System and Method for Controlling Hydraulic Fluid Flow

Abstract

A system and method for controlling fluid flow through a hydraulic valve in a work machine is disclosed. The system and method may include receiving an input command by a controller configured to control a fluid flow to an actuator, the input command generated by an input controller. The system and method may also include receiving a parameter indicative of pump flow by the controller, determining a first valve command corresponding to the input command and determining a second valve command based upon the parameter that achieves the fluid flow to the actuator corresponding to the first valve command.

What is claimed is: 
     
         1 . A method of controlling fluid flow in a work machine, the method comprising:
 receiving an input command by a controller configured to control a fluid flow, the input command generated by an input controller;   receiving a parameter indicative of pump flow by the controller;   determining a first valve command corresponding to the input command; and   determining a second valve command based upon the parameter that achieves the fluid flow to an actuator corresponding to the first valve command.   
     
     
         2 . The method of  claim 1 , wherein the first valve command and the second valve command are percentages of total available opening area of at least one orifice of at least one hydraulic valve. 
     
     
         3 . The method of  claim 2 , wherein determining a second valve command comprises increasing the percentage of total available opening area of the at least one orifice when a pump flow falls below a benchmark pump flow, the benchmark pump flow corresponding to the first valve command. 
     
     
         4 . The method of  claim 2 , wherein determining a second valve command comprises decreasing the percentage of total available opening area of the at least one orifice when a pump flow rises above a benchmark pump flow, the benchmark pump flow corresponding to the first valve command. 
     
     
         5 . The method of  claim 1 , wherein the first valve command is determined by referring to a look-up table. 
     
     
         6 . The method of  claim 1 , wherein the second valve command is determined by referring to a look-up table. 
     
     
         7 . The method of  claim 1 , wherein the parameter is determined by engine speed. 
     
     
         8 . The method of  claim 1 , wherein based upon the second valve command, the controller generates an output signal that is transmitted to the at least one hydraulic valve. 
     
     
         9 . The method of  claim 8 , wherein in response to the output signal, the fluid flow through at least one hydraulic valve is varied. 
     
     
         10 . A system for controlling fluid flow through a hydraulic valve in a work machine, the system comprising:
 an input controller to generate an input command;   a parameter determinator to determine pump flow of the work machine; and   a controller configured to receive the input command and the pump flow, the controller further configured to determine a first valve command corresponding to the input command and a second valve command based upon the pump flow that achieves the fluid flow to an actuator corresponding to the first valve command.   
     
     
         11 . The system of  claim 10 , further comprising at least one hydraulic valve at least indirectly connected to the controller, the at least one hydraulic valve configured to receive the first and second valve commands to control the fluid flow therethrough. 
     
     
         12 . The system of  claim 11 , wherein the at least one hydraulic valve is a non-compensated valve. 
     
     
         13 . The system of  claim 10 , further comprising a pump at least indirectly connected to an engine of the work machine, the pump also at least indirectly connected to at least one hydraulic valve. 
     
     
         14 . The system of  claim 13 , wherein the pump flow is determined by engine speed. 
     
     
         15 . The system of  claim 10 , wherein the second valve command is greater than the first valve command when the pump flow is below a benchmark pump flow corresponding to the first valve command. 
     
     
         16 . The system of  claim 10 , wherein the second valve command is lesser than the first valve command when the pump flow is above a benchmark pump flow corresponding to the first valve command. 
     
     
         17 . A work machine, comprising:
 an engine;   an input controller for generating a plurality of input commands;   a pump flow sensor for determining a pump flow; and   a controller in at least indirect communication with the input controller and the pump flow sensor, the controller configured to determine a first valve command corresponding to the plurality of input commands, the controller also configured to determine a second valve command that achieves a fluid flow to an actuator corresponding to the first valve command when variations in the pump flow occur, the first and the second valve commands used to control the fluid flow to the actuator through a hydraulic valve.   
     
     
         18 . The work machine of  claim 17 , wherein the work machine is a small track type tractor. 
     
     
         19 . The work machine of  claim 17 , wherein the fluid flow through the hydraulic valve to the actuator is independent of the pump flow. 
     
     
         20 . The work machine of  claim 19 , wherein by making the fluid flow to the actuator independent of the pump flow, performance of an implement controlled by the hydraulic valve is improved.