Experimental and Numerical Study on Auto-Ignition and Combustion of Homogeneous Charge Compression Ignition Fueled With Dimethyl Ether

Experimental study of the autoignition and combustion characteristics of homogeneous charge compression ignition (HCCI) was carried out on a modified diesel engine fuelled with Dimethyl ether (DME) fuel. Numerical simulations were also performed by using the detailed chemical kinetic mechanism of DME oxidation proposed by American Lawrence Livermore National Laboratory (LLNL). The experimental results indicate that HCCI combustion with DME fuel can be realized in diesel engine with a few modifications, and it has a two-stage heat release characteristics. The emissions of HCCI combustion with DME fuel can be characterized by free of smoke and near zero NOx. The simulation results suggest that the single-zone model can accurately predict the ignition timings, including the low temperature ignition and high temperature ignition. The variations of key species (such as H₂O₂, CH₂O, OH, HCO, CH, etc) with crank angle during fuel oxidation and the effects of engine operating parameters on HCCI combustion can also be analyzed by numerical simulation.