scholarly journals Electromagnetic Loss Analysis of a Linear Motor System Designed for a Free-Piston Engine Generator

Electronics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 621 ◽  
Author(s):  
Yunqin Hu ◽  
Zhaoping Xu ◽  
Lijie Yang ◽  
Liang Liu
Keyword(s):  
Motor System ◽  
Pulse Width Modulation ◽  
High Efficiency ◽  
Electrical Energy ◽  
Element Model ◽  
Energy Conversion Efficiency ◽  
Linear Motor ◽  
Piston Engine ◽  
Free Piston ◽  
Free Piston Engine

A free-piston engine generator is a new type of power generating device, which has the advantages of high efficiency and simple structure. In this paper, a linear motor system composed of a moving-coil linear motor with axial magnetized magnets and a H-bridge pulse-width modulation (PWM) rectifier is designed for portable free-piston engine generators. Based on the finite-element model of the motor and physical model of the rectifier, the combined electromagnetic model is presented and then validated by the prototype-tested results. The electromagnetic processes of the linear motor system are simulated. The electromagnetic losses during the standard working cycle are analyzed. Under the rated reciprocating frequency of 50 Hz and the rated reciprocating stroke of 36 mm, the mechanical-to-electrical energy conversion efficiency of 86.3% can be obtained by the linear motor system, which meets the requirement of portable free-piston engine generators.

scholarly journals Research on the Operating Characteristics of Hydraulic Free-Piston Engines: A Systematic Review and Meta-Analysis

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3530
Author(s):  
Fukang Ma ◽  
Shuanlu Zhang ◽  
Zhenfeng Zhao ◽  
Yifang Wang
Keyword(s):  
Systematic Review ◽  
High Efficiency ◽  
Meta Analysis ◽  
Combustion Process ◽  
Research Progress ◽  
Future Research ◽  
Operating Characteristics ◽  
Piston Engine ◽  
Free Piston ◽  
Free Piston Engine

The hydraulic free-piston engine (HFPE) is a kind of hybrid-powered machine which combines the reciprocating piston-type internal combustion engine and the plunger pump as a whole. In recent years, the HFPE has been investigated by a number of research groups worldwide due to its potential advantages of high efficiency, energy savings, reduced emissions and multi-fuel operation. Therefore, our study aimed to assess the operating characteristics, core questions and research progress of HFPEs via a systematic review and meta-analysis. We included operational control, starting characteristics, misfire characteristics, in-cylinder working processes and operating stability. We conducted the literature search using electronic databases. The research on HFPEs has mainly concentrated on four kinds of free-piston engine, according to piston arrangement form: single piston, dual pistons, opposed pistons and four-cylinder complex configuration. HFPE research in China is mainly conducted in Zhejiang University, Tianjin University, Jilin University and the Beijing Institute of Technology. In addition, in China, research has mainly focused on the in-cylinder combustion process while a piston is free by considering in-cylinder combustion machinery and piston dynamics. Regarding future research, it is very important that we solve the instabilities brought about by chance fluctuations in the combustion process, which will involve the hydraulic system’s efficiency, the cyclical variation, the method of predicting instability and the recovery after instability.

scholarly journals Design considerations of a linear generator for a range extender application

2015 ◽  
Vol 64 (4) ◽  
pp. 581-592
Author(s):  
Un-Jae Seo ◽  
Björn Riemer ◽  
Rüdiger Appunn ◽  
Kay Hameyer
Keyword(s):  
Electric Vehicle ◽  
High Efficiency ◽  
Piston Engine ◽  
Free Piston ◽  
Full Load ◽  
Linear Generator ◽  
Design Considerations ◽  
Range Extender ◽  
Free Piston Engine ◽  
Linear Generators

Abstract The free piston linear generator is a new range extender concept for the application in a full electric vehicle. The free piston engine driven linear generators can achieve high efficiency at part and full load which is suitable for the range extender application. This paper presents requirements for designing a linear generator deduced from a basic analysis of a free piston linear generator.

Thermodynamic Simulation and Prototype Testing of a Four-Stroke Free-Piston Engine

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Jiming Lin ◽  
Zhaoping Xu ◽  
Siqin Chang ◽  
Ningxia Yin ◽  
Hao Yan
Keyword(s):  
Thermodynamic Simulation ◽  
Thermodynamic Cycle ◽  
Energy Conversion Efficiency ◽  
Piston Engine ◽  
Free Piston ◽  
Free Piston Engine ◽  
Simulation And Experiment ◽  
Intake Stroke ◽  
Engine System ◽  
Insight Into

In order to achieve higher-energy conversion efficiency, a free-piston engine with an improved four-stroke thermodynamic cycle is investigated in this paper. This cycle is optimized according to the variable strokes feature and is characterized by the short intake stroke, the complete expansion stroke, the external pressurization, and the intercooling. The development of a four-stroke free-piston engine system simulation model was described, and the effects of the cycle on the system performances were qualitatively analyzed. According to the experiment of the prototype, the generating efficiency of 33.4% can be achieved when the system is fueled with gasoline and the output power is significantly increased from 1.62 to 2.68 kW. The simulation and experiment results are analyzed in detail, giving insight into the performances of the system. Studies show that the energy-saving and environmental protection performances of the system can be significantly promoted by using the improved thermodynamic cycle.

Transient Control of a Hydraulic Free Piston Engine

2013 ◽  
Author(s):  
Ke Li ◽  
Chen Zhang ◽  
Zongxuan Sun
Keyword(s):  
High Efficiency ◽  
Combustion Engine ◽  
Tracking Error ◽  
Control Signal ◽  
Piston Engine ◽  
Piston Motion ◽  
Free Piston ◽  
Engine Operation ◽  
Free Piston Engine ◽  
Transient Period

The free piston engine (FPE) is a type of internal combustion engine (ICE) with no crankshaft, so that its piston motion is no longer constrained by mechanical linkages. The FPE has a high potential in terms of energy saving given its simple structure, high modularity and high efficiency. One of the technical barriers that prevents the wide spread of the FPE technology, is the lack of precise piston motion control. Previously, a robust repetitive controller is designed and implemented to form a virtual crankshaft that would provide a precise and stable engine operation. The experimental data of engine motoring tests with virtual crankshaft demonstrates the effectiveness of the controller. However, the presence of a transient period after a single combustion event prevents the engine from continuous firing. This paper presents a modified control scheme, which utilizes a reference and control signal shifting technique to modify the tracking error and the control signal to reduce the transient period.

scholarly journals Generator Design Considering Mover Action to Improve Energy Conversion Efficiency in a Free-Piston Engine Generator

Electronics ◽  
2021 ◽  
Vol 10 (17) ◽  
pp. 2142
Author(s):  
Mitsuhide Sato ◽  
Shoma Irie ◽  
Jianping Zheng ◽  
Tsutomu Mizuno ◽  
Fumiya Nishimura ◽  
...  
Keyword(s):  
Energy Conversion ◽  
Conversion Efficiency ◽  
Design Method ◽  
Energy Conversion Efficiency ◽  
Field Analysis ◽  
Piston Engine ◽  
Free Piston ◽  
Engine Efficiency ◽  
Free Piston Engine ◽  
Linear Generators

In a free-piston engine generator (FPEG), the power of the engine can be directly regenerated by linear generators without a crank. The mover motion of this system is interrelated with engine and power generation efficiencies due to the direct connection between the mover of the generator and the piston of the engine. The generator should be designed to improve the overall energy conversion efficiency. The dimensions and mass of the mover limit its operating stroke and drive frequency. Herein, we propose a method for designing linear generators and constructing FPEG systems, considering the mover operation to improve engine efficiency. We evaluated the effect of mover operation on the engine and generation efficiencies using thermal and electromagnetic field analysis software. The proposed design method improves the overall energy conversion efficiency compared with a generator that considers only the maximization of generation efficiency. Setting the mover operation for higher engine efficiency and designing a linear generator to realize the operation can effectively improve the energy conversion efficiency of FPEGs.

Computational Design Studies for a High-Efficiency and Low-Emissions Free Piston Engine Prototype

2004 ◽  
Author(s):  
A. P. Kleemann ◽  
J.-C. Dabadie ◽  
S. Henriot
Keyword(s):  
High Efficiency ◽  
Computational Design ◽  
Piston Engine ◽  
Free Piston ◽  
Design Studies ◽  
Free Piston Engine

scholarly journals Operation Range of Generation Braking Force to Achieve High Efficiency Considering Combustion in a Free-Piston Engine Linear Generator System

2018 ◽  
Vol 7 (4) ◽  
pp. 343-350 ◽  
Author(s):  
Mitsuhide Sato ◽  
Masami Nirei ◽  
Yuichiro Yamanaka ◽  
Hironobu Murata ◽  
Yinggang Bu ◽  
...  
Keyword(s):  
High Efficiency ◽  
Piston Engine ◽  
Generator System ◽  
Free Piston ◽  
Linear Generator ◽  
Free Piston Engine ◽  
Braking Force

scholarly journals Hydraulic Free Piston Engine Enabled by Active Motion Control

2013 ◽  
Vol 135 (06) ◽  
pp. S7-S9 ◽  
Author(s):  
Ke Li ◽  
Zongxuan Sun
Keyword(s):  
Motion Control ◽  
High Efficiency ◽  
Motion Controller ◽  
Piston Engine ◽  
Piston Motion ◽  
Free Piston ◽  
Engine Operation ◽  
Active Motion ◽  
Functional Aspects ◽  
Free Piston Engine

This article explores various functional aspects of hydraulic free piston engine (FPE) enabled by action motion control. Given the potential for high efficiency and flexibility, the FPE is well suited for mobile applications such as on-road vehicles and off-road heavy machinery. The advantage of the active motion controller lies in its ability to precisely track and shape the piston trajectory. FPE has a great potential for energy saving and emission control, but its reliable operation is limited by the complex dynamic coupling among the engine subsystems and the lack of the crankshaft. This inherent technical barrier for FPE could be overcome by active control with today’s sensing, actuation and computing technologies. A prototype hydraulic FPE is used to demonstrate the capabilities of active piston motion control. Experimental results demonstrate the feasibility and promise of the technology. Engine power control will be combined with piston motion control in the future to achieve a wider range of engine operation and higher engine efficiency.

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