| 摘要 |
PURPOSE:To reduce the amount of the exhaust gas by closing an EGR control valve in the excessive operation where the load is changed from low to high, discharging the residual EGR gas in an EGR piping and a suction pipe from an exhaust bypass pipe, and guiding the air from a suction bypass pipe to a suction manifold. CONSTITUTION:The air from an air cleaner 18 is compressed by a compressor 4b in the EGR normal operation, and guided to an engine 1 through an intercooler 6 and a suction manifold 2. On the other hand, the exhaust gas is discharged through an exhaust pipe 5 and an exhaust turbine 4a, and a part of the exhaust gas is circulated to a suction pipe 8 through an EGR piping 13. In the excessive operation where the engine condition is rapidly changed from the low load to the high load, an EGR control valve 14 is closed, a three- way switching valve 12 is opened to the exhaust bypass pipe 11 side, and suction control valves 16, 17 are opened. The EGR gas to be left in the EGR piping 13 and the suction pipes 8, 9 is discharged through the exhaust bypass pipe 11, and the sucked air is guided from the suction bypass pipe 15 and sucked into the engine 1. |
