A fluid circulation system in accordance with the invention includes a first fluid utilizing device (12) requiring a minimum fluid flow having an input (14) for receiving the minimum flow and an output (16) for discharging fluid received from the input; a second fluid utilizing device (24) having an input (26) for receiving fluid and an output (31) for outputting fluid; and a valve (80) having a first input (32) for receiving the fluid flow flowing from the output of the second device, a first output (36) for supplying the minimum fluid flow to the first device, a second input (34) for receiving the fluid flow flowing from the output of the first device and a second output (38) for supplying the fluid flow to the second device wherein any deficiency in fluid flow below the first fluid flow flowing from the first input to the first output is supplied with additional fluid flow (102) from the second input to the first output with any remaining fluid flow (104) from the second input flowing from the second output.
The present invention meets these objectives providing an IDG hydraulic system that utilizes in flow series arrangement a scavenge pump, a spool valve and a boost pump. When spool valve detects an interruption in the supply pressure to the boost pump due to an adverse "g" condition, it reconfigures the system to a closed loop system. In this mode, the oil returning from the CVT is re-circulated back to the boost pump instead of back to the scavenge pump. Oil lost to leakage is replenished by an oil accumulator that use the gas pressure in the IDG's casing to expel fluid from the accumulator into the recirculating flow.
An hydraulic control system for an IDG includes in flow series arrangement a scavenge pump, a spool valve and a boost pump. When the spool valve detects an interruption in the supply pressure to the boost pump due to an adverse "g" condition, it reconfigures the system to a closed loop system. In this mode, the oil returning from the CVT is re-circulated back to the boost pump instead of back to the scavenge pump. A small accumulator of oil is used to make up for leakage in the system.
