Freightliner’s Supertruck Doubles Tractor-Trailer Fuel Economy

(3BL Media/Justmeans) - Back in December, I wrote about the government’s efforts to improve the fuel economy of the thousands of tractor-trailer trucks that crowd our highways accounting for millions of gallons of diesel fuel and tons of carbon emissions. One prong of this effort was a five-year $115 million DOE project that challenged truck makers to see if they could achieve a 50% reduction in fuel consumption.

Now, Freightliner has announced their success, as they unveiled their Supertruck.

The 65,000 pound semi, which is powered by an 11-liter hybrid diesel engine, and shrouded with a bevy of aerodynamic features, comfortably surpassed the target by 15%, with a demonstrated fuel economy of 12.2 mpg, more than twice the average of trucks on the road today. The test drive was performed between Dallas and San Antonio Texas.

The list of features that combined to achieve this result is truly impressive.

The company took a clean slate approach to the project, evaluating every aspect of the vehicle, utilizing an incredible 8 million hours of computation in the process. Freightliner, which is a subsidiary of the Daimler organization, leveraged expertise from numerous partners around the world.

Aerodynamics played a huge role in the transformation. For starters, a lot of wind drag is produced by the air entering the engine compartment to cool the radiator. Freightliner came up with an innovative grille design that opens when engine cooling is needed and closes when it is not. Surprisingly, over two-thirds of the benefit comes from the trailer. A nose cone, side skirts and a boat tail all contribute to improved aerodynamics. A cab extender also closes off the gap between the trailer and the cab, an area of high turbulence in conventional semis.

The new truck utilizes the Detroit Integrated Powertrain, which allows drivers to downspeed the engine, regardless of road speed, to reduce frictional losses. It also takes advantage of Intelligent Powertrain Management (IPM) technology, which uses pre-loaded terrain maps and GPS to know the route ahead so that it can automatically adjust transmission and engine functions. It can even shift the transmission into neutral and coast under certain circumstances.

Most of the accessories run off the battery, eliminating parasitic losses and allowing the divers to connect to auxiliary power sources when parked. It also means that the solar panels installed across the top of the trailer’s roof can power the air conditioner on hot, sunny days. The power steering system is on-demand, which assures that it only uses power when it needs to.

A novel heat recovery system, actually circulates water through the engine, then boils it to produce additional electrical power.

Said Derek Rotz, ‎Senior Manager, Advanced Engineering at Daimler Trucks North America, “The Supertruck program provided us the opportunity to see what is really possible, not today, not next year, but many years into the future.

Lightweight materials in the frame and the sleeper cab also help improve fuel economy.

A truck like this would save today’s average trucker 10,000 gallons of fuel per year. The Supertruck is not yet commercially available, though many of its features are being incorporated into new models as they come out.

Image courtesy of Freightliner