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In last few years, Petrobras has been working to make feasible the vehicular usage of the natural gas (NG) produced in Brazilian north region. This gas is produced in the Urucu field located at the Amazon forest. Due to its low methane and high nitrogen contents that could promote, respectively, performance losses and higher NOx emissions, Urucu's gas does not meet ANP specification for vehicular natural gas. Previous studies performed at Petrobras Research Center (CENPES) indicated the possibility of vehicular application for Urucu's NG, attending the Brazilian emission legislation (PROCONVE). However, with new PROCONVE's phases, recent vehicles have more advanced technological levels of fuel injection and catalyst systems, which require that kits for natural gas follow this evolution, including interfacing with flexible fuel engines.

Vehicles manufacturers, in search of cost reduction, fill the tanks of recently manufactured vehicles with the least volume of fuel necessary for future commercialization. The adoption of such practice, depending on the diesel fuel storage conditions, may lead to oxidation products formation in the fuel system and to problems during the first start of these vehicles. Some vehicles manufacturers, trying to minimize the occurrence of these problems, replace the diesel fuel in the vehicle tank with new fuel when vehicle storage time reaches 90 days. As a result of such occurrences, the opportunity for a first fill diesel fuel development, that presented better oxidation stability during storage, was identified. In the first stage of the special diesel fuel development, various analyses where conducted in laboratory, in the sense of defining criteria for the fuel formulation, taking into consideration the chemical variability of commercial Brazilian diesel fuel type A and biodiesel.

In Brazil, gasoline boats are mostly equipped with imported engines. These engines are not prepared to gasoline with high ethanol content. CENPES (PETROBRAS Research and Development Center) has large experience in automotive engines and vehicles testing for fuels development. However, gasoline marine engines need infrastructure, methodologies, and equipments different from those typically used in automotive testing. This work describes infrastructure and methodologies developed by CENPES to assess fuels performance in an outboard engine, running at water tank. It also studies the influence of gasoline formulations with different ethanol contents in this kind of engine performance. Additionally, it was performed an endurance test using a gasoline formulation with 10%vol. ethanol.

The increasing ethanol participation in Brazilian fuel market and its supply and price oscillations, motivate studies on multifuel engines behavior with the two specified types of ethanol in Brazil, the anhydrous and the hydrous fuels. The present work includes a comparative engine test bed performance study of a multi-fuel engine equipped with a programmable electronic central unit (ECU), fueled with anhydrous and hydrous ethanol. Fuel properties, engine performance, emissions and combustion parameters are reported using these two fuels for maximum power operating point. The programmable ECU was installed in order to make possible the setting of some parameters that are not accessible in engines operating with commercial ECU. This way, torque was optimized regarding spark timing and air fuel ratio, for all selected fuels and engine conditions tested. Test results presented the effects of anhydrous and hydrous ethanol on a multi-fuel engine performance, emissions and combustion.

This paper assesses the use of E85 fuel in Brazilian flex fuel light duty vehicles. E85 is composed of 85% of anhydrous ethanol and 15% of gasoline in volume base. Advantages and disadvantages of the E85 use are presented in comparison to hydrated ethanol (H100) that is currently available in the Brazilian market. Additionally, the blend H81 made by 81% of hydrated ethanol and 19% of E22 gasohol (gasoline with 22% of anhydrous ethanol), resulting on a fuel with 15% of gasoline was also investigated. The main difference between E85 and H81 is the water content due to the use of hydrated ethanol. As the E85 is not available in Brazil, this is the correspondent feasible mixture with commercial fuels in the country. Both fuels were assessed and compared to hydrated ethanol regarding cold start, cold driveability, speed recovery, pollutant emissions, fuel economy and deposit formation with engine and vehicle tests performed in the Petrobras Research Center (CENPES) laboratories.