There is a report that the ratio of the cost of the lubricating oil to the total maintenance cost of low-speed diesel engines reaches about 4:5. It is not desirable for the supply of the cylinder oil to increase, since the engines are of high performance type (fuel consumption saving engines). This raises a serious problem for the lubricating oil makers in maintaining the high performance while suppressing the rise in cost.
There is a report2), on the possibility of diagnosing the lubricating condition of the piston ring and the cylinder liner by analyzing the cylinder drain oil using a ferrography method.
9.2.3 Lubricating Oils for Trunk Engines
There is a report that the ratio of the cost of the lubricating oil to the total maintenance cost is about 2:5 for medium-speed diesel engines. The current suggestion is to fit a frame ring to reduce the consumption of the lubricating oil in recent medium-speed diesel engines. Reduction of the supply of the lubricating oil however, expedites the degradation of the lubricating oil. Thus, unless the lubricating oil used is suitable for the more severe operating conditions, the overhaul period is shortened, and hence, although the oil consumption is reduced, more frequent changes are necessary and no cost saving are achieved. There is a report3) that the estimation of the service life of a lubricating oil can be calculated using the index of "severity of the lubricating oil". This method for estimating the service life has been effectively used for the maintenance of the engines.
The demand for medium to high speed engines with high output which are mounted on high-speed ferries has increased recently. The characteristics of the operation pattern of these engines include an increase in output over a short period, the maintenance of a high-load condition during navigation, and sudden stopping of the engines. Such an operation pattern is severe for the lubricating oil, and hence a lubricating oil of high performance is necessary.1)
References:
1) THE MOTORSHIP Vol.80 No.946 (1999) 27-33
2) Hashimoto. Baba and Aoki, Journal of the Marine Engineering Society in Japan Vol.34 No.10 (1999) p.689-692
3) Hengeveld, Cannon and Scheele, Journal of the Marine Engineering Society in Japan Vol.34 No.5 (1999) p.340-348
[Norihiko KAGIWATA]
10. Nuclear Ships
10.1 Research and Development by Japan Atomic Energy Research Institute (JAERI)1)
10.1.1 Nuclear-powered Ship Mutsu
The nuclear-powered ship Mutsu completed its planned experiments in 1995 and was then overhauled in the Sekinehama mooring port, in accordance with the Basic Plan for Studies Necessary for Research and Development of Nuclear Ships by JAERI, approved by the prime minister and the minister of transport on 31 March 1985. After the overhaul, the Mutsu's hull was reborn as the world's largest oceanographic observation ship, the Mirai, under the Japan Marine Science and Technology Center (JAMSTEC). Sekinehama, the port used for the Mutsu, is also the home port of the Mirai. A maintenance station to service the oceanographic observation buoys to be mounted on board the Mirai and a building for processing and analysis of observation data was constructed there.
10.1.2 Studies for Improvement of Marine Reactors
Together with research and development using the Mutsu, JAERI has performed advanced research and development for improved marine reactors, aimed at realization of future marine reactors.
Marine reactor requirements for output, load conditions, and automated operation differ depending on the kind on ship on which the reactor is to be used. Research and development has been performed for two kinds of improved marine reactors: a large marine reactor, designated Marine Reactor X (MRX), and a deep-sea reactor, designated Deep-sea Reactor X (DRX). These reactors are intended for installation onboard an ice-breaking observation ship and a deep-sea scientific research ship, respectively, which are both expected to be constructed soon. Conceptual designs have already been established for MRX and DRX, and development have been proceeding in parallel for element technology, such as fundamental testing of passive safety technology, and element equipment, such as a control rod drive device to be built into the reactor containment. In parallel with design studies, it is necessary to solve technical problems related to practical application. Efforts in that direction have included development of a control rod drive device to be built into the reactor containment, basic studies of passive safety technology, a study of water immersion technology for marine reactors, development of integral reactor components. a study of sophisticated shielding design technology, development of a sophisticated automation system for the marine reactor plant, and development of a high-burnup core.
