Abstract: In one embodiment, the present invention is directed to a linear engine comprising: a piston; a linear piston leg comprising two opposite cogged edges including: lowering cogs and raising cogs; at least one lowering segmental cogwheel, the cogs of which correspond to said cogs of one edge of said linear piston leg; at least one raising segmental cogwheel, the cogs of which correspond to said cogs of one edge of said linear piston leg; and a transmission system connecting said cogwheels to a driveshaft; wherein each of said segmental cogwheels comprising at least two opposite cogged segments and two opposite cogless segments.