic acid, and pentaerythritol ester of isodecanoic acid. 
     
     
         23 . The ashless lubricating oil of  claim 17  wherein the at least one ashless antiwear additive is selected from the group consisting of an amine phosphate, a thiophosphate, a dithiophosphate, an amine salt of sulfurized phosphate, an alkylated triphenyl phosphorothionate, a sulfurized triglyceride, and mixtures thereof. 
     
     
         24 . The ashless lubricating oil of  claim 17  wherein the at least one ashless detergent is selected from the group consisting of a polyoxyethylene alkyl ether, a polyoxypropylene alkyl ether, and a polyoxybutylene alkyl ether. 
     
     
         25 . The ashless lubricating oil of  claim 17  wherein the at least one aminic antioxidant is selected from the group consisting of p,p′-dioctyldiphenylamine, octylated phenyl-alpha-naphthylamine, octylated/butylated diphenylamine, and a polymeric aminic antioxidant. 
     
     
         26 . The ashless lubricating oil of  claim 25  wherein the polymeric aminic antioxidant is the polymerization reaction product of one or more substituted or hydrocarbyl-substituted diphenyl amines, one or more unsubstituted or hydrocarbyl-substituted phenyl naphthyl amines, or a combination thereof. 
     
     
         27 . The ashless lubricating oil of  claim 17  wherein the at least one ashless antiwear additive is present in an amount from 0.01 to 1.2 mass percent, based on the total mass of the lubricating oil. 
     
     
         28 . The ashless lubricating oil of  claim 17  wherein the at least one ashless detergent is present in an amount from 0.01 to 6 mass percent, based on the total mass of the lubricating oil. 
     
     
         29 . The ashless lubricating oil of  claim 17  wherein the at least one aminic antioxidant is present in an amount from 0.01 to 15 mass percent, based on the total mass of the lubricating oil. 
     
     
         30 . The ashless lubricating oil of  claim 17  further comprising one or more of a viscosity modifier, dispersant, pour point depressant, corrosion inhibitor, metal deactivator, seal compatibility additive, anti-foam agent, inhibitor, and anti-rust additive. 
     
     
         31 . The ashless lubricating oil of  claim 17  wherein the engine or other mechanical component comprises a high energy density gasoline engine equipped with turbo chargers, or gasoline particular filters (GPFs). 
     
     
         32 . The ashless lubricating oil of  claim 17  which is a passenger vehicle engine oil (PVEO). 
     
     
         33 . A method for improving high temperature stability of a lubricating oil in an engine or other mechanical component lubricated with the lubricating oil by using as the lubricating oil an ashless formulated oil, said ashless formulated oil having a composition comprising a lubricating oil base stock as a major component; and a mixture of (i) at least one ashless antiwear additive, (ii) at least one ashless detergent, and (iii) at least one aminic antioxidant, as minor components; wherein the lubricating oil base stock comprises at least one branched polyol ester, which is obtained by reacting one or more polyhydric alcohols with one or more branched mono-carboxylic acids containing at least 4 carbon atoms, and at least one alkylated naphthalene; and wherein the lubricating oil base stock is present in an amount from 30 to 99.8 mass percent, based on the total mass of the lubricating oil.