A rotary piston external combustion engine, comprising:
- means for compressing air and expanding combusted gas;
- a shaft connected to the compressing and expanding means for delivering power by means of an external drive shaft;
- an air inlet port opening for admitting ambient air in the air compressing means;
- an outlet valve for venting the compressed air out when the pressure thereof exceeds the air pressure downstream of the valve;
- an exhaust port opening in an external structure for venting the combusted gas out of the gas expanding means;
- means for receiving compressed air from the air compressing means, means for mixing a fuel with the compressed air, means for igniting the mixture to produce combusted gas, and means for delivering the combusted gas to the expanding means,
- the compressing and expanding means including a plurality of rotor bodies, a plurality of generally oval-shaped hollow external structures surrounding and enclosing the rotor bodies, flange means for rotatably supporting the rotor bodies by the hollow external structures about the shaft axis, each one set of rotor body and associated hollow structure being positioned between two adjacent flanges, each external hollow structure having a continuously curved surface and each rotor body having three identical side curved surfaces positioned to face cooperating portions of the curved surface of the hollow external structure, any two adjacent side curved surfaces forming an intersection line parallel to the rotor rotational axis of symmetry and all such parallel lines thus formed being equidistant from one another and continuously substantially coinciding with a generatrix of the corresponding continuous curved surface of its associated external structure, each rotor side curved surface defining a variable volume sealed space in cooperation with the flange means and the external structure curved surface, seals positioned at locations where the side curved surfaces and the external structure curved surface come into sliding contact, the shaft having a plurality of off-centered cylindrical journal bearing lands and each rotor having a corresponding centered cylindrical journal bore for rotation around a cooperating journal bearing land, each rotor having one centered internal gear and one of the two flanges associated with said rotor having a pinion gear for engaging said internal gear of larger pitch circle diameter, the curvatures and relative positions of the facing surfaces being such that four of the sealed spaces are formed and progressively vary in volume as the rotor rotates, one set of two of said four spaces decreasing in volume while the other set of two spaces increase in volume, as relative displacement of the facing surfaces takes place, wherein the generally oval-shaped curved surface of each hollow structure has two orthogonal planes of symmetry defining two generatrices of the external structure curved surface that are the farthest opposed and two generatrices of the external structure curved surface that are the most closely opposed where two seals are located, one for each generatrix, for sealing sliding contact with the rotor curved sides that form three apices at their junction and three lobes therebetween, each apex being provided with a seal in continuous sliding contact with the external structure curved surface, and wherein four port openings are provided, one on each of the to sides of each one of the two most closely opposed generatrices, one first port being used as air inlet, the diametrically opposed second port being used as combusted gas inlet, a third port located substantially symmetrically to the first port with respect to the longest axis of the oval shape being used as compressed air outlet, and a fourth port located substantially diametrically opposed to the third port being used as expanded combusted gas exhaust port, whereby air admission occurs after a rotor apex has passed the first port while the inlet-vented sealed space volume increases, air compression occurs after the inlet is closed off by the rotor next apex and said volume then decreases, combusted gas admission occurs after one rotor apex has passed the second port, combusted gas admission occurs thereafter until a combusted gas inlet valve in control of the second port closes and then enables the combusted gas to expand until the rotor apex opens the fourth port or exhaust port;
- means for detecting the position of a rotor lobe and associsted apex after said apex has passed the second port;
- means for utilizing said rotor lobe position to monitor the actuation of the combusted gas inlet valve;
- and
- means for actuating said combusted gas inlet valve;
- whereby the gearing ratio between the pinion gear and the internal gear is two thirds, each rotor has three curved sides and three apices, and the oval-shaped internal surfaces of the hollow external structures is shaped like two intersecting and symmetrical quasi-circular arcs, each one arc covering over half of a full circle, said intersections defining the locations of the most closely opposed generatrices.