| 摘要 |
PURPOSE: To calculate a precise NOX concentration by providing a pair of electrodes opposite to each other on an electrolyte to form a sensor element, and measuring the impedance between the electrode. CONSTITUTION: A paste obtained by mixing platinum and Ba2 YCu3 O7 by calculated moles is screen-printed on one surface of a solid electrolytic substrate 1 about 3.5mm thick consisting of a stabilized zirconia having 8 mole % of yttria added thereto to form an electrode 2. The same paste is printed on the other surface to form an electrode 3 followed by baking in an electric furnace, and a current is further carried to thermally treat it. An impedance measuring instrument 4 and an arithmetic means 5 are connected to the resulting sensor element to form a NOX sensor. The impedance is measured by the measuring instrument 4, the val 7 resistance and the electrode resistance are determined by the means 5. The temperature can be determined from the val 7 resistance, and the NOX concentration can be determined from the temperature and the electrode resistance. Thus, even when the operating temperature of the sensor is fluctuated, a precise NOX concentration can be determined. |
