TY - JOUR A1 - Walter, Stefanie A1 - Schwanzer, Peter A1 - Hagen, Gunter A1 - Rabl, Hans-Peter A1 - Dietrich, Markus A1 - Moos, Ralf T1 - Soot Monitoring of Gasoline Particulate Filters Using a Radio-Frequency-Based Sensor T2 - Sensors N2 - Owing to increasingly stringent emission limits, particulate filters have become mandatory for gasoline-engine vehicles. Monitoring their soot loading is necessary for error-free operation. The state-of-the-art differential pressure sensors suffer from inaccuracies due to small amounts of stored soot combined with exhaust gas conditions that lead to partial regeneration. As an alternative approach, radio-frequency-based (RF) sensors can accurately measure the soot loading, even under these conditions, by detecting soot through its dielectric properties. However, they face a different challenge as their sensitivity may depend on the engine operation conditions during soot formation. In this article, this influence is evaluated in more detail. Various soot samples were generated on an engine test bench. Their dielectric properties were measured using the microwave cavity perturbation (MCP) method and compared with the corresponding sensitivity of the RF sensor determined on a lab test bench. Both showed similar behavior. The values for the soot samples themselves, however, differed significantly from each other. A way to correct for this cross-sensitivity was found in the influence of exhaust gas humidity on the RF sensor, which can be correlated with the engine load. By evaluating this influence during significant humidity changes, such as fuel cuts, it could be used to correct the influence of the engineon the RF sensor. KW - dielectric properties KW - engine test bench KW - gasoline particulate filter (GPF) KW - microwave cavity perturbation KW - radio-frequency (RF) KW - soot mass determination Y1 - 2023 UR - https://opus4.kobv.de/opus4-oth-regensburg/frontdoor/index/index/docId/6557 SN - 1424-8220 N1 - This research work was funded by the Bavarian Research Foundation (Bayerische Forschungsstiftung, BFS) as part of the project “Load Sensor for GPF” (AZ-1288-17). VL - 23 IS - 18 SP - 1 EP - 19 PB - MDPI ER -