The U.S. Army has been successful
with field tests of the new version of its diesel-electric HEMTT (Heavy
Expanded Mobility Tactical Truck). Now it is proposing that the humvee
replacement use the same power system.
Army began introducing the humvees (or hummers) in 1984. This vehicle design,
the first new vehicle design since World War II (when the jeep and ¾ ton truck
was introduced), was expected to last for three decades or more. But that plan
changed once Iraq was invaded. As expected, hummers wore out a lot more quickly
(five years) in combat, than during peacetime use (14 years). So the army and
marines are developing, ahead of schedule, a new vehicle to supplement the
hummer in combat zones. Designs are being submitted, and the new vehicle is
expected to be selected, tested and enter production in five years. The army
will buy at least 38,000 of the JLTV (Joint Light Tactical Vehicle), while the
marines will buy about 14,000. The JLTV design using the diesel-electric drive,
has a roomier vehicle interior, because there is no drive train (each wheel has
its own electric motor.) This approach also makes it possible to install fuel
cells, which the military is also researching heavily.
The hummer will continue to be used outside of
the combat zone, where most troops spend most of their time. But the JLTV will
be built to better handle the beating vehicles take in the combat zone,
including a design that enables troops to quickly slide in armor and Kevlar
panels to make the vehicles bullet and blast proof.
proliferation of electronic and electrical equipment on the battlefield,
there's a growing power shortage out there. Thus the enthusiasm for the new
version of the 13 ton HEMTT. Here, the diesel engine drives a generator, which
produces over 100 kilowatts of power. Normally, this electricity runs electric
motors that move the truck. But put the truck in park, and the power is available
for other uses, like powering a military base in a remote location. Testing has
demonstrated that HEMTT A3 is rugged enough for regular army use, and gets
about the same fuel mileage as a diesel only system. A diesel-electric JLTV
would have the same advantages.
In 2005, a
HEMTT A3 prototype was sent to New Orleans, after Hurricane Katrina hit, and
provided power for a hospital. If this new "Propulse" technology
survives its remaining tests, it will be installed in other models of army
trucks as well. This gives the JLTV diesel electric design an edge in the
competition to select the model that will go into production, despite the fact
that diesel-electrics are 20-30 percent more expensive to manufacture.