Patent ID: 6551499
Filing Date: 2003-04-22
Classification: G01N

Abstract:
A method for monitoring the function and/or regeneration of a gas probe, the gas probe including: a heatable probe ceramic which detects gas molecules, a first pump electrode arranged in a chamber, and a second pump electrode arranged in the exhaust gas of the engine, the method comprising the steps of:a) providing a pump voltage source and applying a pump voltage across the first and second pump electrodes so that an oxygen partial pressure is adjusted in the interior of said chamber by electrochemically pumping away the oxygen molecules; b) applying a first pump voltage and measuring a first pump current; c) applying a second pump voltage, which is higher or lower compared to the first pump voltage, and measuring a second pump current; d) forming the difference (&Dgr;I) of the first and second pump currents; e) if the difference (&Dgr;I) exceeds a pregiven value, applying a previously determined saturation pump voltage and comparing a resulting pump current to a previously stored minimum pump current; f) forming the difference of the minimum pump current and of the resulting pump current (&Dgr;I plus); and g) if the difference (&Dgr;I plus) of the minimum pump current and of the resulting pump current exceeds a pregiven amount, applying a regeneration voltage, wherein the is generated by a further pump source, which regeneration voltage is greater than the saturation voltage.