| 摘要 |
PURPOSE: To prevent spouting of black smokes by closing an EGR valve for stopping the recirculation or the exhaust gas, opening a suction side solenoid valve furnished in the suction side pressure line, supplying thereby the pressurized air from a pressure source to a supply pipe, and diluting the exhaust gas remaining in an EGR pipe. CONSTITUTION: When an engine 1 is in low load operation, a solenoid valve 2 is opened by a controller 14 of an EGR control device 20, and thereby an EGR valve 9 is opened with the pressurized air from a pressure source 11. Part of the exhaust gas G in an exhaust pipe 6 is introduced to a suction pipe 3 through an EGR pipe 8 so that feedback is made with the exhaust gas. When the revolving speed and load of the engine 1 have increased, the EGR valve 9 is closed. At the same time, a suction side solenoid valve 19 is opened by a controller 14 through the action of a timer 21, and thereby the pressurized air is supplied to the suction pipe 3 via the suction side pressure line 18. Thereby shortage of the air immediately after the EGR valve 9 is closed, is eliminated, and the exhaust gas remaining in the EGR pipe 8 is diluted. |
