초록 ▼

Disclosed is an oxide sensor in which a measuring electrode is arranged at a distance d to satisfy -3t.ltoreq.d.ltoreq.3t for a downstream end of an inner pumping electrode for a first chamber, i.e., the end located on a side of a second diffusion rate-determining section, provided that d represents

Disclosed is an oxide sensor in which a measuring electrode is arranged at a distance d to satisfy -3t.ltoreq.d.ltoreq.3t for a downstream end of an inner pumping electrode for a first chamber, i.e., the end located on a side of a second diffusion rate-determining section, provided that d represents a distance between the measuring electrode and the downstream end in a positive direction directed from the first chamber to a second chamber, and t represents a height of the first chamber. A partial pressure of oxygen in the first chamber is measured by using the measuring electrode. A main pumping cell is subjected to feedback control on the basis of a measured value so that the partial pressure of oxygen in the first chamber is controlled. After that, a measurement gas is introduced into the second chamber. Oxides contained in the measurement gas are decomposed by the aid of a detecting electrode or a catalyst. A partial pressure of oxygen produced by the decomposition is measured to determine the concentration of the oxides. Accordingly, it is possible to measure the oxides contained in the measurement gas with an extremely high degree of accuracy. Moreover, the obtainable oxide sensor is compact and inexpensive.

대표청구항 ▼

[ What is claimed is:] [1.] An oxide sensor comprising:a main pumping means including a first solid electrolyte for contacting with external space, and inner and outer electrodes formed on inner and outer surfaces of the first solid electrolyte, for performing a pumping process for oxygen contained

[ What is claimed is:] [1.] An oxide sensor comprising:a main pumping means including a first solid electrolyte for contacting with external space, and inner and outer electrodes formed on inner and outer surfaces of the first solid electrolyte, for performing a pumping process for oxygen contained in a measurement gas introduced from said external space, on said basis of a control voltage applied between said electrodes;a concentration-measuring means including a second solid electrolyte, an inner measuring electrode formed on the second solid electrolyte on a side opposite to inner measuring electrode, for measuring an electromotive force of an oxygen concentration cell, generated corresponding to a difference in partial pressure between oxygen resulting from said pumping process performed by said main pumping means and oxygen contained in a gas existing on a side of said outer measuring electrode;a main pumping control means for adjusting a level of said control voltage so that said electromotive force of said oxygen concentration cell detected by said concentration-measuring means has a predetermined value; andan electric signal-generating conversion means including the second solid electrolyte and inner and outer detecting electrodes provide in contact with the second solid electrolyte, for providing, by conversion, an electric signal corresponding to an amount of oxygen contained in said measurement gas after being subjected to said pumping process performed by said main pumping means, wherein:said inner measuring electrode is arranged at a position at which -3t.ltoreq.d is satisfied provided that a downstream direction along a space for said pumping process performed by said main pumping means is defined as a positive direction, a height of said space for said pumping process is represented by t, and a protective distance between a downstream end of said inner pumping electrode of said main pumping means and a center of said inner measuring electrode of said concentration-measuring means is represented by d, and wherein:oxides in said measurement gas are measured on the basis of said electric signal supplied from said electric signal-generating conversion means.