With the increasing requirements for the less harmful exhaust emissions and better fuel economy, the conventional injectors in gasoline engines can be replaced by the Air Shrouded Injectors(ASI) in order to provide improved fuel combustion in engine operations. To find out the optimum ASI adapter attached to the conventional injector nozzle, the critical design parameters such as droplet size, fuel and air inlet angles, and injection angles are investigated on the basis of numerical simulations. To explain the characteristics of fuel atomization, these numerical simulations are carried out using the STAR-CD. The solution of injected air-fuel mixture is obtained by solving Lagrangian differential equations such as mass and momentum conservation. To reduce the number of numerical simulations required to investigate the characteristics of fuel atomization, Taguchi methods are used. The performance of fuel atomization is checked by the Sauter Mean Diameter (SMD) measured at the predetermined locations outside the ASI adaptor. The simulation results are compared with the experimental ones for the evaluation of numerical analysis. The suggested design technique in this paper has proved to be a useful tool in the early design stage.