GMC Graphyte

The GMC Graphyte "crossover" is a boldly styled, large-wheeled concept vehicle in the old tradition. It exists mainly to call attention to one of GM's alternative-fuel promises, the "two-mode full hybrid" drivetrain developed in partnership with DaimlerChrysler.The news here is that this system will be a full hybrid, meaning it can run on electric power alone, gasoline power alone or a combination of the two, for a claimed 25 percent fuel-efficiency improvement over conventional gasoline vehicles.GM's only current hybrid system, aside from a diesel-electric drivetrain for mass-transit buses, is available in the Chevrolet Silverado and GMC Sierra. Calling these vehicles hybrids, as GM does, is a bit of a stretch. The electric motor doesn't propel or aid in propelling the vehicle at all. It is basically an integrated starter/generator that automatically starts and stops the V-8 engine for minimal fuel savings when stationary.Conversely, the two-mode system, which will combine two more-robust electric motors and a 300-watt battery pack with the 5.3-liter V-8, should emulate the hybrid drivetrains in Toyota vehicles and the Ford Escape Hybrid. These models achieve the highest fuel-efficiency savings among current hybrids.GM entered the joint venture with DaimlerChrysler to share engineering expertise, achieve cost efficiencies and speed development. GM says the technology will have applications across all brands and vehicle sizes, beginning with 2007-model full-size sport utility vehicles. DaimlerChrysler will use the technology both in Chrysler Group and Mercedes-Benz vehicles.

source : cars