Advanced Sensors for Next Generation Diesel Particulate Filter Systems
Alexander Sappok, Filter Sensing Technologies, Inc.
Accurate knowledge of diesel particulate filter (DPF) loading is critical for robust and efficient operation of the combined engine-exhaust aftertreatment system. Furthermore, upcoming on-board diagnostics regulations require systems be in place to detect DPF failures. This work describes the application of radio frequency (RF) – based sensing techniques to accurately measure DPF soot and ash levels and the spatial distribution of the accumulated material, as well as potential applications to detect filter failures.
A series of tests conducted with a 1.9L GM turbo diesel engine at Oak Ridge National Laboratory provide a direct comparison of the RF measurements with conventional pressure-based DPF sensing systems and laboratory soot emission measurement instruments (TEOM). Comparison with pressure drop measurements show the RF technique is unaffected by exhaust flow variations and exhibits a high degree of sensitivity to DPF soot loading and good dynamic response. Additional computational and experimental work further illustrates the spatial resolution of the RF measurements. Based on the experimental results, the RF technique shows significant promise for improving DPF control enabling optimized operation of the combined engine-aftertreatment system for improved fuel economy and extended DPF service life.