Viscous fan drive system logic
August 31, 2015. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3568647 Pulse control of an electro magnetically actuated viscous fluid coupling Selectively operable fan drive arrangement 4348991 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 InventorsApplicationNo. 522025 filed on 08/31/1995US Classes:192/58.61, Magnetic or electric123/41.12, Temperature-responsive192/58.62, Temperature and speed192/82T, Temperature operator192/103RSpeed responsiveExaminersPrimary: Lorence, Richard M.Attorney, Agent or FirmInternational ClassF16D 035/02AbstractA 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. | |
