Electrical ignition device for regeneration of a particulate trap

Abstract

An ignition system is disclosed for regenerating a particulate trap (40-400 cells per lineal inch) used to filter the exhaust gas of an internal combustion engine, the particulate trap having an entrance face for receiving a gaseous flow therethrough. The system comprises: (a) flow guide means effective to direct a gaseous flow to such entrance face during filtration and during regeneration of the trap; (b) an open cell ceramic foam body (10-30) cells per lineal inch) extending across such flow guide means and having (i) a radially outer ring exit surface in contact with the radially outer portion of the entrance face, and (ii) an entrance throat remote from the particulate trap, the open cell foam body being effective to trap an ignitable collection of particulates from the exhaust gas during filtration; and (c) electrically energized resistance heating means stationed in a radially central portion of the open cell body adjacent to the entrance throat effective to heat the body during regeneration to a temperature effective to ignite the ignitable collection. The foam body is preferably shaped in a frusto-conical configuration having a neck to for said entrance throat at one end and an opposite end having a base perimeter defining the outer periphery of the ring surface; the neck of the foam body preferably has cast-in-place therein electrical resistance heating wires; the cross-sectional area of the neck is no greater than 20% of the cross-sectional area of the trap entrance face.