A normal engine comprises two counter rotating multilobate cams, which are acted upon by a pair of diametrically opposed pistons, which are rigidly interlinked by connecting rods.

Our Engine design consists of two counter-rotating “trilobate” (three lobed) cams geared together, which transmits power directly & avoids the use (& losses) of a crank & a connecting rod. Two bearings run along the profile of both cams (four bearings in all) and stay in contact with the cams at all times. The bearings are mounted on the underside of the two inter-connected pistons, which maintain the desired clearance throughout the stroke. Differential gearing is provided to time the counter rotation of the cams. A shaft having a multilobate cam is axially fixed and an adjacent second multilobate cam is differentially geared to the first multilobate cam for axial counter rotation about the shaft. At least one pair of cylinders is used, with multilobate cams interposed there between with a piston in each cylinder and pistons of a pair of cylinders are rigidly interconnected.