Conductometric Soot Sensor for Automotive Exhausts: Initial Studies

Hagen, Gunter; Feistkorn, Constanze; Wiegärtner, Sven; Heinrich, Andreas; Brüggemann, Dieter; Moos, Ralf

doi:10.3390/s100301589

Cited by 46 publications

(34 citation statements)

References 20 publications

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“…Since soot loading in DPF increases the filter conductivity by orders of magnitude (Hagen et al, 2010), one observes effects as great as in TWC. In order to suppress the possible influence of soot deposition at the coupling antenna, one may use a single waveguide feed located downstream of the DPF where the exhaust is almost soot-free.…”

Section: Application To Dpf Soot Loading Determinationmentioning

confidence: 99%

Automotive Catalyst State Diagnosis Using Microwaves

Moos

Fischerauer

2014

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

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-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.

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Section: Application To Dpf Soot Loading Determinationmentioning

confidence: 99%

Automotive Catalyst State Diagnosis Using Microwaves

Moos

Fischerauer

2014

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

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“…al. showed a resistance-based approach was a feasible method to detect soot in the exhaust of a diesel engine due to failures in the engine's particulate filter [11]. Hagen screen printed gold conductive tracks on a ceramic substrate and measured the electrical resistance between tracks.…”

Section: Prior Workmentioning

confidence: 99%

“…Researchers have previously printed gold and platinum onto ceramic substrates [11]. The use of a metallic conductor would reduce the resistance of the electrical connections in the Wheatstone bridge circuit and eliminate the temperature dependent conductivity of SLT.…”

Section: Future Workmentioning

confidence: 99%

Development of an impedance-based sensor for detection of catalyst coking in fuel reforming systems

Wheeler

2013

Sensors and Actuators B: Chemical

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A novel sensor for detecting the early stages of catalyst coking in fuel reforming systems has been developed. The sensor was manufactured by inkjet printing a colloidal suspension of ceramic powders to create thin (20 µm) catalytic and conductive elements of the sensor.The catalytic elements are composed of a Ni-YSZ cermet. The Ni-YSZ cermet was prepared with a concentration below the percolation limit (20 vol%) of nickel, ensuring a low electrical conductivity. As coke forms on the catalyst material, the nickel nodules in the Ni-YSZ are connected by electrically conductive carbon and the conductivity of the catalyst material increases, indicating coke formation.Sensors were tested in a 1% ethylene environment to induce coking. The sensor showed a strong response to coking by producing a signal on the order of hundreds of millivolts.

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“…(3,7,8) For this reason, several soot detection technologies have been proposed by researchers in the last few decades. Potentiometric and amperometric soot sensors based on an oxide ion conductor (zirconia) and electrical insulator were proposed by Vogel and colleagues (8,9) and Moss and colleagues, (10)(11)(12) and these can be used for in situ measurements of soot concentration. Sensors based on the electromagnetic wave method, which includes radio-frequency (RF) (13,14) and optical waves in terms of changing the light transmission, scattering or extinction, have also been used to monitor PM concentration.…”

Section: Introductionmentioning

confidence: 99%

Sensing of Soot Oxidation by Using Combustion-Type Sensor with Ag-Supported Catalyst

2016

Sensors and Materials

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Soot-sensing properties of the combustion-type sensor coated with Ag-supported catalysts (Ag/TiO 2 , Ag/α-Al 2 O 3 , and Ag/CeO 2 ) were investigated. The catalyst with a high carbon black (CB) oxidation activity in the tight contact (TC) mode had a high response speed, although the response speed had no relationship with the CB oxidation activity in the loose contact (LC) mode. Moreover, the difference in CB oxidation activities between TC and LC modes was consistent with the difference in response speed between V 10 and V 50 , where V 10 and V 50 indicate the response speed of the CB oxidation at 10 and 50% of total output voltage. The catalyst with high intrinsic CB combustion activity improves the response property at initial combustion. On the other hand, the catalyst with the CB combustion activity, which does not depend on the contact state between the CB and the catalyst, improves the response property at later combustion.

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Conductometric Soot Sensor for Automotive Exhausts: Initial Studies

Cited by 46 publications

References 20 publications

Automotive Catalyst State Diagnosis Using Microwaves

Automotive Catalyst State Diagnosis Using Microwaves

Development of an impedance-based sensor for detection of catalyst coking in fuel reforming systems

Sensing of Soot Oxidation by Using Combustion-Type Sensor with Ag-Supported Catalyst

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