Volvo Trucks North America exceeded the DOE SuperTruck 2 freight-efficiency objective — and its own internal goals.
Photo: Volvo Trucks North America
Volvo Trucks North America’s SuperTruck 2 project, unveiled October 10, demonstrates what a laser focus on efficiency can yield. Volvo’s SuperTruck 2 achieved 50% less aerodynamic drag than the 2009 baseline VNL model truck, and a 20% improvement over the SuperTruck 1 project that was unveiled in 2016.
Between the aero improvement; a lightweight cab, chassis and trailer; and a few other changes, SuperTruck 2 yielded a 134% improvement in freight efficiency (ton-miles per gallon) over the baseline truck.
“The Department of Energy issued us a challenge for improving our freight efficiency by 100%. We set our own internal target of 120%. And at the end of it all, we’re actually able to achieve 134% improvement in freight efficiency,” said Eric Bond, Volvo’s principal engineer on the project.
What is SuperTruck?
DOE’s SuperTruck 2 program promotes research and development to improve the freight efficiency of Class 8 long-haul tractor-trailers. The program aims to accelerate the development of cost-effective advanced efficiency technologies not currently available in the market.
The SuperTruck initiative kicked off in 2010 with a goal of a 50% improvement in freight efficiency. The SuperTruck 2 project was announced by DOE in 2016.
The goal of the entire SuperTruck project is to build vehicle prototypes that push out the boundaries of both fuel and freight efficiency to levels beyond where normal research and development budgets would take them.
These are concept vehicles — science projects, if you will, or as Volvo calls it, a “live innovation lab” — that pull forward ideas and technologies that in the normal course of vehicle development might languish on bottom shelves or computer hard drives and never see the light of day because the immediate payback for the developers just isn’t there.
“Partnering with the DOE for the SuperTruck program provides an exciting opportunity to push the technology envelope to see what’s technically possible for heavy-duty transportation and which solutions can be scaled into production,” said Peter Voorhoeve, president, Volvo Trucks North America. “But equally important, which solutions don’t work for scaled production.”
Starting with Aero
For Volvo’s SuperTruck 2 project, advanced aerodynamics are the key to optimizing fuel efficiency.
The entire tractor-trailer combination was designed to displace air with minimal resistance, resulting in 50% lower drag than Volvo Trucks’ 2009 baseline. This represents a roughly 20% improvement in aerodynamic drag over Volvo Trucks’ SuperTruck 1.
Around two-thirds of the drag reduction in SuperTruck 1 over the 2009 baseline came from trailer aerodynamic treatments — optimizing the skirt and boat tail. Since SuperTruck 2 also boasts optimized trailer skirt and boat tail, most of its aerodynamic gains over SuperTruck 1 can be attributed to a brand-new cab design, including a radically different windshield, while SuperTruck 1 was a slightly modified version of a VNL 670 cab. SuperTruck 2 was a nearly clean-sheet design.
Volvo’s Supertruck 2 starts with a cab that’s wedge-shaped from front to back, including:
- A raked and wraparound windshield.
- A front end designed around a downsized cooling package.
- A fully aerodynamic trailer with gap fairings, skirts, and boat tail.
- An adjustable ride height.
Volvo Trucks also replaced the traditional hood- and cab-mounted mirrors with a streamlined camera monitoring system to reduce the drag by more than 4%.
The large wrap-around windshield is steeply raked, providing a smooth transition from the grille to the roof line.
Photo: Volvo Trucks North America
Weight Reduction
Engineers implemented several weight reduction strategies to achieve a significantly reduced curb weight of 27,000 lbs., including:
- A shorter and lighter cab.
- An aluminum chassis with a lightweight optimized drive axle system with a single composite driveshaft
- Smaller and lighter 19.5-inch wheels and low-friction tires, in collaboration with Michelin.
Volvo also surely gained some efficiency and shed a few pounds by using a 4×2 drivetrain. While not a popular option here, it’s widely used in Europe, where fewer axles get the same payload, Volvo says. The truck was designed so it could be applied to a 6×2 or 6×4 configuration, but that was not part of the specific demonstrator validation for the program.
Watch for certain design cues to appear on forthcoming Volvo VN-series trucks.
Photo: Volvo Trucks North America
Volvo Trucks worked with trailer manufacturer Wabash National to incorporate a custom, lightweight aerodynamic trailer. The goal was for an optimized aerodynamic shape of the full truck and trailer to appear as one seamless unit.
Volvo Trucks also worked with the project partner tire manufacturer to include lightweight, smaller 19.5-inch advanced low-friction tires on both the SuperTruck 2 and its custom trailer.
Volvo’s SuperTruck 2 also features a 48-volt micro hybrid system that acts as a generator with an integrated starter. This provides power for driver comfort features, including an all-electric HVAC system that allows the driver to avoid idling during rest breaks and still have power for amenities.
The hood was designed around the cooling package to create a wedge-like shape to the tractor, lowering aerodynamic drag by 50% compared to the baseline truck, a 2009 Volvo VNL.
Photo: Volvo Trucks North America
Real-World Testing
The project team deliberately focused on driving in real-world conditions for testing.
“Our testing started in the lab, with static and digital testing, but our main goal was to do on-road real life testing,” Bond says. “This truck was tested in a real world environment, on road. It was not an ideal situation with flat roads and constant speeds.”
SuperTruck 2 was tested on Interstate 73 in real-world conditions with traffic and elevation changes with a gross combination vehicle weight of 65,000 lbs.
“This is the most aerodynamic and efficient truck Volvo has built to date, and we achieved a freight efficiency that demonstrates the potential for technology innovations to be developed commercially,” adds Voorhoeve. “Our engineers have already begun implementing some of the learnings from SuperTruck 2 into our future truck models. The future of trucks is just around the corner.”
The release of Volvo’s SuperTruck 2 follows unveilings earlier this year from Daimler Truck North America in February and Navistar in June. Peterbilt and Cummins gave a sneak peek of their SuperTruck 2 project at the American Trucking Associations’ Management Conference and Exhibition last year in San Diego.
Volvo Trucks’ SuperTruck 2 will make its first public appearance at the American Trucking Associations’ Management Conference and Exhibition in Austin, Texas.
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