Lubricating Composition Containing an Antiwear Agent

Abstract

The invention provides a lubricating composition containing an oil of lubricating viscosity, a compound derived from the hydroxy-carboxylic acid and a nitrile compound. The invention further relates to a method of the lubricating an internal combustion engine with the lubricating composition.

1 .- 20 . (canceled) 
     
     
         21 . A lubricating composition comprising
 an oil of lubricating viscosity,   a nitrile compound having a general formula CH 3 (CH 2 ) m —C≡N, wherein m is 2 to 50; and   a compound which is a derivative of a hydroxy-carboxylic acid, represented by the formula:   
       
         
           
           
               
               
           
         
       
       wherein
 n and m are independently integers of 1 to 5; 
 X is an aliphatic or alicyclic group, or an aliphatic or alicyclic group containing an oxygen atom in the chain, or a substituent group of the foregoing types, said group containing up to 6 carbon atoms and having n+m available points of attachment; 
 each Y is independently —O—, >NH, or >NR 9  or two Ys together represent the nitrogen of an imide structure R 8 —N<formed between two carbonyl groups; and 
 each R 8  and R 9  are independently hydrogen or a hydrocarbyl group, provided that at least one R 8  or R 9  group is a hydrocarbyl group; each R 10  is independently hydrogen, a hydrocarbyl group or an acyl group, further provided that at least one —OR 10  group is located on a carbon atom within X that is α or β to at least one of the —C(O)—Y—R 8  groups, 
 wherein the lubricating composition is characterised as having a phosphorus content of 200 ppm to 600 ppm. 
 
     
     
         22 . The lubricating composition of  claim 21 , wherein the nitrile compound has general formula CH 3 (CH 2 ) m —C≡N, wherein m is 10 to 18. 
     
     
         23 . The lubricating composition of  claim 21 , wherein n and m both equal 1, or n=2 and m=1, or n and m both equal 2, or n=3 and m=1. 
     
     
         24 . The lubricating composition of  claim 21 , wherein n and m both equal 2. 
     
     
         25 . The lubricating composition of  claim 21 , wherein the hydroxy-carboxylic acid is a derivative of tartaric acid, or mixtures thereof. 
     
     
         26 . The lubricating composition of  claim 21 , wherein the nitrile and the compound which is a derivative of a hydroxy-carboxylic acid are present in amounts in the range of 0.05 wt % to 2 wt % and 0.05 wt % to 2 wt %, respectively, of the lubricating composition. 
     
     
         27 . The lubricating composition preceding  claim 21 , wherein the nitrile and the compound which is a derivative of a hydroxy-carboxylic acid are present in amounts in the range of 0.1 wt % to 1 wt % and 0.2 wt % to 1 wt %, respectively, of the lubricating composition. 
     
     
         28 . The lubricating composition preceding  claim 21 , wherein the nitrile and the compound which is a derivative of a hydroxy-carboxylic acid are present in amounts in the range of 0.2 wt % to 0.4 wt % and 0.2 wt % to 0.4 wt %, respectively, of the lubricating composition. 
     
     
         29 . The lubricating composition 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 200 ppm to 600 ppm, and (iii) a sulphated ash content of 1.5 wt % or less. 
     
     
         30 . The lubricating composition of  claim 21  further comprising at least one of an antiwear agent, a dispersant viscosity modifier, a friction modifier, a viscosity modifier, an antioxidant, an overbased detergent, or mixtures thereof. 
     
     
         31 . The lubricating composition of  claim 21  further comprising an overbased detergent, wherein the overbased detergent is selected from the group consisting of phenates, sulphur-containing phenates, sulphonates, salixarates, salicylates, and mixtures thereof. 
     
     
         32 . A method of lubricating an internal combustion engine comprising supplying to the internal combustion engine the lubricating composition of  claim 21 . 
     
     
         33 . The method of  claim 32 , wherein the internal combustion engine has a cylinder bore, cylinder block, or piston ring having a steel surface.