Influencing Parameters on the Microwave-Based Soot Load Determination of Diesel Particulate Filters

Titelangaben

Feulner, Markus ; Seufert, Florian ; Müller, Andreas ; Hagen, Gunter ; Moos, Ralf:
Influencing Parameters on the Microwave-Based Soot Load Determination of Diesel Particulate Filters.
2015
Veranstaltung: CAPOC10 : 10th International Congress on Catalysis and Automotive Pollution Control , 28.-30.10.2015 , Brussels, Belgien.
(Veranstaltungsbeitrag: Kongress/Konferenz/Symposium/Tagung , Poster )

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Abstract

Diesel particulate filters (DPF) are in serial use to meet the very tight particulate emission limits. Recently, a novel method for measuring the actual trapped soot mass inside a DPF was introduced of several groups. Electromagnetic waves in the low GHz range are emitted inside the metallic canning of a DPF, which represents a cavity resonator. Inside this resonator, a characteristic field distribution with standing waves (resonance modes) forms out. In case of a filter element mounted inside the resonator, the material properties (permittivity, conductivity) change with soot accumulation and therefore the field distribution changes as well. By measuring the reflection or transmission parameters of the electromagnetic field, S11 or S21, respectively, various parameters can be derived, like resonance frequency or others, which can be correlated to soot mass in the DPF. The absolute value of the transmission parameter, e.g., describes the power transmission through the filter. It is strongly affected by electronic losses that stem from soot. The general suitability of this method for in situ soot load determination has been already presented, e.g. at CAPoC 9. The aim of the present study is to examine the influence of different parameters, like exhaust gas temperature, humidity or diesel ashes. Therefore, a laboratory set up was built to vary the different parameters independently.