This work describes an efficient means to adjust the power level of an axial piston hydraulic pump/motor. Conventionally, the displacement of a piston pump is varied by changing the stroke length of each piston. Since the losses do not decrease proportionally to the displacement, the efficiency is low at low displacements. Here, with partial-stroke piston pressurization (PSPP), displacement is varied by changing the portion of the piston stroke over which the piston is subjected to high pressure. Since leakage and friction losses drop as the displacement is decreased, higher efficiency is achieved at low displacements with PSPP. While other systems have implemented PSPP with electric or cam-actuated valves, the pump described in this paper is unique in implementing PSPP by way of a simple, robust hydromechanical valve system. Experimental testing of a prototype PSPP pump/motor shows that the full load efficiency is maintained even at low displacements.
|Original language||English (US)|
|Title of host publication||ASME/BATH 2019 Symposium on Fluid Power and Motion Control, FPMC 2019|
|Publisher||American Society of Mechanical Engineers (ASME)|
|State||Published - 2020|
|Event||ASME/BATH 2019 Symposium on Fluid Power and Motion Control, FPMC 2019 - Longboat Key, United States|
Duration: Oct 7 2019 → Oct 9 2019
|Name||ASME/BATH 2019 Symposium on Fluid Power and Motion Control, FPMC 2019|
|Conference||ASME/BATH 2019 Symposium on Fluid Power and Motion Control, FPMC 2019|
|Period||10/7/19 → 10/9/19|
Bibliographical noteFunding Information:
This material is based upon work supported by the National Science Foundation under Grant #PFI-1700747 and through the Center for Compact and Efficient and Fluid Power (CCEFP) under Grant #EEC-0540834.
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