| 摘要 |
<p>The sensor has an electrical heating unit for heating the sensing element to a temperature Tsoll, and has an applied oxygen pump voltage Vp0. To ensure that the applied pump voltage Vp0 does not exceed a maximum value above which premature decomposition of NOx would occur, the operating temperature of the sensor is slowly increased in steps over its operating life. The pump voltage Vp0 is compared at VGL with a maximum value Vp0max, and, if that voltage is exceeded, switching unit SE is operated to incrementally increase the temperature value Tsoll by an amount K(Vp0max-Vp0), (K being a correction factor), so that the electrical resistance R given by the ratio of pump voltage Vp0 to oxygen ion pump current Ip0 is reduced.</p> |
