| 摘要 |
PURPOSE:To keep the rate of exhaust-gas recirculation (EGR) always at a proper value, by providing a valve for converting the partial vacuum or the negative pressure at a venturi at a portion of a line for feeding the negative pressure of the venturi in a system in which an EGR valve is actuated by the negative pressure in a vacuum pump controlled by a vacuum amplifier. CONSTITUTION:A line 15 for detecting the negative pressure in an air cleaner 1 is connected to a fuel injection pump 14, and its branch pipe 15a is connected to a vacuum amplifier 12 which is adapted for controlling the negative pressure of a vacuum pump 13. On the other hand, a line 16 for detecting the negative pressure at a venturi 2 is similarly connected to the pump 14, and its branch pipe 16a is connected via an orifice 17 to a valve 20 for converting the negative pressure at the venturi. The branch pipe 16a is also connected to a line 16b communicated to the vacuum amplifier 12. Here, the valve 20 comprises a chamber A to which the negative pressure at the venturi is transmitted, a chamber B to which the negative pressure at a portion between the venturi 2 and the air cleaner 1 is transmitted, a chamber C communicated to the atmosphere, and a chamber D communicated to an output line 26. |
