FREE PISTON LINEAR ENGINE

A REVIEW ON FREE PISTON LINEAR ENGINE AND ITS CONTROL SYSTEMBY: SHAFEEQUR RAHMAN S.ISURYA KANDHASWAMY TDr P. GOPALDepartment of Automobile EngineeringANNA UNIVERSITYBHARADHIDASAN INSTITUTE OF TECHNOLOGY(BIT) CAMPUSTIRUCHIRAPPALLI-620024

CONTENTSIntroductionFree-piston engine basics Operating principlePiston configuration Single piston Dual piston Opposed pistonExperimental setupsPiston dynamics and control Starting Misfiring Applications of FPLEConclusionReferences

IntroductionFPLE is nothing but an engine works without crankshaftInstead of crankshaft , here an turbine and linear alternator is used to convert the rotary motion into reciprocatory motionThis crank less engine reduce the losses due the crankshaft

Operating principle

PISTON CONFIGURATIONSingle piston.Dual piston. Opposed piston.

Experimental systems

Single piston engine with linear alternatorOpposed piston engine setupDual piston engine setup

PISTON DYNAMICS AND CONTROL

Timing ControlStarting/ Restarting Control Misfire ControlPiston TDC Control

Applications of FPLE

FPLEs decrease heat transfer loss in the cylinder by increasing piston acceleration, compared with conventional engines

The implementation of springs in FPLEs shows benets for increasing piston velocity and engine performance.

In addition to benet of piston dynamics, published results show that the thermal efciency of FPLEs is higher than that of conventional engines.

Applications of FPLE (cont)the simulation results of FPLEs show benets for reducing temperature-dependent emissions (NO) because the in cylinder gas temperature of FPLEs is generally lower than that of conventional engines. The variable compression ratio in FPLEs is a great benet for combustion.By changing the compression ratio, FPLEs can optimize the combustion process and operate with various kinds of fuels and HCCI combustion.A free-piston engine can not only be operated as a conventional internal combustion engine. It can also be integrated with a linear alternator to generate electric powerThe electric power can be optimized by adjusting parameters such as piston assembly mass, ignition timing, equivalence ratio, electrical resistance, and air gap.

ConclusionIn this paper, we have reviewed on FPLEs with varied designs and operating features.For piston stroke type, two-stroke FPLEs are most-commonly investigated and developed because of their advantages in structure and control.Much research has shown that a linear alternator with a high efciencypower source is an excellent power-unit candidate for HEVs. With the potential offered by high-efciency linear alternators in FPLEs, we expect integrated systems to be further developed and applied in the near future.

References

Mikalsen R, Roskilly AP. A review of free-piston engine history and application. Appl Therm Eng 2007; 27:233952. Mikalsen R, Roskilly AP. The control of a free-piston engine generator. Part 1: fundamental analysis. Appl Energy 2010; 87:127380.Goertz M, Peng L. Free piston engine its application and optimization. SAE paper 2000-01-0996; 2000.Kosaka H, Akita T, Moriya K, Goto S, Hotta Y, Umeno T, et al. Development of free piston engine linear generator system part 1 investigation of fundamental characteristics. SAE paper 2014-01-1203; 2014.Blarigan PV. Free-piston engine. US patent no. 6199519 B1; March 13, 2001.Mikalsen R, Roskilly AP. The fuel efciency and exhaust gas emissions of a low heat rejection free-piston diesel engine. Proc IMech Part A: J Power Energy 2009; 223:37984.Blarigan PV. Advanced internal combustion electrical generator. In: Proceedings of the 2001 DOE hydrogen program review. p. 116. Wakabayashi R, Takiguchi M, Shimada T, Mizuno Y, Yamauchi T. The effects of crank ratio and crankshaft offset on piston friction losses. SAE paper 2003-010983;2003.Farmer HO. Free piston compressor engines. Proc Inst Mech Eng 1947; 156:25371.Ostenberg P. Electric generator. US patent 2362151 A; 1944.

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