Lubricant compositions comprising colloidal dispersions of iron and treatment of engine exhaust gases therewith

Abstract

Lubricant compositions contain a blend of a lubricating oil and a colloidal dispersion of particles of at least one iron compound and an amphiphilic agent; such compositions are useful for operating an engine, more particularly a diesel engine, which is equipped with an exhaust system fitted with a particle filter, wherein the particles present in the exhaust gases are trapped on the filter and, periodically, the trapped particles are burned, and further wherein the subject compositions are employed as engine lubricants with a view to catalyzing the combustion of the trapped particles.

1 .- 10 . (canceled) 
   
   
       11 . A lubricant composition which comprises admixture of:
 a lubricating oil; and   a colloidal dispersion of particles of at least one iron compound and an amphiphilic agent which at least partially interacts therewith.   
   
   
       12 . The lubricant composition as defined by  claim 11 , wherein at least 85% of the iron compound particles are primary particles. 
   
   
       13 . The lubricant composition as defined by  claim 11 , wherein the iron compound particles have a D 50  ranging from 1 to 5 nm 
   
   
       14 . The lubricant composition as defined by  claim 11 , said amphiphilic agent comprising an acid. 
   
   
       15 . The lubricant composition as defined by  claim 14 , said acid comprising a carboxylic acid having from 10 to 60 carbon atoms. 
   
   
       16 . The lubricant composition as defined by  claim 14 , said acid being selected from the group consisting of fatty acids of tall oil, of soybean oil, of tallow or of linseed oil, oleic acid, linoleic acid, stearic acid and isomers thereof, pelargonic acid, capric acid, lauric acid, myristic acid, dodecylbenzenesulfonic acid, 2-ethylhexanoic acid, naphthenic acid, hexoic acid, toluenesulfonic acid, toluenephosphonic acid, laurylsulfonic acid, laurylphosphonic acid, palmitylsulfonic acid and palmitylphosphonic acid. 
   
   
       17 . The lubricant composition as defined by  claim 11 , wherein the iron content, expressed as metal iron, comprising the colloidal dispersion therein, is at most 6% by weight with regard to the total weight thereof. 
   
   
       18 . A method for operating an engine producing exhaust gases that contain particulates and equipped with a muffler provided with a particulate filter, in which the particulates are trapped on said filter and the catalytic combustion of the trapped particulates is carried out periodically, wherein, to assist catalyzing the combustion of said particulates, a lubricant composition as defined by  claim 11  is provided for said engine. 
   
   
       19 . The method as defined by  claim 18 , wherein the engine is a diesel engine or a petrol engine. 
   
   
       20 . The method as defined by  claim 18 , carried out employing an engine operating with a fuel which contains a catalyst for combustion of the particulates or with an engine equipped with a muffler which comprises a catalytic particulate filter. 
   
   
       21 . The lubricant composition as defined by  claim 11 , said amphiphilic agent comprising a phosphate. 
   
   
       22 . The lubricant composition as defined by  claim 13 , said D 50  ranging from 3 to 4 nm. 
   
   
       23 . The lubricant composition as defined by  claim 15 , comprising a carboxylic acid having from 15 to 25 carbon atoms. 
   
   
       24 . The lubricant composition as defined by  claim 17 , said iron content being at most 1%. 
   
   
       25 . The lubricant composition as defined by  claim 11 , comprising particles of iron oxide and/or hydroxide and/or oxyhydroxide. 
   
   
       26 . The lubricant composition as defined by  claim 25 , said particles comprising a complexing agent. 
   
   
       27 . The lubricant composition as defined by  claim 11 , said colloidal particles being suspended in an organic liquid phase. 
   
   
       28 . An internal combustion engine oil comprising the lubricant composition as defined by  claim 11 .