Quick Drive: Buick/Saturn Vue plug-in hybrid prototype

Saturn Vue plug-in hybrid prototype - click above for high-res image gallery

We had a chance for a quick drive of a development prototype for Buick's upcoming plug-in hybrid crossover this week at the GM proving ground. The prototype was still wearing its Saturn grille and badging as that was the original intent of the program. When Rick Wagoner announced in late 2006 that the company would develop a plug-in hybrid, it was intended to the be the Vue. Of course, at that time, Saturn still had a future as part of GM but we all know how that turned out.

The Vue was Saturn's best-selling vehicle in 2008 with nearly 82,000 units sold. For the new version, the silly fake fender vents are being dispensed with and a water-fall grille is being applied to make it a Buick (so much Fritz Henderson's hatred of re-badging). The two-mode hybrid system that was scheduled to go into production late last year lives on but is now paired with an 8 kWh lithium ion battery pack supplied by LG Chem. According to Larry Nitz, director of hybrid powertrain development, this is half of a Volt pack repackaged to fit under the rear cargo floor. Learn more after the jump.

[Source: General Motors]
Photos Copyright ©2009 Sam Abuelsamid / Weblogs, Inc.

Earlier in the day, we had seen the Buick version in the design studio at the Warren technical center. On the outside, little has changed. However, under the skin, the delays to the program have given GM the opportunity to make a number of updates. The same 3.6-liter direct injected V6 that was to go into the Vue is retained but it will now have flex-fuel capability. This wlll be the first direct injected V6 so equipped. According to Nitz, the decision was made to stick with the larger V6 instead of one of the new smaller engines GM has launched this year in order to retain the towing and acceleration capability for a premium vehicle. Future PHEVs from GM will likely go to smaller displacement engines.

The new PHEV also benefits from the Volt program with a new power inverter. The Volt inverter is smaller, lighter and more efficient than the unit originally developed for the two-mode Vue. The battery management system is also common to the ER-EV and will include conditioning of the battery to the optimum temperature range when it is plugged in. Nitz confirms that the PHEV could be driven around at low speeds (below about 30 miles) for over ten miles on battery power alone. However, it is not really designed for that.

As a blended system (like other parallel hybrids) the PHEV, is optimized to discharge the battery when it is most efficient to do so while using the engine when it makes more sense. It will be able to cruise along at about 40 mph with the engine switched off, just like an Escape, but the acceleration and towing capabilities are significantly better. In what is expected to be typical use, the pack should be fully discharged within about 20 miles of driving.

The powertrain engineers have made significant progress on learning to control the hybrid interactions of the front drive two-mode system since I last sampled it. (disclosure: in my previous life, I worked on the brake control system for the two-mode Vue among many other projects) The transitions between engine on and off are now as seamless as the latest Ford hybrids which are among the best on the road. Driving around the city course I had to glance down at the power flow display to see if the engine was running. Acceleration response was always good and the vehicle never left me waiting.

The Buick will have charge ports under the front fender badges that will replace the fake fender vents used on the Vue. The conventionally-powered Buick will launch later in 2010 with the 2.4-liter four and 3.0-liter V6 direct injected engines. The plug-in hybrid will launch in 2011, about a year before Ford launches its own PHEV and Toyota is expected to start retail sales of the PHEV Prius.

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