Study on In-cylinder Purification Technology for Gasoline Engine Based on Chemical Reaction Kinetics

The increasingly stringent regulations on automobile exhaust emission make it more and more important to study and improve the in-cylinder purification technology for gasoline engine. In the process, it is the core technology that using the three-dimensional CFD coupled chemical reaction kinetic mechanism to analyze the combustion and initial emission in the engine cylinder. Furthermore, the key point of this method is to develop high accuracy chemical reaction mechanism. Based on the physical and chemical properties of domestic 92# gasoline, this paper built a new model of multi-component alternative fuel, and then constructed and optimized the combustion chemical reaction mechanism according to the composition of alternative fuel. The results showed that physical and chemical characteristics of the domestic 92# gasoline are consistent with those of the alternative fuel consisted of iso-octane, n-heptane, toluene, diisobutylene (DIB) and methyl tertiary butyl ether (MTBE) by the percentage of 26%, 20%, 37.5%, 10.5% and 6%. The combustion reaction mechanism for multi-component alternative fuel includes 135 species and 635 elementary reactions. It can accurately predict the ignition delay time and flame propagation speed, and also can calculate the in-cylinder pressure and temperature in combustion process. This reaction mechanism can be used for in-cylinder three-dimensional combustion and initial emission simulation.