Experimental Study on Reduction of Exhaust Emission from Marine Two-strike Diesel Engine

以低速二冲程、十字头式排气涡轮增压船用柴油机（缸径370 mm、冲程880 mm、输出1105 kW、转速188 rpm、缸数3台）为试验对象，了解其颗粒排放特性，并对颗粒和NOx的减少进行了研究。利用x射线荧光光谱法对收集到的颗粒物质的过滤器进行分析，以检查颗粒的来源。在发动机上安装了新型润滑系统（高速进给式润滑器）。它可以通过电子控制在最佳时间精确地给油，与传统的机械式加油器相比，可以减少气缸润滑油的消耗。得到如下结果：(1)颗粒、可溶性有机组分和不溶性有机组分的排放随发动机负荷的增加而增加，且在任何负荷下均表现出较高的排放率。(2)颗粒排放随气缸供油量的增加而增加。根据软质成分分析结果，气缸润滑对软质排放有显著影响。(3)随着燃料含硫量的增加，软灰和干灰排放以及硫酸盐排放增加。颗粒物质中燃料硫转化为硫酸盐的速率几乎与燃料中硫含量无关，并且随着发动机负荷的增加而增加。(4)当发动机使用水乳化燃料时，NOx排放减少，但比油耗和PM排放增加

Experimental investigation was conducted with low speed two-stroke, cross-head type, exhaust turbocharged marine diesel engine (Bore: 370 mm, Stroke: 880 mm, Output: 1105 kW, Engine speed: 188 rpm, Number of cylinder: 3) to know the characteristics of particulate emission and to study particulate and NOx reduction. Filters on which particulate matter collected were analyzed using X-ray fluorescence spectroscopy to examine the origin of particulate. The new lubricating system (high speed feed type lubricator)was equipped on the engine. It enables a precise feed of cylinder oil at an optimum timing by electronic control and can reduce the consumption of cylinder lubricating oil compared with conventional mechanical type lubricator. The following results are obtained.(1) The emission of particulate, SOF (soluble organic fraction) and ISF (insoluble organic fraction) increase with an increase in engine load, and the high rate of SOF were indicated in any load.(2) Particulate emission increases with an increase in cylinder oil feed rate. According to the analysis results of SOF components, cylinder lubrication has a significant effect on SOF emission.(3) The SOF and dry soot emission, as well as sulfate emission, increase with an increase in the sulfur content of fuel. The conversion rate from fuel sulfur into sulfate in particulate matter is nearly independent of the sulfur content in the fuel and increases with an increase in the engine load.(4) When the engine is operated with water emulsified fuel, NOx emission is reduced but specific fuel consumption and PM emission increase