February 29, 2008

Innovation

Hybrid trucks gaining attention as new fleet option

KORKY KOROLUK

correspondent

OTTAWA

It’s big. It’s ugly. It has a unique electric drive train called ProPulse. And it could point the way for on and off-road hauling in the future. It’s called HEMTT A3, it’s ready for full production, and it’s about to enter service with the U.S. military.

Developed under a research and development grant from the U.S. defence department, the HEMTT (Heavy Expanded Mobility Tactical Truck) has a lot of features civilian operators wouldn’t be interested in, and a lot they would.

It carries a payload of 13 tonnes, for example, and can carry it up a 60 per cent grade. Its diesel-electric engine is economical to operate. And, if the terrain isn’t too uneven, it can cruise at 65 mph.

There is nothing unusual in converting technologies developed for the military to civilian use, so operators of heavy equipment are already watching the HEMTT.

Developer Oshkosh Truck Corp., of Oshkosh, Wis., developed the drive train, which it calls ProPulse, for several years.

In place of a standard drive train, the ProPulse diesel engine drives a generator which powers an electric motor on each of the vehicle’s eight wheels, which uses far less fuel than a conventional diesel drive.

Field trials have shown fuel savings on the order of 30 to 40 per cent.

The power pack is contained in a single module that can be removed and replaced in less than half an hour, and common axle and suspension modules reduce the need to stock replacement parts.

It has a built-in diagnostic system that allows the operator to monitor performance and to pinpoint emerging problem areas.

The vehicle can also function as an electrical power plant with a 120-kilowatt generator when parked. That’s because the military wanted it to be able not only to carry a complete field hospital, but to power that hospital as well.

The HEMTT is expected to have a 20-year life in military service.

With operators facing restrictions on exhaust emissions, with diesel prices rising, with the need for sustainable transport systems increasing month by month, civilian observers are enthusiastic at the possibility of transferring HEMTT technology to the civilian market.

“Hybrid trucks not only deliver goods and services, but also deliver environmental benefits that are critical to meeting energy needs,” said Stephen Johnson, administrator for the U.S. Environmental Protection Agency.

Elsewhere on the sustainable transport front: Volvo Group, the parent of Volvo Trucks, Mack Trucks and Volvo Construction Equipment, has delivered several hybrid trucks to the U.S. Air Force, including of couple of dump trucks built on the Mack Granite chassis. Other trucks delivered include a couple of heavy-duty refueling tenders for jet fuel.

All use something the company calls I-Sam, or Integrated Starter Alternator Motor, or simply an “electric machine.” It is an integrated starter, alternator and motor, and assists the Granite’s diesel engine in providing torque to the wheels. It also regenerates energy during braking.

The energy is stored in ultracapacitors, then used in place of diesel fuel to get the truck moving again.

Volvo claims fuel savings of up to 35 per cent.

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