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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.

Homogeneous charge compression ignition (HCCI) is a new combustion concept which achieves high efficiency, low nitrogen oxides (NOx), and particulates matter (PM) emissions. In order to realize the HCCI combustion, a homogenous mixture preparation plays an important role in the HCCI engine. However, it is well known that diesel fuel is very difficult to achieve a uniform mixture distribution within the engine cylinder because of its high viscosity and poor fuel vaporization. In order to eliminate these problems, the low viscosity and high volatility Dimethyl ether (DME) was added into diesel fuel to enhance the spray and atomization. The spray tip penetration and spray cone angle of DME/diesel-blended fuel has been examined by using direct photography technology. Measurements were achieved by using spray images taken with a high-resolution CCD camera synchronized with strobe light.

In recent years, entirely combined CFD-Multi-Zone chemistry combustion models have been developed fashionably in investigating the HCCI engine combustion. In this work, an enhanced Multi-zone chemistry model is recommended for the HCCI engine combustion and emission simulation. There are four sorts of zones enclosing the crevice zone; boundary layer zone, external zones and center zone of the engine cylinder have been applied. The volume of each zone is steady and depends on the engine geometry. The boundary layer zone is the closest zone to the engine cylinder wall. In this study, the reduced chemical kinetic oxidation mechanism of diesel/biodiesel-ethanol has been numerically investigated in homogenous charge compression ignition (HCCI) engine. The oxidation mechanism of the diesel oil-biodiesel-ethanol at different blends was developed and coupled with Multi-Zone chemical kinetics model.