When developing new engines, it is always an important subject for designers to realize lightweight and compactness while ensuring required performance and reliability of engines. Factors which contribute to the lightweight and compactness of engines are considered to roughly be classified into two. One is a factor related to engine particulars and the other is a factor related to engine structure. Once the authors proposed a method of estimating engine weight using numerical formulas into which related principal particulars were incorporated to this society. This paper reported the results of analysis on the degree of contribution of the above-mentioned two factors by this method paying attention to actual data on the realization of the lightweight and compactness of two-stroke low-speed marine diesel engines which have been developed to date. These results of analysis are considered to become useful references for establishing the target values of lightweight and compactness when new engines are developed in future.
The simplified 2-color method is proposed which can estimate the distribution of the flame temperature and the soot density of whole flame by analyzing high-speed photographs. The factors influenced on its processing with the image analyzer for all pixels of flame were examined, for example the choice of two wave lengths, the simplified calibration method between luminous intensity of flame and true temperature, the kind of color films, the compensation of flame luminosity. The effectuality of this method was tested by the comparison of diesel flames with and without Ba2+additive. This simplified 2-color method can be used as a tool for the improvement of combustion process in DI diesel engine.
In order to find an effective method to discriminate the cavitation development stages, such as the subcavitating-, the transient- and the supercavitating stage, the cavitation noises and the cavitation aspects were measured in the internal flows through very small nozzles with various inlet shapes. It is shown that the noises in each stage are characterized by the peculiar behavior to able to discriminate the development stages.
In the first report, an attemp was done to develop an expert system with the knowledge base that describes the relations among many components in the system for the sequential control of a marine diesel engine plant.The system was proved to work well in such a complicated operation. In the present report the idea of the knowledge base with hierarchical structure is introduced. Then, the present knowledge base contains two different parts.The first is a kind of common knowledge base that describes the input-output relations of every component included usually in these systems and the hierarchical procedure is employed in the descriptions. The second is used for connecting the knowledge base of the components into a system, being based on the database that describes the component connections in the individual engine plant.Therefore the knowledge base can be easily built up for an individual plant by writing only the database of the component connections. It is finally pointed out that the new knowledge base system can be constructed at ease and work successfully.
In this paper, a new concept of the high frequency magnetohydrodynamic propulsion (HF MHD) which overcomes the problems for electrolysis of sea water and electrolytic corrosion in the electrode is proposed.The system construction and operation principle are illustrated.The switching characteristics of the resonant phenomenon are analyzed from the view point of switching stress of the switching devices.On the basis of the analysis, the HF MHD system is designed and effectively tested in the water tank.The new principle of HF MFD is supplemented with experimental results.
One of the author had published the paper of“On the Presumption of Bottom's Roughness with Making Use of Propeller Efficiency (Open) on CPP”. When calculating the increase of the bottom's roughness using the personal computer, it is important to give the good approximate performance curves between delivered horse power and ship speed.So, it was found that interpolation method with a cubic periodic spline gives good approximate values.If the spline function gained with the only four measured points can not give the good values, then, by adding two estimated points on the range of low and high ship speed, good performance curves could be gained effectively. Based on the accurate approximation of the performance curves, the increase of the bottom's roughness can easily obtained on the stand-by condition for short time by a personal computer.