Two-stroke IC engine - has charge transfer from crankcase controlled by rotary valve driven from crankshaft

摘要

The two-stroke internal-combustion engine has a closed crankcase containing a crankshaft driven by a piston. The latter controls the exhaust port in the cylinder while the crankcase has an inlet for the fresh fuel/air mixture, controlled by a rotary valve driven from the crankshaft. A transfer passage runs from the crankcase to the cylinder. Transfer of the mixture from the crankcase (10) to the cylinder (14) is controlled by a second rotary valve (20), also driven from the crankshaft (11), in the transfer passage (19). This allows supply to the cylinder at a point off the axis through the top dead centre and bottom dead centre positions, and also opening of the transfer port to be delayed in relation to that of the exhaust port, without adversely affecting the timing of the shutting of these ports.