| 摘要 |
PURPOSE:To feedback-control mixed air to a desired air-fuel ratio by using an oxygen sensor made by opposing an oxygen pump element and an oxygen concentration cell element, dividing and composing the detected signals in a rich area and lean area and obtain signals corresponding to the air-fuel ratio in the whole area of the rich area and lean area of mixture. CONSTITUTION:An oxygen concentration cell element 32 and an oxygen pump element 36 are installed in opposition to each other in an exhaust manihold 3 through a fitting member 31. A theoretical air-fuel ratio detecting element 40 detects the theoretical air fuel ratio and outputs the theoretical air fuel ratio that can discriminate the lean area and rich area of air-fuel ratio. It controls electromotive force of the cell element 32 or pump current that flows in the pump element 36. In the lean area and rich area of the air-fuel ratio, it inverts air fuel-ratio signals corresponding to respective air-fuel ratios based on the theoretical air fuel ratio signal when the air fuel ratio is in the lean area or rich area and enables to detect the real air-fuel ratio signals corresponding to the air- fuel ratio in all areas of air fuel ratio. Thus, feedback control of air-fuel ratio to a desired air-fuel ratio is made possible. |
