Soot Formation in the Combustion of Emulsified Fuels in a Marine Low Speed Diesel Engine

Abstract

The experimental results obtained from the effects of emulsified fuels, diesel oil and marine oil, on the soot formation and engine performances in the combustion of a marine low speed diesel engine are summarized as follows:
(1) The emulsified fuels have a remarkable effect on the reduction of sooting ratio. The more we add water to the fuels, the more sooting ratio in the exhaust gas decreases. The minimum point of sooting ratio is being in this relation.
(2) In the burning gases of emulsified fuels, the specific concentrations of carbon monoxide are more than in the original fuels. So it is suggested that the water in the emulsified fuels contributes on the water gas reaction.
(3) Single soot particle measured with electron micrograph is a sphere of about 140Å in diameter and sizes are nearly same in a soot of both fuels. The swarm of soot particles is smaller in proportion to add water in emulsified fuels.
(4) Ignition lags are longer in the burning of the emulsified fuels than in the original fuels, but the exhaust gas temperatures are lower. The consumptions per original fuels are little.
(5) In the using of emulsified fuels, there is most fitting injection timing for the reduction of soot weight, fuel consumption and exhaust gas temperature.
(6) Suction pressure has more influence in the using former fuels than latter fuels on the engine performance.
(7) The volume of carbon sticked on the surface of the combustion chamber is little.
From these experimental results, it is found that, in the burning of the emulsified fuels of a marine low speed diesel engine, there are remarkable effects on the reduction of sooting ratio, the consumption per original fuel and the dirt in combustion chamber. But there are problems of the corrosion of exhaust pipes and the dirt of lubricating oil by the water in emulsified fuels.