ATD Trailer Flow Control Project, ICAT 2008

This page updated March 3, 2009

Advanced Transit Dynamics, Inc.

Fuel-Efficient Active Flow Control for Tractor-Trailers

Technology and Innovation
ATDynamics seeks to commercialize active flow control (AFC) technology to improve the fuel economy of tractor-trailers by 6-10%. Established already in aeronautical and astronautical engineering, AFC uses localized energy injection to alter ambient airflow in a manner that decreases aerodynamic drag. At highway speeds, aerodynamic drag accounts for two-thirds of the fuel consumed by tractor-trailers. ATDynamics' patented AFC technology (the Technology) is installed at the rear of a tractor-trailer, around the perimeter of the trailer's doors. The Technology works by pressurizing the low-pressure vortex, or vacuum, that develops behind a box-shaped trailer as it moves forward; in aerodynamic terms, the Technology delays boundary layer separation, reducing the intensity with which the vacuum inhibits the trailer's forward motion.
Emission Benefit
The Technology is an emission-preventing aerodynamic device. It decreases fuel consumption of tractor-trailers by 6-10%, corresponding to a proportional reduction in greenhouse gas (GHG) emissions. Emissions from tractor-trailers are mobile source emissions attributable to IPCC category 1A3biii – Heavy-Duty Trucks and Buses.

According to the California Greenhouse Gas Emission Inventory, heavy-duty trucks and buses statewide emit nearly 36 MMTCO2e per year.   As a subcategory of those emissions, emissions specifically from tractor-trailers are uncertain.  However, the ARB's estimate of 1.2 million nonlocal “box” trailers traveling on California highways provides a reasonable basis for estimating the emissions reductions achievable by the Technology. Assuming that these trailers travel 50,000 miles per year while hitched to tractors that average 6 miles per gallon; that the Technology's generates fuel-efficiency gains of 6-10%; and that amount of CO2e per gallon of diesel is 22.38 pounds; then under an ideal scenario of universal adoption the Technology would reduce between 6.1 MMTCO2e and 10.2 MMTCO2e.
Project Description
The proposed project will demonstrate the use of AFC technology to improve the fuel efficiency of tractor-trailers by 6-10%. This range is substantiated by laboratory-proven fuel-efficiency gains and accounts for – but does not assume the usefulness of – opportunities for further optimization.

Single-day track testing of the initial demonstration unit of the Technology will validate its fuel efficiency gains as soon as the unit is installed – resulting in immediately publishable results that can be used generate industry press coverage of the Technology. The results will also enable the Technology to be certified under the U.S. EPA SmartWay Partnership; certification is a prerequisite to becoming a compliance tool under the AB 32 Heavy-Duty Vehicle Greenhouse Gas Emission Reduction Measure. Track testing will be conducted at the nearest automotive proving ground that is available following the installation of the initial unit of the Technology: either the Hyundai-Kia California Proving Ground in California City, California, or the Toyota Arizona Proving Ground in Phoenix, Arizona. ATDynamics has business relationships with the operators of both proving grounds.

On-road testing will measure the performance of all three demonstration units over the course of six months of normal trucking operations. It will measure not only the fuel efficiency gains of the Technology, but also its usability and durability from the perspective of drivers and fleet managers. The five-month duration of on-road testing ensures that the Technology will be exposed to extreme temperatures and precipitation. On-road testing will take place on the intrastate and interstate routes of participating California fleets.

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Funding Amount



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