TWO ZONES THERMODYNAMIC MODEL FOR HIGH SPEED MARINE DIESEL ENGINES

In this paper two-zone thermodynamic model has been used for modeling the combustion process in direct injection diesel engine based on the results of modeling the combustion process by using single zone thermodynamic method. Single zone thermodynamic method depends on the average value of in-cylinder temperature and pressure, which considered one of the main defects of using one-zone thermodynamic model. Hence, developing a new model is very necessary especially for better description of the in-cylinder peak temperature during the combustion process. The concept of two-zones thermodynamic model is based on dividing in-cylinder gases in two zones the first zone is unburned zone which contains fresh air and the injected fuel, and the second zone is burned zone which is formed from combustion products with high temperature. The importance of the two-zone thermodynamic model is using it to calculate and to model Nox emissions. The formation of Nox emissions highly depends on the in-cylinder peak temperature. Hence, the more accurate results in modeling the temperature of in-cylinder gases lead to obtain more accurate results in modeling Nox emissions