Smart Soot Sensor for Particulate Filter OBD

Influence of key parameters on the response of a resistive soot sensor

“…Therefore, the development of a cheap sensor effective for the measurement of both mass and particle number (PN) concentration is necessary. Resistive sensors are ones of the most promising solution for that purpose [Brunel et al (2013), Grob et al (2012), Hagen et al (2010)]. They are typically composed of an alumina substrate, where the sensing face consists of two interdigitated platinum electrodes [ Brunel et al (2013), Hagen et al (2010), Husted et al (2012), Ochs et al (2010)].…”

“…During soot loading, an initial threshold time is required to observe a significant increase in the conductance because the PM collection does not yet form any electrical connections between the electrodes. The second phase corresponds to an increase of the conductance with time explained by soot bridges which are continuously formed between the electrodes [Brunel et al (2013)]. When a polarization voltage is applied between the electrodes, the blind state (threshold time) is shorter because the production of dendrite-like paths is promoted [Brunel et al (2013), Ochs et al (2010)].…”

“…The second phase corresponds to an increase of the conductance with time explained by soot bridges which are continuously formed between the electrodes [Brunel et al (2013)]. When a polarization voltage is applied between the electrodes, the blind state (threshold time) is shorter because the production of dendrite-like paths is promoted [Brunel et al (2013), Ochs et al (2010)]. On the other side of the substrate, a platinum resistance is used to monitor and control the sensor temperature.…”

“…Periodically, the soot accumulated on the sensing electrodes is removed during active regenerations by heating the sensor at around 600°C. By performing several cycles of soot loading/regeneration, the sensor can give the PM mass concentration in pseudo real time with a response time of around 3 minutes [Brunel et al (2013)].…”

“…Starting from past results on a resistive soot sensor development in the frame of "Ciclamen 2" French National project [Brunel et al (2013)], the objective of the present study is to determine the impact of the PM size and concentration on the sensor response. Model soot particles issued form a gas burner have been produced with various characteristics in terms of size distributions, PN and mass concentrations.…”