Not only the torsional vibration but also the axial vibration in the crankshaftings of the long stroke, large size, low speed diesel engines become more and more excessive, nowadays.
So this paper refers to the 3 dimensional analysis of the forced vibration in the crankshaftings of the abovemensioned diesel engines by adopting the transfer matrix method. In this vibration model the crankshaftings is virtually divided into many elements and the transfer matrices are determined for each element, which is defined as mass-elasticity system.
The calculated values are compared with the experimental data in the five kinds of marine, long stroke, low speed diesel engines. As the results of the comparison, the calculated values approximately agreed with the experimental data. It has been assured that this present method can analyse the forced vibrations of the long stroke, large size, low speed diesel engines.

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The key to designing quieter engines lies in understanding the response of the main engine structure to the forces imposed during the engine cycle. Detailed analysis of the noise and vibration characteristics of the engine crank case yields important information on the significance of structural features for engine noise reduction. This paper presents the theoretical methods to determine the vibratory and acoustic characteristics of the crank case. A finite element model of the crank case, that employs the plate and beam elements, is adopted to determine the dynamic characteristics such as natural frequency, mode shape and modal mass. Using the dynamic characteristics obtained by FEM, frequency response functions from excitation point to the surface of noise radiation of the engine block are calculated by use of the modal analysis technique with measured modal damping. And a theoretical procedure using Boundary Element Method is developed to obtain the noise radiation property of the crank case. These methods above mentioned are applied to the crank case of an actual diesel engine. The calculated results of vibratory characteristics, space averaged square mobilities over the surface of noise radiation, acoustic intensities and acoustic radiation efficiencies are agreed well with the measured data. These techniques would enable us to investigate a low noise structural design of the engine block.

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An engine combustion analyzing system is an indispensable device when a test is carried out to develop a new engine or to improve the performance of existing engines, so increasing and developing are requirements to the analyzing functions from engineers and researchers.
To meet these requirements, the device is necessarily constituted based on the architecture having the flexibility and the extensibility, and the analyzing functions are always to be up to date.
This paper describes the constitution and the functions of the engine combustion analyzing system by the personal computer, also shown are the filter which is newly applied on the high-speed signal in the domain of the frequency using Fast Fourier Transform, and its effects on the combustion analyzed results.

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The quick response characteristics and good controllability of a 7-phase compound type D.C. commutatorless motor (abbreviated as 7-phase compound TBM) are comparable, in principal, to those of ordinary D.C. compound motor. Its operation modes can be accompalished by phase control through the use of 3-phase and 7-phase thyristor rectifiers.
This report summarizes both the design for the compound excitation circuit and the experimental results of the 7-phase compound TBM. When the motor with usual separate or shunt excitation is started or impressed by a large load, the circuit generally yields a large rush current. So that the motor needs the large capacity of a power source. Contrary to this, the 7-phase compound TBM generates a large starting torque and small rush current since the motor speed goes down for a suddenly impress load. Therfore the capacity of a power source of the 7-phase compound TBM can be small.
This report shows that (i) the characteristics of the compound excitation can be changed by the turn ratio of a current transformer, (ii) the margin angle of commutation of the 7-phase compound TBM is larger than that of the shunt TBM, and (iii) the 7-phase compound TBM fits for the various machines with the wide speed varying load, such as winches and electric propulsion systems.

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The training ship “Fukae Maru” is fitted many electoronic control systems. This paper especially introduces the electrohydraulic systems of her main engine among them. These are the speed control system, the automatic load control system and the active vibration isolating system.
And also this paper introduces electrical troubles and improvement of software after entering service in Oct., 1987. They are numbered in 26 matters for about one year. The half of them are remarkably caused by mistake of handiwork and programing (or debugging) than the damage of hardware.
It is important to increase the reliability of personal action for increasing that of marine electronics.

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