High power density and good controllability are the most appealing characteristics that make hydraulic systems the best choice for many applications. Current state of the art hydraulic variable displacement pumps show high efficiency at high displacement while they have poor efficiencies at low displacement. This paper proposes a novel alternating flow (AF) variable displacement hydraulic pump to 1) eliminate metering losses by acting as a high-bandwidth pump for displacement control, 2) achieve high efficiency across a wide range of operating conditions and displacements, and 3) allow multiple units to be easily common-shaft mounted for a compact multi-actuator displacement control system from a single prime-mover. A dynamic model using first principles describes the cylinder pressure, flows between pairs of cylinders, and net inlet and outlet flows as a function of the pump’s phase shift angle. The model captures hydraulic check valve dynamics, the effective bulk modulus, leakage flows, and viscous friction. Piston kinematics and dynamics are discussed and energy loss models are presented and used to guide the design for a first prototype of the AF hydraulic pump. The paper presents simulation results from the model that offer an initial evaluation of this novel pump concept and potential applications.
|Original language||English (US)|
|Title of host publication||ASME/BATH 2017 Symposium on Fluid Power and Motion Control, FPMC 2017|
|Publisher||American Society of Mechanical Engineers|
|State||Published - 2017|
|Event||ASME/BATH 2017 Symposium on Fluid Power and Motion Control, FPMC 2017 - Sarasota, United States|
Duration: Oct 16 2017 → Oct 19 2017
|Name||ASME/BATH 2017 Symposium on Fluid Power and Motion Control, FPMC 2017|
|Other||ASME/BATH 2017 Symposium on Fluid Power and Motion Control, FPMC 2017|
|Period||10/16/17 → 10/19/17|
Bibliographical noteFunding Information:
This project is sponsored by the Center for Compact and Efficient Fluid Power (CCEFP) under NSF grant #0540834 with funding from the National Fluid Power Association (NFPA) Education and Technology Foundation. We also thank Cat Pump® for donating the experimental prototype.
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