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

Feng, Huihua; Guo, Yuyao; Song, Yunbo; Guo, Chendong; Zuo, Zhengxing

doi:10.3390/en9060453

Cited by 12 publications

(9 citation statements)

References 24 publications

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“…When the FPLG has two cylinders, the piston motion is mainly controlled by LEM during the starting process. Some studies focused on the starting process using position feedback or the constant-magnitude motoring force approach [37,[42][43][44][45]. In order to obtain a desired piston trajectory, the position error serves as a feedback variable to control the thrust force with appropriate value and direction [43].…”

Section: Atarting Methods Of Fplgsmentioning

confidence: 99%

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A Review of the Design and Control of Free-Piston Linear Generator

et al. 2018

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The Free-piston linear generator (FPLG) is a novel energy converter which can generate electrical energy and is regarded as a potential technology for solving the restriction of the short driving range of electric vehicles. Getting rid of the crank and flywheel mechanism, FPLG obtains some advantages of a variable compression ratio, compact size, and highly-efficient power generation. Linear electric machine (LEM) design and piston motion control are two key technologies of FPLG. However, they are currently the main obstacles to the favorable performance of FPLG. LEM being used to drive the piston motion or generate electric energy is an integrated design including a motor/generator. Various types of LEMs are investigated, and suitable application scenarios based on advantages and disadvantages are discussed. The FPLG's controller is used to ensure stable operation and highly-efficient output. However, cycle-to-cycle variations of the combustion process and motor/generator switching make it difficult to improve the performance of the piston motion control. Comments on the advantages and disadvantages of different piston motion control methods are also given in this paper.The piston moves freely between TDC and bottom dead center (BDC), and its motion is determined by the resultant force that is acting upon it, including gas pressure force, electro-magnetic force, and rebound force [8][9][10]. The piston motion must be controlled by an electronic control system-an electronic crankshaft, which is an integrated control of combustion parameters or control variables of the LEM and rebound devices [5]. Moreover, there are cycle-to-cycle variations and periodic large disturbances during the combustion process. As a result, piston motion control is still the biggest challenge of FPLG [11]. Besides, LEM is not only used as a power output unit but also a control unit for adjusting the movement of the piston. For the FPLG, LEM requires high reliability, high precision, high efficiency, and so on. Various structures of LEM designed by many teams around the world have been investigated, but none of these meet all of the requirements due to the short stroke, high frequency, and high acceleration.In order to lucubrate the current existing problems, this paper reviews the key technologies of LEM design and FPLG motion control. Firstly, several basic structures of FPLG are introduced, and both their advantages and disadvantages are analyzed. Afterwards, according to the different types of structure, corresponding advantages and disadvantages of LEMs are presented. With respect to the existing LEMs, they are classified according to the different flux path and topology structures in the third section. Finally, different starting methods are introduced based on the FPLG's structure. In terms of power generation stage, piston motion control strategies are divided into three forms and introduced based on their control variables. They include three categories: active combustion parameters control, active LEM control, and the mixed cont...

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Section: Atarting Methods Of Fplgsmentioning

confidence: 99%

“…Free-piston engine estimation and control system at Newcastle University[44].Energies 2018, 11, x FOR PEER REVIEW 14 of 21 Energies 2018, 11, x; doi: FOR PEER REVIEW www.mdpi.com/journal/energies…”

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confidence: 99%

A Review of the Design and Control of Free-Piston Linear Generator

et al. 2018

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“…The FPE is a unique thermal hybrid propulsion machine with a higher thermal efficiency than its counterpart, the Conventional Reciprocating Piston Engine (CPE). Moreover, the system dynamics intrinsically influence the piston motion, advantages of which can lead to the optimisation of several operational modes [4,5].…”

Section: Symbolsmentioning

confidence: 99%

Non-Linear and Multi-Domain Modelling of an Opposed-Piston Free Piston Engine during Motoring

Patrick¹,

Brosnan²,

Tian³

et al. 2022

Preprint

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When coupling the Free Piston Engine (FPE) to the Permanent Magnet Linear Synchronous Machine (PMLSM) to produce electrical energy, its intrinsic multidirectional and non-linear dynamics have been typically described in a simplified mono-directional and linear fashion when considering a system-level modelling approach.This paper presents a detailed, multi-directional, multi-domain model of the FPE and PMLSM. The model was implemented in an opposed-piston free-piston engine configuration and validated against experimental data captured from a prototype with identical parameters. The simulation results indicate a strong correlation to the experimental data, which captured the dominant dynamics of the FPE and proved the satisfactory accuracy and performance of the model.This study considers the characteristic multidirectional nature and non-linearity of the machine dynamics and its interactions with multi-physical domains such as electrical, mechanical, and pneumatic.

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“…Piston displacement E x p a n s io n C o m p r e s s i o n Advances in Materials Science and Engineering that can increase the e ciency of MCLG system. e structure has the advantages of less moving mass, fast response, and low coil inductance [18,19].…”

Section: Pressurementioning

confidence: 99%

Two-Stroke Thermodynamic Cycle Optimization of a Single-Cylinder Free-Piston Engine Generator

Zhang

et al. 2019

Advances in Materials Science and Engineering

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A free-piston engine generator (FPEG) is a new type of energy converter, which eliminates the crankshaft and connecting rod mechanism. In order to achieve efficient energy conversion, the two-stroke thermodynamic performance optimization of a single-cylinder free-piston engine generator is investigated in this paper. Firstly, the components, four-stroke thermodynamic cycle, two-stroke thermodynamic cycle, and prototype system of the FPEG are presented in detail. The one-dimensional flow simulation model of the FPEG is created based on the gas dynamics equation, Weber combustion function, and heat transfer function, and then the model is validated by the data tested from the prototype system. According to the four-stroke experimental results of the FPEG, an effective power of 4.75 kW and a peak pressure of 21.02 bar have been obtained. Then, the two-stroke thermodynamic cycle is simulated and compared under the different control parameters of intake air pressure, injection timing, ignition timing, and valve timing through the simulation model. The optimized results show that an indicated thermal efficiency of 27.6%, an indicated power of 6.7 kW, and a maximal working frequency of 25 Hz can be achieved by the prototype system, when the two-stroke thermodynamic cycle is used.

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

Cited by 12 publications

References 24 publications

A Review of the Design and Control of Free-Piston Linear Generator

A Review of the Design and Control of Free-Piston Linear Generator

Non-Linear and Multi-Domain Modelling of an Opposed-Piston Free Piston Engine during Motoring

Two-Stroke Thermodynamic Cycle Optimization of a Single-Cylinder Free-Piston Engine Generator

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