| 摘要 |
PURPOSE:To prevent the air-fuel ratio of an engine from varying due to a change in temperature, by calculating and updating a correcting value if the temperature of cooling water exceeds a predetermined value when a reference value for air-fuel ratio control is calculated in accordance with an output value from an oxygen concentration proportion type oxygen sensor and a correcting value to determine an output value for desired air-fuel ratio control. CONSTITUTION:An electronic control device 4 determines a reference value for air-fuel ratio control in accordance with values detected by an absolute intake-air pressure sensor 32 and a crank angle sensor 35 after completion of engine warm-up, and performs feedback control in accordance with a deviation between a value detected by an oxygen concentration proportion type oxygen sensor 1 and a desired value in order to obtain an air-fuel ratio in accordance with the operating condition of the engine. Further, electronic control device 4 determines a correcting coefficient in accordance with output signals from the absolute intake- air pressure sensor 32 and a crank angle sensor 35, and therefore, the reference value is corrected. A new correcting value is calculated again if a deviation between a detected air-fuel ratio and the desired value is below a predetermined value when the temperature of cooling water becomes higher than such a temperature corresponding to the temperature of intake air that fuel sticks on the inner surface of an intake-air pipe, and therefor it is updated.
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