Viscous fan drive system logic
US5584371A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 1995 |
| Grant date | Dec 17, 1996 |
| Priority date | — |
| Expiry date | Aug 31, 2015 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF01P2025/64
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A 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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.