Battle of the SuperTrucks
Freightliner SuperTruck claims to be 115% more freight-efficient than a baseline 2009 truck
BACK in 2009, the U.S. Department of Energy issued its SuperTruck Challenge. The programme provided funding for truck manufacturers to design and build a prototype vehicle that was at least 50% more freight-efficient than a baseline 2009 truck.
Daimler Trucks North America recently unveiled its response — the Freightliner SuperTruck. It goes beyond the 50% figure, with a claimed efficiency increase of 115%.
The truck was created through a collaboration between Daimler-owned companies Freightliner, Detroit Engines, Mercedes-Benz and Fuso.
Much of its increased efficiency is due to better aerodynamics. This was achieved partly through a very streamlined tractor that includes features such as adjustable ride height, rear wheel fairings, articulated side extenders that bridge the gap between tractor and trailer, and ventilation slats in the grille that close when the vehicle is travelling at highway speeds.
That streamlining proceeds back to the trailer, where side skirts channel air past the wheels and away from the underside, while rear fins keep turbulence from building up in the space behind the trailer. As a result, the SuperTruck is a claimed 54% more aerodynamic than the baseline truck.
A lot of emphasis was also placed on using lightweight materials, and reducing friction. This includes a tractor frame design that requires fewer crossmembers, a lighter rear suspension, and custom Michelin tyres made with a rubber compound that decreases rolling resistance. Utilising these approaches and others, a total of 318 kg was shaved off of the tractor.
Perhaps not surprisingly, the SuperTruck also has a hybrid diesel/electric drive system. As a means of boosting its battery power, however, it utilises a waste heat recovery system which harvests thermal energy from the hot exhaust.
The custom-designed low-friction 10,7-litre engine, meanwhile, manages an impressive 50% brake thermal efficiency (which was another stated goal of the SuperTruck Challenge).
Other efficiency-boosting features that were additionally incorporated include rooftop solar panels on the trailer that can independently power its cargo-cooling system; an exhaust aftertreatment system that allows the engine to run at higher temperatures and pressures; and a GPS-based predictive system that shifts gears and adjusts speed, based on the upcoming terrain.
The 115% figure was arrived at based on a five-day, 500 km round trip route on Texas Interstate 35 between San Antonio and Dallas, at a weight of 29 484kg GVWR (gross vehicle weight rating) and a speed of 104 km/h. Its actual fuel efficiency on that trip was 19,3 litres per 100km, which is reportedly about twice what most trucks are able to attain under similar conditions.
Freightliner’s new SuperTruck, designed to meet the U.S. Department of Energy-issued SuperTruck Challenge for better efficiencies.