Patent ID: 7484368

Claim:
A method of controlling an internal combustion engine boosting system of the type comprising an exhaust-driven turbocharger and a mechanically-driven supercharger in series with said turbocharger; said supercharger having rotors and a clutch operable in a first condition to transmit torque from a source of mechanical drive to an input of said supercharger in response to a positive input, and operable in a second condition to interrupt the transmission of torque from said source to said input of said supercharger; said supercharger having an inlet, an outlet and a bypass passage providing fluid communication between said inlet and said outlet, and a bypass valve disposed within said bypass passage and operable between an open position permitting flow through said bypass passage, and a closed position blocking flow through said bypass passage, said method being characterized by: (a) determining possible operation of said clutch in said first condition; and (b) commanding said bypass valve toward said closed position, forcing air through said supercharger from said inlet through said outlet; said air flow causing said supercharger rotors to rotate, thus rotating said input of said supercharger prior to said clutch operating in said first condition.