Lubricating oil composition

Abstract

A lubricating oil composition provides improved anti-shudder performance by lubricating an automatic transmission or continuously variable transmission. The lubricating oil composition includes (a) one or more ashless dispersants; and (b) at least one acidic phosphorus compound. When the at least one acidic phosphorus compound is composed only of phosphoric acid, the lubricating oil composition additionally contains one or more neutral phosphorus compounds. The neutralization ratio of the (a) one or more ashless dispersants/the (b) at least one acidic phosphorus compound is 60 to 100%. The lubricating oil composition further includes at least one friction modifier.

1 . A lubricating oil composition comprising:
 a major amount of an oil of lubricating viscosity having a kinematic viscosity at 100° C. of 2 to 12 mm 2 /s;   (a) one or more ashless dispersants;   (b) at least one acidic phosphorus compound (B1) selected from the group consisting of: phosphoric acid, a phosphorus compound of the following structures, and a combination thereof:   
       
         
           
           
               
               
           
         
         
           wherein R 1 -R 3  are independently a C1-C20 hydrocarbyl group that may optionally contain an ether or thioether moiety; 
           wherein R 4  is a hydrogen atom or a C1-C20 hydrocarbyl group that may optionally contain an ether or thioether moiety 
           wherein when the at least one acidic phosphorus compound (B1) is composed only of phosphoric acid, the lubricating oil composition additionally contains one or more neutral phosphorus compound (B2) selected from the group consisting of: phosphate esters, phosphite esters, hydrogen phosphite ester, thiosphosphate esters, and amine salts thereof; 
           wherein the neutralization ratio of the (a) one or more ashless dispersants/the (b) at least one acidic phosphorus compound (B1) is 60 to 100%; 
         
         (c) at least one friction modifier (C1), wherein the friction modifier is a reaction product of alkenyl-substituted succinic anhydride with a polyamine; and 
         (d) at least one friction modifier (C2) selected from the oiliness agent group consisting of diols, ethoxylated amines, fatty acid esters, sulfurized fatty acid esters, amides, and alcohols. 
       
     
     
         2 . The lubricating oil composition of  claim 1  including phosphorus in an amount of 0.01 wt. % to 0.20 wt. %, based on the total weight of the lubricating oil composition. 
     
     
         3 . The lubricating oil composition of  claim 1  including sulfated ash in an amount less than 0.3 wt. %, based on the total weight of the lubricating oil composition. 
     
     
         4 . The lubricating oil composition of  claim 1 , wherein the neutralization ratio is 75 to 100%. 
     
     
         5 . The lubricating oil composition of  claim 1 , wherein the at least one acidic phosphorus compound (B1) includes a mixture of mono/dialkyl phosphite ester containing thioether alkyl groups. 
     
     
         6 . The lubricating oil composition of  claim 5 , wherein the at least one acidic phosphorus compound (B1) further includes phosphoric acid. 
     
     
         7 . The lubricating oil composition of  claim 1  including diphenyl hydrogen phosphite, di-lauryl hydrogen phosphite, and an alkyl amine salt of an alkyl phosphate ester as the one or more neutral phosphorus compound (B2). 
     
     
         8 . The lubricating oil composition of  claim 1 , wherein the at least one acidic phosphorus compound (B1) includes only phosphoric acid, and the one or more neutral phosphorus compound (B2) includes diphenyl hydrogen phosphite, di-lauryl hydrogen phosphite, and an alkyl amine salt of an alkyl phosphate ester. 
     
     
         9 . The lubricating oil composition of  claim 1 , wherein the one or more ashless dispersants includes polyisobutenyl succinimide; the at least one acidic phosphorus compound (B1) includes at least one of: phosphoric acid and a mixture of mono/dialkyl phosphite ester containing thioether alkyl groups; the one or more neutral phosphorus compound (B2), if present, includes diphenyl hydrogen phosphite, di-lauryl hydrogen phosphite and/or an alkyl amine salt of an alkyl phosphate ester; the friction modifier (C1) includes a reaction product of C20 alkenyl-substituted succinic anhydride with diethylene triamine; and the at least one friction modifier (C2) includes an ethoxylated monoalkyl amine and/or a mixture of C16 and C18 diol. 
     
     
         10 . The lubricating oil composition of  claim 9 , wherein the oil of lubricating viscosity includes a mixture of a Group II base oil and a Group III base oil; and the lubricating oil composition further includes at least one of a detergent, antioxidant, metal deactivator, foam inhibitor, seal swell agent, and viscosity modifier. 
     
     
         11 . The lubricating oil composition of  claim 1 , wherein the initial pH (i-pH) as determined by ASTM D664 of a mixture of A and B1 is 4 to 10. 
     
     
         12 . The lubricating oil composition of  claim 1 , wherein the initial pH (i-pH) as determined by ASTM D664 of a mixture of A and B1 is 4.5 to 9.5. 
     
     
         13 . A method of improving anti-shudder performance, comprising:
 lubricating a transmission with a lubricating oil composition, the lubricating oil composition including:   a major amount of an oil of lubricating viscosity having a kinematic viscosity at 100° C. of 2 to 12 mm 2 /s;   (a) one or more ashless dispersants;   (b) at least one acidic phosphorus compound (B1) selected from the group consisting of: phosphoric acid, a phosphorus compound of the following structures, and a combination thereof:   
       
         
           
           
               
               
           
         
         
           wherein R 1 -R 3  are independently a C1-C20 hydrocarbyl group that may optionally contain an ether or thioether moiety; 
           wherein R 4  is a hydrogen atom or a C1-C20 hydrocarbyl group that may optionally contain an ether or thioether moiety 
           wherein when the at least one acidic phosphorus compound (B1) is composed only of phosphoric acid, the lubricating oil composition additionally contains one or more neutral phosphorus compound (B2) selected from the group consisting of: phosphate esters, phosphite esters, hydrogen phosphite esters, thiosphosphate esters, and amine salts thereof; 
           wherein the neutralization ratio of the (a) one or more ashless dispersants/the (b) at least one acidic phosphorus compound (B1) is 60 to 100%; 
         
         (c) at least one friction modifier (C1), wherein the friction modifier is a reaction product of alkenyl-substituted succinic anhydride with a polyamine; and 
         (d) at least one friction modifier (C2) selected from the oiliness agent group consisting of diols, ethoxylated amines, fatty acid esters, sulfurized fatty acid esters, amides and alcohols. 
       
     
     
         14 . The method of  claim 13 , wherein the lubricating oil composition includes phosphorus in an amount of 0.01 wt. % to 0.20 wt. %, based on the total weight of the lubricating oil composition. 
     
     
         15 . The method of  claim 13 , wherein the lubricating oil composition includes sulfated ash in an amount of less than 0.3 wt. %, based on the total weight of the lubricating oil composition. 
     
     
         16 . The method of  claim 13 , wherein the neutralization ratio of the lubricating oil composition is 75 to 100%. 
     
     
         17 . The method of  claim 13 , wherein the at least one acidic phosphorus compound (B1) includes at least one of phosphoric acid and a mixture of mono/dialkyl phosphite ester containing thioether alkyl groups; and the one or more neutral phosphorus compound (B2) includes at least one of diphenyl hydrogen phosphite, di-lauryl hydrogen phosphite, and an alkyl amine salt of an alkyl phosphate ester. 
     
     
         18 . The method of  claim 13 , wherein the transmission is an automatic transmission or continuously variable transmission. 
     
     
         19 . The method of  claim 18 , wherein the transmission includes a wet clutch system. 
     
     
         20 . The method of  claim 19 , wherein the friction material used in the wet clutch system is a paper material that contains cellulose and/or aramid fibers. 
     
     
         21 . The method of  claim 13 , wherein the one or more ashless dispersants includes polyisobutenyl succinimide; the at least one acidic phosphorus compound (B1) includes at least one of: phosphoric acid and a mixture of mono/dialkyl phosphite ester containing thioether alkyl groups; the one or more neutral phosphorus compound (B2), if present, includes diphenyl hydrogen phosphite and/or an alkyl amine salt of an alkyl phosphate ester; the friction modifier (C1) includes a reaction product of C20 alkenyl-substituted succinic anhydride with diethylene triamine; and the at least one friction modifier (C2) includes at least one of an ethoxylated monoalkyl amine and a mixture of C16 and C18 diol. 
     
     
         22 . The method of  claim 13 , wherein the base oil of the lubricating oil composition includes a mixture of a Group II base oil and a Group III base oil; and the lubricating oil composition further includes at least one of a detergent, antioxidant, metal deactivator, foam inhibitor, seal swell agent, and viscosity modifier.