Integrating NO<sub>x</sub> Sensor for Automotive Exhausts—A Novel Concept

Geupel, Andrea; Kubinski, David J.; Mulla, Shadab; Ballinger, Todd H.; Chen, Hai-Ying; Visser, J.H.; Moos, Ralf

doi:10.1166/sl.2011.1471

Cited by 19 publications

(17 citation statements)

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“…Suitable materials for the accumulation sensing mode are materials that have been successfully applied as storage components, for instance in filters or catalysts, e.g., lean NO x traps or selective catalytic reduction (SCR) materials storing NH 3 . Geupel et al (2011) applied NO x storage catalysts based on alkaline (earth) carbonates as coatings for NO x dosimeter operated at temperatures in the range of 300 to 400…”

Section: Suitable Materials For Accumulating Gas Sensorsmentioning

confidence: 99%

Overview on conductometric solid-state gas dosimeters

Marr

Groß²,

Moos

2014

J. Sens. Sens. Syst.

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Abstract. The aim of this article is to introduce the operation principles of conductometric solid-state dosimeter-type gas sensors, which have found increased attention in the past few years, and to give a literature overview on promising materials for this purpose. Contrary to common gas sensors, gas dosimeters are suitable for directly detecting the dose (also called amount or cumulated or integrated exposure of analyte gases) rather than the actual analyte concentration. Therefore, gas dosimeters are especially suited for low level applications with the main interest on mean values. The applied materials are able to change their electrical properties by selective accumulation of analyte molecules in the sensitive layer. The accumulating or dosimeter-type sensing principle is a promising method for reliable, fast, and long-term detection of low analyte levels. In contrast to common gas sensors, few devices relying on the accumulation principle are described in the literature. Most of the dosimeter-type devices are optical, mass sensitive (quartz microbalance/QMB, surface acoustic wave/SAW), or field-effect transistors. The prevalent focus of this article is, however, on solid-state gas dosimeters that allow a direct readout by measuring the conductance or the impedance, which are both based on materials that change (selectively in ideal materials) their conductivity or dielectric properties with gas loading. This overview also includes different operation modes for the accumulative sensing principle and its unique features.

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Section: Suitable Materials For Accumulating Gas Sensorsmentioning

confidence: 99%

Overview on conductometric solid-state gas dosimeters

Marr

Groß²,

Moos

2014

J. Sens. Sens. Syst.

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“…The outlet concentrations were determined by a chemiluminescence detector, as illustrated in Figure 2. In accordance to the reported catalytic activity of Mn-containing LNTs [23,33–36], as well as to results on LNT-based NO x dosimeters [6,18], the NO x sorption studies were performed at a sorption temperature T sorption of 380 °C, with periodic heating to 650 °C for regeneration.…”

Section: Nox Sensing Propertiesmentioning

confidence: 91%

“…The decreased thermodynamic stability of the formed nitrates upon heating limits the catalytic activity of LNTs [38–40,49] and alters the cumulative NO x sensing characteristics of carbonates and LNT-based sensors [6,17,18,32]. According to Becerra et al[22], nitrate and nitrite-like compounds formed on KMnO 4 -based materials decompose in the temperature range of ∼550 to 670 °C.…”

Section: Nox Sensing Propertiesmentioning

confidence: 99%

“…Recently, impedimetric or resistive NO x dosimeters, based on materials utilized in automotive lean NO x trap catalysts (LNT), were successfully introduced [6,11,18]. Around 400 °C, these carbonate-based materials enable long-term detection of low levels of NO and NO 2 by monitoring the increase in conductivity with increased NO x loading.…”

Section: Introductionmentioning

confidence: 99%

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Dosimeter-Type NOx Sensing Properties of KMnO4 and Its Electrical Conductivity during Temperature Programmed Desorption

Groß

Kremling

Marr

et al. 2013

Sensors

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An impedimetric NOx dosimeter based on the NOx sorption material KMnO4 is proposed. In addition to its application as a low level NOx dosimeter, KMnO4 shows potential as a precious metal free lean NOx trap material (LNT) for NOx storage catalysts (NSC) enabling electrical in-situ diagnostics. With this dosimeter, low levels of NO and NO2 exposure can be detected electrically as instantaneous values at 380 °C by progressive NOx accumulation in the KMnO4 based sensitive layer. The linear NOx sensing characteristics are recovered periodically by heating to 650 °C or switching to rich atmospheres. Further insight into the NOx sorption-dependent conductivity of the KMnO4-based material is obtained by the novel eTPD method that combines electrical characterization with classical temperature programmed desorption (TPD). The NOx loading amount increases proportionally to the NOx exposure time at sorption temperature. The cumulated NOx exposure, as well as the corresponding NOx loading state, can be detected linearly by electrical means in two modes: (1) time-continuously during the sorption interval including NOx concentration information from the signal derivative or (2) during the short-term thermal NOx release.

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“…La determinación de la concentración de dichos contaminantes se puede realizar a través de la estimación mediante modelos de carácter físico (Andersson et al, 2006;Westlund and Åmströng, 2009;Schilling et al, 2006), o mediante la medida directa con un sensor (Kato et al, 1996;Smith, 2000;Geupel et al, 2011). Además, es posible combinar ambas señales mediante técnicas de fusión de datos (Faouzi et al, 2011;Khaleghi et al, 2013), con el fin de obtener una estimación que mantenga las virtudes de los modelos y los sensores.…”

Section: Introductionunclassified

Solución analítica de un filtro de Kalman estacionario para la observación de deriva en modelos de emisiones de NOx en motores diesel de automoción

Guardiola

Hoyas

Plá

et al. 2015

Revista Iberoamericana de Automática e Informática Industrial R

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An augmented state-space model for drift correction is proposed adding an extra-state for cancelling drift on a given model or sensor output. A Kalman filter is used for drift observation. The model is Linear Time Invariant and noise covariances are considered constant. Under these assumptions, filter is steadystate and an analytical solution to the Riccati equation can be derived. Current paper gives the analytical solution to the Kalman gain and covariance matrix from using the iterative filter equations.

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Integrating NO_x Sensor for Automotive Exhausts—A Novel Concept

Cited by 19 publications

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Overview on conductometric solid-state gas dosimeters

Overview on conductometric solid-state gas dosimeters

Dosimeter-Type NOx Sensing Properties of KMnO4 and Its Electrical Conductivity during Temperature Programmed Desorption

Solución analítica de un filtro de Kalman estacionario para la observación de deriva en modelos de emisiones de NOx en motores diesel de automoción

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Integrating NOx Sensor for Automotive Exhausts—A Novel Concept

Cited by 19 publications

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Overview on conductometric solid-state gas dosimeters

Overview on conductometric solid-state gas dosimeters

Dosimeter-Type NOx Sensing Properties of KMnO4 and Its Electrical Conductivity during Temperature Programmed Desorption

Solución analítica de un filtro de Kalman estacionario para la observación de deriva en modelos de emisiones de NOx en motores diesel de automoción

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Integrating NO_x Sensor for Automotive Exhausts—A Novel Concept