The severe sulfur regulation of marine fuels is now discussed to reduce the emission of SOx, NOx and PM from ships for the purpose of the environmental protection on the ocean in IMO (International Maritime Organization/MEPC (The Marine Environment Protection Committee) /BLG (Bulk Liquids and Gases) . The severest proposal is that all marine fuels will be switched to the distillate and the sulfur contents will be reduced to 1.0mass% until 2012 and to 0.5mass% until 2015. However, if this severe proposal will be adopted, some issues concerning the supply capacity of low-sulfur marine fuels and the balance between heavy oil's supply and demand will be raised. Then, it is necessary to discuss carefully the measures to be taken. This paper presents the trends of sulfur regulation of marine fuels in IMO, the production methods of low-sulfur marine fuels, the proposal (Prevention of air pollution from ships) endorsed in MEPC, 56th and the outline of the investigation plan about the forecast of heavy oil's supply and demand, influence of the environment, etc, by JPEC (Japan Petroleum Energy Center) .
The fuel injection system is one of the most important parts of the diesel engine. In this paper, it reports the history and features of fuel injection systems which were installed on the modem typed marine large two strokes cycle low speed diesel engines. The famous recent three brands have been adopted different typed fuel injection systems on their diesel engines. One is good controllable type, another is simple construction. What did the engineers consider when they developed them? Recently, the fuel injection is controlled by electronic devices. The control ability is increased and we can control not only fuel injection but also fuel oil consumption, NOx emission and smoke. The electronic control fuel injection system removed mechanical devices such as gear train, cam and roller, camshaft, linkage and governor from the diesel engine. This movement is influenced to the exhaust valve driving system, starting air control system and cylinder lubricating system which were moved by the camshaft. The diesel engine will change more from the fuel injection system.
This technical paper deals with a general introduction of the fuel injection system on the Mitsui-MAN B&W engine. There are two different fuel injection systems, one is driven by a mechanical camshaft used in conventional MC/MC-C engines, and the other is the electrically controlled hydraulic system as used by ME/ME-C engines. Due to strict requirements with regards emissions, as well as for the safety of the ship, the electrically controlled hydraulic fuel injection system will become more and more popular in the future of marine two-stroke engines. We consider this fuel injection system to optimize the NOx emission, and also the emission of other greenhouse gases. It must be a key technical factor of engine development in the future.
Machines and equipments are arranged functionally in a ship's engine room; the generation of the ship's propulsion power, supplying electricity, refrigeration, air conditioning and so on. Such machines and equipments are usually manufactured in different companies. Meanwhile, the rapid development of the shipbuilding technologies in some Asian countries is starting to threaten the marine engineering industries in Japan. In this paper, a new design methodology - defined as Concurrent Marine Engineering (CME) -is proposed to cope with this situation. As an actual outcome, CME is aimed at manufacturing engine rooms with high competency through the cooperation among the different Japanese companies related to marine engineering. We wish to provide an environment of Sustainable Developing Marine Engineering.
An investigation was made into the deformation of a cylinder liner used in a large crosshead diesel engine. This deformation was calculated, but also measured. The results were then compared. They were not perfectly coincidental. The reason for the discrepancy is considered as applying the axis symmetrical model to a cylinder block being a complicated shape, inaccurate temperature distribution and improper modeling of the contact surfaces of the parts.
An experimental investigation on the combustion of emulsions in small pool burners has been carried out. The base fuel used was kerosene. The water content varied from zero to 30% by volume and by volume surfactant 2% was used. Stainless steel tubes of diameterφ 9.5, φ13 and φ16 were used for the burner. Coiled copper tubes (φ2) were attached to the top of each burner, so to control the burner wall temperature by cooling water which passes through the copper tubes. In order to make emulsions burn quasi-steadily and form a laminar diffusion flame, accompanied with evaporating of water in the emulsion, the burner wall temperature was maintained from 115°C to 120°C. Results show that the yellow point (fuel flow rate of onset of carbon luminosity) and sooting point (fuel flow rate of soot just formed) increase. The maximum burning point (fuel flow rate at beginning of fuel overflow from burner rim) decreases with the increase of the water content. The Booting rate (mass of collected soot/mass of burned fuel) decreased with the increase in the water content. The corrected sooting rate (mass of collected soot/mass of burned kerosene) of the emulsions were lower than that of the neat kerosene.
The previous report described the corrosive wear on propeller shaft sleeves, made of bronze, in seawater-lubricated stem tube bearings. Accompanying is the occurrence of craters on the sleeve surface due to the action of erosion corrosion. As a countermeasure, based on the mechanism, this second report will provide the development of a catholic protection bearing, what prevents corrosion of the sleeve surface and reduces wear. Using anodes installed in some of the water channel grooves of the rubber bearings, this method is characterized by intermittent protection at best, and protection conditions were investigated by means of fundamental testing and using bearings of 140mm in diameter. As a result, a current density of 8A/m2 was found to protect the sleeve from corrosive wear. Cathodically protected bearings were also applied to bearings of 500mm in diameter and equipped for a ferry vessel. The results are presented here in terms of bearing design, trial running, and successful reduction of wear during actual in-service use.
Effects of the split injection pattern on combustion and emission characteristics of a D.I. Diesel engine with a common-rail injection system were investigated. While keeping the injection pressure and total injection quantity constant, a ratio of amounts of fuel injected between two injection pulses and the injection interval were varied. The in-cylinder pressure was analyzed, and the characteristics of the combustion process were discussed with the engine-out measurements. The concentration distributions of the vapor and liquid phases in the splitting fuel spray injected into a high-pressure/high-temperature vessel were measured by means of the Laser Absorption Scattering (LAS) technique. The mixture properties obtained by the LAS measurements were correlated with the characteristics of the combustion process. The results account for the effects of the split injection pattern on the combustion and emission characteristics.
The developing and mixing characteristics of a diesel spray were investigated, and under circumstances of changing fuel injection and the ambient gas conditions. The mixing measurement in the diesel spray was conducted using planar laser Rayleigh scattering. Experiments were conducted in an optically accessible, constant-volume combustion chamber. The chamber could simulate the ambient conditions of a typical diesel engine. In this study n-heptane was injected into the chamber and the scattered light from the spray was detected by an ICCD camera. A 532 nm Nd: YAG laser was used as a light source. The experimental results show that an injection pressure has a great effect on fuel vaporizing and in the mixing. Also, an increase in the injection pressure could promote a much leaner fuellambient gas mix. The results showed that an ambient temperature and density do have a great effect on the vaporization of fuel droplets and a development of liquid length in the diesel spray.