Emission estimates for an on-road flex-fuel vehicles operated by ethanol-gasoline blends in an urban region, Brazil

Vehicle emissions have become the dominant source of air pollutants in many cities. Relatively few studies have examined the impact of different ethanol concentrations into fuel on exhaust emissions from flex-fuel vehicles on real-time traffic conditions. In this study, emissions analyses of carbon monoxide, carbon dioxide, nitrogen oxides and hydrocarbons were carried out in a flex-fuel vehicle in an urban route in the Fortaleza city/Brazil. The vehicular exhaust emissions of the pollutants above mentioned were measured through a portable analyzer. Route was performed with different ethanol/gasoline blends (27%, 85%, and 100% ethanol). VSP methodology was used in this work. On-board system data used could register instantaneous emissions as a function of vehicle dynamics. It was observed that the acceleration operation mode was the major responsible for highest emissions of CO, CO2 and NOx for all blends tested. CxHy emissions of <0.005 g km−1 were registered. The results show the relevance of performing sampling in real-time traffic conditions, since the emission standards set by approved real-time traffic conditions do not often represent local reality.