| 摘要 |
PURPOSE:To provide the intake device of an engine provided with a mechanical supercharger, thereby the intake device can sufficiently enhance the scavenging performance while preventing the generation of blow-by in the all driving range, and has a simple structure. CONSTITUTION:In an engine VE provided with a mechanical supercharger, the opening overlap period is small in the low rotational range, while it is large in the high rotational range, in the low intake air amount range where a S-valve 30 (intake passage opening/closing valve) is closed. Moreover, in the high intake air amount range where the S-valve 30 is opened, the opening overlap period is small in the low rotational range, while it is large in the high rotational range. Accordingly, the opening overlap amount can be gradually increased by four steps according to the rise of engine speed by a simple structure wherein a VVT 9 (valve timing variable means) is provided to only intake valves 1a, 1b, and the scavenging performance can be enhanced to the approximately maximum while preventing the generation of blow-off in the all driving range. |
