The marine diesel engine using water emulsified fuel was operated in a diesel engine plant for the electric generator on Training Ship “Nippon Maru”. This practical operation was carried out 2, 063 hours of total running. However several problems such as the lack of response performance to rapid increase of electricload and difficulty in disposal of leaked emulsified fuel from fuel injection system, occured in this operation. Further more the influence of emulsified fuel to the constituent parts of diesel engine was investigated when it was overhauled and the followings were found: 1) On the case of using emulsified fuel, the opening pressure of injection valve lowered always in comparison with using marine diesel fuel. 2) Slight abnormal wear was observed at the fuel injection nozzle and pump plunger. 3) Glassy white deposit and wrinkled traces which were caused by the water contained in emulsified fuel were found on the piston herd.
The atmosphere over the Osaka bay area has been polluted severely for so many years that effective countermeasures against the air pollution have been requested as soon as possible. The discharge amount of NOx, SOx and CO2 from the ships in Osaka bay are estimated in order to know how largely the marine traffic contribute to those air pollutants discharge over the Osaka bay area. The estimation results show that, (1) the ships discharge the about 40% of NOx and SOx of total amount over the Osaka bay area, though the CO2 discharge is very small as 3%, (2) the spatial distributes intensively in the port zones and in the deep east-north region of Osaka bay mainly due to the discharge from tankers and general cargo ships staying there. The IMO/MEPC regulation, which is intending to control the air pollutants discharge of the engines installed on new ships since the year of 2000, cannot be expected so effective for the improvement of severely polluted region such as Osaka bay area. Other countermeasures such as the control of ship speed, cargo handling time, therefore, investigated here and suggests that systematic strategy could be effective when those measures are introduced together, with IMO regulation.
Many of the fishing vessels have the lubricating oil stored in the storage tank. The troubles will be caused if some water get mix with diesel-engine oil in the tank. So it is important for the diesel-engine oil to have the water resistance. We decided the test method for the water resistant characteristics of diesel-engine oil. The test method is as follows. Heat the bath liquid to 54°C. Add the sample of the oil under test to the test tube up to the 80mL. Place the test tube in the bath at 10 min. Add 0.4mL distilled water to the same test tube. Clamp the test tube under the stirring paddle. Lower the paddle into the test tube and stir for 30 min to a speed of 1500rpm. Pour the contents into the color comparison tube with tapered plug. Heat the bath liquid to 40°C. Place the color comparison tube in the bath for 4 weeks (672 hours) . Remove the color comparison tube and sample the test oil 5mL at 30mm under the surface of contents. Test the base number of the oil by JIS K 2501 (Petroleum products and lubricants - Determination of neutralization number) using potentiometric hydrochloric acid titration. Calculate the ratio of the base number after test to before test. 70% or above is passing.
HOKUTO MARU is one of the training ships belong to The Institute for Sea Training, installing one steam engine for propulsion and two main boilers. She carries out training voyage abroad once or twice a year in addition to her domestic voyage since her completion on June 16, 1976. The motor for Forced Draft Fan of No. 2 Main Boiler on her was burned out and rewinded in February and July 1996. During the investigation for the reason, the insurance resistance of the motor was decreased again and was rewinded two times. After all, the reasons were considered environment pollution, structual factor and etc. Afer the final repairment for this trouble, she has completed her training voyage smoothly.