Experimental study on transient filtration efficiency of diesel particulate filter

This paper explores the critical issue of substantial particulate emissions during the start-up stage of internal combustion engines equipped with Diesel Particulate Filter/Gasoline Particulate Filter (DPF/GPF), focusing on the Transient Filtration Efficiency (TFE) of DPF. It is pivotal in meeting the stringent Euro VII regulations and reaching near-zero emission targets. Initially, the filtration characteristics of DPF during cold start and warm start are investigated based on a diesel engine test bench, and the performance of particulate emissions at the inlet and outlet of DPF are presented. Subsequently, a small-scale simulation test bench is built to study the effect of inlet flow rate and particle number concentration on the transient filtration characteristics of the filter. The results reveal that the inlet peak Particle Number Flow Rate (PNFR) has a significant effect on TFE. Additionally, it examines the effects of filter substrate characteristics, finding that increasing the temperature and particle loading can effectively improve TFE. Assembling the studies above, future work will delve into the combined effects of various factors on transient filtration efficiency, such as particle size distribution, PNFR and temperature, with the aim of searching for an optimization window to reduce the particulate emissions from the DPF during engine start-up stage.