Piston motion modifiable internal combustion engine

An internal combustion engine comprising:

• at least three radial cylinders disposed with their axes coplaner and equi-angularly disposed about a point common to each axis, the cylinders meeting to form a common combustion chamber;
• a piston located in each of said radial cylinders, each piston cooperating with a cam profile formed by the inner wall of a rotor, the cam profile being rotationally symmetrical and including the same number of lobes as pistons, each lobe projecting radially inwards, the lobes equi-angularly disposed about the inner wall, and
• wherein the engine is provided with a number of interchangeable rotors having differently shaped lobes.

An internal combustion engine comprising:

• at least three radial cylinders disposed with their axes coplaner and equi-angularly disposed about a point common to each axis, the cylinders meeting to form a common combustion chamber;
• a piston located in each of said radial cylinders, each piston cooperating with a cam profile formed by the inner wall of a rotor, the cam profile being rotationally symmetrical and including the same number of lobes as pistons, each lobe projecting radially inwards, the lobes equi-angularly disposed about the inner wall, and
• wherein each lobe is shaped with an innermost extent defining a camming surface of constant radial distance from the first axis thereby operatively causing each piston to maintain substantially a top dead centre position for a non-zero period of time.