| 摘要 |
PURPOSE:To control the pressure of a pressure chamber well by a method wherein second pressure, higher than first pressure, is introduced into the pressure chamber, first pressure path is arranged with a valve body energized toward the closing direction thereof and the second pressure path is arranged with a slidable moving core. CONSTITUTION:When the pressure in the pressure chamber 7 is a predetermined value, the first pressure introducing path 8 is closed by the valve body 17 and the second pressure path 19 is also closed by the flange 21 of the moving core 20 and the valve body 17. Vacuum of a given value in the pressure chamber 7 is outputted to an EGR control valve through a port 5. In case a voltage, impressed to a coil 9, is to be weakened to increase the pressure of the chamber 7, the moving core 20 is moved toward the chamber 7 due to the pressure difference between both surfaces and atmospheric pressure is introduced into the chamber 7 through the path 19. On the contary, in case the pressure in the chamber 7 is to be reduced, current, being impressed to the coil 9, is increased to open the path 8 and vacuum is introduced into the chamber 7 to reduce the pressure. |
