Lubricating Composition Containing Sulphur, Phosphorus and Ashfree Antiwear Agent and Amine Containing Friction Modifier

Abstract

The invention provides a lubricating composition containing an oil of lubricating viscosity, an amine-containing friction modifier, and an ashless antiwear agent. The lubricating composition is suitable for lubricating an internal combustion engine.

1 . A lubricating composition comprising an oil of lubricating viscosity, an amine-containing friction modifier, and an ashless antiwear agent represented by Formula (1): 
     
       
         
         
             
             
         
       
     
     wherein
 Y and Y′ are independently —O—, >NH, >NR 3 , or an imide group formed by taking together both Y and Y′ groups and forming a R 1 —N< group between two >C═O groups; 
 X is independently —Z—O—Z′—, >CH 2 , >CHR 4 , >CR 4 R 5 , >C(OH)(CO 2 R 2 ), >C(CO 2 R 2 ) 2 , >CH 2 CO 2 R 2 , or >CHOR 6 ; 
 Z and Z′ are independently >CH 2 , >CHR 4 , >CR 4 R 5 , >C(OH)(CO 2 R 2 ), or >CHOR 6 ; 
 n is 0 to 10, with the proviso that when n=1, X is not >CH 2 , and when n=2, both X's are not simultaneously >CH 2 ; 
 m is 0 or 1; 
 R 1  is independently hydrogen or a hydrocarbyl group, with the proviso that when R 1  is hydrogen, m is 0, and n is more than or equal to 1; 
 R 2  is a hydrocarbyl group; 
 R 3 , R 4  and R 5  are independently hydrocarbyl groups or hydroxy-containing hydrocarbyl groups or carboxyl-containing hydrocarbyl groups; and 
 R 6  is hydrogen or a hydrocarbyl group. 
 
   
   
       2 . The lubricating composition of  claim 1 , wherein the ashless antiwear agent of Formula (1) is derived from at least one hydroxy-polycarboxylic acid. 
   
   
       3 . The lubricating composition of  claim 1  wherein the ashless antiwear agent of Formula (1) comprises a hydroxy-polycarboxylic acid di-ester, a hydroxy-polycarboxylic acid di-amide, a hydroxyl-polycarboxylic acid imide, a hydroxy-polycarboxylic acid di-imide, a hydroxy-polycarboxylic acid ester-amide, a hydroxy-polycarboxylic acid ester-imide, and a hydroxy-polycarboxylic acid imide-amide. 
   
   
       4 . The lubricating composition of  claim 1 , wherein the ashless antiwear agent represented by Formula (1) is an imide, a di-ester, or a di-amide. 
   
   
       5 . The lubricating composition of  claim 1 , wherein Y and Y′ of Formula (1) are both —O—. 
   
   
       6 . The lubricating composition of  claim 1 , wherein Formula (1) defines m as 0 or 1, n as 1 to 2, X is >CHOR 6 , and R 1 , R 2  and R 6  are independently hydrogen or hydrocarbyl groups containing 4 to 30 carbon atoms. 
   
   
       7 . The lubricating composition of  claim 1  wherein the ashless antiwear agent is derived from tartaric acid or citric acid. 
   
   
       8 . The lubricating composition of  claim 1 , wherein the ashless antiwear agent is present at 0.1 to 5 wt % of the lubricating composition. 
   
   
       9 . The lubricating composition of  claim 1 , wherein the amine-containing friction modifier is a primary or secondary hydrocarbyl amine, a hydroxyalkyl amine, or mixtures thereof. 
   
   
       10 . The lubricating composition of  claim 9 , wherein the amine-containing friction modifier is a hydroxyalkyl amine. 
   
   
       11 . The lubricating composition of  claim 1 , wherein the amine-containing friction modifier is a tertiary amine. 
   
   
       12 . The lubricating composition of  claim 1 , wherein the amine-containing friction modifier is present at 0.02 wt % to 2 wt % of the lubricating composition. 
   
   
       13 . The lubricating composition of  claim 1 , wherein the lubricating composition is further characterised as having at least one of (i) a sulphur content of 0.8 wt % or less, (ii) a phosphorus content of 0.2 wt % or less, or (iii) a sulphated ash content of 2 wt % or less. 
   
   
       14 . The lubricating composition of  claim 1 , wherein the lubricating composition is characterised as having (i) a sulphur content of 0.5 wt % or less, (ii) a phosphorus content of 0.1 wt % or less, and (iii) a sulphated ash content of 1.5 wt % or less. 
   
   
       15 . The lubricating composition of  claim 1  further comprises at least one of a viscosity modifier, an antioxidant, an overbased detergent, a succinimide dispersant, or mixtures thereof. 
   
   
       16 . The lubricating composition of  claim 1  further comprising a phosphorus-containing antiwear agent. 
   
   
       17 . The lubricating composition of  claim 1  further comprising an overbased detergent, wherein the overbased detergent is selected from the group consisting of non-sulphur-containing phenates, sulphur-containing phenates, sulphonates, salixarates, salicylates, and mixtures thereof. 
   
   
       18 . (canceled) 
   
   
       19 . A method of lubricating an internal combustion engine comprising, supplying to the internal combustion engine the lubricating composition of  claim 1 . 
   
   
       20 . The lubricating composition of  claim 1 , wherein the amine-containing friction modifier is present at 0.05 wt % to 1 wt % of the lubricating composition. 
   
   
       21 . The lubricating composition of  claim 1 , wherein the amine-containing friction modifier is present at 0.05 wt % to 1 wt % of the lubricating composition, and wherein the ashless antiwear agent is present at 0.1 to 5 wt % of the lubricating composition. 
   
   
       22 . The lubricating composition of  claim 1  wherein the ashless antiwear agent is derived from citric acid.