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

Abstract

Disclosed is a method using a lubricating composition including at least one base oil and at least one organomolybdenum compound chosen from among molybdenum dithiophosphate compounds for preventing or reducing pre-ignition in an engine, preferably in a motor vehicle.

1 - 11 . (canceled) 
     
     
         12 . Method of prevention or reduction of pre-ignition in a vehicle engine, wherein the method comprises at least one step of contacting a mechanical part of the engine with a lubricating composition comprising at least one base oil and at least one organomolybdenum compound wherein the organomolybdenum compound is selected from among molybdenum dithiophosphate compounds (Mo-DTP). 
     
     
         13 . Method according to  claim 12 , wherein the organomolybdenum compound is a Mo-DTP compound comprising
 from 1 to 40% by weight of molybdenum, relative to the total weight of the Mo-DTP compound;   from 1 to 40% by weight of sulfur, relative to the total weight of the Mo-DTP compound;   from 1 to 10% by weight of phosphorus, relative to the total weight of the total weight of the Mo-DTP compound.   
     
     
         14 . Method according to  claim 12 , wherein the Mo-DTP compound is selected from among dimeric Mo-DTP compounds or trimeric Mo-DTP compounds. 
     
     
         15 . Method according to  claim 12 , wherein the Mo-DTP compound is a dimeric Mo-DTP compound of formula (C) 
       
         
           
           
               
               
           
         
         in which
 R3, R4, R9 and R10, which are identical or different, independently represent a hydrocarbon group chosen from alkyl, alkenyl, aryl, cycloalkyl or cycloalkenyl groups, 
 R5, R6, R7 and R8, which are identical or different, independently represent an oxygen atom or a sulfur atom. 
 
       
     
     
         16 . Method according to  claim 12 , wherein the Mo-DTP compound is a dimeric Mo-DTP compound of formula (C1) 
       
         
           
           
               
               
           
         
         in which R3, R4, R9 and R10, which are identical or different, independently represent a hydrocarbon group chosen from alkyl, alkenyl, aryl, cycloalkyl or cycloalkenyl groups. 
       
     
     
         17 . Method according to  claim 12 , wherein the Mo-DTP compound is a dimeric Mo-DTP compound of formula (C1) in which R3, R4, R9 and R10, which are identical, represent a C8-alkyl group. 
     
     
         18 . Method according to  claim 12 , wherein the content by weight of organomolybdenum compound, relative to the total weight of the lubricating composition, ranges from 0.05 to 3%. 
     
     
         19 . Method according to  claim 12 , wherein the lubricating composition further comprises an additional additive selected from among friction modifiers with the exception of Mo-DTP compounds, detergents, anti-wear additives, extreme additives pressure improvers, viscosity index improvers, dispersants, antioxidants, pour point improvers, defoamers, thickeners and mixtures thereof. 
     
     
         20 . Method according to  claim 12 , for preventing or reducing the low speed pre-ignition (LSPI) in an engine.