| 摘要 |
PURPOSE:To enable a sufficient amount of exhaust gas to be recirculated, when the passage area of an exhaust gas passage is widened to decrease the pressure on the exhaust side in spite of being in the opened valve region of an EGR valve, by controlling the EGR valve by an EGR valve control means so as to have a wider opening. CONSTITUTION:The interior of the exhaust gas passage 8 connected to the inlet port of the turbine 9 of a turbocharger 3 is divided into two parts, and on the inlet side on one side an open/close valve 10 as a passage varying means is provided. The open/ close valve 10 is controlled so as to be closed when the operating condition of an engine is in a low-speed and low-load region. In the engine like this, an EGR passage 13 is connected to the exhaust gas passage 8 on the upstream side of the turbine 9 and to the intake air passage 5 on the downstream side of a blower 4, and in this passage an EGR valve 14 is interposed. And the EGR valve 14 is controlled by a control unit 25 so as to be opened in a prescribed operating region, and further, when the EGR valve 14 is opened and also the open/close valve 10 is opened, the opening of the EGR valve 14 is controlled so as to be opened wider than that when the open/ close valve 10 is closed. |
