Abstract: This is a continuation-in-part to a previous patent application now pending entitled Two-Rotor Engine, Ser. No. 542,250. In accord with said patent pending, the present invention also involves an engine comprising a cavity of genus 1 generated by the revolution of a rectangle about an axis. Two sets of diaphragms with n diaphragms in each set are alternated inside the cavity of revolution, separating the cavity in 2n chambers, the volume of n chambers increasing while the volume of the other n chambers is decreasing when the two sets of diaphragms are forced to rotate with respect to each other. In the present invention, one set of diaphragms is attached to a center rotor, the other set being attached to a side rotor. While in the Two-Rotor Engine, the two sets of diaphragms are attached to the two side rotors which, in turn, are connected to the two side gears of a differential assembly. The changing of volume of chambers is used to execute complex thermodynamic cycles.

Abstract: A multi-stroke engine for converting energy into torque is described including two rotors and a housing along surfaces of revolution of genus 1 about same axis. In the preferred configuration a cavity of revolution is used, generated by the revolution of a rectangle about the axis, two sides of the rectangle being parallel to the axis; one half of the cylindrical surface generated by the side nearest the axis is allocated to each rotor, while the surface generated by the other three sides of the rectangle is allocated to the housing. n substantially similar diaphragms having azimouthal thickness substantially equal to 90/n.degree. extend from each rotor at azimouthal angles 360/n across the cavity of revolution and are interleaved with the diaphragms of the other rotor so that the diaphragms divide the cavity of revolution in 2n chambers the volume of half of the chambers increasing while the volume of the others is equally decreasing as the rotors are pressured to rotate with respect to each other.