Development and Validation of Light-Duty Vehicle Modal Emissions and Fuel211 Consumption Values for Traffic Models

摘要

A methodology for developing modal vehicle emissions and fuel consumption models211u001ehas been developed by Oak Ridge National Laboratory (ORNL), sponsored by the 211u001eFederal Highway Administration. These models, in the form of look-up tables for 211u001efuel consumption and emissions as functions of vehicle speed and acceleration, 211u001eare designed for simulations such as the Federal Highway Administration's TRAF-211u001eseries of models. These traffic models are used to evaluate the impacts of 211u001eroadway design on emissions and fuel consumption. Vehicles are tested on-road and 211u001eon a chassis dynamometer to characterize the entire operating range of each 211u001evehicle. Engine parameters are measured on-the-road as functions of vehicle speed 211u001eand acceleration while driving the cars through their entire operating envelope. 211u001eFollowing road testing, the vehicles are driven on the chassis dynamometer while 211u001emaking transient and steady-state emissions and fuel consumption measurements as 211u001efunctions of the same engine parameters. The two data sets are merged numerically 211u001eto deliver data-based models of fuel consumption and emissions as functions of 211u001evehicle speed and acceleration. As a validation exercise, the models were used to 211u001epredict cycle emissions and fuel consumption and the results were compared to 211u001ecertification-type tests on a different population of vehicles. Results of the 211u001everification exercise show that the developed models can generally predict cycle 211u001eemissions and fuel consumption with error rates comparable to the variability of 211u001erepeated dynamometer tests.