We’ve had the opportunity to design some of the world’s most precise and critical manufacturing and test facilities that serve the aerospace and aviation markets. As we continue to grow our firm, it’s only fitting that we bring this dedication to precision back to earth by forming a world-class Automotive team.
Integral to that team is Mr. Bob McLenon, PE, our Automotive Test Track Subject Matter Expert. Mr. McLenon has designed and overseen construction of some of the country’s most innovative track facilities, including multiple high-speed tracks for the Big Three as well as the Porsche Experience Centers in California and Atlanta, GA.
Bob brings a wealth of knowledge to our team and we’re excited to share some of that knowledge with our community. Important to test track owners is a recent EPA regulation that will affect the validity of data that is collected at US test tracks. Keep reading for a detailed Q&A with Bob about how owners – both independent and OEMs – can prepare or retrofit their existing tracks to meet these requirements.
Q: “What is the new regulation? When does it take effect?”
A: When vehicles are tested for emissions and fuel economy, it is usually done using a chassis dynamometer. Since the dynamometer is stationary, the loads from aerodynamic drag, friction and tire losses associated from actual road operations must be simulated. Since road-load is difficult to measure directly, the EPA has adopted the coast-down method to characterize road-load force.
- For test tracks, this means that the test road or test track should be straight, smooth and level for a sufficient distance to obtain the necessary data.
- The road or test track surface should be hard and smooth. The surface texture and composition should be similar to road surfaces commonly in use. The grade shall not excess 0.5 percent and crown should be minimal. The grade must be constant, +0.1 percent, throughout the test section.
- Tests must be conducted on the road or track in opposite directions with minimal interference from other vehicles during the data collection periods. During the data collection period, the track surface and vehicle should be dry and the track free of obstacles or significant irregularities. The absence of intermittent wind barriers near the road or track surface is preferred to reduce positional wind variations.
The vehicle manufacturer may use any test procedure to characterize road-load force using good engineering practice, but if the EPA discovers while evaluating the manufacturer’s procedures and methods that they are producing inaccurate and unrepresentative data, the EPA will refuse to accept additional test results until deficiencies are corrected.
Q: How does this regulation affect current track owners?
A: Since the EPA can perform audits, it subjects the manufacturer’s tracks to conformance testing. While they do reference the Society of Automotive Engineers (SAE) Code J2263 with a slope not to exceed 0.5%, the EPA states that the track shall be straight, smooth and level for a sufficient distance. This gives the EPA some latitude to determine how stringently they want to enforce test slopes.
Q: Will existing tracks need to be renovated or replaced? What might change about their design?
A: If tracks currently being used do not meet the EPA requirements, they may be disqualified for road-load determination. A track that is flat but perhaps has variations in the smoothness can be rehabilitated to eliminate the variations in order to meet the criteria. However, a track that has excess slope can be costly to rebuild to a flat slop of 0%, as it may require an excessive amount of cut or fill.
Q: If changes are necessary, how can owners best plan and keep costs down?
A: Proactive owners will start with an assessment of their current track facilities to verify their adherence to the EPA guidelines. Since the EPA allows manufacturers to characterize road-load force using any test procedure, track owners will need to prove that their test results are within the constraints of good engineering practice. Any procedures or methods that differ from the recommended procedure must be described in the application for certification. The EPA can conduct testing to confirm the manufacturer’s results, therefore test procedures and results need to be repeatable.
Looking for more information? Click here to contact Bob.