• Title/Summary/Keyword: Marine diesel engines

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Speed Control of Marine Diesel Engines Using Fuzzy Scheduling (퍼지게인 스케줄링을 이용한 선박용 디젤기관의 속도제어)

  • 유성호
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2000.05a
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    • pp.1-5
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    • 2000
  • The conventional PID controller has been extensively used to speed control of marine diesel engines. However one of drawbacks is that its control performance can be degraded if the parameters are fixed on whole operating points. In this paper a scheme for integrating PID control and the fuzzy technique is presented to control speed of a marine diesel engine on whole operating points. At first the PID controller is designed at each speed mode whose parameters are optimally adjusted using a genetic algorithm, Then fuzzy "if-then" rules combine the controllers as a consequence part. To demonstrate the effectiveness of the proposed fuzzy controller a set of simulation works on a marine diesel engine are carried out.rried out.

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Design of an Intelligent Speed Control System for Marine Diesel Engines (선박용 디젤엔진을 위한 지능적인 속도제어시스템의 설계)

  • J.S.Ha;S.J.Oh
    • Journal of Advanced Marine Engineering and Technology
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    • v.21 no.4
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    • pp.414-420
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    • 1997
  • An intelligent speed control system for marine diesel engines is presented. The approach adopt¬ed is to use a conventional PID controller for normal operation and a feedforward controller for adaptive control. The feedforward controller is a neural network. The neural network is the inverse dynamics model of the plant, which is being trained on line. The parametric model of the diesel engine is represented in a linear second-order system, with a first-order combustion part and a revolution part each at a normal operating point. The time delay in the control of the com¬bustion part is approximated to the first-order system. The tuned PID parameters are set based on the model for normal operating point. To obtain the inverse dynamics of the diesel engine system, two neural networks are used, one for inverse, the other for forward dynamics. The former is posi¬tioned across the plant to learn its inverse dynamics during operation, and the latter is placed in series with the controlled plant. Simulation results are presented to illustrate the applicability of the proposed scheme to intelligent adaptive control of diesel engines.

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A Study on Optimal Combustion Conditions with a Design and Manufacture of the Long-Stroke Slow Speed 4 Cycle Diesel Engine (장-행정 저속 4 사이클 디젤기관의 제작 및 최적 연소조건에 관한 연구)

  • 장태익
    • Journal of Advanced Marine Engineering and Technology
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    • v.28 no.3
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    • pp.551-558
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    • 2004
  • Recently, fuel prices have been continually raised in diesel engine. Such a change in the fuel price influences enormously the development trend of marine diesel engines for slow speed, In other words, the focus was shifted from large diameter and high speed to low fuel consumption. Accordingly, more efforts are being made for engine manufacturing and development to develop highly efficient engines. In this study. a single cylinder 4 stroke cycle DI slow speed diesel engine was designed and manufactured, a 4 stroke cycle was configured and basic performances were evaluated. The results are as follows. The optimal fuel injection timing had the lowest value when specific fuel consumption was in BTDC 8~$10^{\circ}$, a little more delayed compared to high speed diesel engines. Cycle variation of engines showed about 5% difference at full loads. This is a significantly small value compared to the cycle variation in which stable operation is possible, showing the high stability of engine operation is good. The torque and brake thermal efficiency of engine increased with an increase of engine 250-450 rpm. but fuel consumption ratio increased from the 450 rpm zone and thermal efficiency abruptly decreased. Mechanical efficiency was maximally 70% at a 400 rpm that was lower than normal engines according to the increase of mechanical frictional loss for cross head part. The purpose of this study was to get more practical engines by comparing the above results with those of slow speed 2 stroke cycle diesel engines.

Numerical and Theoretical Study on the Fluid Flow in the Cooling System of a Marine Diesel Engine (선박용 디젤엔진의 냉각수 유동에 대한 수치해석적 및 이론적 연구)

  • Suh, Yong-Kweon;Heo, Seong-Gyu;Chung, Sung-Sik
    • Journal of Advanced Marine Engineering and Technology
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    • v.32 no.1
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    • pp.119-130
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    • 2008
  • Diesel engine is one of the most expensive and important components in a ship. Many researchers are interested in increasing the performance of diesel engines. Design of an optimum cooling system should also contribute to the enhancement of the performance as well as the efficiency of engines. In this study, we investigated the flow pattern within the cooling system of a marine diesel engine by using numerical simulation prior to the study of the heat-transfer problem. The engine cooling system is composed of five cooling units each unit containing a water-jacket and a cylinder head. Based on the calculated data, we also conducted theoretical analysis that can predict the flow-rate delivery in each of the five units.

Effects of SO2 Mixture in Inlet Air on Combustion and Exhaust Emission Characteristic in diesel engine (디젤엔진에 있어서 흡기 중에 SO2혼입이 연소 및 배기배출물 특성에 미치는 영향)

  • Yoo, Dong-Hoon
    • Journal of Power System Engineering
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    • v.19 no.2
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    • pp.64-69
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    • 2015
  • Marine diesel engines with high thermal efficiency and fuel diversity used for propulsive power have been taking charge of important position on marine transport. However, marine environment has recently focused on emissions such as nitrogen oxide and sulfur oxide which is generated from combustion of low grade fuels. EGR(Exhaust gas recirculation) system is one of effective methods to reduce the nitrogen oxide emission from marine diesel engines. In general, it is considered that recirculating gas influences fuel combustion and emissions in diesel engines. However, along with positive effects of EGR, the EGR system using fuels of including high sulfur concentration should be considered about re-combustion and activation of sulfur dioxide in recirculating gas. Therefore, in experimental study, an author investigates effects of sulfur dioxide mixture concentration in intake air on combustion and exhaust emission characteristics in a direct injection diesel engine. In results, change of sulfur dioxide concentrations in intake air had negligible impact on combustion chamber pressure, rate of heat release and emissions compared with effects of oxygen decreasing and carbon dioxide increasing of EGR.

Vibration Control of Engine Body for Two Stroke Low Speed Diesel Engine using Dynamic Vibration Absorber (동흡진기에 의한 저속 2행정 디젤엔진의 본체진동 제어)

  • 이돈출;유정대;김정렬
    • Journal of Advanced Marine Engineering and Technology
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    • v.26 no.6
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    • pp.631-637
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    • 2002
  • Two stroke low speed diesel engines are used as a power supplier not only for marine vessel but also diesel power plant with a benefit of its higher mobility and durability than the other thermal engines. However, there are some disadvantages such as the bigger vibrating excitation forces generated by high combustion pressure in cylinders which various kinds of vibrations are caused. In this paper, it is theoretically studied to control engine body vibration using dynamic vibration absorber. As an actual case, dynamic absorbers are designed for controlling X-mode vibration of 9K80MC-S engine on the diesel power plant and its performance is identified by the vibration test both in shop and site

Simulation of the Gas Exchange Process in a Two - Stroke Cycle Diesel Engine (2행정 사이클 디젤기관의 가스교환과정 시뮬레이션)

  • 고대권;최재성
    • Journal of Advanced Marine Engineering and Technology
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    • v.18 no.2
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    • pp.104-112
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    • 1994
  • The scavenging efficiency has a great influence on the performance of a diesel engine, especially slow two-stroke diesel engines which are usually used as a marine propulsion power plant. And this is greatly affected by the conditions in the cylinder, scavenging manifold and exhaust manifold during the gas exchange process. There are many factors to affect on the scavenging efficiency and these factors interact each other very complicatedly. Therefore the simulation program of the gas exchange process is very useful to improve and predict the scavenging efficiency, due to the high costs associated with redesign and testing. In this paper, a three-zone scavenging model for two-stroke uniflow engines was developed to link a control-volume-type engine simulation program for performance prediction of long-stroke marine engines. In this model it was attempted to simulate the three different regions perceived to exist inside the cylinder during scavenging, namely the air, mixing and combystion products regions, by modeling each region as a seperate control volume. Finally the scavenging efficiency was compared with three type of scavenging modes, that is, pure displacement, partial mixing and prefect mixing.

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A Study on the Thoretical Analysis of the Torque Harmonics for Diesel Engines (디젤기관의 토크 하모닉스에 대한 이론적 해석)

  • 이용진;장민오;김의간;전효중
    • Journal of KSNVE
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    • v.10 no.3
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    • pp.465-473
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    • 2000
  • In this crankshaft of marine diesel engines the exciting torques are produced by gas pressure and reciprocating masses. These torques are periodically changing and are extremely out of balance. To calculate the torsional vibrations of propulsion shafting caused by unbalanced torque the torque harmonics are utilized. Until now to calculate the torsional vibrations of propulsion shafting. the torque harmonics have been supplied by the engine maker. When the torque harmonics of an engine are not available the torque harmonics of a similar engine type had to be used. However such data is not suitable for the reliable calculations of torsional vibrations. In this paper the combustion characteristics of marine diesel engines including $\rho{-}\upsilon$ diagram are investigated and the torque harmonics based on these are theoretically calculated. reliability of the calculations is confirmed by comparing them with those of an engine maker. This study should prove useful for the calculations of torsional vibrations for diesel engine propulsion shafting. particularly for 4-stroke engines whose torque harmonics are difficult to obtain directly from the engine and not ordinarily supplied by the engine maker.

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A Study on the NOx Emission Status and Reduction Technologies of Domestic Marine Engine (국내 선박 엔진의 NOx 배출현황 및 저감기술 개발에 관한 고찰)

  • Kang K. J.;Kim S. H.;Kim E. C.
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.7 no.2
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    • pp.57-63
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    • 2004
  • In this paper, the NOx emission and the reduction technologies of NOx emission for domestic marine diesel engine were investigated. At first, the present production status of domestic marine diesel engines was investigated. In the next, the NOx emission of domestic marine diesel engines was investigated. Finally, the present status of a reduction technologies of NOx emission was investigated. From this investigation, It could be founded that the domestic marine diesel engines satisfied the IMO current NOx regulations, however the higher technologies must be studied to prepare the more severe IMO regulations of the near future.

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