Tartaric Acid Derivatives in HTHS Fluids

Abstract

The present invention provides high-HTHS value lubricating compositions that have improved fuel economy performance. The present invention also provides methods of operating an internal combustion engine utilizing such compositions. The lubricating compositions of the invention utilize butane dioic imide compounds, such as tartrimides, and may also be low sulfur, low ash and low phosphorus, providing lower wear and friction and improved fuel economy.

What is claimed is: 
     
         1 . A lubricant composition comprising
 (a) an oil of lubricating viscosity;   (b) an alkoxy or hydroxy substituted butane dioic imide friction modifier wherein the friction modifier is represented by formula I;   
       
         
           
           
               
               
           
         
       
       wherein R 1  is hydrocarbyl group containing from 8 to 30 carbon atoms; R 2  is —H or a hydrocarbyl group; Y is —H, —OH or —OR 2  with the proviso that when Y is —OR 2  the two R 2  groups may be linked to form a ring. 
     
     
         2 . The lubricant composition of  claim 1  wherein the composition is a low-sulfur, low-phosphorus and low-ash lubricant suitable for use in an internal combustion engine; and wherein the oil of lubricating viscosity is a high temperature high shear fluid. 
     
     
         3 . The lubricant composition of  claim 1  wherein the lubricant composition is a high temperature high shear fluid having a dynamic viscosity of at least 3.5 cP. 
     
     
         4 . The composition of  claim 1  wherein component (b) is derived from a material represented by formula II and an amine containing from 8 to 30 carbon atoms; 
       
         
           
           
               
               
           
         
       
       wherein R 2  is a hydrocarbyl group; Y is —H, —OH or —OR 2  with the proviso that when Y is —OR 2  the two R 2  groups may be linked to form a ring. 
     
     
         5 . The composition of  claim 4  wherein the amine comprises a linear amine containing from 16 to 20 carbon atoms. 
     
     
         6 . The composition of  claim 1  further comprising an additional friction modifier other than component (b), an overbased detergent, or combinations thereof. 
     
     
         7 . The composition of  claim 1  wherein component (b) comprises oleyl tartrimide. 
     
     
         8 . A method of lubricating an engine comprising the steps of:
 I. supplying to the engine a lubricant composition comprising: (a) an oil of lubricating viscosity; (b) an alkoxy or hydroxy substituted butane dioic imide friction modifier wherein the friction modifier is represented by formula I;   
       
         
           
           
               
               
           
         
       
       wherein R 1  is hydrocarbyl group containing from 8 to 24 carbon atoms; R 2  is a hydrocarbyl group; Y is —H, —OH or —OR 2  with the proviso that when Y is —OR 2  the two R 2  groups may be linked to form a ring. 
     
     
         9 . The method of  claim 8  wherein the engine is present in an automobile wherein the automobile meets Euro 4 and Euro 5 standards. 
     
     
         10 . The method of  claim 8  wherein the lubricant composition is a low-sulfur, low-phosphorus and low-ash lubricant suitable for use in an internal combustion engine; and wherein the oil of lubricating viscosity is a high temperature high shear fluid. 
     
     
         11 . The method of  claim 8  wherein the lubricant composition is a high temperature high shear fluid having a dynamic viscosity of at least 3.5 cP. 
     
     
         12 . The method of  claim 8  wherein component (b) is derived from a material represented by formula II and an amine containing from 8 to 30 carbon atoms; 
       
         
           
           
               
               
           
         
       
       wherein R 2  is a hydrocarbyl group; Y is —H, —OH or —OR 2  with the proviso that when Y is —OR 2  the two R 2  groups may be linked to form a ring. 
     
     
         13 . The method of  claim 12  wherein the amine comprises a linear amine containing from 16 to 20 carbon atoms. 
     
     
         14 . The method of  claim 8  wherein the lubricant composition further comprises an additional friction modifier other than component (b), an overbased detergent, or combinations thereof. 
     
     
         15 . The method of  claim 8  wherein component (b) comprises oleyl tartrimide.