Patent ID: 8056543

Claim:
A supercharger comprising: a housing having a low-pressure inlet opening, a high-pressure outlet opening and an inner cavity having a plurality of cylindrical cavity portions defined by circumferentially extending housing walls, extending within the housing and fluidly connecting the low-pressure inlet opening and the high-pressure outlet opening; a plurality of lobed rotors, disposed for rotation in the cylindrical cavity portions, having lobes defining, in cooperation with the circumferentially extending housing walls of the cylindrical cavity portions, a plurality of low-pressure internal chambers configured to move low-pressure air from the low-pressure inlet opening to the high-pressure outlet opening of the housing during rotation of the lobed rotors; a sound attenuator, being associated with the housing and located adjacent to the high-pressure outlet opening, defining a tuner chamber therein; a plurality of circumferentially spaced tuner ports extending through the circumferentially extending walls of the cylindrical cavity portions to fluidly connect the tuner chamber of the sound attenuator with the inner cavity of the housing to define a Helmholtz-type resonator; and at least one land defined, by the circumferentially extending walls of the cylindrical cavity portions, extending between the circumferentially spaced tuner ports such that the high-pressure outlet opening and the plurality of low-pressure internal chambers are fluidly connected through the tuner chamber when a lobed rotor defining a low-pressure internal chamber is aligned with the land.