How Computers work in Automobiles




Now modern cars have millions of microprocessors installed to complete a numerous amount of tasks. Almost your whole car is run by a computer; of course it is the work of the engine and all the parts put under the hood that drives it, but the microprocessors tell the parts what to do. There are microprocessors for everything, from cruise control to engine control. For this system to operate fully, your car must have all the parts needed to build the computer and all the parts it controls. Here is a list of components that show just how complex this system is.
ECU to a ford Ranger


MICROPROCESSORS
When automobiles were first invented, none of these microprocessors were necessary and were also non-existent. So why such the increase in microprocessors to cars? Should it not make them more complicated? These extensive numbers of computers in cars actually simplify many of the tasks to create a vehicle. First off, there are new laws and standards that cars must meet. Engine controls must meet emission laws and fuel economy standards; meaning something must control the amount of pollution leaving the exhaust and the car must get a reasonable mile to the gallon. Computers also help give advanced diagnostics and help mechanics quickly discover a problem. They also simplify the manufacture and design of cars, as well as simplify the wiring. Microprocessors are also proving to help with safety, convenience, and comfort features.

The most important microprocessor is the ECU (engine control unit), which controls engine functions like the spark timing and obtaining the correct fuel and air mixture to intake into the engine block, which is then compressed and sent out the exhaust. The ECU uses a closed-loop control to monitor the outputs of a system so it can control the inputs. This control scheme also manages the emissions and the fuel economy of the car by creating the perfect ratio of fuel/air mixture. The ECU gathers information from tons of sensors and performs millions of calculations in seconds to determine things like deciding on the best spark timing, and determining how long the fuel injector should be open. This is all done to ensure the lowest emissions and the best mileage.
The Engine Control Unit normally contains a 32-bit, 40 MHz processor; this is very small compared to a normal PC with a 500 – 1,000 MHz processor. Cars do not need as much power because they are running much more efficient codes than a personal computer. An average ECU code takes up less than one megabyte of memory; PC’s may have two gigabytes of programs on them, which is 2,000 times more than the amount in an ECU. The processor can be found with hundreds of other components on a multi-layer circuit board, like what our class labeled during a lab session.

There are many other things found on a cars circuit board. One part is the analog-to-digital converter which converts analog voltage into a 10 bit digital number. This is necessary because the processor only understands digital numbers; 0’s and 1’s, like normal computer. For example, the oxygen sensor outputs volts and these must be converted to digital numbers for the processor to read. There also has to be a digital-to-analog converter so that when the ECU has to provide an analog voltage to drive an engine component, the converter can read the digital number it outputs (because the ECU can only understand bits) and turn it into a voltage before sending it to do its job. Another component is the high-level digital outputs which are sent by the ECU and are either on or off. Some of the tasks this is responsible for is firing the spark plugs and turning the cooling fan on and off. These are outputs that are either on or off, there is no in between. The signal conditioner is also important because it adjust the signals for inputs and outputs so the converters can read them. For example, the analog-to-digital converter may be set to read a 0 through 4 V signal, but the oxygen sensor outputs a 1.1-V signal. The signal conditioner can then use multiplication to get a better reading; like multiplying by four so you have a 4.4V signal which is more accurate for the converter to read. Finally, the communication chips are very important. They are responsible for the communications standards used in cars. One that is widely used is called CAN (controller-area networking), it has communications speed of up to 500 kilobytes per second on the communications bus.

Here is more information on how the engine control unit works on a car

Microprocessors make finding out what is going wrong with your vehicle much easier than before. Each module in the system can communicate with a central module through the communications bus to report any problems going wrong with its system. The center module can then relay the message to the off-board diagnostic tool (shown on the right) of what the problem is. Most of the time the mechanics can find the problem just by looking at that tool. Many cars have fault codes that automatically tell what is wrong with your car. Usually the check engine light blinks a certain amount of times to tell you what has gone wrong. This is a list of some of the fault codes for certain makes.

Modern cars are much easier to manufacture and design thanks to new technology. For example, the Instrument Cluster is a vital part of driving a car. It is built by a supplier, making it easier on the car manufacturers. The ECU gathers information like the engines speed and the coolant temperature and sends it to the Instrument Cluster Module. The package consists of a header which is a number representing either the temperature or the speed and then lists the data, which is the reading, like the actual engines speed. Then the module updates the gauges and indicators on the instrument panel. Another new technology in cars is the smart sensors. These sensors have built in microprocessors to read the voltage of pressure applied to the sensor. The computer then converts the voltage to digital numbers automatically and then sends the information onto the bus. This is much more efficient because digital numbers do not pick up as much electrical noise as analog voltage, and when a volt is sent onto the bus it can gain or lose volts before reaching its desired destination, making it an inaccurate reading. These smart sensors are also helpful to the manufacturers because they are made by the supplier, so it is one less thing the carmaker has to worry about.

Another great advantage to computers in cars is multiplexing. This is a method that simplifies the wiring, preventing wires from getting out of control. Each module is controlling a small aspect of the car, and these modules are attached to the communications bus which can carry it wherever it needs to go. For example, when you hit the window button in your car the drivers door module sends that information to the bus, which gives it to the body controller which opens activates the windows motor. This is much more efficient then running wires from every switch and sensor to the part it controls. The Volvo S80 is a great example of the new technologies of multiplexing. Learn more about this car and how multiplexing works in it.

Another great advantage to computers in cars is multiplexing. This is a method that simplifies the wiring, preventing wires from getting out of control. Each module is controlling a small aspect of the car, and these modules are attached to the communications bus which can carry it wherever it needs to go. For example, when you hit the window button in your car the drivers door module sends that information to the bus, which gives it to the body controller which opens activates the windows motor. This is much more efficient then running wires from every switch and sensor to the part it controls. The Volvo S80 is a great example of the new technologies of multiplexing. Microprocessors are also to thank for saving lives; they control important safety features that have proved to save lives throughout the years. They control the anti-lock brakes system (ABS), the airbags, and more recently the traction-control and stability-control systems. Each one of these new features requires another module which contains many microprocessors. The Volvo SCC previews some of the future safety features that we may see more of. This vehicle is capable of adjusting the seat, steering wheel, floor, pedals, and the center console by scanning sensors in the position of the driver’s eyes to adjust the most comfortable position for the driver. It also has adaptive headlights which adjust the lighting according to the speed and steering of the car. The rearview mirrors and rear bumper are active and alert when approaching traffic is entering the drivers blind spot. It even has a remain-in-lane advancement which monitors the cars position in relation to the centerline and side-marker lines for 20 meters ahead of the car. When the car starts to swerve out of its lane, then it alerts the driver.
Click the volvo to learn more about its extrodinary safety features

Wow, so if they can do that much with microprocessors, who knows what else they will come up with.

We are already starting to see new features like wireless internet access in your car, personal LCD touch screens that can link you to the internet or play movies. There is also the advancement in satellite radio, which can travel up to 22,000 miles; you will not miss any stations with that feature, and MP3 players can convert music from your home to your car. We are now seeing more voice commands which can control your audio features, climate-control, phone, and even email. The Dodge Super8 Hemi introduces new advancements like these, it seem like a car from the future. But could the real future in cars have anything to do with flying? Here is some information on the history of attempts to create a flying car and the reality of the future.


In the USENET Newsgroups i learned that most people are happy with the new technology being introduced to automobiles but in one discussion, someone said that the technology takes away from the character of the car, im not sure what that is supposed to mean but according to them, the more technology there is, the less interested they are in cars. There are also concerns that the technology will potentially invade our privacy. It is possible that the big brother technology can get into the wrong hands and can be used like spys in people's cars. This is the discussion of the issue.