BURBANK, Calif.—As the Chevy Volt inches closer to production, the idea of scaling up its powertrain concept to larger vehicles is tantalizing. So when Raser Technologies unveiled its 100-mpg-equivalent Hummer H3 at the 2009 SAE World Congress, it grabbed headlines. But we wanted to get a taste of what it's like to slide behind the wheel of Raser's plug-in prototype on real roads. We got the chance two days ago as the Raser crew stopped briefly in Southern California before heading up to Sacramento for a drive event with Governor Schwarzenegger. So is the 100-mpg Hummer ready for prime time? Let's find out. —Ben Stewart
The Specs
The Raser Technologies Hummer is a combined effort between the company, integration partner FEV and General Motors. The powertrain is similar to that of the Volt in that this is an electric vehicle that uses an internal combustion engine to charge the batteries when the original plug-in charge of the packs is depleted. And unlike a conventional hybrid, that engine does not power the vehicle. The Raser Technologies-developed electric traction motor develops 200 kW peak and is mated to the front of the stock GM 4L60E four-speed transmission, which sends torque through the stock transfer case and to both the front and rear axles. The powertrain provides 40 miles of electric range before the gas engine kicks in to charge the packs for around 400 miles of total range.
Under the hood is a turbocharged GM Ecotec four-cylinder engine, similar to the unit used in the Pontiac Solstice GXP. That engine turns a generator that helps charge the three battery packs. Two of the lithium-ion battery packs are mounted on either side of the undercarriage and one is located at the rear of the chassis. In total, the packs provide 41 kWh. The batteries on this vehicle are lithium-ion "super-polymer" units from Canadian supplier Electrovaya. But Raser is also working with Enerdel and Korean supplier SK. The packs are liquid-cooled, as is the electric motor. Raser PHEV Program Manager and former Honda Engineer KC Jones says, "Lithium battery suppliers come to the automotive market fresh—it isn't the same as consumer electronics or power tools—it's new ground for them. So in addition to having great chemistry, they need to develop a durable package that can withstand, say, rough road driving for up to 10 years."
This truck has an AC converter mounted in the cargo hold to provide export power for situations as diverse as a camping trip or emergency power outage. Once in production that generator will be integrated underhood and will provide a valuable tool for fleet sales to utility companies who rely on mobile power sources. Though Raser used the H3 to prototype their range-extended powertrain, the system is scalable to full-size pickups like the Ford F-150 or Chevy Silverado.
The Drive
Twist the key and, as with most EVs, you don't hear much. The gauge cluster lights up and shows a few trouble-code warning lights—as you might expect in a prototype. On the dash above the stereo and HVAC controls is a display that shows how the energy is flowing to the various systems on the truck. In production models, Raser says this display would be integrated into the stock navigation screen.
Since the electric drive is routed though the conventional four-speed automatic, you just pull the gearshift back to "D" and squeeze the throttle as you would in any car. But the sounds are not entirely silent. Since there is no longer a torque converter, Raser must provide adequate line pressure to the transmission, so you hear the muted buzz of the pump until the truck moves forward. Raser uses a conventional hydraulic steering pump too, but that can only be heard from outside the vehicle.
Unlike many electric vehicles, this Hummer doesn't leap off the line. The H3 is a development vehicle, and the electric motor provides around 300 lb.-ft. of torque at zero rpm, so to keep parts from breaking, the thrust from a full-throttle launch is soft. According to Jones, as the testing evolves the company will incorporate a steeper power ramp-up. Once underway, the ride is essentially silent, with the exception of a mild hum from the all-terrain tires. Our drive was short, just 15-minutes long. That distance wasn't sufficient to deplete the batteries enough to have the Ecotec begin charging for the packs. But that part of the puzzle is still very much in development. In theory, the four-cylinder is only used as a generator and would run at a constant rpm. But Jones says that may not be ideal for every situation. If a customer were sitting at a traffic light and the truck's engine was running along at, say, 3000 rpm, it might seem quite odd to the driver—and other motorists too. So Jones says the ultimate solution would be to have the system slow the engine to idle in certain situations so that it mimics conventional vehicles.
A keen eye will notice that the Raser H3 sits a bit lower than a regular production Hummer. That's because its new powertrain adds approximately 1000 pounds to the 4700-pound truck. On the road, even at 30 to 40 mph, you can certainly feel that extra weight. We'd guess it would seem less noticeable on a full-size pickup. Jones mentioned that the powertrain probably has more battery power than it needs right now. He thinks the final production system may only require 26 to 28 kWh. If true, the system's total weight would drop by a few hundred pounds.
The Bottom Line
The Raser H3 is still very much a prototype. But the company expects to have the first two vehicles in "alpha" testing with San Francisco-based Pacific Gas and Electric later this year. The company has 12,000 "soft" orders from fleet customers. So in 2010, the company will begin "beta" testing with some of them using Hummer H3s, Hummer H3Ts, Chevy Silverados and Ford F-150s. They expect to begin high-volume production in 2011.
The cost of the system, Raser says will be approximately 25 percent of the total cost of the fleet vehicle. And the company is working with the OEMs so that when the vehicles are up-fitted with the powertrain, the conversion maintains as much of the factory warranty as possible. We hope to test one of these trucks as Raser moves closer to production.
