Análise de emissões e eficiência energética de um veículo de passageiros operando com diferentes combustíveis em pontos críticos do ciclo WLTC

Abstract

Performance and emissions of a compact sedan vehicle powered by a 1.4 dm³ spark ignition engine fueled with compressed natural gas (CNG), Brazilian gasoline (E27), commercial ethanol 95% v/v (E95W05) and wet ethanol 88% v/v (E88W12) were evaluated throughout the key points of the Worldwide Harmonized Light-vehicles Test Cycle (WLTC). The vehicle operating points with longest residence time on the WLTC were selected to fuel consumption and emissions evaluation at steady state conditions. In addition, different fuels performance was assessed through maximum vehicle power and torque tests. The three main operating zones of the WLTC reported in this work accounted altogether for about 34% of the time spent on the entire cycle. The results indicated a significant reduction on greenhouse gas (GHG) emissions and specific fuel consumption for operation with CNG, despite the decrease on maximum wheel power of about 10% compared to gasoline. The ethanol blends provided higher maximum wheel power and reduced emissions of nitrogen oxides (NOx), but increased specific fuel consumption, carbon monoxide (CO) and GHG emissions in comparison to CNG and gasoline. The operation with gasoline resulted in the minimum CO emissions for all fuels tested despite the highest values of carbon dioxide (CO2) and increased NOx. Even though ethanol produced little total unburned hydrocarbons (THC), the overall sum of THC, alcohols and aldehydes emissions raised an alert for this renewable fuel, whereas CNG emitted the least amount of such pollutants. Furthermore, wet ethanol provided increased combustion efficiency and reduced CO at high loads in comparison to Brazilian commercial ethanol.