General Motors and the U.S. Army recently unveiled a diesel-hybrid military pickup that offers a glimpse into the very possible future of RVs. Designed by GM Military Truck Operations, the vehicle is part of GM’s Commercially Based Tactical Truck (COMBATT) program, which uses readily available commercial technology to reduce the cost of developing and acquiring light tactical vehicles, according to GM.
In that vein, the truck is based on a Chevrolet HD Crew Cab four-wheel-drive (4WD) pickup with Quadrasteer and is powered by a 6.6-liter Duramax diesel engine. But instead of an Allison 1000 transmission, the truck uses a split-power Continuously Variable Transmission (CVT) that incorporates integral electric motors. The electric motors assist the diesel and provide extra drivetrain power during high-demand times, such as starting from a dead stop, and the motors serve as regenerative generators during braking and other times of low demand.
Energy generated by the system is stored in a lightweight nickel-metal-hydride (NiMH) battery bank that weighs one-third less and is half the size of lead-acid-battery-based storage systems. This hybrid layout increases fuel economy 20 percent over a standard diesel power plant, and 25 to 40 percent over conventional gasoline-powered trucks, according to GM.
But impressive fuel economy is just one aspect of this vehicle that RVers would find of interest. The truck also uses a fuel-cell Auxiliary Power Unit (APU) that replaces the loud engine and battery-based stationary generators the Army uses now for auxiliary power. Can you imagine an AC generator that is absolutely silent and produces clean, drinkable water as its exhaust? It sounds like something from a science-fiction movie, but it is a reality in this vehicle. Designed and built by GM’s strategic fuel-cell alliance partner, Hydrogenics Corporation, of Mississauga, Ontario (24 percent owned by GM), the APU is a 5-kW proton-exchange membrane (PEM) regenerative fuel-cell system capable of producing electricity and hydrogen in remote areas.
When the vehicle is driven, the PEM electrolyzer uses electricity generated by the hybrid system to break down water into hydrogen and oxygen. The hydrogen is stored in a metal hydride container, GM’s first application of a solid-state storage device. Later, when the engine is turned off, the stored hydrogen is mixed with oxygen from the air and fed into the fuel cell to produce electricity. The byproduct is pure water, which is stored to repeat the cycle. The storage unit provides enough gaseous hydrogen to operate for three hours at a peak power of 5 kW, or five hours at an average output of 3 kW — and the only sound is that of quiet air-intake fans, similar to those used on a computer.
With characteristics such as these, a fuel-cell APU in an RV application could be located anywhere — even indoors — and because it uses very few moving parts, its maintenance costs would be far less than a standard AC generator powered by an internal-combustion engine. Furthermore, an APU provides six to 10 times the endurance of battery-based systems of comparable power, is more efficient in cold weather than batteries and eliminates any issues related to toxicity and recycling. Say goodbye to your inverter system!
“This defense project is a great opportunity to put large numbers of diesel hybrids and stationary fuel-cell units in operation in the interest of national security,” said Larry Burns, GM vice president of research and development and planning. “We also anticipate that it will accelerate cost-effective and durable civilian applications of hybrid-electric vehicles and fuel cells. As an early customer, the military will help drive down costs, increase our learning and spur the eventual development of a hydrogen-based economy.”
Perched on the back of the truck is what appears to be a windowless camper shell, which is essentially what it is, though it is more high-tech than what you’re likely to see at your local campground.
Good fuel economy and a silent auxiliary power source make this new GM concept sound like it would be a natural fit for a future RV.
