Measuring sensor for determining the oxygen content in gas mixtures

US5686654A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Karl-Hermann Friese · Leonberg, DE
• Werner Gruenwald · Gerlingen, DE

Key dates

• Filing date: Aug 8, 1996
• Grant date: Nov 11, 1997
• Expiry date: Aug 8, 2016

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N27/419
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A measuring sensor for determining the oxygen content in gas mixtures including exhaust gases of internal combustion engines, includes a first electrochemical pump cell and a second electrochemical pump cell; an internal reference gas source; a measuring gas chamber which is connected to the gas mixture; electrodes for the first and the second pump cell; a first pumping voltage (U.sub.P1) for the first pump cell and a second pumping voltage (U.sub.P2) for the second pump cell; wherein oxygen is pumped into the internal reference gas source by means of the first pumping voltage, wherein a pumping current is driven by the second pumping voltage and is measured as a measure for the partial oxygen pressure, wherein the first pumping voltage (U.sub.P1) and the second pumping voltage (U.sub.P2) are set such that more oxygen is pumped into the reference gas source by way of the first pumping voltage (U.sub.P1) than is pumped out of the reference gas source by the second pumping voltage (U.sub.P2), and wherein the first pump cell is acted upon by a first operating voltage (U.sub.B1) and the second pump cell is acted upon by a second operating voltage (U.sub.B2) so that, under the action of…