Nowadays not only small, high speed diesel engines for automobiles, but also larger sized, medium and low speed engines for locomotives, generators and ships will be under some exhaust emissions restrictions. However, not much emissions research work on larger engines has been performed to establish whether measures used for reducing emissions of smaller engines are also effective on larger ones. This present paper covers emission data from four diesel engines having a bore of 110, 200, 320 and 450mm. The influence of (1) the size or speed of engine, (2) the fuel (gas oil or bunker fuel oil) and (3) means used to reduce NOx emissions such as “fuel injection timing retard ”and“exhaust gas re-circulation” are discussed. One reason for higher particulate emissions from bunker fuel oil is clarified using the visualization of burning spray in a model combustion chamber.
Fuel cells have worldwide impact as a new means of highly efficient and clean power generation, and they also have the possibility of application to the transports. We have researched on some problems of the solid oxide fuel cell (SOFC) applied to the power generation source for the ship in the future. The aim of this study is to make clear the influence of airborne-salt on the cell performance. The experiment was carried out with a small scale planner type SOFC in which the working air was accompanied with salted mist. As a result, a cell performance was not inferior to that in the case without salt, and rather showed some increasing tendency than that. It was also found that the inlet airborne-salt penetrated into the air-electrode but not into the electrolyte. In order to find out the cause for improvement in the cell performance, the behavior of the salt into the air-electrode was investigated and discussed.
To adapt SOFC system for marine power, the improvement of electric power generation performance and its quick response to large road change of the cell elementare required. The purpose of this study is to establish new manufacturing method of the cell element for the improvement of cell performances, and to verify its availability. In the experiment, test cells were prepared using electrolyte membrane with various size of roughness on the surface. The electric performances were measured and compared with each other by using hydrogen as fuel. Effect of interfacial structures between electrolyte membrane and electrode layers on the electric performances was investigated. The main results are as follows: the electric performances of the test cell were improved by the new manufacturing method. It was possible to reduce operating temperature of the cell, which contributes to get higher reliability of the SOFC system. The facts mainly caused by 3dimensional extension of real contact area and electrochemical reaction sites between electrolyte and electrodes. To investigate adaptability of natural gas as fuel for the SOFC system, reforming reaction and electric performance were also examined using methane as fuel. It was certified that the steady power generation with methane could be obtained.