The automobile is becoming a rolling microprocessor, with the list of electronically controlled optional and standard equipment growing each model year.

Electronically controlled engines usually lead the list of developments. These "smart" engines, commonplace in new cars sold in this country, automatically adjust themselves to improve fuel efficiency and driveability in response to information supplied by electronic sensors.

Engines do their work by mixing fuel and air and burning the mixture to produce power. Engine sensors help by regulating the air/fuel ratio, fuel injection, exhaust gas recirculation, ignition timing and idling speed.

The transmission, which sends the twisting power of the engine to the drive wheels, has been computerized, too. For example, advanced transmissions use sensors to measure throttle position, vehicle speed, oil temperature and other factors to automatically adjust gearshift patterns. Better fuel efficiency is the result, along with improved acceleration.

Suspension systems, which hold car bodies above the wheels, are becoming more sophisticated. Ride quality, cornering ability and carrying capacity all are affected by the suspension.

Traditional suspension systems are "passive," meaning that they take whatever the road dishes out and try to smooth it out so that the wheels stay on the road and the passengers stay off the ceiling.

But now, domestic and foreign auto makers are experimenting with "active" suspensions -- computer controlled systems that automatically adjust the car's ride to speed and road conditions.

Typical active suspensions have "soft," "medium" and "firm" settings, sometimes designated as "sports" and "normal" settings in certain cars.

The "soft" setting usually is for low-speed driving over bumpy urban streets. The "medium" setting allows a bit more road feel and handling control, and is the setting used most often in everyday driving. And the "hard" or "sports" settings come into play in highway driving, where speed increases the need for precise handling.

Suspension sensors detect changes in vehicle attitude -- pitching motion, body roll, front-end angles -- and then select the "best" damper setting to handle the situation.

Then there is the matter of antilock braking systems, which help to prevent skids by automatically pumping the brakes in panic stops.

ABS, as it is called in the auto industry, works on the same principle as the driver pumping the brakes during a skid, but only much faster, according to technicians at Allied-Signal Inc., a $2.8 billion auto components supplier based in Morristown, N.J.

ABS sensors measure the speed of rotating wheels. Depending on fluctuations in that speed, the sensors electronically adjust brake fluid pressure and pump the brakes up to 12 times a second, reducing the chances for wheel lock and allowing the driver to retain more steering control over the vehicle.

Antilock brakes initially were installed in expensive cars, in keeping with a longstanding auto industry pattern of introducing new consumer technology at the high end.

But the price of the computerized braking systems, about $1,000 per unit in the early 1980s, has fallen to nearly half that amount today. As a result, some auto industry officials expect to see antilock brakes as standard equipment on most cars sold in the United States by 1995.

And among more things to come are radar-equipped collision avoidance systems designed to prevent car crashes; computerized navigational systems to help drivers reach their destinations by using the most efficient routes, and "drowsiness warning systems" that will monitor a driver's pattern of using the vehicle's controls and determine whether changes in that pattern indicate drowsiness. Based on the drowsiness warning system's determination, an indicator light will flash and a buzzer will sound to awaken the driver.

Really.

Nissan Motor Co. Ltd. already is testing such a system on some of its production cars.