An experimental study of a single-piston free piston linear generator

Abstract

Free piston linear generator (FPLG) is a promising range extender for the electrical vehicle with unparallel advantages, such as compact structure, higher system efficiency, and reduced maintenance cost. However, due to the lack of the mechanic crankshaft, the related piston motion control is a challenge for the FPLG which causes problems such as misfire and crash and limits its widespread commercialization. Aimed at resolving the problems as misfire, a single-piston FPLG prototype has been designed and manufactured at Shanghai Jiao Tong University (SJTU). In this paper, the development process and experimental validation of the related control strategies were detailed. From the experimental studies, significant misfires were observed at first, while the FPLG operated in natural-aspiration conditions. The root cause of this misfire was then identified as the poor scavenging process, and a compressed air source was leveraged to enhance the related scavenging pressure. Afterward, optimal control parameters, in terms of scavenging pressure, air-fuel equivalence ratio, and ignition position, were then calibrated in this charged-scavenging condition. Eventually, the FPLG prototype has achieved a continuous stable operation of over 1000 cycles with an ignition rate of 100% and a cycle-to-cycle variation of less than 0.8%, produced an indicated power of 2.8 kW with an indicated thermal efficiency of 26% and an electrical power of 2.5 kW with an overall efficiency of 23.2%.

Graphical abstract

Keywords

free piston linear generator (FPLG) / charged scavenging / engine control / misfire / stable operation

References

[1] Huang Z, Zhu L, Li A. . Renewable synthetic fuel: turning carbon dioxide back into fuel. Frontiers in Energy, 2022, 16(2): 145–149

[2] Kizu R, Okamura K, Toriba A. . Antiandrogenic activities of diesel exhaust particle extracts in PC3/AR human prostate carcinoma cells. Toxicological Sciences, 2003, 76(2): 299–309

[3] TheUnited States Environmental Protection Agency. Health and environmental effects of particulate matter. 2018–04–20, available at website of epa-gov

[4] Bahrampour H, Beheshti Marnani A K, Askari M B. . Evaluation of renewable energies production potential in the Middle East: confronting the world’s energy crisis. Frontiers in Energy, 2020, 14(1): 42–56

[5] Wang J. The number of public charging stations in China ranks the first in the world. Machinery and Electronics Business (Chinese version), 2018, 0(1): 28–28

[6] Sun Y, Liu X. Impact of mileage anxiety on intention to use pure electric vehicle. Journal of Wuhan University of Technology (Transportation Science and Engineering), 2017, 41(1): 87–91

[7] Habib S, Khan M M, Abbas F. . A framework for stochastic estimation of electric vehicle charging behavior for risk assessment of distribution networks. Frontiers in Energy, 2020, 14(2): 298–317

[8] Mikalsen R, Roskilly A P. The design and simulation of a two-stroke free-piston compression ignition engine for electrical power generation. Applied Thermal Engineering, 2008, 28(5–6): 589–600

[9] Jia B, Smallbone A, Zuo Z. . Design and simulation of a two- or four-stroke free-piston engine generator for range extender applications. Energy Conversion and Management, 2016, 111: 289–298

[10] Jia B, Zuo Z, Feng H. . Effect of closed-loop controlled resonance based mechanism to start free piston engine generator: simulation and test results. Applied Energy, 2016, 164: 532–539

[11] Zhang C, Sun Z. Trajectory-based combustion control for renewable fuels in free piston engines. Applied Energy, 2017, 187: 72–83

[12] Zhang C, Sun Z. Using variable piston trajectory to reduce engine-out emissions. Applied Energy, 2016, 170: 403–414

[13] Zhang C, Li K, Sun Z. Modeling of piston trajectory-based HCCI combustion enabled by a free piston engine. Applied Energy, 2015, 139: 313–326

[14] Lin M, Mou J, Chi C. . A space power system of free piston Stirling generator based on potassium heat pipe. Frontiers in Energy, 2020, 14(1): 1–10

[15] PaterasP R. US Patent, 1 657 641, 1928–01–31

[16] Mikalsen R, Roskilly A P. A review of free-piston engine history and applications. Applied Thermal Engineering, 2007, 27(14–15): 2339–2352

[17] Farmer H O. Free-piston compressor-engines. Proceedings–Institution of Mechanical Engineers, 1947, 156(1): 253–271

[18] NorenO BErwinR L. The future of the FREE-PISTON ENGINE in commercial vehicles. SAE Technical Paper: 580032, 1958 oi:10.4271/580032

[19] Peter A J, Achten J. A review of free piston engine concepts. SAE Transactions, 1994, 103: 1836–1847

[20] TikkanenSLammilaMHerranenM, . First cycles of the dual hydraulic free piston engine. SAE Technical Paper: 2000-01-2546, 2000

[21] Hibi A, Ito T. Fundamental test results of a hydraulic free piston internal combustion engine. Proceedings of the Institution of Mechanical Engineers. Part D, Journal of Automobile Engineering, 2004, 218(10): 1149–1157

[22] Zhao Z, Zhang F, Huang Y. . An experimental study of the cycle stability of hydraulic free-piston engines. Applied Thermal Engineering, 2013, 54(2): 365–371

[23] Li K, Zhang C, Sun Z. Precise piston trajectory control for a free piston engine. Control Engineering Practice, 2015, 34: 30–38

[24] JiaB. Analysis and control of a spark ignition free-piston engine generator. Dissertation for the Doctoral Degree. Newcastle: Newcastle University, 2016

[25] Clark N, Nandkumar S, Atkinson C. . Operation of a smallbore two-stroke linear engine. In: Proceeding of the Fall Technical Conference of the ASME Internal Combustion Engine Division, New York, USA: American Society of Mechanical Engineers, 1998, 31: 33–40

[26] FamouriPCawthorneW RClarkN, . Design and testing of a novel linear alternator and engine system for remote electrical power generation. In: IEEE Power Engineering Society 1999 Winter Meeting (Cat. No.99CH36233), New York, NY, USA: IEEE: 108–112

[27] Cawthorne W R, Famouri P, Chen J. . Development of a linear alternator-engine for hybrid electric vehicle applications. IEEE Transactions on Vehicular Technology, 1999, 48(6): 1797–1802

[28] CawthorneWFamouriPClarkN. Integrated design of linear alternator/engine system for HEV auxiliary power unit. In: IEEE International Electric Machines and Drives Conference (Cat. No.01EX485). Cambridge, MA, USA. IEEE: 267–274

[29] NandkumarS. Two-stroke linear engine. Dissertation for the Doctoral Degree. West Virginia: West Virginia University, 1998

[30] HoudyschellD. A diesel two-stroke linear engine. Dissertation for the Doctoral Degree. West Virginia: West Virginia University, 2000

[31] van BlariganP. Advanced internal combustion electrical generator. In: Proceedings of the 2001 DOE Hydrogen Program Review, Maryland, USA, 2002

[32] van BlariganPParadisoNGoldsboroughS. Homogeneous charge compression ignition with a free piston: a new approach to ideal Otto cycle performance. SAE Technical Paper: 982484, 1998

[33] WuJParadisoNvan BlariganP, . Homogeneous charge compression ignition free piston linear alternator. Office of Scientific and Technical Information (OSTI), 1998

[34] Woo Y, Lee Y J. Free piston engine generator: Technology review and an experimental evaluation with hydrogen fuel. International Journal of Automotive Technology, 2014, 15(2): 229–235

[35] MikalsenR. An investigation into the free-piston engine concept and its potential for high efficiency and low emissions power generation. Dissertation for the Doctoral Degree. Newcastle: Newcastle University, 2008

[36] FerrariCFriedrichH E. Development of a free-piston linear generator for use in an extended-range electric vehicle. In: Proceeding to EVS26 International Battery, Hybrid and Fuel Cell Electrical Vehicle Symposium, Los Angeles, USA, 2012

[37] Rinderknecht F, Kock F. A high efficient energy converter for a hybrid vehicle concept. World Electric Vehicle Journal, 2012, 5(2): 475–481

[38] KockFHaagJFriedrichH E. The free piston linear generator - development of an innovative, compact, highly efficient range-extender module. SAE Technical Paper: 2013-01-1727, 2013

[39] Kock F, Heron A, Rinderknecht F. . The free-piston linear generator potentials and challenges. MTZ Worldwide, 2013, 74(10): 38–43

[40] HaagJKockFChiodiM, . Development approach for the investigation of homogeneous charge compression ignition in a free-piston engine. SAE Technical Paper: 2013-24-0047, 2013

[41] KosakaHAkitaTMoriyaK, . Development of free piston engine linear generator system part 1 — investigation of fundamental characteristics. SAE Technical Paper: 2014-01-1203, 2014

[42] GotoSMoriyaKKosakaH, . Development of free piston engine linear generator system part 2–investigation of control system for generator. SAE Technical Paper: 2014-01-1193, 2014

[43] MoriyaKGotoSAkitaT, . Development of free piston engine linear generator system part 3–novel control method of linear generator for to improve efficiency and stability. SAE Technical Paper: 2016-01-0685, 2016

[44] WangD. Study of free piston linear generator’s stable operation. Dissertation for the Doctoral Degree. Beijing: Beijing Institute of Technology, 2015 (in Chinese)

[45] MaoJ. Numerical simulation and experimental study of free piston linear generator operation. Dissertation for the Doctoral Degree. Beijing: Beijing Institute of Technology, 2011 (in Chinese)

[46] YuanC. Design and characterization of a diesel free piston linear generator. Dissertation for the Doctoral Degree. Beijing: Beijing Institute of Technology, 2015 (in Chinese)

[47] Johansen T A, Egeland O, Aa Johannessen E. . Free-piston diesel engine timing and control — toward electronic cam- and crankshaft. IEEE Transactions on Control Systems Technology, 2002, 10(2): 177–190

[48] LiQ. Study of free piston linear generator. Dissertation for the Doctoral Degree. Shanghai: Shanghai Jiao Tong University, 2011 (in Chinese)

[49] Yang X, Wang Z, Zhu C. . Control system design of a free piston linear generator through LabVIEW. Internal Combustion Engine and Power System (Chinese Version), 2018, 35(01): 7–12 (in Chinese)

[50] Lin B, Xiao J, Zhang L. Numerical simulation model of a free piston engine through Simulink and GT-Power. Internal Combustion Engine and Power System (Chinese Version), 2017, 34(1): 17–23 (in Chinese)

Acknowledgments

This work was supported by the project of Shanghai Science and Technology Commission (No. 19511108500).

RIGHTS & PERMISSIONS

2022 Higher Education Press 2022