Volvo’s SuperTruck 2 project smashes project goals with 134% improvement in freight efficiency
Dark, sleek, and futuristic. For the better part of a year, Volvo has received calls to their Greensboro headquarters about an unusual looking truck running on local highways. In spite of the questions, engineers and designers on the project team stayed quiet, gathering performance data for their one of a kind design. The results are in and Volvo’s distinctive SuperTruck 2 is officially the company’s most efficient and aerodynamic tractor ever.
Envisioning a more efficient future of trucking
The original SuperTruck project, which began in 2011, was created by the Department of Energy (DOE) with the goal of improving the freight-hauling efficiency of Class 8 trucks (on a ton-mile per gallon basis). The endeavor aimed to push the envelope in research and development, hoping to accelerate the creation of new technologies that could quickly be incorporated into real-world situations.
When the concept Volvo SuperTruck 1 vehicle was completed in 2015, it exceeded the DOE’s main goal of improving freight efficiency by 50% through a combination of aerodynamics, weight reduction, and numerous powertrain modifications. Final calculations revealed an 88% improvement. Better still, Volvo was able to incorporate many of these enhancements into the VN line beginning in 2016.
Raising the bar
The SuperTruck 2 concept project began at the end of 2016, with the DOE asking for even greater innovation. They set goals which included a 100% improvement in vehicle ton-miles per gallon, when compared to a best-in-class 2009 truck. Volvo took that one step further and set an internal stretch goal of 120% improvement. No pressure.
“I would say it's a chance for engineers to pursue technologies and ideas beyond the boundaries of what they’d normally have the opportunity to work on,” says Eric Bond, Volvo SuperTruck 2 project manager and principal engineer. “The team took a lot of the learnings from SuperTruck 1 and were able to apply them to SuperTruck 2.”
Aerodynamics is an immediate place to start looking for improvements. This time it included a focus on the entire vehicle, including the trailer. “As an aerodynamicist, it's your dream to be able to design the entire vehicle, from the front bumper all the way to the trailer tail,“ explains Raja Sengupta, Volvo Trucks senior expert engineer for aerodynamics. “Normally, we don't get to work on the trailer—the trailer manufacturers do. But with SuperTruck, we get to own the entire solution. And the end result was the most aerodynamic tractor-trailer system we’ve ever built.”
“It’s your dream to be able to design the entire vehicle, from the bumper all the way to the trailer tail.”
RAJA SENGUPTA, VOLVO TRUCKS SENIOR EXPERT ENGINEER FOR AERODYNAMICS
Sengupta notes it’s important to focus on the little things too. “Things like the windshield, the shape, the fully wedged cab, those are obvious. But there are a couple of cool things that nobody would know about. For example, the opening in the bumper. It takes air from the high-pressure stagnation zone and redirects it to the wheel well, to pressurize it and minimize outside air intrusion into the only part of the truck that isn’t fully shielded. It's the little things like this that make the whole vehicle come together.”
Failure is a requirement
The entire reasoning behind the SuperTruck project is to push the envelope. To see what works—and what doesn’t. And then apply these discoveries later on. Risks and temporary setbacks are a natural part of the process, leading to eventual gains.
Colton Kidd, SuperTruck 2 lead build technician, explains it this way, “The biggest challenge we faced is that not everything worked. It took a lot of trial and error. Some things we may have redone six or seven times, but that just means we were pushing the envelope, we were innovating. Yes, sometimes these things weigh on you. But once you get to the final outcome, it's amazing to see it work.”
Of course, there were many successes – and many innovations – in SuperTruck 2. These include a new 4x2 axle reconfiguration. “So, one driven axle, with 65,000 pounds distributed on four axles,” says Sengupta. “When we did all that, we made sure that the trailer ends up in a position that's close to the cab, to avoid airflow going into the trailer gap. This truck has a trailer gap of 35 inches, seven inches less than what we had in SuperTruck 1.”
Alex Henriques, Volvo Trucks chief designer-exteriors, speaks to his team's successes, “I would say that of the three most important components for us on the exterior of the truck, number one is the windshield. It's our most aerodynamic yet, while providing greater visibility for driver safety. Then we essentially shrink wrap the hood around the cooling package, to really maximize air performance. And then the same thing for the sides —they’re super smooth. We’ve combined these three different areas to make one cohesive shape.”
Additional vehicle improvements abound. The side mirrors? They’re gone, replaced by a state-of-the-art camera system to further improve aerodynamics. The powertrain has been optimized, featuring a 48V micro hybrid system. And because it eliminates the belt drive, the coolant pumps and fan motor run only when needed, improving engine efficiency by reducing parasitic losses. Even the cab has been reengineered, optimizing structure while reducing weight. “We redid the entire cab,” Sengupta recalls. “We maintained the cab width at the B-pillar but narrowed the A-pillar and moved the driver position inboard. That offers the driver more elbow room than today, while the wedged cab allows the airflow to go smoothly around the trailer.”
It takes a village
There were many partners and suppliers involved to create the SuperTruck 2 concept vehicle. Michelin helped create lighter, low rolling-resistance tires to further improve fuel efficiency. Wabash reduced trailer weight with custom aero devices and suspension adjustments. Bergstrom redesigned the compressor box with straighter tube routing to accommodate the 48V compressor and provided an advanced climate control. Even the University of Michigan was involved, providing research on the cost-effective Miller cycle valve strategy-which can reduce the power needed to drive the engine.
“It really was a full team effort,” adds Bond. "We had vehicle engineering, powertrain engineering, prototype support, technicians in the workshop, suppliers, and partners. It really took the full team coming together. Obviously, without the support from the Department of Energy, we would not have had the success that we had with this project.”
The final result is more than noteworthy. “In the end, we were actually able to achieve, not 120%, but a 134% improvement in freight efficiency,” Bond remarks with pride.
"We were actually able to achieve, not 120%, but a 134 % improvement in freight efficiency."
ERIC BOND, VOLVO SUPERTRUCK 2 PROJECT MANAGER AND PRINCIPAL ENGINEER
Henriques sums up the team’s view of the project and its achievements, “When I saw the truck for the first time coming down the road, it just looked like nothing else out there right now. Because there is nothing else like it. And we think that’s awesome.”
“When I saw the truck for the first time coming down the road, it just looked like nothing else out there.”
ALEX HENRIQUES, VOLVO TRUCKS CHIEF DESIGNER-EXTERIORS
SuperTruck 2 by the numbers:
- DOE Original goal: 100% improvement in vehicle ton-miles per gallon
- Volvo Stretch goal: 120% improvement
- Final performance result: 134% improvement
- 20% better aerodynamics than ST1
- 50% aero improvements over baseline 2009 VNL
- 26,400 lbs. curb weight combined for tractor/trailer
- 325 HP 11L powertrain
- New 48V micro hybrid system
- 4x2 axle configuration
- 19.5” lightweight, low rolling-resistance tires
- $40M project cost ($20M DOE/$20M Volvo)
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