scholarly journals Free-Piston Engine Design and Evaluation with Different Compression Ratios

2021 ◽  
Vol 13 (3) ◽  
pp. 57-66
Author(s):  
B. KIRUBADURAI ◽  
G. JEGADEESWARI ◽  
K. KANAGARAJA
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Power Generation ◽  
Operating Performance ◽  
Research Groups ◽  
Piston Engine ◽  
Free Piston ◽  
Heat Engines ◽  
Free Piston Engine ◽  
Engine Design

Free-piston heat engines are being examined by a number of international research groups as an option for conservative technology, as they are not limited by the movement of the crankshaft as in conventional engines. The free-piston engines are employed in applications like power generation using conventional methods. The higher compression ratios provide higher cycle efficiencies and also boost in-cylinder temperatures increasing mechanical stress, pressures, and heat transfer losses. This paper presents different in-cylinder flows by computational fluid dynamics for various compression ratios ranges from 7 to 15 and estimates were made to find best compression ratio for the optimal engine operating performance and characteristic.

In-cylinder heat transfer and gas motion of a free-piston diesel engine generator

2017 ◽  
Vol 231 (8) ◽  
pp. 739-752 ◽  
Author(s):  
Chenheng Yuan ◽  
Jing Xu ◽  
Huihua Feng
Keyword(s):  
Heat Transfer ◽  
Gas Flow ◽  
Attractive Alternative ◽  
Piston Engine ◽  
Piston Motion ◽  
Compression Process ◽  
Free Piston ◽  
Reciprocating Engine ◽  
Free Piston Engine ◽  
Significant Difference

The free-piston engine generator is an attractive alternative to the conventional reciprocating engine due to the feature that it moves without crankshaft system. This paper presented a simulation for the investigation on the characteristic of in-cylinder gas motion and heat transfer in a compression ignited free-piston engine generator. An operation experiment was performed to obtain the precise piston motion for the modeling of heat transfer and gas flow. The development of the multi-dimensional model was described, and simulation results were presented and showed good similarity with the experimental data. Then, the heat transfer and gas motion in the free-piston engine generator were discussed, on which the influences of piston motion were also investigated compared with a corresponding conventional reciprocating engine. The results indicated that compared with the conventional reciprocating engine, a higher level of squish and reverse squish effect was found for the free-piston engine generator due to its faster motion around top dead center, while its slower piston motion led to weaker gas turbulence in the compression process. Moreover, the free-piston engine generator and conventional reciprocating engine did not show a significant difference in heat transfer during the compression process, however, an obvious advantage of heat transfer was indicated for the free-piston engine generator in combustion and expansion processes due to its lower combustion temperature and the reduced time that is available for heat transfer caused by its faster expansion. The mechanism for such differences is that the free-piston engine generator moves with uneven equivalent speed.

Simulation of Coolant Flow and Heat Transfer for Hydraulic Free Piston Engine Water Jacket

2013 ◽  
Vol 694-697 ◽  
pp. 570-576
Author(s):  
Peng Li ◽  
Zhao Cheng Yuan ◽  
Chao Guo ◽  
Ying Xiao Yu
Keyword(s):  
Heat Transfer ◽  
Cooling System ◽  
Three Dimensional ◽  
Coolant Flow ◽  
Piston Engine ◽  
Free Piston ◽  
Water Jacket ◽  
Flow And Heat Transfer ◽  
Free Piston Engine ◽  
In The Beginning

The development of hydraulic free piston engine (HFPE) in China is still in the beginning stage of exploration. Based on the project of research group, the coolant flow and heat transfer of water jacket’s for the HFPE were simulated with the three-dimensional CFD software FLUENT, and the field information of the velocity field, pressure field and the transfer coefficient of coolant in the water jacket were achieved. The results indicate that the requirement of cooling system can be meet except some small problems, but it provides a reference for the engine design in the future.

Effect of Piston Motion on Combustion of CNG Free Piston Engine (FPE)

2014 ◽  
Vol 889-890 ◽  
pp. 501-506
Author(s):  
Ning Xia Yin ◽  
Zhao Ping Xu ◽  
Si Qin Chang ◽  
Ji Ming Lin
Keyword(s):  
Heat Transfer ◽  
Combustion Process ◽  
Engine Performance ◽  
Expansion Ratio ◽  
Nox Emissions ◽  
Piston Engine ◽  
Piston Motion ◽  
Free Piston ◽  
Beneficial Effects ◽  
Free Piston Engine

CNG is thought to be one of the most promising alternatives to traditional fuels. The multi-fuel ability is another characteristic of the FPE. The piston motion can be controlled to have beneficial effects on the engine performance. This article investigates the effect of piston motion on combustion of four-stroke CNG FPE using a multidimensional simulation model. It is found that the high piston acceleration and velocity at top dead center increases expansion ratio and fasting combustion, reduces the heat transfer losses and decreased NOx emissions formation. At the same time, the turbulent kinetic energy of the gas during the combustion process is added.

An Investigation on Power Generation Characteristics of Linear Generator Driven by a Free-piston Engine

2021 ◽  
Author(s):  
Nguyen Huynh Thi ◽  
Nguyen Van Trang ◽  
Huynh Thanh Cong ◽  
Dao Huu Huy ◽  
Huynh Van Loc ◽  
...  
Keyword(s):  
Power Generation ◽  
Piston Engine ◽  
Free Piston ◽  
Linear Generator ◽  
Free Piston Engine

scholarly journals Wall Heat Transfer Analysis of Internal Combustion Engine with Free Piston Linear Motion

2018 ◽  
Vol 7 (3.17) ◽  
pp. 141
Author(s):  
Mior A. Said ◽  
L K. Mun ◽  
A R. A. Aziz ◽  
. .
Keyword(s):  
Heat Transfer ◽  
Transfer Rate ◽  
Combustion Engine ◽  
Linear Motion ◽  
Piston Engine ◽  
Piston Motion ◽  
Free Piston ◽  
Free Piston Engine ◽  
Set Up ◽  
Motion Profile

The manuscript should contain an abstract. The abstract should be self-contained and citation-free and should not exceed 200 words. The abstract should state the purpose, approach, results and conclusions of the work.  The author should assume that the reader has some knowledge of the subject but has not read the paper. Thus, the abstract should be intelligible and complete in it-self (no numerical references); it should not cite figures, tables, or sections of the paper. The abstract should be written using third person instead of first person. Intensive researches are being carried out on the main power generator for free piston linear generator(FPLG) by both the academic and industrial research group due to its potential as a high fuel efficiency and low emission engine. The linear generator, which is a coil and a translator positioned to move linearly back and forth relative to each other. The study investigates the heat transfer data of internal combustion engine with free piston linear motion profile and compared with the conventional reciprocating engine for one cycle motion only. Engine simulation software GT-Power is employed which utilize the 1-D thermodynamic modeling. All parameters for both free-piston engine are set-up to be the same except for the piston motion profile and the injection timing. Both conventional and free piston engine models are built, simulation settings are set up, and simulations are launched in GT-ISE.  Once simulation is done, results are viewed in GT-POST, the data collected was analysed and compared to investigate the dictinct effect of piston motion to heat transfer profile and data. The overall trend shows that free piston engine have a lower heat transfer rate throughout majority of the cycle. This finding agrees that due to less time of piston near top dead centre area, heat transfer losses to the wall per cycle are reduced. The heat transfer profile of the free piston also shown distinct feature compared to conventional with rapid increase and decrease of heat transfer rate, followed by a secondary peak of gradual decline of the profile.  

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.

Sign in / Sign up

Export Citation Format

Share Document