| 摘要 |
PURPOSE:To always carry out the optimum EGR control by carrying out the selection from the downstream side EGR means to the upstream side EGR means of a supercharger installed in the intake passage of an engine, keeping a prescribed overlap period, on condition that the downstream side intake passage pressure is lower than the atmospheric pressure. CONSTITUTION:A supercharger is installed midway in an intake passage of an engine, and the first and second exhaust gas recirculation means for introducing EGR gas are arranged above and below the supercharger. Further, one between the first and second intake gas recirculation means is selectively switched according to the operation state of the engine, and EGR control is carried out. In this case, the selection from the second exhaust gas recirculation means to the first exhaust gas recirculation means is executed by a selection control means, keeping a prescribed overlap period, and on condition that the intake passage pressure on the downstream side of the supercharger is low. Accordingly, the EGR control which is optimum in all the operation regions of the engine is executed, and the exhaust emission is improved, and the traveling performance can be improved. |
