Lubricating oil compositions with oxidative stability in diesel engines using biodiesel fuel

Abstract

A method for improving oxidative stability of a lubricating oil in a diesel engine, in which biodiesel fuel is used with diesel fuel in the diesel engine, by using as the lubricating oil a formulated oil. The formulated oil has a composition including at least one Group V lubricating oil base stock. The at least one Group V lubricating oil base stock is present in an amount from 1 to 75 weight percent, based on the total weight of the lubricating oil. Oxidative stability is improved in a diesel engine lubricated with the lubricating oil, as compared to oxidative stability achieved in a diesel engine lubricated with a lubricating oil not having the at least one Group V lubricating oil base stock, as determined by a CEC L-109-16 Bio-Diesel Oxidation Bench test. The lubricating oils are useful as passenger vehicle engine oil (PVEO) products or commercial vehicle engine oil (CVEO) products.

1 . A method for improving oxidative stability of a lubricating oil in a diesel engine, wherein biodiesel fuel is used with diesel fuel in the diesel engine, by using as the lubricating oil a formulated oil, said formulated oil having a composition comprising at least one Group V lubricating oil base stock; wherein the at least one Group V lubricating oil base stock is present in an amount from 1 to 75 weight percent, based on the total weight of the lubricating oil; and wherein oxidative stability is improved in a diesel engine lubricated with the lubricating oil, as compared to oxidative stability achieved in a diesel engine lubricated with a lubricating oil not having the at least one Group V lubricating oil base stock, as determined by a CEC L-109-16 Bio-Diesel Oxidation Bench test. 
     
     
         2 . The method of  claim 1  wherein, in a CEC L-109-16 Bio-Diesel Oxidation Bench test, the time for a relative kinematic viscosity at 100° C. (KV100) increase of 100% of said lubricating oil, is greater than the time for a relative kinematic viscosity at 100° C. (KV100) increase of 100% of a lubricating oil not having the at least one Group V lubricating oil base stock. 
     
     
         3 . The method of  claim 2  wherein, in a CEC L-109-16 Bio-Diesel Oxidation Bench test, the time for a relative kinematic viscosity at 100° C. (KV100) increase of 100% of said lubricating oil is from 260 to 500 hours. 
     
     
         4 . The method of  claim 2  wherein, in a CEC L-109-16 Bio-Diesel Oxidation Bench test, the time for a relative kinematic viscosity at 100° C. (KV100) increase of 100% of said lubricating oil, is greater than at least 5% of the time for a relative kinematic viscosity at 100° C. (KV100) increase of 100% of a lubricating oil not having the at least one Group V lubricating oil base stock. 
     
     
         5 . The method of  claim 1  wherein the at least one Group V lubricating oil base stock comprises an ester base stock, an alkylated aromatic base stock, an amide base stock, or mixtures thereof. 
     
     
         6 . The method of  claim 1  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. 
     
     
         7 . 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. 
     
     
         8 . 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. 
     
     
         9 . 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. 
     
     
         10 . 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. 
     
     
         11 . The method of  claim 5  wherein the ester base stock comprises a monoester, diester, glyceryl ester, polyether ester, pentaerythritol ester, trimethylol propane ester, glycerol ester, or phthalate ester; the alkylated aromatic base stock comprises an alkylated naphthalene, alkylated anisole, alkylated diphenyl oxide, or alkylated diphenyl sulfide; and the amide base stock comprises an alkylated amide. 
     
     
         12 . The method of  claim 5  wherein the ester base stock comprises a trimethylol propane ester base stock, the alkylated aromatic base stock comprises an alkylated naphthalene base stock, and the amide base stock comprises an alkylated amide base stock. 
     
     
         13 . The method of  claim 1  wherein the at least one Group V lubricating oil base stock comprises is present in an amount from 1 to 70 weight percent, based on the total weight of the lubricating oil. 
     
     
         14 . The method of  claim 1  wherein the at least one Group V lubricating oil base stock comprises is present in an amount from 5 to 60 weight percent, based on the total weight of the lubricating oil. 
     
     
         15 . The method of  claim 1  wherein the lubricating oil further comprises a Group I, Group II, Group III, or Group IV base oil. 
     
     
         16 . The method of  claim 1  wherein the formulated oil further comprises one or more of an antioxidant, viscosity modifier, dispersant, detergent, pour point depressant, corrosion inhibitor, metal deactivator, seal compatibility additive, anti-foam agent, inhibitor, and anti-rust additive. 
     
     
         17 . The method of  claim 1  wherein the lubricating oil is a passenger vehicle engine oil (PVEO) or a commercial vehicle engine oil (CVEO). 
     
     
         18 . A lubricating oil having a composition comprising at least one Group V lubricating oil base stock; wherein the at least one Group V lubricating oil base stock is present in an amount from 1 to 75 weight percent, based on the total weight of the lubricating oil; and wherein oxidative stability is improved in a diesel engine, wherein biodiesel fuel is used with diesel fuel in the diesel engine, lubricated with the lubricating oil, as compared to oxidative stability achieved in a diesel engine lubricated with a lubricating oil not having the at least one Group V lubricating oil base stock, as determined by a CEC L-109-16 Bio-Diesel Oxidation Bench test. 
     
     
         19 . The lubricating oil of  claim 18  wherein, in a CEC L-109-16 Bio-Diesel Oxidation Bench test, the time for a relative kinematic viscosity at 100° C. (KV100) increase of 100% of said lubricating oil, is greater than the time for a relative kinematic viscosity at 100° C. (KV100) increase of 100% of a lubricating oil not having the at least one Group V lubricating oil base stock. 
     
     
         20 . The lubricating oil of  claim 19  wherein, in a CEC L-109-16 Bio-Diesel Oxidation Bench test, the time for a relative kinematic viscosity at 100° C. (KV100) increase of 100% of said lubricating oil is from 260 to 500 hours. 
     
     
         21 . The lubricating oil of  claim 19  wherein, in a CEC L-109-16 Bio-Diesel Oxidation Bench test, the time for a relative kinematic viscosity at 100° C. (KV100) increase of 100% of said lubricating oil, is greater than at least 5% of the time for a relative kinematic viscosity at 100° C. (KV100) increase of 100% of a lubricating oil not having the at least one Group V lubricating oil base stock. 
     
     
         22 . The lubricating oil of  claim 18  wherein the at least one Group V lubricating oil base stock comprises an ester base stock, an alkylated aromatic base stock, an amide base stock, or mixtures thereof. 
     
     
         23 . The lubricating oil of  claim 18  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. 
     
     
         24 . The lubricating oil of  claim 18  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. 
     
     
         25 . The lubricating oil of  claim 18  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. 
     
     
         26 . The lubricating oil of  claim 18  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. 
     
     
         27 . The lubricating oil of  claim 18  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. 
     
     
         28 . The lubricating oil of  claim 18  wherein the ester base stock comprises a monoester, diester, glyceryl ester, polyether ester, pentaerythritol ester, trimethylol propane ester, glycerol ester, or phthalate ester; the alkylated aromatic base stock comprises an alkylated naphthalene, alkylated anisole, alkylated diphenyl oxide, or alkylated diphenyl sulfide; and the amide base stock comprises an alkylated amide. 
     
     
         29 . The lubricating oil of  claim 22  wherein the ester base stock comprises a trimethylol propane ester base stock, the alkylated aromatic base stock comprises an alkylated naphthalene base stock, and the amide base stock comprises an alkylated amide base stock. 
     
     
         30 . The lubricating oil of  claim 18  wherein the at least one Group V lubricating oil base stock comprises is present in an amount from 1 to 70 weight percent, based on the total weight of the lubricating oil. 
     
     
         31 . The lubricating oil of  claim 18  wherein the at least one Group V lubricating oil base stock comprises is present in an amount from 5 to 60 weight percent, based on the total weight of the lubricating oil. 
     
     
         32 . The lubricating oil of  claim 18  wherein the lubricating oil further comprises a Group I, Group II, Group III, or Group IV base oil. 
     
     
         33 . The lubricating oil of  claim 18  wherein the formulated oil further comprises one or more of an antioxidant, viscosity modifier, dispersant, detergent, pour point depressant, corrosion inhibitor, metal deactivator, seal compatibility additive, anti-foam agent, inhibitor, and anti-rust additive. 
     
     
         34 . The lubricating oil of  claim 18  wherein the lubricating oil is a passenger vehicle engine oil (PVEO) or a commercial vehicle engine oil (CVEO).