Design principles for controlling soot deposition location in resistive PM sensors

• Published in: Sensors and actuators. A. Physical. Vol. 330; p. 112871
• Main Authors: Bilby, David, Kubinski, David
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15-10-2021; Elsevier BV
• Subjects: Aerosol trajectory model; Chemical vapor deposition; Deposition; Electrodes; Fluid filters; PM sensor design principles; Sensors; Soot; Soot sensor; Studies; Switching; Thin films; PM sensor design principles; Soot sensor; Aerosol trajectory model
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/j.sna.2021.112871

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•Soot deposition location is affected by electrode angle relative to flow and electrode finger width.•Agreement between experimental and simulated soot deposition due to interaction between flow, electric and thermal fields.•Sensors with 68 μm wide electrodes angled 67° relative to flow respond fastest, but no strong trends in angle, width emerge.•Summary metrics of simulated soot deposition do not reproduce fine features of experimental sensor response trends.
Resistive soot sensors remain attractive due to their simplicity but tightening diesel particulate filter monitoring regulations necessitate more sensitive soot measurement. We studied the influence of inter-digital electrode (IDE) pattern design on deposition location control as a means to concentrate soot and improve resistive soot sensor response. Sensors with five electrode angles from 0° to 90° relative to flow as well as three electrode widths from 68 μm to 585 μm are included in our design study. We observe deposition primarily around the periphery of the IDE pattern on narrow electrode width samples, with increasing coverage as width increases. The flow-aligned electrode fingers are an exception to this behavior, exhibiting dendrites across much of the IDE pattern area. Samples with electrode fingers angled relative to flow primarily show deposition on the downstream side of IDE fingers, near the inter-electrode gap edge. Despite this control over how much of the IDE pattern collects signal-generating dendrites and control over the proximity of soot deposition trajectories to the inter-electrode gap, we do not observe dramatically improved sensitivity.