Search Results

In Direct Injection (DI) diesel engines, combustion gets affected by change in in-cylinder air motion and Fuel injection system characteristics. Computational Fluid Dynamics (CFD) based models give detailed insight into the combustion phenomena. The present work investigates the effect of different combustion chamber geometries and fuel injection system parameters on engine emissions and performance aiming to improve trade-off between NOx and smoke. AVL FIRE CFD software is used in this work. Research engine having 9 liter capacity of heavy duty application has been selected for the study. Seven hole injector is used with mechanical fuel injection system having 1000 bar maximum pressure capability. Inputs required to model complex combustion process in the AVL FIRE are derived from one dimensional engine simulation software AVL BOOST.

With the upcoming stringent norms for diesel engines and continual pursuit for more and more fuel-efficient engines, it is necessary to enhance air-fuel mixing for proper combustion. The design of inlet port plays an important role in the engine performance, because the air-fuel mixing depends upon the air turbulence. Research showed that helical type inlet-port will be ideal for the engine with nominal injection pressure value less than 800-bar and thermodynamic simulation results highlighted the need of an optimum swirl number for the specimen engine. A parametric study on inlet port design has been done to achieve the optimum flow capacity.