DME/C 重油混合燃料を適用したディーゼルエンジン性能

Abstract

Diesel engines have been used as power sources of propulsion as well as electric generator for oceangoing vessels. Although they have advantages in thermal efficiency and durability compared to other types of internal combustion engines, their exhaust gases contain harmful substances, such as nitrogen oxide, sulfur oxide or particulate matter, which cause environmental pollution. Dimethyl Ether (DME) has been paid attention as one of the alternative fuels of the diesel engine, since it emits less soot emission compared to fossil fuels. Thus, various studies have been done that use neat DME as the fuel oil of diesel engines. The aim of this study is to clarify whether liquefied DME mixed with Bunker C (JIS C heavy oil) could improve the engine performance of diesel engines. In the present study, a pressure resistant fuel tank was made to mix liquefied DME and Bunker C, and a direct injection type of diesel engine was used to analyze the combustion characteristics. From the experiments, it is obtained that the ignition delay can be shortened with mixing DME to Bunker C. Also, DME mixed fuel can reduce the incomplete combustion substances, such as carbon monoxide, unburnt hydrocarbons and soot. Moreover, it can diminish the amount of carbon dioxide emission with DME mixed fuel while keeping almost the same thermal efficiency with neat Bunker C.