2006 Volume 35 Issue 2 Pages 133-140
Not only small medium ships but large ships, whose engines are generally operated on low load, cruise in rivers and ports discharging various air pollution substances due to bad combustion conditions. In the past, many large ships usually stayed away from cities and the engines were operated on ordinary load, so the emission regulations did not apply to marine engines. However, in May, 2005 regulations against NOx and SOx were enacted throughout the world and apply to marine engines. Moreover, under the present conditions cheaper and lower quality oil is used in marine engines, so it can cause the discharge of NOx, SOx, particulate matters (PM) and other emissions.
In order to examine the influence that low quality oil with sulfur has on the amount of PM discharge, the laser light scattering and attenuation technique (the laser method) was established as a continuous method for measuring the diameter of a particle and concentration of PM. Various fuel oils with different amounts of sulfur were combusted in an actual diesel engine, and the product discharge properties of the PM was investigated.
The laser method proves to be a technique with very high accuracy compared to PM weight concentration through the filter method. The increase in sulfur corresponded to smaller discharge particulate diameters. However, the rise in density resulted in increased PM concentration. Similarly in 4 cycle engines, the increase in sulfur led to an increase in the insoluble organic fraction (= Dry Soot; DS) in the PM and a decrease in the soluble organic fraction (SOF) .
