This paper deals with the investigation on the scavenging action of the captioned new type engine having no cylinder port, and the tests were carried out keeping pressure change in cylinder, piston movement and motion of scavenging and exhaust valves as similar as possible to their conditions during exhaust and scavenging period expected in actual engine.
Various shrouds were setted on the scavenging valve so as to enable that the main scavenging air through scavenging valve flows downwards almost along the cylinder wall of opposite side of exhaust valve, preventing the short circuit flow into exhaust valve from scavenging valve. Consequently, the scavenging air flow in cylinder was formed the U type flow which is effective to obtain a favorable scavenging action.
By changing the shape of shroud and the timing of exhaust valve closing, it was carried out such tests as that the gas flow patterns in cylinder during exhaust and scavenging period were observed through the transparent cylinder model with moving piston, and the scavenging efficiencies were measured using CO₂ gas instead of scavenging air for the model cylinder with gas tighted moving piston.
In order to know the effect of scavenging area, the tests of three valves system with two scavenging valves and single exhaust valve were carried out to compare to the cases of two valve system with single scavenging and exhaust valve.
As the results, the gas flow in cylinder and the scavenging performance for the newly proposed U type scavenging system were investigated and the useful suggestions to design these scavenging system were obtained.

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‘Electromagnetic Gears’ are going to be improved in order to realize ‘Ideal Ship Propulsion Systems’ in view of energy saving and labour reduction in navigation. The electromagnetic gears which were devised by me fifteen years ago were developed between 1972 and 1975. An equipment of the rating 16 000 ps 430/107.5 rpm made on an experimental basis was tested on various items such as a load test, a starting test and so on, in the development of the electromagnetic gear.
Any mechanical gears are not included in the original electromagnetic gears each of which is made of an electromagnetic coupling and a synchronous machine connected mechanically and electrically with each other. Each of improved electromagnetic gears described in this paper is made of an electromagnetic coupling, a rotating electric machine and a mechanical gear which are connected mechanically and electrically with each other.
We can obtain the following effects of improved electromagnetic gears.
(1) An electromagnetic gear can be inserted between a super-low speed propeller and a 2 cycle low speed diesel engine which is robust and reliable.
(2) Exhaust heat energy of a diesel engine can be utilized enough and certainly.
(3) Rotating speed and direction of a propeller can be controlled continuously by using an electromagnetic gear connected with 2 cycle diesel engine.
In this paper, the possibility of realization of ideal ship propulsion systems by using the improved electromagnetic gears are explained on the basis of the test results of the before-mentioned development of 16 000 ps electromagnetic gear and of an experimental equipment of a small capacity of wound rotor induction motor.

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The quantitative and qualitative analysis was performed to find how much cross current (called “load unbalance cross current”) was running in accordance with the unbalance rate of load share when two synchronous generators were in parallel running, how much bus voltage fluctuation and increasing rate of cross current (as troubled cross current) were caused if one generator offered defects in any modes to make external voltage abnormal.
As an example to apply the trouble characteristics in parallel running, the automatic parallelreleasing device for troubled generator is referred to protect the blackout of power source by finding out the troubled generator to be released out of the parallel. The device is recognized to operate satisfactorily when mounted on actual ship.

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The flexibility of machinery layout and control advantages of electric ship propulsion can be realized with the superconducting electrical machines, without the traditional space, weight and efficiency penalty of the conventional motor and generator.
This paper describes the features and problems of the superconducting electric propulsion system including the onboard refrigerating system, and that the use of the superconducting electric propulsion system offers significant application's advantages to future high performance vessels and ice breaking type vessels.
In order to evaluate the application's advantages, the study of the application of the superconducting electric propulsion system is carried out for ice breaking type LNG carrier, which shows that reduction in the required propulsion machinery space and weight permits a 65% reduction in the propulsion machinery space and a 70% reduction in the propulsion machinery weight with no reduction in the installed power, in comparison with the application of the conventional electric propulsion system.
And, the present status of R&D of the superconducting electric propulsion system, in U.S. and U.K., is reviewed.

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