| 摘要 |
The invention relates to a method for operating a sensor for determining the concentration of oxidizing gases in gas mixtures, especially the nitrous oxide concentration of exhaust gases emitted by an internal combustion engine. Said sensor comprises at least one chamber (1,2) which is arranged in a solid electrolyte (20) and connected via a first diffusion barrier (49) to a gas mixture; and a second chamber (3) which is arranged in a solid electrolyte (20) and has a predefinable constant partial oxygen pressure. An oxygen pump electrode (9) exposed to the exhaust gas is arranged on the solid electrolyte (20). One further oxygen pump electrode (7; 8) and one NO-pump electrode (10) are arranged in the at least one chamber (1; 2). An oxygen reference electrode (6) is arranged in the second chamber (3). At least one voltage is applied to the electrodes and at least one pump stream is evaluated as a measuring signal. The invention is characterized in that the voltages (U-IPE; U-02, U-NO) applied to the electrodes (U-IPE; U-02, U-NO) are altered according to the currents flowing through the electrode leads and/or between the electrodes (6; 7; 8; 9; 10) during operation of the sensor, whereby the voltages applied to electrodes (6; 7; 8; 9; 10) on the inside of the sensor correspond to predefinable setpoint values.
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