Gas sensor construction, particularly to determine oxygen content combustion exhaust gases, particularly from internal combustion engines

US4305803A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Barbara Beyer · Stuttgart, DE
• Hermann Dietz · Gerlingen, DE
• Karl-Hermann Friese · Leonberg, DE

Key dates

• Filing date: Sep 4, 1980
• Grant date: Dec 15, 1981
• Expiry date: Sep 4, 2000

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N27/4071
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

To facilitate manufacture of a sensor, particularly a polarographic sensor which has no sealing or heat expansion difficulties and only low heat capacity in the measuring range and electrical connections, a solid electrolyte (17) is formed as a plate extending transversely across a bottom opening (13) of a preferably ceramic tube (11), the plate having two electrodes (16,21) applied to its major sides. The side facing the opening (13) is covered with a ceramic layer (20) having a predetermined diffusion or migration resistance to oxygen molecules. The electrical connections are formed by a conductive track (15) extending on the inside of the ceramic tube, in contact with the sensing electrode on one side of the plate; and a counter head (23) connected to a conductive bolt or pin (24) and resiliently spring pressed against the electrode, and holding the plate (17) and the diffusion barrier (20) thereon in position in the sensor. The test gas is applied to the diffusion resistance layer through a ceramic heat storage plate, for instance, having openings therethrough, which has a film-type heater applied thereto, connected to a current source by conductive tracks (31, 31'; 32, 32') po…