B7.1 - RF-probing of Automotive Catalysts
- SENSOR+TEST Conferences 2009
2009-05-26 - 2009-05-28
Congress Center Nürnberg
- Proceedings SENSOR 2009, Volume II
- B7 - Gas and Humidity
- S. Reiss, R. Moos, M. Wedemann, M. Spoerl, A. Nerowski, G. Fischerauer - Universität Bayreuth, Bayreuth, Germany
- 113 - 116
In order to meet the strict emission regulations, gasoline operated vehicles are equipped with three-way catalysts (TWC) and lambda sensors are applied to control the exhaust gas aftertreatment system. Since the TWC achieves maximum conversion of hydrocarbons, carbon monoxide, and nitrogen oxides at λ ≈ 1, λ is measured by lambda-probes upstream and downstream of the catalyst and is readjusted if required (λ: normalized air-to-fuel ratio). This leads to an oscillating air-to-fuel-ratio that is damped by oxygen storage components in the washcoat of the TWC (ceria-zirconia mixed oxides). These ceria-based materials store oxygen under lean atmospheres (λ > 1) and release oxygen under rich conditions (λ < 1).
In the present contribution, aspects of a novel approach to determine the oxygen loading of a TWC by a contactless measurement and in-situ with the help of radio frequency (RF) without lambda-probes is presented.