| 摘要 |
PURPOSE:To enable high-precise calibration of a change in characteristics, by a method wherein a detecting signal provided under a given known air-fuel ratio state, except a theoretical air-fuel ratio, from an air-fuel sensor for continuously detecting an air-fuel ratio is inputted, and a sensor is calibrated according to a change from an initial value. CONSTITUTION:An electronic control unit 8 inputs signals from a number of revolutions sensor 9, a throttle sensor 10, an intake air amount sensor 11, etc. together with a signal from an air-fuel sensor 7 capable of continuously detecting in a range of from a rich air-fuel ratio to a lean air-fuel ratio, and controls the opening time of a fuel injection valve 3 through feedback so that an air-fuel ratio is adjusted to a desired value according to a running state. The electronic unit 8 detects the output state of the air-fuel sensor 7 when atmosphere in an exhaust manifold 6 responds to a predetermined known air-fuel ratio, i.e., when the atmosphere is in an atmospheric state, and based on a deviation between the current value and an initial value, output characteristics of an air-fuel ratio is calibrated.
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