Diesel engines are commonly employed for transportation and power generation. Injection of diesel into the cylinder plays a crucial role towards cycle efficiency and emission regulations. The literature overview of several parameters, such as swirl ratio, injection timing, exhaust gas recirculation, fuel temperature and combustion chamber geometry, is presented in this review work. It is suggested that Computational Fluid Dynamics (CFD) simulations inside the cylinder are useful for predicting the flow field, combustion and pollutant formation. Future directions are indicated for further research on direct injection diesel engines. © 2021 Engineers Australia.