When engines are newly developed, making them light and compact, while ensuring necessary performance and reliability, appeals to both users and engine manufacturers and is a permanently important subject which is required of engine designers at every time. The authors analyzed factors which contributed to making two-stroke, low-speed marine diesel engines light and compact, taking the relation with engine output into consideration, and clarified that there were two kinds of factors, i.e. particular relating factors and structural improvement relating factors. In addition, the authors analyzed the levels of the influence of these factors concretely and quantitatively, picking up some developed engines as examples, and published the results of analyses by the journal of M.E.S.J. Following the above, the authors analyzed processes through which the compactification of principal dimensions of engines already developed by various engine manufacturers had been promoted at every development work and present levels to which the compactification of engines attained by using evaluation indexes the authors proposed. This paper is shown to designers as reference material for them when they newly develop engines in the future.
Concept of solar-hydrogen-methanol energy system for the transportation sector in Japan is outlined. In the system, methanol is produced with CO2 recycled and H2 produced by electrolysis with photovoltaic power. Concerning CO2 recovery from the exhaust gas of a 10, 000 kW diesel engine to be used in the methanol energy system, the effects of CO2 recovery parameters such as gas and liquid flow rates, liquid concentration, and stripping temperature on the engine performance and the attainable CO2 recovery ratio are analyzed on the basis of a mass transfer calculation model for a packed column with aqueous monoethanolamine solution. Heat rejected from the engine is used for CO2 recovery, but reduction in the engine output power is not avoidable, which is mainly caused by the shortage in power of turbocharger and the supplemental supercharging power. Both the maximum attainable CO2 recovery ratio and the reduction in the engine output power depend on the ratio of the stripping steam feed rate to the flow rate of the exhaust gas.
In order to find out a clue to the solution of torque slip problem in keyless propeller, this study investigates the effects of taper machining error and surface roughness on friction behavior of tapered contact. Pushing-up tests were conducted using model propeller boss (AIBC3) and shaft (SF440A) . The experiments revealed that the friction behavior especially grip coefficient is significantly affected by taper machining error compared to surface roughness. Accordingly it is proposed that propeller boss should be pushed up into shaft to the regired push-up distance excepting the zone of low grip coefficient.
This paper describes the results of the continuous low load combustion tests by burning the heavy fuel oil in order to confirm the reliability of the medium sized medium speed diesel engine with a 260mm bore. To investigate the effect of the engine load on the exhaust smoke and the soot contamination in the engine, the combustion tests are conducted on the variations of the continuous operation loads at 0.2MPa and 0.4MPa in BMEP. The results indicate that the engine contamination with the soot deposit increases as not only the engine load decreases, but also the operation duration increases.
Measuring and evaluating method for a vibration of the internal combustion engine is highly developed through measuring machine histories-such as from the mechanical type to the electric type with a piezoelectric element as a transducer, and to the more improved type with a built-in FFT which can be analyzed into a frequency level. However, it has not been reached enough level quickly to measure/evaluate at the site. We started to investigate in 1993 (H.5) how the vibration of a combustion diesel/gas engine with a φ 160mm to 300mm cylinder influenced on required accessories as a damage, and tried to develop a new vibration indicator for an actual operation use, which was introduced a measuring/evaluating method using the 'Vibration Severity Grade' that ISO was reviewing at that time. New vibration indicator were adopted to some factories for their outgoing inspections and got good results. Followings are the histories and results of it.
In the present situation, some points concerning marine diesel engines are being improved upon. But combustion and exhaust space, where dust and residue were generated by using poor quality marine fuel oil, are still trouble-some factors. And still, some causes of the engine trouble have not yet been made clear. In this investigation, we analyzed the combustion residue which was collected from overhauling the main engine and the generator engine on seven motor ships among those operated by Mitsui O.S.K. Lines. Then, we also investigated the formation of combustion residue.