For 111 years, the Rolls-Royce experience has been all about wafting, often in chauffeur-driven comfort. Now the stunning Wraith coupe adds a computerized wingman, using GPS data to automatically select the perfect gear for the road ahead. The Wraith’s Satellite-Aided Transmission (SAT) is a production-car first for the BMW-owned Rolls-Royce.
Rolls-Royce engineer Phil Harnett, formerly with BMW’s Formula One team, saw a colleague working on SAT as a predevelopment project. “I saw how perfect it was for Rolls-Royces—dynamic yet effortless—and brought it into the Wraith,” Harnett says.
This yachtlike fastback coupe marries a 465-kilowatt (624-horsepower) V-12 to the silken, eight-speed automatic transmission produced by the ZF Group, based in Germany. But the Wraith takes the ZF unit to the next level, adapting to a driver’s individual style and applying GPS route and location data to anticipate and change gears. The engine’s electronic control unit adds an algorithm that responds to upcoming road patterns.
Rolls-Royce spokesman Gerry Spahn says the system works especially well on curvy terrain, off-ramps, or roundabouts. As the car heads into a series of curves, for example, the SAT will automatically hold a lower gear to prevent midcorner upshifts and to avoid upsetting the car’s occupants with needless gear changes. In testing on public roads, the system has reduced the number of automated shifts by up to 30 percent, Spahn says. Besides reducing wear and tear on the transmission, the system also improves responsiveness and fuel economy. Because it requires no additional components beyond existing sensors, controllers, and the navigation system, no weight is added to the vehicle.
The SAT isn’t mapped for altitude and topography, so it can’t anticipate hills and change gears accordingly. But that kind of functionality could be baked into a future version.
“Customers have asked about altitude,” Spahn says. “It’s not technically impossible; it just hasn’t been applied.”