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Computers and Sensors:
Computers
 Most of us are pretty familiar with the concept of what a computer is and basically what it does. Computers are any electronic circuit that can receive signals (inputs) or modify a signal and find outputs. Finding outputs is just another way of processing information or signals. Computers come in a wide variety of sizes and degrees of sophistication. Some computers are very simple and have limited duties. Others are extremely complex and rely on a vast array of sensors and subordinate computers to interpret large amounts Above Image: Computer Module
of data and tweak automobile performance.
When talking about computers located in automobiles, you’ll frequently hear the generic phrase “ onboard computer .” On-board computer is a great phrase when talking about generic automobile computers or computer systems. While auto manufacturers, industry pros and mechanics  may use the term, they tend to use more specific language. "Module” is often a more specific way of talking about a particular system. For example the “ignition module” is a computer that receives data from sensors and make adjustments to things like ignition timing to tweak engine performance. In other words, module is just a term that allows people to be more specific about which on-board computer they're talking about. Every automobile system has a computer module and each module sends data to a central computer or the real "brain" of the vehicle.
The main computer is called the vehicle control module . It’s primary job is to co ordinate the various system module’s into a seamlessly integrated computer system.
Computer locations
 Computers can be located just about anywhere. The vehicle control module is usually located under the dash on the driver’s side, but it can also be located under the hood, under the driver’s seat or even in the trunk. But no matter where it’s located, computers have to take in a lot of data, process the information and then act.
Computers act on the data they receive
The computer uses the constant data flow to make minor adjustments to various systems to optimize performance or to alert the driver of a condition, like “you’re about of gas” or “the engine temperature is getting dangerously hot.” But a lot of the monitoring and adjustment process takes place without us even being aware that it is going on.
 For example, the oxygen sensor might report to the computer that there’s a little too much oxygen appearing in the exhaust. In response, the computer might signal the fuel injector to adjust the amount of fuel being sprayed into the combustion chamber. But the computer itself can’t make the adjustments, instead it must rely on an army of devices and switches to make the adjustments.
How computer modules make things happen
As we’ve seen, sensors provide information (data) for computers. Depending on the type and frequency of information needed, sensors can either be active or passive. Once computers get the information, it compares it to pre-programmed conditions and can then act on the information to make adjustments.
Actuators
When computers need things to happen, they rely on actuators to convert electrical impulses into action. Conceptually, actuators are pretty simple and act like an on/off switch. When an electrical current is applied, it causes some sort of action, when the current is switched off, the action stops. In this way, actuators can cause mechanical force to be applied by opening and closing electrical currents and make servo motors run, such as the fuel pump.
 Or in the case of the fuel injector , an electrical pulse can cause a solenoid to function like a gate-keeper, allowing fuel to enter the engine or to stop the flow of fuel.
Other types of actuators are designed to manage high voltage electrical currents. Relay switches, for example, are used by the ignition control module to co-ordinate electrical pulses to spark plugs. |
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1. Onboard Computers and Sensors
2. Computer Chips And The Driveway Mechanic
3. Active and Passive Sensors
5. On-board Diagnostics
6. Computer and Sensors Wrap Up
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-> A thumbnail Guide to Auto Computer Modules
-> A thumbnail Guide to Common Sensors
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