| 摘要 |
PURPOSE:To maintain the pressure in a pressure chamber at a prescribed value and thereby to control the quanity of recirculated exhaust gas precisely, by opening a first value introducing an intake pipe negative pressure into the pressure chamber of an exhaust gas recirculation control valve, and a second valve introducing the atmospheric pressure, at almost the same timing. CONSTITUTION:A valve seat 13 and the valve body 12 of an exhaust control valve 10 are provided in the middle of the line of exhaust gas recirculation conduits 6 and 7 connecting the exhaust pipe 5 and intake pipe 4 of an engine 1. Connected to the pressure chamber 14 of the exhaust control valve 10 is a conduit 32, into which an intake pipe negative pressure is introduced via a first solenoid valve 21 and the atmospheric pressure via a second solenoid valve 22. The timing of the opening of each of the two solenoid valves 21 and 22 is controlled through operation by a control circuit 28 to which a detection signal from an intake pipe negative pressure sensor 24 and an electromagnetic pickup 27, and opening signals are given to these valves at almost the same timing. |
