Vehicle technology has been rapidly developing for many years and, like other industries, has largely turned towards computer control for the regulation of important management systems. Along with advances in electronic ignition and fuel injection this level of control has allowed timing and fuel delivery to be precisely regulated and monitored, giving improvements in power, fuel economy and emissions.
Electronic engine management has now completely replaced the conventional carburetter and mechanical ignition systems that were the industry standard some years ago. As the modern engine runs, hundreds of measurements are taken and adjustments have to be made every minute.These are carefully monitored by the brain behind the whole operation - the vehicle ECU, orElectronic Control Unit.The ECU is a small computer in it's own right.
Inside the ECU can be information on all aspects of the vehicle, from simple data such as model, year and engine type to more complex data such as that used in the control of ABS or vehicle stability systems and engine operating conditions.. Also stored inside the ECU is information that relates directly to the control of fuelling and ignition timing.
Changing information is received from engine management sensors such as throttle position, air flow and engine speed, and the ECU uses these inputs to determine optimum values for how much fuel to inject and when to fire the spark. To do this the ECU compares the received information to large areas of predetermined reference data stored within a chip on the circuitboard.
These areas of data are known as memory maps - vehicle "mapping" as it is known. As the inputs are constantly changing during driving, so are the values returned from these memory maps, meaning that the settings for fuel and ignition will remain appropriate to any particular driving situation.