In these years, a problem of air pollution in a global scale becomes a matter of great concern. In such social situation, diesel engines are strongly required to reduce the NOx and particulate emission in the exhaust gas. In this paper, measurements of particulate emissions from a low speed two-stroke marine diesel engine were conducted with several kinds of diesel oil and a heavy fuel oil, to know the characteristics of particulate emissions at the present situation. The effects of engine load and sulfur content of the fuel on the particulate emission have been examined. The particulate emission from the test engine was measured by partial-flow dilution tunnel system, and particulate matter collected on the filter was divided into four components, SOF (soluble organic fraction), sulfate, bound water and dry soot, by Soxlet extraction and ion chromatograph. Results show that the particulate emission from the test engine operated with heavy fuel oil is three times as much as the value with diesel oil and that not only sulfate but SOF and dry soot concentration increase with the increase in fuel sulfur content. It is also found that the conversion rate from sulfur in fuel into sulfate in particulate matter is nearly independent of the sulfur content in the fuel and increases with the increase in the engine load.
The Effect of Emulsified Fuel Oil Combustion on Marine Diesel Engine