| 摘要 |
PURPOSE:To decrease consts and to improve accuracy by providing a logic circuit which performs logical operation of the outputs of a plurality of load detecting switches whose actuating pressures are changed, thereby detecting the load areas whose number is more than the number of the switches. CONSTITUTION:At the downstream of an air intake path 3, an exhaust gas returning path 9, which returns the exhaust gas to the air intake path 3, and a throttle valve 4 are provided. At the upstream side of the valve 4, negative pressure taking out paths 5a, 5b, and 5c are sequentially provided in correspondence with the opening and closing operations of the valve 4, and sequentially operated by the switches 7a, 7b, and 7c from the downstream side, in response to the change in the intake negative pressure. Meanwhile, with the further increase in the opening degree of the valve 4, the negative intake pressure is decreased, and the inoperative states are sequentially obtained by the switches 7a, 7b, and 7c from the downstream sides in response to said decrease. The operating state of said switches are detected and judged by the logic circuit 8, and seven load areas are detected from the three switches 7a, 7b, and 7c. Thus the returning of the exhaust gas is finely controlled. |
