| 摘要 |
PROBLEM TO BE SOLVED: To provide a heater control device for an air-fuel ratio sensor which can prevent excessive heating of a heater after the activation of the air-fuel ratio sensor. SOLUTION: Immediately after the start of an internal combustion engine, current is passed continuously until the temperature of a heater 112 reaches about 1100 deg.C. Basic power is determined so that the heater temperature is thereafter kept at 1100 deg.C, and so that a detecting element 11 is kept at 710 deg.C after the activation of an air-fuel ratio sensor, and corrected power calculated as a function of cooling water temperature is increased. When the increased corrected power exceeds 1100 deg.C basic power after the activation of the air-fuel ratio sensor, the power is limited to the 1100 deg.C basic power to prevent excessive heating and damaging of the heater. |
