A high temperature O2 sensor is described based on electrochemical pumping with a ceramic structure incorporating two ZrO2 O2 concentration cells. Two modes of operation, steady state and oscillatory, are described. In each case at least a linear sensitivity to ambient O2 concentration can be achieved. A potential application is that of exhaust-gas O2 sensing for the feedback control of intake air-to-fuel ratios at values lean of stoichiometry.
