About Perfectly stratified scavenging

01

As the piston rises, the intake port opens and air-fuel mixture fills the inside of the crankcase.
Meanwhile, air is filled into the upper part of the scavenging passage through the reed valve in the air passage.
During this time, the air-fuel mixture is ignited and the pressure increases in the combustion chamber.

02

The pressure inside the combustion chamber causes the piston to move downward, opening the exhaust port and forcing out the combustion gases.

03

When the piston moves further down, the scavenging port opens and the air that was filled in the upper part of the scavenging passage is supplied to the inside of the combustion chamber. (At this time, some air may get caught up in the flow of combustion gas and blow directly into the exhaust port, but this is air that is not a mixture and does not lead to the emission of unburned gas components or worsening fuel consumption.) yeah.)

04

The air is then followed by the mixture. When the combustion gas remaining in the combustion chamber is exhausted, air forms a boundary layer between the air-fuel mixture and the combustion gas, and mixes with the combustion gas, greatly reducing the amount of fuel discharged.