Detonation: A Future for Trucks
Meeting future emissions and fuel-economy standards in medium- and heavy-duty trucks is becoming more and more of a concern for manufacturers and users alike. Over the last few years, we have seen major players in the game push to develop technology that meets more stringent requirements and still allows trucks to efficiently do their jobs.
Companies are accepting the challenge in different ways. Many OEM engine suppliers have put effort into converting and building engines that use alternative fuels like natural gas to lower emissions. Toyota Motor Corporation took a different direction and developed an upsized version of the hydrogen fuel-cell technology found in its cars, for fitment in two Class 8 test trucks. The second test truck, a Kenworth T680 tractor, features improvements derived from data of the first Class 8 tester. The Kenworth is 1 ton lighter and went 100 miles further on a fill-up, for a total of a 300-mile range. A 10 percent increase in power over the first truck was also achieved.
Fuel-cell vehicles are powered by electricity produced on board by oxygen and hydrogen. The Kenworth has a 12-kilowatt-hour lithium-ion battery and six carbon-fiber–wrapped tanks that hold 60 kilograms of compressed hydrogen gas. This combination powers twin electric motors that are good for 670 hp and 1,327 lb-ft of torque, which put them in the ballpark of a Cummins X15 Efficiency Series diesel engine.
Toyota is not the only one making inroads with hydrogen fuel cells in heavy-duty trucks. Propulsion systems developer U.S. Hybrid and Kenworth are also working together to develop a system for Class 8 trucks, as is Nikola Motors. Even General Motors, one of the largest car and truck producers in the world, has unveiled a heavy-duty fuel-cell concept truck. It looks like fuel cells are not being taken lightly; manufacturers feel the hydrogen/oxygen-filled tank is a plausible alternative power source. Consumers like United Parcel Service (better known as UPS) are looking at them, too. UPS is putting 17 custom Class 6 fuel-cell–equipped delivery vans into service to test their operational feasibility.
Using a different approach to meeting increasing standards is Shell Rotella with its Starship Initiative. The company partnered with Airflow Truck Company to design and build a hyper-aerodynamic, super-fuel-efficient concept Class 8 truck. The Starship is 100 percent carbon fiber, so it is light and strong. There are active shutters in the grille that open and close depending on temperature to balance radiator and engine-bay airflow with vehicle aerodynamics. The rest of the truck and trailer has side panels and skirts to maintain airflow and reduce rearend drag.
The Starship uses a conventional diesel engine as the main power source, but it also has a hybrid electric-axle system in place of the rear non-driven axle. The hybrid system enhances drivetrain performance when climbing grades, and in turn reduces fuel consumption. Regenerative braking is used to charge the batteries when decelerating or descending hills. The truck also incorporates other energy-saving technology, like a tire-inflation system that maintains ideal pressure, a down-speed axle configuration (high-speed rear axle components are used to drop engine rpm for better fuel economy), and an automated manual transmission.
A 48-volt battery pack is kept charged by a 5,000-watt solar array mounted on the trailer’s roof. The battery pack is used to run accessories, including cab air conditioning, an inverter, and 12-volt (a DC-to-DC converter is used) truck features. To ensure mechanical components are running efficiently and economically, Shell synthetic fluids are used throughout the vehicle.
Starship was tested on a coast-to-coast run (2,300 miles) in 2018 with a total gross vehicle weight of 73,000 pounds to see how efficient it is at hauling weight, and what type of fuel economy it is able to achieve. The truck averaged 8.94 mpg for the entire trip, with a best mpg of 10.2. (It does not sound like much compared to improvements seen in smaller vehicles, but considering how much weight they haul and that the average modern Class 8 truck gets 6.4 mpg, it is a big improvement.)
Along with mechanical innovations, there is also an influx of renewable fuels coming to the market that are designed to reduce carbon emissions. Neste is a Finnish company that is selling diesel fuel made from 100 percent renewable raw materials that are said to reduce greenhouse gas emissions by as much as 50 to 90 percent over traditional fossil diesel. The renewable fuel comes from the refinement of waste and residues, which is different than biodiesel, which is based on vegetable oil and animal fat. A fuel like this may keep oil-burners viable for the foreseeable future.
There are many different high-tech innovations being developed for Class 8 trucks. One or all of these technologies may keep the rigs hauling cargo and goods into the future. It is going to be interesting to see how modern drivetrains and trucks further evolve.