It’s hard to imagine that an integrated set of truck roof and side fairings, along with redesigned mirrors, can improve a highway tractor-trailer’s fuel economy by as much as 12%. Yet that’s exactly what Peterbilt Motors Co. claims its new “aerodynamic package” can do.
Available on Peterbilt Model 386 and 384 highway tractors, as well as a retrofit package that can be installed by dealers on some other models, the new aerodynamic offerings result from over a year of lab and field tests, including customer-testing by Wal-Mart Inc.
At a special ride-and-drive event at Peterbilt’s headquarters in Denton, TX, chief engineer Landon Sproull said that the aerodynamic package cuts overall tractor-trailer drag by 24% by adjusting the airflows over the top and sides of the vehicle. With every 2% improvement in drag-improving fuel economy there is a 1% boost in fuel economy, he said – a savings of $5,600 in fuel per year per truck, assuming fuel at $2.30 per gallon and the truck logging 130,000 miles annually.
It’s hard to imagine that an integrated set of truck roof and side fairings, along with redesigned mirrors, can improve a highway tractor-trailer’s fuel economy by as much as 12%. Yet that’s exactly what Peterbilt Motors Co. claims its new “aerodynamic package” can do.
Available on Peterbilt Model 386 and 384 highway tractors, as well as a retrofit package that can be installed by dealers on some other models, the new aerodynamic offerings result from over a year of lab and field tests, including customer-testing by Wal-Mart Inc.
At a special ride-and-drive event at Peterbilt’s headquarters in Denton, TX, chief engineer Landon Sproull said that the aerodynamic package cuts overall tractor-trailer drag by 24% by adjusting the airflows over the top and sides of the vehicle. With every 2% improvement in drag-improving fuel economy there is a 1% boost in fuel economy, he said – a savings of $5,600 in fuel per year per truck, assuming fuel at $2.30 per gallon and the truck logging 130,000 miles annually.
“This proprietary aerodynamic package is designed to ease the movement of air around the vehicle,” Ken Marko, Peterbilt market planning manager, told FleetOwner. In a walk-around inspection of a Model 384 equipped with the new aerodynamic offerings, Marko pointed out the features:
- New roof fairings with trim tabs push air up and over the cab and trailer.
- A new sleeper roof transition fairing smoothes out the transition of the air from the cab to the sleeper roof. The chassis fairings now have “flairs” on the end to push air out and away from the tires.
- A new 3-in. rubber extender on the sleeper cab directs air out and around the trailer sides.
- A new composite sunvisor reduces forward drag, helping direct air from the nose up over the cab roof while reducing glare.
- The external mirrors are more rounded, easing airflow around the mirrors themselves and their mounting brackets.
- The battery box/tool box is now more aerodynamically shaped to offer less under-cab drag.
This new aerodynamic package is also available for retrofit on older, traditional-style Peterbilt trucks, such as the Model 388 and 389, in addition to classic models such as the now-discontinued 379, albeit without the chassis fairings due to the design of the exhaust systems on those vehicles.
“We were really pushed by Wal-Mart to do this,” Sproull told FleetOwner. “It’s the result of a combination of engineering disciplines – wind-tunnel testing, computer-based computational fluid dynamics (CFD) analysis, our own internal fleet testing and customer testing by Wal-Mart.”
Peterbilt is also making changes to the interior designs of all its highway and vocational trucks, specifically the addition of an “in-mold” process whereby colors are embedded directly into the dashboard materials (rather than being painted on) to reduce fading and chipping over time, while also helping to reduce glare for drivers. Chris Wehrwein, a senior design engineer with Peterbilt, told FleetOwner those interior upgrades are built around a newly redesigned HVAC system that is 20% more efficient.
