On-board monitoring and simulation of flex fuel vehicles in Brazil

Abstract

On-road measurement of vehicle tailpipe emissions, analyzing the data and developing a model, is very important to identify and recommend improved design and management approaches for the transport sector. A light-duty vehicle, the flex-fuel Nissan Versa equipped with a 1.6 liter engine and manual transmission was monitored in real operation. The on-board monitoring equipment consisted of a five-gas analyzer for CO, HC(CH 4), NO x, CO 2 and SO 2 in addition to dry systems, with sample lines directly connected to the tailpipe, and an on-board diagnostics (OBD II) connector, GPS, including other additional parameters monitoring (i.e. data logger with embedded microcontrollers). The operating parameters registered in this vehicle were: vehicle speed, engine speed, fuel consumption, angle position of the throttle valve, cooling water, oil and exhaust gas temperatures. The measurements were performed using gasoline with 27%, and 100% ethanol blends (E27 and E100 respectively, where E27 is used in emission certification). The vehicle-experiment (driving pattern) was realized in an urban route in the Fortaleza City, Brazil, under typical traffic conditions. The analysis indicates that the average emission rates (kg/h) for CO are more than a factor of 10 higher to NO idling emissions. AVL CRUISE integrated with AVL BOOST software were used to model the vehicle and the flex-fuel engine engine in both certification driving cycles and real operation ones. Real operation data is used to validate the model.