System and method for inhibiting saturation of a hydraulic valve assembly

A system for detecting and inhibiting saturation in a hydraulic valve assembly, the system comprising:

• a controller operable to receive commands and electronic signals and to output electronic signals;
• at least one operator input device coupled to the controller and operable to permit an operator of the system to input commands to the controller;
• a fluid pump operable to provide fluid in response to commands from the at least one operator input device;
• a plurality of fluid valves coupled to the controller and in fluid communication with the pump and operable to receive command signals from the controller responsive to commands inputted to the controller via the at least one operator input device;
• and
• a plurality of work elements in fluid communication with said plurality of fluid valves to receive fluid from the pump as controlled via the valves, wherein commands inputted to the controller via the at least one operator input device determine the amount of fluid flow to each of the work elements;
• said controller being programmed with an established margin pressure for the fluid pump and being further operable to perform a margin pressure check which includes determining the actual current margin pressure and comparing the actual current margin pressure to the established margin pressure and thereafter outputting appropriate signals to said plurality of fluid valves to enter a priority scheme changing fluid flow to said plurality of valves when the actual current margin pressure is less than the established margin pressure.

A method for detecting and inhibiting a saturation condition in a hydraulic system of a work machine wherein the hydraulic system includes a hydraulic pump for supplying fluid under pressure to the hydraulic system, a plurality of control valves for controllably passing fluid from the pump to a plurality of work elements, the method comprising the steps of:

• (a) providing at least one operator input device actuatable to control the operation of the work elements;
• (b) providing a controller coupled to the at least one operator input device for receiving signals therefrom, each signal from said at least one operator input device being indicative of a commanded fluid flow to at least one of the respective work elements, said controller outputting signals to the respective control valves to control the fluid flow to the respective work elements when said controller receives signals from said at least one operator input device indicative of a commanded fluid flow to the respective work elements;
• (c) determining an actual margin pressure of the pump in response to a comparison of the pump pressure with the pressure of the heaviest loaded work element requested through actuation of said at least one operator input device;
• (d) determining an established margin pressure of the pump;
• (e) comparing the actual margin pressure of the pump to the established margin pressure of the pump;
• (f) outputting appropriate signals to the control valves to limit fluid flow to the control valves when the actual margin pressure of the pump is less than the established margin pressure.

A method for controlling a hydraulic system of a work machine wherein the hydraulic system includes a hydraulic pump for supplying fluid under pressure to the hydraulic system, a plurality of control valves for controllably passing fluid from the pump to a plurality of work elements, the method comprising the steps of:

• determining an actual margin pressure associated with the system;
• determining an established margin pressure associated with the system;
• comparing the actual margin pressure to the established margin pressure;
• and
• controlling said hydraulic system in response to said comparison.

A control system for detecting a saturation condition in a hydraulic system of a work machine wherein the hydraulic system includes a hydraulic pump for supplying fluid under pressure to the hydraulic system, a plurality of control valves for controllably passing fluid from the pump to a plurality of work elements, the control system comprising:

• at least one operator input device actuatable to control the operation of the work elements;
• a controller coupled to said at least one operator input device and being operable to receive signals therefrom, each signal from said at least one operator input device being indicative of a commanded fluid flow to at least one of the respective work elements;
• said controller outputting signals to the respective control valves to control the fluid flow to the respective work elements when said controller receives signals from said at least one operator input device indicative of a commanded fluid flow to the respective work elements;
• memory means for storing parameters associated with the hydraulic system including an established margin pressure;
• said controller being operable to determine an actual margin pressure associated with the hydraulic system;
• and
• said controller being further operable to compare the actual margin pressure to the established margin pressure and detect said saturation condition in response to said comparison.