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With surging fuel prices military forces are re-examining the
potential savings of alternative propulsion, hybrid cars and trucks
are becoming a reality in the commercial market. "Hybrid-Electric
Drive" (HED) systems are promising up to 30 – 40 percent savings, compared to
current internal-combustion engines. Typical Hybrid-Electric Drive (HED) systems store regenerative power when braking and using it for
acceleration and off-road maneuvering, to augment the main engine. By
electronically controlling each wheel, HED systems dynamically manage
the drive torque going to each wheel; accommodating any driving
condition on and off-road. While HED systems have great benefits in
fuel economy, improved performance and weight saving, hybrid cars
still challenge users with expensive systems, primarily battery costs
and sensitivity due to environmental effects.
The US Army expects hybrid-electric powered trucks and the hybrid-electric
Future Combat Systems (FCS) to help the service attain its stated
objective of 75 percent lower fuel consumption by 2020. Significant
savings have already been demonstrated. Operating as a hybrid, with a
24-gallon tank, a truck could travel 375 miles without refueling
compared to a conventionally-powered vehicle, traveling less than 60%
of that range. Savings will not relate from the cost of fuel itself,
but trim a considerable volume off the army logistical transportation
requirements – as fuel takes up about 70 percent of the logistical
tonnage haul in a heavy armored division.
When used in combat vehicles, hybrid-electric drives have even more
benefits. The acoustic signature can be reduced by moving on
electrical power with main engine shut off and the placement of engine
exhaust below the vehicle, to minimizing noise signature when the
engine is running. Thermal signature is reduced by burying the hot
mufflers and manifolds deeper in the vehicle to reduce infrared
signatures. When used for logistical support, hybrid electric vehicles
can generate enough “exportable” power to run most field equipment
currently used by the military.
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