Air cooled two stroke engine - has linkage connecting throttle to hinged sprung flap lifted by air from fan

摘要

The air-cooled, two-stroke engine (1) has a carburettor (2) with a throttle (3) connected by a link (9) to a hinged flap (6). An adjustable tension spring (10) pulls the flap (6) down over the cooling fins (7). A centrifugal fan (4) with curved blades (5) mounted on the crank-shaft directs a stream of cooling air against the flap (6). The pressure of the air lifts the flap (6) against the force of the spring (9), and actuates the throttle (3) so that the engine speed is reduced. The flap (6) thus acts as a speed governor and at the same time controls the flow of air over the cooling fins (7), through the gap (8) to the region between cylinder block and exhaust (11).