Rise of the 10.7 mpg Peterbilt SuperTruck
The Long Haul to a Sustainable 10 mpg
You might have seen it parked in front of the Department of Energy (DOE) headquarters in Washington, D.C., or perched proudly as the backdrop of President Obama’s recent announcement regarding deadlines for the next efficiency and fuel economy standards for heavy-duty trucks. Displaying Cummins, Peterbilt, and U.S. Department of Energy logos, this magnificent centerpiece proceeds to show a map of the United States and then trails into an American flag. On top of the map is written: 10.7 mpg. What exactly is this blue and white two-tone backdrop? It’s the tractor-trailer combination of something called a SuperTruck, and it’s kind of a big deal. This Cummins-powered Peterbilt Class 8 tractor-trailer demonstration semitruck recently achieved 10.7 mpg during testing. While that’s not in the range of a Prius, remember this behemoth hauls quite a bit more junk in its trunk.
The term “SuperTruck” more than likely brings to recollection some sort of race truck series rather than the name of a semitruck. Perhaps Robby Gordon’s Off-Road Stadium Super Trucks or the Super Truck Racing Series come to mind. But in this case, SuperTruck actually refers to the name of a public-private, government-supported program involving semitrucks, matching grants from the DOE’s Vehicle Technologies Program as part of the 21st Century Truck Partnership, and multiple companies in the transportation industry, including Cummins and Peterbilt.
The SuperTruck program aims to meet the service demands of big rigs while increasing heavy-duty freight efficiency and reducing greenhouse gas (GHG) emissions. Basically, the Class 8 trucks of tomorrow need to be more and more environmentally friendly, and according to increasingly strict regulations and standards, compliance isn’t voluntary. Sounds easy enough, right? The SuperTruck initiative, conceived in 2009 and resulting in an approximate $284 million in spending between the DOE and the industry, is an ever-continuing fight for every small increment of big rig efficiency. The investment in efficiency is huge, and the program duration is long -- at least 5 years. As it turns out, the Cummins-Peterbilt SuperTruck is one of four SuperTruck projects; Daimler Trucks North America, Navistar, and Volvo Trucks North America were also awarded projects.
Goals & Challenges
Why the big fuss and huge outpouring of resources toward Class 8 efficiency? The statistics vary slightly, but the bottom line is that these trucks are disproportionately thirsty: In 2010 heavy-duty trucks made up about 4 percent of registered on-road vehicles, but about 20 percent of fuel consumption in the United States was attributed to these haulers. The best way to attack petroleum consumption is within this high-use market. Additionally, it’s not like trucking will ever just go away -- world truck fuel use is actually projected to grow faster than fuel use for personal vehicles. More than 2 million registered tractor-trailers move about 70 percent of all freight tonnage and log 49 percent of ton mileage.
Projects need goals and, just like other initiatives, the SuperTruck program has them. The main goal is to develop and demonstrate a 50-percent improvement in overall freight efficiency (ton-miles per gallon) for Class 8 tractor-trailers. Ton-miles per gallon equates to the number of miles 1 gallon of fuel can move 1 ton of freight. Fifty percent engine thermal efficiency, as measured on a dynamometer under a load representative of a level road at 65 mph, is another project goal. The baseline truck was a “best-in-class” commercially available ’09 model of each team’s choice.
The teams will focus on combating fuel economy losses due to the engine, drivetrain, aerodynamics, braking, rolling resistance, and accessory loads. To varying degrees, the road to loss-reduction—and conversely, efficiency -- will be achieved through truck and trailer aerodynamics, combustion efficiency, advanced waste heat recovery, overall weight reduction, hybridization, reduced tire rolling resistance, cylinder deactivation, reduced idling fuel use through battery-powered auxiliary units, use of composite materials, advanced system controls, engine downsizing, electrification of auxiliary systems, clean diesel engine technology, friction reduction, efficient exhaust aftertreatment systems, transmission advancements, and so on.
The path to drastic freight efficiency improvement isn’t without multiple challenges. Developing a multimillion-dollar prototype is one thing, but in the consumer world, low operating costs, low maintenance, and high residual value are expectations, no matter how outstanding the technology may be. Customers will require many attributes for a reasonable cost: low fuel consumption, high performance, safe operation, driver satisfaction, reliability, information systems, and emissions compliance, to name a few.
The SuperTruck program is like a massive, long-term, expensive, real-life group project that will hopefully yield efficiency improvements that can be implemented into semi fleets nationwide in the next decade. This may be the only way to develop and test these technologies. The project leads will work with multiple industry partners, as freight efficiency can’t be achieved without a holistic approach that turns theory into practice across all systems.
The Cummins-Peterbilt 10.7-mpg SuperTruck mentioned earlier has certainly received the most public attention. Original testing conducted with a Class 8 Peterbilt Model 587 achieved 9.9 mpg. The newest Cummins-Peterbilt SuperTruck, which uses an aerodynamic Peterbilt Model 579 with a Cummins ISX15 powerplant, achieved 10.7 mpg during testing between Denton, Texas, and Vernon, Texas. This testing was conducted on the same 312-mile round-trip route as the previous testing, with the tractor-trailer having a combined gross weight of 65,000 pounds running at 64 mph.
All systems on the Cummins-Peterbilt SuperTruck must be tailored around efficiency, since gains carefully calculated in one area could so easily be negated through neglect of another system. Electronic control software uses route information to optimize fuel use. A lithium-ion battery-powered auxiliary unit reduces engine idling. The next-generation automated Eaton transmission, for which Cummins and Eaton have collaborated to create efficient shift schedules, helps reduce engine-operating speeds. Cummins has also teamed up with Modine Manufacturing to develop an advanced refrigerant-based waste heat recovery system. A lightweight, aerodynamic tractor-trailer combination will also play a vital role.
The technologies of the next decade are in development and testing right now, as evidenced by this SuperTruck project. Beyond the ocean port and crowded freeway lies a world of university students diligently computing, test cells torturing engines 24/7, and mind-blowing prototypes sworn to secrecy until the right time. It is projected that all four SuperTruck projects will meet the program’s goals, if they have not met them already.
What if every Class 8 vehicle on the road was a SuperTruck? Imagine nearly 300 million fewer barrels of oil consumed and nearly a $30 billion savings on fuel each year. Per truck, that’s about 5,000 gallons of fuel and $20,000 saved annually. The SuperTruck projects are slated for completion in 2015.