title: Photoacoustic analyzer for the artifact-free parallel detection of soot and NO2 in engine exhaust.
abstract: Soot particles and NO(2) are among the most hazardous emissions from diesel combustion engines. Currently, no analytical system exists which allows for the simultaneous, time-resolved online analysis of these two components. Furthermore, state-of-the-art NO(2) analyzers for exhaust gas require particle filtration prior to the analysis, which may induce artifacts and measurement errors. We present a photoacoustic instrument which overcomes these drawbacks. The sensitivity of the instrument (LOD(NO(2)) = 0.3 ppm, LOD(soot) = 0.54 μg m(-3), limit of detection/quantification) as well as the temporal resolutions are dictated by the needs of typical automotive applications. Also required for this specific application, we developed PA cells which can be heated to 80 °C, while the microphones maintain a temperature of 45 °C. Setup and specific parameters of the instrument are discussed, and the results of typical engine tests are compared to reference analytical instrumentation.
authors.forename: Christoph
authors.initials: C
authors.lastname: Haisch
authors.forename: Reinhard
authors.initials: R
authors.lastname: Niessner