Four-cycle internal-combustion engines in which a four-stroke cycle is carried out during a single revolution of the main shaft of the engine. For the purposes of this definition of continuous movement of the working piston in one direction is considered as two strokes and the sequence of the strokes is varied from that present in engines working on the ordinary four-stroke cycle, the working stroke being followed by the charging stroke as the piston moves in one direction and the exhaust and compression strokes taking place in the order named as the piston moves in the reverse direction.
(1) Note. For engines working on this cycle, but having two or more working cylinders, see this class, subclass 53.
(2) Note. For other engines in which the four strokes comprising a single cycle occur during a single revolution of the main shaft of the engine, see this class, subclass 78.
