US 12,286,967 B2
High turn down ratio direct control for variable displacement pumps
Ryan Prescott Susca, Windsor, CT (US); and Ryan Shook, Loves Park, IL (US)
Assigned to Hamilton Sundstrand Corporation, Charlotte, NC (US)
Filed by Hamilton Sundstrand Corporation, Charlotte, NC (US)
Filed on Jan. 13, 2023, as Appl. No. 18/096,932.
Prior Publication US 2024/0240630 A1, Jul. 18, 2024
Int. Cl. F04B 49/08 (2006.01); F04B 49/24 (2006.01); F04B 53/10 (2006.01)
CPC F04B 49/08 (2013.01) [F04B 49/24 (2013.01); F04B 53/10 (2013.01); F04B 2201/06 (2013.01); F04B 2205/05 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A system comprising:
a variable displacement pump (VDP) in fluid communication with an inlet line and with an outlet line, wherein the VDP includes a variable displacement mechanism configured to vary pressure to the outlet line;
a bypass valve (BPV) including:
a BPV inlet in fluid communication with the outlet line; and
a BPV outlet in fluid communication with a bypass line that feeds into the inlet line upstream of the VDP;
an actuator operatively connected to control the BPV to vary flow from the BPV inlet to the bypass line; and
a controller operatively connected to the actuator to control recirculation flow passed through the BPV based on requested flow from a downstream system supplied by the outlet line and based on a predetermined low threshold of flow through the VDP, wherein:
the actuator comprises a first electrohydraulic servo valve (EHSV) connected in fluid communication with the BPV by a first control line;
the first EHSV is connected in fluid communication with both the inlet line through a first connection line and with the outlet line through a second connection line;
the first EHSV is operatively connected to the controller for active control of the first EHSV and to thereby actuate the BPV;
the system further comprises a second EHSV connected in fluid communication with the variable displacement mechanism by a second control line for control of flow through the VDP;
the second EHSV is connected in fluid communication with the both the inlet line through a third connection line and the outlet line through a fourth connection line; and
the second EHSV is operatively connected to the controller for active control of the second EHSV and to thereby actuate the variable displacement mechanism.