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The use of pure ethanol or the prevailing of it in the mixture with gasoline in flex fuel engines, led to a necessity of an auxiliary system to the cold start and engine functioning. Ethanol chemical properties can be used to explain this necessity. Ethanol is been used in Brazil for more than 30 years and many researches give support to the cold start technologic evolution. The cold start system enables the gasoline introduction into the intake manifold of flex fuel engines, when vehicles are using pure ethanol or a mixture with more ethanol than gasoline. The researches challenge is to find a way to start an engine using ethanol without the use of the cold start system using gasoline. This works presents a numerical analysis of the flow and heat transfer in a cold start system, using computational fluid dynamics. An experimental test bench developed to study a start cold system heating air and ethanol.

The development of computational procedures has allowed increasing the range of virtual analysis of various engineering problems. The design of industrial products must meet requirements of durability, strength, reliability, security, and criteria of low cost and weight. These requirements are among the many reasons that enable technological advances; and such advances are needed to make possible to increasingly use software's capacity of simulating real operating conditions of components. This work has as main objective to achieve fatigue analysis of a connecting rod of an automotive internal combustion engine by using software based on finite element method. For this were used curves of loads and boundary conditions, obtained from experimental analysis of the component, so it may be possible a correlation between experimental and computational results.

The increasing number of flex fuel vehicles using pure or mainly ethanol when mixed with gasoline led to a necessity of an auxiliary cold start system. These systems are based on introducing gasoline during the engine's cold phase. The researches lead to find an alternative to avoid using gasoline at cold start systems. This works presents a numerical analysis of the flow and heat transfer in a cold start system, using computational fluid dynamics. A prototypal vehicle was used to validate the simulations. The tests were done at controlled ambient temperatures: 0°C for cold start measurements and 25°C at chassis dynamometer to run the FTP75 emission cycle. The numerical data were validated and the results showed the possibility to get a temperature high enough to assure fuel combustion with emissions benefits.