Chevrolet Tahoe Hybrid delivers a dramatic improvement in fuel economy over non-hybrid models –33-percent in city driving – with the spaciousness and capability customers seek in a full-size SUV. It offers seating for up to eight and a towing capacity of up to 6,200 pounds (2,812 kg) on 2WD models.
The Tahoe Hybrid’s improved fuel economy over gasoline-only models is due largely to GM’s state-of-the-art two-mode hybrid system, which helps 2WD Tahoe Hybrid models deliver an estimated 20 mpg in the city. That’s comparable to the city fuel economy of many smaller cars.
Updates for 2012 include a new hard-drive navigation radio with a USB port, Time Shift Recording capability and more. StabiliTrak now incorporates trailer sway control and hill start assist. Two new exterior colors are offered, as well: Crystal Red Tintcoat and Silver Ice Metallic.
Also new for 2012 are seat-mounted side-impact air bags for the driver and right-front passenger.
Hybrid system details
GM’s advanced Electrically Variable Transmission (EVT) and 300-volt nickel-metal hydride Energy Storage System (ESS) work in concert with the standard 6.0L V-8 gasoline engine with Active Fuel Management (AFM) and late intake valve closing (LIVC) technology to enable the Tahoe Hybrid’s efficient performance. This hybrid system not only enables the Tahoe to launch and drive up to 30 mph on electricity alone, it also allows the 6.0L V-8 engine to operate in its more economical V-4 mode for longer periods.
GM designed the EVT to provide the best combination of city and highway fuel economy. Used with the Vortec 6.0L V-8 engine with Active Fuel Management, it is an all-purpose system well-suited to providing excellent economy and full-size SUV passenger-carrying, cargo-hauling and trailer-towing capabilities.
The EVT is designed to bolt directly to the standard four-wheel-drive transfer case found on the gasoline-only models for true four-wheel-drive capability. The following major components comprise the Tahoe Hybrid’s unique powertrain system:
- Electrically Variable Transmission (EVT)
- Energy Storage System (ESS)
- Vortec 6.0L V-8 with Active Fuel Management (AFM) and late intake valve closing (LIVC).
Electrically variable transmission (EVT): The key to GM’s EVT is its unique assemblage of two 60 kW electric motors, three planetary gearsets and four traditional hydraulic wet clutches. This arrangement allows continuously variable operation, and provides four fixed gear ratios (with operation comparable to that of a standard electronically controlled automatic transmission).
A sophisticated Hybrid Optimizing System constantly receives torque-based data from the powertrain and other vehicle systems, and then determines the most efficient means of propelling the vehicle — either via electric power, gasoline engine power or a combination of the two. The EVT is like having two transmissions in one — continuously variable drive for light-load conditions and fixed-ratio drive for high-load situations.
Energy storage system (ESS): A 300-volt nickel-metal hydride Energy Storage System (ESS) provides power to the EVT’s two electric motors. This battery pack is located under the second-row seat, where it takes up virtually no additional space and does not interfere with second- or third-row ingress/egress. The fold-and-tumble capability of the second-row seat remains, and flipping the seat forward provides a flat load floor from the liftgate forward to the front seats.
In addition to supplying power to the EVT, the ESS also provides power to the air conditioning compressor and the Accessory Power Module (APM), which converts the high-voltage supply to 42 volts for the electric power steering system, and 12 volts for the vehicle battery and other 12-volt electrical accessories.
Battery pack durability and reliability are maintained via optimized charge and discharge cycles, as well as a dedicated cooling system that draws air from the passenger compartment. As part of the vehicle’s emission control system, the ESS is warranted for eight years/100,000 miles.
Vortec 6.0L V-8 engine: Engineers chose the Vortec 6.0L V-8 gasoline engine for the Tahoe Hybrid because of its favorable torque characteristics. This is especially important because GM engineers adapted the 6.0L V-8 to operate with late intake valve closing (Atkinson-cycle combustion process) for reduced pumping losses and better overall fuel economy.
Using flat-top pistons, cylinder heads borrowed from GM’s 5.3L high-output V-8 and a 10.8:1 compression ratio, the Vortec 6.0L V-8 produces 332 horsepower (248 kW) at 5100 rpm and 367 lb.-ft. of torque (498 Nm) at 4100 rpm, yet requires only regular unleaded fuel.
The Vortec 6.0L also features continuously variable valve timing to control late intake closing, as well as Active Fuel Management, which allows four of the eight cylinders to be shut off during periods of light load. With the benefit of electric boost, the engine is able to stay in V-4 mode for longer periods in the Tahoe Hybrid.
Auto Stop mode and regenerative braking
A key contributor to fuel economy is the gasoline engine’s Auto Stop mode. At vehicle speeds between 0 and 30 mph, the gasoline engine may be automatically shut down. By leaving the engine off and allowing the vehicle to move only under electric power up to 30 mph, such as during heavy stop-and-go traffic, fuel consumption is greatly reduced.
The regenerative braking system works in concert with the hydraulic braking system. The system uses a brake pedal emulator, which provides progressive resistance as the pedal is depressed. This consistent pedal feel is very much like that of a standard hydraulic braking system in operation.
Peace and quiet
Tahoe Hybrid matches its gasoline-only siblings in comfort and convenience, with special attention paid to acoustic details that makes for a very quiet driving experience. Examples include:
- Exhaust system and resonator specially tuned for the 6.0L LIVC engine’s Active Fuel Management operation. It ensures comfortable interior acoustics and a pleasant exhaust note during both V-4 and V-8 operation
- Additional engine intake induction tuning for reduced interior noise and pleasing sound quality
- Low-rolling resistance, “quiet-tuned” P265/65R18 tires for reduced road noise
- Electrically driven, 300-volt air conditioning compressor reduces vibration and allows the HVAC system to cool the passenger compartment even when the gasoline engine is shut off
- Electrically driven, 42-volt variable-assist power steering reduces vibration and provides up to a 0.5-mpg fuel economy improvement by reducing parasitic losses common in belt-driven hydraulic systems
- Energy Storage System (ESS) cooling system internal fan is tuned to be quiet at low vehicle speeds when the fan could more easily be heard by the occupants.
Hybrid interior features
A unique hybrid gauge cluster includes a special tachometer incorporating an Auto Stop position just above the 0 rpm mark that indicates when the gasoline engine is in shut-down mode. An analog economy gauge, to the left of the tachometer, helps the driver maintain the most efficient driving style.
Located midway down the center stack, the standard navigation system’s 6.5-inch full-color VGA display doubles as a monitor that shows a graphic representation of the hybrid drivetrain’s power flow. This display continuously informs the occupants how the system is sending power to the wheels from the ESS/electric motors, the gasoline engine or both. The screen also displays reverse electrical flow during regenerative braking and whether the vehicle is in two- or four-wheel-drive mode.
While the Tahoe Hybrid bears a close resemblance to other models, styling revisions are made for aesthetic and functional purposes. In addition to setting these models apart from other SUVs, these exterior styling changes contribute to improved fuel economy:
- The front fascia lacks fog lamp and tow hook openings, while a lower air dam helps redirect airflow from underneath the vehicle to reduce turbulence and associated drag
- Subtle, yet important aero tuning details around the wheel openings and other areas contribute to a low 0.345 drag coefficient
- A slightly larger front grille opening allows increased airflow to the radiator and engine compartment, helping to cool the advanced hybrid power electronics
- The roof rack side rails have been eliminated to reduce drag and provide a clean, uninterrupted appearance
- Standard running boards have been tapered fore and aft, and incorporate body-color “spat” inserts for decreased wind resistance
- Extended D-pillar corner appliqués include sharper edges at the rear vertical corners for enhanced aerodynamic performance
- Specific rear fascia is aerodynamically optimized with sharper corners matching the extended D-pillars
- An extended rear spoiler (with integrated LED CHMSL) contributes to the vehicle’s overall aerodynamic performance
- Aerodynamically shaped rear brake lamps with LED lighting technology for reduced energy consumption.
Mass reduction inside and out
Mass is an important factor in overall vehicle efficiency. Because of the slight increase in curb weight resulting from the various hybrid components, engineers reduced the mass of numerous vehicle components, keeping the Tahoe Hybrid in the same test weight class as its gasoline-only counterparts.
On the outside, an aluminum hood and liftgate (with fixed glass) replace the standard steel units. Substituting an aluminum front bumper beam saved additional weight, as well as using low-mass, aero-efficient, 18-inch cast aluminum wheels.
Additional mass was eliminated by adapting a tire inflator kit that takes the place of the spare wheel and tire, hoist mechanism, jack and tools found on gasoline-only models. Easy to use, the tire inflator kit is conveniently located behind the left-rear quarter trim panel in the cargo area.
Tahoe Hybrid exterior features
- Hybrid model-specific front and rear fascias.
- Standard assist steps.
- Standard heated, power-operated outside mirrors including auto-dimming, integrated signal indicators, ground lights and curb-tilt feature.
- Eighteen-inch aluminum wheels and P265/65R18 all-season tires.
- Exterior color choices include: Black, Summit White, Crystal Red Tintcoat, Silver Ice Metallic, Black Granite Metallic and Mocha Steel Metallic.
Tahoe Hybrid interior standard and available features
- There are almost no exposed metal hardware or latches, as all models feature enclosing “close-outs” around the seat bottoms and door sill trim plates.
- Tahoe has the segment’s largest center console storage bin, a large glove box and numerous storage compartments.
- Three rows of seating are standard on all models. The second row is a three-passenger bench with a 60/40 split. The third row features a 50/50-split design and is removable.
- Leather-appointed and heated front seats are standard.
- Tri-zone automatic climate control is standard.
- SiriusXM Satellite Radio standard on all models.
- New hard-drive navigation radio with a seven-inch touch screen, USB port, Time Shift Recording capability, MP3 playback, navigation with voice recognition and color interface display.
- Bluetooth phone connectivity is standard.
- Power-adjustable pedals are standard.
- Sun, Entertainment and Destinations Package (PCJ) is optional and includes one year of SiriusXM Radio and NavTraffic service, power sunroof and rear-seat DVD entertainment system.
Tahoe Hybrid chassis and suspension
The Tahoe Hybrid is built on GM’s full-size SUV platform, incorporating a fully boxed frame, coil-over-shock front suspension, leaf-spring rear suspension and rack-and-pinion steering.
- Wide front and rear tracks – 68.2 inches (1,732 mm) front/67 inches (1,702 mm) rear – enhance handling and vehicle stability for a more confident road feel.
- A stiff frame reduces vibrations transmitted to the passenger cabin, while the strength and accuracy of the fully boxed frame also enable precise mounting and tuning of chassis and suspension components.
- A two-speed transfer case is standard on 4WD models.
- The standard axle ratio is 3.08.A locking rear differential is standard.
Tahoe safety and crash-avoidance features
- Standard head curtain side air bags with rollover protection for both seating rows. The roof-mounted head curtain air bags include design features that provide increased rollover protection and occupant containment.
- Standard seat-mounted side-impact air bags for driver and right-front passenger provide thorax and pelvic protection.
- StabiliTrak electronic stability control system helps reduce the risk of rollover crashes by keeping the vehicle in the driver’s intended path by applying throttle, braking or a combination of both.
- Standard Ultrasonic Rear Parking Assist that can detect certain stationary objects in the rearward path of the vehicle and send an audible warning sound and display via three LEDs near the rear window
- Standard rear vision camera system designed to provide the driver with
a view of people or objects in the rearward path of the vehicle.
- Standard four-wheel-disc brake system with ABS featuring smooth, quiet operation, longer pad life and more resistance to brake pulsation.
- Pretensioners minimize forward movement during a collision, and are standard on the front safety belts. Load-limiting retractors cinch the belt more tightly.
- LATCH (Lower Anchors and Tethers for CHildren) child seat attachment system, which is included in two second-row seating positions.
- Tire pressure monitoring system, standard on all models.
- Standard remote keyless entry (RKE) system provides a second function for the red panic button. Drivers can use it to locate their cars without sounding the panic alarm.
- Strong body structure to absorb crash energy and provide a protective “safety cage” around occupants.
OnStar is standard on the Tahoe Hybrid. It uses GPS and cellular phone technology to automatically call for help in the event of crash. OnStar subscribers also can use the service to be Good Samaritans by sending help to other motorists, and to call for help in other non-crash emergencies.
- OnStar is the leading provider of in-vehicle safety, security and information services in the United States and Canada.
- Six months of complimentary OnStar Directions and Connections service with Turn-by-Turn Navigation for easier route guidance on all Tahoe models. The feature is easy to use because all directions are sent to the car by an advisor, without the need to stop. Turn-by-Turn can be cost-effective, since map updates and aftermarket navigation systems are not needed.
- Stolen Vehicle Assistance helps police track the vehicle.