Novel sensors for monitoring high oxygen concentrations

Using a novel approach, an oxygen sensor for monitoring high concentrations has been developed. The technique consists of applying a potential to an o xygen conducting solid electrolyte in one direction and the current measure d, the potential reversed and the current re-measured, to obtain a current ratio which strongly and linearly depends on % oxygen in the high concentra tions. Complications such as pinhole or porous diffusion barrier for limiti ng current are not required in this approach. Furthermore, by choosing appr opriate values of the applied potential, it is possible to obtain extremely high sensitivity at any predetermined oxygen concentrations. Using this co ncept, it is possible to use a standard solid electrolyte oxygen sensor for application in automotive engines and other combustion systems. (C) 1999 E lsevier Science B.V. All rights reserved.