V7 Sierra and Yukon offer a balance of fuel economy and performance

With Active Fuel Management, GM drivers get the power they need on demand

It takes a powerful engine to tow a trailer of 10,000 pounds or carrying a load of nearly 2,000 lb, but when there is nothing to carry the Active Fuel Management helps the driver to travel further with each liter of gasoline.

Thanks to the more active fuel management, V8 engines of Sierra pickups and SUVs GMC Yukon can operate in four-cylinder mode when the load is low and if the speed is constant, but are always ready to go at full power desired. The concept of variable cylinder engines initially been imagined by engineers, but the technology has really developed with the arrival of new electronic engine management systems and sequential injection.

When the truck is not supported and that only a fraction of the engine power is requested to maintain a constant vehicle speed, the power of four of the eight cylinders is cut and tappets are debase by a solenoid valve system to reduce losses at the pump and improve energy efficiency. Of the vehicle to climb an incline or the driver presses the accelerator, these cylinders are reactivated almost imperceptible ways.

For hybrid models Sierra and GMC Yukon, the engineers have used the system bimodal peak to assist the engine at highway speeds, which allows the Vortec 6.0L V8 to remain in four-cylinder mode longer. While an ordinary variable cylinder engine should switch back to eight cylinders to climb a slope, hybrid models use their electric motors to maintain the speed of the vehicle while remaining in four-cylinder mode. These trucks can barely eat and 10.1 L/100 km city and 8.4 L/100 km on the highway.

With a consumption of 13.7 L/100 km city and 9.1 L/100 km on the highway, GMC Sierra XFE 2011 with Active Fuel Management is the pick-up full size V8 most thrifty fuel in America. Active Fuel Management is also offered with the Sierra and Yukon equipped with a V8 engine of 5.3; 6.0 or 6.2 l, even with several pickups and SUVs e Chevrolet Cadillac and Chevrolet.

"With Active Fuel Management, Sierra and Yukon offer all the expected from a truck or a full-size SUV while reducing fuel consumption, performance," said Jordan Lee, chief engineer and director of international program a compact block engines.