In the case of constant speed operation, the excess air ratio depends on the engine load and changed from 2.6 at 30% load to 1.6 at 100% load. The reason of the large amount of SOF emission at low loads is thought that the lean mixture zone is easy to be produced due to the increase of excess air ratio. For two-stroke engine, since the excess air ratio did not largely change even if the operation mode is changed, the particulate emission indicates almost same level in both operation modes.
4. CONCLUSIONS
Experimental investigation was conducted with low speed two-stroke marine diesel engine to know the characteristics of particulate emission. The following conclusions are obtained.
(1) The emission of particulate, SOF and ISF increase with an increase in engine load, and the high rate of SOF were indicated in any load.
(2) SOF concentration increases with an increase in cylinder oil feed rate or cooling water temperature. According to the analysis results of SOF components, cylinder lubrication has a significant effect on SOF emission.
(3) The effect of cetane index of the fuel is not clearly confirmed within the limits of this experiment.
(4) The particulate emission in the propeller load operation indicate a slightly higher value than that in the constant speed operation.
REFERENCES
1) Mollenhauer, K. et al., "Measurement of Particulate Emissions from Large Diesel Engines", ISME Yokohama 1995 Vol.1, pp.416-421, 1995-7.
2) Bastenhof, D., "Exhaust Gas Emission Measurements a Contribution to a Realistic Approach, 21st International Congress on Combustion Engine, D43, 1995-5.
3) Takasaki, K. et al., "Some measures to Control Exhaust Emissions from Stationary and Marine Diesel Engines", (in Japanese) , The 13th Internal Combustion Engine Symposium, Japan, pp.471-476, 1996-6.
4) Tsukamoto, T. et al., "Characteristics of Particulate Emission from Marine Diesel Engines", Bulletin of the MESJ, Vol.27, No.1, pp.1-5, 1999-2.
5) Tanabe, H. et. al., "Effect of Cooling Water Temperature on Particulate Emission from Diesel Engine", (in Japanese) Journal of The Marine Engineering Society of Japan, Vol.28, No.4, pp. 264-270, 1993-4
