Oxygen content exhaust gas sensor, and method of its manufacture

US4347113A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Hermann Fischer · Augsburg, DE
• Karl-Hermann Friese · Leonberg, DE
• Hans-Ulrich Gruber · Gerlingen, DE
• Wolfgang Heinemann · Remscheid, DE
• Gunter Knoll · Büttelborn, DE
• Ernst Linder · Mühlacker, DE
• Helmut Maurer · Rodenbach, DE
• Rainer Noack · Bietigheim, DE
• Leo Steinke · Waiblingen, DE
• Lothar Weber · Stuttgart, DE
• Helmut Weyl

Key dates

• Filing date: Mar 25, 1980
• Grant date: Aug 31, 1982
• Expiry date: Mar 25, 2000

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P70/50
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

To improve operation and output voltage, particularly at 400.degree. C. and less, an oxygen sensor, especially adapted to determine oxygen content of automotive exhaust gases, is constructed by utilizing two electrodes applied on a body of stabilized zirconium dioxide, for example a closed tube, by making an electrode exposed to the exhaust gases in form of a mixture of finely dispersed ceramic material and a platinum-rhodium alloy, the ceramic material being present at about 40% (by volume) and 60% (by volume) platinum-rhodium alloy of 50-94% platinum and 50-6% rhodium (by weight). The second electrode, exposed to a reference gas comprises an alloy of palladium and another noble metal in a ratio of about 19-90% (by weight) Pd and 81-10% (by weight) noble metal. This electrode may also contain up to 40% (by volume) finely dispersed ceramic material. The electrode exposed to the exhaust gases is covered with a porous coating. The electrodes can be applied as aqueous or organic solutions of soluble noble metal compounds or suspensions, colloidal suspensions, with organic solvents, and the like, and subsequent sintering.