| 摘要 |
PROBLEM TO BE SOLVED: To enable the recirculation of EGR gas having the sufficient flow rate by increasing the pressure differential before and after an EGR valve in the low load of an engine. SOLUTION: In a turbocharger 11, an exhaust turbine 13 and an intake compressor 12 are coaxially connected to each other. In this case, a primary EGR passage 31 for making the upstream side of the exhaust turbine 13 communicate with the downstream side of a throttle valve 7 and a secondary EGR passage 32 for making the downstream side of the exhaust turbine 13 communicate with the upstream side of the intake compressor 12 are provided, and these two EGR passages 31, 32 are selectively used according to the operating conditions of an engine. The secondary EGR passage 32 is shut off in a low loading of the engine, and the primary EGR passage 31 is used. |
