BOSTON — It may look like a car, but that's actually a four-wheeled computer you're driving.
The electronic processing power in today's cars is equivalent to "several high-end multi-processors," says Chuck Powers, an engineering manager at Motorola in Austin, Tx.
And that computing power has brought technology never dreamed of 20 years ago, even in science fiction, right into family garages.
Initially, processing power was added to meet emissions regulations, later to enhance safety and convenience.
Now, it's pervasive in driving and running a car.
Electronics can accomplish tasks that would be prohibitively expensive mechanically, Mr. Powers says. Perhaps more important, they save weight in some existing mechanical systems, and that helps automakers meet fuel-economy regulations. Already electronics can control so many vehicle systems that demonstration cars can drive themselves in controlled environments.
Following is a list of electronic technologies already available and in some cases universal on new cars.
The most advanced computer control in all 1997 and newer cars is the government-mandated on-board diagnostics system. It monitors all engine functions and other engine related electronics systems so as to maintain tiptop emission controls. The system also pinpoints trouble spots for mechanics and provides a wiring foundation for most of the car's other electronic systems.
One of the most wide-reaching advances, ABS, as the system is commonly called, uses sensors on each wheel to detect rotation speed. When a central computer interprets a significantly higher deceleration rate at one wheel than the others, it momentarily reduces brake pressure on that wheel to allow it to start rolling again, then clamps the brakes back on.
Skidding wheels can't steer. So ABS works hundreds of times per second to ensure that the driver can steer around obstacles while braking as hard as possible. The system provides maximum braking force short of allowing a skid.
An inexpensive (for the automakers) extension of antilock brake technology, traction control uses the same hardware - sensors, computer, and brake controls - to slow down spinning wheels. When the car starts on ice, for instance, the traction control computer brakes the spinning wheel until its speed matches the other drive wheel's. So both wheels get traction.
Some expensive traction control systems go further. They actually reduce the engine's power in addition to applying the brakes. This means that the driver's foot no longer directly controls the throttle, electronics systems do. When the driver floors the gas, the pedal sends a signal along a wire, telling a computer how much the driver wants to accelerate. The computer then decides whether to open the throttle wide or - if it receives a signal that a wheel is spinning - to throttle back. No matter that the driver is still standing on the gas pedal.
Another ABS add-on, stability control works to prevent spins and understeering - plowing ahead in a corner. The system uses a sensor to measure steering-wheel angle and a yaw sensor, which measures the rate the car's body is actually turning at. Some systems also monitor speed, throttle, and wheel rotation. If the computer finds a difference between steering angle (where the driver wants to go) and yaw angle (where the car is actually going), it brakes one or two wheels to correct course.
For example, if a car is spinning to the right, stability control will slow only the left front and right rear wheels to rotate the car back into line.
Active suspension measures wheel movement over bumps and adjusts suspension firmness accordingly. Engineers have always struggled with the trade-off between a smooth ride, which requires a soft suspension, and good handling, which requires a firm one. Active handling makes the same car do both. Suspension sensors measure the frequency, abruptness, and height of bumps and pass the information on to a computer.
The computer interprets sharp, high-frequency movements as bumps and opens valves in the shock absorbers to soften the ride. When the car heels over in corners, the tall, low-frequency suspension movements trigger the computer to add resistance to the shock absorbers.
Some active suspension systems can also raise and lower the car to help passengers get in and out or to improve aerodynamics on the highway.
Laser-Braking Cruise Control
The biggest problem with conventional cruise control is what happens when traffic in front slows down. It's useless in city congestion. The next generation cruise control due on the top-of-the-line Mercedes-Benz in 2000 uses a laser to measure the distance to the car in front. If you get too close, the cruise control automatically slows down. When traffic opens up again, it automatically resumes the speed you set.
Electronic Parking Aid
Also a Mercedes-Benz feature, this uses the same laser as the next-generation cruise control plus one in back. It works like the wire "curb feelers" on Grandma's Cadillac. When you are parallel parking, the lasers measure the distance to the cars in front and behind. Get close, and a beep sounds inside. The beeping gets faster the closer you get.
Unlike ABS, this feature on almost all Mercedeses actually helps the car stop faster. According to Mercedes studies, most drivers apply the brakes too timidly in panic stops because they're afraid of being rear-ended or skidding or because they don't know they can step on them harder.
Brake assist uses a computer to measure how suddenly the driver depresses the brake. Fail to press the pedal far enough, and the computer uses ABS components to clamp the brakes on fully. Mercedes claims a 15 percent improvement in stopping distances for most drivers.
GPS Navigation Systems
Many automakers offer global positioning satellite navigation systems in their luxury cars. The systems combine a touch screen in the dashboard, a flat satellite antenna, and a gyroscopic sensor to track which way the car is pointing. The system satellites triangulate the car's position to within 10 yards and plot it on a map on the dashboard screen. The system can locate businesses, bank machines, attractions, and street addresses through an onboard CD-ROM database. The driver can enter a destination, and the system will sound out turn-by-turn directions as the car arrives at each intersection.
Hands-Free Cellular Telephones
Many luxury cars come with an integrated cellular phone that includes speakers and a microphone hidden in the car, so drivers can keep their hands on the wheel and their eyes on the road. The phones automatically mute the stereo during calls and allow the driver to dial by speaking the phone number.
General Motors combines satellite navigation and a hands-free cellular phone with this security system. The cellular phone is also linked with some car controls. Think of it as your friendly, helpful, slightly overbearing Big Brother. On-Star has no navigation screen or in-car CD-ROM database. Instead, it has a room full of workers in Michigan at your beck and call.
Lost? Press the On-Star button on the built-in phone. Call-center employees can see your location on a screen and give you directions by phone. Lock your keys in the car? The center can unlock it. (You just dial an 800 number from the nearest pay phone.) Car stolen? The center always knows where it is. Broken down? Service people can find you. In an accident? Any time the air bags go off, the car automatically calls the center and help is dispatched.
Ford offers a similar, but less comprehensive system called Rescue. Observers expect On-Star eventually to include a conventional GPS navigation system screen.
Intelligent Automatic Transmissions
These transmissions use computer logic to better simulate the gear selection a driver would make with a manual transmission. The simplest will put the transmission in a lower gear when you are going downhill, rather than upshift and make you brake harder. They also downshift earlier at stoplights. More advanced transmissions use a computer memory to track how aggressive a driver's mood is and adjust shifts accordingly.
Intelligent Sound System
A new Bose 4.0 sound system in the 1998 Cadillac Seville measures noise interference in the car, such as a passing truck or extra wind when a window is opened, and automatically amplifies the particular frequency range drowned out by that noise. So the music always sounds the same.
Many cars today are sold with remote transmitters to lock and unlock the doors, open the trunk, and turn the alarm on and off. The latest include functions to raise and lower windows and even open and close a convertible top - useful, for instance, if it starts raining after you left the top open and you can see the car from your restaurant table.
Most new Mercedes-Benzes have no traditional ignition key, but use a laser-activated electronic code in the lock remote control. A traditional key that fits the single door lock is embedded in the remote, in case the battery goes dead. Next, the company plans to use a security pass card, as in office buildings.