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Catalysts as Sensors—A Promising Novel Approach in Automotive Exhaust Gas Aftertreatment
University of Bayreuth, Bayreuth Engine Research Center, Bayreuth, Germany
Received: 4 June 2010; in revised form: 7 July 2010 / Accepted: 9 July 2010 / Published: 13 July 2010
Abstract: Sensors that detect directly and in situ the status of automotive exhaust gas catalysts by monitoring the electrical properties of the catalyst coating itself are overviewed. Examples included in this review are the in-situ determination of the electrical impedance of three-way catalysts based on ceria-zirconia solutions and of lean NOx traps of earth-alkaline based coatings, as well as approaches to determine the ammonia loading in Fe-SCR-zeolites with electrical ac measurements. Even more sophisticated approaches based on interactions with electromagnetic waves are also reviewed. For that purpose, metallic stick-like antennas are inserted into the exhaust pipe. The catalyst properties are measured in a contactless manner, directly indicating the catalyst status. The radio frequency probes gauge the oxygen loading degree of three-way catalysts, the NOx-loading of lean NOx traps, and the soot loading of Diesel particulate filters
Keywords: on-board diagnosis (OBD); lambda probe; three-way catalyst (TWC); microwave; ammonia SCR; lean NOx trap (LNT)
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MDPI and ACS Style
Moos, R. Catalysts as Sensors—A Promising Novel Approach in Automotive Exhaust Gas Aftertreatment. Sensors 2010, 10, 6773-6787.
Moos R. Catalysts as Sensors—A Promising Novel Approach in Automotive Exhaust Gas Aftertreatment. Sensors. 2010; 10(7):6773-6787.
Moos, Ralf. 2010. "Catalysts as Sensors—A Promising Novel Approach in Automotive Exhaust Gas Aftertreatment." Sensors 10, no. 7: 6773-6787.