Investigation of 3D simulation of fuel injection timing and swirl ratio on mixture uniformity index, combustion, and emissions of diesel engine

One of the methods to improve the performance of diesel engine is the upgrade in the injection features and adopting some schemes in order to create a more homogenous and uniform mixture of the sprayed fuel with accessible air within combustion chamber. As to form a desirable condition conducive to stoichiometric mixture, factors such as the injection timing and air swirl ratio in combination were analyzed in this project and the optimum solution leading to maximum combustion and minimum emissions were introduced. The obtained numerical results by AVL FIRE for the base case have been compared with experimental ones showing a good agreement and indicative of reliability to modeling procedure. According to obtained results, the advanced injection mode of 712 CA results in greater uniformity index and the effect of swirl ratio is more sensible on ERUI at advanced injections rather than retarded injections. From the pollutant emissions aspect, the late injection policies are recommended since it is capable of simultaneous reduction of soot and NOx. In general, the compound cases of 712 CA- 1200 1/min and 723 CA- 1500 1/min are ideal for combustion and emission control strategies, respectively. The results can be programmed for electronic injection regulation through ECU system of engines while an appropriate swirl amount applied to achieve the results of interest.