| HYBRID TECHNOLOGY | ACTIVE FUEL MANAGEMENT (AFM) | BATTERY AND MOTORS | ||||||
At the heart of this innovative vehicle are traditional Sierra strengths, including a Vortec engine. In this case it’s the 6.0L V-8, using Variable Valve Timing (VVT) to produce 332 hp and 367 lb-ft of torque. Managing the on-the-fly blending of engine and electrical propulsion is an electronically variable automatic transmission. |
In situations where you don’t need extra power, such as cruising down the highway on level roads, Sierra Hybrid’s AFM deactivates four of the engine’s eight cylinders. When load demands increase, all cylinders are reactivated to provide eight-cylinder operation and maximum power. |
The electric portion of the hybrid system features a 300-volt nickelmetal hydride battery pack that fits neatly under Sierra’s rear seat without compromising passenger room or cargo space. When called on, two motors integrated within the transmission draw on battery power to propel the vehicle. |
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| STOP-TO-GO DRIVING | HYBRID MODE 1: KEY TO THE CITY |
HYBRID MODE 2: HIGHWAY / HAULING |
ENGINEERED FOR TRAILERING | |||||||
During normal stops, regenerative braking uses the motors in the hybrid transmission as generators to decelerate the vehicle by applying resistance in the motors rather than brake friction. At the same time, the motors are capturing that energy as electricity in the 300-volt battery pack, electricity that is available for the next acceleration cycle. |
At low speed and with a light load, Mode 1 can employ electric power alone, engine power alone or a combination of both. It reduces fuel consumption in stop-and-go traffic by shutting off the engine and operating on electric power alone. The result is an EPA-estimated 21 mpg in city driving, a 40-percent improvement over the traditional engine. |
At highway speeds, AFM uses either V-4 or V-8 operation—sometimes with supplemental electric power as conditions warrant. Full V-8 engine power is used when conditions demand it—such as passing, trailer towing or climbing steep grades. On the highway, Sierra Hybrid has an EPA-estimated 22 mpg. |
The Sierra Hybrid automatically and seamlessly selects the best operating point for the powertrain to deliver both fuel economy and performance while also reducing gear "hunting" associated with trailering. |
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