Abstract: This invention relates to a coaxial rotary engine. It has a stationary central cylindrical wall that supports and holds compressing and exhaust gates that open and close at the right time without direct human or electronic help, coaxial rotors with long, arcuate pistons that contain compressing chambers equipped with automatic inlet and outlet ports, compact combustors that do not require turbines, an automatic ignition system that fires at the proper moment, air passageway that runs through its center for internal cooling. It has no internal gears, nor off-centered rotors, nor reciprocating pistons, nor crankshaft. It burns gasoline amid ample air and at a comparatively low temperature, and consequently its exhausts contain extremely small amount of CO, NO.sub.x, and other pollutants. It could also burn hydrogen, hydrogen peroxide 80+, and other fuels.

Abstract: This invention relates to a rotary engine that functions without internal gears, off-centered rotors, reciprocating pistons, crankshafts, trochoidal chamber, chains, nor belts. (While no claim can be made on missing parts, the fact that such conventional parts are missing is one of the reasons that make this invention different from prior arts, and, therefore, it is so listed.) The preferred embodiment, comprising multipurpose rotors, paired dams, combustors, turbines, etc., could be made small enough to run a lawn mower or large enough to fly a big air plane. It uses a modified form of combustors, wherein combustion takes place amid ample air, thus promoting a fuller combustion of fuel at a lower temperature than in conventional rotary and reciprocating piston engines. Consequently, this invention has a surprisingly low amount of CO, NO.sub.x, and unburnt hydrocarbons in its exhausts.