News Article

Particulate Filter Relies on RF
Date: Aug 19, 2014
Source: R&D Magazine ( click here to go to the source)

Featured firm in this article: Filter Sensing Technologies Inc of Malden, MA

RF-DPF Diesel Particulate Filter SensorJointly developed by Filter Sensing Technologies Inc., Massachusetts Institute of Technology and Oak Ridge National Laboratory, the RF-DPF Diesel Particulate Filter Sensor is a radio frequency (RF)-based sensor and control system used to measure the amount, type and distribution of contaminants on ceramic diesel particulate filters (DPFs). The RF-DPF is designed to deliver reduced engine fuel consumption, decreased maintenance costs and extended life for DPFs, which are expensive and required on all new diesel vehicles to meet strict emissions regulations.

The RF-DPF uses RF signals to provide a direct measure of the diesel particulate filter loading state. The system consists of one or two small probes or antennas mounted in the DPF housing. The probe(s) are connected to the RF sensor control unit, and consist of small stainless steel rod or stub antennas used to transmit and receive the RF signals.

The system is designed to operate with either a signal antenna (reflection mode) or dual antenna (transmission mode). The control unit contains low-cost circuit chips. Instead of using the wireless signal to transmit data, the wireless signal is used to conduct the measurements. The wireless signal propagates through the ceramic filter, but is fully contained in the metal filter housing. Soot, which is primarily composed of black carbon, strongly absorbs the RF signal. The decrease in signal strength can readily be correlated to the amount of soot accumulated on the filter.

Diesel particulate filter

Filter Sensing Technologies Inc.
Massachusetts Institute of Technology
Oak Ridge National Laboratory