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Flex-fuel Vehicles in Brazil

with Mario R. Duran


Brazil Flex-fuel badges

Clear external badging is used in all Brazilian flexible-fuel vehicles. Shown here is a sample of flex badging from several Brazilian automakers.

© Mario R. Duran
Thanks to Mario R. Duran, transportation planner currently working in Brazil, M.Sc., U.C. Berkeley and M.P.A., Harvard University, who graciously agreed to answer our questions regarding the use of ethanol as a fuel in Brazil. Here is the third and final of four questions; the first one shed light on the food vs. fuel debate as it relates to ethanol and the second on ethanol and fuel price fluctuations.

Scott & Christine: In America we have specifically manufactured flex-fuel vehicles that can use E85. Our regular gasoline vehicles are limited to E10. Are all cars manufactured for the Brazilian market able to burn straight E100 as well as blends?

Brazilian gasoline cars are optimized to run on the country’s mandatory gasoline blend, which varies between 20 to 25% of alcohol, as no longer is pure gasoline sold in Brazil. Since July 2007 the blend was set at E25, the maximum allowed by law. Though in theory Brazilian flex cars can run on any blend of gasoline and ethanol, the fact is that flex engines are optimized to burn any proportion of E25 gasoline and hydrous ethanol with up to 4.5% of water content (E100). American E10 and E85 blends, and the Brazilian mandatory E25 blend, all used anhydrous ethanol for the standard blend sold to the public. This means that typical Brazilian flex engines are capable of burning any mix of straight gasoline, anhydrous ethanol and hydrous ethanol, but not pure unleaded gasoline. Just two models, the Renault Clio and the Fiat Siena Tetrafuel are sold with a warranty from the manufacturer to run on pure unleaded gasoline too. This is important only for Brazilian travelers taking their flex vehicles to neighboring countries, such as Argentina and Uruguay, where only straight gasoline is sold. The capability of Brazilian vehicles to run on pure hydrous ethanol, just as the old ethanol-only vehicles did, is important, because here the production cost of hydrous ethanol is around 20% lower than anhydrous alcohol, and the latter type of ethanol is the only one used in the blend sold in the US and Europe for E85 flex fuel vehicles.

Other important feature of the Brazilian flex fuel vehicles is that even though temperatures during the winter are not as cold as in the Northern Hemisphere, they do drop below 15°C (59ºF), causing cold starting problems when using E100. The higher the ethanol content in a fuel blend the loss of evaporative pressure occurs earlier (for example, E85 will cause cold starting problems only at temperatures below 0°C/32ºF). Both the US and European countries use a regional E85 winter blend that reduces the ethanol content, to E70 in the US at regions where temperatures regularly fall below 0°C during the winter; and to E75 in Sweden, from November until March. Brazilian engineers solved this problem since the early ethanol-only vehicles by providing a small secondary gasoline tank located near the engine, thus injecting E25 gasoline when cold starting the engine at low temperatures. A new technology planned to be included in the next generation of flex engines scheduled for 2009 will allow eliminating the auxiliary gas tank, by heating any ethanol blend of ethanol stored in the main gasoline tank before injecting the fuel to the chamber during a cold start at low temperatures. This new feature might indeed open a possibility for E85 flexible-fuel fuel vehicles in colder countries to run on higher ethanol blends up to E100.

Scott & Christine: Do you have an opinion on whether or not the US should follow Brazil’s lead in the use of ethanol?

Any country considering to develop a bioethanol industry for use as fuel in a sustainable way should consider several variables, such as agricultural land available; how much of this land is going to be needed to produce biofuels to attend domestic demand and for how long; the expected yield per acre, and how much productivity and the energy balance could be increased by adopting technology from other countries; the expected cost of the final product as compared to gasoline; and by the Brazilian example, what public policies and subsidies or tax incentives are required to develop such industry.

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