| 摘要 |
PROBLEM TO BE SOLVED: To suppress increase in size and in cost of a fresh air introduction valve by reducing a load applied to the fresh air introduction valve at supercharging.SOLUTION: An EGR (Exhaust Gas Recirculation) device of a low-pressure loop type provided in an engine 1 with a supercharger 7 includes an EGR passage 17 which makes a part of an exhaust gas discharged to an exhaust passage 5 from a combustion chamber 16 flow to an intake air passage 3 as an EGR gas, and makes it recirculate, and an EGR valve 18 which adjusts a flow of the EGR gas in the EGR passage 17. An inlet 17b of the EGR passage 17 is connected to the exhaust passage 5 positioned downstream of a turbine 9, and an outlet 17a is connected to the intake air passage 3 positioned upstream of a compressor 8. A fresh air introduction device includes a fresh air introduction passage 41 which introduces fresh air into the intake air passage 3 positioned downstream of a throttle valve 21 from an atmosphere side, and a fresh air introduction valve 42 which adjust a fresh air amount flowing in the fresh air introduction passage 41. A check valve 43 which prevents a counter flow of intake air is provided in the fresh air introduction passage 41 positioned upstream or downstream of the fresh air introduction valve 42. |
