Solenoid concept for pump control of a variable displacement piston pump

A system for controlling displacement of a hydraulic fluid pumped by a variable-displacement hydraulic pump, the system comprising:

• a variable-displacement hydraulic pump having a hydraulic input port and a hydraulic output port, the variable-displacement hydraulic pump configured to pump hydraulic fluid from a hydraulic fluid reservoir in fluid communication with the hydraulic input port to a load in fluid communication with the hydraulic output port;
• a mechanical control mechanism configured to control displacement of hydraulic fluid pumped from the hydraulic input port to the hydraulic output port of the variable-displacement hydraulic pump;
• a first electro-hydraulic solenoid valve having input and output hydraulic ports in fluid communication with the hydraulic output port and the hydraulic control port of the variable-displacement hydraulic pump, respectively, thereby regulating fluid conductivity therebetween;
• a second electro-hydraulic solenoid valve having input and output hydraulic ports in fluid communication with the hydraulic control port and the hydraulic input port of the variable-displacement hydraulic pump, respectively, thereby regulating fluid conductivity therebetween, wherein such regulation of fluid conductivity as performed by first and second electro-hydraulic solenoid valves controls fluid displacement through the variable-displacement hydraulic pump;
• a transducer configured to measure a metric of the variable-displacement hydraulic pump;
• an electronic control unit in conductive communication with the transducer and the first and second electro-hydraulic solenoid valves, the electronic control unit configured to generate and transmit electrical control signals to the first and second electro-hydraulic solenoid valves so as to control the metric measured to within a predetermined control band about a target value;
• and
• a hydraulic control piston within a hydraulic control cylinder having a hydraulic chamber in fluid communication with the hydraulic control port, the hydraulic control piston mechanically coupled to the mechanical control mechanism of the variable-displacement hydraulic pump so as to advance a position of the mechanical control mechanism in response to increasing pressure of hydraulic fluid received at the hydraulic control port.