Electrochemical oxygen sensor, particularly for exhaust gases from combustion engines

US4437971A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Herbert Csanitz · Bietigheim-Bissingen, DE
• Helmut Weyl

Key dates

• Filing date: Jun 19, 1981
• Grant date: Mar 20, 1984
• Expiry date: Jun 19, 2001

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N27/4067
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

To prevent signal degradation of a sensing element, which may be a potentiometric or a polarographic sensor, having a reference electrode exposed to ambient air, the reference electrode (22) is placed within a chamber (21) which has included therein granules (39) of a material inert with respect to oxygen and having a surface hardness at least as hard as the reference electrode (22) so that, upon subjection of the sensor, when coupled to the exhaust system of an internal combustion engine, to vibrations, shocks and jolts, the granules will move in the chamber, rub against the electrode, and hence keep the electrode surface activated and free from contamination which may have penetrated with ambient air.