Here's some news we weren't expecting. The 2008 Saturn Vue Green Line Hybrid will sport the first front-wheel drive version of the company's two-mode hybrid system first seen on the Chevy Tahoe Hybrid. The full hybrid drivetrain should return a 45-percent improvement in fuel economy over a non-hybrid Vue. That's a big bump over the 25-percent improvement in fuel economy that GM's claiming for vehicles saddled with its mild hybrid drivetrain, like the current Vue Green Line and upcoming 2008 Aura Green Line. The main difference between the two types of hybrid drivetrains is that the two-mode system allows for electric-only propulsion at low speeds while the mild system's battery backs can only assist the gas engine.
The Saturn Vue Green Line's transmission also sounds like a piece of trick hardware, with two electric continously variable modes and four fixed mechanical gear ratios. While details are scarce and we left our engineering degree back home, that tranny appears to be a combination of a CVT and traditional four-speed that's split between the electric drive and power provided by the gas engine, which is GM's own 3.6-liter VVT V6. Perhaps we're reading the press release wrong, but it's light on verbage and exposition so that's all we have to go on.
It's a very smart move by General Motors to upgrade the Vue Green Line to true hybrid status, especially considering that an even more frugal Vue Green Line Plug-In Hybrid is now being developed. While most shoppers aren't aware of the intricate differences between a mild and full hybrid setup, the cache that comes with running a full hybrid drivetrain has weight and the improvement in mileage can't be denied. The fact this is the first front-wheel drive application of GM's two-mode hybrid system means we should see it start being used in other passenger cars in the near future, as well.
Check out the full press release for yourself after the jump.
Front-Wheel-Drive, 2-Mode Hybrid System Debuts in 2008
Saturn Hybrid SUV Expected to Offer Up To 45-Percent Fuel Economy Improvement
LOS ANGELES – General Motors Corp. will expand the industry's most diverse portfolio of hybrid technologies in 2008 with the debut of its front-wheel-drive, 2-mode hybrid system in the Saturn Vue Green Line SUV, the automaker announced at the Greater Los Angeles Auto Show.
By using this sophisticated hybrid technology, the Vue Green Line 2-mode Hybrid is expected to deliver up to a 45-percent improvement in combined city and highway fuel economy compared with the non-hybrid Vue, based on current federal test procedures.
"We are delivering on our promise to continue our steady rollout of additional hybrid applications, each offering different levels of affordability, fuel savings and performance," said Tom Stephens, GM group vice president, GM Powertrain. "This will be the auto industry's first front-wheel-drive vehicle to use a 2-mode hybrid system, which improves fuel economy while maintaining performance and capability."
The Vue Green Line 2-mode Hybrid SUV will be powered by GM's 3.6L V-6 gas engine, with direct injection and variable valve timing, a nickel-metal hydride battery pack and two active cooled permanent magnet motors.
The front-wheel-drive, 2-mode hybrid system optimizes city and highway fuel efficiency by integrating two electric continuously variable modes with four fixed mechanical gear ratios.
This design is similar to the 2-mode hybrid system for rear-wheel-drive applications, which will debut next year in the Chevrolet Tahoe and GMC Yukon full-size SUVs.
The 2-mode hybrid system improves fuel economy by the following operations:
- Engine off at idle
- Low speed electric-only propulsion
- Electric boosting during brisk acceleration, climbing steep grades or towing
- Cutting off fuel to the engine during vehicle deceleration
- Regenerative braking
- Engine speed and load control
- "The 2-mode hybrid system has the flexibility to improve fuel efficiency across a range of vehicles," Stephens said. "For example, in 2003, we introduced the 2-mode hybrid system for transit buses. In 2007, the Chevrolet Tahoe and GMC Yukon 2-mode full-size SUVs will debut, followed by the Vue Green Line 2-mode in 2008."
By using two electric modes and four fixed gear ratios, the 2-mode hybrid system's electric motors are smaller, compared with traditional "one-mode" hybrid systems, and impose no significant limitation on the size of the engine.
Consequently, the 2-mode hybrid system fits into the same space as a conventional automatic transmission, minimizing packaging, cost and weight issues. The result is exciting performance and outstanding fuel economy.