Use of a phosphorus compound as a non-corrosive extreme-pressure and anti-wear additive in a lubricant for a propulsion system of an electric or hybrid vehicle

Abstract

The invention relates to the use of at least one phosphorus compound, which is free of sulfur and has no amine function, as an anti-wear and extreme-pressure additive in a lubricant composition for a propulsion system of an electric or hybrid vehicle. The invention also relates to the use of a lubricant composition comprising at least one phosphorus compound, which is free of sulfur and has no amine function, as an anti-wear and extreme-pressure additive, for lubricating and optionally cooling a propulsion system of an electric or hybrid vehicle, in particular for lubricating and cooling the electric motor and the power electronics of an electric or hybrid vehicle.

1 - 10 . (canceled) 
     
     
         11 . A method of improving the anti-wear properties of a lubricant composition for a propulsion system of an electric or hybrid vehicle, comprising:
 adding at least one phosphorus compound to a lubricant composition for lubricating the propulsion system,   wherein the at least one phosphorous compound is free of sulfur and amine functional groups.   
     
     
         12 . The method of  claim 11 , wherein the at least one phosphorus compound is selected from phosphate esters, phosphonate esters, phosphinate esters, phosphite esters, phosphine oxides, or a combination thereof. 
     
     
         13 . The method of  claim 11 , wherein the at least one phosphorus compound is selected from compounds of formula (I) below: 
       
         
           
           
               
               
           
         
         wherein: 
         s is 0 or 1; and 
         each X group is independently selected from —OR′ or R′ groups, wherein R′ represents a hydrocarbon group having from 1 to 24 carbon atoms; 
         when s is 0, each X group is an —OR′ group; and 
         when s is 1, at least two of the X groups are —OR′ groups. 
       
     
     
         14 . The method of  claim 11 , wherein the at least one phosphorus compound is selected from phosphate esters of formula (II) below: 
       
         
           
           
               
               
           
         
         wherein: 
         each R group is independently selected from linear or branched, C 1  to C 10  alkyl groups; and 
         each n is independently selected from 0, 1 or 2. 
       
     
     
         15 . The method of  claim 14 , wherein:
 each n is 1; and   each R group is a branched C 3  to C 6  alkyl group in a para position.   
     
     
         16 . The method of  claim 11 , wherein the at least one phosphorus compound is tri(isopropylphenyl) phosphate. 
     
     
         17 . The method of  claim 11 , wherein the at least one phosphorus compound is selected from phosphite esters of formula (II′) below: 
       
         
           
           
               
               
           
         
         wherein: 
         each R group is independently selected from linear or branched, C 1  to C 10  alkyl groups; and 
         each n is independently selected from 0, 1 or 2. 
       
     
     
         18 . The method of  claim 17 , wherein:
 each n is 1; and   each R group is a branched C 3  to C 6  alkyl group in a para position.   
     
     
         19 . The method of  claim 11 , wherein the at least one phosphorus compound is tris(2,4-di-tert-butylphenyl) phosphite. 
     
     
         20 . The method of  claim 11 , wherein the lubricant composition comprises from 0.01% and 10% by mass of the at least one phosphorus compound, relative to the total mass of the lubricant composition. 
     
     
         21 . The method of  claim 11 , wherein the lubricant composition comprises from 0.5% and 3% by mass of the at least one phosphorus compound, relative to the total mass of the lubricant composition. 
     
     
         22 . The method of  claim 11 , wherein the lubricating composition comprises at least one base oil selected from polyalkylene glycols, polyalphaolefins, esters of carboxylic acids, alcohols, or a combination thereof. 
     
     
         23 . A method of reducing wear in in a propulsion system of an electric or hybrid vehicle, the method comprising lubricating and/or cooling an electric motor and/or power electronics of the electric or hybrid vehicle with a lubricant composition comprising at least one phosphorus compound that is free from sulfur and amine functional groups. 
     
     
         24 . The method of  claim 23 , wherein the at least one phosphorus compound comprises tri(isopropylphenyl) phosphate, tris(2,4-di-tert-butylphenyl) phosphite, or a combination thereof. 
     
     
         25 . The method of  claim 23 , further comprising lubricating rolling bearings located between a rotor and a stator of the electric motor with the lubricant composition. 
     
     
         26 . The method of  claim 23 , further comprising lubricating a reduction gear of a transmission of the electric or hybrid vehicle with the lubricant composition. 
     
     
         27 . The method of  claim 23 , wherein the lubricating composition comprises, relative to the total mass of the lubricating composition:
 from 0.1% to 5% by mass of the at least one phosphorus compound;   from 50% to 99.5% by mass of at least one base oil selected from group III base oils, group IV base oils, group V base oils, or a combination thereof; and   optionally from 0.1 to 5% by mass of at least one additive selected from antioxidants, detergents, dispersants, pourpoint depressants, antifoam agents, or a combination thereof.   
     
     
         28 . The method of  claim 27 , wherein:
 the lubricating composition comprises from 0.5 to 3% by mass of the at least one phosphorus compound;   the at least one phosphorus compound is selected from tri(isopropylphenyl) phosphate, tris(2,4-di-tert-butylphenyl) phosphite, or a combination thereof; and   the lubricating composition comprises from 60 to 99% by mass of the at least one base oil.