舶用ディーゼル機関の熱効率向上に関する研究

概要

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The recent competition in reduction of specific fuel oil consumption (FOC) among the marine engine manufacturers has realized engines whose FOC is as low as on the order of 120 g/ (PS⋅h) {163 g/ (kW⋅h) }, and a further improvement is still under way. Under these circumstances it will be valuable to estimate the limit of FOC reduction, and in view of this, the diesel engine thermal efficiency is thermodynamically analyzed by computer simulation of the performance and thermal load. The effects of the mean effective pressure, maximum combustion pressure, scavenging air pressure, degree of explosion (or compression ratio) as factors influencing the theoretical thermal efficiency, and those of turbocharger efficiency and longer stroke on FOC are examined. The effects of the combustion period, opening speed of the exhaust valve, nonsymmetrical scavenging method, cooling and insulating conditions of combustion chamber as factors influencing the diagram factors on FOC are quantitatively clarified. The possible limit of thermal efficiency improvement for mean effective pressure on the engine alone is analyzed by the above examination results. In order to improve the overall thermal efficiency, the low air/fuel ratio cycle and such compound systems as power recovery from turbo-charger and that by Rankine cycle system are examined.
社団法人日本マリンエンジニアリング学会の論文