| 摘要 |
This invention concerns a turbo-charged engine with EGR comprising an EGR passage (11a, 11b) connecting an exhaust passage (4) upstream of a turbine (LT, HT) of a turbocharger (5) and an intake passage (3) downstream of a compressor (HC, LC) to each other for returning some of exhaust gas in the exhaust passage (4) to the intake passage (3), and an EGR valve (15a, 15b) provided in the EGR passage (11a, 11b) for adjusting a passage area of the EGR passage (11a, 11b). Capacity of the turbine (LT, HT) is set such that in a high speed and high load region of the engine operating state, if the exhaust gas is supplied to the turbine (LT, HT) with the EGR valve (15a, 15b) closed, the turbocharger overruns beyond a maximum speed limit, and if the EGR valve (15a, 15b) is opened to return some of the exhaust gas to the intake passage (3), the turbocharger rotates at less speed than the maximum speed limit. EGR can be performed in the high speed and high load region of the engine operating state without reducing power output and worsening fuel consumption. <IMAGE> |
