Diesel particulate trap based on a mass of fibrous filter material formed with longitudinal tunnels filled with flexible strands

摘要

A diesel particulate trap has a filtering element which is a mass of fibrous filter material that radially fills a tubular casing. The filtering element employs lofty yarn extending in straight lines in a repeating pattern, which lines of lofty yarn have been compacted to form a plurality of fibrous walls that intersect to form tunnels extending in the axial or longitudinal direction of the casing. Some of the tunnels are filled with plugs that afford structural integrity while others of the tunnels remain open. The ends of the filtering element are covered by endplates. Substantially one-half of the open tunnels are axially aligned with openings in the inlet endplate and with imperforate areas in the outlet endplate, and the other open tunnels are axially aligned with openings in the outlet endplate and with imperforate areas in the inlet endplate. Exhaust gases entering tunnels open to the inlet pass through the compact fibrous walls and exit through tunnels open to the outlet.