| 摘要 |
PURPOSE:To prevent the deterioration and the decrease in sensitivity by using a material such as sintered titanium oxide body wherein electrical conduction is accomplished partly by ion conduction as an oxygen sensor, and setting the voltage acting upon this oxygen sensor at less than the specific value. CONSTITUTION:A DC power source 1 (for example, 5V), an oxygen sensor 2 formed with a platinum electrode on a porous sintered titania disc of about 1-5mm. diameters and 1-3mm. thicknesses and a reference resistance 3 having a 10KOMEGA resistance value are connected in series, thereby forming a closed circuit. Further, a Zener diode 4 of 1V Zener voltage is connected in parallel with the sensor 2. If this oxygen sensor 2 is provided in the exhaust gas of an internal combustion engine of fuel rich, the resistance of the sensor 2 is several tens OMEGA and voltage of <=0.1V is generated in the sensor 2. Next, if it is provided in the exhaust gas of fuel lean, the resistance of the sensor 2 rises to >=100KOMEGA, but the voltage of the sensor 2 is kept at 1V by the Zener diode 4, whereby the deterioration occuring in the application of high voltage is prevented. |
