Automotive exhaust particle filter has nitrate-forming coating applied to porous substrate

An internal combustion engine has an exhaust filter that oxidizes trapped particles. The filter is coated with a nitrate-forming substance. The coating is a silver-based compound e.g. Ag, Ag2O, AgOH, AgNO3, AgCO3 or a mixture of these, including alkaline metals, alkaline earth metals, rare earths, or a mixture of these. The coating is applied to a finely-pored base. The coating is in elemental form, or as an oxide, hydroxide, carbonate or nitrate. The porous substrate is zirconium oxide, zirconium oxide with La, aluminum oxide, Mg-Al mixed oxides, La-aluminum oxide, Ceroxide, Titanium oxide, silicon oxide, Si-Al mixed oxide, a zeolite, or a mixture of these. Dans un filtre destiné à éliminer les particules des gaz d'échappement de moteurs à combustion interne, les particules piégées dans le filtre sont oxydées. Selon l'invention, le filtre est revêtu d'une matière solide formant des nitrates.