while the exhaust is escaping?
Not all that well! Two stroke engines fire on every revolution, so exhaust and transfer must take place at the same time. Transfer is the process of moving the compressed fuel/air mix in the crankcase to the above the piston. Since this takes place during the period the exhaust is open, it is the design of transfer ports, exhaust and piston that determines the “scavenging efficiency”; ie, how much exhaust and new charge is expelled through the open exhaust port(s) verses how much of the new charge and burnt gas is retained in the cylinder for secondary compression and combustion. This is common to all 2-strokes and is one of the reasons some governments are considering banning the type all together because of their contribution to hydrocarbon pollution. Typically, a 2-stroke exhaust opens a few degrees before transfer starts. This means that most of the pressure in the cylinder has been relieved by the time the transfer port(s) open. Because the fuel/air mix in the crankcase is compres
Not all that well! Two stroke engines fire on every revolution, so exhaust and transfer must take place at the same time. Transfer is the process of moving the compressed fuel/air mix in the crankcase to the above the piston. Since this takes place during the period the exhaust is open, it is the design of transfer ports, exhaust and piston that determines the “scavenging efficiency”; ie, how much exhaust and new charge is expelled through the open exhaust port(s) verses how much of the new charge and burnt gas is retained in the cylinder for secondary compression and combustion. This is common to all 2-strokes and is one of the reasons some governments are considering banning the type all together because of their contribution to hydrocarbon pollution. Typically, a 2-stroke exhaust opens a few degrees before transfer starts. This means that most of the pressure in the cylinder has been relieved by the time the transfer port(s) open. Because the fuel/air mix in the crankcase is compres
