The Weibull distribution has been widely utilized and played an important role in the failure data analysis. But, this model has some troubles such as a lot of calculations, difficulties of analyzing reliability and so on. In order to avoid these troubles, we propose a new failure model which is composed of exponential distributions. First, after introducing the new failure model, we determine the relations of the parameters of the Weibull model and the new model under conditions that these models have same mean value and same variance. Next, from these results, the transform-chart for transforming from the Weibull model to the new failure model is given, and the graphical method is shown by using the actual mechanical data. More, the usefulness of this new failure model is illustrated by examples from various reliability points of view.
In recent years, research and development in the field of ship automation and labor-saving have progressed in countries all over the world, and some practical systems have already been developed. But the diagnosis of the condition of diesel engines is very difficult on account of their complex mechanisms, and many of the practical systems for diesel engines are monitoring systems, such as“DATA LOGGER”. With existing engine condition monitoring systems, it is very difficult to monitor the cylinder pressure of a diesel engine continuously. The method of monitoring the cylinder pressure still largely depends on the ability of skilled engine operators to judge the problems in the components around the combustion chamber. In view of this, we have studied the application of the multivariate analysis method to the diagnosis of the components around the combustion chamber by using various characteristics derived from the cylinder pressure. The current engine condition and each failure can be expressed by vectors having several characteristics. It follows naturally that the engine failure can be discriminated by calculating the statistical distances between the vectors of the current engine condition and the vectors of each failure, and then by selecting the engine condition vector which is most similar to the failure vector.
Thyristor brush machine (TBM) is established as equivalent do machine without brushes and commutators. Since TBM is composed of polyphase drum type armature winding on the stator and polyphase thyristor bridge circuit, three phase ac voltage can be obtained at the same time with do voltage. In this paper, the characteristics of do or ac loading of TBM are investigated respectively and that of ac and do combined loading are discussed. Ac voltage of TBM can be stabilized by field excitation control, i.e., it is known as automatic voltage regulator, and do voltage, by gate control of thyristors. Power outputs on ac-dc parallel loading can be extended about 1.2 times as rated value as ac or do individual loading as for effective value of current of armature windings. It can be seen that the fundamental construction of TBM is much the suitable machine for marine use for small electrical noise, uniform torque generated and antiexplosion.
Here, we report the results of experiments following the previous report and premixed N2 gas in the fuel, in order to make basic explications about combustion method as the mixture of oil-water and recirculation method of the exhaust gas to reduce the pollutant. To sum up the results of our experiments, the most important points are as follows: (1) For cases in which there are both density difference between main stream and jet, the Reynolds number of nozzle fluid is steadily increased, the diffusion characteristics become a good results. But, at high flow velocities, flame is‘anchored’at some position downstream from the nozzle tip, this is turn adversely affects flame stabilization very close to the burner rim. These problems are experimentally solved that combustion gas is partially recirculated and combustion air is preheated. (2) With decrease of CO the concentration of CO2 and H2O in the flame increases when the fraction of premixed N2 gas in the C3H8 increase, thereby allowing the non-luminous flame phenomenon. CO concentration can be widely reduced by the method described above.
In the marine power generating system, it is very important to keep the continuity of the electric power having constant voltage and constant frequency characteristics. Particularly, in an automated ship, the reliability of the electric power plant is strongly required to be high. Therefore, at the design of the electric power system the following items should be considered as the bases. (1) Service electric power should be stable. (2) System is to be simple as possible. (3) Functional matching between electric power system and loads motors is to be done. In this paper, the rational planning and features about parallel running system and starting control system of motors are mainly described. Furthermore, the applied example to a tag boat is shown in detail.
We had done preliminary investigation to develop an exhaust silencer to be in used in small diesel engine (20-150 PS) . A requirement of the program was to subject the noise attenuation, endurance property, silencer volume, and pressure loss. This paper describes the construction, performance, and details of test results of silencer for small diesel application.
It is widely known that the fluidics has high reliability and no movable parts. So the authors conducted an experiment where the flow diverting fluidics valve was applied to a temperature control system. According to the results of the experiment, the following was made clear. (1) Where the flow diverting fluidics valve is applied to a temperature control system, the DTRC (Diverting Time Ratio Control - a sort of on-off control) is an advantageous method. (2) This method holds the temperature overshoot within the allowable range.