Variable system pressure based on implement position
A hydraulic system for controlling an implement on a work machine may include a hydraulic reservoir, a hydraulic pump in fluid communication with the reservoir, a central valve in fluid communication with the pump and configured for controlling the implement, a load sense pressure relief system, and a controller. The controller may be configured for controlling the central valve and the load sense pressure relief system and selecting between operating the hydraulic system at a first pressure and a second pressure based on a factor relating to implement position.
1. A hydraulic system for controlling an implement on a work machine, comprising:
a hydraulic reservoir;
a hydraulic pump in fluid communication with the reservoir;
a central valve in fluid communication with the pump and configured for controlling the implement;
a pressure relief system; and
a controller configured for controlling the central valve and the pressure relief system and selecting between operating the hydraulic system at a first system pressure and a second system pressure based on a position of the implement, wherein:
the position of the implement comprises a threshold height, and
wherein the implement is a loader lift arm and bucket system wherein a bucket is pivotably coupled to a lift arm at a pivot pin and the controller compares a height of the pivot pin to the threshold height.
2. The system of claim 1 , wherein the threshold height comprises a bottom limit and a top limit.
3. The system of claim 2 , wherein the bottom limit is selected to require the pivot pin to be above a reasonable dig height for the bucket.
4. The system of claim 3 , wherein the top limit is selected to require the pivot pin to be below a height where a lower pressure of the first and second system pressures is insufficient to maintain the bucket with a maximum payload.
5. A method of operating a hydraulic system, the method comprising:
operating a work machine and controlling an implement of the work machine with a hydraulic system;
monitoring a factor relating to implement position;
operating the hydraulic system at a first of a plurality of available system pressures unless and until the implement position dictates switching to a second of the plurality of available system pressures;
switching to the second pressure;
operating the hydraulic system at the second pressure unless and until the implement position dictates switching back to the first pressure, wherein the factor relating to implement position is a pin height of a bucket on a loader.
6. The method of claim 5 , wherein monitoring a factor relating to implement position comprises comparing the pin height to a bottom limit and a top limit.
7. The method of claim 6 , wherein the bottom limit is a height above which it is no longer reasonable to dig.
8. The method of claim 7 , wherein the top limit is a height below which the first pressure is sufficient to carry the maximum payload.
9. A work machine comprising:
an implement;
a hydraulic system for controlling the implement, comprising:
a hydraulic reservoir;
a hydraulic pump in fluid communication with the reservoir;
a central valve in fluid communication with the pump and configured for controlling the implement;
a pressure relief system; and
a controller configured for controlling the central valve and the pressure relief system and selecting between operating the hydraulic system at a first pressure and a second pressure based on a position of the implement, wherein the work machine comprises a loader and the implement is a lift arm and bucket system.