| 摘要 |
PURPOSE:To facilitate compaction of a turbocharger and improve engine characteristics, by designing to selectively introduce either supercharged air only or supercharged air and naturally aspirated air into an operation chamber of an engine. CONSTITUTION:There are provided a primary suction port 7 and a secondary suction port 8 on a side housing 2 of an engine casing. The primary suction port 7 is connected to a primary suction passage 13 including a supercharging blower 47 and a primary throttle valve 28, while the secondary suction port 8 is connected to a secondary suction passage 14 including a secondary throttle valve 29. It is designed that either supercharged air only or supercharged air and naturally aspirated air may be selectively introduced into an operation chamber 5 according to an engine running condition, so as to make a turbocharger 11 compact. Further, it is designed that a maximum value of supercharged pressure controlled by a supercharged pressure control valve 17 may be set to be higher by a predetermined pressure during opening of the throttle valve 29 than during closing of the throttle valve 29. |
