Some engines use fewer strokes per cycle. A two-stroke engine accomplishes everything in two movements of the piston. But it's sloppier, because it burns oil and leaves some fuel unburnt.

Well, that claim is utter hokum here. The combustion cycle is textbook two-stroke. Can we believe the other claims Granada, Spain-based INNengine is making for its e-Rex "Patented 1 Stroke" engine?

Variable cycle engine design embodies a transformative approach in aero‐propulsion, enabling engines to adapt their thermodynamic cycle to meet diverse operational demands, from fuel efficiency ...

Compared to the four-stroke engine that produces one power stroke per two revolutions at 3,000 rpm, the four-stroke has 1,500 power strokes while the six-stroke would have 2,000.

Trick-Cycle Turbine Ltd. (TCT) is a South Dakota-based company led by inventor Reggie Huff that has created an engine design known as the Tomahawk TX Trick-Cycle Turbine engine.