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2013 Audi A5: Each of the four TDI diesel and three TFSI gasoline units in the new engine lineup include forced induction and direct fuel injection. (Audi)
2013 Audi A5: Each of the four TDI diesel and three TFSI gasoline units in the new engine lineup include forced induction and direct fuel injection. (Audi)

How it works

How it works: Cars and computers Add to ...

In the face of tough new regulations and the endless drive to improve fuel mileage, vehicle manufacturers are placing increased emphasis on computers and electronics. New fuels, electricity, hybrids, weight reduction and aerodynamics all play a role, but electronics are critical to the management of the internal combustion engine, which will be the mainstay of the industry for many years to come.

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The vast majority of advances or improvements in fuel efficiency have been made possible by electronics, more specifically semiconductors that monitor or control various components or systems in a vehicle. It's estimated that more than 50 electronic control units are at work in a typical 2011 passenger vehicle. From headlight to tailpipe, wiring harnesses are being replaced by networks. The principal goals are improved emission and fuel consumption numbers, but there are significant byproducts of this revolution: improved safety and reliability.

These electronic components must operate in an extremely harsh environment - without fail. Imagine if you were to leave your laptop computer out overnight in the winter, even if it was covered. How about putting it in the desert - on the hottest day of the year, or in the rain or fog or blowing snow? Would you expect it to work, instantly?

The automobile, and its various components, encounters these conditions regularly. But save your pity for the stuff under the hood, which not only has to deal with ambient conditions, but extremely high heat loads. Even on the hottest 35-degree day it is worse in the engine compartment where everything is crammed into the closest possible quarters, tight up against an engine that is burning fuel and generating exhaust gasses that range in temperature from 250 to 680 degrees C. A long struggle up a hill in a turbocharged engine can generate exhaust gas temperatures in excess of 700 C.

These tiny little components are expected to measure things and make adjustments in microseconds - regardless of temperature or other conditions. In order to meet the new emission and fuel economy standards, engineers have to devise systems that will be able to exercise tighter control over every moving component as well as the actions of stationary items.

With pistons, valves, crank- and camshafts moving at terrifying speeds and spark plugs firing several times during each ignition cycle in each cylinder, it can get hectic. Toss in the fact that the electronics have to measure every one of those motions and actions - all the time - and make corrections or alterations at several individual points during the process and you might gain fresh appreciation of the work taking place to keep things running smoothly - whether it be a $9,999 econo-box or a $340,000 exotic car.

One example to illustrate what could only be possible through electronics is the growing trend toward direct injection. These systems inject precise amounts of fuel directly into the combustion chamber of each cylinder at very specific moments in time. The control unit responsible for injecting the fuel and igniting it requires immense processing speed and memory. It has to sort through a vast list of parameters every microsecond depending on everything from engine speed and throttle position to exhaust gas temperatures and camshaft and valve positions. Based on this information, it knows when to send a signal to the spark plug and ignite the fuel air mixture.

Engineers are requiring each individual microchip, many of which are used on every circuit board within the various control units of a vehicle, to have a minimum of three and as much as 12 megabytes of memory. They are also looking for smaller and faster chips.


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