System and method for controlling an independent metering valve
AssigneeCaterpillar Inc.
InventorsJames A. Aardema, Douglas W. Koehler
Life of this patent
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Abstract
A system and method for controlling an independent metering valve operating in a hydraulic circuit determines a displacement command for one or more metering valves to provide desired flows through the metering valves and desired pressure drops across the metering valves. The system determines the displacement command based on a mode of operation of the hydraulic circuit and a velocity for a hydraulic device controlled by the hydraulic circuit. The system determines the displacement command further based on an amount of flow available to the hydraulic circuit. The system allows the hydraulic circuit to be electronically controlled thereby providing flexibility not found in conventional hydraulic control systems.
Claims11
A method for controlling a hydraulic circuit having a metering valve, the method comprising the steps of:
- determining a desired pressure drop across the metering valve;
- determining a displacement for the metering valve based on said desired pressure drop and said desired flow;
- actuating the metering valve based on said displacement to control the hydraulic circuit;
- determining an offset associated with the metering valve;
- and
- wherein said step of determining a displacement determines said displacement for the metering valve based on said desired flow, said desired pressure drop, and said offset.
In a system having a plurality of hydraulic circuits, each of the plurality of hydraulic circuits having at least one metering valve, a method for positioning a metering valve in one of the plurality of hydraulic circuits comprising the steps of:
- determining a pressure in each of the plurality of hydraulic circuits based on a load and a mode of operation associated with each of the plurality of hydraulic circuits;
- determining a pump pressure based on said pressure in each of the plurality of hydraulic circuits and said mode of operation associated with each of the plurality of hydraulic circuits;
- determining a pressure drop across the metering valve based on said pressure in the one hydraulic circuit, said pump pressure, and said mode of operation of the one hydraulic circuit;
- and
- determining a displacement command based on said pressure drop so that the metering valve is positioned appropriately based on the operation of the one hydraulic circuit.
Dependencies are inferred from the claim text.