Transportation energy data book: edition 23 - Oak Ridge National ...

4–24
Fuel Economy by Vehicle Speed
ORNL has developed fuel consumption and emissions lookup tables for the Federal
Highway Administration, for use in their TRAF series of traffic models (NETSIM,
CORSIM, FRESIM), although more generic uses are also possible. To develop the data-
based models, vehicles are tested both on-road and on a chassis dynamometer. Engine
parameters are measured on-road under real-world driving conditions that cover the vehicle's
entire operating envelope. Emissions and fuel consumption are then measured on the chassis
dynamometer as functions of engine conditions. The two data sets are merged to produce
the final three-dimensional maps as functions of vehicle speed and acceleration. Eight well-
functioning, late-model vehicles, and one 1997 model vehicle, have been tested thus far in
fully warmed-up conditions.
Similar continuing work is planned for the Department of Energy as well as FHWA,
which will include more well-functioning, late-model vehicles, pre-control (1960's) vehicles,
malfunctioning high-emitter vehicles, light-duty diesel vehicles (cars and pickup trucks),
alternative fuel vehicles, and possibly heavy-duty diesel vehicles. ORNL will also be
developing cold-start algorithms to enhance the existing models, since emissions and fuel
economy generally improve as vehicles warm up to normal operating temperatures.
For further information regarding this study please contact:
Scott Sluder Phone: 865-241-9133
Fuels, Combustion, and Engine Technology Fax: 865-241-1747
P.O. Box 2009, Building 9108 email: sluders@ornl.gov
Oak Ridge, TN 37831-8087
TRANSPORTATION ENERGY DATA BOOK: EDITION 23—2003