Diesel buses of public transportation in the main cities of Colombia are formed by turbocharger engines, such machines could operate in dual Diesel-NG way using the gaseous fuel as main energy source and the liquid fuel to pilot ignition of the air-NG mixture previously formed. This research is centered on the studies about formation process of the mixture in the intake system in a turbocharger dual engine. In this study the transport equations are established, it is associated to the fluids which enter to the intake engine during a period of engine operation. This model is simulated by means of CFD tools, using an electronic injector to provide natural gas. Also it is considered the fluidynamic behavior of mixture. Finally an experimental design applied to the simulations is made with the goal of optimize operational conditions of the injector that allow to get the most homogeneous mixture on the inlet runner to one of the cylinders engine. This mixture was obtained injecting natural gas at a pressure of 10 bars and placing the injector as close to the intake manifold.