Sensor element for limiting-current sensors for determining the lambda value of gas mixtures

US6375816B1 · kind B1 · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Olaf Jach · Eppelheim, DE
• Harald Neumann · Lambach, DE
• Lothar Diehl · Stuttgart, DE

Key dates

• Filing date: Dec 14, 1999
• Grant date: Apr 23, 2002
• Expiry date: Dec 14, 2019

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N27/4072
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A sensor element for limiting-current sensors for determining the lambda value of gas mixtures, in particular of exhaust gases from internal combustion engines. The sensor element has inner and outer pump electrodes arranged on a solid electrolyte foil. The inner pump electrode is arranged in a diffusion channel that is bordered by a diffusion barrier, the pump electrode lying in the diffusion direction of the gas mixture downstream of the diffusion barrier. The gas entry hole, essentially perpendicular to the surface of the solid electrolyte foil, is led through the solid electrolyte foil into the diffusion channel. The diffusion barrier is arranged so as to be set back in the diffusion channel from the interior wall of the gas entry hole. For manufacturing the sensor element, a chamber created upstream of the diffusion barrier is filled with a cavity-creating material, which evaporates in the sintering of the sensor element and thus forms a cavity in the diffusion channel.