When navigating the highway, your car travels at a set speed without taking full advantage of the engine’s power, but consuming precious fuel. That V6 or V8 under the hood could be much more efficient if it employed an important piece of modern technology: cylinder deactivation. Does your vehicle have this feature? If so, what exactly does it do and is it a good thing? Read on to learn what some automakers are doing to save fuel without making significant changes to your vehicle.

High fuel prices leave consumers scrambling for answers. Some are switching to hybrids, others to diesel, while others are choosing smaller and lighter vehicles, all in an attempt to save fuel. While no one knows exactly what fuel prices will be in the long run, automakers can get better gas mileage through a fairly simple technological change: cylinder deactivation. Cylinder deactivation works like this: Let’s say you’re cruising the interstate at a set speed of about 65 miles per hour. The road surface is flat, so there is not much demand for your engine. Instead of running all six or eight cylinders, why not run the engine on three or four?

In the early 1980s, GM tried this unsuccessfully with Cadillac by offering what they called 8-6-4 displacement. Unfortunately, the technology was not as refined as it is today and the experiment failed miserably. Today, however, thanks to the chips in the central processing unit, on-demand scrolling is a viable alternative. When cruising, sensors tell the engine to turn off half its cylinders, reducing gas mileage. Although typical profits range from 5% to 7%, a widespread introduction of this technology could reduce our dependence on foreign oil and increase business fuel economy across the board.

GM has been offering active fuel management for three years. [or AFM] with various V8 engines and technology will soon find its way into the V6 engines for the Chevy Uplander and Impala. Honda has its own variable cylinder management [or VCM] for select V6-powered Odyssey, Accords and Pilots models. Other automakers are looking into cylinder deactivation and more manufacturers are expected to step in.

Unlike previous attempts to shut down the engine, the last attempt to shut down unnecessary cylinders appears to be successful. Thanks to refinement of hydraulic valve lifters and improved engine and exhaust tuning, engines with cylinder deactivation technology can switch from a fuel-saving mode to one that requires maximum power quickly and quietly. Therefore, consumers get the best of both worlds: power and maximum fuel efficiency.