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The diesel particulate filter (DPF) has been used in the automobile industry for around a decade. As a key technology for emissions control the DPF design needs to be increasingly optimized to expand its function to deal with any emission not just particulate matter (PM). NOx emission regulations need to be met as well as CO2 targets through minimizing any fuel penalty. Cost is extremely important to deliver an effective after-treatment catalyst. Aluminum titanate and cordierite-based material DPFs are very cost effective in part because their properties allow monolith-manufacturing. Furthermore, geometrical design of the DPF channel structure can contribute to multi-functionalization of the DPF to provide further advantages. Square and asymmetric square-designed channel structures have been utilized on current after-treatment DPF systems.

Diesel Particulate Filter (DPF) requires higher capacity of ash materials, incombustible particulate matters derived from lubricant oil, engine wear, etc., for usage of long lifetime. Conventional DPF such as SiC-DPF has been developed by optimizing cell geometry as of octagonal inlet shapes and square outlet shapes, called as “Octosquare”. Thus-obtained SiC-DPF could improve the lifetime to previous type with square cell design. However, under ash/soot-loading, pressure drop between upstream and downstream DPF, involving in the fuel penalty for the vehicle itself, makes higher. On the other hand, it was previously proposed that aluminum titanate (AT) with hexagonal cell design shows lower pressure drop and higher endurance performance. The characteristic of the filter design consists of higher open frontal area, relating to higher ash capacity, and higher filtration area, enabling lower pressure drop with soot loading.

Introduction of novel European regulation for automotive exhaust gas requires higher performance for Diesel Particulate Filter (DPF) as well as for deNOx technology in the aftertreatment system on the diesel vehicles. An innovative DPF, “SC-AT”, has been developed by combination of material properties of aluminum titanate (AT) and advantageous hexagonal cell geometry (HEX). SC-AT has 1) higher thermal shock resistance originating from unique AT material, 2) higher ash capacity, and 3) extremely lower pressure drop at both initial and soot-loaded stages, coming from the asymmetric HEX design concept. In this paper, design concept and its validation for SC-AT through cold flow bench and engine bench are presented.