Patent ID: 7273032

Claim:
An internal combustion engine comprised of a pair of relatively moveable components defining combustion chamber that varies in volume cyclically as said components move, a pair of intake passages for supplying at least an air charge to said combustion chamber through respective valved openings communicating with said combustion chamber, a throttle valve in a common inlet to said intake passages controlling the air flow thereto, a pair of branch passage each formed in a respective one of said intake passages having an upstream inlet opening in communication with said common inlet and a discharge opening communicating directly with the valved opening of the respective of said intake passages in a direction to induce a swirling motion in the air delivered to said combustion chamber from said branch passages, and a control valve for precluding the flow through one of said branch passages when in a first position and permitting flow through both of said branch passages in a second position, said control valve comprising a butterfly valve supported for rotation about an axis extending transversely across said common inlet downstream of said throttle valve.