General Motors will offer optional hybrid powertrains on several of its most popular models — including trucks, SUVs and mid-size sedans — starting in late 2003, said GM President and CEO Rick Wagoner.
"This is a major commitment to offer consumers three different hybrid propulsion systems on three vehicle architectures, representing more than a dozen of our most popular models," Wagoner said. "Although today's hybrid market represents relatively low volumes, we're well positioned to meet market demand as it develops. In fact, if consumers were to select the hybrid option on all of the models included in our multi-year plan, it could eventually exceed 1 million vehicles.
"Because hybrids cost several thousands of dollars more than conventional vehicles, we believe offering multiple approaches on our most popular vehicles is the best way to explore the market for the technology," Wagoner added. "Consumer-based tax credits will play a critical role in gaining market acceptance by making these technologies more affordable."
The systems vary in complexity and cost to explore the market viability of each application. The models start with the already announced production of the GMC Sierra and Chevy Silverado hybrid pickup trucks in 2003. The new programs include:
Starting in 2005, GM will begin production of a Saturn VUE featuring a dual electric motor system that will boost composite city/highway efficiency up to 50 percent to nearly 40 mpg. A highly sophisticated system, featuring the most advanced components and control electronics, the VUE hybrid was designed to maximize efficiency with strong performance.
GM will also include a hybrid option for the Chevrolet Equinox starting in 2006, which mates electric motor assist to GM's VTi variable transmission to the highly efficient Ecotec four-cylinder engine. The combination of VTi with electric motor assist is a sensible approach that provides a fuel economy increase of nearly 15 percent on one of GM's smaller vehicle architectures. GM will also offer the same hybrid system in its Chevrolet Malibu sedan, with production scheduled for 2007. If successful, the system could be readily available on other mid-size models as demand warrants.
In addition to the pickups, which start production in 2003 for fleet customers (retail consumers will be able to purchase the vehicles in 2004), GM will offer in 2007 a revised version of this system that adds GM's Displacement on Demand technology which will be made available on the next generation of GM's popular full-size SUVs, including the GMC Yukon and Chevrolet Tahoe. This combination boosts fuel economy by 15-20 percent.
Hybrids draw power from two different energy sources, typically a gas or diesel engine combined with an electric motor. GM's approach stretches from the very aggressive with the dual electric motor VUE, to the more practical approach of combining electric motor assist with other efficiency gaining technologies such as Displacement on Demand and VTi.
Displacement on Demand saves fuel by using only half of the engine's cylinders during certain driving conditions. The system automatically and seamlessly reactivates the other cylinders when the driver needs the engine's full capabilities for brisk acceleration or load carrying. In stop-and-go driving, where fuel efficiency is at its lowest, an electric motor assist enables smooth automatic engine shutoffs and restarts at idle, early lockup of the torque converter clutch in second gear, and aggressive fuel cutoff and regenerative braking while coasting and accelerating. This combination provides a practical and effective hybrid that is well suited to North American driving patterns in GM's trucks and SUVs. The same is true with VTi transmissions to be utilized on the Equinox and Malibu. VTi variable transmissions automatically operate at an infinite number of gear ratios over a wide overall ratio range, helping to keep the engine operating near its best efficiency under all driving conditions.
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Written by: Car and Driver
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