Abstract: Improved designs for the internal combustion engine are disclosed. The first embodiment of the invention relates to a configuration in which the cylinder/piston assembly is inclined at an oblique angle relative to the center axis of rotation of the crankshaft and connected to the crankshaft with a curved or bow-shaped connecting rod. The second embodiment of the invention resides in an improved design for the combustion chamber. In this embodiment, the cylinder and piston have elliptical cross sections. This, combined with a concave cylinder head, provide for a ellipsoid shaped combustion chamber. In this chamber are mounted two spark plugs, positioned along the major axis of the ellipse defined by the cylinder cross section. This configuration then sets the stage for the phenomenon called "Dual opposite firing fronts.