Method for controlling the pitch angle of blades of an engine cooling fan

A method for controlling blades of a cooling fan associated with a radiator of an engine, the cooling fan including an axis and a central hub, the blades of the cooling fan extending radially from the central hub, a pitch angle of the blades being adjustable relative to a plane perpendicular to the axis between a minimum pitch angle and a maximum pitch angle at which the cooling fan supplies a greater quantity of air than when the blades are at the minimum pitch angle, the method comprising:

• determining one or more engine quantities related to the engine;
• determining a selected pitch angle for the blades of the cooling fan based at least in part on the one or more determined engine quantities, the selected pitch angle being greater than the minimum pitch angle;
• adjusting the pitch angle of the blades to the selected pitch angle;
• determining an engine speed;
• determining a first derivative of the engine speed to detect accelerations of the engine;
• and
• adjusting the pitch angle of the blades from the selected pitch angle to the minimum pitch angle when the determined first derivative exceeds a threshold value so that, during acceleration, energy drawn by the cooling fan is reduced.