| 摘要 |
PURPOSE: To measure the NOx concentration accurately by exposing first and second electrodes, where different decomposed state of NOx takes place, to a test gas and then measuring the electrical difference between two electrodes. CONSTITUTION: A sensor body section 10 forms first and second chambers 11, 12 partitioned by a wall 13. First and second electrodes 14, 15 are fixed to the opposite sides of the wall 13 in respective chambers 11, 12. A mixture gas containing NOx is introduced through individual holes 16, 17 into respective chambers 11, 12 and the NOx is decomposed into nitrogen and oxygen at respective electrodes. The first electrode 14 is larger than the second electrode 15. Since the activity of oxygen is not identical at each electrode, a potential difference or an electromotive force appears between the first and second electrodes 14, 15. The potential difference is measured by means of a voltage measuring device 18 and the NOx concentration is determined based on the potential difference. |
