From Dale Wickell,
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GM's new diesel hybrid military truck, equipped with a fuel cell auxiliary power unit (APU), is what the company hopes will be the model for the 30,000 new trucks that will enter the Army's fleet of light tactical vehicles by the end of the decade.

The fuel cell APU would replace the stationary generators the Army currently uses for field power. Fuel cells are quieter than engine generators and don't give off as much heat, so they aren't as likely to be picked up by the enemy's heat sensors.

A militarized version of the Chevy Silverado crew cab, the truck has a 20 percent better fuel efficiency than conventional diesels. It provides troops with clean, reliable electrical power.

"The potential for fuel cell and diesel hybrid technologies are of critical importance for the Army's next generation of tactical vehicles, and General Motors will play a key leadership role in the research and development efforts for transforming the Army's mobility," Dennis J. Wend told reporters. Mr. Wend is the director of the National Automotive Center, coordinator of the US Army's collaborative vehicle research and development.

He continued, "In order for the Army to win today's and tomorrow's battles decisively, we must transform to a lighter, more mobile, more fuel-efficient Army, an Army that is rapidly deployed and sustainable anywhere in the world. The fuel cell auxiliary power unit's quiet operation and low heat signature also are vital elements in reducing the visibility of a deployed force."

The truck's military features include:

• Raytheon First Responder command and control equipment, infrared night vision camera and GM's "extreme mobility package" to meet harsh off-road conditions and payload requirements.

• A 6.6-liter Duramax Diesel V-8 engine, which generates 210 horsepower and 545 lbs.-ft. of torque.

• A diesel-electric hybrid powertrain that can operate as a self-contained generator, with the capability of providing up to 30kw "exportable" DC and AC electricity for troop operations in the field.

• A fuel cell APU that is a 5-kilowatt proton exchange membrane (PEM) regenerative fuel cell system. It is capable of producing electricity and hydrogen in remote areas.

When the vehicle is driven, the PEM electrolyzer uses diesel engine provided electricity to break down water into hydrogen and oxygen, with the hydrogen stored for future use. Later, with the engine off, the stored hydrogen, together with oxygen from the air, is fed to the fuel cell to produce electricity, returning the pure water as a byproduct, which is stored to repeat the cycle.

The regenerative APU thus produces its own hydrogen and the Army does not need to add a new logistics fuel. Any additional water is not a problem since water is already provided to the troops and, in a difficult situation, the fuel cell-produced water is drinkable.

Fuel Cell Auxiliary Power Unit
The diesel hybrid truck is one of eight different militarized prototypes based on the Silverado that GM Defense will deliver to the Army as part of the Commercially Based Tactical Truck (COMBATT) program. The program leverages commercial technology to reduce the cost of developing and acquiring a light tactical vehicle, and provides the Army with continuous technology improvement.

The Army is evaluating the prototype truck before establishing performance criteria and opening the bid process.

Source: GM Press Release, 1/09/03
Photos Copyright GM