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Along the last thirty years one of the challenges is to develop an engine working with ethanol with the same performance and characteristics of gasoline engines functioning at low temperatures. In Brazil the production expansion of flex fuel engines is the main motivation for technology development and research to improve the engine cold start and functioning, when using ethanol. The use of gasoline as an auxiliary in the cold start system is now the main characteristic of this system. In this work the performance of a new cold start system is analyzed. Tests were performed in a vehicle and the results show the potential of the new technology.

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.