Influence of Pressure Build-Up Time of Compression Chamber on Improving the Operation Frequency of a Single-Piston Hydraulic Free-Piston Engine

Xie, Haibo; Ren, Haoling; Yang, Huayong; Jianfei, Guo

doi:10.1155/2013/406807

Cited by 3 publications

(2 citation statements)

References 12 publications

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“…There are two strokes in one working cycle; each cylinder finishes a compressor stroke, expands the stroke, exhausts the stroke and inputs a stroke after two working cycles. This engine has low emissions and low fuel consumption [60]. lished mathematical models and prototype test platforms at the same time.…”

Section: Zhejiang Universitymentioning

confidence: 99%

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

Zhang

Zhao

et al. 2021

Energies

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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.

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Section: Zhejiang Universitymentioning

confidence: 99%

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

Zhang

Zhao

et al. 2021

Energies

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show abstract

“…Furthermore, mechanical simplicity, low frictional losses, low cost and high operational flexibility are also the most attracting merits, which have encouraged many research institutes and researchers to devote themselves to developing it since 1980s. [1][2][3][4][5][6] But till now, only the single-piston hydraulic free piston engine (SHFPE) has been tested in hydraulic forklifts. 2,7 There are some key technologies which restricted the development of HFPE, such as vibration, synchronization of the fuel injection, scavenge ratio and compression ratio control.…”

Section: Introductionmentioning

confidence: 99%

Stability research of the compression process of two-cylinder four-stroke single-piston hydraulic free piston engine

Ren

Lin

Xie

et al. 2016

Proceedings of the Institution of Mechanical Engineers, Part C:

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An invariable compression ratio in certain conditions must be achieved to ensure a steady and efficient performance of the single-piston hydraulic free piston engine. The compression ratio is determined by the characteristics of the compression stroke. The mathematical models of the key components during the compression process are established. The kinematic characteristics of the free piston assembly are analyzed under two conditions. One condition is that free piston assembly is driven by the compression accumulator only and the other one is that free piston assembly is driven by the compression accumulator and the pump station. Pressures in compression accumulator and compression chamber are analyzed and compared in both conditions. According to the experimental results, pressures in the compression chamber and compression accumulator are not constant in both conditions during the compression process. The compression stroke and compression time vary with the changing of the pressure in the compression accumulator, which adds the complexity and changeability to the compression ratio control. An improved configuration is put forward to solve the pressure variation. The results show that the improved configuration can make the pressure invariable at the inlet of the compression chamber and the compression process keeps almost the same regardless of the pressure changing in the compression accumulator. With this new structure, there is about 2.5% energy loss, which is acceptable considering the stable compression stroke.

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Experimental study of hydraulic electronic unit injector in a hydraulic free piston engine

Zhang

Zhao

et al. 2016

Applied Energy

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Influence of Pressure Build-Up Time of Compression Chamber on Improving the Operation Frequency of a Single-Piston Hydraulic Free-Piston Engine

Cited by 3 publications

References 12 publications

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

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

Stability research of the compression process of two-cylinder four-stroke single-piston hydraulic free piston engine

Experimental study of hydraulic electronic unit injector in a hydraulic free piston engine

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