Abstract: Apparatus and associated methods relate to a modular rotary engine with a rotating valve shaft assembly. The rotating valve shaft assembly controls the timing of operations that alternately load and seal compressed air in a plurality of adjacent combustion chambers and alternately unload the high-temperature, high-pressure combustion gases from the adjacent combustion chambers into one or more expansion modules. The rotating valve shaft assembly includes at least two rotating valve shafts. Each rotating valve shaft includes ports that alternately open to allow a flow of compressed air from the compression module into a combustion chamber; and close to allow the injection of fuel into the combustion chamber and ignition of the compressed air and fuel mixture. The rotation of the drive shaft of the rotary engine is powered by the expansion of expanding combustion gases that turns the expansion rotor.

Abstract: An engine system includes a plurality of adjacent expansion rotor housings each having a generally cylindrical expansion rotor cavity. The expansion rotor cavity of each expansion rotor housing is substantially aligned with the expansion rotor cavity of each other expansion rotor housing. An elongated shaft extends through the expansion rotor cavity of each expansion rotor housing along a respective longitudinal axis of each expansion rotor cavity. A set of adjacent combustion assemblies is attached to each one of the expansion rotor housings. Each one of the combustion assemblies includes a combustion chamber. An expansion rotor is mounted on the shaft in the expansion rotor cavity of each expansion rotor housing such that the elongated shaft extends through a centroidal axis of each expansion rotor. A fuel delivery system is attached to each one of the combustion assemblies for providing a supply of fuel to each one of the combustion chambers.