Use of electronic control for large marine diesel engines is rapidly increasing because of predicted high demand for environmental friendliness, lower operating costs, added maintenance provisions, and compliance with stricter emission limits. The UEC Eco-Engine, based on experience with research engines and a full-scale prototype engine, satisfies all these objectives. The first full-scale Eco-Engine, the 7UEC33LSII-Eco, has proven its relia-bility and performance in various types of operation as a stationary diesel generating set over the past two and a half years at the Kobe Shipyard & Machinery Works of Mitsubishi Heavy Industries. In the middle of 2005, the first commercial UEC Eco-Engine, the 8UEC60LSII-Eco, will enter service in a pure car and truck carrier.
Middle speed diesel engine (EcoDiesel SAVETEN) was developed in order to achieve very low fuel consumption and meet the IMO NOx regulation. Generally, the fuel consumption and smoke generation should be increased when NOx emission is reduced. This also means that the production of CO2 (a so-called green house gas) will increase. This is one of the most difficult subjects on engine development. But EcoDiesel SAVETEN has realized“lower fuel consumption”and“lower NOx emissions”at the same time, without causing a increase in smoke emission. We thought out a new combustion concept for lower fuel consumption without increasing maximum cylinder pressure and injection pressure by using a simplified cyclic simulation. In order to realize the new combustion concept, the newly designed fuel injection system, combustion chamber and intake&exhaust system were applied. This com-bustion system is called the ASSIGN (Available Space Scattering Injection Geometric Nexus) combustion system. This realized the 10g/kWh lower fuel consumption than the conventional engines on the equivalent NOx emissions. And this is applied to the marine auxiliary diesel engines from 360kW to 3500kW.This is one of the YANMAR' s solutions for the marine environmental protection.
Carbon dioxide (CO2) ocean sequestration technologies, such as dissolution into seawater, are important to promote protection of the global environment. In this study, the solution process of CO2gas in seawater and pure water was experimentally studied under various pressures and temperatures to evaluate the solubilities of CO2in seawater. The solubilities of CO2in seawater and pure water were measured by the change in pressure due to absorption at pressures up to 1500 kPa and temperatures ranging from 20°C to 60°C. We found that the solubilities of CO2were between 0.27×10-3and 5.45×10-3in seawater, and between 0.26×10-3and 0.6×10-3in pure water near atmospheric pressure. They increase with an increase in pressure, but decrease with an increase in temperature. The Henry's law constant of CO2was about 200 MPa at a temperature of 20°C in seawater under 500 kPa, and increased with an increase in temperature. The solubility of CO2in seawater was lower than that in pure water. We obtained empiri-cal correlations for solubilities of CO2in seawater and pure water at various temperatures under atmospheric pressure, based on the experimental data.
Using emulsified fuel, with water particles dispersed in the continuous phase of fuel, is effective in suppressing the emission of polluting matter from spray combustors, such as diesel engines and boilers. This paper discusses the emission characteristics and the performance of a marine four-stroke diesel engine operated with emulsified fuels having different water particle diameters. The research especially focused on how the PM (Particulate Matter) and NOx (Nitrogen Oxide) emission was affected by the water particle diameter in emulsified fuel. In the engine experiment, we used Marine Diesel Fuel (MDF) in three emulsified fuels having mean water particle diameters of 3.94μm, 7.71μm, and 8.78μm. The following results were found: 1. In comparison with using MDF, the emission level was decreased by about 10% to 40% by using emulsified fuels, and the smaller the mean water particle diameter of the emulsified fuel, the lower the NOxemission level. 2. The PM, SOF (Soluble Organic Fraction), and ISF (Insoluble Organic Fraction) emission rates increased with use of emulsified fuel, especially in the low load area. 3. The SFC (Specific Fuel Consumption) of emulsified fuel having the largest mean water particle diameter in this experiment was lower than that of the MDF. Among the three emulsified fuels, the smaller the mean water particle diameter, the higher the SFC.