Lubricating Oil Composition

Abstract

The invention relates to reducing friction coefficient in automotive lubricating oil, in particular although not exclusively at lower temperature by combining molybdenum dithiocarbamate additives with benzotriazole derivative corrosion inhibitors.

What is claimed is: 
     
         1 . An automotive engine lubricating oil composition comprising
 (A) a base oil of lubricating viscosity,   (B) at least one benzotriazole derivative represented by Formula (I):   
       
         
           
           
               
               
           
         
       
       wherein R 5  is a hydrocarbyl group having 1-3 carbon atoms and R 6  is a tertiary amine group represented by 
       
         
           
           
               
               
           
         
       
       wherein R 7  and R 8  are independently hydrocarbyl groups having 3 to 10 carbon atoms,
 (C) at least one molybdenum dithiocarbamate compound represented by either Formula (II) or Formula (III): 
 
       
         
           
           
               
               
           
         
       
       wherein R 1  through R 4  independently denote a straight chain, branched chain or aromatic hydrocarbyl group having 1 to 24 carbon atoms; and X 1  through X 4  independently denote an oxygen atom or a sulfur atom,
   Mo 3 S k L n Q z    Formula (III)
 
 
       wherein L are independently selected ligands having organo groups with a sufficient number of carbon atoms to render the compound soluble or dispersible in the oil, n is from 1 to 4, k is from 4 to 7, Q is selected from the group of neutral electron donating compounds, and z ranges from 0 to 5 and includes non-stoichiometric values, and
 (D) one or more additional additives chosen from metal containing or ashless detergents, ashless antioxidants, antiwear additives, corrosion inhibitors, rust inhibitors, viscosity index improvers, and dispersants, 
 
       wherein the lubricating oil composition comprises a total amount of from 100 to 2000 ppm molybdenum from components (C) and wherein the benzotriazole derivative (B) is present in the lubricating oil in an amount from 0.001 to 5 mass %. 
     
     
         2 . An automotive engine lubricating oil composition according to  claim 1 , wherein the benzotriazole derivative (B) has the following structure: 
       
         
           
           
               
               
           
         
       
     
     
         3 . An automotive engine lubricating oil composition according to  claim 1 , wherein the benzotriazole derivative (B) is present in an amount from 0.01 to 2 mass %, on an active matter basis. 
     
     
         4 . An automotive engine lubricating oil composition according to  claim 3 , wherein the benzotriazole derivative is present in the lubricating oil composition of the present invention in an amount of 0.01 to 0.04 mass %, on an active matter basis. 
     
     
         5 . An automotive engine lubricating oil composition according to  claim 1 , wherein the molybdenum dithiocarbamate compound (C) comprises only a dimeric molybdenum dithiocarbamate of Formula (II). 
     
     
         6 . An automotive engine lubricating oil composition according to  claim 1 , wherein the molybdenum dithiocarbamate compound (C) comprises a mixture of dimeric molybdenum dithiocarbamate of Formula (II) and trimeric molybdenum dithiocarbamate of Formula (III). 
     
     
         7 . An automotive engine lubricating oil composition according to  claim 1 , wherein the lubricating oil composition comprises a total amount of from 450 to 2000 ppm molybdenum from molybdenum dithiocarbamate component (C). 
     
     
         8 . An automotive engine lubricating oil composition according to  claim 7 , wherein the molybdenum dithiocarbamate compound (C) provides the lubricating oil composition with from 600 to 900 ppm molybdenum. 
     
     
         9 . An automotive engine lubricating oil composition according to  claim 1 , further comprising an aminic friction modifier having a structure: 
       
         
           
           
               
               
           
         
       
     
     
         10 . An automotive engine lubricating oil composition according to  claim 9 , wherein the amount of aminic friction modifier of Formula (IV) in the lubricating oil composition does not exceed 5 mass %, based on the total mass of the lubricating oil composition. 
     
     
         11 . An automotive engine lubricating oil composition according to  claim 10 , wherein the amount of aminic friction modifier of Formula (IV) in the lubricating oil composition does not exceed 2 mass %, based on the total mass of the lubricating oil composition. 
     
     
         12 . An automotive engine lubricating oil composition according to  claim 11 , wherein the amount of aminic friction modifier of Formula (IV) in the lubricating oil composition does not exceed 0.5 mass %, based on the total mass of the lubricating oil composition. 
     
     
         13 . An automotive engine lubricating oil composition according  claim 1 , wherein the lubricating oil composition further comprises one or more metal detergents that are neutral or overbased alkali or alkaline earth metal salicylates. 
     
     
         14 . An automotive engine lubricating oil composition according  claim 13 , wherein the lubricating oil composition further comprises one or more metal detergents that are neutral or overbased magnesium and/or calcium salicylate detergents. 
     
     
         15 . An automotive engine lubricating oil composition according to  claim 1 , wherein the lubricating oil composition further comprises one or more oil-soluble zinc dihydrocarbyl dithiophosphates. 
     
     
         16 . A method of lubricating an automotive engine comprising lubricating the engine with an automotive engine lubricating oil composition as claimed in  claim 1 .