Engine- and vehicle- speed-based engine cooling fan control

An engine cooling fan control in a motor vehicle powered by a heat engine having an engine cooling fan coupled to the engine through an interface that is operable to selectively place the cooling fan in driven and non-driven relationship with the engine, and a control system that, with the engine running, controls the interface to place the cooling fan selectively in driven relationship with the engine for forcing ambient air to contribute to engine cooling and in non-driven relationship with the engine to discontinue forcing ambient air to contribute to engine cooling, the engine cooling fan control comprising:

• a strategy in the control system for indicating when engine speed exceeds a reference engine speed, for indicating when vehicle speed exceeds a reference vehicle speed, and for indicating when rate of change of engine speed exceeds a selected rate of change of engine speed, and
• for causing the interface to place the cooling fan in non-driven relationship with the engine when vehicle speed exceeding the reference vehicle speed is indicated coincident with indication of either engine speed exceeding the reference engine speed or rate of change of engine speed exceeding the selected rate of change of engine speed.