Electro-chemical sensor

US4021326A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Rudolf Pollner
• Karl-Hermann Friese · Leonberg, DE
• Bernhard Topp · Gerlingen, DE
• Horst Neidhard

Key dates

• Filing date: Mar 4, 1974
• Grant date: May 3, 1977
• Expiry date: Mar 4, 1994

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N27/4077
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Electro-chemical sensor to determine oxygen concentration in hot internal combustion exhaust gases in the form of a closed, tubular element having a solid ion conductive electrolyte; an electron-conductive coating on the inner surface thereof; a porous or fissured electron conductive layer on the outer surface of said solid electrolyte or on a part of said surface, part of the pores or fissures being macroporous, said layer being of a material which catalyzes the formation from said hot exhaust gases of those compounds that are thermodynamically stable at the exhaust temperature; and a porous protective electrically insulating coating on said porous electron-conductive layer. Preferably, a top coating of a heat-resistant metal is applied, which top coating has additionally properties to act as a getter with respect to poisons affecting the catalyzing material.