| 摘要 |
PROBLEM TO BE SOLVED: To heat an EGR pipe during warming-up operation in which an EGR valve is closed with a simple structure.SOLUTION: An upper cone 7b of a catalyst case 6 is fixed to an exhaust manifold 5, and an EGR pipe 10 is connected to a lower cone 7c of the catalyst case 6 and a cylinder head 2. One end 16a of a bypass pipe passage 16 is connected to the other end 10b of the EGR pipe 10, and the other end 16b of the bypass pipe passage 16 is connected to the downstream side of the lower cone 7c of an exhaust pipe 9. During warming-up operation in which an EGR valve 13 is closed, a part of exhaust gas is returned to the exhaust pipe 9 from the EGR pipe 10 through the bypass pipe passage 16. When the EGR valve 13 is opened, the EGR gas is recirculated into an intake system from both of the EGR pipe 10 and the bypass pipe passage 16. |
