Abstract: Rotary valves for internal combustion engines according to embodiments of the present invention comprise a conical valve portion with a first port of the rotary valve for feeding a fuel to the combustion chamber, respectively for an outlet of an exhaust from the combustion chamber, whereas the first port is located within a superficies surface of the conical valve portion; furthermore a cylindrical valve portion is arrange at a thick end of the conical valve portion, whereas a second port of the rotary valve for the fuel, respectively for the exhaust is located within a superficies surface of the cylindrical valve portion.