| Resumo : |
Plug-in hybrid electric vehicles (PHEV) have the potential to combine the benefits of a renewable electric mix with biofuels. More recently, PHEVs have been designed to be equipped with a small combustion engine known as a range extender, thus allowing an improvement in the vehicle's range while converting fuel energy through a highly efficient pathway. Hydrated ethanol is a promising alternative to gasoline and is already available in some countries, such as Brazil. However, ethanol has a large enthalpy of vaporization, and its vaporization results in the cooling of the exhaust gas, which affects the catalyst heating, making intermittent operation with ethanol critical for its use in PHEV. Thus, this study was motivated by the need to meet the emission limits established by standards in PHEVs equipped with flex-fuel range extenders operating with both gasoline and hydrated ethanol. Therefore, a calibration was first performed to reduce the warmup phase with ethanol. An electric heater was then used to accelerate the catalyst heating, further improving emissions from the ethanol operation, and aiming to achieve future emission limits. Experimental tests were carried out on a vehicle under the FTP72 emission cycle using a chassis dynamometer. Emissions results exhibited a reduction in carbon monoxide for ethanol and significant improvements were obtained in the WTW analysis. The use of an EHC improved emissions during the heating phase, significantly reducing the emission of NOx and organic compounds. As a continuation of investigations into a REx dedicated to ethanol, an evaluation of a PFI engine operating with technologies dedicated to gasoline internal combustion engines was presented. A 1-D model of the engine was developed using AVL Boost software. The engine geometry was provided to the model while the combustion characteristics were obtained from experiments carried out in previous studies. The simulations produced data on fuel consumption for engine operation with different combinations of technologies under ideal operating conditions, exposing the best option for an ethanol-powered REx. The main motivation for this application is the use of energy sources with low environmental impact, including electrical energy coming mainly from renewable sources in Brazil and the biofuel ethanol, which provides absorption of carbon dioxide during the sugarcane cultivation cycle. |