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Marquette University | Milwaukee School of Engineering | Purdue University | University of California, Merced | University of Illinois, Urbana-Champaign | University of Minnesota |
Vanderbilt University
A Linkage Driven Variable
Displacement Pump
Shawn Wilhelm, Post-doctoral Associate
University of Minnesota
Advisor: James Van de Ven
Industry/University Engagement Summit
June 6 – 8, 2016
photo
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Hydraulic Systems are
Inefficient• Low Efficiency of Fluid
Power Flow Control
– 50% Industrial
– 20% Mobile
• $20B wasted annually
• 150 MMT of CO2
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Axial Piston
Bent Axis
Losses In Existing Pumps
Do Not Scale
• Port plates lead to
high constant
leakage rates at a
given pressure
independent of
speed
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Variable Displacement
Mechanism
• Vary the stroke of a piston with no other
sliding joints
• Eliminate Port Plate
Pouliot, H. N., Delameter, W. R., and Robinson, C. W., 1977, "A Variable Displacment Spark-Ignition Engine," No. 770114, SAE International.
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Advantage of Linkage Pump
• High efficiency at low displacement
• Losses scale with displacement
1800rpm
5000 psi
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Linkage Concept
Input
Crank
Slider Link
Axis of
Slide
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Linkage Concept
Input
Crank
Slider Link
Axis of
Slide
Connecting Rod
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Linkage Concept
Input
Crank
Slider Link
Axis of
Slide
Connecting Rod
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Input
Crank
Slider Link
Axis of
Slide
Connecting Rod
Rocker
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Linkage Concept
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Input
Crank
Slider Link
Axis of
Slide
Connecting Rod
RockerAdjustable
Ground Pivot
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Linkage Concept
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Input
Crank
Coupler
Connecting RodSlider Link
Axis of
Slide
Adjustable
Ground PivotRocker
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Linkage Concept
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Input
Crank
Coupler
Slider Link
TDC
Adjustable
Ground Pivot
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Linkage Concept
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Input
Crank
Coupler
Rocker
Connecting RodSlider Link
Adjustable
Ground Pivot
Axis of
Slide
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Linkage Concept
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Linkage Pump Prototypes
5 Years of Prototype Development
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Pumping Mechanism
Linkage
Adjustable
Ground
Piston Crosshead
Bearing
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Linkage In Motion
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First Prototype Pump
500 psi, 180rpm, 8.75cc/rev
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Model Agrees with Experiment
Displacement (%)Crank Angle (rad)
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Second Generation Prototype
• Three cylinder
• 21MPa (3000 psi)
• 5kW
• 30Hz operating
speed
• Bearings in joints
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Renderingkj
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Prototype is Smooth & Quiet
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Pump Model: Pressure/Flow
Dynamics
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Experimental Results
10 Hz Operation
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Third Generation Pump
3500 psi, 1800 rpm, 11.5cc/rev, Multi-Fluid
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New Pump Mechanism
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Radial Cam Adjustable Linkage Pump
Same Benefits as Crankshaft:
• Constant Top Dead Center
• True Zero Displacement
• High Efficiency Joints
• Insignificant Leakage
Added Benefits:
• Control Ripple with Cam Profile
• Multi-Lobe
• Compact, Stiff, Lightweight
• Cam Drives Link, Not Piston
– Low Piston Side Load
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Cam Pump First Gen Prototype
Five Cylinder, 3 Lobe 66cc/rev 5000psi
80-120 RPM
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Efficiency Curves
• Even at low speed
operation, high
efficiencies are
achieved
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Double Shear Design
Complete
• Displacement
– 0-15cc/rev
• RPM
– Nominal 280 rpm
– Max 550 rpm
• Pressure
– Max 350 Bar
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Current Activities
• Creating a startup to bring the pump to
market
• Targeting low speed applications where
efficiency is key.
• Looking for funding sources
• Applying for June SBIR Solicitation
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How can industry help?
• The goal is commercialization
• Flexible to many methods of doing so
• Looking for industry assistance,
partnership, or direct licensure
• Trying to development a model for
commercialization of academic research in
the fluid power industry
– How might you envision this?
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Thank You