Abstract: In this study, the Computational Fluid Dynamics (CFD) simulation to investigate the effect of piston crown to the fluid flow field inside the combustion chamber of a four-stroke direct injection automotive engine under the motoring condition is presented. The analysis is focussed on the study of the effect of the piston shape to the fluid flow characteristics. The fluid flow dynamics plays an important role for air-fuel mixture preparation to obtain the better engine combustion, performance and efficiency in the appearance of swirl and tumble flows. These two parameters represents the fluid flow behaviours occurred inside combustion chamber which influences the air streams to the cylinder during intake stroke and enhances greatly the mixing of air and fuel to give a better mixing during compression stroke. The numerical calculations were performed in a single cylinder of 1.6 L of a 4-stroke direct injection engine running at wide open throttle condition by using the CFD code. Two different piston bowls for considered engine speeds of 2000 rpm were considered to be compared to evaluate swirl and tumble flows produced during intake and compression stroke. The results obtained from the numerical analysis can be employed to examine the homogeneity of air-fuel mixture structure for better combustion process and engine performance.