Low-speed Marine Diesel Engine Research Articles

대형마찰용접을 이용한 로타샤프트 제조공정개발

Inertia welding is a solid-state welding process in which butt welds in materials are made in bar and in ring form at the joint face, and energy required for welding is obtained from a rotating flywheel. The stored energy is converted to frictional heat at the interface under axial load. The quality of the welded joint depends on many parameters, including axial force, initial revolution speed and energy, amount of upset, working time, and residual stresses in the joint. Inertia welding was conducted to make the large rotor shaft for low speed marine diesel engine, alloy steel for shaft of 140mm. Due to material characteristics, such as, thermal conductivity and high temperature flow stress, on the two sides of the weld interface, modeling is crucial in determining the optimal weld parameters. FE simulation is performed by the commercial code DEFORM-2D. A good agreement between the predicted and actual welded shape is observed. It is expected that modeling will significantly reduce the number of experimental trials needed to determine the weld parameters.

Particulate Emissions from a Low-Speed Marine Diesel Engine

This study presents results from tail pipe emissions of particulate matter from a turbocharged common rail 2-stroke marine diesel engine (4RTX-3 from Wartsila) investigated at various operating conditions and using two different fuels. Size distributions were measured with a SMPS (Scanning Mobility Particle Sizer). A thermodesorber (TD) was applied to remove volatile material. In addition, filter samples were taken for gravimetric and chemical analysis. The mean diameters of the particles ranged between 20–40 nm, which is considerably smaller than the diameter of particles known from 4-stroke diesel engines as used in cars. A TD operated at 400°C evaporated the majority of the particles. The particle mass is dominated by volatile organic material, the fraction of which is significantly higher than for engines in cars. A high nucleation mode was found instead of a pronounced accumulation mode as known from 4-stroke diesel engines.

K-2020 舶用低速ディーゼル機関の亜酸化窒素排出濃度の計測(S25-3 エンジン諸現象の計測(2))(S25 エンジンの潤滑および諸現象の計測と構成要素)

K-2020 舶用低速ディーゼル機関の亜酸化窒素排出濃度の計測(S25-3 エンジン諸現象の計測(2))(S25 エンジンの潤滑および諸現象の計測と構成要素)

ニサイクル舶用低速ディーゼル機関の諸元解析<SUP>*</SUP>

ニサイクル舶用低速ディーゼル機関の諸元解析<SUP>*</SUP>

舶用低速ディーゼル機関ピストンリグの初期なじみ特性に関する研究

Low-speed marine diesel engines are operated under severe lubricating conditions with higher output, and their lubrication is an important factor for their successful operation. In order to raise the reliability of the ring-liner lubrication of marine diesel engines, authors conducted the studies on the initial running-in methods of the ring in the stage of shop trial by measuring the oil film electrical resistance between the ring and the liner.This paper describes the feature and its mechanism of the initial running-in of the top ring, and the effective running-in method by the variation of the load to obtain good lubricating condition of the top ring during a shorter time. And it also describes the applicable region of the evaluation method of the ring-liner lubrication by the electric method.

ニサイクル舶用低速ディーゼル機関の諸元解析

When developing new engines, it is always an important subject for designers to realize lightweight and compactness while ensuring required performance and reliability of engines. Factors which contribute to the lightweight and compactness of engines are considered to roughly be classified into two. One is a factor related to engine particulars and the other is a factor related to engine structure.Once the authors proposed a method of estimating engine weight using numerical formulas into which related principal particulars were incorporated to this society.This paper reported the results of analysis on the degree of contribution of the above-mentioned two factors by this method paying attention to actual data on the realization of the lightweight and compactness of two-stroke low-speed marine diesel engines which have been developed to date.These results of analysis are considered to become useful references for establishing the target values of lightweight and compactness when new engines are developed in future.

Determination of optimum principal particulars for two-stroke cycle, low-speed marine diesel engines.

A rational and efficient method of selecting optimum principal particulars of two-stroke, low-speed marine diesel engines in the early stage of planning during development has been developed. Its effectiveness has been investigated in this study. When planning diesel engines, selection of the optimum principal particulars is desirable, which meet the user's needs and market trends and can maintain a good balance in the performance and production cost aspects, ensuring reliability. The authors have developed a simulation method to estimate the precise production cost, which is one of the most important factors for selection, in the stage before making the drawings, and have established the method of selecting optimum principal particulars incorporating prediction of performance and evaluation of economy. This paper describes the outline of this method and reports examples of the calculations by this method.

人工知能技法による舶用ディーゼル主機関起動時の故障診断システム

This system has been developed as a subsystem of the diesel engine propulsion plant of a super-automated ship. Many conventional diagnostic expert systems involve a variety of difficult problems. A study to solve these problems has produced a failure diagnostic system applying composite/structure design, which has been used to develop traditional procedure type programming. The paper describes an approach to develop the failure diagnosis system based on a Hitachi Zosen B & W low speed marine diesel engine's startup.

The metallic soaps of naphthenic acids — Part 6

Manganese naphthenate has been utilized to improve the combustion properties of kerosine and to reduce soot content of flue gases. It is also applicable as a corrosion inhibitor in gas turbine engines using naphtha as a fuel, and can be added to fuel of these engines to minimise corrosion at high temperature and filter blocking tendency, and to modify the type of deposit formed on turbine blades so that it is less adherent and softer, especially when cyclopentadienyl manganese tricarbonyl is used as a smoke reducer. The manganese naphthenate soap has been utilized to inhibit wear in low speed marine diesel engines operating on vanadium‐containing residual‐type fuel oils, and it can be employed to reduce the ignition temperature of soot in furnaces, by as much as 200%, facilitating oxidative soot removal from, especially, oil‐fired furnaces. The addition of the product to heavy tractor oil can reduce sulpher trioxide concentration. Manganese naphthenate has been used as a catalyst to the manufacture of organo‐boran compounds for use in petrol and lubricants.

低質舶用燃料油のディーゼル燃焼の改善

This paper reports on the improvements in diesel combustion of low grade marine fuels. The presented data are on the effects of characteristics of the low grade marine fuels on the diesel combustion, on soot reduction by barium compound additives and in the burning of emulsified marine fuels, on the combustion and wear of two cracked type high viscous marine fuels; a fluid catalytic cracked bottom based oil and a visbreaker bottom based oil, in the experimental apparatuses and in a marine low speed diesel engine. The latter experimental results suggests that, in the burning of the fluid catalytic cracked bottom based oil, the silicon particles in the burnt gas are mixed in the sliding surface between cylinder liner and piston rings, the so called, it is abrasive wear, and the wear rates become large.

舶用低速ディーゼル機関における乳化燃料油の燃焼のすす生成に関する研究

The experimental results obtained from the effects of emulsified fuels, diesel oil and marine oil, on the soot formation and engine performances in the combustion of a marine low speed diesel engine are summarized as follows:(1) The emulsified fuels have a remarkable effect on the reduction of sooting ratio. The more we add water to the fuels, the more sooting ratio in the exhaust gas decreases. The minimum point of sooting ratio is being in this relation.(2) In the burning gases of emulsified fuels, the specific concentrations of carbon monoxide are more than in the original fuels. So it is suggested that the water in the emulsified fuels contributes on the water gas reaction.(3) Single soot particle measured with electron micrograph is a sphere of about 140Å in diameter and sizes are nearly same in a soot of both fuels. The swarm of soot particles is smaller in proportion to add water in emulsified fuels.(4) Ignition lags are longer in the burning of the emulsified fuels than in the original fuels, but the exhaust gas temperatures are lower. The consumptions per original fuels are little.(5) In the using of emulsified fuels, there is most fitting injection timing for the reduction of soot weight, fuel consumption and exhaust gas temperature.(6) Suction pressure has more influence in the using former fuels than latter fuels on the engine performance.(7) The volume of carbon sticked on the surface of the combustion chamber is little.From these experimental results, it is found that, in the burning of the emulsified fuels of a marine low speed diesel engine, there are remarkable effects on the reduction of sooting ratio, the consumption per original fuel and the dirt in combustion chamber. But there are problems of the corrosion of exhaust pipes and the dirt of lubricating oil by the water in emulsified fuels.

高粘度分解系重油の舶用低速ディーゼル機関における燃焼と摩耗に関する研究

高粘度分解系重油の舶用低速ディーゼル機関における燃焼と摩耗に関する研究

Microbial Corrosion Problems Associated with Engine Oils and Coolants in the Shipping Industry

AbstractOver the last ten years a number of crankcase oils in low speed marine diesel engines have suffered massive microbial infections. Associated with these infections have been severe generalised corrosion in the lubricating oil systems, deep pitting of the journals, and white metal failure in the bearings. Various factors can be shown to have contributed to the appearance of this problem, such as an increasingly nutritious diet available (from new oils and new corrosion inhibitors) and less ‘oil care’. Short term anti-microbial chemicals have been successfully introduced and long term alleviation using heat pasteurisation is the subject of intensive investigation.University College Cardiff has received samples of lubricating oils and coolants from 170 ships over the last 5 years. These samples were studied and tested for microbial contamination. The results of this study have been analysed and are presented in this paper. The results suggest that in most cases microbial infections start in the coolin...

Marine diesel engine exhaust noise1

Simplified scale models are shown to be useful for determining the low-frequency sound transfer properties of an exhaust system of a large low speed marine diesel engine. Experimental results of a full-scale system including silencers closely agree w