Method of Lubricating an Internal Combustion Engine

Abstract

The invention provides a method of lubricating an internal combustion engine in the presence of a contaminant amount of water. The invention further relates to the use of a derivative of a hydroxy-carboxylic acid or a monoester of a polyol and an aliphatic carboxylic acid as a rust inhibitor.

1 - 24 . (canceled) 
     
     
         25 . A method of lubricating an internal combustion engine with an engine capacity of six litres or less comprising supplying to said engine a lubricating composition comprising:
 (a) an oil of lubricating viscosity;   (b) either:
 (i) an amide, ester or imide derivative of a hydroxy-carboxylic acid, or 
 (ii) a monoester of a polyol and an aliphatic carboxylic acid; and 
   (c) a contaminant amount of water, wherein the water is present at 500 ppm or more.   
     
     
         26 . The method of  claim 25 , wherein the engine capacity is one litre or less. 
     
     
         27 . The method of  claim 25 , wherein the internal combustion engine is an outboard engine, inboard engine or stern drive engine. 
     
     
         28 . The method of  claim 25 , wherein the internal combustion engine is a gasoline 4-cycle engine. 
     
     
         29 . The method of  claim 25 , wherein the internal combustion engine is a gasoline 4-cycle outboard engine. 
     
     
         30 . The method of  claim 25 , wherein the lubricating composition contains at least 0.09 wt % to 3 wt % water. 
     
     
         31 . The method of  claim 25 , wherein the lubricating composition contains 550 ppm or more of water. 
     
     
         32 . The method of  claim 25 , wherein the lubricating composition contains at least 0.1 wt % to 0.5 wt % water. 
     
     
         33 . The method of  claim 25 , wherein the lubricating composition is characterised as having (i) a sulphur content of 0.5 wt % or less, (ii) a phosphorus content of 0.12 wt % or less, and (iii) a sulphated ash content of 1 wt % or less. 
     
     
         34 . The method of  claim 25 , wherein the lubricating composition is characterised as having a sulphated ash content of 0.05 wt % to 0.9 wt %. 
     
     
         35 . The method of  claim 25 , wherein the derivative of a hydroxy-carboxylic acid is selected from the group consisting of a hydroxy-polycarboxylic acid di-ester, a hydroxy-polycarboxylic acid di-amide, a hydroxy-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. 
     
     
         36 . The method of  claim 25 , wherein the derivative of a hydroxy-carboxylic acid is 
       
         
           
           
               
               
           
         
       
       wherein
 n′ is 0 to 10 for Formula (1b), and 1 to 10 for Formula (1a); 
 p is 1 to 5; 
 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 , or >C(OR 6 )CO 2 R 6 , or —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  (where □ equals three valences, and may only apply to Formula (1a)) or mixtures thereof to fulfill the valence of Formula (1a) and/or (1b); 
 R 1  and R 2  are independently hydrocarbyl groups; 
 R 3  is a hydrocarbyl group; 
 R 4  and R 5  are independently keto-containing groups, ester groups or hydrocarbyl groups; and 
 R 6  is independently hydrogen or a hydrocarbyl group. 
 
     
     
         37 . The method of  claim 25 , wherein the monoester of a polyol and an aliphatic carboxylic acid is glycerol monooleate.