Partial wall-flow filter and method

Abstract

A partial wall-flow filter having some unplugged flow-through channels and some plugged channels. Desirable combinations of filtration efficiency and back pressure may be provided by combinations of t wall <= 305 urn, MPD <= 20 [mu]m, %P >= 50 %, and CD >= 250 cpsi wherein t wall is the transverse thickness of the porous walls, MPD is a mean pore diameter of the porous walls, %P is the total porosity of the porous walls, and CD is the cell density of the channels. In one embodiment, some of the plugged channels are located adjacent to the inlet end and some are located adjacent to the outlet end. Systems and method including the partial wall-flow filter are also described.

Description

[0001] Cross References to Related Applications [0002] This application claims priority to US Provisional Application No. 61 / 057,079, filed May 29, 2008. field of invention [0003] This invention relates generally to wall flow filters for filtering exhaust gases, and more particularly to wall flow filters having some plugged channels and some unplugged channels. Background technique [0004] Diesel exhaust systems may include, for example, a diesel particulate filter (DPF) for removing particulates, such as soot, from diesel exhaust. The most widely used DPF is the wall flow filter. Conventional wall flow filters comprise a ceramic honeycomb body having longitudinal, generally parallel cell channels formed by a plurality of intersecting porous walls. The cells are typically plugged with a ceramic plugging cement to form a tessellated pattern of plugging at the ends of the honeycomb body. The cell cells of the filter typically have some unplugged ends at the inlet end o...

AI Technical Summary

Problems solved by technology

"Active" regeneration, on the other hand, comes with fuel economy drawbacks

Additionally, conventional filters can have relatively high back pressure

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