Recent Developments in the Field of Automotive Exhaust Gas Ammonia Sensing

Moos, Ralf; Schönauer-Kamin, Daniela

doi:10.1166/sl.2008.509

Cited by 35 publications

(17 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It allows the closed-loop control of the SCR-system and also the OBD of the SCR-catalyst. Different NH 3 sensing principles have been investigated for that purpose [5]. Solid electrolyte-based sensors with optimized electrode materials and configurations seem most promising.…”

Section: Introductionmentioning

confidence: 99%

Half-Cell Potential Analysis of an Ammonia Sensor with the Electrochemical Cell Au | YSZ | Au, V2O5-WO3-TiO2

Schönauer-Kamin

Fleischer

Moos

2013

Sensors

Self Cite

View full text Add to dashboard Cite

Half-cell potentials of the electrochemical cell Au, VWT | YSZ | Au are analyzed in dependence on oxygen and ammonia concentration at 550 °C. One of the gold electrodes is covered with a porous SCR catalyst, vanadia-tungstenia-titania (VWT). The cell is utilized as a potentiometric ammonia gas sensor and provides a semi-logarithmic characteristic curve with a high NH3 sensitivity and selectivity. The analyses of the Au | YSZ and Au, VWT | YSZ half-cells are conducted to describe the non-equilibrium behavior of the sensor device in light of mixed potential theory. Both electrode potentials provide a dependency on the NH3 concentration, whereby VWT, Au | YSZ shows a stronger effect which increases with increasing VWT coverage. The potential shifts in the anodic direction confirm the formation of mixed potentials at both electrodes resulting from electrochemical reactions of O2 and NH3 at the three-phase boundary. Polarization curves indicate Butler-Volmer-type kinetics. Modified polarization curves of the VWT covered electrode show an enhanced anodic reaction and an almost unaltered cathodic reaction. The NH3 dependency is dominated by the VWT coverage and it turns out that the catalytic properties of the VWT thick film are responsible for the electrode potential shift.

show abstract

Section: Introductionmentioning

confidence: 99%

Half-Cell Potential Analysis of an Ammonia Sensor with the Electrochemical Cell Au | YSZ | Au, V2O5-WO3-TiO2

Schönauer-Kamin

Fleischer

Moos

2013

Sensors

Self Cite

View full text Add to dashboard Cite

show abstract

“…Different principles for ammonia sensing in the exhaust are reviewed in the literature [10]. On the one hand, the existing pronounced NH 3 cross-sensitivity of the planar zirconia-based amperometric NO x sensor as described in Ref.…”

Section: Introductionmentioning

confidence: 99%

Selective mixed potential ammonia exhaust gas sensor

Schönauer

Wiesner

Fleischer

et al. 2009

Sensors and Actuators B: Chemical

Self Cite

111

View full text Add to dashboard Cite

“…Many efforts were being made in the past years to develop novel automotive exhaust gas sensors that are sensitive, selective, long-term stable, and cost effective (Riegel et al, 2002;Moos, 2005;Alkemade and Schumann, 2006;Zhuiykov and Miura, 2007;Fergus, 2007;Moos and Scho¨nauer, 2008). However, per today, only sensors based on yttria stabilized zirconia like the binary lambda probe, the wide-band lambda probe (also Universal Exhaust Gas Oxygen sensor, UEGO sensor, or linear lambda probe), and the amperometric NO x sensor have been serialized.…”

Section: Exhaust Gas Sensorsmentioning

confidence: 99%

Automotive Catalyst State Diagnosis Using Microwaves

Moos

Fischerauer

2014

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

Self Cite

View full text Add to dashboard Cite

-The state of catalysts plays a key role in automotive exhaust gas aftertreatment. The soot or ash loading of Diesel particulate filters, the oxygen loading degree in three-way catalysts, the amount of stored ammonia in SCR catalysts, or the NO x loading degree in NO x storage catalysts are important parameters that are today determined indirectly and in a model-based manner with gas sensors installed upstream and/or downstream of the catalysts. This contribution gives an overview on a novel approach to determine the catalyst state directly by a microwave-based technique. The method exploits the fact that the catalyst housing acts as a microwave cavity resonator. As "sensing" elements, one or two simple antennas are mounted inside the catalyst canning. The electrical properties of the catalyst device (ceramic honeycomb plus coating and storage material) can be measured. Preferably, the resonance characteristics, e.g., the resonance frequencies, of selected cavity modes are observed. The information on the catalyst interior obtained in such a contactless manner is very well correlated with the catalyst state as will be demonstrated for different exhaust gas aftertreatment systems.Re´sume´-Diagnostic de l'e´tat de catalyseurs d'automobiles a`l'aide de micro-ondes -L'e´tat des catalyseurs joue un roˆle essentiel dans le post-traitement des gaz d'e´chappement automobiles. Le chargement en suie ou en cendres des filtres Diesel a`particules, la teneur en oxyge`ne dans les catalyseurs trois voies, la quantite´d'ammoniac stocke´e dans les catalyseurs SCR ou le niveau de chargement en NO x dans les catalyseurs de stockage de NO x sont des parame`tres importants de´termine´s aujourd'hui de manie`re indirecte et sur la base de mode`les avec des capteurs de gaz se trouvant en amont et/ou en aval des catalyseurs. Cette contribution pre´sente une nouvelle approche permettant de de´terminer l'e´tat du catalyseur, directement en utilisant une technique a`micro-ondes. La me´thode exploite le fait que le boıˆtier du catalyseur agit comme cavite´re´sonnante de micro-ondes. En tant qu'e´le´ments de de´tection, une ou deux antennes simples sont installe´es a`l'inte´rieur du conditionnement du catalyseur. Les proprie´te´s e´lectriques du dispositif catalytique (nid d'abeille en ce´ramique plus reveˆtement et mate´riau de stockage) peuvent eˆtre mesure´es. De pre´fe´rence, les caracte´ristiques de re´sonnance, par exemple les fre´quences de re´sonnance, des modes de cavite´se´lectionne´s, sont observe´es. Les donne´es obtenues de cette manie`re sans contact, sont tre`s bien corre´le´es avec l'e´tat du catalyseur, tel que cela sera de´montre´pour diffe´rents syste`mes de post-traitement des gaz d'e´chappement.

show abstract

Recent Developments in the Field of Automotive Exhaust Gas Ammonia Sensing

Cited by 35 publications

References 0 publications

Half-Cell Potential Analysis of an Ammonia Sensor with the Electrochemical Cell Au | YSZ | Au, V2O5-WO3-TiO2

Half-Cell Potential Analysis of an Ammonia Sensor with the Electrochemical Cell Au | YSZ | Au, V2O5-WO3-TiO2

Selective mixed potential ammonia exhaust gas sensor

Automotive Catalyst State Diagnosis Using Microwaves

Contact Info

Product

Resources

About