5.6.3 Others
The pistons of No.2 and 5 cylinders were drawn, and various parts were measured; however, no dimensional changes such as abnormal abrasion of each equipment could be confirmed.
5.7 Properties of lubricating oil
During the test period, the properties were analyzed three times. As shown in Table 3, no remarkable changes attributable to the use of the emulsified fuel were found, and the lubricating oil was not affected thereby .
6. Conclusion
The following points were clarified through the above-described examination.
(1) In this test, the operation in the emulsified fuel mode was achieved without any special modification of the diesel engine, and the reducing effect of the NOx concentration measured in the beginning and in the end of the full running operation for 2,000 hours plus was continued, and it is confirmed that each parts of the diesel engine is fully withstandable. However, some signs were partly foreseen, which seem leading to a possible serious accident such as erosion of the piston if the continuous operation for longer time is achieved, and thus, it is necessary in future to change the material for the parts, and the shape of the fuel injection valve and the piston and the design of the structure of the combustion chamber.
1] Judging from the deposition of the glassy white substance on the piston head of all cylinders and the discovery of the erosion-like traces on a part of the pistons, it seems that the leaked oil from the fuel injection valve reaches the piston head directly, and overheated. It is necessary to take into consideration this point in developing the engine using the emulsified fuel.
2] Little combustion product was deposited in the combustion chamber and the exhaust gas system (including the turbine). This is considered to be partly attributable to the operational condition that the load is at least 50%.
3] Corrosion of the fuel oil system was slightly shown in the running part of the fuel pump as generation of damages, and in the fuel injection valve. The degree of corrosion was small, and it is considered that the effect of the additive having the lubricating effect was ensured.
4] When the emulsified fuel is used in the diesel engine for the electric generator, it is desired that the capacity of the fuel pump be determined taking into consideration the quantity of water to be added, and the capacity be sufficiently affordable.
5] It is desired to change the system to shorten the time required in replacement of the A-oil in the fuel oil piping when the operation of the emulsified fuel is completed.
6] It is desired to use distilled water in order to prevent deposition of the elements contained in the water fed to the exhaust system.
(2) Regarding the treatment of the leaked emulsified fuel onboard ships, the simplest and safest method of waste incineration system was adopted this time; however, there is a possibility leading to the marine pollution, etc. if the heating treatment system is adopted, and it is necessary to provide the facility to burn the leaked emulsified fuel directly in the boiler in a separate manner from the other leaked oils. If possible, it is desired to develop a safe, inexpensive and labor-saving system.
(3) It was confirmed that the emulsified fuel manufacturing device used in this test is sufficiently withstandable for the continuous use during the test period as a result of the adjustment of each part though the device is placed in the onboard environment which is severer than the land-based device in oscillation, vibration, salt damage, high temperature, etc.
