Apparatus for determining the duration of fuel injection control pulses

摘要

A fuel injection system receives valve control pulses, the length of which determines the fuel quantity delivered to the engine. A first counter receives a pulse train whose frequency depends on the air flow rate and this pulse train is admitted for a period defined by the engine speed. The content of the counter is then counted out at a frequency which is synthesized from operational parameters of the engine, including, in particular, the temperature. For this purpose, there is generated a temperature-dependent frequency which is fed to a multiplier circuit which combines this frequency with data derived from a memory to generate an output signal which is further processed to provide the fuel injection pulses for the engine.