A study and comparison of frictional losses in free-piston engine and crankshaft engines

Abstract Friction work in free-piston engines is expected to be lower than in crankshaft engines due to the elimination of the crank mechanism. In this paper, friction mechanisms were reviewed and compared between a free-piston and crankshaft engine of similar size. The main friction mechanisms were identified to be the piston assembly including piston rings and piston skirt, valve train system, the crank and bearing system for the CSE, and the linear electric generator for the FPE. The frictional loss of each friction mechanism was estimated and discussed. A Stribeck diagram was used to simulate the piston ring friction during hydrodynamic lubrication, mixed lubrication, and boundary condition. It is found that the FPE doesn’t show advantage on piston ring friction force over the CSE, and the frictional loss from the piston ring is even higher. While the elimination of the crankshaft system reduces the frictional loss of the FPE, and the total friction loss of the FPE is nearly half of the CSE.

[1]  Changlu Zhao,et al.  Determination of TDC in a hydraulic free-piston engine by a novel approach , 2014 .

[2]  D. E. Richardson,et al.  Review of Power Cylinder Friction for Diesel Engines , 2000 .

[3]  R. Mikalsen,et al.  Performance simulation of a spark ignited free-piston engine generator , 2008 .

[4]  Jibin Hu,et al.  Semi-analytical modelling of a hydraulic free-piston engine , 2014 .

[5]  Frank Rinderknecht,et al.  The Free-Piston Linear Generator Potentials and Challenges , 2013 .

[6]  M. Vilenius,et al.  Control of dual hydraulic free piston engine , 2006 .

[7]  Chenheng Yuan,et al.  Friction characteristics of piston rings in a free-piston engine generator , 2017 .

[8]  Nigel N. Clark,et al.  Fundamental Analysis of a Linear Two-Cylinder Internal Combustion Engine , 1998 .

[9]  Takaji Umeno,et al.  Development of Free Piston Engine Linear Generator System Part 2 - Investigation of Control System for Generator , 2014 .

[10]  Dinu Taraza,et al.  Friction Losses in Multi-Cylinder Diesel Engines , 2000 .

[11]  R. Mikalsen,et al.  The design and simulation of a two-stroke free-piston compression ignition engine for electrical power generation , 2008 .

[12]  Li Yanxiao,et al.  Tribological Characteristics of Piston Ring in a Free-piston Engine for Linear Generator , 2014 .

[13]  Guohong Tian,et al.  Effect of closed-loop controlled resonance based mechanism to start free piston engine generator: Simulation and test results , 2016 .

[14]  Changlu Zhao,et al.  Experimental investigation of the cycle-to-cycle variations in combustion process of a hydraulic free-piston engine , 2014 .

[15]  Qianfan Xin,et al.  Diesel Engine System Design , 2011 .

[16]  Changlu Zhao,et al.  Stability analysis of hydraulic free piston engine , 2015 .

[17]  Tian Tian,et al.  Analysis of the Piston Ring/Liner Oil Film Development During Warm-Up for an SI-Engine , 1996 .

[18]  Zhengxing Zuo,et al.  Parameters coupling designation of diesel free-piston linear alternator , 2011 .

[19]  Jin Xiao,et al.  Simulation of a Two-Stroke Free-Piston Engine for Electrical Power Generation , 2008 .

[20]  Matti Vilenius,et al.  First Cycles of the Dual Hydraulic Free Piston Engine , 2000 .

[21]  Guohong Tian,et al.  Development and validation of a free-piston engine generator numerical model , 2015 .

[22]  Shenghao Zhou,et al.  SIMULATION ON DUAL HYDRAULIC FREE PISTON ENGINE , 2005 .

[23]  Researcher Seppo Tikkanen,et al.  HYDRAULIC FREE PISTON ENGINE-THE POWER UNIT OF THE FUTURE? , 1999 .

[24]  Guohong Tian,et al.  Development Approach of a Spark-Ignited Free-Piston Engine Generator , 2014 .

[25]  R. Mikalsen,et al.  Disturbance analysis of a free-piston engine generator using a validated fast-response numerical model , 2017 .

[26]  Dinu Taraza,et al.  A Simplified Friction Model of the Piston Ring Assembly , 1999 .

[27]  R. Mikalsen,et al.  Piston motion control of a free-piston engine generator: A new approach using cascade control , 2016 .

[28]  R. Mikalsen,et al.  An investigation into the free-piston engine concept and its potential for high efficiency and low emissions power generation , 2008 .

[29]  Tony Roskilly,et al.  Research on the intermediate process of a free-piston linear generator from cold start-up to stable operation: Numerical model and experimental results , 2016 .

[30]  A. F. Underwood.  THE GMR 4-4 “HYPREX” ENGINE A CONCEPT OF THE FREE-PISTON ENGINE FOR AUTOMOTIVE USE , 1957 .

[31]  R. Mikalsen,et al.  Recent commercial free-piston engine developments for automotive applications , 2015 .

[32]  Guohong Tian,et al.  An experimental investigation into the starting process of free-piston engine generator , 2015 .

[33]  Gem Vael,et al.  Horsepower with Brains - The design of the CHIRON Free Piston Engine , 2000 .

[34]  R. Mikalsen,et al.  A review of free-piston engine history and applications , 2007 .

[35]  Tony Roskilly,et al.  Research on the operation characteristics of a free-piston linear generator: Numerical model and experimental results , 2017 .

[36]  Anthony Paul Roskilly,et al.  Design and simulation of a two- or four-stroke free-piston engine generator for range extender applications , 2016 .

[37]  Valeri Golovitchev,et al.  Modeling the Effect of Injection Schedule Change on Free Piston Engine Operation , 2006 .

[38]  Yuxi Miao,et al.  Research on the Combustion Characteristics of a Free-Piston Gasoline Engine Linear Generator during the Stable Generating Process , 2016 .

[39]  Guohong Tian,et al.  A fast response free-piston engine generator numerical model for control applications , 2016 .

[40]  Chang-Ping Lee,et al.  Turbine-Compound Free-Piston Linear Alternator Engine. , 2014 .

[41]  François Lanzetta,et al.  Optimization of a dual free piston Stirling engine , 2007 .