Beschreibung:
<jats:p>Abstract. For the purposes of the onboard diagnosis (OBD) of diesel particulate
filters (DPFs) in diesel exhaust treatment systems, a particulate matter
(PM) sensor is applied downstream from the DPFs to detect small amounts of
diesel soot that passed through the filter. The state-of-the-art technology is a sensor based on the resistive measurement principle, i.e., charged soot particles are attracted by electrophoretic forces, deposited on an interdigital electrode (IDE) structure and conductive soot bridges that reduce the overall resistance are formed. This paper reports
how the response time of a resistively working particulate matter sensor can be
shortened up to 30 % by the optimization of soot deposition
that is initiated by a change in the sensor operation strategy. The
measurement voltage is applied for prepolarization during the sensor regeneration phase rather than during the cooling phase before the
measurement is commonly done. Experiments were performed at diesel
engine test benches to examine this context and simulations of
the electric field above and below the IDE structure. The data are used
to deduct a model, including the solid state chemistry of the sensor's
ceramic materials, the effect of impurities on the electric field
properties and the interconnection with the soot deposition, which
defines the sensor's response.
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