| 摘要 |
<p>A NOx sensor comprises a first internal space (6) into which the measurement gas is introduced through a first diffusion rate-determining passage (12), a second internal space (8) arranged with a NOx-reducing catalyst, into which an atmosphere is introduced through a second diffusion rate-determining passage (14), an electrochemical pumping cell for controlling a partial pressure of oxygen in the internal space (6). A first electrochemical sensor cell for outputting an electromotive force corresponding to the partial pressure of oxygen in the internal space (8), and a voltage-detecting means (32) for detecting the electromotive force outputted from the first electrochemical sensor cell are provided. The NOx concentration is determined from a value of the electromotive force of the first electrochemical sensor cell detected by the voltage-detecting means (32). <IMAGE></p> |
