Towards a more sustainable transport sector by numerically simulating fuel spray and pollutant formation in diesel engines

Diesel engines account for approximately 50% of new passenger-car sales in the European market and are the major contributor to pollutants that adversely affect human health and the environment. The most adverse pollutants emitted by the combustion of diesel fuel are NOx, soot, CO and HC. Numerous studies have been carried out to determine the influence of engine design, fuel injection, fuel-air mixing and combustion on pollutant emissions. Information gained through experimental research of in–cylinder processes is limited, and the body of knowledge can be improved by the use of numerical modelling and computer simulations. Computational Fluid Dynamics (CFD) has become a valuable tool that decreases the time and the cost of experimental research. Therefore, CFD is being increasingly used in development of combustion systems. This paper presents how the development of CFD models is the proper approach towards achieving a cleaner and more sustainable transportation sector. The physical models for the liquid fuel disintegration, evaporation and pollutant formation are used and implemented into the commercial CFD code FIRE. The models are capable of predicting complex in–cylinder processes and, ultimately, the formation of pollutant emissions. The results from numerical simulations, such as NOx and soot concentrations, in–cylinder pressure and temperature are found to be in good agreement with the existing experimental data.