Cylinder switch off delivers advantages to Chevy Silverado

(August 17, 2012) DETROIT — Full-size pickups are unique, both in the jobs their owners ask of them and how long customers expect them to last. So for the Chevrolet Silverado and other full-size trucks, General Motors improves the fuel efficiency of its mainstream 5.3-liter V-8 engine by switching off four of the cylinders when they aren’t needed.

More than 85 percent of Silverado customers use their pickups to tow or haul. Some truly put their trucks to the test, moving large trailers over long distances, such as in the blistering heat of west Texas and the biting cold of Alaska’s Prudhoe Bay. These customers expect their trucks to be economical and they expect them to last. 

And more than half of all full-size Chevy pickups sold 20 years ago are still on the road.

The Silverado has a well-earned reputation as the most-dependable, longest-lasting full-size pickup. The V-8 engines under the hood have a track record no competitor can touch – developed, tested and refined over 57 years and more than 100 million engines.

Engineers developing the current Silverado sought the most intelligent solution for improving the fuel economy while preserving performance and durability.

“Rather than adding turbochargers or multi-valve cylinder heads to increase the power of smaller engines, we chose to keep the proven capability of our larger V-8 truck engines, and save fuel by switching off half of the cylinders when they aren’t needed,” said Jordan Lee, global chief engineer for small block engines.

A combination of simple hydraulic valves and sophisticated software switch off the cylinders when the driver doesn’t need full power. When more power is needed, the system, called Active Fuel Management, seamlessly reengages the additional cylinders.

“With recent increases in computing power, we can combine sophisticated digital design, powerful control strategies, and simple, robust mechanical systems to bring real benefits with no added cost to our customers,” said Lee.  “Think of the difference between a cassette recorder and an iPod MP3 player — more moving parts are not always better.”

By giving customers V-8 power and capability when they need it, with enhanced fuel efficiency when they don’t, Silverado offers the best EPA fuel economy estimates of any V-8 pickup, said Lee. “In fact, our 5.3-liter V-8 delivers EPA fuel economy estimates comparable to some competitors’ V6 engines.”

The mainstream 2013 Silverado 1500 4WD with the available 5.3-liter V-8 has an EPA highway estimate of 21 mpg, matching the estimates for a leading competitor’s 4WD model with a more complex, less-proven boosted V-6.

For customers looking for even better fuel economy, the 2013 Silverado XFE model with the 5.3-liter V-8 has an EPA highway estimate of 22 mpg, retaining all the capability and dependability of other Chevy V-8s.

“For each vehicle program, our task is to choose the best technology for each vehicle and its customers,” said Lee. “For millions of people who depend on their trucks and expect them to last, we believe our V-8 engines with Active Fuel Management are an excellent solution.

Since 2004, approximately 4.6 million of these V-8 engines have employed Active Fuel Management.

“As GM develops future vehicles – including our next-generation full-size trucks and our new midsize Chevy pickup -- we will continue to draw on our company’s unsurpassed global powertrain portfolio, which includes direct injection, clean diesels, vehicle electrification, turbocharging, supercharging, and other technologies,” said Lee.

“But as with our current V-8 engines with Active Fuel Management, the starting point is always what’s the right solution for the customer and the way they use the vehicle.”