Beare head engine

The Beare-head engine internal combustion engine technology combines a four-stroke engine bottom end with a ported cylinder head closely resembling that of a two-stroke engine. The head piston is smaller and moves at half the speed of the opposing piston. Functionally, the cylinder-head piston replaces the valve mechanism of a conventional four-stroke engine. This configuration has been described as a six-stroke engine based on adding together the four strokes per cycle of the bottom end and the two strokes of the cylinder head.