| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent a gas sensor from damaging, degrading and lowering in detection accuracy, while preventing the device configuration from becoming complex and large-sized and avoiding excess energy consumption. <P>SOLUTION: A controller 10 is provided that sequentially carries out a first control mode and a second control mode. In the first mode which is carried out for a period, from the start clock time of supplying a power to the gas sensor 15 to a clock time, when a temperature in a gas detecting chamber 26 detected by a state sensor 37 (sensor peripheral temperature Ts) reaches a target temperature which is set previously; and operation of a heater 36 is controlled, based on the sensor peripheral temperature Ts. In the second mode which is carried out after the reaching of the sensor peripheral temperature Ts to the target temperature, the operation of the heater 36 is controlled, based on the sensor peripheral temperature Ts and a temperature of a gas to be detected (upstream gas temperature Tg) which is detected by a temperature sensor 41 on the upstream side of the gas sensor 15, such that the sensor peripheral temperature Ts is higher than the upstream gas temperature Tg, by a prescribed temperature or more (e.g., the prescribed temperature is set between 0°C and 5°C). <P>COPYRIGHT: (C)2009,JPO&INPIT |
