[aerohead]

My opinion is that you would want to limit,not increase the amount of strokes in an engine.The power-stroke is the only useful stroke,all the others are cannibalizing power from it, stored in the flywheel,or robbed from other firing cylinders,in the case of a multi-cylinder engines.Unless additional strokes add at least as much energy as the original power stroke,you're operating at higher internal friction loads for less net efficiency of the engine, since internal friction is already at a minimum.