Abstract: A secondary air feeder for an internal combustion engine, including a vortex chamber provided between a carburetor and a suction pipe. The air supply to the vortex chamber is regulated by an air supply regulator, in which a valve is opened and closed in accordance with the engine speed.

Abstract: A rotary internal combustion engine includes a housing having trochoidal inner periphery, a substantially triangular rotor having three arch-like peripheral faces and rotatably mounted within the housing, a recess of substantially spoon-like shape provided in each of the peripheral faces of the rotor, a fuel port provided in the housing in communication therewithin, and an elongated air intake port provided in the side wall of the housing so as to be opened and closed by a side face of the rotor according to the rotation thereof. The air intake port is inclined upwardly in the direction of rotation of rotor, and is disposed at such a relative position that it gradually moves towards the rear end portion of a combustion chamber defined by the inner periphery of the housing and each of the peripheral faces of the rotor. To the air intake port, may be connected means for adjusting the air flow in response to the operating mode of the engine.