Two=stroke IC engine with stepped piston - has transfer port between crankcase and cylinder in piston instead of in cylinder

摘要

The engine has a cylinder with inlet and exhaust ports and a piston reciprocating in it. The piston has a wider lower section and a narrow upper section. The narrow section slides in a narrow extension at the top of the cylinder. The working surface is formed by the conical transition between the wider and narrower sections of the piston and combustion takes place below the upper projection of the cylinder. The transfer port between the crankcase and the cylinder is formed in the upper narrow section of the piston. The port is closed when the narrow section enters the upper portion of the cylinder and opens again on the next downstroke. The design reduces limitations on possible port sizes.