Theoretical Evaluation of the Maximum Work of Free-Piston Engine Generators

2017 ◽  
Vol 42 (1) ◽  
Author(s):  
Shinji Kojima
Keyword(s):  
Pressure Ratio ◽  
Adjoint Equations ◽  
Brayton Cycle ◽  
Piston Engine ◽  
Theoretical Evaluation ◽  
Free Piston ◽  
Free Piston Engine ◽  
Parametric Studies ◽  
Maximum Work ◽  
Work Done

AbstractUtilizing the adjoint equations that originate from the calculus of variations, we have calculated the maximum thermal efficiency that is theoretically attainable by free-piston engine generators considering the work loss due to friction and Joule heat. Based on the adjoint equations with seven dimensionless parameters, the trajectory of the piston, the histories of the electric current, the work done, and the two kinds of losses have been derived in analytic forms. Using these we have conducted parametric studies for the optimized Otto and Brayton cycles. The smallness of the pressure ratio of the Brayton cycle makes the net work done

Maximum Work of Free-Piston Stirling Engine Generators

2017 ◽  
Vol 42 (2) ◽  
Author(s):  
Shinji Kojima
Keyword(s):  
Stirling Engine ◽  
Joule Heat ◽  
Adjoint Equations ◽  
Carnot Cycle ◽  
Work Loss ◽  
Free Piston ◽  
Maximum Work ◽  
Free Piston Stirling Engine ◽  
Work Done

AbstractUsing the method of adjoint equations described in Ref. [1], we have calculated the maximum thermal efficiencies that are theoretically attainable by free-piston Stirling and Carnot engine generators by considering the work loss due to friction and Joule heat. The net work done by the Carnot cycle is

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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