Effect of a Cu-Ferrite Catalyzed DPF on the Ultrafine Particle Emissions from a Light-Duty Diesel Engine

The emissions of diesel engines in terms of particulate matter are limited all over the world. One possible solution for reaching the target imposed by the various regulations could be the adoption of a catalytic diesel particulate filter (CDPF). Nevertheless, the effect of CDPFs on the particle size distributions (PSDs) during the regeneration process needs to be deeply investigated. Therefore, this research work is focused on a detailed PSD analysis during the active regeneration of a 30 %wt CuFe2O4 loaded CDPF at the exhaust of an L-D diesel engine to reach a more complete understanding of the filter behavior. The results of the experimental tests evidence that at the CDPF outlet, compared to a standard DPF: (i) during the start-up of the regeneration, the particle emissions are three orders of magnitude lower and remain two orders of magnitude lower for particle sizes larger than 50 nm; (ii) the PSDs measured in the time range of 200-450 s exhibit the bimodality observed during the accumulation phase, with a peak that is three orders of magnitude lower; (iii) at the end of the regeneration, the PN distribution exhibits reductions of two and three orders of magnitude for particle sizes of 5 nm and above 50 nm, respectively.