The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 21, 1998
Filed:
Aug. 04, 1997
Eleftherios Miltiadis Logothetis, Birmingham, MI (US);
Richard E Soltis, Saline, MI (US);
Ford Global Technologies, Inc., Dearborn, MI (US);
Abstract
The invention is a sensing method and an oxygen sensor for detecting a change of oxygen partial pressure in an ambient atmosphere. The sensor includes a sensing material selected from metal or its oxides which, when at an elevated temperature and exposed to a gas containing a changing partial pressures of oxygen, is capable of changing from one metal or metal oxide phase to another such oxide phase and vice versa. Associated with such phase change is a change in a measurable physical property of the material. Heating elements, connectable to a power source, able to maintain a temperature gradient across said sensing material are necessary to maintain the material, during active sensing operation, in at least two of the phases defining a boundary line therebetween which is generally perpendicular to the longitudinal axis of the temperature gradient. The boundary line traverses longitudinally along the axis in response to changes in the oxygen partial pressure of the ambient atmosphere to which the sensing material is exposed. The sensor also includes a device for furnishing an output signal in response to the traversal of the boundary line across a fixed detecting location of the sensing material. Hence, the invention senses the passage of the boundary line at some specific location in the material to detect a specific P.sub.02,c.