A Novel Approach to Free-Piston Engine Control Using an FPGA Based Control System

2011 ◽  
Author(s):  
Matthew Viele ◽  
Eric E. Shorey ◽  
Carroll G. Dase ◽  
Karl V. Hoose ◽  
Kendrick H. Light
Keyword(s):  
Control System ◽  
Engine Control ◽  
Piston Engine ◽  
Stroke Length ◽  
Free Piston ◽  
Simple Method ◽  
Engine Control System ◽  
Bottom Dead Center ◽  
Novel Approach ◽  
Free Piston Engine

The variable stroke length of the free-piston engine poses an interesting problem for the controls engineer. At a low level, the control system must be able to track piston position and address changes in top and bottom dead center positions. To accomplish this, a new FPGA (field programmable gate array) based engine position tracking software was developed, along with a simple method of mapping from a conventional engine control system to a free-piston control system. The tracking software was integrated into a complete rapid prototyping control system that was responsible for all control actions of the engine. The control system was laboratory tested on the HiPerTEC, an opposed, free-piston engine with a circular piston arrangement (as opposed to linear free-piston engines) developed by Applied Thermal Sciences, Inc (ATS). The control system has been demonstrated to run 8 cylinders up to an effective speed of 2,200rpm in spark ignition mode.

A Virtual-Cam Control Methodology for Free-Piston Engines

2011 ◽  
Author(s):  
Chao Yong ◽  
Eric J. Barth
Keyword(s):  
Internal Combustion Engines ◽  
Control Method ◽  
Piston Engine ◽  
Piston Motion ◽  
Stroke Length ◽  
Free Piston ◽  
Physical Context ◽  
Spark Timing ◽  
Free Piston Engine ◽  
Timing Belt

In conventional internal combustion engines, valves are opened and closed using a cam surface. The cam is kinematically related to the piston positions through the crankshaft and timing belt. In contrast, there is no crankshaft or kinematic cam surface in a free-piston engine to physically realize this mechanism. As a consequence, a free-piston engine has variable stroke lengths, which presents a challenge for active piston motion and precise stroke length control. This paper presents a virtual-cam based approach to relate free-piston motion to actuated engine valve control within a clear and familiar intuitive physical context. The primary functionality of the virtual cam control framework is to create a variable index, which is adjustable from cycle to cycle, for the exhaust/injection valves and spark timing similar to the function of physical cams in conventional engines. Since the cam is virtually created, it can be dynamically rebuilt to comply with cycle-to-cycle variations such as amount of the air/fuel supply, engine load and stroke length. This index rebuilding process is based on a cycle-to-cycle adaptive control method that uses the knowledge obtained from previous cycles to adjust the cam parameters. Preliminary experimental results are presented for a novel liquid-piston free-piston engine intended as a compact and efficient energy source for untethered power dense pneumatic systems such as untethered robots.

scholarly journals Fault Diagnosis Method for Engine Control System Based on Probabilistic Neural Network and Support Vector Machine

2019 ◽  
Vol 9 (19) ◽  
pp. 4122 ◽  
Author(s):  
Bo Wang ◽  
Hongwei Ke ◽  
Xiaodong Ma ◽  
Bing Yu
Keyword(s):  
Neural Network ◽  
Support Vector Machine ◽  
Control System ◽  
Fault Diagnosis ◽  
Probabilistic Neural Network ◽  
Support Vector ◽  
Engine Control ◽  
Piston Engine ◽  
Engine Control System ◽  
Diagnosis Method

Due to the poor working conditions of an engine, its control system is prone to failure. If these faults cannot be treated in time, it will cause great loss of life and property. In order to improve the safety and reliability of an aero-engine, fault diagnosis, and optimization method of engine control system based on probabilistic neural network (PNN) and support vector machine (SVM) is proposed. Firstly, using the German 3 W piston engine as a control object, the fault diagnosis scheme is designed and introduced briefly. Then, the fault injection is performed to produce faults, and the data sample for engine fault diagnosis is established. Finally, the important parameters of PNN and SVM are optimized by particle swarm optimization (PSO), and the results are analyzed and compared. It shows that the engine fault diagnosis method based on PNN and SVM can effectively diagnose the common faults. Under the optimization of PSO, the accuracy of PNN and SVM results are significantly improved, the classification accuracy of PNN is up to 96.4%, and the accuracy of SVM is up to 98.8%, which improves the application of them in fault diagnosis technology of aero-piston engine control system.

Determination of TDC in a hydraulic free-piston engine by a novel approach

2014 ◽  
Vol 70 (1) ◽  
pp. 524-530 ◽  
Author(s):  
Zhenfeng Zhao ◽  
Fujun Zhang ◽  
Ying Huang ◽  
Changlu Zhao
Keyword(s):  
Piston Engine ◽  
Free Piston ◽  
Novel Approach ◽  
Free Piston Engine

Modeling of Piston Trajectory-Based HCCI Combustion

2014 ◽  
Author(s):  
Chen Zhang ◽  
Ke Li ◽  
Zongxuan Sun
Keyword(s):  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Combustion Process ◽  
Gas Temperature ◽  
Piston Engine ◽  
Free Piston ◽  
Active Motion ◽  
Motion Patterns ◽  
Bottom Dead Center ◽  
Free Piston Engine

Previously, the authors have designed and implemented an active motion control “virtual crankshaft” for a free piston engine, which enables precise piston tracking of desired trajectories. With this mechanism, the volume of the combustion chamber can be regulated, and therefore the pressure, temperature and species concentrations of in-cylinder gas can be adjusted in real-time which affect the combustion process directly. This new degree of freedom enables us to conduct trajectory-based combustion control. In this paper, a model of the free piston engine running homogeneous charge compression ignition combustion under variant piston trajectories is presented. The variant piston trajectories have the ability to change the compression ratio and accommodate different piston motion patterns between the top dead center and the bottom dead center. The Lawrence Livermore National Laboratory reduced n-heptane reaction mechanism is employed in the model in order to describe the chemical kinetics under various piston trajectories. Analysis of the simulation results is then presented which reveals the piston trajectory effects on the combustion phenomena in terms of in-cylinder gas temperature trace, indicated output work, heat loss and radical species accumulation process.

Design of Electronic Control System for Free-Piston Engine Generator

2014 ◽  
Vol 538 ◽  
pp. 417-420
Author(s):  
Dao Jing Wang ◽  
Yi Tong Jiang ◽  
Fu Shui Liu
Keyword(s):  
Control System ◽  
Modular Design ◽  
Electronic Control ◽  
Single Chip ◽  
Piston Engine ◽  
Free Piston ◽  
Differential Signal ◽  
Electronic Control System ◽  
Free Piston Engine ◽  
And Control

Based on Infineon XC167, an electronic control system was designed for internal combustion free piston engine generator (FPEG). The displacement was output in form of 4 channel differential signal by Coaxial magnetic grid, so the signal processing circuit was designed, and the displacement signal can be trapped by single-chip micro-controller; according to the current displacement, the ignition pulse width and ignition position was calculated by the single-chip micro-controller, ignition pulse was output; the operation parameter was monitored and control parameter was adjusted by PC. The test results show that: modular design was introduced in the design of electric control system, and it monitors and controls the FPEG accurately, the control objectives are achieved.

Development of Free Piston Engine Linear Generator System Part 2 - Investigation of Control System for Generator

2014 ◽  
Author(s):  
Shigeaki Goto ◽  
Kaznunari Moriya ◽  
Hidemasa Kosaka ◽  
Tomoyuki Akita ◽  
Yoshihiro Hotta ◽  
...  
Keyword(s):  
Control System ◽  
Piston Engine ◽  
Generator System ◽  
Free Piston ◽  
Linear Generator ◽  
Free Piston Engine ◽  
System Part

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.

scholarly journals Co-Simulation of Distributed Engine Control System and Network Model using FMI & SCNSL

2015 ◽  
Vol 48 (16) ◽  
pp. 261-266 ◽  
Author(s):  
Nicolai Pedersen ◽  
Jan Madsen ◽  
Morten Vejlgaard-Laursen
Keyword(s):  
Control System ◽  
Network Model ◽  
Engine Control ◽  
Engine Control System
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