| 摘要 |
PURPOSE:To prevent the learning of air-fuel ratio from progressing in the faulty direction and secure safety of control by interrupting the fuction of a learning compensation coefficient updating means when the maximum and minimum values obtained by an O2 sensor signal state detecting means are not over and below the specified value, respectively. CONSTITUTION:The maximum value Vmax and the minimum value Vmin within one period of the output voltage of an O2 sensor 8 is detected, and n case of Vmax<=Vx, the O2 sensor is judged to be deteriorated and, furthermore, in case of Vmin>Vy, the deterioration thereof is also determined. In those cases, further learning cannot be expected any more so that the updating of a learning compensation coefficient alpha0 is interrupted. Based on the signals from a car speed sensor 19, a neutral switch 15 and a throttle sensor 6, any variation in car speed, the gear position and any variation in opening of a throttle valve are discriminated, respectively. The cases that the variation in car speed exceeds the specified value within the specified period, the gear is shifted into the neutral position and variation in opening of the throttle valve exceeds the specified value constitutes the judgement of a transient state, on account of which the coefficient alpha0 will not be updated. The safety of the leaning control may be, therefore, improved. |
