While the most rotary engines use the principle of volume variations between a curve and moving cord of fixed length, this new engine concept uses a four-degree of freedom rotor inside an internal housing contour, and does not require a central shaft or support.
The invention is an assembly of four carriages supporting the pivots of four blades forming a variable shape rotor. This rotor rolls just like a roller bearing on the surface of an internal contour wall. During the rotation the rotor pivoting blades align alternatively in a lozenge and square configuration. All ports are radial in the housing and /or axial on the lateral side covers. Since he compression and expansion strokes start and end simultaneously, an ignition flame transfer slots is used to maintain a continuous combustion while four strokes are completed in every revolution. A central shaft is not required for the engine to operate, but can be added and driven by blades, through a mechanical arms coupling.