Fuel injection system having fuel injector calibration

An internal combustion engine fuel injection system including an electromagnetic fuel injector selected from a number of injectors having fuel flow characteristics varying from one another, the system comprising, in combination:

• a calibration resistor having a resistance value representing the percent deviation of the actual predetermined fuel flow rate of the fuel injector from a design value K;
• a memory having plural memory locations, each memory location being addressed by a specific resistance value and having stored thereat a corresponding percent deviation of the actual injector fuel flow rate from the value K;
• means effective to measure the values of predetermined engine operating parameters indicative of engine fuel requirements;
• means responsive to the values of the predetermined engine operating parameters effective to determined the fuel flow requirements M.sub.F for each injection event;
• means effective to sample the resistance value of the calibration resistor;
• means effective to retrieve from the memory the percent deviation stored at the memory location addressed by the sampled resistance value of the calibration resistor;
• and
• means effective to energize the fuel injector for a time equal to ##EQU4## where E is the retrieved percent deviation, whereby the calibration resistor provides for a measure of the fuel injector characteristics so that the injection amount for each injection event is independent of varying injector-to-injector fuel flow characteristics.