Georgia Institute of Technology | Marquette University | Milwaukee School of Engineering | North Carolina A&T State University | Purdue University | University of California, Merced | University of Illinois, Urbana-Champaign | University of Minnesota | Vanderbilt University

Fluid Power Innovation & Research ConferenceMinneapolis, MN | October 10 - 12, 2016

Four-Quadrant Multi-Fluid Pump/Motor

John Lumkes, PhDPurdue University

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Project Overview / Title Major Objectives/Deliverables

Next Steps

• What are your research goals?• Design, Simulate, and Evaluate the

Feasibility of Mechanically Actuated Multi-fluid Pump/Motors

• How does this project fit into the CCEFP’s overall research strategy?

• Efficiency, Effectiveness, Environment • What is the original contribution of this

project?• Novel mechanical control of digital

pump/motors• What is the competing research or

methods? Why / what makes this technology better than the competition? What has been done in the past?

• Improvement of conventional units, other digital pump/motors (DPM)

• Efficiency, Controllability, Fluids• Electrical valve control for DPM

• What is planned for the next six months to one year?

• Develop the simulation and analyze test data for pump prototype

• How can industry help / contribute? • Component support/sponsorship

• Analyze test results from mechanically actuated pump

• Modify current digital pump/motor model and validate model using pump

• Simulate and design mechanical control four-quadrant pump/motor

• Experimentally test

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MotivationMotivation

• In the United States– 2-3% of the energy transferred by fluid power– More than $50B/year, 7-8% of total CO2– Mobile systems average 22% in efficiency

• Pump improvement impacts systems– Pumps are ubiquitous in fluid power systems– Max system efficiency ~ pump efficiency– Smarter systems and configurations require better

pumps to maximize effectiveness

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Research Outline

Cam Types

Valve Configuration

Implementation

Valve Improvement (Testing valves and incorporating 1E.6)

Control Algorithms(Mode Switching and Valve Timing)

Sensor Reduction

Four-QuadrantMulti-Fluid Pump/Motor

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AdvantagesAdvantages

• Advantages over state-of-the-art units◦ Eliminate valve plate losses◦ Leakage scales closely with

displacement◦ Pumping of non-conventional fluids

(water)

• Advantages over other digital units in literature

◦ On/Off valves can open against high pressure Freedom in operating strategies Four quadrant operation

◦ Self starting in motoring Digital displacement control

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AdvantagesDisadvantages

• Disadvantages(Electrically Actuated Valves)

◦ Additional electrical power consumption for valves

◦ Flow area of valves is less than traditional port plates

◦ Valve timing is critical for efficiency◦ Requires additional sensors and

embedded controls

Digital displacement control

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Operating Strategies

Digital displacement control

◦ Flow Diverting Excess flow taken into the

chamber is diverted back to the low pressure port

◦ Flow Limiting Amount of flow taken into the

chamber is limited to the desired flow

◦ Sequential (Diverting or Limiting)

Individual cylinders are operated at full or zero displacement

4

20 BarInlet

320 BarOutlet

Valve 1 Valve 2

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Operating Strategies

Digital displacement control

◦ Flow Diverting Excess flow taken into the

chamber is diverted back to the low pressure port

◦ Flow Limiting Amount of flow taken into the

chamber is limited to the desired flow

◦ Sequential (Diverting or Limiting)

Individual cylinders are operated at full or zero displacement

4

20 BarInlet

320 BarOutlet

Valve 1 Valve 2

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Simulation Model• Matlab Simscape

– Physics Based Modeling

• Piston, cylinder, valve– Includes compressibility– Considers effect of valve losses– Considers leakage between piston

and cylinder– Includes valve throttling losses– Includes valve electrical

consumption

Simulation Model

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Simulation Model

Simulation Results

Errors in valve delay, 1ms transition Effect of valve transition, 1ms delay

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Experimental Test StandMulti-piston digital pump/motor test stand

• 3-piston digital pump/motor

• Two on/off valves per piston

• Three 2,000 Hz pressure transducers

• Check valve

• Two accumulators

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Research Outline

Cam Types

Valve Configuration

Implementation

Valve Improvement (Testing valves and incorporating 1E.6)

Control Algorithms(Mode Switching and Valve Timing)

Sensor Reduction

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Operating Strategy State Analysis

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Mechanically Actuated Valves(MAV)

Advantages of cam driven valves:o Fast actuationo Consistento No electrical energy neededo Less complex controls and data

acquisitiono Most spring energy will be

recovered in closing

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Cam Types

Simulation

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Cam TypesSimulation Key Variables

Compression Angle: amount of shaft rotation needed to decompress the fluid

Transition Angle: amount of degrees to transition from closed to open valve state or vice versa

o Affects cam pressure angle

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Cam ProfilesSimulation Results

1000

psi

2000

psi

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Cam Phasing

Planetary

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ImplementationRadial Piston Pump

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Implementation

Inline Piston Pump

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Prototype (+video)

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• Prototype Pump Mechanism ready to test on existing digital pump/motor test stand

• Simulation study continuing (PumpLinx)• Next steps flow out of this intersection of test

data and simulation study

Summary