HC-sensor for exhaust gases based on semiconducting doped SrTiO sub(3) for On- Board Diagnosis

In this contribution, a multilayer resistive sensor based on catalytically activated and non-activated SrTiO sub(3) is presented as a device for lean hydrocarbon sensing. This set-up should enable a compensation of oxygen cross interference. Whereas the catalytically activated part merely detects a variation in the oxygen equilibrium concentration in presence of hydrocarbons, the non-activated part strongly interacts with the reducing gases. Promising results with respect to stable sensor signals covering a wide hydrocarbon concentration range have been obtained using ethane and propane as hydrocarbon species. The sensor response is found to depend on the chain length of the used hydrocarbons. Using both sensor signals, an evaluation method for oxygen compensation has been studied. In addition, the cross interference of other common exhaust components has been investigated.