Variable Cylinder Management

Each manufacturer has its own name for this technology. It's been called Displacement on Demand, Cylinder Deactivation, and of course Variable Cylinder Management. No matter what it's called, it does the same thing: cylinders disengage while cruising.

A six cylinder engine is more efficient if three cylinders are working hard and three are at rest than if all six were operating at a reduced load.

All engines have a most efficient range, and variable cylinder management allows an engine to operate within that range for more of its run time. More time operating at increased efficiency means better fuel mileage.

As talented engineers do everything they can to overcome the obstacles to efficiency, equipping a six cylinder engine with variable cylinder management can add a significant amount of mileage.

Right now, variable cylinder management is available on the 2005 hybrid Accord, mild hybrids planned for production by GM, and the 2005 Jeep Grand Cherokee (non-hybrid).

At the time of this writing, there are no four cylinder models equipped with variable cylinder management, but that may change as more fuel efficient vehicles come to market.

Certainly, as more six cylinder future hybrid models become available, variable cylinder management will become common technology.