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It is known that aerodynamics influences directly on a vehicle´s fuel consumption, especially at speeds above 45-60km/h, where it becomes the main parasitic loss. With increasing pressure on automakers to develop more efficient vehicles, aerodynamics is playing a crucial role in the goal of saving vehicle´s fuel. Usually aerodynamic development starts in the early stages of the project, responsible engineer works together with designers and body/ergonomics engineers, using CFD simulations as tool. At certain point in the development time line, full scale or scaled models are manufactured and tested in wind tunnels, where vehicle gets a refinement on its external aerodynamics. However, the measurement of aerodynamic drag which is effectively used for homologated vehicle´s fuel consumption is done by coastdown testing. This paper shows a correlation between results from CFD simulations and results measured from wind tunnel and coastdown testing.

The vehicle windshield defogging performance has direct influence under driver safety. In extreme situations, when the vehicle is not equipped with air conditioner and loaded with maximum occupancy, the defroster system must correctly direct the flow in order to defog pre-defined regions on the windshield. This process can't take too long and must guarantee a minimum fog-free area to increase driver's visibility. The main objective of this paper is to demonstrate the defogging simulation methodology developed by FIAT Brazil and Multicorpos Engineering. It uses CFD simulations with StarCCM+ software. Experimental data obtained from climatic chamber is used to compare the numerical data and validate the methodology. The simulations were able to conclude that defogging performance is correlated to flow homogeneity and its mean velocity on the internal windshield area. CFD simulations were used to indicate fin angles that can enhance the fog layer removal.