Fixed displacement hydraulic pump match flow demand control system

A fixed displacement hydraulic pump match flow demand control system, the system comprising:

• a spool valve including,
• a hydraulic manifold, the hydraulic manifold including a chamber having a first end and a second end, the hydraulic manifold having a first input port and at least one second input port, each first input port and the at least one second input port passing through the hydraulic manifold into the chamber, the hydraulic manifold further having a first output port and at least one second output port, each first output port and the at least one second output port passing from the chamber through the hydraulic manifold, the hydraulic manifold further having a control port passing through the hydraulic manifold to the first end of the chamber and a feedback port passing through the housing to the second end of the chamber, and
• a spool received within the chamber having a first end and second end, the spool configured to shuttle within chamber based at least in part on a pressure difference between the first end and the second end of the chamber, the spool valve including a plurality of blocking sections configured to block at least a portion of at least one of the first output port and the at least one second output port based on a spool location within the chamber, the spool further including a plurality of connection sections positioned to space the plurality of the blocking sections,
• a first fixed displacement pump, an output of the first fixed displacement pump in fluid communication with the first input port of the hydraulic manifold;
• at least one second fixed displacement pump, an output of the at least one second fixed displacement pump in fluid communication with the at least one second input port of the hydraulic manifold;
• at least one line passage to a hydraulically operated device, each line passage of the at least one line passage being in fluid communication with an associated output port of the spool valve;
• at least one return passage in fluid communication with an associated output port of the of the spool valve;
• a line feedback passage in fluid communication with the feedback port and the at least one line passage, line pressure from the line feedback passage generating a line pressure force on the second end of the spool within the chamber
• a control valve in fluid communication with the control port of the spool valve, the control valve configured to provide a select bias pressure that generates a select bias force on the first end of the spool within the chamber to adjust a location of the spool in the chamber to achieve a desired line pressure in the at least one line passage;
• and
• a controller configured to provide a signal to the control valve relating to a desired line pressure.

A method of operating a fixed displacement hydraulic pump match flow demand control system, the method comprising:

• directing a first fluid flow from a first fixed displacement pump to a first input of a first pump spool gallery formed with a spool within a chamber of a housing of a spool valve;
• directing at least one second fluid flow from at least one second fixed displacement pump to at least one second input to at least one second pump spool gallery formed with the spool within the chamber of the housing of the spool valve;
• adjusting a bias pressure based on a received signal that indicates a desired line pressure to move the spool in the chamber of the housing of the spool valve, the bias pressure being in fluid communication with a pressure control spool gallery formed by an end of the spool within the chamber of the housing of the spool valve, wherein a fluid flow of at least one of a first output from the first pump spool gallery and at least one second output from the at least one second pump spool gallery is based on a position of the spool within a cavity of the housing of the spool valve, the first output and the at least one second output being in fluid communication with a hydraulically operated device;
• and
• preventing backflow in a line passage that is in fluid communication between the at least one second output and the hydraulically operated device with a check valve.

A method of operating a fixed displacement hydraulic pump match flow demand control system, the method comprising:

• directing a first fluid flow from a first fixed displacement pump to a first input of a first pump spool gallery formed with a spool within a chamber of a housing of a spool valve;
• directing at least one second fluid flow from at least one second fixed displacement pump to at least one second input to at least one second pump spool gallery formed with the spool within the chamber of the housing of the spool valve;
• and
• adjusting a bias pressure based on a received signal that indicates a desired line pressure to move the spool in the chamber of the housing of the spool valve, the bias pressure being in fluid communication with a pressure control spool gallery formed by an end of the spool within the chamber of the housing of the spool valve, wherein a fluid flow of at least one of a first output from the first pump spool gallery and at least one second output from the at least one second pump spool gallery is based on a position of the spool within a cavity of the housing of the spool valve, the first output and the at least one second output being in fluid communication with a hydraulically operated device;
• and
• directing fluid flow not needed from the first fixed displacement pump and the at least one second displacement pump to one or more return passages with the spool of the spool valve.