Lubricating oil composition for internal combustion engines

Abstract

A lubricating oil composition for internal combustion engines containing a specific base oil, monoglyceride with a specific structure and ethylene oxide adduct with a specific structure in specific quantities and/or ratios. The lubricating oil composition of the present invention, as well as providing outstanding wear resistance and fuel economy, causes condensed water etc. from water vapour produced as a result of fuel combustion to be dispersed in the oil, so preventing corrosion or rusting of the engine.

1 . A lubricating oil composition for internal combustion engines comprising:
 (A) at least one base oil selected from the group consisting of base oils of Groups 2, 3 and 4 in the API (American Petroleum Institute) base oil categories with a kinematic viscosity of from 3 to 12 mm 2 /s at 100° C. and a viscosity index of from 100 to 180,   (B) a monoglyceride with a hydrocarbon group having from 8 to 22 carbon atoms (a glycerine fatty acid ester with the fatty acid ester bonded to one of the three hydroxyl groups of the glycerine), wherein the monoglyceride has a hydroxyl value of from 150 to 300 mgKOH/g, and wherein the monoglyceride is present at a level of from 0.3 to 2.0 mass % based on the total mass of the composition, and   (C) at least one ethylene oxide adduct selected from the group consisting of monoalkyl and monoalkenyl amine ethylene oxide adducts shown by Formula (1) below,   Formula (1):   
       
         
           
           
               
               
           
         
         wherein R is a C 14 -C 22  hydrocarbon group, n and m are independently either 1 or 2, and 
         wherein the ethylene oxide adduct is present at a level of from 0.4 to 1.5 mass % based on the total mass of the composition. 
       
     
     
         2 . The lubricating oil composition for internal combustion engines according to  claim 1  wherein the mass ratio of the aforesaid monoglyceride (B) and aforesaid ethylene oxide adduct (C) (mass % of monoglyceride B/mass % of ethylene oxide adduct C) is in the range of from 0.5 to 2.7. 
     
     
         3 . A lubricating oil composition for internal combustion engines comprising:
 (A) at least one base oil selected from the group consisting of base oils of Groups 2, 3 and 4 in the API (American Petroleum Institute) base oil categories with a kinematic viscosity of from 3 to 12 mm 2 /s at 100° C. and a viscosity index of from 100 to 180,   (B) a monoglyceride with a hydrocarbon group having from 8 to 22 carbon atoms (a glycerine fatty acid ester with the fatty acid ester bonded to one of the three hydroxyl groups of the glycerine), wherein the monoglyceride has a hydroxyl value of from 150 to 300 mgKOH/g, and   (C) at least one ethylene oxide adduct selected from the group consisting of monoalkyl and monoalkenyl amine ethylene oxide adducts having Formula (1) below,   Formula (1):   
       
         
           
           
               
               
           
         
         wherein R is a C 14 -C 22  hydrocarbon group, n and m are independently either 1 or 2, and 
         wherein the mass ratio of the aforesaid monoglyceride (B) and aforesaid ethylene oxide adduct (C) (mass % of monoglyceride B/mass % of ethylene oxide adduct C) is in the range from 0.5 to 2.7. 
       
     
     
         4 . The lubricating oil composition for internal combustion engines according to  claim 3  wherein the aforesaid monoglyceride is present at a level of from 0.3 to 2.0 mass % based on the total mass of the composition, and wherein the ethylene oxide adduct is present at a level of from 0.4 to 1.5 mass % based on the total mass of the composition. 
     
     
         5 . The lubricating oil composition for internal combustion engines according to  claim 1  wherein the ethylene oxide adduct (C) is a diethanolamine. 
     
     
         6 . The lubricating oil composition for internal combustion engines according to  claim 1  wherein the ethylene oxide adduct (C) is oleyl diethanolamine. 
     
     
         7 . The lubricating oil composition for internal combustion engines according to  claim 1  wherein the monoglyceride (B) is glycerine monooleate. 
     
     
         8 . The lubricating oil composition for internal combustion engines according to  claim 1  wherein the composition has a kinematic viscosity at 100° C. in the range from 5.6 to 15 mm 2 /s. 
     
     
         9 . (canceled) 
     
     
         10 . The lubricating oil composition for internal combustion engines according to  claim 3  wherein the ethylene oxide adduct (C) is a diethanolamine. 
     
     
         11 . The lubricating oil composition for internal combustion engines according to  claim 3  wherein the ethylene oxide adduct (C) is oleyl diethanolamine. 
     
     
         12 . The lubricating oil composition for internal combustion engines according to  claim 3  wherein the monoglyceride (B) is glycerine monooleate. 
     
     
         13 . The lubricating oil composition for internal combustion engines according to  claim 3  wherein the composition has a kinematic viscosity at 100° C. in the range from 5.6 to 15 mm 2 /s. 
     
     
         14 . A method comprising lubricating an internal combustion engine with a lubricating oil composition that comprises:
 (A) at least one base oil selected from the group consisting of base oils of Groups 2, 3 and 4 in the API (American Petroleum Institute) base oil categories with a kinematic viscosity of from 3 to 12 mm 2 /s at 100° C. and a viscosity index of from 100 to 180,   (B) a monoglyceride with a hydrocarbon group having from 8 to 22 carbon atoms (a glycerine fatty acid ester with the fatty acid ester bonded to one of the three hydroxyl groups of the glycerine), wherein the monoglyceride has a hydroxyl value of from 150 to 300 mgKOH/g, and wherein the monoglyceride is present at a level of from 0.3 to 2.0 mass % based on the total mass of the composition, and   (C) at least one ethylene oxide adduct selected from the group consisting of monoalkyl and monoalkenyl amine ethylene oxide adducts shown by Formula (1) below,   Formula (1):   
       
         
           
           
               
               
           
         
         wherein R is a C 14 -C 22  hydrocarbon group, n and m are independently either 1 or 2, 
         wherein the ethylene oxide adduct is present at a level of from 0.4 to 1.5 mass % based on the total mass of the composition, and 
         wherein the internal combustion engine uses a fuel with H/C ratios of from 1.93 to 4, is fitted with idle-stop equipment, or uses a fuel incorporating a biofuel or a biodiesel. 
       
     
     
         15 . The method according to  claim 14  wherein the mass ratio of the aforesaid monoglyceride (B) and aforesaid ethylene oxide adduct (C) (mass % of monoglyceride B/mass % of ethylene oxide adduct C) is in the range of from 0.5 to 2.7. 
     
     
         16 . The method according to  claim 14  wherein the ethylene oxide adduct (C) is a diethanolamine. 
     
     
         17 . The method according to  claim 14  wherein the ethylene oxide adduct (C) is oleyl diethanolamine. 
     
     
         18 . The method according to  claim 14  wherein the monoglyceride (B) is glycerine monooleate. 
     
     
         19 . The method according to  claim 14  wherein the composition has a kinematic viscosity at 100° C. in the range from 5.6 to 15 mm 2 /s.