| 摘要 |
PURPOSE: To compensate the deterioration of oxygen sensor outputs by detecting the bias of the oxygen sensor resulting from deterioration, and controlling the amount of fuel delivered to an engine according to the detected bias of the oxygen sensor. CONSTITUTION: A detection signal of a heated exhaust gas oxygen sensor 30 for detecting the oxygen content of the exhaust gas of an engine 11 is input to a fuel controller 100, and a total switching time(t) which is the total of a first switching time t1 for switching from a lean air-fuel composition to a rich air-fuel composition and a second switching time t2 for switching from the rich air-fuel composition to the lean air-fuel composition is measured with an oxygen sensor monitor 125 and checked to see whether or not the total switching time(t) is within a predetermined range. If the total switching time(t) is within the predetermined range, the difference between the first and second switching times t1, t2 is checked to see whether or not it is within a second predetermined range. If the difference is within the second predetermined range, the oxygen sensor 30 is determined to be operating effectively. If the difference is outside of the second predetermined range, a compensation value is calculated as a function of the difference in switching times to vary air-fuel ratio. |
