General Motors Corp. will take the wraps off the ’09 Saturn Vue Green Line 2-mode hybrid cross/utility vehicle at the North American International Auto Show in Detroit next week.

The auto maker expects the system to provide a combined city/highway fuel-economy improvement of up to 50% over the ’08 Saturn Vue with a 6-cyl. engine.

According to the Environmental Protection Agency, an ’08 Saturn Vue equipped with a gasoline V-6 achieves a combined 19 mpg (12.4 L/100 km).

GM anticipates the system will provide the greatest improvement in city driving, up to 65% over the traditionally powered Vue, which the EPA rates at 16 mpg (14.7 L/100 km).

The existing ’08 Saturn Vue Green Line, which mates an electric motor/generator to a 2.4L 4-cyl. engine to achieve a combined fuel-economy rating of 28 mpg (8.4 L/100 km), will sell alongside the 2-mode version when it arrives at dealers next year.

The vehicles will sell at different price points with a premium on the 2-mode variant.

Slated for production in late 2008, the CUV marks the first front-wheel-drive application of GM’s 2-mode hybrid system.

GM already makes the system available on its Chevrolet Tahoe and GMC Yukon fullsize SUVs, and this spring it arrives on the Cadillac Escalade SUV. The Chevy Silverado and GMC Sierra fullsize pickups receive the option in late-2008.

The system combines an internal combustion engine with a nickel-metal hydride-battery pack to improve fuel economy. The 2-mode Vue Green Line unites a 300-volt battery pack with a 3.6L V-6 engine optimized by variable-valve timing and direct injection. A pair of active-cooled 55-kW (73-hp) electric motors integrated into the vehicle’s automatic transmission assist propulsion.

At low speeds the 2-mode Vue Green Line operates under electric-only propulsion. Fuel economy also benefits from an engine-off at idle feature, fuel cut-off during deceleration, regenerative braking and energy-efficient accessory systems.

But Saturn officials say the 2-mode Vue Green Line will not sacrifice power for the improved fuel economy. Although horsepower and torque numbers have not been released, current estimates call for a 0-60 mph (97 km/h) time of about 7.3 seconds and a maximum towing load of 3,500 lbs. (1,588 kg).

“The Saturn Vue Green Line 2-mode challenges the notion that a compact SUV can’t be both powerful and efficient,” Saturn General Manager Jill Lajdziak says in a statement.

Unique “2-Mode” badging will distinguish the vehicle from its standard stablemate.