Pulse control of an electro magnetically actuated viscous fluid coupling
Selectively operable fan drive arrangement
Automotive electric fan controlling device
Engine cooling system control apparatus
Cooling system for automotive engine or the like
Method and apparatus for controlling the output speed of a fluid friction clutch
Closed loop pulse modulated viscous fan control
Variable speed coupling system for cooling an engine
ApplicationNo. 522025 filed on 08/31/1995
US Classes:192/58.61, Magnetic or electric123/41.12, Temperature-responsive192/58.62, Temperature and speed192/82T, Temperature operator192/103RSpeed responsive
ExaminersPrimary: Lorence, Richard M.
Attorney, Agent or Firm
International ClassF16D 035/02
AbstractA method of controlling a viscous fluid coupling (15) in which, when the vehicle engine (E) is operating at low speeds, if the speed of rotation (SF) of the fan exceeds a predetermined speed limit (L3), the input signal (29) to the coupling is modified to move the valve member (49) toward a closed position (FIG. 3A). This action reduces the occurrence of an overfill condition, thus reducing undesired fan noise when the engine again accelerates. Another aspect of the invention is to sense the speed (SE) of the engine, and whenever the sensed speed (SE) is high enough that operation in an excess slip heat region (ESH) is possible, compare the demanded fan speed (29) 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.