It's a bird...it's a plane...it's SuperTruck

A vehicle’s efficiency has always been an important aspect of its design and is even more so today as gas prices continue to rise while emissions regulations grow more stringent. The transport industry has been especially cognizant of this because of how significantly the efficiency of a vehicle can affect the company’s bottom line. According to the U.S. Dept. of Energy (DOE), Class 8 trucks haul approximately 69% of all freight tonnage and use more than 20% of the fuel consumed in the U.S.

In 2010, the DOE’s Vehicle Technologies Program initiated the SuperTruck Program, a DOE-funded industry cost-shared project. The goal of the five-year program is to design a heavy-duty Class 8 truck which demonstrates a 50% improvement in overall freight efficiency measured in ton-miles per gallon. To ensure there is total vehicle improvement, 30% of the efficiency must come from the tractor and trailer, while the other 20% should come from the engine. Along with the overall efficiency, each vehicle’s engine needs to show 50% brake thermal efficiency as well as a path to 55% brake thermal efficiency.

In January 2010 the DOE awarded three cost-shared projects to Cummins Inc., Navistar Inc. and Daimler Trucks North America LLC. Volvo Group joined the SuperTruck program in June 2011.

Cummins

Cummins Inc., Columbus, IN, was one of the first companies to get involved with the SuperTruck Program. While Cummins is the team lead, the company is working very closely with Peterbilt Motors Co., Denton, TX, as well as various component suppliers to develop a fully integrated vehicle. 

Scott Newhaus, Assistant Chief Engineer of Product Development Responsible for the SuperTruck Program at Peterbilt, says working on a project like this is exciting because it’s about the entire vehicle. “It’s not just the tractor, it’s not just the engine,” says Newhaus. “It’s the whole system working together, which is really exciting for us.”

Responsible for the vehicle’s engine system, Cummins has been working with Modine Mfg. Co., Racine, WI, to develop a waste heat recovery system to increase efficiency. The refrigerant-based system collects exhaust heat from various sources, such as the turbocharger or aftertreatment system, and expands the collected heat across the turbine to keep the engine cool.

Cummins is also working to further optimize the engine by reducing parasitic pump power, as well as increasing the efficiency of the engine’s turbochargers by looking at the combustion process. Improvements to the aftertreatment system will ensure the system does a better job of cleaning up NOx (nitrogen oxides) to meet emissions regulations, says David Koberlein, Cummins’ Principle Investigator for the SuperTruck Program.

Improvements from Peterbilt include reducing loads through the use of lighter weight materials, such as aluminum. Adjustments to the aerodynamics of the tractor and trailer are also in the works to reduce the vehicle’s drag. Peterbilt is working with Delphi, Troy, MI, on a solid oxide fuel cell (SOFC) for idle management. Additional technologies include an advanced transmission by Eaton Corp., Ann Arbor, MI, to reduce energy lost through the shifting process as well as driver displays. Newhaus says the driver displays will be an important piece of the puzzle, “ensuring [drivers] know what’s going on with the vehicle and how to react with the vehicle to gain the maximum efficiency.” As the team’s end user partner, U.S. Xpress of Chattanooga, TN, is providing feedback on whether the technologies developed for the SuperTruck will be a valuable commercial investment for customers as well.

Weight is added with new technologies for improved emissions and fuel performance. Vinod Dugul, a consultant for Cummins, says the entire team is working to reduce overall vehicle weight through the use of new technologies and materials. Peterbilt’s Newhaus says weight is no longer an issue, though optimization is a continuous process.