Research on simulation and experiment of fast response frequency control valve in Hydraulic free piston engine

2011 ◽  
Author(s):  
Mingzhi Song ◽  
Yang Wang ◽  
Qian Xiong ◽  
Xudong Zhen ◽  
Shuaiqing Xu ◽  
...  
Keyword(s):  
Frequency Control ◽  
Control Valve ◽  
Fast Response ◽  
Piston Engine ◽  
Free Piston ◽  
Response Frequency ◽  
Free Piston Engine ◽  
Simulation And Experiment

Thermodynamic Simulation and Prototype Testing of a Four-Stroke Free-Piston Engine

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Jiming Lin ◽  
Zhaoping Xu ◽  
Siqin Chang ◽  
Ningxia Yin ◽  
Hao Yan
Keyword(s):  
Thermodynamic Simulation ◽  
Thermodynamic Cycle ◽  
Energy Conversion Efficiency ◽  
Piston Engine ◽  
Free Piston ◽  
Free Piston Engine ◽  
Simulation And Experiment ◽  
Intake Stroke ◽  
Engine System ◽  
Insight Into

In order to achieve higher-energy conversion efficiency, a free-piston engine with an improved four-stroke thermodynamic cycle is investigated in this paper. This cycle is optimized according to the variable strokes feature and is characterized by the short intake stroke, the complete expansion stroke, the external pressurization, and the intercooling. The development of a four-stroke free-piston engine system simulation model was described, and the effects of the cycle on the system performances were qualitatively analyzed. According to the experiment of the prototype, the generating efficiency of 33.4% can be achieved when the system is fueled with gasoline and the output power is significantly increased from 1.62 to 2.68 kW. The simulation and experiment results are analyzed in detail, giving insight into the performances of the system. Studies show that the energy-saving and environmental protection performances of the system can be significantly promoted by using the improved thermodynamic cycle.

Dynamic Analysis of the Single Piston Hydraulic Free Piston Engine

2011 ◽  
Vol 48-49 ◽  
pp. 455-460
Author(s):  
Hao Ling Ren ◽  
Hai Bo Xie ◽  
Hua Yong Yang
Keyword(s):  
Compression Ratio ◽  
Control Valve ◽  
The Body ◽  
Piston Engine ◽  
Free Piston ◽  
Spring Rate ◽  
Body Vibration ◽  
Switch Time ◽  
Free Piston Engine ◽  
The Right

The connection of the engine body and the base was simplified as a spring and a damper to analyze the body vibration of the single piston hydraulic free piston engine. It was demonstrated that the increasing of the connection spring rate can reduce the amplitude of the body vibration. But the reduced vibration amplitude was trivial after the spring rate was increased above 300KN/m. The damp ratio of the connection had little influence on the body vibration. The introduction of a pump chamber into the structure in the compression stroke can shorten the rebounding displacement of the free piston assembly (FPA) while it was settled at the right dead center working in pulse pause modulation (PPM) mode. Furthermore it can keep the FPA have an enough stroke to achieve a predetermined compression ratio and reduce the fluctuation of the pump flow. The compression ratio can be improved through increasing the pressure of the compression accumulator and decreasing the pressure of the high pressure accumulator. Also the compression ratio and the operation frequency of the engine can be improved by shortening the switch time of the control valve and prolonging the open time.

Realizing Trajectory-Based Combustion Control in a Hydraulic Free Piston Engine via a Fast-Response Digital Valve

2018 ◽  
Author(s):  
Chen Zhang ◽  
Zongxuan Sun
Keyword(s):  
Chemical Kinetics ◽  
Thermal Efficiency ◽  
Fast Response ◽  
Combustion Control ◽  
Piston Engine ◽  
Free Piston ◽  
Frictional Loss ◽  
Switching Strategy ◽  
Hcci Combustion ◽  
Free Piston Engine

Previously, the authors have proposed the concept of piston trajectory-based combustion control enabled by a free piston engine (FPE) and shown its advantages on both thermal efficiency and emissions performance. The main idea of this control method is to design and implement an optimal piston trajectory into FPE and optimizes the combustion performance accordingly. To realize the combustion control in practice, it is obvious that the design of the optimal trajectory should consider the dynamic behaviors of the FPE’s actuation systems as well as variable load dynamics and fuels’ chemical kinetics. In this paper, a comprehensive model describing the operation of a hydraulic FPE fueled by diesel under HCCI combustion mode is developed. Such a high fidelity model includes four parts, i.e. the piston dynamics, the hydraulic dynamics, the thermodynamics and the fuel’s chemical kinetics. Extensive simulation results are produced, showing that by varying the switching strategy of a fast-response digital valve, the hydraulic FPE can operate at different working loads in a stable manner. Additionally, analysis has been conducted to quantify the thermal efficiency as well as the frictional loss and throttling loss of the FPE. At last, a feedback control is developed to generate optimal switching strategies for the digital valve aimed to achieve the HCCI combustion phasing control. The resulted switching strategy of the digital valve not only increases the thermal efficiency by 0.76%, but also reduces frictional loss by 9.8%, throttling loss by 6.5% as well as NOx emission by 85.6%, which clearly demonstrates the effectiveness of the trajectory-based combustion control.

scholarly journals Disturbance analysis of a free-piston engine generator using a validated fast-response numerical model

2017 ◽  
Vol 185 ◽  
pp. 440-451 ◽  
Author(s):  
Boru Jia ◽  
Andrew Smallbone ◽  
Rikard Mikalsen ◽  
Huihua Feng ◽  
Zhengxing Zuo ◽  
...  
Keyword(s):  
Numerical Model ◽  
Fast Response ◽  
Piston Engine ◽  
Free Piston ◽  
Free Piston Engine ◽  
Disturbance Analysis

A fast response free-piston engine generator numerical model for control applications

2016 ◽  
Vol 162 ◽  
pp. 321-329 ◽  
Author(s):  
Boru Jia ◽  
Andrew Smallbone ◽  
Huihua Feng ◽  
Guohong Tian ◽  
Zhengxing Zuo ◽  
...  
Keyword(s):  
Numerical Model ◽  
Fast Response ◽  
Piston Engine ◽  
Free Piston ◽  
Control Applications ◽  
Free Piston Engine

Study on the Starting Process Driven by Accumulator of a Hydraulic Free Piston Engine

2011 ◽  
Vol 121-126 ◽  
pp. 3092-3096
Author(s):  
Bi Zhong Xia ◽  
Gang Su ◽  
Hai Bo Xie ◽  
Hua Yong Yang
Keyword(s):  
Mathematical Model ◽  
Control Valve ◽  
Piston Engine ◽  
Free Piston ◽  
Directional Control ◽  
Free Piston Engine ◽  
Hydraulic Accumulator ◽  
Starting Process ◽  
The Mathematical Model ◽  
Directional Control Valve

Starting system plays an important role in a hydraulic free piston engine (HFPE) and hydraulic accumulator/directional control valve combination is often employed. In this paper, the starting process of a typical starting system composed of a hydraulic bladder accumulator is firstly described, and then the mathematical model of the starting system is established and analyzed as well as some special situations are discussed.

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.

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