In-situ vehicular soot sensor optimization based on quartz-enhanced photoacoustic spectroscopy

Abstract

A quartz-enhanced photoacoustic spectroscopy (QEPAS)-based soot sensor was optimized for rapid and in-situ vehicular emission measurements. To mitigate vibration-induced interference and enhance the sensor's signal intensity, hardware refinements such as off-line transducer coupling and acoustic micro-resonators were implemented. Additionally, a method for tracking changes in transducer resonance frequency was implemented to minimize measurement uncertainty, particularly under prolonged exposure to high temperatures and heavy sooting conditions. Consequently, experimental results demonstrated a four-fold increase in signal level and a reduction in measurement uncertainty exceeding 67%. The total measurement duration was maintained within 3 s, including data processing, to ensure high temporal resolution.