Development of fuel and emission models for high speed heavy duty trucks, light duty trucks, and light duty vehicles

The current state-of-practice emission modeling tools, namely: MOBILE, EMFAC, the Comprehensive Modal Emission Model (CMEM), and VT-Micro model do not provide reliable emission estimates for high speeds greater than 80 mph since the models do not have supporting data at these high speeds. Consequently, the research presented in this paper gathers field data and develops models for the estimation of fuel consumption, carbon dioxide (CO₂), carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO₂), nitrogen oxides (NO_X), hydrocarbon (HC), and particulate matter (PM) emissions at high speeds. A total of nine vehicles including three semi-trucks, three pick-up trucks, and three passenger cars are tested on a nine-mile test track in Pecos, Texas. The fuel consumption and emission rates are measured using two portable emission measurement systems. Models are developed using these data, producing minimum errors for fuel consumption, CO₂, NO₂, HC, and PM emissions. Alternatively, the NO and NO_X emission models produce the highest errors with the least degree of correlation. The study demonstrates that the newly constructed models overcome the shortcomings of the state-of-practice models and can be utilized to evaluate the environmental impacts of high speed vehicles.