| 摘要 |
PURPOSE:To prevent the occurrence of the change in the characteristic of a heat-ray type suction quantity sensor with the elapse of time caused by the substance adhering to the surface of the sensor, by cumulating the operation time of an internal combustion engine and carrying out burn-off at the point of time when the cumulative value reaches a predetermined value. CONSTITUTION:An electric control unit 10 measures the output of a suction quantity sensor and the number of rotations or total operation time of an internal combustion engine and stores the cumulative value thereof in an RAM 105b. A CPU 105 compares the cumulative value of the RAM 105b with a predetermined value during the stoppage of the engine and carries out burn-off when the cumulative value exceeds the predetermined value. That is, a burn-off pulse 108 is applied to the heat ray type suction quantity sensor 2 from a drive circuit 107 and the substance adhered to the surface of the sensor is burnt off at high temp. As mentioned above, by periodically burning off the sensor 2, the characteristic change of the sensor 2 can be reduced.
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