| 摘要 |
<P>PROBLEM TO BE SOLVED: To ensure a desired amount of EGR gas while ensuring a desired amount of intake air in a high-load high-rotation operation region of an engine. <P>SOLUTION: A high-pressure stage turbo 2 and a low-pressure stage turbo 3 are connected in series to an engine 1, and the high-pressure stage turbo 2 is mounted with an electric motor 2M. When the high-load high-rotation operation state of the engine 1 is detected by operation state detecting means 8, 9, an EGR valve 20 provided in an EGR passage 18, and an intake bypass valve 24 provided in an intake bypass passage 23 bypassing a high-pressure stage compressor 2C, are opened, and the opening of an exhaust bypass valve 22 provided in an exhaust bypass passage 21 bypassing a high-pressure stage turbine 2T is throttled. Further, the electric motor 2M is driven to reversely rotate the high-pressure stage turbo 2. Pressure in an exhaust passage 5 upstream of the high-pressure stage turbine 2T is thereby made higher than pressure in an intake passage 4 downstream of the high-pressure stage compressor 2C. <P>COPYRIGHT: (C)2012,JPO&INPIT |
