| 摘要 |
PURPOSE:To eliminate the dead time of an engine and as well to make it possible to minimize the range of variations in air-fuel ratio, when the air-fuel ratio varies at the boundary of a reference voltage, by controlling the air-fuel ratio with the use of the coefficient of air-fuel ratio which is obtained at the time point retroacted by a predetermined number of cycles from the time of variation. CONSTITUTION:An oxygen sensor 2 detects the concentration of exygen in exhaust gas from an engine 1 and delivers its output to an MPU3. There is a predetermined delay (dead time) until fuel which is taken into at a predetermined air-fuel ratio is burnt and reaches an exhaust pipe, and this predetermined delay is proportional to the cycle period of the engine. Therefore, the output of the oxygen sensor 2 is utilized, which is obtained at a sampling time point that is retroacted by a predetermined number of cycles from the time point at which the output of the sensor 2 crosses a reference voltage. Further, as to the step gain, when the output of the sensor 2 is inverted from the rich to the lean or the lean to the rich, the optimum control is made by means of a throttle actuator 4 with the use of a compensating value for the air-fuel ratio which is obtained before the dead time previously set. |
