It's 1968, your Chevy isn't running right, it idles rough and stalls. A quick trip to the local garage reveals that the carburetor needs an adjustment. It seems that the air/fuel mixture is a bit too lean -- the carburetor needs an adjustment. A quick turn of the adjustment screw straightens out the problem and you are off! Now, let's step into the time warp and zingggggggggggg!!!
It's 2003. Your Chevy's computer detects a slightly lean condition in the air/fuel mixture. A signal is sent to the fuel injection system and the mixture is enriched to meet the need of additional fuel. Adjustment completed!
The purpose of this article is to explain how the systems of automobiles have changed, as well as auto repair technology. Let's take a brief look at this evolution.
Performance systems: Engine management systems now control the car's engine. The computer receives data in the form of signals from various sensors located throughout the engine. These sensors are reading engine temperature, the amount of oxygen in the exhaust, the amount of air flowing into the injection system, and the position of the throttle (or gas pedal), just to mention a few. This data is analyzed by the computer and translated into commands called "engine controls." These commands are sent to various components that actually make onboard engine adjustments while the car is running -- giving your car maximum performance. Such adjustments as fuel mixture, ignition timing, engine cooling, and engine idle are constantly monitored and adjusted to compensate for varying operating conditions at the rate of milliseconds! Pretty wild!
Transmissions: Transmissions used to be governed by hydraulic oil pressure and engine vacuum. Not any more! Today's transmissions are governed electronically through engine control. For instance, if your car's performance system senses that a heavy load has been placed on the transmission for any reason (i.e.: passing a car, additional payload, pulling a trailer, or driving up a hill), a signal will be sent to the transmission to downshift into a lower gear. Transmission operation is governed through speed sensors and solenoids and controlled through electronic valve bodies, solenoid packs, and lockup torque converters.
Brakes: Remember when you went to driving school? What did the instructor tell you to do on slippery pavement in order to slow down the car safely? Pump the brakes, of course! This is not necessary with the computer-controlled antilock brakes of today. Your brakes are now "very smart" with the antilock computer. Here's how it works. Each wheel has a wheel-speed sensor that monitors the speed at which the wheel turns. When the car is stopping on slippery pavement, the wheel-speed sensors recognize when the wheels lock up and skid. If a skid occurs, the antilock computer then takes control of the braking system and starts "pumping the brake" of the wheel that is locking up. This could happen at more than one wheel at a time. The antilock system allows for safe controlled stopping and handling on all pavement conditions.
With all the technological advancements, it stands to reason that auto repair technology had to "get smarter" too. The test equipment from 30 years ago doesn't hold a candle to today's test equipment. Digital volt/ohm meters now have the capability of measuring electricity in extremely small units compared to older models. "Fast Track Software" is smart software that can trace down the problems in today's cars through a built-in diagnostic process that is self-executing. "Multiplexing" is a new way to decrease the amount of wiring in your car. The concept is simple -- use one wire to feed several sensors at once. Each sensor has a signal it "recognizes" that is unique to it. When a sensor picks up its signal, it is activated to do its job! Pretty smart!
"Flashproms" are computer chips that dictate to the car's computer how to operate the performance system. In the event of a performance problem, information stored in these chips are sent from your local dealership via satellite to the manufacturer. The data is then analyzed, adjusted, and sent back to the dealer via satellite and downloaded into your car's computer and -- problem solved!
Cars have come a long way in a relatively short time. Who knows what the upcoming millennium will bring?!
