two-stroke petrol engine with reduced pollution exhaust - has fan to supply scavenging air free to fuel

摘要

A two stroke petrol engine reduces the pollution in its exhaust gases by employing a system of scavenging which uses air which has not been mixed with fuel. The scavenging air is supplied by a fan on the crankshaft and flows into a rotating sleeve valve(10). This sleeve valve (10) shuts off the incoming air-fuel mixture whilst the scavenging air flows into the cylinder (6) through the port (5). As the sleeve valve continues to rotate it shuts off the scavenge air and allows the air-fuel mixture to flow into the cylinder (6).