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This study deals with the development of controlled-ignition technology for high performance compression ignition alcohol engines. The objective of this study is to make clear the main factors that govern the auto-ignition phenomenon of alcohol spray from the physical aspects. In the mixture formation process, two kinds of factors that govern the auto-ignition phenomenon of alcohol spray have to be considered. One can be called the "internal" factor and relates to fuel properties. The other can be called the "external" factor and corresponds to the surrounding gas conditions such as pressure, temperature and oxygen concentration. This paper focuses on the effect of oxygen content of entrained gas as one of the external factors affecting auto-ignition. Spray mixture formation process up to auto-ignition of ED (Ethanol-Diethyl ether) blended fuels in a large constant volume electrical heating chamber was visualized by shadowgraph method.

This study deals with the thermal efficiency improvement of diesel engines operated by W/O (water-in-oil) type emulsified fuels. This paper focuses on the feasibility of W/O emulsions as fuels applied to small diesel engines from the view point of compatibility between lower fuel consumption and lower NOx emission. Effects of water content ratio and mean diameter of water scattered in gas oil on ignition, combustion and emission characteristics in a small DI diesel engine with progress of fuel injection timing were experimentally investigated. Results showed that water content ratio strongly influenced on ignition delay and associated combustion characteristics after auto-ignition, and mean diameter of dispersed water in gas oil was not sensitive parameter on ignition and combustion.

This study deals with the development of compression ignition DI alcohol engine with higher efficiency and lower emissions comparing to the conventional internal combustion engines. In order to establish such high performance alcohol engines, development of controlled ignition technology is required. This paper focuses on the main factors that govern auto-ignition phenomenon of alcohol spray from the view point of fuel properties. The reason of poor auto-ignition quality of alcohol spray was theoretically and experimentally revealed. That is difficulty of simultaneous attainments of ignition-suitable concentration and temperature in a spray mixture formation due to their smaller stoichiometric air/fuel ratio and larger latent heat for evaporation in comparison with conventional diesel fuels.

This study deals with the development of compression ignition DI alcohol engine with higher efficiency and lower emissions comparing to the conventional internal combustion engines. The objective of this research is to make clear the spray mixture formation process of alcohol fuels utilizing high-speed visualization technique. The results show the difference between gas-oil and ethanol in their evaporation process. In case of ethanol spray evaporation was rapidly completed in comparison with gas-oil spray even though the latent heat of vaporization of ethanol is approximately five times larger than that of gas-oil.