Abstract: A particulate trap regeneration system is provided, which may include a particulate trap having a filter medium configured to remove one or more types of particulate matter from an exhaust flow of an engine and a regeneration device configured to reduce an amount of particulate matter in the particulate trap, as well as a radio frequency-based particulate loading monitoring system configured to determine an amount of particulate matter trapped by the filter medium. The particulate loading monitoring system may include at least one radio frequency transmitting probe configured to transmit radio frequency signals of predetermined magnitude and predetermined frequency toward the filter medium and at least one radio frequency receiving probe configured to receive and measure the magnitude of received radio frequency signals that pass through the filter medium.

Abstract: A system and method for detecting soot and or ash loading within a filter is provided. The method comprises the steps of transmitting a source RF signal through a filter, measuring a reflected RF signal, measuring a transmitted RF signal, calculating reflected power by comparing the source RF signal with the reflected RF signal, calculating attenuated power by comparing the source RF signal with the transmitted RF signal, and determining soot loading based on reflected power and transmitted power. The system and method may also determine ash loading.

Abstract: An apparatus for detecting the accumulation of particulate material on a filter medium formed of dielectric material and disposed in a chamber is provided. The apparatus is operable for generating and transmitting an RF signal through the filter medium and for monitoring the transmission loss of the signal through at least a portion of the filter medium so as to provide an indication of the content of particulate material accumulated on the filter medium. The apparatus includes an input antenna for transmitting the signal and having at least one antenna element extending longitudinally of the chamber and disposed within the filter medium; and an output antenna for receiving the signal transmitted by the input antenna and having at least one antenna element extending longitudinally of the chamber and disposed within the medium in parallel, spaced apart, axially overlapping relation with respect to the input antenna element.

Abstract: A method of detecting the accumulation of particulate material collected on a filter medium formed of dielectric material in a chamber having the property of a microwave waveguide or transmission line comprises the steps of exciting the chamber with a microwave signal and monitoring the transmission loss of the signal through the line to sense the effective dielectric loss factor and thereby to provide an indication of the concentration or level of particulate material accumulated on the filter medium.

Abstract: A filter assembly for an internal combustion engine comprises, in combination, a housing defining an exhaust gas passage having an inlet end and an outlet end and a cavity intermediate the inlet and outlet ends thereof and in serial fluid communication therewith, the cavity defining an electromagnetically resonant coaxial line waveguide, a filter disposed within the cavity for removing particulate products of combustion from exhaust gases passing through the cavity, and a mechanism for producing axisymmetrically distributed, standing electromagnetic waves within the cavity whereby to couple electromagnetic energy in the waves into lossy material in the cavity to produce heat for incinerating the particulate products of combustion accumulated on the filter.