Lubricating compositions for preventing or reducing pre-ignition in an engine

Abstract

Disclosed is the use of a lubricating composition including at least one base oil and at least one polyalkylene glycol (PAG) produced by polymerisation or copolymerisation of alkylene oxides including between 3 and 8 carbon atoms, at least one of which being a butylene oxide, for preventing or reducing pre-ignition in an engine, preferably in a vehicle engine.

1 - 9 . (canceled) 
     
     
         10 . Method to prevent or reduce pre-ignition in an engine comprising the lubrifiation of said engine with a lubricating composition comprising at least one base oil and at least polyalkylene glycol (PAG) obtained by polymerisation or copolymerisation of alkylene oxides having 3 to 8 carbon atoms, including at least one butylene oxide. 
     
     
         11 . The method according to  claim 10 , wherein the PAG is a PAG of formula (A): 
       
         
           
           
               
               
           
         
         where:
 Y 1  and Y 2  are each independently a hydrogen atom or hydrocarbon group; 
 n is an integer of 2 or higher; 
 x represents one or more integers ranging from 1 to n; 
 the groups R 2x-1  and R 2x  are each independently a hydrogen atom or hydrocarbon group having 1 to 6 carbon atoms, 
 
         the sum of the number of carbon atoms of R 2x-1  and R 2x  is equal to 2 for at least one value of x. 
       
     
     
         12 . The method according to  claim 10 , wherein the PAG is a PAG of formula (A) where:
 Y 2  is a hydrogen atom;   R 2x-1  and R 2x , the same or different, are independently a hydrogen atom or C 1 -C 2 -alkyl group.   
     
     
         13 . The method according to  claim 10 , wherein the PAG is a PAG of formula (B): 
       
         
           
           
               
               
           
         
         where:
 R1 is a straight-chain or branched C 8 -C 12 -alkyl group; 
 p is an integer ranging from 2 to 10; 
 q is an integer ranging from 2 to 10. 
 
       
     
     
         14 . The method according to  claim 10 , wherein the weight content of PAG, relative to the total weight of the composition, ranges from 5 to 50%. 
     
     
         15 . The method according to  claim 10 , wherein the lubricating composition also comprises an additive selected from among from among friction modifiers, detergents, anti-wear additives, extreme-pressure additives, viscosity index improvers, dispersants, antioxidants, pour point improvers, defoamers, thickeners and mixtures thereof. 
     
     
         16 . The method according to  claim 10  wherein the engine is a vehicle engine. 
     
     
         17 . The method according to  claim 10 , wherein the pre-ignition is low speed pre-ignition (LSPI) and the engine is a vehicle engine. 
     
     
         18 . The method of  claim 11 , wherein Y 1  and Y 2  are each a C 1 -C 30  alkyl or alkylphenyl group. 
     
     
         19 . The method of  claim 18 , wherein n is less than 500. 
     
     
         20 . The method of  claim 18 , wherein n is in a range of 2 to 200. 
     
     
         21 . The method of  claim 18 , wherein n is in a range of 2 to 60. 
     
     
         22 . The method of  claim 18 , wherein n is in a range of 5 to 30. 
     
     
         23 . The method of  claim 18 , wherein n is in a range of 7 to 20. 
     
     
         24 . The method of  claim 18 , wherein n is in a range of 7 to 15. 
     
     
         25 . The method of  claim 18 , wherein the groups R2x-1 and R2x are each independently a straight-chain or branched C1-C6 alkyl group. 
     
     
         26 . The method of  claim 13 , wherein p is an integer ranging from 2 to 6. 
     
     
         27 . The method of  claim 13 , wherein q is an integer ranging from 2 to 6. 
     
     
         28 . The method of  claim 14 , wherein the weight content of PAG, relative to the total weight of the composition, ranges from 10 to 40%. 
     
     
         29 . The method of  claim 14 , wherein the weight content of PAG, relative to the total weight of the composition, ranges from 15 to 30%.