Sensor element for an oxygen limiting current probe in order to determine the .lambda. value of gas mixtures

US5302275A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Hermann Dietz · Gerlingen, DE
• Barbara Beyer · Stuttgart, DE
• Werner Gruenwald · Gerlingen, DE
• Claudio Da La Prieta · Stuttgart, DE

Key dates

• Filing date: Sep 14, 1992
• Grant date: Apr 12, 1994
• Expiry date: Sep 14, 2012

Classification

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

Abstract

A sensor element is proposed for an oxygen limiting current probe for the determination of the .lambda. value of gas mixtures, particularly the exhaust gases of internal-combustion engines, whose oxygen supply is provided by a short-circuit cell disposed upstream of the pumping cell of the sensor element. In this way the CO.sub.2 and H.sub.2 O transverse sensitivity of the sensor element is made ineffective. In order to obtain at the pumping cell a limiting current that is a linear function of the O.sub.2 partial pressure, a diffusion barrier must additionally be disposed between the short-circuit cell and the pumping cell.