Types of Computers in Cars
by Dennis Hartman
It's easy to think of a car as a mechanical system with moving parts and technology from a century ago. However, modern cars make extensive use of computers, setting them apart from the older models from which they evolved. Computers make cars safer, more powerful and more efficient, with promises of even more benefits in the future.
Safety Computers
Some of the most important on-board computers in any car are those involved in vehicle safety. Anti-lock brake systems (ABS) and electronic stability control both rely on sensors in the wheels that indicate a lack of traction. These computers then either engage a motor to pulse the brakes (ABS) or transfer power to wheels that still have traction (stability control).
Air bag control units sense an impact or sudden stop, deploying the airbags in a fraction of a second. Alarms and vehicle immobilizers also use computers to disable the ignition or sound an alarm when someone attempts to enter a locked car or hotwire the ignition.
Performance Computers
Modern cars continue to reach new performance thresholds, largely with the help of computers. Almost all passenger cars today use electronic fuel injection, which is a computer-controlled alternative to carburetors that blends air and fuel in precise amounts for ignition in the engine that provides enough power without being wasteful or producing too many harmful emissions.
Another common performance computer is the automatic transmission, which shifts up and down based on speed, driver input and available engine power. Hybrid-electric vehicles also rely heavily on computers to set the blend of electric and gas power to ensure that the car always gets adequate power in the most efficient way. Computers also manage a hybrid's batteries and regenerative braking system.
Convenience Computers
A car may include dozens of small computers to control all of the various convenience features that drivers have become so accustomed to. Power automatic windows and door locks all use computers, as do self-dimming headlights and automatic windshield wipers. Climate control systems use a central computer to receive temperature data from sensors inside the cabin and adjust the temperature and flow of air to keep the occupants comfortable.
Car entertainment systems are also computer-based, combining CD and DVD players with GPS navigation, hands-free cell phone links, and displays for trip data such as fuel economy and range.
Diagnostic Computers
Finally, the modern automobile includes a computer called the engine control unit, which not only manages the engine during driving but also records any problems or irregularities in overall vehicle performance. One of the first things many auto technicians do is attach a scanner to the vehicle's ECU to access recent error codes and get an idea of what might be causing the problem. ECUs measure emissions, engine compression and electrical operations throughout the car.
