Analysis of DME homogeneous charge compression ignition combustion

The characteristics of auto-ignition of DME/Air mixture in Homogeneous Charge Compression Ignition (HCCI) engine were investigated by numerical calculation with elementary reactions and experiment. Calculations were carried out using Di-Methyl Ether (DME) elementary reactions at 0 dimension and adiabatic condition. DME is paid attention as the alternative fuel of next generation because of its possibility to take the place of conventional fossil fuels. DME has good characteristics of auto-ignition and combustion with low flame temperature, and makes no soot because of its molecular structure. In autoignition process, DME shows two-stage combustion, heat release with low temperature reaction (LTR) and high temperature reaction (HTR). This characteristic is similar to higher hydrocarbons such as gasoline in auto-ignition process. In this study, analysis of HCCI combustion of DME/Air mixture was carried out by using numerical calculation and comparing with experimental results. In calculation, the CHEMKIN II, SENKIN and Curran's DME elementary reaction scheme were used. It was assumed that the temperature, pressure and composition of the mixture are always spatially uniform and the mixture is adiabatic. The calculation was carried out with changing equivalence ratio and initial temperature. Low temperature reaction and high temperature reaction mechanisms are investigated. Necessary factor for high combustion efficiency and low emissions are also investigated.