Method of Lubricating an Aluminum Silicate Composite Surface with a Lubricant Comprising Ashless, Sulphur, Phosphorous Free Antiwear Agent

Abstract

The present invention relates to a method of lubricating an aluminium-composite surface by supplying to the aluminium composite surface (typically an internal combustion engine aluminium surface) a lubricating composition comprising an oil of lubricating viscosity and an ashless antiwear agent.

1 - 20 . (canceled) 
   
   
       21 . A method of lubricating an internal combustion engine comprising an aluminium composite surface, the method comprising supplying to the aluminium composite surface a lubricating composition comprising an oil of lubricating viscosity and an ashless, phosphorus-free, sulphur-free antiwear agent. 
   
   
       22 . The method of claim  1 , wherein the aluminium composite surface is an aluminium-silicate surface. 
   
   
       23 . The method of claim  1 , wherein the ashless antiwear agent is derived from at least one of a hydroxy-carboxylic acid di-ester, a hydroxy-carboxylic acid di-amide, a hydroxy-carboxylic acid imide, a hydroxy-carboxylic acid di-imide, a hydroxy-carboxylic acid ester-amide, a hydroxy-carboxylic acid ester-imide, and a hydroxy-carboxylic acid imide-amide. 
   
   
       24 . The method of claim  1 , wherein the ashless antiwear agent is represented by a compound of Formula (1a) and/or (1b): 
     
       
         
         
             
             
         
       
     
     wherein
 n′ is 0 to 10, 01 to 6, 0 to 4, 1 to 4, or 1 to 2 for Formula (1b), and 1 to 10, 1 to 4, or 1 to 2 for Formula (1a); 
 p is 1 to 5, or 1 to 2, or 1; 
 Y and Y′ are independently —O—, >NH, >NR 3 , or an imide group formed by taking together both Y and Y′ groups in (1b) or two Y groups in (1a) and forming a R 1 —N< group between two >C═O groups; 
 X is independently —CH 2 —, >CHR 4  or >CR 4 R 5 , >CHOR 6 , or >C(CO 2 R 6 ) 2 , >C(OR 6 )CO 2 R 6 , >C(CH 2 OR 6 )CO 2 R 6 , —CH 3 , —CH 2 R 4  or CHR 4 R 5 , —CH 2 OR 6 , or —CH(CO 2 R 6 ) 2 , ═C—R 6 , or mixtures thereof to fulfill the valence of Formula (1a) and/or (1b), with the proviso that ═C—R 6  only applies to Formula (1a); 
 R 1  and R 2  are independently hydrocarbyl groups, typically containing 1 to 150, 4 to 30, 6 to 20, 10 to 20, or 11 to 18 carbon atoms; 
 R 3  is a hydrocarbyl group; 
 R 4  and R 5  are independently keto-containing groups (such as acyl groups), ester groups or hydrocarbyl groups; and 
 R 6  is independently hydrogen or a hydrocarbyl group, typically containing 1 to 150 carbon atoms. 
 
   
   
       25 . The method of  claim 24 , wherein Y and Y′ are both —O—. 
   
   
       26 . The method of  claim 21  wherein the ashless antiwear agent is derived from tartaric acid or citric acid. 
   
   
       27 . The method of  claim 21 , wherein the ashless antiwear agent is present at 0.05 to 10 wt % of the lubricating composition. 
   
   
       28 . The method of  claim 21 , wherein the ashless antiwear agent is present at 0.1 to 5 wt % of the lubricating composition. 
   
   
       29 . The method of  claim 21 , 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. 
   
   
       30 . The method of  claim 21 , 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. 
   
   
       31 . The method of  claim 21 , wherein the lubricating composition further comprises at least one of a friction modifier, a viscosity modifier, an antioxidant, an overbased detergent, a succinimide dispersant, or mixtures thereof. 
   
   
       32 . The method of  claim 31 , wherein the friction modifier is selected from the group consisting of long chain fatty amides, long chain fatty esters, long chain fatty epoxide derivatives, long chain fatty imidazolines, and amine salts of alkylphosphoric acids. 
   
   
       33 . The method of  claim 21 , wherein the lubricating composition further comprises a phosphorus-containing antiwear agent. 
   
   
       34 . The method of  claim 21 , wherein the lubricating composition further comprises further comprising a molybdenum compound, wherein the molybdenum compound is selected from the group consisting of molybdenum dialkyldithiophosphates, molybdenum dithiocarbamates, amine salts of molybdenum compounds, and mixtures thereof. 
   
   
       35 . The method of  claim 34 , wherein the molybdenum compound is present in an amount to provide 0.5 ppm to 2000 ppm of molybdenum. 
   
   
       36 . The method of  claim 21 , wherein the lubricating composition further comprises 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.