Said invention can be used for transport means, sports cars and power plants. The inventive engine comprises a hollow toroidal working cylinder provided with a continuous circular slot embodied along the small
diameter thereof, a
nozzle or a
spark plug and arc-wise extended input and output orifices embodied in the wall thereof for admitting air or air-fuel mixture and exhausting
combustion gases. The novelty of the inventive engine lies in that the transmission gear thereof is provided with four eccentrics whose
crankshaft necks are fixed to the axial holes of the pinions and arranged in the four bores of a fly wheel, whose axes are circumferentially disposed at an even
pitch. The
crankshaft necks are connected to the bearing elements through connecting rods each of which is arranged by the ends thereof in such a way that they are rotatable about the
crankshaft neck and an axis disposed in the wall of one of the bearing elements. The particular embodiments of the invention relates to the relative positions of the fly wheel and bearing elements determining the different forms of the fly wheel embodiment and the connections thereof to the pinions. The invention makes it possible to exclude load impacts to the transmission gear, reduce other loads applied thereto and the friction
power loss and to ensure more flexible connections there between, thereby increasing the engine performance, the reliability and overhaul period thereof, reduce the size and
mass of the elements of the transmission gear and extend the possibility for specifying the behaviour of speed variation of the
relative motion of the bearing elements.