| 摘要 |
PURPOSE:To allow the use of the sensor in a broad concn. range of a detected O2 concn. and output current characteristic by detecting and correcting the abnormal output current at the time of the low O2 concn. which entails an imperfect combustion. CONSTITUTION:This sensor 1 is constituted by providing electrodes 22, 23 on both sides of a solid electrolyte body 21 consisting of ZrO2 and disposing a diffusion resistance layer 24 on one thereof. Both sides are brought into contact with the same gas. This sensor 1 is disposed in the position where the oxygen component in an exhaust gas 16 is to be detected and the sensor is connected to an amplifier circuit body 5 in the case of a gas combustion apparatus. The operation of the sensor 1 is controlled by a sensor amplifier circuit body 11 of this circuit body 5. Namely, positive and negative voltages are alternately impressed between the electrodes 22 and 23. The presence or absence of the abnormal output based on the imperfect combustion is discriminated by comparison with a reference current in the stage of the impression of the above-mentioned negative voltage. The oxygen concn. is measured by detecting the output current in the stage of the impression of the positive voltage. The detected current is corrected to 0, etc., when the abnormal output is detected. A malfunction is thus prevented and the expansion of the range of the O2 concn. to be detected is possible. |
