NO_2 Reduction, Passive and Active Soot Regeneration Performance of a Palladium-Base Metal Coating on Sic Filters

摘要

Silicon carbide diesel paniculate filter (DPF) is now recognized as the most effective and robust way to reduce not only the mass but also the number of emitted particles on diesel passenger cars. Widespread use of expensive catalytic platinum containing coatings has contributed to increased harmful NO_2 emissions. A novel low cost palladium-base metal coating, BMC-211, was developed which assists soot regeneration by oxygen transport and which actively removes NO_2 still having comparable passive and active soot regeneration properties. The novel coating was tested against a traditional commercial platinum coating on a modern series produced car, on chassis dynamometer and on engine test bench. The test results obtained demonstrate that palladium-base metal coating has significantly lower NO_2 emission during NEDC tests compared to traditional Pt-coating, both for fresh and aged samples, and showed at least the same performance concerning passive regeneration, forced regeneration, pressure drop, regulated NEDC emissions and secondary emissions. The silicon carbide filter material is not mechanically affected by the coating.