Numerical Simulation And Analysis Of Diesel's Combustion And Emission

With the increasingly shortage of petroleum resource and aggravation of environmental pollution, the development of Internal Combustion Engine is facing more and more severe challenge. All countries of the world have drawn up the increasingly strict emission regulations to limiting the pollution of the engine. The harmful compositions in the diesel engine mainly include the carbon monoxide (CO), the unburned hydrocarbons (HC), the oxides of nitrogen (NOx) and the particulate matters (PM). Due to a high air/fuel ratio in the diesel engine, CO and HC emissions are low, the main emissions are NOx and PM. Therefore, the popularization and application of diesel engine with reducing NOx and PM emission by effective measures will be of important theoretical significance and practical value to delay energy crisis and improves environmental problems.The 3-dimensional grid models including inlet valve and exhaust valve for the ZS195 type diesel engine are established by using Pro/E, HyperMesh and CFD. The combustion in cylinder is simulated.The fuel reformation and advanced injection are studied in this paper, and the fluid, temperature, fuel, NOx concentration and soot are analyzed.The simulation results show that, when mix-burning methanol with the diesel fuel, the in-cylinder temperature, NOx and soot are reduced, this is because that the methanol has a low heat value, a high vaporization latent heat, and a low cetane number. For advanced injection, the fuel has enough time to mix with the air, therefore increasing the homogeneity of fuel-air mixture, and reduce NOx and soot.