VERFAHREN ZUR ERZEUGUNG EINES REFERENZPOTENTIALS BEI POTENTIOMETRISCHEN LAMBDASONDEN

摘要

In said method, the measuring electrode and the counter-electrode are exposed to exhaust gas and present an adjustment which causes alternating changes between the rich and lean operations. Furthermore the counter-electrode is so arranged that the sensitive time and the dead time upon the passage of gas from the rich to the lean operation deviate from the sensitive time and the dead time upon the gas passage from the lean to the rich operation. Therefore, the counter-electrode has asymmetric sensitive times. A rich reference is preferably used wherein the sensitive time and the dead time upon the gas passage from the lean to the rich is shorter than the passage from the rich to the lean. Furthermore, the counter-electrode is provided with an anti-diffusion layer which presents pores having diameters which are small with respect to the mean free travelling length of oxygen molecules. Thereby, the measuring electrode does not make loop oscillations in the rich to lean direction and generate a substantially constant potential which may be used as a reference potential for the probe.