Sensing Catalytic Converters and Filters at Work Using Radio Frequencies

Abstract

The state of catalysts and filters plays a key role in automotive exhaust gas aftertreatment. The soot or ash loading of particulate filters (GPF or DPF), the oxygen loading of three-way catalysts (TWC), the amount of stored ammonia in SCR catalysts, or the NOx loading degree in NOx storage catalysts (NSC) are important parameters. Today, they are determined indirectly based on models that are calibrated by gas or pressure sensors in the exhaust pipe. This contribution overviews a novel approach that determines directly the state of the devices by a radio frequency based technique. For that purpose, the housing of the devices serves as a cavity resonator. As “sensing” element, one or two simple antennas are mounted in the catalyst canning. This contactless-obtained information correlates very well with the catalyst or filter state.

Investigations of the Usefulness of Dilatometric Methods in the Diagnostics of Combustion Engines

“…Components of this system are used in many areas of internal combustion engine operation. These include misfire monitoring [1,2], diesel particulate filter monitoring [3][4][5][6], catalyst monitoring [7,8], fuel system monitoring [9,10], and EGR system monitoring [11][12][13]. The common features of these systems are that they supervise the operation of the electronic control systems, and that their operation aims to control engine operation in order to meet ecological requirements.…”