Advances in diesel generating field in recent years have resulted in high turbocharged diesel engines and compact generators. However, it raised new problem, i. e. poor ability against load change which causes large speed deviation, compared to conventional electric power units. In order to design proper electric power units, the practical means for studying performance of diesel engines under transient conditions, are required.
In this paper, a mathematical model for four-stroke diesel engines coupled with generator developed to meet the above mentioned requirement and comparisons of calculations by means of a Hybrid computer with measurements on the test bed, are described. The mathematical model consists of engine, turbocharger, speed governor and generator, further, for the purpose of general application, all variables are converted into non-dimensional values divided by the valures at rated output. Reasonable agreement between calculations and measurements using a 480 kw turbocharged diesel generator is obtained, which proves the validity of the similation program. And using the simulation program, a comparison of the response ability between mechanical-hydraulic and electric-hydraulic governors is also described.

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The Measurement of the indicator diagrams is indispensable in the combustion analysis of internal combustion engines. However, it is exceedingly difficult to obtain accurate indicator diagrams, even today and in spite of the considerable advance and improvement of various precision instruments and analytical techniques. For example, a pass from the interior to the outside of the combustion chamber must be made for measuring the indicator diagrams. And likewise it is difficult to make a pass and attach a pick-up sensor to measure the cylinder pressure especially in engines available on the market.
The stresses of various parts of the engine were measured in order to estimate the cylinder pressure without making an actual pass and application of the sensors. As a result of running a comparison among all of the stresses, an apparent relationship was found especially between the actual cylinder pressure and the stresses of the cylinder head bolts. In this case, the correlation between clyinder pressure and the movement of the cylinder head could be explained mathematically by the differential equations of the cylinder head vibration system. And the constants in these equations could be deduced by the experimental measurements.
Thus, a factual indicator diagram could be estimated by means of adding the vibrational correction to the stress variations of the head bolts. Using this method, it was shown that indicator diagrams could be estimated precisely and accurately.
Moreover, the vibration behavior of the cylinder head can be also calculated in a reverse fashion from the indicator diagrams by this method. In addition, this method can be applied for the measurement of actual indicator diagrams, also may contribute to a better understanding of the noises emitted from the engine surface during operation.

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In a stern tube seal liner using high chromium stainless steel, sometimes troubles occur owing to pitting corrosion and abnormal abrasion. Therefore in order to develop the new stainless steel liner superior in corrosion, the effect of chemical composition was investigated by immersion corrosion tests in 3% FeCl₃ solution. From the results of above tests, best composition was selected, and the abrasion resistance of the selected material was confirmed by trial tests using 220 type seal liner. Consequently the followings were found;
1) Reducing the carbon content to 0.1% or less is effective to make corrosion resistance better.
2) The pitting corrosion resistance is improved by containing 1 to 2% molybdenium and special element.
3) On heat treatment, water cooled liner is better than air cooled one in view of decreasing corrosion rate.
4) The new developed stainless steel liner is confirmed to be superior to ordinary one in pitting corrosion resistance.

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