This experiment has studied the ignition delay of single emulsion droplet, under high pressure and high temperature. In the range of this test, the main results were as follows;
(1) The effects of added water on the ignition of emulsion droplet were different before and after the vaporizing of the water particles. When the water particles in emulsion droplet were vaporizing, the effects of latent heat and micro-explosion were considered.
(2) The ignition delay of emulsion droplet increased with the increase of water contents. The effect of the surfanctants was small.
(3) Reducing the diameter of emulsion droplet, the ignition delay became shorter.
(4) The rise of emulsion droplet temperature exhibited moderate with the water contents increasing. As the water particles in emulsion droplet were vaporizing, the temperature history showed an inflexion point.

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Developments of “electronic-hydraulic fuel injection system” and “electronic-hydraulic suction/exhaust valve system” are required to reduce fuel consumption and smoke by increasing injection pressure and velocity of the valves.
A laboratory system which combines the above two systems was built using numerical simulations. Then investigation was done in the both ways of simulations and experiments to analyze the relationships between specific fuel consumption and driving power for the laboratory system, which had not been clarified through the past study.
As the result, constraint conditions and adequate methods for the driving power to reduce fuel consumption became clear, and also both fuel consumption at the rated operation range and smoke at the all operation range were reduced.

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Torsional vibration of main propulsion shafting is one of the most important problems for the ship equipped with a long stroke diesel engine of small cylinder numbers.
In this paper, torsional vibration characteristics and its countermeasures for the shafting system equipped with 4 or 5 cylinder diesel engines are summerized.

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This research aims at establishing a new diagnostic system based on the acoustic sound for marine diesel engine in order to reinforce or substitute for the engineer's diagnosis.
This paper discusses to discriminate the different sounds caused by the different sizes of the cut on the exhaust valve of the two-stroke diesel engine. The acoustic sounds are transformed into the visible signals through various analyses.
The distinctive signals are found at the times of the combustion and the opening and closing the exhaust valve, while the power level at the former time becomes higher as the size of the cut on the exhaust valve is increased. The analytical system proposed here is, therefore, effective to diagnose the gas leakage from the exhaust valve of the diesel engine and can be developed into a more general diagnostic system in the future.

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