scholarly journals METHODS OF STRUCTURAL AND PARAMETRIC SYNTHESIS OF COMBINED GENERATOR OF RECIPROCATING POWER PLANTS FOR ROBOTIC SYSTEMS ON THE BASIS OF A FREE PISTON ENGINE

2018 ◽  
Vol 63 (2) ◽  
pp. 229-243
Author(s):  
A. B. Menzhinsky ◽  
A. N. Malashin
Keyword(s):  
Power Plant ◽  
Specific Gravity ◽  
Power Plants ◽  
Robotic Systems ◽  
Piston Engine ◽  
Free Piston ◽  
Parametric Synthesis ◽  
Free Piston Engine ◽  
Electromechanical Energy ◽  
Combined Generator

Power supply system of advanced robotic systems requires the development of electromechanical energy converters with high energy and minimum weight and overall dimensions. In this regard, a free piston engine with an electric generator is considered as a promising plant.Interest in the study of power plants based on free piston engines is caused by several advantages compared to conventional internal combustion engines with a crank mechanism: relative simplicity of the design, 40 % fewer elements, which reduces the overall capacity, specific gravity and metal content of the free piston engine in 2.5–3 times. In addition, the fuel consumption is 30 % lower. Also an important design advantage of power plants based on free piston engines is a relatively simple modular construction. Reciprocating electric generators with transverse increment of the magnetic flux are the most commonly used ones in currently developed power plants based on free piston engines of foreign countries (USA, Russia, Germany, China, UK, Japan, Sweden, Israel, etc.) as the electrical AC machines. The main disadvantage of this type of generators are the absence of coordination of electrical and mechanical subsystems of the power plant at the extreme points of the operating cycle, which limits the efficiency of the free piston engine and reduces the reliability of the power plant.To solve this problem it is proposed to use Electromechanical energy Converter with transverse and longitudinal increment of the magnetic flux (combo generator). However, currently there is no scientifically valid method of synthesis of this type of generator. To address this problem we have developed the methodology of structural and parametric synthesis of combined generator of the reciprocating type for a plant on the basis of free piston engine, which is based on the use of the specific gravity of the combined generator as the objective function. It allows synthesizing electric machine of the reciprocating type with the specified efficiency and minimum specific mass. 

scholarly journals Coordination of forces of mechanical and electric subsystems of power plant with free piston engine and electric generator of reciprocating type

2019 ◽  
Vol 64 (3) ◽  
pp. 304-320 ◽  
Author(s):  
A. B. Menzhinski
Keyword(s):  
Power Plant ◽  
Specific Gravity ◽  
High Energy ◽  
Piston Engine ◽  
Free Piston ◽  
Operating Cycle ◽  
Electric Generator ◽  
Free Piston Engine ◽  
Work Cycle ◽  
Electromechanical Energy

Autonomous power supply system of modern mobile special-purpose equipment requires the development of electromechanical energy converters with high energy and minimum weight- and size indicators. In industrialized countries, the system “free piston engine – reciprocating electric generator of transverse type” is considered as a promising power plant. The main feature of this kind of power plant is the lack of crank mechanism in the engine design. This allows: increasing the efficiency of the engine up to 50–60 % and overall power by 2.5–3 times while reducing the specific gravity and metal consumption compared to traditional engines; reducing the specific fuel consumption of the engine up to 30 %; increasing the resource to overhaul by 30–50 thousand hours; implementing a modular structure. The main drawbacks of this kind of power plant are high probability of failure when passing the ignition of the working mixture and instability of work with significant load fluctuations. The noted drawbacks are due to the inconsistency of the forces of the electrical and mechanical subsystems of the power plant throughout the operating cycle. The solution for the problem of matching the forces of the electrical and mechanical subsystems of the power plant in the extreme positions of the piston group of the free piston engine is of particular complexity. In this regard, a method for solving the problem of matching the forces of the mechanical and electrical subsystems of the power plant with a free-piston engine throughout the operating cycle was developed, characterized by the use of an electromechanical reciprocating energy converter with transverse- and longitudinal nonlinear changes in the magnetic flux in the electrical subsystem. Coordination of the forces of mechanical and electrical subsystems of the power plant on the entire operating cycle makes it possible to fulfill the conditions of continuous electromechanical energy conversion at all work cycle and to reduce the specific gravity of the electrical subsystems of the plant while improving efficiency.

New Free-Piston Topping Cycle for Gas-Turbine Power Plants

2003 ◽  
Author(s):  
William L. Kopko ◽  
John S. Hoffman
Keyword(s):  
High Performance ◽  
Power Plants ◽  
Waste Heat ◽  
Combustion Engine ◽  
Complete Recovery ◽  
Combined Cycle ◽  
Piston Engine ◽  
Free Piston ◽  
Free Piston Engine ◽  
Topping Cycle

A proposed topping cycle inserts a free-piston internal-combustion engine between the compressor and the combustor of a combustion turbine. The topping cycle diverts air from the compressor to supercharge the free-piston engine. Because the free-piston engine uses gas bearings to support the piston and is built of high-temperature materials, the engine can increase the pressure and temperature of the gas, exhausting it to a small expander that produces power. The exhaust from the topping-cycle expander is at a pressure that can be re-introduced to the main turbine, allowing almost complete recovery of waste heat. A capacity increase exceeding 35% is possible, and overall cycle efficiency can approach 70% when incorporated into a state-of-the-art combined-cycle plant. The cost of per incremental kW of the topping cycle can be dramatically lower than that of the base turbine because of the high power density and simplicity of the engine. Building on decades of progress in combustion turbines systems, the new cycle promises high performance without the engineering risks of manufacturing a completely new cycle.

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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