| 摘要 |
PROBLEM TO BE SOLVED: To prevent the an air-fuel ratio sensor from being damaged by wetting and the combustion of soot and the like when being heated by a heater. SOLUTION: This air-fuel ratio sensor comprises the air-fuel ratio sensor 37, the heater 76 for heating the air-fuel ratio sensor 37, an energizing means 60 for energizing the heater 76 to keep an arbitrary temperature, and a determining means 35 for determining whether the water is attached to an inner wall of an exhaust passage 19 or not, and the heater 76 is energized to keep the air-fuel sensor 37 at a temperature lower than an ordinary temperature when the attachment of the water to a wall face of the exhaust passage 19 is determined. |
