Lubricating Composition Containing an Antiwear Agent

Abstract

The invention provides a method of lubricating an aluminium-alloy surface of an internal combustion engine comprising supplying to the aluminium-alloy surface a lubricating composition comprising an oil of lubricating viscosity and an alkali or alkaline earth metal phenate detergent. The phenate disclosed herein may further provide antiwear performance on the aluminium-alloy surface.

1 . A method of lubricating an aluminium-allay surface of an internal combustion engine comprising supplying to the aluminium-alloy surface a lubricating composition comprising an oil of lubricating viscosity and an alkali or alkaline earth metal phenate detergent, wherein the alkali or alkine earth metal phenate detergent delivers 0.75 wt % to 2 wt % of hydrocarbyl-substituted phenol to the lubricating composition;
 wherein said internal combustion engine has part or all of a cylinder bore, cylinder block, or piston ring composed of a eutectic or hyper-eutectic aluminium alloy.   
     
     
         2 . The method of  claim 1 , wherein the phenate detergent is lithium, sodium, calcium, magnesium, or barium phenate. 
     
     
         3 - 21 . (canceled) 
     
     
         22 . The method of  claim 1 , wherein the phenate detergent is a calcium sulphurised-phenate. 
     
     
         23 . The method of  claim 1 , wherein the phenate detergent is an overbased calcium sulphurised-phenate. 
     
     
         24 . The method of  claim 1 , wherein the lubricating composition comprises (a) an oil of lubricating viscosity, (b) an overbased alkali or alkaline earth metal phenate detergent having a TBN of 200 to 400, and further comprises (c) a neutral phenate with a TBN of 20 to 170. 
     
     
         25 . The method of  claim 1 , wherein the alkali or alkaline earth metal phenate detergent has a metal ratio of 4 to 8. 
     
     
         26 . The method of  claim 1 , wherein the alkali or alkaline earth metal phenate detergent delivers 1 wt % to 1.5 wt % of hydrocarbyl-substituted phenol to the lubricating composition. 
     
     
         27 . The method of  claim 1 , wherein the alkali or alkaline earth metal phenate detergent delivers 0.9 wt % to 1.75 wt % of hydrocarbyl-substituted phenol and anions thereof to the lubricating composition; and the sulphated ash content is at least 0.4 wt % to 1.3 wt % of the lubricating composition. 
     
     
         28 . The method of  claim 1 , wherein the alkali or alkaline earth metal phenate detergent delivers 0.9 wt % to 1.75 wt % of hydrocarbyl-substituted phenol to the lubricating composition; and the sulphated ash content is at least 0.4 wt % to 1.2 wt % of the lubricating composition. 
     
     
         29 . The method of  claim 1 , wherein the alkali or alkaline earth metal phenate detergent delivers 1 wt % or higher to 1.5 wt % of hydrocarbyl-substituted phenol to the lubricating composition; and the sulphated ash is at least 0.6 wt % to 1.1 wt % of the lubricating composition. 
     
     
         30 . The method of  claim 1 , wherein the sulphated ash content of the lubricating composition is at least 0.6 wt % up to 2 wt % of the lubricating composition. 
     
     
         31 . The method of  claim 1 , wherein the lubricating composition is characterised as having (i) a sulphur content of 0.5 wt % or less, a phosphorus content of 0.06 wt % or less, and (iii) a sulphated ash content of 1.3 wt % or less 
     
     
         32 . The method of  claim 1  further comprising a zinc dialkyldithiophosphate, or mixtures thereof, wherein the zinc dialkyldithiophosphates is present at 0.5 wt % to 2 wt % of the lubricating composition. 
     
     
         33 . The method of  claim 1  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. 
     
     
         34 . The method of  claim 1  further comprising an overbased detergent, wherein the overbased detergent is selected from the group consisting of sulphonates, salixarates, salicylates, and mixtures thereof. 
     
     
         35 . A method of lubricating an aluminium-alloy surface of an internal combustion engine comprising supplying to the aluminium-alloy surface a lubricating composition comprising an oil of lubricating viscosity and an alkali or alkaline earth metal phenate detergent;
 wherein the alkali or alkaline earth metal phenate detergent comprises (i) 0.25 to 1.5 wt % of an overbased alkali or alkaline earth metal phenate detergent having a TBN of 200 to 400 and (ii) 0.2 wt % to 8 wt % of a neutral phenate with a TBN of 20 to 170.   
     
     
         36 . The method of  claim 35  wherein the aluminium alloy is a eutectic or hyper-eutectic aluminium alloy. 
     
     
         37 . The method of  claim 35  wherein the internal combustion engine has part or all of a cylinder bore, cylinder block, or piston ring composed of an aluminium alloy, or aluminium composite.