초록 ▼

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 p

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.

대표청구항 ▼

A method of controlling a viscous fluid coupling receiving input drive torque from an engine of a vehicle, and transmitting output drive torque to a radiator cooling fan, the viscous fluid coupling comprising an output coupling defining a fluid chamber, valve means operable to separate said fluid ch

A method of controlling a viscous fluid coupling receiving input drive torque from an engine of a vehicle, and transmitting output drive torque to a radiator cooling fan, the viscous fluid coupling comprising an output coupling defining a fluid chamber, valve means operable to separate said fluid chamber into a reservoir chamber and an operating chamber, an input coupling rotatably disposed in said operating chamber and operable to transmit input drive torque to said output coupling in response to the presence of viscous fluid in said operating chamber, said valve means including a valve member moveable between a closed position (FIG. 3A) blocking fluid flow into said operating chamber, and an open position (FIG. 3B) permitting fluid flow into said operating chamber, and actuator means operable to move said valve member between said closed position and said open position in response to changes in an input signal; said method comprising the steps of: (a) sensing the speed of the vehicle engine; (b) comparing said sensed engine speed to a first limit and to a second limit, and when said engine speed is greater than said first limit but less than said second limit; then (c) sensing the speed of rotation of said radiator cooling fan; (d) comparing said fan speed to a predetermined fan speed limit, and when said fan speed is greater than said predetermined fan speed limit; (e) modifying said input signal to move said valve member toward said closed position (FIG. 3A).