Experimental investigation of operating characteristics and thermal balance of a miniature free-piston linear engine

2020 ◽  
Vol 178 ◽  
pp. 115608
Author(s):  
Fujun Huang ◽  
Wenjun Kong
Keyword(s):  
Experimental Investigation ◽  
Thermal Balance ◽  
Operating Characteristics ◽  
Free Piston ◽  
Linear Engine

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.

The High Performance Toroidal Engine Concept (HiPerTEC)

2011 ◽  
Author(s):  
Karl V. Hoose ◽  
Eric E. Shorey
Keyword(s):  
High Performance ◽  
Combustion Process ◽  
Thermodynamic Cycle ◽  
Unmanned Vehicles ◽  
Advanced Materials ◽  
Specific Power ◽  
Operating Characteristics ◽  
Free Piston ◽  
Engine Design ◽  
Swept Volume

The traditional reciprocating I.C. engine has evolved to a point where significant improvements in thermal efficiency and specific power are not expected. Modifications to existing engines may prove to be difficult and expensive while resulting in only marginal gains. In addition, most modifications result in added components that often increase cost and decrease reliability of the system as a whole. For applications requiring major advances in performance, such as unmanned vehicles, meeting mission requirements will likely stem from a revolutionary rather than an evolutionary engine design. The slider crank mechanism is a major impediment to the traditional reciprocating I.C. engine. Although this mechanism has been used for the past 100 years, it is very wasteful of the available energy supplied by the combustion process, where piston-liner interactions from this arrangement accounts for 50–70% of the total friction losses in this engine design. Eliminating the slider crank could significantly reduce friction losses and provide additional benefits that can increase fuel conversion efficiency. The HiPerTEC engine is an opposed, free-piston engine arranged in a toroidal configuration with two counter reciprocating sets of pistons. The counter reciprocating masses eliminate the vibration found in linear free-piston engines. The HiPerTEC employs a unique shared volume configuration where the swept volume is twice the physical cylinder volume. This attribute offers a significant increase in specific power, while the free-piston characteristics provide for substantial gains in thermodynamic cycle efficiency. An eight cylinder/chamber arrangement offers balanced operation in both two and four-stroke cycle modes to allow for a wide operating envelope. The final HiPerTEC configuration will require advanced materials to address lubrication and cooling requirements. This paper discusses the HiPerTEC design, operating characteristics, development progress to date, and the challenges that lie ahead.

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 A new concept of upflow clarification in activated sludge separation

1986 ◽  
Vol 13 (5) ◽  
pp. 517-522
Author(s):  
Arthur B. Sparling ◽  
David L. Woytowich
Keyword(s):  
Experimental Study ◽  
Experimental Investigation ◽  
Activated Sludge ◽  
Key Words ◽  
Laboratory Study ◽  
Removal Mechanism ◽  
Operating Characteristics ◽  
Activated Sludge System ◽  
Gravity Sedimentation ◽  
Settling Characteristics

An experimental investigation was conducted to evaluate a new concept of upflow clarification. A novel sludge removal mechanism that used the entire floor area for the removal of solids was incorporated in an upflow clarifier. The operating characteristics and design features of the continuous flux upflow clarifier (CFLUC) are described in detail. The laboratory study was conducted to determine the effectiveness of the CFLUC clarifier in separating sludges with different settling characteristics. The different sludge types were produced by an activated sludge system treating a synthetic dairy waste at four different food to microorganism (F: M) ratios. At low organic loadings (0.10–0.24 (g COD)(g MLVSS)−1 (d)−1), the CFLUC clarifier removed 70% of the pinpoint floe that remained during quiescent batch settling conditions. At high organic loadings (0.41–0.83 (g COD)(g MLVSS) −1 (d) −1), the CFLUC clarifier was capable of separating filamentous bulking sludges with poor settling characteristics. Based on the results of the experimental study the upflow clarifier effectively separated all sludge types over the range of organic loadings investigated. Key words: CFLUC clarifier, secondary clarification, upflow clarification, sludge blanket, bioflocculation, bulking sludge, gravity sedimentation.

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