By pushing the boundaries of heavy-duty vehicle efficiency, Volvo’s SuperTruck vastly exceeded the U.S. Department of Energy’s initiative to build a highly efficient truck that strengthens U.S. manufacturing and reduces dependence on foreign oil.
In 2011, Volvo accepted the U.S. Department of Energy's (DOE) challenge to build a highway truck prototype with a target of 50 percent improvement in overall freight efficiency compared with 2009 truck models. Volvo Trucks raced to meet the challenge, tapping more than 200 people to be part of the SuperTruck project, an effort that required re-thinking everything from the front bumper to the back of the trailer. The effort paid off. Volvo Trucks surpassed the 50 percent goal and rolled out a SuperTruck capable of 88 percent greater freight efficiency along with exceeding 12 mpg.
Keith Brantley, project manager, advanced complete vehicle, says leading the charge on this project was a chance of a lifetime. His team worked together to create the SuperTruck, complete with improved aerodynamics, increased powertrain efficiency, and lower tractor and trailer weights. “I truly believe we introduced the future of trucking while reducing dependence on foreign oil,” Brantley says.
INTEGRATING PERFORMANCE WITH AERODYNAMIC DESIGN
Brantley began his SuperTruck research by asking a lot of questions. His job included finding ways to reduce the combined truck and trailer weight, and he sought out experts in everything from air conditioning to tires to the chassis frame assembly.
Brantley’s team worked with suppliers and academic partners to develop new ways to use lightweight materials like carbon fiber without compromising performance or safety. While they tested several materials that didn’t make it into the final SuperTruck, including recycled carbon fiber, the knowledge gained in material science will be applied to future programs.
When the SuperTruck was assembled, the tractor and trailer weighed 3,200 pounds less than the 2009 VNL model. The redesigned chassis, which is made almost entirely of aluminum, was half the weight of a traditional chassis and had the biggest impact on the weight reduction goal.
"From an aerodynamics perspective, SuperTruck was a unique opportunity to look at the complete system and optimize it to the specifi c duty cycle, weight distribution — everything the program was targeting.”
Raja Sengupta, PH.D., lead engineer for aerodynamics
Raja Sengupta, Ph.D., lead engineer for aerodynamics, says Volvo Trucks’ computer-aided engineering allowed the SuperTruck team to reimagine nearly every part of the tractor and trailer without costly prototyping. “We redesigned the front end, the cab exterior pieces, the chassis fairings, the side deflectors, the roof. All of it is new,” he says. “From an aerodynamics perspective, SuperTruck was a unique opportunity to look at the complete system and optimize it to the specific duty cycle, weight distribution — everything the program was targeting.”
A surprise result from engine testing led to even more improvements to SuperTruck’s aerodynamic performance. The heat rejection from the improved powertrain system was lower than expected, so Volvo Trucks was able to reduce the size of the cooling package, reduce the grill opening, and make the front end of the truck more aerodynamic.
Customers won’t have to wait for several of the aerodynamic improvements found on SuperTruck. Volvo Trucks’ 2016 VNL series has flared chassis fairings that improve airflow around the drive wheels and tractor-trailer gap. A redesigned bumper and lower deflector direct the air to the rear and reduce turbulence. The roof air deflector also reduces turbulence between the cab and trailer.
POWERING THE FUTURE
John Gibble keeps a few engine parts on his desk. They’re reminders of the five years he spent leading a complete engine redesign for SuperTruck. Gibble’s desk also holds a framed photo of his children, ages 9, 7 and 4. Looking at it, he’s reminded of what this super-efficient concept truck will mean for future generations.
Gibble, the senior project manager responsible for advanced powertrain development, spent the first few months of his SuperTruck work collecting ideas for improving engine efficiency. His team received hundreds of suggestions from engineers across the Volvo Group — some for single components and others for complete systems.
“My main job was to help our engineering teams mature the concepts that showed promise and make sure they would work as part of the overall system,” Gibble says. “We took a fresh start at the whole engine and designed it to match our I-Shift transmission and axles. Every time a concept showed its valor, we added it to the engine build.”
Because of the efficiency gains with SuperTruck, the team was able to downsize to a Volvo D11 engine with 425 horsepower. The improvements included an upgraded fuel injection system, cooling system, oil system, wave pistons, turbo charging system and more. The most groundbreaking technology was the addition of the waste-heat recovery system, which converts heat normally wasted in the exhaust into energy for powering the truck. This system alone resulted in a 3 to 4 percent fuel efficiency improvement.
“To my knowledge this is the most efficient diesel engine Volvo Trucks has ever built, and the most efficient long-haul truck we’ve ever run on the road,” Gibble says. “Our future products will be designed around this concept vehicle.”
“To my knowledge this is the most efficient diesel engine Volvo Trucks has ever built, and the most efficient long-haul truck we’ve ever run on the road.”
John Gibble, senior project manager responsible for advanced powertrain developerment
Three of the engine advancements developed through SuperTruck research — the wave piston, turbo compounding system and common-rail fuel injection system — have already made their way into Volvo Trucks’ 2017 powertrain lineup. “These three features will save Volvo Trucks customers around 20 million gallons of fuel in 2017 alone, which equates to $50 million dollars,” Gibble says. “This is how SuperTruck is already making a difference.”
Volvo’s SuperTruck features a sleek design, including carbon fiber on the roof, hood and side fairings. In addition, the mirrors were replaced by cameras that helped with aerodynamics.
PUSHING FUEL EFFICIENCY BOUNDARIES
SuperTruck is a sleek, one-of-a-kind machine. It has a shorter front end than conventional trucks on the road today, and the hood has a sharper downward slope. Lightweight fairings run the length of the tractor and trailer. Cameras have replaced the rearview mirrors. The sunroof and side windows have been removed — offset by a solar panel that provides free energy for battery charging. It also powers interior lights and a fan to draw fresh air inside.
In September Volvo Trucks delivered its SuperTruck to DOE officials in Washington, DC — a truck the company spent nearly $40 million to design and build. In addition to more than 200 Volvo employees, dozens of suppliers and universities with expertise in combustion science and computer modeling supported the project. While the SuperTruck engine was developed and built in Hagerstown, Maryland, the truck was designed and assembled at the company’s Greensboro, North Carolina-based Technical Center.
With its goal of improving freight efficiency — meaning more payload carried for less fuel — by 50 percent compared to 2009 baseline model trucks, the SuperTruck program set the bar high. But Volvo Trucks went even higher, achieving an 88 percent improvement over its 2009 VNL 670 equipped with a D13 engine. In initial road tests, fuel economy jumped 69 percent, and payload capacity increased 10 percent. Powertrain brake thermal efficiency reached 50 percent. Aerodynamic drag was reduced 42 percent. Fuel economy exceeded 12mpg.
“It’s an awesome truck, and we built it from scratch. It feels good to have been a part of it.”
Keith Brantley, project manager, advanced complete vehicle
“This order of magnitude leap reflects the amount of work that went on behind the scenes,” says Pascal Amar, principal investigator, SuperTruck project. “I’m proud of the way our entire team answered the challenge.”
SuperTruck was the first time Volvo Trucks has focused on improving the efficiency of both the tractor and the trailer. “We set out to prove new technologies that ultimately can become part of trucks we see on the road,” Amar says. “We started by rethinking everything, and we discovered that with every layer of engineering assumptions you peel back, you uncover new opportunities.”
Volvo’s SuperTruck exceeded 12 miles per gallon, with some test runs showing more than 13 miles per gallon. Testing occurred on state and interstate roads along the east coast, covering a wide range of road profiles including flat, rolling and hilly terrain.
CHANCE OF A LIFETIME
Many of the employees who helped create SuperTruck consider it the high point of their career. Or “the most fun I’ve ever had at work,” Brantley says.
“We had people knocking on our doors every day asking how they could be part of this program,” Amar says. “This is what engineers love, and a program like this succeeds because you bring together the right people, and you believe in them.”
Brantley enjoyed seeing the reactions of other truck drivers when he went along for test runs. “They would ask questions about the truck and what it can do, and I’m always happy to talk about it,” he says. “It’s an awesome truck, and we built it from scratch. It feels good to have been a part of it.”
While the SuperTruck program has officially ended, the work has not. Volvo Trucks was chosen to participate in the DOE’s next freight-efficiency initiative, SuperTruck II.
“For us, SuperTruck resulted in much more than one test build,” Brantley says. “It opened up all kinds of doors, and now we’ll be taking these technologies even further. I’m looking forward to doing this again for the next five years.”
“We started by rethinking everything, and we discovered that with every layer of engineering assumptions you peel back, you uncover new opportunities.”
Pascal Amar, principal investigator, SuperTruck project