Chevrolet promises that its 2008 Tahoe Hybrid will boost its lead as the most fuel-efficient large SUV on the market. The 2-Mode Hybrid, Chevrolet says, will deliver 21 mpg in city driving, a boost of 50 percent over the standard Tahoe with a gas-only 5.3-liter V-8. In highway driving the Tahoe Hybrid will get 30-percent better fuel economy than the conventional Tahoe, GM says.

The Tahoe Hybrid is being shown at the 2007 Los Angeles auto show, alongside the Dodge Durango and Chrysler Aspen hybrids, which also feature a two-mode hybrid system engineered in a joint venture between General Motors, Chrysler, Daimler, and BMW. The Tahoe Hybrid’s dual action is actually a series of different driving modes programmed between its transmission, engine, and battery pack and motors. In the first mode, the Tahoe can run on either its electric power or its gasoline power or both.

In mode two, the Tahoe uses electric power as an assist to its V-8 engine - in passing, towing, and climbing, for example. The engine is also outfitted with cylinder deactivation technology, which operates in the second mode to help dampen fuel consumption. The two-mode system is expected to make its way into most of GM’s full-size truck lineup, but the basic idea is scalable to vehicles of most any size, GM says.

With the two-mode system the Tahoe still delivers a maximum tow rating of 6200 pounds and eight-passenger seating. Its stock body is largely intact, though Hybrid models are about a third of an inch lower in ride height. The hood and tailgate are made of aluminum to save weight. And the Tahoe’s body has been tweaked to allow for better aerodynamics. Related Articles 2007 Los Angeles Auto Show Coverage by TCC Team (11/9/2007) Mustang Bullitt, Lincoln MKS, Durango Hybrid and Genesis coupe.