Permanent-magnet generators can be very efficient, do not require excition. However, the voltage regulation of Permanent-magnet generators became large in their over load conditions, because the magnet field cannot be controlled. It is preferable that the voltage regulation factor of generators has a small numerical value. In this paper, I discuss the voltage regulation of IPM (Interior Permanent-Magnet) generator.The IPM generator has two-layers of the permanent-magnet embedded in the rotor. The voltage regulation performances of the IPM generator are calculated using extended to cover the effect of various parameters on the voltage regulation performances. Experimental results of the IPM generators which confirm the analyses are also given. In this experimental result, the voltage regulation factor is 1.5% at the resistive load.

抄録全体を表示

Sufficient attention to fuel oil systems, which is one of primary factors to revitalize marine transportation, is a great importance. Today's fuel oil used aboard sea-going vessels is low-grade heavy fuel oil (densit-1.0g/cm³@15°C, kinematic viscosity-500cSt@50°C) which requires complicated heating systems and excessive heating energy. This causes hard-working environment to engineer crew due to high temperature in engine room (approximately45-50°C) . Still more, because of high heating temperature (approximately80-100°C) some fine components of fuel likely degenerate, coke or is wasted.
This study proposes a new usage of heavy fuel oil without heating, by mixing heavy fuel oil with oil thermally processed from waste plastics (hereafter called Waste Plastic Disposal or WPD) . In previous papers, authors have presented the achievement of application of WPD-mixed DO and WPD-mixed A.Oil to diesel engines.
This paper reports the result of application of non-heated WPD-mixed HFO to diesel engines including the inspection of engine functions and exhaust gas characteristics.

抄録全体を表示

In recent years, the demand for reduction of noise emitted into the environment has strongly increased for preventing noise pollution. For example, the ships, which have high noise levels, are refused entry to ports at night. As the major contributor of emitted noise to the environment is exhaust noise, it is necessary to reduce the exhaust noise as much as possible.
Conventionally, such as passive silencer technique, a larger silencer is needed in order to achieve larger noise reduction. Therefore, because of the limitation of space, it was actually difficult to reduce the exhaust noise of the ship.
For reducing the exhaust noise as well as minimizing the occupied space, the active noise cancellation technique was applied to the exhaust noise silencer for a diesel engine. In order to reduce the exhaust noise efficiently, at first, the acoustic behavior in an exhaust pipe was calculated by the boundary element method. At first, for optimizing the length of pipes and the positions of microphones and speakers, the active exhaust noise cancellation system (AENC) could be applied to the main engine for marine use. Also, by applying acoustic resonance aggressively, the AENC with only one speaker system could be developed for auxiliary engine.
The Filtered-X LMS algorithm with a signal filter was used for adaptive control. Finally, by assembling a passive silencer for high frequency noise, the active exhaust noise silencer was developed. Then the exhaust noise was drastically reduced to less than 65dB (A) at lm from the outlet.

抄録全体を表示

There are two distinct types of maintenance action, namely preventive one and corrective one. Preventive maintenance is performed at regular time intervals and can contribute significantly towards the increase of reliability and availability. It must be scheduled carefully in order that the availability is maximized through optimizing regular interval. On the other hand, corrective maintenance is performed when the system fails, and so the occurrence of corrective maintenance action is a random. From these considerations, it is clear that time is the most important factor in maintainability, and therefore, we classify maintenance data into two groups, ie, scheduled maintenance data and unscheduled maintenance one. Next, based on these classified data, we propose the new availability model which modifies Policy II given by R. Barlow and L. Hunter. Finally, we show the usefulness of the new model proposed here by applying these theoretical results to real data of the marine propulsion system.

抄録全体を表示

It has generally been known that Carbon-Flower is phenomenon that scale adheres and deposits on the outskirts of fuel atomizer when heavy fuel oil is used.
This phenomenon is supposed to occur by the adherence, carbonization and gasification of unburned heavy fuel oil drops.
This phenomenon has been reported in the papers entitled “Carbon Sticking in the Diesel Engine”and“Fouling in Fluidized Bed Coal Combustion”. However, the phenomenon was not fully understood because of the insufficience of informations. The problem is that there are a lot of residual carbon and various metals in the heavy oil, and the behavior of spray flow is not clear as well as the temperature around the adhering and accumlating point is not obvious.
This study has used various measuring methods in order to grasp the formation and growth mechanism of Carbon-Flower generated in steady spray combustion at atmospheric pressure.

抄録全体を表示

Burning oil slicks drifting on the sea is one of the methods of removing oil polution of the sea. In such case, it is necessary to understand the risk of fire fighting for saving lives of firemen. So to study the mechanism of oil slick combustion is very important. In this report, the combustion characteristics of oil slick in a small open tank, such as the combustion time, the boilover behavior and so on, are investigated under several conditions, and it is clarified that the characteristics of the combustion are influenced significantly by the size of open tanks used in this experimentation.

抄録全体を表示

In this paper, we report about generation of reduction agent for deNOx equipment used diesel engine. Following tests have been carried out, so that fuel for NOx-agent is used availably. One is investigation of exhaust gas character, in case of fuel addition in the cylinder, and the other is NOx reduction performance test, used the small size deNOx equipment.
As result of experiments, following have been found.
(1) . Gaseous hydrocarbon, available NOx reduction is generated by fuel sub-injection.
(2) . Sub-injection timing is suitable near BDC, opened exhaust valve.
(3) . Reduction rate of deNOx equipment with fuel sub-injection is equivalent one with gaseous agent, and is about 40%.

抄録全体を表示