Application of Emulsified Fuel Without Additives to DI Diesel Combustion

The purpose of this study is to reveal the effect of use of W/O emulsified fuel without additives on DI diesel combustion. The combustion pattern, which means the ratio of fuel mass burned in the premixed (or the diffusion) combustion period to the overall supplied fuel mass, is varied by changing the injection timing and the intake manifold pressure. The exhaust emissions, such as particulates, NO_x and CO, are measured. By analyzing the indicator diagrams, ignition lags are also measured. Contrary to the results of the other studies, NO_x is hardly reduced by using the emulsified fuel, although it does not increase. While the particulate emission is considerably affected, remarkable changes in S.F.C. and the exhaust gas temperature are not recognized. With decreasing the fuel mass fraction burned in the prernixed combustion (spontaneous ignition) or the intake manifold pressure, the effect of the emulsification on particulate emission turns from the promotion to the suppression. The possible mechanism of these effects of the emulsification is presented considering several results obtained in the previous basic studies.