Patent ID: 8443921

Claim:
A method for increasing an operating efficiency of a powertrain in a vehicle having a grille opening, and a fan characterized by a predetermined size and capable of being selectively turned on and off, the method comprising: unrestricting the grille opening by selecting a fully opened position for an adjustable shutter arranged relative to the grille opening at or below a first predetermined vehicle speed, and turning the fan off, such that sufficient airflow is provided through the unrestricted grille opening to cool the powertrain; unrestricting the grille opening by selecting the fully opened position for the shutter above the first predetermined vehicle speed and at or below a second predetermined vehicle speed under a high powertrain cooling load, and turning the fan on, such that sufficient airflow is provided through the unrestricted grille opening to cool the powertrain; and partially restricting the grille opening by selecting an intermediate position for the shutter above the second predetermined vehicle speed, and turning the fan off, such that sufficient airflow is provided through the partially restricted grille opening to cool the powertrain; wherein the predetermined size of the fan together with said selecting one of the fully opened and intermediate positions of the shutter at the respective predetermined vehicle speeds increase the operating efficiency of the powertrain.