Multi-dimensional scavenging analysis of a free-piston linear alternator based on numerical simulation

Mao, Jinlong; Zuo, Zhengxing; Li, Wen; Feng, Huihua

doi:10.1016/j.apenergy.2010.10.003

Cited by 100 publications

(54 citation statements)

References 9 publications

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“…Assuming that the load is resistive, the LEM model can be described by the phase equivalent circuit model shown in Figure 5 [11,18,29]. According to the phase equivalent circuit model, the induced voltage and current can be derived as: According to the phase equivalent circuit model, the induced voltage and current can be derived as:…”

Section: Lem Model Under Generating Modementioning

confidence: 99%

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Hybrid System Modeling and Full Cycle Operation Analysis of a Two-Stroke Free-Piston Linear Generator

et al. 2017

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Free-piston linear generators (FPLGs) have attractive application prospects for hybrid electric vehicles (HEVs) owing to their high-efficiency, low-emissions and multi-fuel flexibility. In order to achieve long-term stable operation, the hybrid system design and full-cycle operation strategy are essential factors that should be considered. A 25 kW FPLG consisting of an internal combustion engine (ICE), a linear electric machine (LEM) and a gas spring (GS) is designed. To improve the power density and generating efficiency, the LEM is assembled with two modular flat-type double-sided PM LEM units, which sandwich a common moving-magnet plate supported by a middle keel beam and bilateral slide guide rails to enhance the stiffness of the moving plate. For the convenience of operation processes analysis, the coupling hybrid system is modeled mathematically and a full cycle simulation model is established. Top-level systemic control strategies including the starting, stable operating, fault recovering and stopping strategies are analyzed and discussed. The analysis results validate that the system can run stably and robustly with the proposed full cycle operation strategy. The effective electric output power can reach 26.36 kW with an overall system efficiency of 36.32%.

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Section: Lem Model Under Generating Modementioning

confidence: 99%

“…Assuming that the load is resistive, the LEM model can be described by the phase equivalent circuit model shown in Figure 5 [11,18,29]. …”

Section: Lem Model Under Generating Modementioning

confidence: 99%

Hybrid System Modeling and Full Cycle Operation Analysis of a Two-Stroke Free-Piston Linear Generator

et al. 2017

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“…In other words, the engine has an ignition delay period from fuel injection to combustion that lasts approximately 1 to 4 ms. We adopt the ignition delay model established by Wolfer [22] in 1938:…”

Section: Ignition Delay Modelmentioning

confidence: 99%

“…Because the in-cylinder gas temperature has a great influence on the ignition point of diesel, the factor of heat transfer must be considered in the thermodynamic model. The heat transfer process of the left side is modelled according to Hohenberg [22]:…”

Section: Thermodynamic Modelmentioning

confidence: 99%

Study of the Injection Control Strategies of a Compression Ignition Free Piston Engine Linear Generator in a One-Stroke Starting Process

et al. 2016

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For a compression ignition (CI) free piston engine linear generator (FPLG), injection timing is one of the most important parameters that affect its performance, especially for the one-stroke starting operation mode. In this paper, two injection control strategies are proposed using piston position and velocity signals. It was found experimentally that the injection timing's influence on the compression ratio, the peak in-cylinder gas pressure and the indicated work (IW) is different from that of traditional reciprocating CI engines. The maximum IW of the ignition starting cylinder, say left cylinder (LC) and the right cylinder (RC) are 132.7 J and 138.1 J, respectively. The thermal-dynamic model for simulating the working processes of the FPLG are built and verified by experimental results. The numerical simulation results show that the running instability and imbalance between LC and RC are the obvious characters when adopting the injection strategy of the velocity feedback. These could be solved by setting different triggering velocity thresholds for the two cylinders. The IW output from the FPLG under this strategy is higher than that of adopting the position feedback strategy, and the maximum IW of the RC could reach 162.3 J. Under this strategy, the prototype is able to achieve better starting conditions and could operate continuously for dozens of cycles.

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“…The researchers also analyzed and assessed two cases of spark ignition and premixed charge compression ignition combustion [14,17]. FPELG is a crankless linear dynamic system [18]. It has unique features compared with other power system such as being highly integrated with engine and generator, high power density, small friction loss, high thermal efficiency, low vibration and radiated noise, good fuel adaptability, difficulty for steady running, etc.…”

mentioning

confidence: 99%

Stable Operation and Electricity Generating Characteristics of a Single-Cylinder Free Piston Engine Linear Generator: Simulation and Experiments

et al. 2015

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Abstract:We present a novel design of a single-cylinder free piston engine linear generator (FPELG) incorporating a linear motor as a rebound device. A systematic simulation model of this FPELG system was built containing a kinematic and dynamic model of the piston and mover, a magneto-electric model of the linear generator, a thermodynamic model of the single-cylinder engine, and a friction model between the piston ring and cylinder liner. Simulations were performed to understand the relationships between pre-set motor parameters and the running performance of the FPELG. From the simulation results, it was found that a motor rebound force with a parabolic profile had clear advantages over a force with a triangular profile, such as a higher running frequency and peak cylinder pressure, faster piston motion, etc. The rebound position and the amplitude of rebound force were also determined by simulations. The energy conversion characteristics of the generator were obtained from our FPELG test rig. The parameters of intake pressure, motor frequency, and load resistance were varied over certain ranges, and relationships among these three parameters were obtained. The electricity-generating characteristic parameters include output power and system efficiency, which can measure OPEN ACCESSEnergies 2015, 8 766 the quality of matching the controllable parameters. The output power can reach 25.9 W and the system efficiency can reach 13.7%. The results in terms of matching parameters and electricity-generating characteristics should be useful to future research in adapting these engines to various operating modes.

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Multi-dimensional scavenging analysis of a free-piston linear alternator based on numerical simulation

Cited by 100 publications

References 9 publications

Hybrid System Modeling and Full Cycle Operation Analysis of a Two-Stroke Free-Piston Linear Generator

Hybrid System Modeling and Full Cycle Operation Analysis of a Two-Stroke Free-Piston Linear Generator

Study of the Injection Control Strategies of a Compression Ignition Free Piston Engine Linear Generator in a One-Stroke Starting Process

Stable Operation and Electricity Generating Characteristics of a Single-Cylinder Free Piston Engine Linear Generator: Simulation and Experiments

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