scholarly journals Numerical Investigation of a Free-Piston Hydrogen-Gasoline Engine Linear Generator

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4685
Author(s):  
Ziwei Zhang ◽  
Huihua Feng ◽  
Zhengxing Zuo
Keyword(s):  
Negative Correlation ◽  
Volume Fraction ◽  
Control Variable ◽  
Cylinder Pressure ◽  
Ignition Timing ◽  
Piston Engine ◽  
Piston Velocity ◽  
Free Piston ◽  
Linear Generator ◽  
Free Piston Engine

The free-piston engine linear generator (FPELG) is being investigated by many researchers because of its high thermal efficiency and its variable compression ratio. However, all researchers focused on the FPELG characteristics with mono-fuel. Therefore, in this paper, the performance of the FPELG that has adopted gasoline with hydrogen as fuel is investigated. The method of coupling the zero-dimensional dynamics model with the multi-dimensional CFD (Computational Fluid Dynamics) combustion model was applied during the simulation process. According to the results, the piston TDC (Top Dead Center), the piston peak piston velocity, and the system operation frequency show a negative correlation with the increase of hydrogen fractions. However, the peak in-cylinder pressure was increased with the hydrogen volume fraction increase, due to the fast flame speed and short combustion duration characteristics of hydrogen. Meanwhile, the indicated efficiency of the free-piston engine was increased from 32.3% to 35.3% with the hydrogen volume fraction change from 0% to 4.5%, when the free-piston engine operates at stoichiometric conditions with fixed ignition timing. In addition, with the ignition timing advance increase, the piston TDC was decreased. The peak piston velocity and the peak in-cylinder pressure were in negative correlation with the ignition timing advance. While the engine indicated that the efficiency was increased with the equivalent degree of ignition timing from 20° to 16°. Therefore, the ignition timing of the FPELG under the spark-ignition combustion mode is supposed to be an effective and practical control variable.

State Estimation Algorithm Based on a Disturbance Observer for a Free-Piston Engine Linear Generator

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Shigeaki Goto ◽  
Kazunari Moriya ◽  
Hidemasa Kosaka ◽  
Tomoyuki Akita ◽  
Yoshihiro Hotta ◽  
...  
Keyword(s):  
Estimation Algorithm ◽  
Position Sensor ◽  
Ignition Timing ◽  
Piston Engine ◽  
Free Piston ◽  
Linear Generator ◽  
Free Piston Engine ◽  
Lubrication Condition ◽  
Power Generation System ◽  
Piston Position

In order to realize a thin, compact, efficient, and fuel-flexible power-generation system, we have been developing and investigating a free-piston engine linear generator (FPEG), which consists of a two-stroke combustion chamber and an adjustable gas spring chamber. This paper proposes a novel observer algorithm that has two advantages. First, the piston position can be interpolated at high accuracy beyond the resolution of the piston position sensor, which improves the accuracy and stability in controlling the combustion parameters, such as ignition timing and compression ratio. Second, the pressure in the gas spring chamber and the coefficient of damping (lubrication condition) are estimated simultaneously and independently. In this paper, the principle of the developed observer algorithm is described and tested through simulation and experimentation using the developed FPEG system. Based on the simulation, the output of the position sensor (resolution: 0.55 mm) was interpolated with an accuracy of ±0.1 mm. Based on the experimental results for the estimation of pressure in the gas spring chamber and the coefficient of damping, the feasibility of sensorless monitoring of the pressure in the gas spring chamber and the coefficient of damping has been verified.

Modeling and Design of a Tubular Linear Generator for Direct-Drive Free-Piston Engine

2021 ◽  
Author(s):  
Christophe S. Cyusa ◽  
Tamanwe Payarou ◽  
Dwaipayan Barman ◽  
Tamas Bertenyi ◽  
Philip Raphals ◽  
...  
Keyword(s):  
Direct Drive ◽  
Piston Engine ◽  
Free Piston ◽  
Linear Generator ◽  
Free Piston Engine

scholarly journals Design considerations of a linear generator for a range extender application

2015 ◽  
Vol 64 (4) ◽  
pp. 581-592
Author(s):  
Un-Jae Seo ◽  
Björn Riemer ◽  
Rüdiger Appunn ◽  
Kay Hameyer
Keyword(s):  
Electric Vehicle ◽  
High Efficiency ◽  
Piston Engine ◽  
Free Piston ◽  
Full Load ◽  
Linear Generator ◽  
Design Considerations ◽  
Range Extender ◽  
Free Piston Engine ◽  
Linear Generators

Abstract The free piston linear generator is a new range extender concept for the application in a full electric vehicle. The free piston engine driven linear generators can achieve high efficiency at part and full load which is suitable for the range extender application. This paper presents requirements for designing a linear generator deduced from a basic analysis of a free piston linear generator.

Development of free piston engine linear generator system and a resonant pendulum type control method

2020 ◽  
pp. 146808742093124
Author(s):  
Hidemasa Kosaka ◽  
Tomoyuki Akita ◽  
Shigeaki Goto ◽  
Yoshihiro Hotta
Keyword(s):  
Control Method ◽  
Experimental Result ◽  
Piston Engine ◽  
Piston Motion ◽  
Generator System ◽  
Free Piston ◽  
Linear Generator ◽  
Reference Profile ◽  
Cycle Simulation ◽  
Free Piston Engine

A free piston engine linear generator, which has the potential of the compact physique, high brake efficiency and high flexibility for fuel, has been developed. The developed free piston engine linear generator consists of a two-stroke combustion unit, an air-bounce chamber and a linear generator. The key technologies to realize the continuous operation are the control method and lubricating and cooling strategies. The proposed structure is featured as a piston shape with two different diameters coaxially, called a “W-shape” piston, which has an empty space inside for the oil cooling path. The performance of the structure is evaluated by a one-dimensional cycle simulation. The result indicates the possible output power of 10 kW and thermal efficiency of 42% using premixed charge compression ignition combustion strategy. The control method is another challenge of the free piston engine linear generator. This work proposes two strategies of the position feedback control method and the resonant pendulum type control method. The first method has the function of the feedback loops for the piston position and velocity so that the piston motion follows the reference profile calculated in advance. The experimental results show the limited range of operation because the fixed profile does not absorb the deviation of the piston motion due to the combustion deviation. The second method is based on the speed control without a fixed reference profile of the piston motion. The experimental result shows the robustness to the change in operating parameters such as ignition position, amount of fuel and desired power output.

scholarly journals Tribological Characteristics of Piston Ring in a Free-piston Engine for Linear Generator

2014 ◽  
Vol 61 ◽  
pp. 979-983 ◽  
Author(s):  
Chenheng Yuan ◽  
Huihua Feng ◽  
Zhengxing Zuo ◽  
Yanxiao Li
Keyword(s):  
Piston Ring ◽  
Tribological Characteristics ◽  
Piston Engine ◽  
Free Piston ◽  
Linear Generator ◽  
Free Piston Engine

scholarly journals Stable Operation and Electricity Generating Characteristics of a Single-Cylinder Free Piston Engine Linear Generator: Simulation and Experiments

Energies ◽  
2015 ◽  
Vol 8 (2) ◽  
pp. 765-785 ◽  
Author(s):  
Huihua Feng ◽  
Yu Song ◽  
Zhengxing Zuo ◽  
Jiao Shang ◽  
Yaodong Wang ◽  
...  
Keyword(s):  
Stable Operation ◽  
Piston Engine ◽  
Free Piston ◽  
Single Cylinder ◽  
Linear Generator ◽  
Free Piston Engine

An Investigation on Power Generation Characteristics of Linear Generator Driven by a Free-piston Engine

2021 ◽  
Author(s):  
Nguyen Huynh Thi ◽  
Nguyen Van Trang ◽  
Huynh Thanh Cong ◽  
Dao Huu Huy ◽  
Huynh Van Loc ◽  
...  
Keyword(s):  
Power Generation ◽  
Piston Engine ◽  
Free Piston ◽  
Linear Generator ◽  
Free Piston Engine
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