Characteristics of Collection Efficiency of Partial DPF and Number Concentration of Carbon Particles by $NO_2$ Concentration and Temperature

Abstract

Emission regulations on mass and NOx have become more stringent, and particle number emission limits will be added to the Euro V emission standards for the European Union. Metallic partial diesel particulate filters (DPFs) have been developed to resolve the pressure drop, but little research has been performed on the number concentration of partial DPFs, and little is known about the correlation among particles, $NO_2$ concentration, and temperature. We investigated the characteristics of partial DPF collection efficiency and particle number concentration at various temperatures and $NO_2$ concentrations. To simulate real diesel particulate matter, we generated carbon nanoparticles using the spark discharge method. Specific particles were then classified by a differential mobility analyzer. We measured the number concentration of the separated particles at the inlet and the outlet of the furnace for various temperatures and $NO_2$ concentrations using a scanning mobility particle spectrometer system consisting of a differential mobility analyzer and condensation particle counter. We also measured the relative penetration ratio to calculate the characteristics with change in temperature and $NO_2$ concentration, and analyzed the collection effects of the partial DPF for 40- and 79-nm sized carbon particles.