DETROIT – Stepping on the brakes. Hitting the accelerator. Turning the steering wheel.
Motorists of the future might have little tolerance for such old-fashioned ways of operating their cars, thanks to the emerging drive-by-wire technology.
In most cars, it takes an assortment of cables, fluids and mechanical gizmos to translate what the driver does into what the car does.
Drive-by-wire, already used widely in planes, where it is known as fly-by-wire, means employing electronics, rather than mechanical and hydraulic systems, to operate a vehicle.
Steering columns and brake lines give way to sensors and actuators. Steering wheels can be replaced with joysticks or driver control units and human-machine interfaces.
SKF, a Swedish auto supplier known best for making bearings and seals, is one of the companies trying for a piece of the market. Among the others are Delphi, Siemens VDO Automotive and Robert Bosch.
SKF has placed drive-by-wire technology in several prototype vehicles, including the fuel-cell-powered Hy-Wire from General Motors and the Novanta, a Saab-based concept. SKF also developed fly-by-wire technology used in several Airbus models.
Novanta has no accelerator or brake pedals – only a mechanism called a human-machine interface that looks like a cross between an airplane steering wheel and the handlebars of a motorcycle.
Rotate the handles back and forth to throttle the car up or down, squeeze them to brake and turn them side-to-side to steer.
The SKF system uses sensors to read the driver's actions and transfer the information to controllers called smart electro-mechanical actuators. The actuators convert electrical energy into force to perform vehicle functions.
When the driver attempts to turn the car, for example, sensors, rather than a steering column, send that information to the steering rack to turn the wheels.
In addition to the technologies found in Novanta, SKF is working on by-wire systems to handle emergency brakes and clutches.
Eventually, SKF hopes to develop suspension-by-wire to improve vehicle ride and handling, says Steven F. Brown, director of North America programs for SKF's drive-by-wire business unit.
Drive-by-wire systems can help fuel economy, Brown says, because they reduce losses in engine power caused by the continuous running of systems such as power-steering pumps.
In addition, they liberate car designers, removing bulky devices and theoretically allowing the controls for steering, braking and other functions to be placed just about anywhere in the vehicle.
A brake-by-wire system from Siemens "literally cuts the cable from the brake pedal to the brakes," says spokesman Bradley Warner. "Get rid of fluid, fluid lines ... now you can position the brake pedal anywhere you want."
Driver controls on the Novanta fold into the driver-side door when not in use. The control unit on Hy-Wire slides from one side of the vehicle to the other, allowing the car to be driven from the driver or passenger seat.
With their futuristic, gee-whiz designs, drive-by-wire concept cars like Hy-Wire and Novanta are a guaranteed hit at auto shows, but the by-wire vehicles that will first hit the streets will look and feel a lot more like the vehicles we drive today.
Drivers could operate Siemens' brake-by-wire system by hand, but the supplier predicts auto companies will at first opt for a standard foot pedal layout.
"It's just a way of introducing people to the technology. People are accustomed to interacting with their vehicles in a certain fashion, especially older drivers," Warner says. "That's why the keyless vehicle still has keys."
In some cases, engineers working on drive-by-wire vehicles are even using force-feedback technology, similar to what's available in some video game controllers, to mimic the mechanical feel of a vehicle, such as the vibration drivers feel when revving up a car.
"We feel through our hands what's happening, and that helps us understand what's going on with the vehicle and that helps us control it," Brown says. "Eventually, when the Nintendo generation is running the world, maybe you don't need that kind of thing at that point."
They might have no idea, but many drivers have already experienced a version of drive-by-wire: electronic throttle control. That commonly used technology eliminates the cable that traditionally connected the accelerator pedal to the throttle, which is the valve that regulates air and fuel flow.
Also, some high-end vehicles have by-wire parking brakes that automatically lock when the vehicle is parked and release when driving resumes.
Full drive-by-wire systems that include electronic steering might be about a decade away, Brown says. One barrier to wider use of drive-by-wire is the limited electric power available in most cars, usually 12 volts.
Hybrid vehicles, which can generate their own electricity, are therefore a perfect application for drive-by-wire, Brown says.