Abstract: A rotary internal combustion engine of the type comprising a power rotor provided with a number of axially extending lands, an abutment rotor intermeshing with said power rotor and provided with a higher number of axially extending grooves than that of the lands of the power rotor, and a casing carrying and sealingly enclosing said intermeshing power rotor and abutment rotor and forming together with the flanks of said rotors moving chambers containing air with different pressures. A carburetor or similar type of fuel injecting means is provided in a channel forming a communication between a first chamber where the air has been partly compressed and a second chamber in which the air is at least substantially uncompressed.