Determining the temperature of an exhaust gas sensor by means of calibrated internal resistance measurement

US6939037B2 · kind B2 · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Erich Junginger · Stuttgart, DE
• Dietmar Blessing · Holzgerlingen, DE
• Christian Zimmermann · Erlangen, DE
• Wilhelm Haag · Reutlingen, DE
• Frank Molwitz · Kornwestheim, DE
• Rene Schenk · Tamm, DE
• Bernd Hilgenberg · Reutlingen, DE
• Johann Riegel · Bietigheim-Bissingen, DE

Key dates

• Filing date: Jul 6, 2002
• Grant date: Sep 6, 2005
• Expiry date: Jul 6, 2022

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F02D41/1496
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

For achieving a highest possible measuring accuracy of a circuit for measuring the internal resistance of an exhaust-gas sensor, a method and a circuit for measuring the internal resistance R1 (10) of an electrochemical cell (12) are provided for determining the temperature of an exhaust-gas sensor, especially of a motor vehicle. The circuit is provided with the objective to improve the control to a constant temperature to therefore also improve the performance of the exhaust-gas sensor. A measurement current I_Mess (20) is applied to the internal resistance R1 (10) of the electrochemical cell (12) and a resulting first voltage is detected. A switchover to a reference resistor R2 takes place from time to time or at regular time intervals. With a switchover to the reference resistor R2, the resulting second voltage is stored and thereafter is applied as a reference value for the measurement of the internal resistance R1 (10). The switchover (18) to the reference resistor R2 takes place, for example, via force/sense lines.