For the most part, plug-in hybrids rely on the power stored in the battery until that charge is depleted. Unless the switch can be changed manually, it's only then that the cars fire up the internal combustion engine and begin using the fossil fuels on board. This is ideal, of course, when one's drive isn't long enough that the car needs to start sipping gasoline at all. On longer commutes, when it's certain that the route is longer than the car's all-electric range, this isn't necessarily the most efficient use of energy.
Ford is working on a smart system, based on Nokia mapping technology, that uses GPS data to use both the electricity and conventional fuel more efficiently. Since battery power is less efficient at highway speeds, Ford's Green Zone system is designed to save some of that juice for the parts of the drive that require slower speeds, rather than just using up all the electrons right at the beginning of the drive. Using a website or the in-car navigation system, the driver can pinpoint the parts of the route, highlighted in green, where using battery power would be more effective, and set the car to automatically switch to electricity for those sections. Depending on the route, the car could automatically switch back and forth between the two power sources multiple times, particularly if the drive is a mix between city and highway driving.
Ford's Green Zone system is designed to save some of that juice for the parts of the drive that require slower speeds.
Of course, Green Zone will be go beyond that. The program is being developed to take traffic and road grade into account, details that allow the car to be make even smarter choices to improve efficiency. Ford even hopes to have Green Zone learn driver habits, and respond accordingly depending on who is driving the car. The system could control other features as well, such as anticipating corners and shifting the headlights to better illuminate the road ahead. Green Zone could also potentially use information from vehicle-to-vehicle networking to control functions in the car.
The Green Zone system still has a few years before it will be ready to be put into production vehicles, but Ford is confident it will make its way onto the road eventually. As with other innovations that improve efficiency and make our vehicles smarter, we can expect to see similar technology from other manufacturers, until it becomes a regular part of driving in the future.