The need to control the emissions from automobiles gave rise to the computerization of the automobile.
Hydrocarbons, carbon monoxide and oxides of nitrogen are created during the combustion process and are emitted into the atmosphere from the tailpipe.
There are also hydrocarbons emitted as a result of vaporization of gasoline and from the crankcase of the automobile.
The emission clean air act of 1977 set limits as to the amount of each of these pollutants that could be emitted from an automobile. The manufacturers answer was the addition of certain pollution control devices and the creation of a self adjusting engine. 1981 saw the first of these self adjusting engines. They were called feedback fuel control systems. An oxygen sensor was installed in the exhaust system and would measure the fuel content of the exhaust stream. It then would send a signal to a microprocessor, which would analyze the reading and operate a fuel mixture or air mixture device to create the proper air/fuel ratio.