Control system and method for viscous coupling of a vehicle radiator fan

摘要

A method of controlling a viscous fluid coupling (15) in which, the speed (SE) of the engine is sensed, and whenever the sensed speed (SE) is high enough that operation in an excess slip heat region (ESH) is possible, the demanded fan speed (29) is compared to the lower limit (CHP) of the slip heat region. Whenever the demanded fan speed exceeds the limit, the input signal (29) to the coupling is modified to operate the coupling at a speed safely above or below the slip heat region (ESH) depending on the state of control inputs such as engine temperature.