Concept of a Multi-Gas Sensor to Meet the Strictest Emission Requirements for Combustion Engines

Authors

J. Herrmann MSc, Dr.-Ing. G. Hagen, Dr.-Ing. J. Kita, Prof. Dr.-Ing. R. Moos, University of Bayreuth; Dipl.-Ing. D. Bleicker, Dipl.-Ing. F. Noack, CPK Automotive GmbH & Co. KG, Münster:

Year

2021

Print Info

Production/Publication ÖVK

Summary

Due to strict emission limits for nitrogen oxides in the field of combustion engines, there are various concepts for exhaust gas aftertreatment. All require robust sensors for monitoring and control. In addition to commercially available zirconia-based sensors, a new impedancebased NO_x sensor is developed. The sensor is fabricated using planar thick film technique, where a NO_x-sensitive functional material is deposited on screen-printed interdigital electrodes. Since the NO_x signal of the sensor depends on the λ-value of the surrounding gas, an O₂-sensitive functional layer is integrated on the sensor substrate additionally. It can be shown that both functional layers can be operated individually as well as simultaneously without affecting each other. By recording NO-dependent and O₂-dependent characteristic curves, the O₂-sensitive functional layer can be used to correct the λ-dependent NO_x signal and convert it into a NO_x concentration. In further optimization of the sensor, a new heater layer structure was developed, which allows for more accurate temperature control of the functional layers. In addition, a protective cap for this sensor application was designed by means of flow simulation.

Number of pages

11 Order