Sustained Soot Oxidation in Catalytically Coated Filters

The development of advanced Catalytic Diesel Particulate Filters (CDPFs) relies on the interplay of chemistry and geometry in order to enhance soot-catalyst proximity and achieve direct catalytic soot oxidation. An extensive set of well-controlled experiments has been performed to provide direct catalytic soot oxidation rates in CDPFs. To study the direct catalytic soot oxidation on CDPFs, base-metal catalysts have been applied to DPFs with a variety of coating technologies. All materials were loaded with soot under identical exhaust conditions and soot oxidation was studied using temperature programmed and isothermal techniques. It is demonstrated that advanced catalyst coating technologies can lead into sustained and even accelerated soot oxidation over the entire conversion range, overcoming the shortcomings of conventional catalytic coatings which do not sustain the soot oxidation rate as conversion proceeds.