At the heart of these trucks is a hybrid powertrain designed through a collaborative effort with BMW and DaimlerChrysler. In the Chevy, gas and electric propulsion systems come together to pump out more than 300 horsepower. The two-mode system is expected to improve fuel efficiency by up to 25 percent, and is relatively simple in its operation. The first mode operates at slow speeds and when the Tahoe is carrying light loads, with power being supplied by either a compact electric motor, the Vortec V8 gas engine, or a combination of the two. Like full hybrids on the market today, the 2008 Chevrolet Tahoe Two-Mode Hybrid can creep along at slow speeds under pure electric power, and shuts off the engine what resting at idle. The second mode doesn’t really fit under the definition of hybrid, as it uses GM’s Active Fuel Management displacement on demand technology, variable valve timing, and specific engine controls to conserve fuel.
Aside from what’s under the hood, the Tahoe Two-Mode Hybrid (as well as the GMC Yukon and Cadillac Escalade versions) wears lightweight aluminum wheels rolling on low-resistance tires, features a more aerodynamic front fascia, and swaps in aluminum body panels to save weight. There’s no word yet on production levels or pricing, but like most hybrids, there might be a challenge in justifying the added expense versus real-world fuel economy gains.
Photos by Ron Perry