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Free Piston Hydraulic Pump

2021

 

2020

Modeling Scavenging for a Hydraulic Free-Piston Engine Modeling Scavenging for a Hydraulic Free-Piston Engine
https://digitalcommons.macalester.edu/cgi/viewcontent.cgi?article=1138&context=mjpa

Control of dual hydraulic free piston engine | Request PDF
www.researchgate.net publication 264814143_Contro...

First Cycles of the Dual Hydraulic Free Piston Engine ...
www.researchgate.net Home Engines

2019

Independent Pressure and Flow Rate Control Enabled by Hydraulic Free Piston Engine
https://ieeexplore.ieee.org/document/8675501

Study on HCCI combustion improvement by using dual assisted compression ignition (DACI) on a hydraulic free piston engine fueled with methanol fuel
https://www.x-mol.com/paper/5994371?recommendPaper=1358608979407446016

 

2018

Energy and exergy analysis of hydraulic free-piston engines
https://trid.trb.org/view/1651092

Control and Influence of Valve Condition on Compression Stroke of Hydraulic Free Piston Engine
https://digital-library.theiet.org/content/conferences/10.1049/cp.2018.0099
and
https://ieeexplore.ieee.org/document/8491942

Free Piston Engine-Pump/Hydrostatic Motor Control Concepts
https://arc.aiaa.org/doi/pdf/10.2514/6.1987-9021

Research to Watch: Free Piston Engine Based Off-Road Vehicles
https://fluidpowerjournal.com/research-watch-free-piston-engine-based-off-road-vehicles/

Methods and systems for free piston engine control
https://patents.google.com/patent/US20130298874A1/en

Internal Combustion Type Free Piston Device Supplies Motive Fluid To Motor
https://patents.justia.com/patents-by-us-classification/60/595

 

2017

Tribological characteristics of piston rings in a single-piston hydraulic free-piston engine
https://www.emerald.com/insight/content/doi/10.1108/ILT-01-2015-0011/full/html

Stability, Control, and Constraint Enforcement of Piston Motion in a Hydraulic Free-Piston Engine
https://ieeexplore.ieee.org/document/7587380

Free Piston Engine Pump with Virtual Crankshaft Controller Allows Greater Flexibility in Mobile Fluid Power Applications
https://erc-assoc.org/content/free-piston-engine-pump-virtual-crankshaft-controller-allows-greater-flexibility-mobile

Accumulator
https://patents.google.com/patent/US9790962

Reciprocating integral linear engine compressor
https://patents.google.com/patent/US9957958

 

2016

 

Design Approach and Dimensionless Analysis of a Differential Driving Hydraulic Free Piston Engine
http://papers.sae.org/2016-01-8091/

Three-Dimensional CFD Analysis of Semi-Direct Injection Hydraulic Free Piston Engine
http://papers.sae.org/2016-01-1018/

Free Piston Engine Based Mobile Fluid Power Source
http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2604432

Free Piston Engine (FPE) Hydraulic Pump
http://news.nfpahub.com/fluid-power-research-update-free-piston-engine-hydraulic-pump/

INGOCAR 170 mpg Hydraulic Hybrid with Free-Piston Engine
https://www.youtube.com/watch?v=rCXnsitCYhw

Free Piston Engine (FPE) Hydraulic Pump
http://news.nfpahub.com/fluid-power-research-update-free-piston-engine-hydraulic-pump/

Free Piston Engine Based Mobile Fluid Power Source
http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2604432

 

2015

 

Simulation Study of Hydraulic Differential Drive Free-piston Engine
http://papers.sae.org/2015-01-1300/

Free Piston Combustion Engine Design Analysis and Challenges
http://papers.sae.org/2015-32-0768/

Modeling Scavenging for a Hydraulic Free-Piston Engine Modeling Scavenging for a Hydraulic Free-Piston Engine
https://digitalcommons.macalester.edu/cgi/viewcontent.cgi?article=1138&context=mjpa

Hydraulic hybrid vehicle with safe and efficient hydrostatic operation
https://www.google.com/patents/US9032723

Integrated hydraulic hybrid drivetrain system      Eaton Corporation
https://www.google.com/patents/US8992379

Hydrostatic drive system     Hydac Technology Gmbh
https://www.google.com/patents/US8959905

 

2014

Active Motion Control of a Hydraulic Free Piston Engine
https://ieeexplore.ieee.org/document/6583998

The control of an opposed hydraulic free piston engine
]
The control of an opposed hydraulic free piston engine

High-efficiency linear combustion engine - Etagen, Inc.
http://www.google.com/patents/US8662029

Opposed piston internal combustion engine and method of operation thereof
ttp://www.google.com/patents/US8671681

 

2013

Hydraulic Free Piston Engine Enabled by Active Motion Control
https://asmedigitalcollection.asme.org/memagazineselect/article/135/06/S7/380225/Hydraulic-Free-Piston-Engine-Enabled-by-Active

Modeling and Control of Hydraulic Linear and Free-Piston Engines
http://deepblue.lib.umich.edu/bitstream/handle/2027.42/102345/kzaseck_1.pdf?sequence=1

Hydraulic internal combustion engines
https://patents.google.com/patent/US8596230

INGOCAR 170 mpg Hydraulic Hybrid with Free-Piston Engine
http://www.youtube.com/watch?v=rCXnsitCYhw

Transient Control of a Hydraulic Free Piston Engine
http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1841152

Modeling and Control of Hydraulic Linear and Free-Piston Engines
\http://deepblue.lib.umich.edu/bitstream/handle/2027.42/102345/kzaseck_1.pdf?sequence=1

CCEFP update: Hydraulics and free piston engines
http://www.mobilehydraulictips.com/ccefp-update-hydraulics-free-piston-engines/

Center For Compact and Efficient Fluid Power
Hydraulic Hybrid Passenger Vehicle Test Bed 3: Highway Vehicles
http://www.ccefp.org/sites/all/files/documents/Info_TB3_HHPV.pdf

Center For Compact and Efficient Fluid Power
Project 2B.3: Free Piston Engine Hydraulic Pump
http://www.ccefp.org/sites/all/files/documents/Info_2B.3_Free_Piston_Eng_Hyd.pdf

Miniature Free Piston Engine for Fluid Power Applications
http://license.umn.edu/technologies/20120199_miniature-free-piston-engine-for-fluid-power-applications

Active Motion Control of a Hydraulic Free Piston Engine
http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6583998

Free Piston Engine Hydraulic Pump 2B.3
http://www.ccefp.org/research/thrust-2-compactness/project-2b3

Semi-analytical modelling of a hydraulic free-piston engine
http://www.academia.edu/6077878/Semi-analytical_modelling_of_a_hydraulic_free-piston_engine

Extreme Power Free-Piston Engine
http://contest.techbriefs.com/2014/entries/machinery-automation-robotics/4509

Hydraulic internal combustion engines - Sturman Digital Systems
http://www.google.com/patents/US8596230

Hydraulic Hybrid Research
http://www.epa.gov/otaq/technology/research/research-hhvs.htm

Design and Modeling of a Novel Internal Combustion Engine with Direct Hydraulic Power Take-off
http://papers.sae.org/2013-01-1733/

For Excavators, Hydraulic Is the New Hybrid
http://enr.construction.com/products/equipment/2013/0506-for-excavators-hydraulic-is-the-new-hybrid.asp

A Hybrid That Has No Batteries
http://www.caranddriver.com/columns/a-hybrid-that-has-no-batteries

A serial hybrid concept
http://www.volumtran.com/Pages/VOLUMTRAN.aspx

The Chiron free piston hydraulic pump
http://www.innas.com/CFPE.html

Innas Hydrid Drive
http://www.innas.com/HD_main.html

Design and Modeling of a Novel Internal Combustion Engine with Direct Hydraulic Power Take-off
http://papers.sae.org/2013-01-1733/

Free Piston Engine Hydraulic Pump
http://www.ccefp.org/research/thrust-2-compactness/project-2b3

Active Motion Control of a Hydraulic Free Piston Engine
http://bit.ly/1wsSfTE

Hydraulic powertrain system
http://www.google.com/patents/US8449270

 

2012

 

On–off motion of a hydraulic free-piston engine
http://pid.sagepub.com/content/227/3/323.abstract

Study on Piston Motion Control Strategy of Single Piston Hydraulic Free-piston Engine
http://dl.acm.org/citation.cfm?id=2194316.2194335

Motion control of a hydraulic free-piston engine
http://bit.ly/1wsSgqM

Paired-piston linear engine
http://www.google.com/patents/US8091519

 

2011

 

Experimental Study on Hydraulic Free-Piston Diesel Engine
http://bit.ly/1rpRSD5

Flatness-Based High Frequency Control of a Hydraulic Actuator
http://dynamicsystems.asmedigitalcollection.asme.org/article.aspx?articleid=1415211

Stability Analysis of a Hydraulic Free Piston Engine With HCCI Combustion
http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1638866

A Comparative Study of Permanent Magnet Linear Alternator and Hydraulic Free-Piston Engines

http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1638333

 

2010

Center For Compact and Efficient Fluid Power
Project 2B.2: Miniature HCCI Free Piston Engine Compressor
http://www.ccefp.org/sites/all/files/documents/Info_2B.2_Mini_HCCI_FPE.pdf

Fluid dynamic modeling of a free piston engine with labyrinth seals
http://link.springer.com/article/10.1007%2Fs11630-010-0141-2

Experimental Study on Hydraulic Free Piston Diesel Engine
http://papers.sae.org/2010-01-2149/

Free-piston engine having variable stroke and method for operating a free-piston engine – Universal Motor Corp
http://www.google.com/patents/WO2010046120A1?cl=en

 

2009

 

Design approach for single piston hydraulic free piston diesel engines
http://link.springer.com/article/10.1007%2Fs11465-009-0069-y

A review of free-piston engine history and applications.
http://www.mikalsen.eu/papers/FPEreview.pdf

Hydraulic Hybrid Vehicle Energy Management System
http://papers.sae.org/2009-01-1772/

Hydraulic Hybrid Vehicle Energy Management System
http://papers.sae.org/2009-01-2834/

 

2008

 

HYDRAULIC DRIVE VEHICLES
http://www.designnews.com/article/7232-Hydraulic_Hybrid_Cars_No_Batteries_Required.php

LEDHO, a Linear Engine with Direct Hydraulic Output
http://www.dehyds.com/index.html

Modeling and Simulation of a Hydraulic Free Piston Diesel Engine
http://www.sae.org/technical/papers/2008-01-1528

Modeling and Simulation of a Hydraulic Free Piston Diesel Engine
http://papers.sae.org/2008-01-1528/

Developing a 10cc Single-Valve, Reverse Uniflow, 2S Engine
http://www.sae.org/technical/papers/2008-01-0953

Volumtran FPE Concept
http://www.volumtran.com/Pages/VOLUMTRAN.aspx

Four-Stroke Free Piston Engine
http://www.google.com/patents/US20080271711

Starting a compression ignition free piston internal combustion engine having multiple cylinders - Ford
http://www.google.com/patents/US6983724

Universal hybrid engine, compressor and pump, and method of operation
http://www.google.com/patents/US7373870

Internal combustion engine – Advanced Propulsion Technologies
http://www.google.com/patents/US7383796

Dynamic Mass Transfer Rapid Response Power Conversion System – Raytheon
http://www.google.com/patents/US7363887

 

2007

 

Introducing Hydraulic-Electric Synergy into Hybrid Transmission Using the Free-piston Engine Technology
http://papers.sae.org/2007-01-4112/

Internal combustion engine – Advanced Propulsion Technologies
http://www.google.com/patents/US7207299

Internal combustion engine – Advanced Propulsion Technologies
https://www.google.com/patents/US7255070

Rapid response power conversion device – Sarcos Investments
http://www.google.com/patents/US7210430

Four-cylinder, four-cycle, free piston, premixed charge compression ignition, internal combustion
reciprocating piston engine with a variable piston stroke
http://www.google.com/patents/US7258086

 

2006

 

EPA Hybrid Truck Initiative
http://files.harc.edu/Projects/Transportation/HydraulicHybridsGray.pdf

Control of dual hydraulic free piston engine
http://inderscience.metapress.com/content/27nae0bqtqkrkbb2/

Hydraulic synchronizing coupler for a free piston engine - Ford
http://www.google.com/patents/US7077080

Piston guides for a free piston engine - Ford
http://www.google.com/patents/US7032548

Starting a compression ignition free piston internal combustion engine having multiple cylinders  - Ford
http://www.google.com/patents/US6983724

Valve System For A Rapid Response Power Conversion Device – Sarcos Investments
http://www.google.com/patents/US7066116

Apparatus for determining free piston position and an apparatus for controlling free piston position – Global Cooling
http://www.google.com/patents/US7075292

 

2005

 

HYDRAULIC FREE PISTON ENGINE MAGAZINE ARTICLE
http://www.memagazine.org/backissues/membersonly/may05/departments/news_notes/news_note.html

Design, Development and Testing of Multi-Cylinder Hydraulic Free-Piston Engines
http://www.sae.org/technical/papers/2005-01-1167

Piston lubrication for a free piston engine – Ford
http://www.google.com/patents/US6971341

Piston stopper for a free piston engine - Ford
http://www.google.com/patents/US6973898

Fuel injection for a free piston engine - Ford
http://www.google.com/patents/US6959672

Opposed piston opposed cylinder free piston engine - Ford
http://www.google.com/patents/US6953010

Compression pulse starting of a free piston internal combustion engine having multiple cylinders - Ford
http://www.google.com/patents/US6966280

Compression pulse starting of a free piston internal combustion engine - Ford
http://www.google.com/patents/US6971340

Position sensing for a free piston engine - Ford
http://www.google.com/patents/US6948459

Air charging system for an opposed piston opposed cylinder free piston engine - Ford
http://www.google.com/patents/US6957632

Air scavenging for an opposed piston opposed cylinder free piston engine – Ford
http://www.google.com/patents/US6941904

Electromagnetic servo valve strategy for controlling a free piston engine - Ford
http://www.google.com/patents/US6971339


Exhaust gas recirculation for a free piston engine – Ford
http://www.google.com/patents/US6925971

Sodium cooled pistons for a free piston engine – Ford
http://www.google.com/patents/US6904876

Rapid response power conversion device – Sarcos Investments
http://www.google.com/patents/US6957631

Controllable combustion method and device – Sarcos Investments
http://www.google.com/patents/US6938588

Generic free-piston engine with transformer valve assembly for reducing throttling losses – Mannesmann Rexroth
http://www.google.com/patents/US6863507

Free piston engine – Bosch Rexroth
http://www.google.com/patents/US6931845

 

2004

 

Fundamental test results of a hydraulic free piston internal combustion engine
http://pid.sagepub.com/content/218/10/1149.abstract

Energy converter – Clavis Technology
http://www.google.com/patents/US6759755

Piston assembly for use in a free piston internal combustion engine - Caterpillar Inc
http://www.google.com/patents/US6694930

Free-piston unit for generating hydraulic energy – Innas Free Piston
http://www.google.com/patents/US6823671

 

2003

 

DESIGN, CONSTRUCTION, AND EXPERIMENTAL EVALUATION OF A
MONOPROPELLANT POWERED FREE PISTON HYDRAULIC PUMP
http://bit.ly/1CS2SzE

Fully-controlled, free-piston engine – U.S. EPA
http://www.google.com/patents/US6652247

Fully-controlled, free-piston engine – U.S. EPA
http://www.google.com/patents/US6582204

Cyclically operated fluid displacement machine –Lotus Cars
http://www.google.com/patents/US6626650

 

2002

 

Free piston engine system with direct drive hydraulic output - Caterpillar Inc.
http://www.google.com/patents/US6470677

Free piston internal combustion engine with pulse compression- Caterpillar Inc
http://www.google.com/patents/US6463895

Free-piston internal combustion engine
http://www.google.com/patents/US6484674

Piston Assembly For Free Piston Internal Combustion Engine - Caterpillar Inc.
http://www.google.com/patents/US6463903

 

2001

 

Performance Simulation of a Compression Ignition Free Piston Engine
http://papers.sae.org/2001-01-0280/

The development of the Innas free piston engine
http://bit.ly/16CwdnG

Method of operating a free piston internal combustion engine with high pressure hydraulic fluid upon misfire or initial
start-up – Caterpillar Inc
http://www.google.com/patents/US6206656

Free piston internal combustion engine with piston head functioning as a bearing
- Caterpillar Inc
http://www.google.com/patents/US6205961

Method of operating a free piston internal combustion engine with a short bore/stroke ratio - Caterpillar Inc
http://www.google.com/patents/US6314924

Free piston internal combustion engine
http://www.google.com/patents/US6293231

Free piston engine provided with a purging air dosing system - Innas Free Piston B.V.
http://www.google.com/patents/US6279517

Free piston internal combustion engine - Sunpower
http://www.google.com/patents/US6170442

Free piston internal combustion engine with pulse compression – Caterpillar Inc
http://www.google.com/patents/US6269783

Multi-piston hydraulic pump for a free piston engine – Sampower
http://www.google.com/patents/US6241488

Free piston internal combustion engine with piston head having non-metallic bearing surface – Caterpillar Inc
http://www.google.com/patents/US6216647

Free piston internal combustion engine with rotating piston – Caterpillar Inc
http://www.google.com/patents/US6244226

 

2000

 

Simulation of a Two-Stroke Compression Ignition Hydraulic Free Piston Engine
http://www.gtisoft.com/upload/HUT-Free-Piston.PDF

Horsepower with Brains: The Design of the CHIRON Free Piston Engine
http://papers.sae.org/2000-01-2545/

First Cycles of the Dual Hydraulic Free Piston Engine
http://papers.sae.org/2000-01-2546/

HYDRAULIC FREE PISTON ENGINE
http://www.icel.tkk.fi/research/Pulse_Two.html

Free piston internal combustion engine with piston head having a radially moveable cap – Caterpillar Inc
http://www.google.com/patents/US6164250

Method of operating a free piston internal combustion engine with a variable pressure hydraulic fluid output – Caterpillar Inc
http://www.google.com/patents/US6152091

Method for operation of a free piston engine – Caterpillar Inc
http://www.google.com/patents/US6135069

Method for operation of a free piston engine with pulse compression – Caterpillar Inc
http://www.google.com/patents/US6158401

Free piston internal combustion engine with rotating piston – Caterpillar Inc
http://www.google.com/patents/US6105541

Free piston engine – Split Cycle Technology Ltd
http://www.google.com/patents/US6029616

Free-piston internal combustion engine – Sunpower
http://www.google.com/patents/US6035637

Method for absorbing the vibration of a free-piston engine and vibration-absorbed free-piston engine –
Sampower
http://www.google.com/patents/US6135068

Injector system for free-piston engines
http://www.google.com/patents/US6050244

 

1999

 

Hydraulic switching valve, and a free piston engine provided therewith - Innas Free Piston B.V.
http://www.google.com/patents/US5983638

 

1998

 

The development of the Innas Free Piston Engine
http://bit.ly/19a1qib

Free piston internal combustion engine - Sunpower
http://www.google.com/patents/US5775273

Free-piston engine - Innas Free Piston
http://www.google.com/patents/US5829393

Computerized internal supercharged engine-pump
http://www.google.com/patents/US5813371

 

1997

 

Free piston internal combustion engine
http://www.google.com/patents/US5678522

 

1996

 

The Combustion Process in a DI Diesel Hydraulic Free Piston Engine
http://papers.sae.org/960032/

Free-piston engine having a fluid energy unit - Innas Free Piston B.V.
http://www.google.com/patents/US5556262

Free-piston engine having a slidable ring for moving the piston - Innas Free Piston B.V.
http://www.google.com/patents/US5482445

Method for the cold start of a free-piston engine; and free-piston engine adapted for use of this method -
Innas Free Piston B.V.
http://www.google.com/patents/US5540193

Reciprocating system
http://www.google.com/patents/US5540194

 

1995

 

Free-piston engine having a fluid pressure unit - Innas Free Piston B.V.
http://www.google.com/patents/US5473893

 

1994

 

A Review of Free Piston Engine Concepts
http://www.sae.org/technical/papers/941776

Vehicular drive system using stored fluid power for improved efficiency
http://www.google.com/patents/US5327857

Free piston engine control system – Tectonics Companies
http://www.google.com/patents/US5287827

Free piston internal combustion engine
http://www.google.com/patents/US5363651

 

1993

A Prime Mover Consists of a Free Piston Internal Combustion Hydraulic Power Generator and a Hydraulic Motor
http://papers.sae.org/930313/

 

1992

 

Design of a Free-Piston Engine-Pump
http://papers.sae.org/921740/

A Prime Mover Consists of a Free Piston Internal Combustion Hydraulic Power Generator and a Hydraulic Motor
http://papers.sae.org/930313/

Method and apparatus for starting a free piston combustion engine hydraulically - Sampower
http://www.google.com/patents/US5123245

 

1991

 

Silencer for Hydraulic Piston Pump Pressure Pulsations
http://papers.sae.org/911759/

Fluid power engine
http://www.google.com/patents/US5036667

Computer optimized hybrid engine
http://www.google.com/patents/US5002020

 

1990

 

Internal combustion engine with fluid drive output
http://www.google.com/patents/US4966000

Unsymmetrical free piston engine
http://www.google.com/patents/US4896632

 

1989

 

Internal combustion engine
http://www.google.com/patents/US4831972

Internal combustion engine, particularly, a free-piston engine
http://www.google.com/patents/US4803960

Free piston engine-pump propulsion system
http://www.google.com/patents/US4891941

 

1988

 

Design Feasibility of a Free Piston Internal Combustion Engine/Hydraulic Pump
http://papers.sae.org/880657/

A Free-Piston Engine Hydraulic Pump for an Automotive Propulsion System - GM
http://papers.sae.org/880658/

Free-piston motor with hydraulic or pneumatic energy transmission
http://www.google.com/patents/US4791786

 

1986

 

Oil pump with oscillating piston
http://www.google.com/patents/US4620836

Internal combustion hydraulic engine
http://www.google.com/patents/US4599861

 

1984

 

Hydraulic pump with variable-stroke piston and generator using said pump - Airmachines
http://www.google.com/patents/US4461613

Free piston engine pump with energy rate smoothing – Pneumo Corp.
http://www.google.com/patents/US4435133

 

1983

 

Hydraulic generator with free-piston engine – Regie Nationale des Usines Renault
https://www.google.com/patents/US4415313

Opposed piston type free piston engine pump unit – Pneumo Corp.
http://www.google.com/patents/US4382748

Free-piston engine pump
https://www.google.com/patents/US4369021

 

1982

 

Linear engine/hydraulic pump – Pneumo Corp.
http://www.google.com/patents/US4308720

Hydraulic engine
http://www.google.com/patents/US4326380

Internal combustion engine or pumping device
http://www.google.com/patents/US4362477

 

1981

 

A Free Piston Engine-Pump for an Automotive Propulsion System
http://papers.sae.org/810266/

Free piston engine pump including variable energy rate and acceleration-deceleration controls – Pneumo Corp.
http://www.google.com/patents/US4307999

 

1978

 

Free-piston engine-pump unit
http://www.google.com/patents/US4087205

Gas cushioned free piston type engine
http://www.google.com/patents/US4128083

Free-piston engine with opposed cylinders
http://www.google.com/patents/US4085711

 

1976

 

Resonant gas-expansion engine with hydraulic energy conversion
http://www.google.com/patents/US3932989

 

1973

 

The Braun Linear Engine
http://papers.sae.org/730185/

FREE PISTON ENGINE STARTING APPARATUS
http://www.google.com/patents/US3769950

 

1972

 

FREE PISTON ENGINE IGNITION APPARATUS
http://www.google.com/patents/US3643638

 

1971

 

BALANCED-FREE PISTON ENGINE
http://www.google.co.uk/patents/US3610217

 

1959

 

FORD FREE-PISTON ENGINE DEVELOPMENT
http://papers.sae.org/590045/

 

1958

 

The Future of the FREE-PISTON ENGINE in Commercial Vehicles - FORD
http://papers.sae.org/580032/

SIMULATION OF A FREE-PISTON ENGINE WITH A DIGITAL COMPUTER - GM
http://papers.sae.org/580267/

 

1957

 

THE AUTOMOTIVE FREE-PISTON-TURBINE ENGINE - FORD
http://papers.sae.org/570051/

Observations on 25,000 Hours of Free-Piston-Engine Operation - GM
http://papers.sae.org/570042/

THE GMR 4-4 “HYPREX” ENGINE A CONCEPT OF THE FREE-PISTON ENGINE FOR
AUTOMOTIVE USE - GM
http://papers.sae.org/570032/