Abstract: The invention provides the mechanism for an internal combustion engine that utilizes a radial flow of combustible gases about the axis of a toroid or annulus cylinder. The principal components consist of a rhomboid linkage mechanism operating within a stationary cam. The mechanism sustains torque from two coaxial drive shafts upon which the mechanism imposes a compound rotary motion whereby an angular harmonic is superimposed over a constant angular velocity. This motion is applied through discs to two pair of pistons within the cylinder to effect a radial flow with a precisely defined theoretical cycle. Where the mechanics are used for a radial flow engine, the power generated is taken from the rhomboid mechanisms by a coupling and final drive shaft.Further the invention includes within its scope a method by which the discs are self sealing and the means of producing a multicylinder unit.