More stories related to SAE DETROIT - The military Humvee of the future could be sporting hybrid power, if the U.S. Army Tank Automotive Research, Development and Engineering Center (TARDEC) can successfully market its latest innovation to the Pentagon.

At this week's Society of Automotive Engineers World Congress being held here, TARDEC's National Automotive Center (NAC) is displaying the 4-passenger diesel-electric MP Hybrid concept, which is designed for non-tactical applications at medium speeds.

Its power source is a 6.7-hp (5-kW) diesel engine-generator that conveniently lifts out from under the hood and can power small electric devices, including air conditioners.

Diesel generator powers MP Hybrid and can be removed for stationary uses.

Joining the olive-green MP Hybrid military vehicle is a bright yellow topless “civilian” version devised from the same architecture.

Immediately after this week's show, the MP Hybrid and its civilian variant will undergo a month of rigorous testing in Camarillo, CA, and then be shipped to Alaska for further on/off-road driving, says Mike Kasaba, president of California Motors LLC, which built both prototypes and designed the chassis and drivetrain.

Until the testing is complete, Kasaba declines to estimate the hybrids' fuel economy, although he says the development target was to achieve 50 mpg (4.7 L/100 km). A conventional gas or diesel Humvee in military applications frequently achieves about 15 mpg (15 L/100 km).

TARDEC is interested in the MP Hybrid because it significantly reduces fuel consumption for non-tactical vehicles that operate away from battle zones. During wartime, fuel must be conserved to ensure uninterrupted supply for tactical vehicles in critical missions.

“The MP Hybrid enhances the capabilities of U.S. government vehicle fleets by providing a low-cost alternative for traditionally non-tactical operations,” says Dennis Wend, executive director of NAC.

Joining California Motors and NAC on the project is Quantum Fuel System Technologies Worldwide Inc., which will manufacture the hybrids in volume if a contract is signed.

“Working with Quantum Technologies and California Motors,” Wend says, “we've developed a technically advanced dual-use vehicle platform that will improve the effectiveness of agencies engaged in patrol and routine tasks, as well as counter-terrorism and interdiction operations along U.S. borders.”

The 4-wheel-drive MP Hybrid is a series hybrid. A removable generator powers a battery pack underneath the vehicle, and the batteries power two 10-hp (7.5-kW) electric motors that drive the wheels. Even with the two generators removed, the vehicle can run for a few hours solely on stored battery power, Wend says.

And Kasaba says the MP Hybrid, with its lightweight steel spaceframe and fiberglass body, is more than 60% lighter than a conventional Humvee.

Advanced Propulsion Technologies Inc., in conjunction with FEV Engine Technology, designed the lightweight generator, which is about the size of a large briefcase. Its four pistons - two in each cylinder - operate under the opposed-piston, lighter-cylinder principle. Wend says the generator will be ready for production in fall 2006. (See related story: FEV Shows High-Efficiency 2-Stroke Diesel)

The generator boasts five times the power density of conventional generators and five times greater specific power, with an engine that has 40% fewer parts compared with conventional 4-stroke engines, NAC says.

Its tank holds 2.5 gallons (9.5L) of diesel fuel, which it consumes at a rate of 420 g/kWh. The fuel would last about 3_ hours if the generator were running at 70% load, engineers say. A larger, supplemental tank onboard the vehicle ensures an adequate fuel supply beyond that of the generator itself.

The civilian version of the MP Hybrid is a parallel hybrid and also sports 4WD. A small diesel engine (0.78 L) that produces 18 hp drives the wheels, as does an electric motor in the rear of the vehicle.

With an eye on flexibility, the series hybrid powertrain of the MP Hybrid is completely interchangeable with the parallel hybrid powertrain of its civilian sibling.

Wend says the cost of the MP Hybrid approach will be attractive, although it is too early to attach a specific price tag.

“From a dollar-to-power ratio, this will be a very hard solution to beat anywhere in this country or the world,” he says. “We're trying to get high economy and fuel efficiency out of this and to bring down the cost. The performance is outstanding. Nobody can believe we're doing this with a diesel engine.”