SCAVENGING DEVICE FOR 22CYCLE INTERNAL COMBUSTION ENGINE

摘要

PURPOSE:To prevent blowing over of gas at the initial stage of opening of a scavenging port by providing a check valve, which allows air flow toward inside of a cylinder from a scavenging chamber only, at an inlet end of an upper scavenging port of a device with upper and lower scavenging ports in a cylinder liner. CONSTITUTION:When a piston 5 descends and an upper scavenging port 21 opens, a lead valve 23 tightly adheres to a valve seat 24 to close an air passage 24a in case that pressure in a cylinder 111 is higher than that of a scavenging chamber 6, so that backward flow (blowing over) of gas in the cylinder to the scavenging chamber 6 can be prevented. When the piston 5 further descends and pressure in the cylinder 111 becomes lower than that in the scavenging chamber 6, the lead valve 23 is opened by the differential pressure and is pressed against a stopper 25, fresh air in the scavenging chamber 6 flows into the cylinder 111 through an upper scavenging port 21. When the piston 5 further descends, a lower scavenging port 22 also opens to let fresh air flow into the cylinder 111.