Normally the vehicle — a Heavy Expanded Mobility Technical Truck or HEMTT — would be so loud the occupants wouldn’t be able to talk to each other, said Schmiedel, vice president of product engineering for Oshkosh Truck Corp. But this version is about as loud as a standard sedan, with a smooth ride, splashy computer screens and a comfortable interior.
This isn’t your dad’s military truck, a bumpy, loud gas guzzler. This is a hybrid made at the request of the Defense Department.
Oshkosh Truck, the military’s exclusive provider of the Army’s heavy cargo-hauling HEMTT vehicles, is finishing up prototypes of its electric hybrid. It not only increases gas mileage by about 20 percent from the standard 3 to 4 miles per gallon, it generates enough electricity to power a city block or hospital. The company, based in this city about 100 miles north of Milwaukee, just signed a contract to produce a prototype of a similar vehicle for the Marines.
The hybrid technology can be far-reaching, said Schmiedel. Commercial vehicles such as garbage trucks and emergency vehicles all could benefit from using less fuel, he said. The Department of Energy has said it hopes to double the fuel economy of garbage trucks by 2010.
The ability to generate power could be another selling point, Schmiedel said. The technology has a storage system capturing energy that would otherwise be wasted in the braking process. The generator can produce up to 300 kilowatts of power — enough to run 50 homes for an indefinite amount of time, he said. In response to Hurricane Katrina, Oshkosh took a hybrid truck to New Orleans and used it to pump out a hospital basement.
While manufacturers such as Honda and Nissan have said they’re considering slowing down production of hybrid vehicles due to sluggish sales, development of the technology for military and commercial use doesn’t seem to be waning, Schmiedel said.
Schmiedel and others at Oshkosh have been working since 1999 on the technology, called ProPulse. The company has made two trucks. It plans to make a few more and turn them over early next year for government testing, a process that could take a year, he said.
Though hybrid technology has been around for several years in passenger vehicles, adapting it for larger vehicles isn’t as easy, Schmiedel said. Military vehicles must often carry thousands of pounds of cargo — 13 tons for the HEMTT — and endure hills, little pavement and angles that few standard vehicles can handle. That all means engines and axles must be configured just so.
In the case of the newest version — called the HEMTT A3 — a diesel engine powers a generator that sends power to electric drive axles. Energy is stored when trucks coast or decelerate. The motor turns into a generator and provides power back into the vehicle, which can be used for the next acceleration or later to power outside sources.
Oshkosh Truck, which saw nearly $3 billion in sales last year, has made nearly 20,000 HEMTTS, with an estimated 2,500 in use in Iraq. One-third of the company’s sales come from the military. The company also makes tow trucks, garbage trucks, concrete mixers and fire trucks.