Automatic calibration of remote hydraulic valve flow
AssigneeCase Corporation
InventorsYanming Hou, Guy T. Stoever, David E. Susag
Life of this patent
Estimating the term…
Abstract
A computer calibration method and apparatus for calibrating one or more auxiliary hydraulic valves on a work vehicle includes the steps of selecting a first auxiliary hydraulic valve, applying a valve opening signal to that valve, measuring a pressure in a flow restricted signal circuit coupled to the valve, comparing the first pressure with a predetermined pressure to see if the valve is cracked open and if the valve is not cracked open, incrementing the signal to a second level and repeating the foregoing steps until the first valve cracks open. The final step is saving a value indicative of the signal at which the valve just cracked open.
Claims11
A computer calibration method for calibrating a plurality of auxiliary hydraulic proportional control valves in a bi-directional flow control circuit in a work vehicle, wherein the inlet of each of the plurality of valves is provided with pressurized hydraulic fluid from a common source and wherein the outlet of each of the plurality of valves is fluidly coupled to a common load sensing circuit and is also configured to be fluidly coupled to an implement, and further wherein the load sensing circuit is fluidly coupled to the common source to control the specific hydraulic fluid output of the common source, and further wherein all of the plurality of valves are driven by an electronic controller that is configured to generate an electrical signal proportional to a desired degree of opening of each of the plurality of valves, the computer method comprising the steps of:
- (a) selecting a first valve of the plurality of valves;
- (b) applying a signal to the first valve equivalent to a first degree of desired valve opening;
- (c) measuring a first pressure in the load control circuit;
- (d) comparing the first pressure with a predetermined pressure to identify a change in pressure indicative of the first valve opening;
- (e) incrementing the signal to a second desired degree of valve opening greater than the first degree of valve opening if the step of comparing does not indicate that the first valve has opened;
- (f) repeating steps (b)-(e) until the first valve opens;
- (g) saving a value indicative of the signal.
An auxiliary hydraulics system for a work vehicle, comprising:
- a plurality of auxiliary hydraulic proportional control valve assemblies;
- a common load sensing circuit coupled to the plurality of valve assemblies and configured to generate a load control signal indicative of a composite hydraulic load;
- a common hydraulic source coupled to each of the plurality of valve assemblies and having a variable specific hydraulic fluid output;
- at least one microprocessor configured to generate a valve opening signal and to selectively apply the valve opening signal to each of the plurality of valve assemblies wherein the at least one microprocessor is further configured to
- (a) select a first valve of the plurality of valve assemblies;
- (b) apply a signal to the first valve equivalent to a first degree of desired valve opening;
- (c) measure a first pressure in the load sensing circuit;
- (d) compare the first pressure with a predetermined pressure to identify a change in pressure indicative of the first valve opening;
- (e) increment the signal to a second desired degree of valve opening greater than the first degree of valve opening if the step of comparing does not indicate that the first valve has opened;
- (f) repeat steps (b)-(e) until the first valve opens;
- and then
- (g) save a value indicative of the signal.
A work vehicle comprising:
- a chassis;
- a plurality of drive wheels disposed to support the chassis;
- an engine drivingly engaged to the drive wheels;
- a hydraulic pump engaged to and driven by the engine, the pump having a variable specific displacement that responds to at least one signal indicative of hydraulic load;
- a plurality of hydraulic proportional control valves that are disposed to regulate flow between the pump and at least one manifold and are driven by a corresponding plurality of valve signals;
- a plurality of valve driver circuits coupled to the plurality valves to drive the valves;
- an auxiliary hydraulic valve controller including at least one microprocessor that is coupled to the plurality of valve drivers and is configured to generate the plurality of valve signals, wherein the microprocessor is configured to sequentially drive each of the plurality of valves to successive valve positions until each valve is just cracked open as indicated by a pressure fluctuation on a load sensing signal line, and to save a value indicative of that cracked open position in a computer memory as a offset calibration value.
Dependencies are inferred from the claim text.