Patent ID: 6884050

Claim:
A Roots supercharger for an internal combustion engine comprising: a housing including a rotor cavity having a surrounding wall and opposite end walls, an inlet in one end wall and an outlet adjacent the opposite end wall; a pair of positive displacement rotors oppositely rotatable in the rotor cavity and having interleaved helical lobes twisted with equal and opposite helix angles of approximately 0.314 deg/mm and forming chambers adapted to carry air axially from the inlet to the outlet; the rotors having inlet and outlet end faces having face offsets wherein the outlet end faces are angularly offset from the inlet end faces by equal angles of greater than 60 degrees in directions opposite to directions of rotation of the rotors; and the rotor chambers having a rotational seal time of less than 67 degrees of rotation of the rotors between nominal closing of their connection with the inlet and nominal opening of their connection with the outlet.