will introduce the Chevy Tahoe and GMC Yukon models as hybrids
in 2008. Fuel economy improvements of at least 25% are
This will use
GM's new "two-mode" system. This system will be jointly used by
GM and Chrysler. The two companies hope that by working
together in developing this system, they will have a strong
competitive position in the hybrid market. The system is
referred to by GM as Advanced Hybrid System 2. While existing
hybrid designs offer their greatest fuel economy improvements
at low speeds, GM claims their design will be able to maximize
efficiency at highway speeds.
The system uses
two electric motors instead of one. One is used at speeds up
to about 40 mph, then the second motor comes into play. The
design is said to be particularly good at giving optimum power
for pulling a trailer.
focuses on first bringing out their larger models as hybrids
first. "We decided we would go after
hybrids attacking the highest fuel-consuming vehicles first
because that's where we could save the most petroleum," said
Tom Stephens, group vice president in charge of GM's
power train operations.
will have two 60 kW electric motors. The battery pack will
operate at 300 volts. GM will use displacement on demand to
enhance fuel economy. A few engine "tweaks" will be used,
including cam phasing, late-intake valve closure and a very
high compression ratio. The engine will be a Vortec V8. As a
point of comparison, the 2006 Tahoe with the 5.3 liter V8 and
4WD, is EPA rated at 15 city / 19 highway.
corrections Aug. 2007