| 摘要 |
PURPOSE:To prevent blow-bye and increase the amount of charged air-fuel mixture by advancing the time at which a scavenging port for supercharging the air alone is opened and delaying the time at which a port with an intake valve for supercharging air-fuel mixture is opened and closed. CONSTITUTION:Air-fuel mixture in a cylinder 1 is ignited near the top dead center of a piston 2 and an exhaust valve 11 is opened to begin an exhaust when the piston 2 descends to a position 80 deg. degrees before a bottom dead center. When the piston 2 further descends to a position 50 degrees before the bottom dead center, a scavenging port 4 is opened, the compressed air supercharged by an air pump 13 being supplied from the scavenging port 4 and scavenging being conducted only by the air. An intake valve 10 is opened at a position 10 degrees before the bottom dead center, supplying compressed air-fuel mixture from an injector 7. In a position 10 degrees after the bottom dead center, exhaust valve 11 is closed. When the piston 2 is raised to a position 50 degrees after the bottom dead center, though the scavenging port 4 is closed, the intake valve 10 is kept opened until a position 80 degrees after the bottom dead center is reached, whereby the ample compressed air-fuel mixture can be supplied. |
