Water cooled viscous fan drive

A fluid coupling assembly for use with an internal combustion engine of the type including an engine block defining an engine coolant cavity having a coolant inlet and a coolant outlet;

• said fluid coupling assembly including an input pulley adapted to transmit input torque to an input coupling assembly of a fluid coupling device, said fluid coupling device being disposed at least partially within said engine coolant cavity;
• said fluid coupling device including an output coupling member disposed within said input coupling assembly, and including means operable to transmit output torque to a radiator cooling fan;
• said fluid coupling device defining a fluid reservoir chamber, and said input coupling assembly and said output coupling member cooperating to define a fluid operating chamber, whereby torque is transmitted from said input coupling assembly to said output coupling member in response to the presence of viscous fluid in said fluid operating chamber;
• said input pulley being disposed forwardly of said fluid coupling device and said radiator cooling fan being disposed forwardly of said input pulley;
• characterized by:
• (a) valve means disposed to separate said fluid reservoir chamber from said fluid operating chamber;
• (b) said valve means defining a fluid inlet port and including a valve member operable between a closed position blocking fluid flow through said fluid inlet port, and an open position, permitting fluid flow from said fluid reservoir chamber to said fluid operating chamber;
• and
• (c) control means operable in response to an input signal to move said valve member between said closed position and said open position.