Robert Boschgmbh

Frank Molwitz

Erich Junginger

Rene Schenk

Christian Zimmermann

Johann Riegel

Bernd Hilgenberg

Dietmar Blessing

Wilhelm Haag

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 R() of an electrochemical cell () 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 () is applied to the internal resistance R() of the electrochemical cell () and a resulting first voltage is detected. A switchover to a reference resistor Rtakes place from time to time or at regular time intervals. With a switchover to the reference resistor R, the resulting second voltage is stored and thereafter is applied as a reference value for the measurement of the internal resistance R(). The switchover () to the reference resistor Rtakes place, for example, via force/sense lines.

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

Growing community of inventors

Kornwestheim, Germany

Frank Molwitz