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The homogenization of fuel, air, and recycled burnt gases prior to ignition as well as detailed intake, spray, combustion and pollution formation processes of Homogeneous charge compression ignition (HCCI) engine with liquid Dimethyl ether (LDME) fuel are studied by coupling multi-dimensional computational fluid dynamic KIVA-3Vr2 code with detailed chemical kinetics. An extended hydrocarbon oxidation reaction mechanism including 81 species and 362 elementary reactions used for (HCCI) engine fueled with (LDME) fuel was constructed and studded at different engine conditions by using CHEMKIN software and then a validating reduced mechanism that can be used in a modeling strategy of 3D-CFD/chemistry coupling for engine simulation is introduced to meet the requirements of execution time acceptable to simulate the whole engine physicochemical process including intake, spray, compression and combustion process.

A zero-dimensional, thermodynamic model with detailed chemical kinetics and cylinder wall heat transfer correlations has been used to study the detailed oxidation mechanism of natural gas in homogeneous charge compression ignition (HCCI) engine. A short mechanism made up of 241 reversible elementary reactions among 47species has been assembled from a previously extended detailed mechanism. The mechanism was numerically investigated at different operating and geometry conditions of HCCI engine during the time period in which both intake and exhaust valves are closed. The study is performed to elucidate the mechanisms of extinction and combustion behaviors of natural gas fuel with the effect of hydrogen addition to overcome the control of autoignition timing over a wide range of speeds and loads, limiting the heat released rate at high load operation, and meeting emission standards.