Testing and Modeling of a Miniature Air Compressor for a Prototype Free-Piston Engine

2015 ◽  
Author(s):  
Dustin L. Johnson ◽  
David B. Kittelson ◽  
William K. Durfee
Keyword(s):  
Power Supply ◽  
Ideal Gas ◽  
Piston Engine ◽  
Free Piston ◽  
Load Pressure ◽  
Conservation Of Energy ◽  
Air Compressor ◽  
Free Piston Engine ◽  
Speed Range ◽  
Bench Testing

A miniature free-piston engine air compressor is under development as a portable compact power supply. The performance of the air compressor side of the device was measured by separating the compressor portion from the free-piston engine and bench testing it independently. The compressor was operated over a speed range of 1000 to 10,000 cycles per minute, and output mass flow of air was measured with a load pressure range of 0 to 415 kPa (0 to 60 psi) above ambient. Two thermodynamic models of the air compressor were created. The first divided the compressor cycle into four ideal gas processes. The second model simulated the cycle through many small steps, calculating the thermodynamic states iteratively using conservation of energy for an open system. Valve effects and leakage losses were included in both models. The models were validated by comparing the results with experimental data.

Simulation of an Opposed-Piston Four-Stroke Free-Piston Generator

2013 ◽  
Vol 336-338 ◽  
pp. 585-589 ◽  
Author(s):  
Zhao Ping Xu ◽  
Si Qin Chang
Keyword(s):  
Combustion Process ◽  
Electrical Energy ◽  
State Equation ◽  
Ideal Gas ◽  
Piston Engine ◽  
Piston Motion ◽  
Free Piston ◽  
Free Piston Engine ◽  
Dynamical Properties ◽  
The Ideal

In order to achieve efficient conversion of the chemical energy of fuel into the electrical energy, a novel opposed-piston four-stroke free-piston generator is developed in this paper by equipping one free-piston engine with two linear generators. Mathematical models of the opposed-piston four-stroke free-piston generator are created based on the kinetic equation of the free-piston motion, the state equation of the ideal gas, and an equivalent heat release function of the combustion process. Dynamical properties of the system are simulated and analyzed by using the created model, and results from the simulation are presented. According to the simulation, the new four-stroke free-piston generator can realize running without vibrations.

Free Piston Engine Based Mobile Fluid Power Source

2016 ◽  
Author(s):  
Keyan Liu ◽  
Chen Zhang ◽  
Zongxuan Sun
Keyword(s):  
Combustion Engine ◽  
Power Source ◽  
Fluid Power ◽  
Piston Engine ◽  
Free Piston ◽  
Load Pressure ◽  
Control Effectiveness ◽  
Free Piston Engine ◽  
Output Flow ◽  
Working Principle

As a novel alternative of internal combustion engine (ICE), the free piston engine (FPE) eliminates the mechanical crankshaft and the associated constraints on its piston motion. Due to this extra degree of freedom and reduced inertia, the FPE is able to generate variable output power with higher efficiency and less emissions, while possessing a short response time. Hence, a hydraulic FPE (HFPE), which combines the FPE with a linear hydraulic pump, is a promising candidate as a fluid power source, especially for mobile applications. In this paper, such potential is investigated. The working principle of a prototype HFPE as a fluid power source is described and a comprehensive HFPE model is developed. Two novel control methods are proposed to regulate the output flow rate at any given load pressure so as to realize throttle-less fluid power control. Effectiveness of these two methods are demonstrated through simulation, where results clearly show the effectiveness of both methods in providing different output flow rates at given load pressure, thus demonstrating the HFPE’s capability as an efficient and flexible mobile fluid power source.

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.

A review on the operating characteristics of free piston engine and its recent developments

2018 ◽  
Author(s):  
Evelyn Evelyn ◽  
A. Rashid A. Aziz ◽  
Firmansyah Firmansyah ◽  
Ezrann Zharif Zainal Abidin
Keyword(s):  
Operating Characteristics ◽  
Piston Engine ◽  
Free Piston ◽  
Free Piston Engine ◽  
Recent Developments

scholarly journals Research of a Hybrid Diesel Locomotive Power Plant Based on a Free-Piston Engine

2020 ◽  
Vol 22 (3) ◽  
pp. 103-109
Author(s):  
Serhiy Buriakovskyi ◽  
Borys Liubarskyi ◽  
Artem Maslii ◽  
Danylo Pomazan ◽  
Tatyana Tavrina
Keyword(s):  
Internal Combustion Engine ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Diesel Generator ◽  
Piston Engine ◽  
Diesel Locomotive ◽  
Free Piston ◽  
Electric Transmission ◽  
Free Piston Engine ◽  
Hybrid Transmission

This article describes one of the possible ways for improving the energy efficiency of shunting diesel locomotives. It means a replacing a traditional traction electric transmission with a diesel generator set with a hybrid transmission with a free-piston internal combustion engine and a linear generator. The absence of a crankshaft in an internal combustion engine makes it possible to reduce thermal and mechanical losses, which, in turn, leads to an increase in the efficiency of traction electric transmission of the diesel locomotive.

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