| 摘要 |
The object of the present invention is to provide a controller for a heater for an air-fuel ratio sensor, and a method thereof, which activates the sensor element at an early stage so as to start the air-fuel ratio feedback control to clean the exhaust gas from the engine as early as possible, and avoids deterioration of the heater and the sensor element due to overheating thereof. The controller has a power supplying device for supplying electric power to a heater for heating an air-fuel ratio sensor arranged in an exhaust system of an internal combustion engine to maintain the air-fuel ratio sensor activated and has a resistance measuring device for measuring the resistance of the heater. The controller also has a power supply controlling device for controlling the power supply to the heater supplied by the power supplying device such that the resistance of the heater measured by the resistance measuring device is kept under a first upper limit when activating the air-fuel ratio sensor, and is kept under a second upper limit that is lower than the first upper limit after the air-fuel ratio sensor has been activated, thereby avoiding deterioration of the heater and the air-fuel ratio sensor.
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