Daimler Builds Twice-As-Efficient “SuperTruck” Class 8 Semi
Smooth Aero, Hybrid Power Help Truck Meet Department of Energy Goals
The Department of Energy’s SuperTruck program, which aims to double the fuel efficiency of every new Class 8 tractor-trailer, got a shot in the arm from Daimler’s entry. Revealed today at the Mid-America Trucking Show, the Michael Bay–chic Daimler SuperTruck bested all other OEM semi manufacturers in terms of both fuel efficiency and freight efficiency.
The Daimler met its goals by using currently available technologies such as engine downspeeding and the company’s Intelligent Powertrain Management (IPM). Using preloaded three-dimensional maps, IPM anticipates hillclimbs and descents, allowing the powertrain to select the right gears for the situation and optimizing battery regeneration to save electric power for when it can provide the most efficiency gains. The engine’s turbocharger is also designed for high efficiency, providing just enough turbo pressure for optimum performance, minimizing any losses or restrictions in the air system.
Arguably the most revolutionary feature of Daimler’s prodigy is the aerodynamic styling. Articulated side fairings and rear-wheel covers deploy to reduce parasitic drag at high speeds, which makes for a nearly seamless integration between tractor and trailer. Automatic ride height control lowers the semi and grille shutters close off during cruising, both of which reduce drag. The truck’s resultant aerodynamic efficiency enables it to run a downsized 10.7L diesel engine, which reduces its fuel consumption even more.
Other science-fiction–grade improvements to the truck include an array of solar panels mounted to the trailer’s roof. Those panels also run the truck’s electric-powered eHVAC, a climate control system that can maintain a comfortable cabin temperature for more than an hour without running the engine at all. A waste-heat recovery system (still in experimental stages) is attached to the truck’s exhaust, helping convert otherwise wasted thermal energy.
The final SuperTruck demonstrator ran a 5-day, 300-mile route in Texas, at a gross vehicle weight rating of 65,000 pounds at 65 mph. In those conditions, the Daimler SuperTruck achieved a trip average of 12.2 mpg, more than doubling the average fuel efficiency of today’s commercially available semis.
If that number sounds unimpressive, then consider a few things. One: Although freight trucks only comprise four percent of the vehicles on the road in the United States, they use about 20 percent of the national fleet’s overall fuel, so any improvement, however incremental, will lead to a significant decrease in fuel consumption nationwide. Two: The SuperTruck’s mileage rating is extremely impressive for such a large vehicle, remembering that the (obviously much smaller) Ram Power Wagon test vehicle from our Pickup Truck of the Year competition struggled to reach that number more often than not. And three: The Daimler SuperTruck achieved its efficiency numbers primarily through commercially available technologies, meaning the Department of Energy’s goals are feasible for most truck manufacturers.
Will we be seeing ultra-smooth semis running around on our roads any time soon? It’s not likely, as there are still a few engineering hurdles preventing the Daimler SuperTruck from entering mass production. However, as the Department of Energy says, Class 8 fleet managers are among the most eager to adopt new fuel-saving trucks, so there’s plenty of monetary motivation to bring new technology to market as soon as possible.
Source: Daimler Trucks North America, U.S. Department of Energy