Using aerosols to create Nano-scaled membranes that improve gasoline particulate filter performance and the development of Wafer-based membrane coated filter analysis (WMCFA) method

The very high filtration efficiency of diesel particulate filters (DPF) derives from the soot cake that rapidly forms on the walls of honeycomb wall-flow substrates. However, one cannot count on this for gasoline direct injection (GDI) engines, because of their much lower soot rates and the soot oxidation due to their higher exhaust temperatures. Therefore, the present paper explores the use of artificial aerosols to synthesis nano-scale membranes that mimic the soot cake in DPFs. The paper has two major goals. The first is to introduce a new wafer-based approach for rapid screening and evaluation of new nanoscale membranes and show that this provides very good guidance for the performance of full-size gasoline particulate filters (GPF) by performing detailed experimental comparisons in aspects of filtration efficiency, pressure drop, and loading behavior. The second is to demonstrate the feasibility of using the nano-scale membranes to improve GPF performance and evaluate how choices of particle characteristics and aerosol flow rate influence the quality of the nano-scale membranes. Our experiments demonstrate that membranes produced 1) with particles of larger aggregate size or 2) under lower face velocity yield 25-36% and 13-34% better performance (particle number-based efficiency versus pressure drop tradeoff), respectively, under the range of tested conditions.

Automated summary

This paper investigates the use of artificial aerosols to synthesize nano-scale membranes that mimic the soot cake in diesel particulate filters (DPF) for gasoline direct injection (GDI) engines. The experiments demonstrate that membranes produced with larger aggregate size particles or under lower face velocity yield better performance in terms of filtration efficiency and pressure drop.