Car Evolution: 2008 NAIAS: 2009 Saturn Vue Green Line 2 Mode Hybrid

How the Vue Green Line 2 Mode Hybrid works

GM�s two-mode hybrid system in the Vue Green Line 2 Mode improves fuel economy by the following operations:

Engine off at idle
Low-speed, electric-only propulsion
Cutting off fuel to the engine during vehicle deceleration
Regenerative braking
Energy-efficient accessory systems

Unlike single-mode hybrid technology found in competitors� SUVs, the two-mode system maximizes city and highway fuel economy by integrating two electric continuously variable modes with four fixed mechanical gear ratios. The system consists of twin, active-cooled 55-kW electric motors integrated into the 2MT70 automatic transmission. Energy to power the motors comes from a 1.8 kWh, 300V nickel-metal hydride battery pack, which consists of 22 nickel metal hydride modules and is packaged behind the second-row seat below the cargo floor.

The transmission is mated to GM�s 3.6L V-6 VVT with direct injection technology. In the first mode, at low speed and light load, the Vue Green Line 2 Mode operates in one of three ways depending on conditions and battery charge level: all-electric power, internal combustion engine power or a combination of the two. All reverse operation is driven by the electric motors.

The second mode is used primarily at highway speeds to optimize fuel economy. It provides electric assist in addition to six-cylinder power when conditions demand it, such as trailer towing and climbing steep grades, and to allow the engine to run at its most efficient point under less-demanding conditions.

No engine speed changes are necessary for the mode shift to occur. The result is exceptionally smooth, seamless acceleration and responsiveness. At all times, the system�s Hybrid Optimizing System (HOS) collects torque-based data, deciphers it, then determines the most fuel-efficient means of propelling the Vue Green Line 2 Mode.

Direct injection V-6 boosts efficiency

The Vue Green Line 2 Mode�s standard engine is an advanced 3.6L V-6 VVT with direct injection, a member of GM�s family of high-feature V-6s. The direct injection engine uses regular unleaded fuel and represents one of the most sophisticated applications of its kind on a hybrid SUV.

Direct injection delivers fuel directly to the combustion chambers and permits a higher compression ratio, improving fuel efficiency. Additionally, the technology reduces cold-start hydrocarbon emissions by up to 25 percent.

The 3.6L VVT with direct injection also features a U.S. auto industry-first isolated fuel injector that greatly reduces the ticking noise associated with other direct injection engines. Other noise-reduction features include the use of acoustic foam in the engine valley and cover.

Specially tuned chassis for a smooth ride

Because the hybrid system changes the weight distribution on the Vue Green Line 2 Mode, special chassis refinements such as revised front and rear spring rates; revised front and rear stabilizer bar rates and recalibrated front struts and rear shock absorbers help ensure a smooth driving experience.

The Vue Green Line 2 Mode is equipped with a �fully blended� electro-hydraulic brake system that enables 100-percent regenerative braking (batteries are charged during braking), 100-percent friction braking (traditional four-wheel disc braking) or a combination of the two. During regenerative braking, the system converts kinetic energy to electrical power, then stores the power in the Energy Storage System.

A 12V rack-mounted Electric Power Steering system replaces a conventional column-mounted hydraulic system and saves fuel � gaining up to a half-mile per gallon of gas. It also gives the Vue Green Line 2 Mode more precise steering inputs and better overall on-center feel.

Intuitive displays keep drivers in the know

The Saturn Vue Green Line 2 Mode�s instrument panel lets drivers know that they�re behind the wheel of a sophisticated hybrid, yet with gauges that are easy to understand. An efficiency gauge replaces the tachometer, informing drivers of when they are achieving maximum fuel economy; whether the vehicle is in electric-only mode, engine-only mode or a combination of the two; and, because of the silent start as the key is turned, a telltale indicates when the vehicle is on and ready to drive.

In the center console, a full-color VGA power-flow graphic, which is integrated into an available navigation system, continuously informs the driver and passenger whether the vehicle is sending power to the wheels from the battery pack, engine or both. It also indicates when energy is being captured during braking.

Vue Green Line 2 Mode is generously equipped

In addition to its high-tech propulsion system, the Saturn Vue Green Line 2 Mode boasts a number of standard safety features including four-wheel anti-lock brakes, electronic stability control, rollover detection system, pedestrian impact protection, tire pressure monitoring system, Pedal Release System, front active head restraints, and six air bags (driver and front passenger frontal and seat-mounted side-impact, and roof rail curtains for both seating rows).

Other features include power-adjustable heated outside mirrors, leather-wrapped steering wheel with integrated audio and cruise controls; and a six-speaker AM/FM stereo with CD/MP3 player and auxiliary input jack. A navigation system and power sunroof are available.

Saturn�s hybrid family is growing

The Vue Green Line 2 Mode is the third hybrid to join the Saturn lineup. Other members of the Green Line family include the Vue (4-cylinder) Green Line and the Aura Green Line sedan. They are equipped with the affordable GM Hybrid system, which reduces fuel consumption using sophisticated controls and a unique electric motor/generator mated to a 2.4L Ecotec VVT four-cylinder engine and Hydra-Matic four-speed transmission.