2005 GMC Graphyte Concept

In many ways, the Graphyte is the 'yang' to the Astra Concept's 'ying,' its diametric opposite; the Graphyte is a large sport

The Two-Mode hybrid system can be adapted to a broad range of vehicles. (Photo: Trevor Hofmann, Canadian Auto Press)

ute capable of traversing off the path, while the Astra is a road-bound, compact three-door hatchback.

Its main form of power is provided by cubic inches and pushrods, whereas the Opel utilizes the most advanced common-rail turbodiesel technology. The Graphyte is all- wheel drive, while the Astra is propelled by its front wheels. But most importantly, the vast differences in the concepts help emphasize one main point: the Two-Mode hybrid system can be adapted to a broad range of vehicles.

Like its name suggests, the Two-Mode hybrid drive system features just that - two modes. The first one provides fuel-saving capabilities when traveling in low-speed and stop-and-go driving. Full-electric power, or a

Reportedly, the Graphyte posts a fuel consumption rating approximately 25 percent lower than an equivalent-sized gas-powered SUV. (Photo: Trevor Hofmann, Canadian Auto Press)

combination of electric and gasoline power, is used in these situations, allowing the Graphyte to post a fuel consumption rating approximately 25 percent lower than an equivalent-sized gas-powered SUV.

The Graphyte's second mode is full-gasoline power, which is used at higher speeds, and in heavy-demand situations such as towing, off-roading or climbing steep gradients. The Graphyte's muscular Vortec 5300 V8 with 300 horsepower and 325 lb-ft of torque provides the kind of force which owners of large SUVs need, but it also has Displacement On Demand (DOD) technology which shuts off half the cylinders in low- load situations to improve fuel consumption.