Abstract: A particulate filter control system and method for controlling the same is disclosed. The particulate filter load monitoring system may transmit radio frequency signals through the resonant cavity and filter medium across a frequency range sufficient to generate more than one resonant mode. The system may contain additional sensors for monitoring additional exhaust characteristics and parameters. Further, a control unit may be configured to determine the amount of material accumulated in the particulate filter, detect failures and malfunctions of the exhaust after-treatment system and its associated components, and initiate an action based on the amount of material accumulated in the particulate filter, the determination of a system failure or malfunction, or input from one or more exhaust sensors.

Abstract: A system and method for determining loading of a filter having a first dielectric constant with a material having a different dielectric constant, is disclosed. The filter is contained within a metallic container forming a microwave cavity, and microwave or RF energy is created within the cavity and changes in the cavity microwave response are monitored. The changes in cavity microwave response are related to filter loading. In a preferred embodiment, the microwave energy includes multiple cavity modes thereby allowing determination of spatial distribution of the contaminant material loading. In one embodiment, the microwave cavity response includes a shift in frequency of a resonant mode. Alternatively, the microwave cavity response includes a shift in quality factor Q of a resonant mode. The microwave cavity response may include a shift in amplitude or peak width of the microwave's signal at resonance.